TWI430042B - Catadioptric projection objective with pupil mirror, projection exposure apparatus and projection exposure method - Google Patents
Catadioptric projection objective with pupil mirror, projection exposure apparatus and projection exposure method Download PDFInfo
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Description
本發明有關於一種反射折射投影物鏡,用於將設置於該投影物鏡之一物面中的物場成像於設置於該投影物鏡之一像面中之像場。The invention relates to a catadioptric projection objective for imaging an object field disposed in an object surface of the projection objective on an image field disposed in an image plane of the projection objective.
反射折射投影物鏡,舉例而言,係被應用於投影曝光系統中,特別在於晶圓掃瞄器或晶圓步進機(stepper),用來製造半導體裝置以及其他微型裝置,以及,被用於投影光罩或光柵上之圖案於有易感光塗料且於一小範圍內具有高解析之物體。Reflectively reflective projection objectives, for example, are used in projection exposure systems, particularly wafer scanners or wafer steppers, for the fabrication of semiconductor devices and other micro devices, and are used in The pattern on the projection mask or grating is such that it has an easily sensitized coating and has a high resolution in a small range.
為創造更精細的架構,一般會追求提高投影物鏡之像端的數值孔徑(NA),以及應用更短的波長,尤其是波長短於260奈米(nm)之紫外光線。然而,非常少數的材料,尤其是合成水晶以及結晶氟化物,於波長區段足夠透明而可供製造光學元件。由於可供製造光學元件之此等材料的阿貝數(Abbe number)之間通常太過接近,因此很難提供純的折射系統以達到足夠良好的色彩校正(校正色差)。In order to create a finer architecture, it is generally sought to improve the numerical aperture (NA) of the image end of the projection objective, as well as to apply shorter wavelengths, especially ultraviolet light having a wavelength shorter than 260 nanometers (nm). However, very few materials, especially synthetic crystals and crystalline fluorides, are sufficiently transparent in the wavelength section to make optical components. Since the Abbe numbers of such materials for making optical components are typically too close together, it is difficult to provide a pure refractive system to achieve a sufficiently good color correction (corrected chromatic aberration).
在光學微影技術中,高解析以及良好之校正狀態可經由相對較大且實質上為平面的像面來達成。目前被認為在光學設計中最難達成的一項要求為一平像,尤其若這是個全反射設計。提供一平像需要反抗的透鏡的折光率,而因此其導至更強的透鏡、更長的系統長度、更大的系統玻璃質量、以及因更強的透鏡曲率所造成之更大的高階像差。In optical lithography, high resolution and good correction states can be achieved via relatively large and substantially planar image planes. One of the most difficult requirements to achieve in optical design is currently a flat image, especially if this is a total reflection design. Provides a flat image that requires refraction of the lens's refractive index, and thus leads to a stronger lens, longer system length, greater system glass quality, and greater higher-order aberrations due to stronger lens curvature .
凹鏡有時候被用來幫助解決色彩校正以及平像場之問題。凹鏡有正向的折光率,有如一正透鏡,卻有負的帕茲伐曲率(Petzval curvature)。而且,凹鏡不會導致色彩問題。因此,結合折射和反射元件之反射折射系統,尤其是透鏡以及至少一個凹鏡,係主要用於設定先前提及之高解析投影物鏡。遺憾的是,凹鏡很難被整合於光學設計中,原因在於其將來自某方向之輻射以同路徑反射回去。目前需求一種智慧型設計以整合凹鏡,而不造成機構上之問題、或因光束漸暈(beam vignetting)或光瞳遮蔽(pupil obscuration)所造成的問題。Concave mirrors are sometimes used to help solve color correction and flat field problems. The concave mirror has a positive refractive index, like a positive lens, but has a negative Petzval curvature. Moreover, the concave mirror does not cause color problems. Thus, a catadioptric system incorporating refractive and reflective elements, in particular a lens and at least one concave mirror, is primarily used to set the previously mentioned high resolution projection objective. Unfortunately, concave mirrors are difficult to integrate into optical designs because they reflect radiation from a certain direction back along the same path. There is a need for an intelligent design to integrate concave mirrors without causing structural problems or problems caused by beam vignetting or pupil obscuration.
由於對微影製程之效率之需求增加,目前傾向增強光源強度。並且,漸漸地更短的波長也被使用。特定的照明設置被利用以對各種不同的圖案種類之成像條件最佳化。因此,於投影系統中之光學材料,隨時間而產生之各種不同的變化的特性被觀察,這些都明顯地影響曝光系統之成像品質。由於操作中逐漸增加之吸收而使透鏡組以及其他透明光學元件加熱(透鏡加熱),其不斷地影響成像特性。而且,由輻射引發之折射係數的改變所造成之長期(半穩態)影響(例如壓密效應(compaction effect))會被觀察。Due to the increased demand for the efficiency of lithography processes, there is currently a tendency to increase the intensity of the light source. Also, gradually shorter wavelengths are also used. Specific illumination settings are utilized to optimize imaging conditions for a variety of different pattern types. Thus, the various properties of the optical material in the projection system that are produced over time are observed, which significantly affects the imaging quality of the exposure system. The lens group and other transparent optical elements are heated (lens heating) due to the gradual increase in absorption during operation, which constantly affects the imaging characteristics. Moreover, long-term (semi-steady-state) effects (such as compaction effects) caused by changes in the refractive index induced by radiation are observed.
申請人之美國專利申請案,申請案號2004/0144915 A1,說明在具有物理分束器之反射折射投影物鏡中,因吸收所導致之加熱影響,所造成之問題的一種解決方式。申請案揭露一種被設計為單一成像系統(沒有中間影像)之可折式反射折射投影物鏡,而其中一凹鏡係設置於瞳狀表面上。具有偏光選擇之物理分束器表面的物理分束器(beam splitter)被提供來分離自軸向上物場朝凹鏡之輻射以及自凹鏡反射至像面之輻射。凹鏡係由變形面鏡所構成,而凹鏡表面之形狀可用光瞳鏡操作器來控制,其係以補償在操作投影物鏡時,反應因輻射所導致之光學效能變化而產生之某些依時間變化的成像像差。光瞳鏡操作器有簡單的結構,且被安裝於凹鏡的背面而不影響光學路徑。變形光瞳鏡被設計來補償以下情形,如像散性(astigmatism)、立方分束器以及矩形相位延遲板(retardation plate)因吸收導致之加熱,所造成之二重(two-fold)或四重(four-fold)之波前(wavefront)形變,以及壓密效應等。The applicant's U.S. Patent Application Serial No. 2004/0144915 A1 describes a solution to the problem caused by the absorption of heat caused by absorption in a catadioptric projection objective lens having a physical beam splitter. The application discloses a foldable catadioptric projection objective designed as a single imaging system (with no intermediate image), and one of the concave mirrors is disposed on the braided surface. A beam splitter having a polarizing-selective physical beam splitter surface is provided to separate radiation from the axial object field toward the concave mirror and from the concave mirror to the image plane. The concave mirror is composed of a deformed mirror, and the shape of the concave mirror surface can be controlled by a light mirror operator, which compensates for some of the dependence of the optical performance change caused by the radiation when operating the projection objective. Time-varying imaging aberrations. The light mirror operator has a simple structure and is mounted on the back side of the concave mirror without affecting the optical path. The deformed pupil mirror is designed to compensate for the following situations, such as astigmatism, cubic beam splitter, and rectangular phase retardation plate heating due to absorption, resulting in two-fold or four Four-fold wavefront deformation, as well as compaction effects.
本發明之一目的係提供一種反射折射投影物鏡,適合用於真空紫外範圍,具有勢能以提供非常高之像側數值孔徑,以及,長期穩定性之效能可被維持。It is an object of the present invention to provide a catadioptric projection objective suitable for use in the vacuum ultraviolet range, having potential energy to provide a very high image side numerical aperture, and long term stability performance can be maintained.
本發明之另一目的係提供投影物鏡以及曝光裝置組構來被操作於有穩定操作條件之照明設定,照明設定包括非傳統之離軸照明,例如雙極管或四極管照明。Another object of the present invention is to provide a projection objective and an exposure device assembly to be operated with illumination settings having stable operating conditions including non-conventional off-axis illumination, such as bipolar or quadrupole illumination.
本發明之另一目的係提供反射折射投影物鏡,為浸沒微影蝕刻提供穩定之光學效能。Another object of the present invention is to provide a catadioptric projection objective that provides stable optical performance for immersion lithography etching.
本發明之另一目的係為微影蝕刻應用提供反射折射投影物鏡,於低至193nm之波長,其可能以合理之成本而被製造,以及,其在於乾式微影蝕刻或浸沒微影蝕刻中,各種照明條件下,具有穩定之光學效能。Another object of the present invention is to provide a catadioptric projection objective for lithographic etching applications, which can be fabricated at a low cost to a wavelength of 193 nm, and which is in dry lithography or immersion lithography. Stable optical performance under a variety of lighting conditions.
做為本發明之以上目的之解決辦法,根據一構想,提供一種反射折射投影物鏡,將來自於一物場之一圖案成像於一像場,該物場係被設置於該投影物鏡之一物面中,該像場係被設置於該投影物鏡之一像面中,該反射折射投影物鏡包括:一第一物鏡部件,供來自該物面之該圖案成像為一第一中間影像,且該第一物鏡部件具有一第一光瞳面;一第二物鏡部件,供該第一中間影像成像為一第二中間影像,且該第二物鏡部件具有一第二光瞳面,與該第一光瞳面光學地共軛;一第三物鏡部件,供該第二中間影像成像於該像面,且該第三物鏡部件具有一第三光瞳面,與該第一光瞳面及該第二光瞳面光學地共軛;一光瞳鏡,具有一反射光瞳鏡表面,位於或接近於該第一光瞳面、該第二光瞳面與該第三光瞳面其中之一;以及一光瞳鏡操作器,可操作地連接於該光瞳鏡,供改變該光瞳鏡表面之形狀。In order to solve the above object of the present invention, according to an aspect, a catadioptric projection objective lens is provided for imaging a pattern from an object field to an image field, the object field being disposed on one of the projection objective lenses In the face, the image field is disposed in an image plane of the projection objective, the reflective and refractive projection objective comprises: a first objective lens component, wherein the pattern from the object surface is imaged as a first intermediate image, and the image is The first objective lens member has a first pupil face; a second objective lens member for imaging the first intermediate image as a second intermediate image, and the second objective lens member has a second pupil face, and the first The pupil plane is optically conjugated; a third objective lens component for imaging the second intermediate image on the image plane, and the third objective lens component has a third pupil plane, the first pupil plane and the first The two pupil planes are optically conjugated; a pupil mirror having a reflective pupil mirror surface located at or near the first pupil plane, the second pupil plane and the third pupil plane; And a light mirror operator operatively coupled to the aperture For changing the shape of the pupil mirror surface light.
於投影系統中,各種因時間變數且輻射導致之光學材料特徵之改變,於此申請案最開頭被提及到,導致之特徵成像像差很難以傳統之操作器進行補償;由於,對成像像差主要之因素係為對於非球面像差之場不變因素。更詳細地來說,軸上之像散性(AIDA)以及於場中四重之徑向對稱誤差(四波浪狀)常數可被觀察到。假設光瞳鏡具有光瞳鏡表面以及具有可改變此光瞳鏡反射表面之形狀的操作裝置,可補償這些像差,如此,實質上免於像差之一波前可於像面被獲得,即使對波前形狀之巨大干擾於投影物鏡中被產生,此等干擾係基於透鏡加熱或壓縮等。調整反射光瞳鏡表面之形狀可獲得校正,如此,因透鏡加熱或其他而產生之負向干擾可被光瞳鏡抵消。由於光瞳鏡係接近或位於投影物鏡之瞳表面,任何反射表面之形狀的形變或變化對所有場點實質上皆有相同的影響,其中實質上之場不變校正可被獲得。In projection systems, various changes in optical material characteristics due to time variations and radiation are mentioned at the very beginning of this application, resulting in characteristic imaging aberrations that are difficult to compensate with conventional operators; The main factor of the difference is the invariant factor for the aspheric aberration. In more detail, the on-axis astigmatism (AIDA) and the quadruple radial symmetry error (four wavy) constants in the field can be observed. Assuming that the pupil mirror has a pupil mirror surface and an operation device having a shape that can change the reflection surface of the pupil mirror, the aberration can be compensated, and thus, substantially one of the aberrations can be obtained from the image plane. Even if a large disturbance to the shape of the wavefront is generated in the projection objective, such interference is based on lens heating or compression. Correcting the shape of the surface of the reflected light mirror can be corrected so that negative interference due to lens heating or the like can be cancelled by the pupil mirror. Since the pupil mirror is close to or located on the pupil surface of the projection objective, the deformation or change in the shape of any reflective surface has substantially the same effect on all field points, wherein substantial field invariant correction can be obtained.
具有兩個真實的中間影像之反射折射投影物鏡可被設計於像場中獲取很高之像側數值孔徑,其足夠大而做為微影圖刻之應用,且不會產生漸暈之問題。進一步而言,離軸物場以及像端係被使用時,則在具有高像側數值孔徑之系統中,可避免瞳遮蔽。投影物鏡具有剛好三個連續物鏡部件,以及兩個之中間影像。第一物鏡部件至第三物鏡部件中之每一個物鏡部件係為成像之次系統,達成兩個連續的傅立葉轉換(2f-system),而且,沒有多餘之物鏡。當剛好兩個中間影像被提供時,大數量之自由角度被提供於光學系統中,其可以合裡之尺寸和複雜度被製造出來。於像端之大像側數值孔徑,做為微影之用途,係為可實行的。A catadioptric projection objective with two real intermediate images can be designed to obtain a very high image side numerical aperture in the image field, which is large enough to be used as a lithography and does not cause vignetting problems. Further, when the off-axis object field and the image end system are used, in a system having a high image side numerical aperture, 瞳 shielding can be avoided. The projection objective has exactly three consecutive objective components, as well as two intermediate images. Each of the first objective lens component to the third objective lens component is an imaging system that achieves two consecutive Fourier transforms (2f-system) and that there are no redundant objective lenses. When just two intermediate images are provided, a large number of free angles are provided in the optical system, which can be manufactured in a size and complexity. The numerical aperture on the large image side of the image end is useful as a lithography.
雖然光瞳鏡可能具有實質上平坦之反射表面,在大多數的實施例中,光瞳鏡係被設計為具有光學強度之光學元件。某些實施例中,光瞳鏡係為凹面鏡。While a pupil mirror may have a substantially flat reflective surface, in most embodiments, the pupil mirror is designed as an optical component having optical intensity. In some embodiments, the pupil mirror is a concave mirror.
介於物面與光瞳鏡之間所形成之至少一個中間影像是很有用的。其可在反射於光瞳鏡之前,適當地提供輻射。當至少一成像次系統(物鏡部件)置於物面及光瞳鏡之間,照射於光瞳鏡之輻射可有效地被準備來最佳化光瞳鏡之校正性能。At least one intermediate image formed between the object surface and the pupil mirror is useful. It can provide radiation appropriately before being reflected on the pupil mirror. When at least one imaging subsystem (objective component) is placed between the object surface and the pupil mirror, the radiation that is incident on the pupil mirror can be effectively prepared to optimize the correction performance of the pupil mirror.
某些實施例中,光瞳鏡被設置於第二物鏡部件之中,位於貨接近於第二瞳面。一或更多的透鏡可額外地被提供於第二物鏡部件之中,以形成反射折射之第二物鏡部件。選擇性地,第二物鏡部件可以是純反射。In some embodiments, the aperture mirror is disposed in the second objective lens component and is located adjacent to the second side of the surface. One or more lenses may additionally be provided in the second objective lens component to form a catadioptric second objective lens component. Alternatively, the second objective lens component can be purely reflective.
某些實施例中,形成第一中間影像之第一物鏡部件係為純折射,換言之,僅包含一或多個透鏡,而沒有成像面鏡。選擇性地,或額外地,將第二中間影像於像面上形成最終影像之第三物鏡部件,係為純折射物鏡部件。In some embodiments, the first objective lens component that forms the first intermediate image is purely refractive, in other words, contains only one or more lenses, and no imaging mirror. Optionally, or additionally, the third objective component forming the final image on the image surface of the second intermediate image is a pure refractive objective component.
串聯式系統依序包括第一折射物鏡部件(R),第二反射折射(或反射)物鏡部件(C),第三折射物鏡部件(R);此串聯式系統可被稱為”R-C-R”式系統。The tandem system sequentially includes a first refractive objective component (R), a second reflective refractive (or reflective) objective component (C), and a third refractive objective component (R); this tandem system may be referred to as "R-C" -R" system.
某些實施例中,第一物鏡部件係為反射折射物鏡部件,第二物鏡部件係為反射折射或反射的,且包含光瞳鏡;第三物鏡部件係為折射物鏡部件。這些系統可被稱為”C-C-R”式系統。In some embodiments, the first objective lens component is a catadioptric objective component, the second objective component is catadioptric or reflective, and includes a pupil mirror; and the third objective component is a refractive objective component. These systems may be referred to as "C-C-R" type systems.
投影物鏡之光學元件可依照各種不同方式來設置。The optical elements of the projection objective can be arranged in a variety of different ways.
某些實施例被設計為”折疊式”反射折射投影物鏡,其具有光軸,藉由面鏡(彎折面鏡),此光軸被至少兩個非平形之軸區間所切割。一般而言,彎折面鏡可具有平的反射面,也就是無光學強度。Some embodiments are designed as "folded" catadioptric projection objectives having an optical axis that is cut by at least two non-flat axis sections by a mirror (bending mirror). In general, a curved mirror can have a flat reflective surface, that is, no optical intensity.
某些實施例包含第一彎折面鏡,被設置以將來自該物面之輻射朝該光瞳鏡彎折,或,將來自該光瞳鏡之輻射朝像面彎折,如此,輻射以相反方向通過至少兩次之二次通過區域,幾何地被形成於該第一彎折鏡與該光瞳鏡之間。提供至少一彎折面鏡可更簡單地設置光瞳鏡接近或位於光瞳面,而不會過度地以光瞳鏡之大小而限制可使用之數值孔徑。Some embodiments include a first bending mirror configured to bend radiation from the object toward the pupil mirror, or to bend radiation from the pupil mirror toward the image plane, such that the radiation is The opposite direction is geometrically formed between the first bending mirror and the aperture mirror through at least two passes of the region. Providing at least one curved mirror makes it easier to set the aperture mirror close to or on the pupil plane without excessively limiting the usable numerical aperture by the size of the aperture mirror.
可提供與第一彎折面鏡具有90°夾角之第二彎折面鏡,如此物面以及像面相互平行。第二彎折面鏡可被設置來直接接收反射自光瞳鏡之輻射,或可被設置來接收反射自第一彎折面鏡之輻射。A second bending mirror having an angle of 90° with the first bending mirror may be provided, such that the object plane and the image plane are parallel to each other. The second curved mirror can be configured to directly receive radiation reflected from the aperture mirror or can be configured to receive radiation reflected from the first curved mirror.
某些實施例,第一彎折鏡被設置以將來自該物面之輻射朝該光瞳鏡之方向彎折,以及該第二重鏡被設置以將來自該光瞳鏡之輻射朝該像面之方向彎折。此折疊幾何可將光軸上之區塊設置成為實質上共軸,此等區塊係由第一物鏡部件以及第三物鏡部件之光學元件所界定,也就是說,精準之共軸或者僅有些微之橫向位移,關於傳統之透鏡直徑,此位移是非常小的。根據此一般性的折疊幾何,投影物鏡之例子被揭露於例如WO 2004/019128 A2,或者WO 2005/111689 A。此等文件之揭露內容係被併入本申請案作為參考。In some embodiments, the first bending mirror is configured to bend radiation from the object face toward the pupil mirror, and the second weight mirror is configured to direct radiation from the aperture mirror toward the image The direction of the face is bent. The folding geometry can set the blocks on the optical axis to be substantially coaxial, the blocks being defined by the optical elements of the first objective component and the third objective component, that is, accurate coaxial or only some The lateral displacement of the micro, this displacement is very small with respect to the conventional lens diameter. According to this general folding geometry, examples of projection objectives are disclosed, for example, in WO 2004/019128 A2, or WO 2005/111689 A. The disclosure of such documents is incorporated herein by reference.
在其他實施例中,第一彎折鏡被設置於該光瞳鏡之光學地下游的位置以將該光瞳鏡反射之輻射朝該第二彎折鏡彎折,以及,該第二彎折鏡被設置以將來自該第一彎折鏡之輻射朝該像面彎折。這些類型之實施利中,被凹光瞳鏡定義之光軸可與被第一物鏡部件定義之光軸區塊共軸。物面與像面之間的大的橫向位移一般而言可被取得,相較於傳統之透鏡直鏡,此位移較大。此種類型之物鏡一般而言包含兩個透鏡筒結構,相互平行地設置。代表性之舉例被揭露,例如於美國專利US 6,995,833 B2中。以上文件之揭露內容係被併入本申請案作為參考。In other embodiments, the first bending mirror is disposed at an optically downstream position of the aperture mirror to bend the radiation reflected by the aperture mirror toward the second bending mirror, and the second bending A mirror is provided to bend radiation from the first bending mirror toward the image plane. In these types of implementations, the optical axis defined by the concave aperture mirror can be coaxial with the optical axis block defined by the first objective component. The large lateral displacement between the object surface and the image plane can generally be obtained, which is larger than the conventional lens straight mirror. Objective lenses of this type generally comprise two lens barrel structures arranged parallel to one another. Representative examples are disclosed, for example, in U.S. Patent No. 6,995,833 B2. The disclosure of the above documents is incorporated herein by reference.
包含至少一負鏡之負鏡組可被設置於一該凹光瞳面鏡之反射端之前且在一個二次通過區域,如此輻射以反方向通過該負鏡兩次。負鏡組可被置鄰近於接近瞳之區域的凹光瞳鏡之位置,接近瞳之區域之特徵為成像之邊緣光束高度(MRH)大於主要光束高度(CRH)。較佳地,邊緣光束高度至少為於負鏡組中之主要光束高度的兩倍大,甚至,至少五到十倍大。位於具有大邊緣光束高度之區域的負鏡組可有效提供色差校正,特別是校正軸向色差,由於薄透鏡之軸向色差係與邊緣光束高度的平方成正比,邊緣光束高度係於透鏡之位置(以及,與折射強度以及透鏡消散成正比)。加諸於此的是投影之輻射以反方向通過該負鏡組兩次,負鏡組係位於直接鄰近於凹面鏡之處,可使負鏡組之色差過度校正效應被利用兩次。負鏡組可包含單一負鏡或至少兩負鏡。A negative mirror group including at least one negative mirror may be disposed before a reflective end of the concave aperture mirror and in a secondary pass region such that the radiation passes through the negative mirror twice in the reverse direction. The negative mirror group can be placed adjacent to the concave aperture mirror near the pupil region, and the region near the pupil is characterized by an imaged edge beam height (MRH) greater than the primary beam height (CRH). Preferably, the edge beam height is at least twice as large as the main beam height in the negative mirror group, or even at least five to ten times larger. A negative lens group located in a region with a large edge beam height can effectively provide chromatic aberration correction, especially for correcting axial chromatic aberration. Since the axial chromatic aberration of the thin lens is proportional to the square of the height of the edge beam, the edge beam height is at the position of the lens. (And, proportional to the intensity of the refraction and the dissipation of the lens). Addition thereto is that the projected radiation passes through the negative mirror twice in the opposite direction, and the negative mirror group is located directly adjacent to the concave mirror, so that the chromatic aberration overcorrecting effect of the negative mirror group can be utilized twice. The negative mirror group can comprise a single negative mirror or at least two negative mirrors.
某些實施例中,投影物鏡中所有的光學元件係沿筆直的光軸排列。此類型之光學系統可被稱為「線內系統」。In some embodiments, all of the optical elements in the projection objective are arranged along a straight optical axis. This type of optical system can be referred to as an "inline system."
自光學的角度來看,線內系統是較佳的,由於因利用平面折疊鏡所造成之光學問題,例如極性效應,可被避免。另外,以製造的觀點來看,線內系統可被設計使得光學元件的傳統裝設技術可被利用,如此改善投影物鏡之機構穩定度。利用雙數面鏡,例如二或四或六個面鏡,可使成像不會產生影像跳動。From an optical point of view, an in-line system is preferred because optical problems such as polarity effects due to the use of planar folding mirrors can be avoided. In addition, from a manufacturing point of view, the in-line system can be designed such that conventional mounting techniques for optical components can be utilized, thus improving the mechanical stability of the projection objective. With a double mirror, such as two or four or six mirrors, imaging can be prevented from image bounce.
線內系統之光學元件可包含一鏡組,其具有物端鏡組入口用來接收來自該物面之輻射,以及具有像端鏡組出口用來將來自該鏡組出口並朝該像面之輻射射出,其中該鏡組包括至少一光瞳鏡。The optical component of the in-line system can include a mirror assembly having an object end mirror inlet for receiving radiation from the object surface and having an end mirror assembly outlet for exiting the mirror assembly from the image surface Radiation is emitted, wherein the mirror assembly includes at least one aperture mirror.
當欲求一軸上場(物場和像場以光軸為中心),則鏡組可由一對凹面鏡所組成,此對凹面鏡包含相面對之凹反射面,而透明之部分(例如洞或孔)係由位於光軸附近之鏡表面所製造,其可使輻射通過面鏡。凹面鏡可被設置於光學上接近光瞳表面之處。至少一凹面鏡可被提供光瞳鏡操作器以形成可形變光瞳鏡。具有兩個中間影像,軸上場,以及瞳遮蔽之系統被揭露於如申請人之美國專利US 6,600,608,其揭露內容被併入本申請案作為參考。When an on-axis field is desired (the object field and the image field are centered on the optical axis), the mirror group may be composed of a pair of concave mirrors, the concave mirrors comprising facing concave reflecting surfaces, and the transparent portions (such as holes or holes) Manufactured by a mirror surface located near the optical axis that allows radiation to pass through the mirror. A concave mirror can be placed optically near the surface of the pupil. At least one concave mirror can be provided with a pupil mirror operator to form a deformable aperture mirror. A system having two intermediate images, an on-axis field, and a shadow mask is disclosed in U.S. Patent No. 6,600,608, the disclosure of which is incorporated herein by reference.
欲求不具瞳遮蔽之成像,則離軸場(像場和物場完全位於光軸之外)可被使用。For imaging without obscuration, the off-axis field (image field and object field are completely outside the optical axis) can be used.
線內系統一般而言僅有非常小的安裝空間來放置面鏡。另外,於光瞳表面之面鏡之尺寸,限制於大像側數值孔徑成像合理尺寸之矩形或拱形的「有效像場」之能力。此對應於物場之相對低的「有效光展量」(有效幾何通量),也就是說,成像無漸暈之最內端場點與有效誤場之外緣之距離是很小的。於此等條件下,「設計物場」之尺寸,也就是投影物鏡可被充分校正之場,可變成相對大,假設欲得到具有矩形或拱形且為合理尺寸的「有效像場」。假若設計物場之尺寸增加,則光學元件之尺寸與數量會大幅的增加,一般來說,希望將設計物場保持越小越好。(有效物場、設計物場之有效光展量以及此兩者的相互關係的詳細定義可見欲申請人之國際專利申請案WO 2005/098506 A1,揭露內容被併入本申請案作為參考)In-line systems generally have only a very small installation space for the mirror. In addition, the size of the mirror on the surface of the pupil is limited to the ability of the large image side numerical aperture to image a rectangular or arched "effective image field" of a reasonable size. This corresponds to the relatively low "effective light spread" (effective geometric flux) of the object field, that is, the distance between the innermost field point of the imaging without vignetting and the outer edge of the effective misfield is small. Under these conditions, the size of the "design object", that is, the field where the projection objective can be sufficiently corrected, can become relatively large, assuming that an "effective image field" having a rectangular or arch shape and a reasonable size is desired. If the size of the design object is increased, the size and number of optical components will increase significantly. Generally, it is desirable to keep the design object as small as possible. (The effective object field, the effective light spread of the design object field, and the detailed definition of the relationship between the two can be found in the International Patent Application No. WO 2005/098506 A1, the disclosure of which is incorporated herein by reference.
就以上考量,鏡組包含:第一鏡片,用來接收來自該鏡組入口之輻射於一第一反射區域;第二鏡片,用來接收來自該第一鏡片之輻射於一第二反射區域;第三鏡片,用來接收反射自該第二鏡片之輻射於一第三反射區域;以及第四鏡片,用來接收反射自該第三鏡片之輻射,以及用來將該輻射反射至該鏡組出口;其中至少兩個該等鏡片係為凹面鏡,具有一曲面旋轉地對稱於該光軸。For the above considerations, the lens set includes: a first lens for receiving radiation from the entrance of the lens group in a first reflective area; and a second lens for receiving radiation from the first lens to a second reflective area; a third lens for receiving radiation reflected from the second lens in a third reflective area; and a fourth lens for receiving radiation reflected from the third lens and for reflecting the radiation to the lens group An outlet; wherein at least two of the lenses are concave mirrors having a curved surface that is rotationally symmetric with respect to the optical axis.
即使像側數值孔徑增加,鏡組中包含至少四個面鏡可限制光瞳鏡之尺寸,如此漸暈控制更容易被達成。較佳地,恰好四個面鏡被提供。鏡組中之所有面鏡可為凹面鏡。Even if the image side numerical aperture is increased, the inclusion of at least four mirrors in the lens group limits the size of the pupil mirror, so that vignetting control is more easily achieved. Preferably, exactly four mirrors are provided. All mirrors in the mirror group can be concave mirrors.
雖然可能利用第二鏡片(幾何地較接近於物面)做為光瞳鏡,若第三鏡片被架構為光瞳鏡是很有用的。第三鏡片,一般而言,於鏡組之像端,在幾何地與物面相距很遠,如此可提供幾何空間,以適當地導引輻射朝向第三鏡片。另外,光學上行至第三鏡片,且包含第一和第二鏡片之光學元件可被用來為光瞳鏡成形與準備輻射光束。舉例而言,若必要,校正狀態以及主要光束高度可被影響。Although it is possible to use the second lens (geometrically closer to the object surface) as the pupil mirror, it is useful if the third lens is constructed as a pupil mirror. The third lens, in general, is geometrically spaced from the object surface at the image end of the mirror so as to provide a geometrical space to properly direct the radiation toward the third lens. Additionally, optically up to the third lens, and the optical elements comprising the first and second lenses can be used to shape and prepare the radiation beam for the pupil. For example, the correction state and the main beam height can be affected if necessary.
較佳地,鏡組之面鏡被設置以使來自鏡組入口之輻射通過鏡組平面至少五次,鏡組平面被定義為橫切於光軸且在幾何地被設置介於鏡組入口與鏡組出口之間,在輻射由鏡組出口射出鏡組之前。許多之至少四次反射由此可被獲得,在軸向壓縮之空間中,此空間係被定義介於鏡組入口以及鏡組出口之間。Preferably, the mirror of the mirror is arranged such that the radiation from the entrance of the mirror passes through the plane of the mirror at least five times, the plane of the mirror being defined transverse to the optical axis and geometrically placed between the entrance of the mirror and Between the exits of the mirror group, before the radiation is emitted from the exit of the mirror group. A plurality of at least four reflections can thus be obtained, and in the space of axial compression, this space is defined between the mirror set entrance and the mirror set exit.
前端透鏡組可被設置介於物面以及鏡組入口之間,如此可將於物面之輻射的空間分佈轉換成為所欲求之於鏡組入口之輻射的角度分佈,以及,可調整入射角度,此輻射進入鏡組且照射於第一鏡片。前端透鏡組之設計可被選擇,如此,進入鏡組入口之輻射,具有欲求之橫截面形狀,可使輻射光束通過鏡組入口而不需觸碰到鄰近的面鏡邊緣,如此可避免光束漸暈。前端透鏡組可被設計為傅立葉透鏡組,也就是,能達成單一傅立葉轉換之單一光學元件或包含至少兩個光學元件的光學組,或者,介於前端焦點平面以及後端焦點平面之間的單數之連續傅立葉轉換。較佳實施例中,形成前端透鏡組之傅立葉透鏡組可被設定來對投影物鏡之瞳入口實質上成像於鏡組入口之位置,如此有一光瞳面位於或接近於鏡組入口。也可能有不具有前端透鏡組之實施例。The front lens group can be disposed between the object surface and the entrance of the lens group, so that the spatial distribution of the radiation of the object surface can be converted into the angular distribution of the radiation desired at the entrance of the lens group, and the incident angle can be adjusted. This radiation enters the mirror and illuminates the first lens. The design of the front lens group can be selected such that the radiation entering the entrance of the lens group has a desired cross-sectional shape, allowing the radiation beam to pass through the entrance of the lens group without touching the edge of the adjacent mirror, thus avoiding the beam. gosh. The front lens group can be designed as a Fourier lens group, that is, a single optical element capable of achieving a single Fourier transform or an optical group comprising at least two optical elements, or a singularity between a front end focus plane and a back end focus plane Continuous Fourier transform. In a preferred embodiment, the Fourier lens group forming the front lens group can be set to substantially image the entrance of the projection objective at the entrance of the lens assembly such that a pupil plane is at or near the entrance of the lens assembly. There may also be embodiments without a front lens group.
具有壓縮四面鏡之鏡組的反射折射線內系統被揭露於申請人之國際專利申請案WO 2005/098505 A1,揭露內容被併入本申請案作為參考。某些實施例包括光瞳鏡且在適當的調整下與本發明有關。A system of refracting in-line with a mirror of a four-sided mirror is disclosed in the applicant's International Patent Application No. WO 2005/098505 A1, the disclosure of which is incorporated herein by reference. Some embodiments include a light pupil mirror and are related to the present invention with appropriate adjustments.
某些實施例中第一物鏡部件(形成一中間影像下行至光瞳鏡)被設計為放大成像系統,具有放大率|β|>1,如此所形成之第一中間影像係大於有效物場。較佳地,維持|β|>1.5之條件。放大的中間影像可被利用來獲得大的主要光束角度CRAPM 位於下行之光瞳鏡。考慮到於光學成像系統中,平行軸的主要光束角度CRA的產出以及瞳尺寸係為常數(拉格朗不變量),於光瞳面之大的主要光束角度對應於小的瞳,也就是對應至位於光瞳面之光束的小光束直徑。某些實施例中,光瞳鏡被安置於該光瞳鏡上游的一第一鏡片與該光瞳鏡下游的一第二鏡片之間的位置,而物面之一主要光束高度係為CRHO ,在該第一鏡片之一主要光束高度係為CRH1 ,以及,在該第二鏡片之一主要光束高度係為CRH2 ,其中,CRH1 >CRH0 以及CRH2 >CRH0 之條件被滿足。較佳地,CRH1 >1.5*CRH0 以及CRH2 >CRH0 之條件至少其一被滿足。換言之,立即上行及下行至光瞳鏡之面鏡的主要光束高度係大於物高。光學上上行或下行至該光瞳鏡之該等面鏡至少其一之主要光束高度以及於該物面之該主要光束高度CRHO 之比值至少為1.5,或至少為2.0,或至少為2.5。在這些情況下,在光瞳鏡可獲得小的光束直徑,其可允許小尺寸之光瞳鏡。In some embodiments, the first objective lens component (forming an intermediate image down to the pupil mirror) is designed to magnify the imaging system with magnification |β|>1 such that the first intermediate image system formed is larger than the effective object field. Preferably, the condition of |β| > 1.5 is maintained. The magnified intermediate image can be utilized to obtain a large primary beam angle CRA PM located downstream of the pupil. Considering that in the optical imaging system, the output of the main beam angle CRA of the parallel axis and the 瞳 size are constant (Lagrangian invariant), the main beam angle at the pupil plane corresponds to a small 瞳, that is, Corresponds to the small beam diameter of the beam at the pupil plane. In some embodiments, the aperture mirror is disposed between a first lens upstream of the aperture mirror and a second lens downstream of the aperture mirror, and one of the primary beam heights of the object plane is CRH O The primary beam height of one of the first lenses is CRH 1 , and the primary beam height of one of the second lenses is CRH 2 , wherein the conditions of CRH 1 >CRH 0 and CRH 2 >CRH 0 are satisfied. . Preferably, at least one of the conditions of CRH 1 >1.5*CRH 0 and CRH 2 >CRH 0 is satisfied. In other words, the main beam height of the mirror that immediately goes up and down to the pupil mirror is greater than the object height. The mirrors optically up or down to the pupil mirror have a ratio of at least one of the primary beam heights to the primary beam height CRH O of the object plane of at least 1.5, or at least 2.0, or at least 2.5. In these cases, a small beam diameter is obtained in the pupil mirror, which allows for a small-sized pupil lens.
某些實施例中,被設置於物面以及光瞳鏡之間的光學元件被設定在該光瞳鏡提供最大主要光束角度CRAMAX >25°。某些實施例中,大於30°或大於35°或甚至大於40°之最大主要光束角度都是有可能的。小的瞳可使光瞳鏡具有小的直徑。此可導引輻射通過光瞳鏡,即使投影光束之輻射有很大的孔徑。因此,光瞳鏡上大的主要光束角度,可在反射折射線內系統中更容易獲得高的像側數值孔徑。In some embodiments, an optical element disposed between the object surface and the pupil mirror is configured to provide a maximum primary beam angle CRA MAX > 25° to the aperture mirror. In some embodiments, a maximum primary beam angle greater than 30° or greater than 35° or even greater than 40° is possible. A small flaw can give the pupil mirror a small diameter. This directs the radiation through the pupil mirror even if the projection beam has a large aperture. Therefore, the large main beam angle on the pupil mirror makes it easier to obtain a high image side numerical aperture in a system of reflection and refraction lines.
光學上被使用之光瞳鏡自由直徑DPM 可特別的小。某些實施例中,在整個投影物鏡中,光瞳鏡係為具有最小直徑之光學元件。光瞳鏡直徑DPM 可比投影物鏡中之光學元件的最大自由直徑少50%,或少40%或30%。The optical aperture mirror free diameter D PM that is optically used can be particularly small. In some embodiments, the optical mirror is the optical element having the smallest diameter throughout the projection objective. The pupil diameter D PM can be 50% less, or 40% or 30% less than the maximum free diameter of the optical elements in the projection objective.
投影物鏡可具有孔徑光闌,以允許調整為所欲求之孔徑之直徑,其中孔徑光闌之最大孔徑直徑至少是光瞳鏡直徑DPM 的兩倍大。The projection objective may have an aperture stop to allow adjustment to the diameter of the desired aperture, wherein the aperture aperture has a maximum aperture diameter that is at least twice as large as the pupil diameter DPM .
光瞳鏡表面之形變係用來影響校正,此校正對所有的場點實質相同(也就是被稱為場不變校正)。應特別強調之處為入射於光瞳鏡之投影光束的校正狀態。較佳的,光瞳鏡之投影光束遵循以下條件:| CRHi |/D0 <0.1 (1) 0.9=<Di /D0 =<1.1 (2)其中| CRHi |係為該光瞳鏡表面之一物場點i中一主要光束之一主要光束高度的數量值;D0 係為於該光瞳鏡表面之一邊緣光束高度的數量值得兩倍;以及Di =| HRRUi -HRRLi |係為,於該光瞳鏡表面之一場點i,該投影物鏡中一光瞳入口之一影像子午線方向之一直徑,其中,HRRUi 係為一上邊緣光束之該邊緣光束高度,以及HRRLi 係為一下邊緣光束之該邊緣光束高度,對應於該場點i。The deformation of the pupil mirror surface is used to influence the correction, which is substantially the same for all field points (also known as field invariant correction). Special emphasis should be placed on the corrected state of the projected beam incident on the pupil mirror. Preferably, the projection beam of the pupil mirror follows the following condition: | CRH i |/D 0 <0.1 (1) 0.9=<D i /D 0 =<1.1 (2) wherein |CRH i | is the pupil One of the main beam heights of one of the main beams in the object field i of the mirror surface; D 0 is twice the number of beam heights at one edge of the pupil mirror surface; and D i =| HRRU i - HRRL i | is a field point i on the surface of the pupil mirror, a diameter of one of the meridian directions of one of the pupil entrances in the projection objective lens, wherein the HRRU i is the edge beam height of an upper edge beam, And the HRRL i is the edge beam height of the lower edge beam, corresponding to the field point i.
主要光束係指自最外端之場點行進至瞳入口之中心的光束。假設以上的條件(1)與(2)被滿足,則瞳入口之影像係非常接近或位於光瞳鏡,其回應於光瞳鏡之形變,可獲得場不變校正(field-constant correction)。The primary beam is the beam that travels from the outermost field point to the center of the entrance. Assuming that the above conditions (1) and (2) are satisfied, the image of the entrance is very close to or located in the pupil mirror, which responds to the deformation of the pupil mirror to obtain a field-constant correction.
欲求軸向壓縮設計之某些實施例可能要求具有相同反射方向之光瞳鏡以及其他面鏡應幾何地被設置成互相靠近。某些實施例中,此問題可藉由提供一對面鏡而被解決。此對面鏡包含兩個凹面鏡,此兩凹面鏡具有相同曲面之鏡表面,此相同曲面係被提供於共同之基板上,此兩凹面鏡其中之一係為該光瞳鏡,具有反射光瞳鏡表面,被設定可由光瞳鏡操作器形變,以及另一凹面鏡具有與該光瞳鏡表面分開之折射表面。此鏡組合可被提供於相同設置之結構,如此可使光瞳鏡之設置更加容易。Certain embodiments of the axial compression design may require that the aperture mirrors and other mirrors having the same direction of reflection be geometrically placed close to each other. In some embodiments, this problem can be solved by providing a pair of mirrors. The pair of mirrors comprises two concave mirrors having mirror surfaces of the same curved surface, the same curved surface being provided on a common substrate, one of the two concave mirrors being the light pupil mirror having a reflective light mirror surface. It is set to be deformable by the pupil mirror operator, and the other concave mirror has a refractive surface separate from the pupil mirror surface. This mirror combination can be provided in the same configuration, which makes the setting of the pupil mirror easier.
某些實施例中,光瞳鏡被設置位於或接近於光瞳表面的其中之一,且一或多的透明光學元件被設置位於或接近於至少一光學地共軛之光瞳表面。一般而言,位於或接近於光瞳表面之位置係指邊緣光束高度MRH大於主要光束高度CRH之位置,如此光束高度比RHR=MRH/CRH>1。吸收所導致之形變,以及於透鏡元件中所造成之折射係數的變化(接近於共軛之光瞳表面)可造成波前像差,其可以適當地形變光瞳鏡表面而被補償。舉例而言,假若極性照明設定,例如雙極或四極性照明被使用,則分別具有二重或四重徑向對稱之非均質輻射負載可使透明光學元件接近於光瞳表面。具有二重或四重徑向對稱之導致之波前形變,可至少部分被補償,藉由對應之光瞳鏡表面形變,此形變係透過以二重或四重之徑向對稱以形變光瞳鏡表面。In some embodiments, the pupil mirror is disposed at or near one of the pupil surfaces, and one or more transparent optical elements are disposed at or near at least one optically conjugated pupil surface. In general, the position at or near the surface of the pupil refers to the position at which the edge beam height MRH is greater than the main beam height CRH such that the beam height ratio RHR = MRH / CRH > 1. The deformation caused by absorption, as well as the change in the refractive index (close to the conjugated pupil surface) caused in the lens element, can cause wavefront aberrations, which can be compensated by appropriately morphing the light-mirror surface. For example, if a polar illumination setting, such as bipolar or quadrupole illumination, is used, a non-homogeneous radiation load having a double or quadruple radial symmetry, respectively, can bring the transparent optical element close to the pupil surface. The wavefront deformation caused by the double or quadruple radial symmetry can be at least partially compensated by the deformation of the surface of the corresponding pupil mirror, which is transmitted through the radial symmetry of the double or quadruple to deform the aperture Mirror surface.
由位於光瞳鏡之操作器所提供之補償能力在某些光學系統中特別有用,此等光學系統係使用某些光學材質,其對不均勻之吸收導致之熱效應特別敏感。舉例而言,可能需由熔凝矽土(合成石英玻璃)去製造某些或全部之透鏡。熔凝矽土(fused silica)可有高光學品質且在質量及尺寸上皆足夠大以製造大的透鏡,例如要求有高NA之微影蝕刻的投影物鏡。進一步而言,處理熔凝矽土以獲得高品質之光學表面是已被達成的技術。另外,熔凝矽土,實際上,對低至約190nm之波長,仍具有無吸收性。因此,可能需要大量的熔凝矽土做為物鏡之透鏡。另一方面來說,熔凝矽土的特徵熱傳導係小於鈣氟化物(CaF2 )的特徵熱傳導與其他鹼性之氟化物晶體材料,此等氟化物被使用於更短的波長,例如157nm,其係由於甚至在這些短波長時仍具有非常低的吸收。由於鈣氟化物(CaF2 )的特徵熱傳導大於熔凝矽土的特徵熱傳導,在鈣氟化物中投影光束之不均勻加熱的負面效應係小於熔凝矽土,基於在相對高的特徵熱傳導之材料中,由不均勻加熱所造成之局部溫度可更快且更有效率的達到平衡。因此使得由此等材料所製成之系統不易受不均勻透鏡加熱所造成之問題的影響。可被操作來補償透鏡加熱效應的光瞳面鏡允許使用如熔凝矽土,即使位於或接近於共軛光瞳表面,此處非常容易產生不均勻透鏡加熱之問題,當在某一照明狀況之下,或在使用某種圖案架構之下。The compensation capabilities provided by the manipulators located in the pupil mirrors are particularly useful in certain optical systems that use certain optical materials that are particularly sensitive to thermal effects caused by uneven absorption. For example, it may be desirable to make some or all of the lenses from fused alumina (synthetic quartz glass). Fused silica can be of high optical quality and large enough in both mass and size to produce large lenses, such as projection objectives requiring high NA lithographic etching. Further, processing fused alumina to obtain a high quality optical surface is a technique that has been achieved. In addition, fused alumina, in fact, still has no absorption for wavelengths as low as about 190 nm. Therefore, a large amount of fused alumina may be required as a lens of the objective lens. On the other hand, the characteristic heat conduction of fused alumina is less than the characteristic heat conduction of calcium fluoride (CaF 2 ) and other basic fluoride crystal materials, and such fluorides are used at shorter wavelengths, such as 157 nm. It is due to the very low absorption even at these short wavelengths. Since the characteristic heat conduction of calcium fluoride (CaF 2 ) is greater than the characteristic heat conduction of fused alumina, the negative effect of uneven heating of the projection beam in calcium fluoride is less than that of fused alumina, based on materials with relatively high characteristic heat conduction. The local temperature caused by uneven heating can reach equilibrium faster and more efficiently. Therefore, the system made of such materials is less susceptible to the problems caused by the heating of the uneven lens. A pupil mirror that can be manipulated to compensate for lens heating effects allows the use of, for example, fused alumina, even at or near the surface of the conjugate aperture, where the problem of uneven lens heating is very likely to occur when in certain lighting conditions Under, or under the use of a certain pattern architecture.
某些實施例中,位於或接近於光學地共軛之光瞳表面的光學元件係由具有特徵熱傳導之光學材料所製成,其特徵熱傳導係小於鈣氟化物之特徵熱傳導。例如,位於或接近於共軛光瞳表面之光學元件可由熔凝矽土所製成。In some embodiments, the optical element at or near the optically conjugated pupil surface is made of an optical material having characteristic heat conduction, the characteristic heat conduction of which is less than the characteristic heat conduction of the calcium fluoride. For example, an optical element located at or near the surface of the conjugate aperture can be made of fused alumina.
某些實施例中,投影物鏡中至少90%的透鏡皆由熔凝矽土所製成。某些實施例中,所有的透鏡皆由熔凝矽土所製成。In some embodiments, at least 90% of the lenses in the projection objective are made of fused alumina. In some embodiments, all of the lenses are made of fused alumina.
實施例中可能具有例如像側數值孔徑NA>=0.6,如此可用於微影蝕刻中以在微影蝕刻曝光製成中獲得小尺寸。也可能有具有NA>=0.7之實施例。某些實施例中反射折射投影物鏡具有像側數值孔徑NA>=0.8,或甚至NA>=0.9,其係接近於理論上對乾式系統的限制,也就是說,調適於成像像差且用於乾式製程之投影物鏡,其中介於投影物鏡之出口表面以及像面之間的影像空間係填充具有折射係數接近於1之氣體。It is possible in embodiments to have, for example, an image side numerical aperture NA >= 0.6, which can be used in lithography etching to achieve a small size in lithographic etch exposure fabrication. There may also be embodiments with NA >=0.7. In some embodiments, the catadioptric projection objective has an image side numerical aperture NA >= 0.8, or even NA >= 0.9, which is close to the theoretical limit to the dry system, that is, the modulation is suitable for imaging aberrations and is used for A dry process projection objective in which an image space between the exit surface of the projection objective and the image plane is filled with a gas having a refractive index close to one.
其他實施例中,反射折射投影物鏡被設計為浸沒物鏡,調適於有關成像差之一濕式過程,其介於該投影物鏡之出口表面與該像面之間之該影像空間係充滿具有折射係數遠大於1之浸沒介質。舉例而言,折射係數可能為1.3或更大,或者為1.4或更大,或者為1.5或更大。投影物鏡具有一像側數值孔徑NA>1.0,當該投影物鏡被使用於具有折射係數nI >1.3之浸沒介質中,例如NA>=1.1或者NA>=1.2或者NA>=1.3。選擇性的,投影物鏡可具有像側數值孔徑NA<1.0,當被使用於浸沒介質中。In other embodiments, the catadioptric projection objective is designed as an immersion objective, adapted to a wet process associated with imaging differences, the image space between the exit surface of the projection objective and the image surface being filled with a refractive index Immersion medium much larger than 1. For example, the refractive index may be 1.3 or greater, or 1.4 or greater, or 1.5 or greater. The projection objective has an image side numerical aperture NA > 1.0, when the projection objective is used in an immersion medium having a refractive index n I > 1.3, such as NA >=1.1 or NA >=1.2 or NA >=1.3. Alternatively, the projection objective can have an image side numerical aperture NA < 1.0 when used in an immersion medium.
一般而言,像側數值孔徑NA係被成像空間中周圍的介質的折射係數所限制。在浸沒微影中,理論上可行的像側數值孔徑NA系被浸沒介質的折射係數所限制。浸沒介質可以是液體(液體浸沒,濕式製程)或者是固體(固體浸沒)。In general, the image side numerical aperture NA is limited by the refractive index of the surrounding medium in the imaging space. In immersion lithography, the theoretically feasible image side numerical aperture NA is limited by the refractive index of the immersion medium. The immersion medium can be a liquid (liquid immersion, wet process) or a solid (solid immersion).
實際而言,孔徑不應任意地接近於最後介質的折射係數,最後介質也就是最接近於像的介質;其係由於前進角度相對於光軸會變得很大。就經驗而言,於像端,像側數值孔徑NA可達到最後介質之折射係數的95%。以193nm之浸沒微影來說,以水(nH20 =1.43)做為浸沒介質的例子中,此對應之數值孔徑NA=1.35。In practice, the aperture should not be arbitrarily close to the refractive index of the final medium, and finally the medium is the medium closest to the image; it is because the angle of advancement becomes large relative to the optical axis. As far as experience is concerned, at the image end, the image side numerical aperture NA can reach 95% of the refractive index of the final medium. In the case of immersion lithography at 193 nm, in the case of water (n H20 = 1.43) as the immersion medium, the corresponding numerical aperture NA = 1.35.
某些實施例被設定來允許沿伸像側數值孔徑NA至NA=1.35或更高。某些實施例中至少一個光學元件係為高係數的光學元件,其係由高係數且於操作波長之折射係數n>=1.6的材料所製成。此折射係數在操作波長中,可約為1.7或更多,或為1.8或更多,或甚至為1.9或更多。操作波長可為低於260nm之深紫外線(DUV),例如248nm或193nm。Some embodiments are set to allow numerical aperture NA to NA = 1.35 or higher along the image side. In some embodiments at least one optical component is a high coefficient optical component made of a material having a high coefficient and a refractive index n >= 1.6 at the operating wavelength. This refractive index may be about 1.7 or more, or 1.8 or more, or even 1.9 or more in the operating wavelength. The operating wavelength can be deep ultraviolet (DUV) below 260 nm, such as 248 nm or 193 nm.
投影物鏡具有最接近於像面之最後光學元件。最後光學元件之出口端立即鄰近於像面,此出口端形成投影物鏡之出口表面。出口表面可以是平面或曲面,例如凹陷。某些實施例中,最後光學元件係至少部分由高係數且於操作波長具有折射係數n>1.6之材料所製成。舉例而言,最後光學元件整體可為平凸透鏡,其具有球面或非球面之彎曲之入口表面,且有平坦的出口表面立即鄰近於像面。The projection objective has the last optical element closest to the image plane. Finally, the exit end of the optical element is immediately adjacent to the image plane, which exit surface forms the exit surface of the projection objective. The exit surface can be a flat or curved surface, such as a recess. In some embodiments, the final optical component is made, at least in part, of a material having a high coefficient and having a refractive index n > 1.6 at the operating wavelength. For example, the final optical element as a whole may be a plano-convex lens having a spherical or aspheric curved entrance surface with a flat exit surface immediately adjacent to the image surface.
高係數材料可例如為氧化鋁(Al2 O3 ),其可被用作高係數材料而操作波長低至193nm。某些實施例中,高係數材料為鎦化鋁石榴石(LuAG),於193nm具有折射係數n=2.14。高係數材料可為鋇氟化物(BaF2 ),鋰氟化物(LiF),以及鋇鋰氟化物(BaLiF3 )。折射係數高於水之浸沒液體可被使用,例如在水中摻雜使係數增加之添加物,或者於193nm有nI =1.65之環已烷。某些實施例中,於λ=193nm,像側數值孔徑NA>1.4以及NA>1.5可被獲得,例如NA=1.55。使用高係數之材料於反射折射投影物鏡做為浸沒微影被揭露於例如申請人之美國專利申請案號11/151,465。上述揭露內容係被併入本申請案作為參考。The high coefficient material can be, for example, alumina (Al 2 O 3 ), which can be used as a high coefficient material with operating wavelengths as low as 193 nm. In some embodiments, the high coefficient material is aluminum telluride garnet (LuAG) having a refractive index n = 2.14 at 193 nm. The high coefficient material may be barium fluoride (BaF 2 ), lithium fluoride (LiF), and barium lithium fluoride (BaLiF 3 ). An immersion liquid having a higher refractive index than water can be used, for example, an additive in which water is doped to increase the coefficient, or a cyclohexane having n I = 1.65 at 193 nm. In some embodiments, at λ = 193 nm, the image side numerical aperture NA > 1.4 and NA > 1.5 can be obtained, for example, NA = 1.55. The use of a high coefficient of material in a catadioptric projection objective as an immersion lithography is disclosed, for example, in the applicant's U.S. Patent Application Serial No. 11/151,465. The above disclosure is incorporated herein by reference.
發明提供之反射折射投影物鏡具有適當的大小以進行浸沒微影,特別是於像側數值孔徑NA>1。投影物鏡之成像特徵可於投影物鏡之生命週期中動態地被調整,藉由調整反射光瞳鏡表面之形狀來達成。當觀察出某些有關於投影光束於光瞳鏡之校正狀態之狀況,則實質上在整個場中為常數(些微或無改變)之校正效應(場不變校正)可被獲得。於浸沒系統中,這些特性可被用來補償成像誤差,其係由隨時間產生之浸沒液體光學特性的改變而造成,例如其可由溫度之改變而造成。舉例而言,場不變貢獻於因浸沒層溫度漂移而產生球面誤差可被補償,此浸沒層係處於實質上晶圓中之遠心影像。The catadioptric projection objective provided by the invention has an appropriate size for immersion lithography, particularly with an image side numerical aperture NA > The imaging features of the projection objective can be dynamically adjusted during the life cycle of the projection objective by adjusting the shape of the reflective pupil mirror surface. When some conditions relating to the corrected state of the projected beam to the pupil mirror are observed, a correction effect (field invariant correction) that is substantially constant (slightly or no change) throughout the field can be obtained. In immersion systems, these characteristics can be used to compensate for imaging errors caused by changes in the optical properties of the immersion liquid that are produced over time, for example, which can be caused by changes in temperature. For example, a field invariant contribution to spherical aberration due to immersion layer temperature drift can be compensated for, and the immersion layer is in a substantially telecentric image in the wafer.
補償之利用與投影物鏡之種類無關(例如,具有或沒有中間影像,線內或折疊式投影物鏡)。The use of compensation is independent of the type of projection objective (eg, with or without intermediate images, in-line or folded projection objectives).
根據另一方面,本發明係有關於製造半導體裝置以及其他微型裝置之方法,該等裝置利用之反射折射投影物鏡包括:放置光罩,其提供預刻之圖案於投影物鏡之像面;以具有預定波長之紫外輻射照射光罩;將由具有折射係數遠大於1之浸沒液體所形成之浸沒層設置於投影物鏡之出口比面以及基板之間,基板具有基板表面實質置於投影物鏡之像面;透過浸沒層,將該圖案之影像投影於光敏感之基板上;以及藉由改變光瞳鏡表面形狀以調整該投影物鏡之成像特徵,該光瞳鏡具有位於或接近於該投影物鏡之光瞳面之反射光瞳鏡表面。According to another aspect, the present invention is directed to a method of fabricating a semiconductor device and other microdevices, the reflective refraction projection objective of the device comprising: a reticle providing a pre-engraved pattern on an image surface of the projection objective; Having a predetermined wavelength of ultraviolet radiation illuminating the reticle; immersing the immersion layer formed by the immersion liquid having a refractive index much larger than 1 between the exit surface of the projection objective and the substrate, the substrate having the substrate surface substantially disposed on the image surface of the projection objective; Projecting an image of the pattern onto the light-sensitive substrate through the immersion layer; and adjusting an imaging feature of the projection objective by changing a surface shape of the aperture mirror, the aperture mirror having a light aperture at or near the projection objective The surface of the mirror is reflected.
調整步驟係完成於該基板之至少一曝光之中,以及於該等基板之交換中,以及於介於不同之光罩之交換中,且位於使用該投影物鏡之位置,或在置換不同照明設定之中。The adjusting step is performed in at least one exposure of the substrate, and in the exchange of the substrates, and in the exchange of different masks, and is located at a position where the projection objective is used, or in replacing different illumination settings Among them.
可觀察到透鏡加熱效應可特別地被判斷,若具有很小的連貫性照明設定被使用,例如雙極或四極性照明。在這些條件下,透明光學元件,如被設置位於或接近於光瞳表面,可能遭受空間之非均質輻射負載,導致局部輻射強度最大化,以及於成像之最大衍射之區域中的局部加熱。此可導致透鏡元件之特徵形變以及折射係數之變異,例如,依照雙極或四極性照明而具有二重或四重徑向對稱。這些形變以及折射係數之變異可能依序造成相對應之波前形變而使成像效能惡化。It can be observed that the lens heating effect can be specifically judged if a small coherent illumination setting is used, such as bipolar or quadrupole illumination. Under these conditions, a transparent optical element, such as being placed at or near the pupil surface, may suffer from a heterogeneous radiation loading of the space, resulting in maximizing localized radiation intensity, as well as localized heating in the region of maximum diffraction of imaging. This can result in characteristic deformation of the lens elements as well as variations in refractive index, for example, double or quadruple radial symmetry in accordance with bipolar or quadrupole illumination. These deformations and variations in the refractive index may sequentially cause corresponding wavefront deformations to deteriorate imaging performance.
以上問題之解決方式係為一種製造半導體裝置或其他種類之微型裝置之方法,該等裝置利用之反射折射投影物鏡包括:將具有預定圖案之光罩置於該投影物鏡之該物面;以具有預定波長之紫外線輻射來照射該光罩,其利用照明系統所提供之照明設定;於該照明系統之光瞳面以及於至少光學地共軛光瞳面,調整該照明以提供離軸照明設定,使該光軸之外的區域之光強度大於接近於該光軸之光強度;調整該投影物鏡之該等成像特徵,藉由調適於該離軸照明設定之方式來改變該光瞳鏡表面形狀,如此由空間非均質輻射負載所造成之該等波前像差至少部分可被補償,該等波前像差係由位於或接近於該投影物鏡之一光瞳面的該等光學元件所造成。The solution to the above problem is a method for manufacturing a semiconductor device or other kinds of micro devices, and the reflective refraction projection objective lens used by the devices includes: placing a photomask having a predetermined pattern on the object surface of the projection objective; Ultraviolet radiation of a predetermined wavelength illuminates the reticle, which utilizes illumination settings provided by the illumination system; adjusts the illumination to provide off-axis illumination settings at the pupil plane of the illumination system and at least optically conjugated pupil planes, Having the intensity of the region outside the optical axis greater than the intensity of the light near the optical axis; adjusting the imaging features of the projection objective to change the surface shape of the aperture mirror by adjusting the off-axis illumination setting Thus, the wavefront aberrations caused by the spatially heterogeneous radiation load are at least partially compensated by the optical components located at or near one of the pupil faces of the projection objective .
一般而言,照明設定可依照光罩或其他圖案裝置所提供之圖案而被設定。藉由將具有某一架構之第一光罩更換成具有另一架構之第二光罩,可達成照明設定之更改。有複數次曝光之曝光方法中,兩個或更多的不同照明設定,選擇性地包括離軸照明設定,可被用來照明於連續的曝光步驟中之某一架構。離軸照明設定可以是極性照明設定,例如雙極或四極性照明。In general, the illumination settings can be set according to the pattern provided by the reticle or other patterning device. A change in illumination settings can be achieved by replacing a first reticle having a certain architecture with a second reticle having another architecture. In exposure methods with multiple exposures, two or more different illumination settings, optionally including off-axis illumination settings, can be used to illuminate one of the successive exposure steps. Off-axis illumination settings can be polar illumination settings, such as bipolar or quad-polar illumination.
某些因浸沒層之特徵改變及投影物鏡之特徵改變所造成之誤差,在相對短的時間中可為動態影響,其可被提供此成像誤差(或者其他可影響成像誤差之特性),其係關聯於隨時間而產生之變數之該等光學特性,其包括該浸沒層隨時間改變之該等光學特性,以及因利用極性照明設定、離軸照明設定所導致的改變;此成像誤差藉由適當的偵測器而被偵測,此偵測器產生之感測訊號指示該等隨時間產生之該等改變,而由光瞳鏡操作器所造成之光瞳鏡表面形狀之變化被驅動,以回應該等感測訊號,如此光瞳鏡表面形狀之形變可有效補償至少部份之隨時間產生之改變。光瞳鏡操作器係因此被整合於控制迴圈中以達成即時的成像誤差控制。詳細言之,光瞳鏡操作器可被驅動,如此由浸沒液體之折射係數的改變而造成之場不變誤差貢獻至少部分被補償。更穩定的浸沒微影之製程可被獲得。Some of the errors caused by changes in the characteristics of the immersion layer and changes in the characteristics of the projection objective may be dynamic in a relatively short period of time, which may be provided with this imaging error (or other characteristic that may affect imaging errors). Such optical characteristics associated with variables occurring over time, including such optical characteristics of the immersion layer as a function of time, and changes resulting from the use of polar illumination settings, off-axis illumination settings; The detector is detected, and the sensing signal generated by the detector indicates the changes caused by the time, and the change of the shape of the surface of the aperture mirror caused by the aperture mirror operator is driven to The response signal should be echoed, such that the deformation of the surface shape of the aperture mirror can effectively compensate for at least some of the changes over time. The frog mirror operator is thus integrated into the control loop for immediate imaging error control. In particular, the pupil mirror operator can be driven such that the field invariant error contribution caused by the change in the refractive index of the immersion liquid is at least partially compensated. A more stable process of immersion lithography can be obtained.
舉例而言,使用干涉計或其他合適之直接量測系統,可使成像誤差被直接偵測。也可能利用間接的方法。舉例來說,假若某一浸沒液體被使用,溫度感測器被供來監視形成浸沒層之浸沒液體的溫度,以及,因溫度變化而造成之折射係數的變異,可基於查詢表的測量,依照經驗而被取得,以及動態地由操作光瞳鏡而被補償。For example, using an interferometer or other suitable direct measurement system, imaging errors can be detected directly. It is also possible to use an indirect method. For example, if a immersion liquid is used, the temperature sensor is supplied to monitor the temperature of the immersion liquid forming the immersion layer, and the variation of the refractive index due to the temperature change can be based on the measurement of the look-up table. It is acquired by experience and dynamically compensated by operating the aperture mirror.
選擇性地,或額外地,可利用饋送控制操作用來獲得所欲求之光瞳鏡形狀。舉例,控制單元可接收訊號,此訊號指示照明系統所使用之極性照明的種類,以及控制單元基於查找表格,可提供適當的控制訊號至光瞳鏡操作器,以將光瞳鏡表面形變,如此因局部非均質吸收所導致之透鏡加熱而造成的波前形變可至少部分被補償,而此等透鏡係位於或接近於投影物鏡的光瞳表面。Alternatively, or additionally, a feed control operation can be utilized to obtain the desired pupil mirror shape. For example, the control unit can receive a signal indicating the type of polar illumination used by the illumination system, and the control unit can provide an appropriate control signal to the pupil mirror operator based on the lookup table to deform the surface of the pupil mirror. The wavefront deformation caused by the heating of the lens due to local heterogeneous absorption can be at least partially compensated, and such lenses are located at or near the pupil surface of the projection objective.
先前所述及其他特徵不僅可見於申請專利範圍,也可見於說明書以及圖式,其中各個獨立之特徵可被單獨使用或以組合之方式作為本發明之實施例或用於其他領域,以及,其可單獨地代表可專利性以及具有優點的實施例。The foregoing and other features are not only apparent in the scope of the claims but also in the description and the drawings, wherein the individual features can be used individually or in combination as an embodiment of the invention or in other fields, and The patentable and advantageous embodiments may be represented separately.
以下對於較佳實施例之描述中,有關之物件係為具有積體電路之一層圖案的光罩,或者是其他圖案,例如光柵圖案。物件的影像係投影於晶圓上,此晶圓係用來做為塗佈一層光阻之基板,雖然其他種類的基板也適用,例如液晶顯示器之元件或光柵。In the following description of the preferred embodiment, the object in question is a reticle having a layer pattern of integrated circuits, or other pattern, such as a grating pattern. The image of the object is projected onto the wafer, which is used as a substrate for coating a layer of photoresist, although other types of substrates are also suitable, such as components or gratings of liquid crystal displays.
以下描述具有複數個面鏡之實施例。除非特別描述,否則將依照輻射反射於面鏡上之順序來標號該等面鏡。換句話說,面鏡之標號代表面鏡於輻射之光學路徑上的位置,而非幾何位置。The following describes an embodiment having a plurality of mirrors. Unless otherwise stated, the mirrors will be labeled in the order in which they are reflected on the mirror. In other words, the number of the mirror represents the position of the mirror on the optical path of the radiation, not the geometric position.
於不同實施例中,適當、相同或相似之特徵或特徵組係代表相似之參考定義。In different embodiments, appropriate, identical or similar features or feature sets represent similar reference definitions.
表格供作揭露說明書之圖式所示之設計,而表格係被標以與相對圖式相同的標號。The tables are provided for the design shown in the drawings, and the tables are labeled with the same reference numerals as the drawings.
以下所述之一些實施例中,所有曲鏡之表面曲率有一共同之對稱旋轉軸,係表示為鏡面組軸向。鏡面組軸向重疊於投影物鏡之光軸OA。軸向對稱之光學系統,也被稱作共軸系統或線性系統,係以此方式提供。物面以及像面係平行的。偶數的反射將會發生。而有效運用之物場及像場係離軸的,例如,完全置於光軸之外的位置。所有的系統有以光軸為中心而環繞之環形瞳,因此可被用做光微影技術之投影物鏡。In some of the embodiments described below, the surface curvature of all of the curved mirrors has a common axis of symmetry, expressed as the mirror set axis. The mirror group is axially overlapped with the optical axis OA of the projection objective. An axially symmetric optical system, also referred to as a coaxial system or a linear system, is provided in this manner. The object surface and the image plane are parallel. Even reflections will occur. The effective use of the object field and the image field is off-axis, for example, completely outside the optical axis. All systems have a circular ring that surrounds the optical axis and can therefore be used as a projection objective for photolithography.
在其他實施例中,光軸係被折疊成相互傾斜某一角度之多個軸段。In other embodiments, the optical axis is folded into a plurality of shaft segments that are inclined at an angle to each other.
圖1顯示第一實施例之反射折射投影物鏡100的透鏡區,反射折射投影物鏡100被設計來投影置於平坦物表面OS(物面)的光罩上之圖案之影像於較小的規模之平坦像表面IS(像面),例如4:1之比值,當創造出之兩個真實的中間影像IMI1以及IMI2。置於光軸OA之外的離軸有效物場OF因此被投影於離軸像場IF。圖2圖示如圖1之類型的投影物鏡之變形的簡化代表圖。1 shows a lens area of a catadioptric projection objective lens 100 of a first embodiment, the catadioptric projection objective lens 100 being designed to project an image of a pattern placed on a mask of a flat object surface OS (object surface) on a smaller scale. The flat image surface IS (image surface), for example a ratio of 4:1, creates two real intermediate images IMI1 and IMI2. The off-axis effective object field OF placed outside the optical axis OA is thus projected onto the off-axis image field IF. Figure 2 illustrates a simplified representation of a deformation of a projection objective of the type of Figure 1.
在圖1及圖2中,離軸物場OF中外場點之主要光束CR之路徑係以粗線表示,以便於跟隨投影光束之光束路徑。本申請案之目的,名詞「主要光束」代表自有效運用之物場OF之最外之場點(最遠離光軸)行進至入射光瞳中央的光束。由於旋轉對稱的系統,主要光束可能被選自子午平面之等效場點,如以示範為目的之圖形所示。實質上在物場端為遠心(telecentric)之投影物鏡,散發自物面之主要光束係平行於光學軸,或與光學軸夾一非常小的角度。成像過程進一步之特徵在於軌道光或邊光(trajectory or marginal rays)。「邊光」(marginal rays)在此處被當作自軸像物場點(於光軸上之場點)行進至孔徑光闌(aperture stop)的邊緣的光束。當離軸之有效物場被使用時所造成之漸暈,使得此邊光可能無法構成影像。成像過程之進一步特徵在於「邊緣光線」(rim rays)的軌道。「邊緣光線」在此處被當作自離軸物場場點(離光軸有一距離之場點)行進至孔徑光闌(aperture stop)的邊緣的光束。名詞「上緣光線」係指光線之行進方向使光線與光軸之距離逐漸增加之邊緣光線,也就是說,光線遠離靠近物面的光軸。相反地,名詞「下緣光線」係指光線之行進方向使光線與光軸之距離逐漸縮短之邊緣光線,也就是說,光線朝靠近物面的光軸行進。主要光束以及邊光以及邊緣光束都被選擇做為投影物鏡之光學特徵(也請參考圖4之說明)。這些被選擇之光束與光軸於某一軸點之間的夾角被代表為「主要光束角度」、「邊光角度」等。這些被選擇之光束與光軸於某一軸點之間的半徑距離被代表為「主要光束高度」、「邊光高度」等。In Figs. 1 and 2, the path of the main beam CR of the outer field point in the off-axis object field is indicated by a thick line to facilitate the follow-up of the beam path of the projected beam. For the purposes of this application, the term "primary beam" means the beam that travels from the outermost field point of the object field OF that is effectively used (farth from the optical axis) to the center of the entrance pupil. Due to the rotationally symmetric system, the primary beam may be selected from the equivalent field point of the meridional plane, as shown by the graphical representation for the purposes of the demonstration. Substantially at the end of the object field is a telecentric projection objective, the main beam emitted from the object plane is parallel to the optical axis, or a very small angle to the optical axis. The imaging process is further characterized by trajectory or marginal rays. Here, "marginal rays" are used as a beam of light traveling from the axis of the object object point (the field point on the optical axis) to the edge of the aperture stop. The vignetting caused by the effective off-axis object field is used, so that the side light may not constitute an image. The imaging process is further characterized by the orbit of "rim rays". The "edge ray" is here taken as a beam that travels from the off-axis object field point (the point of the field at a distance from the optical axis) to the edge of the aperture stop. The term "upper edge ray" refers to the edge ray whose direction of travel is such that the distance between the ray and the optical axis is gradually increased, that is, the light is away from the optical axis near the object plane. Conversely, the term "lower edge ray" refers to the edge ray that causes the direction of travel of the ray to gradually shorten the distance between the ray and the optical axis, that is, the ray travels toward the optical axis near the object plane. The primary and side and edge beams are selected as the optical features of the projection objective (see also Figure 4 for an illustration). The angle between the selected beam and the optical axis at a certain axis point is represented as "main beam angle", "edge light angle", and the like. The radius distance between the selected beam and the optical axis at a certain axis point is represented as "main beam height", "edge light height", and the like.
投影物鏡100可以是被分為五個群組之光學元件,沿著平直(未折疊)的光學共軸OA排列,也就是說,第一透鏡組LG1緊鄰著物面且具有正向折射強度,而鏡組MG緊鄰著第一透鏡組LG1,且具有整體正向強度;具有正向折射強度之第二透鏡組LG2緊鄰著鏡組MG,第三透鏡組LG3緊鄰著第二透鏡組LG2,且具有負向折射強度;以及,緊接著第三透鏡組LG3之第四透鏡組LG4具有正向折射強度。透鏡組LG1至LG4皆為純折射,而鏡組MG係純反射(僅有反射面)。The projection objective 100 may be an optical element divided into five groups, arranged along a straight (unfolded) optical coaxial OA, that is, the first lens group LG1 is adjacent to the object surface and has a positive refractive power. The mirror group MG is adjacent to the first lens group LG1 and has an overall positive intensity; the second lens group LG2 having a positive refractive power is adjacent to the mirror group MG, and the third lens group LG3 is adjacent to the second lens group LG2. And having a negative refractive power; and, the fourth lens group LG4 of the third lens group LG3 has a forward refractive power. The lens groups LG1 to LG4 are purely refracting, and the mirror group MG is purely reflective (only reflective surfaces).
第一透鏡組LG1(也為前端透鏡組)被設計用來將投影物鏡之遠心入射光瞳以強大的正向強度成像於第一光瞳面P1,因此第一透鏡組LG1以類似於傅立葉(Fourier)透鏡組之動作完成單一傅立葉轉換。此傅立葉轉換導致相對大的主要光束角度CRAp1 ,其係與第一光瞳面P1有28度之夾角。因此,於第一光瞳面之光瞳直徑係相對小。The first lens group LG1 (also the front lens group) is designed to image the telecentric incident pupil of the projection objective with a strong positive intensity on the first pupil plane P1, so that the first lens group LG1 is similar to Fourier ( The action of the Fourier lens group completes a single Fourier transform. This Fourier transform results in a relatively large main beam angle CRA p1 which is at an angle of 28 degrees to the first pupil plane P1. Therefore, the pupil diameter on the first pupil plane is relatively small.
自第一光瞳面P1所產生之輻射係入射於第一鏡片M1,第一鏡片M1為非球狀,面對物端為凹鏡面;且輻射光學順向地形成第一中間影像IMI1且與第一鏡片M1間有一距離。之後,輻射係反射於被設計為非球狀凹鏡之第二鏡片M2,且以斜角反射至具有包含光軸OA之反射面之第三鏡片M3。第三鏡片之凹鏡面位於第二光瞳面P2,於第二光瞳面P2主要光束與光軸交會,因此形成光瞳鏡PM。由於非常大的主要光束角度CRApm ~42度在第二光瞳面形成,得到一小型的第二光瞳(Lagrange invariant:拉格朗不變量)。具有大主要光束角度且反射自第三鏡片M3(光瞳鏡PM)之輻射可被測得,當其反射於第四鏡片M4之非球面之像端之凹鏡表面,第四鏡片M4具有之光學強度被設計來聚合輻射光束並立即下行朝第二中間影像IMI2行進,並與第四鏡片M4間有一距離。The radiation generated from the first pupil plane P1 is incident on the first lens M1, the first lens M1 is non-spherical, and the object end is a concave mirror surface; and the radiation optics sequentially forms the first intermediate image IMI1 and There is a distance between the first lenses M1. Thereafter, the radiation is reflected by the second lens M2 designed as a non-spherical concave mirror, and is reflected at an oblique angle to the third lens M3 having the reflecting surface including the optical axis OA. The concave mirror surface of the third lens is located on the second pupil plane P2, and the main beam intersects the optical axis on the second pupil plane P2, thereby forming the pupil mirror PM. Since a very large main beam angle CRA pm ~42 degrees is formed on the second pupil plane, a small second aperture (Lagrange invariant) is obtained. The radiation having a large main beam angle and reflected from the third lens M3 (the pupil mirror PM) can be measured, and when it is reflected on the concave mirror surface of the aspherical image end of the fourth lens M4, the fourth lens M4 has The optical intensity is designed to polymerize the radiation beam and immediately travel down the second intermediate image IMI2 and a distance from the fourth lens M4.
調整光學設計是有可能的,如此鏡面不會有非球面形狀,而會有一球面形狀。例如,第二鏡片M2以及第四鏡片M4可能以球面鏡來實現。進一步而言,也可能以具有不同表面特徵(表面形狀)之不同面鏡來建構第二鏡片M2及第四鏡片M4,且/或可以具有不同表面特徵(表面形狀)之不同面鏡來建構第一鏡片M1以及第三鏡片M3。此例中,至少一個獨立的面鏡可能以球面鏡來實現,而不是非球面鏡。It is possible to adjust the optical design so that the mirror does not have an aspherical shape but a spherical shape. For example, the second lens M2 and the fourth lens M4 may be implemented with a spherical mirror. Further, it is also possible to construct the second lens M2 and the fourth lens M4 with different mirrors having different surface features (surface shapes), and/or different mirrors having different surface features (surface shapes) to construct the first A lens M1 and a third lens M3. In this case, at least one of the separate mirrors may be implemented as a spherical mirror rather than an aspherical mirror.
很明顯地,位於物面OS(也稱為物高)之主要光束高度遠小於位於第二鏡片M2之主要光束高度,其立即向上行進至光瞳鏡M3;且,其也遠小於在第四鏡片M4之主要光束高度,其立即向下行進至光瞳鏡。在一較佳實施例中,在物面上之主要光束高度CRHO 與面鏡上之主要光束高度CRHM (其立即上行與下行至光瞳面)的比值實質上大於1,例如大於2或大於2.5。圖1之實施例中,面鏡M2以及M4之比值大約為2.7。Obviously, the main beam height at the object surface OS (also referred to as the object height) is much smaller than the main beam height at the second lens M2, which immediately travels up to the pupil mirror M3; and it is also much smaller than in the fourth The main beam height of lens M4, which immediately travels down to the pupil mirror. In a preferred embodiment, the ratio of the main beam height CRH O on the object plane to the main beam height CRH M on the mirror (which immediately goes up and down to the pupil plane) is substantially greater than 1, such as greater than 2 or Greater than 2.5. In the embodiment of Figure 1, the ratio of mirrors M2 and M4 is approximately 2.7.
輻射於接近於第一光瞳P1之鏡組入口MGI進入鏡組,且於接近第二中間影像,也就是接近場面之鏡組出口MGO射出鏡組。與光軸相垂直地排列且置於第一鏡片與第二鏡片的頂點之間的鏡組平面MGP,於光束射出鏡組之鏡組出口前被通過五次。因此,被定義於鏡組入口與鏡組出口間之軸向小空間中,可獲得四次反射。The mirror group entrance MGI radiating close to the first aperture P1 enters the mirror group, and approaches the second intermediate image, that is, the mirror group exit MGO of the near scene. The mirror group plane MGP arranged perpendicular to the optical axis and placed between the apexes of the first lens and the second lens is passed five times before the beam exits the lens group exit of the mirror group. Therefore, four reflections are obtained in the axial small space defined between the entrance of the lens group and the exit of the lens group.
相對於有效物場OF被放大之第二中間影像IMI2以純折射的物鏡部件(也稱為後透鏡組)被成像至像面IS,純折射的物鏡部件包含第二透鏡組LG2,第三透鏡組LG3,以及第四透鏡組LG4。被指示為一局部最小光束直徑之投影光束的壓縮部係形成於第三透鏡組LG3之負透鏡的區域。第二透鏡組LG2具有正向的折射光強度且實質上做為一場鏡組,用於將第四鏡片M4之光瞳出口之成像更接近於反射鏡組。此允許之後的透鏡被設計為具有相對小之光學可調整直徑,於一整體短的軸長上。第三透鏡組LG3具有負向折射強度,因此組成壓縮部或光束直徑之”腰部”。此負透鏡組可增加在第二中間影像IMI2之後的數值孔徑。第三透鏡組LG3與第四透鏡組LG4之後的部分一起形成相反之遠距系統,第四透鏡組LG之後的部分係指界於第三透鏡組LG3以及第三光瞳面P3之間的部分;其遠距系統具有一小的軸向長度,不管要求有最小直徑於第二中間影像IMI之小數值孔徑之系統孔徑。The second intermediate image IMI2, which is enlarged with respect to the effective object field OF, is imaged to the image plane IS by a purely refractive objective lens component (also referred to as a rear lens group), and the purely refractive objective lens component includes a second lens group LG2, a third lens group LG3, and the fourth lens group LG4. The compressed portion of the projected beam, which is indicated as a partial minimum beam diameter, is formed in the region of the negative lens of the third lens group LG3. The second lens group LG2 has a positive refracted light intensity and substantially serves as a field mirror for imaging the pupil exit of the fourth lens M4 closer to the mirror group. This allowed lens is designed to have a relatively small optically adjustable diameter over an overall short axial length. The third lens group LG3 has a negative refractive power and thus constitutes a "waist" of the compression portion or the beam diameter. This negative lens group can increase the numerical aperture after the second intermediate image IMI2. The third lens group LG3 and the portion after the fourth lens group LG4 together form an opposite telecentric system, and the portion after the fourth lens group LG is bounded between the third lens group LG3 and the third pupil plane P3. The remote system has a small axial length, regardless of the system aperture required to have a minimum diameter to the small numerical aperture of the second intermediate image IMI.
於另一描述中,投影物鏡100之光學元件組成第一成像物鏡部件,其包含第一透鏡組LG1之透鏡以及第一鏡片M1,用於將光罩之物場區域之圖案成像於第一中間影像IMI1;組成第二成像物鏡部件,其包含光瞳鏡PM,用於將第一中間影像成像於第二中間影像IMI2;組成第三成像物鏡部件,用於將第二中間影像成像於像面IS。第一物鏡部件係為反射折射的(於第一透鏡組LG中具有六個透鏡以及一個凹鏡M1),第二物鏡部件係為純反射(catoptric)且由凹鏡M2、M3以及M4所組成;以及,由LG2、LG3以及LG4所組成之第三物鏡部件係為純折射。放大率為(β=2.1)之反射折射第一物鏡部件定義第一中間影像IMI1之大小,以及,與第二鏡片M2之相互作用可定義於光瞳鏡之投影光束的校正狀態。立即向上行進至光瞳鏡之面鏡M2之主要光束高度的絕對值,以及立即向下行進至光瞳鏡之面鏡M4之主要光束高度的絕對值,係遠大於在物面上的主要光束高度,而此種條件式係對於有小型光瞳之光瞳鏡較佳。於光瞳鏡上造成小型光瞳之大主要光束角度,可由第四鏡片M4所測得,以形成一光束用來向第二中間影像以及向像端之折射透鏡組LG2、LG3以及LG4聚合。此部分(後透鏡組)係較佳地用於控制成像像差以及提供大的像側數值孔徑NA=0.93。In another description, the optical element of the projection objective 100 constitutes a first imaging objective component comprising a lens of the first lens group LG1 and a first lens M1 for imaging the pattern of the object field region of the reticle in the first middle The image IMI1; constitutes a second imaging objective component, comprising a pupil mirror PM for imaging the first intermediate image to the second intermediate image IMI2; and forming a third imaging objective component for imaging the second intermediate image to the image plane IS. The first objective lens component is catadioptric (having six lenses in the first lens group LG and one concave mirror M1), the second objective lens component is purely reflective (catoptric) and composed of concave mirrors M2, M3 and M4 And, the third objective lens component consisting of LG2, LG3, and LG4 is pure refraction. The refraction of the first objective lens component (β = 2.1) defines the size of the first intermediate image IMI1, and the interaction with the second lens M2 can be defined as the correction state of the projection beam of the pupil mirror. The absolute value of the main beam height of the mirror M2 that immediately travels up to the pupil mirror, and the absolute value of the main beam height of the mirror M4 that immediately travels down to the pupil mirror, is much larger than the main beam on the object plane Height, and this conditional type is preferred for a light-shield mirror with a small aperture. The large beam angle of the small aperture on the pupil mirror can be measured by the fourth lens M4 to form a beam for polymerization to the second intermediate image and the refractive lens groups LG2, LG3 and LG4 toward the image end. This portion (rear lens group) is preferably used to control imaging aberrations and to provide a large image side numerical aperture NA = 0.93.
純反射(catoptric)鏡組MG係可提供帕茲伐總合的過度校正,以抵消透鏡之正向折射強度之反作用。為此起見,鏡組MG包含第一凹鏡M1置於相反於物場OF之光軸的一側,第二凹鏡M2置於光軸相同之一側,而第三凹鏡M3置於光軸上做為光瞳鏡PM,以及第四凹鏡M4置於物場的一側。鏡組入口MGE係形成於凹鏡M2以及M4互相面對的邊緣之間,位於鏡組之物場端,幾何位置上接近第一光瞳面P1。鏡組入口MGE可能以有共同基板的凹鏡M2及M4上之孔洞或在其上鑽孔而形成。鏡組出口MGO則位於光軸OA之外,鄰近光瞳鏡M3的邊緣,於第一凹鏡M1之相反側。如以下對圖3更詳細的說明,光瞳鏡M3以及第一凹鏡M1可能於相同基板上形成,以形成一對面鏡,雖然,也可能使用分別的基板(請見圖2)。The purely reflective (catoptric) mirror MG system provides over-correction of the Pazval sum to counteract the reaction of the forward refractive power of the lens. For this purpose, the mirror group MG includes a first concave mirror M1 placed on the side opposite to the optical axis of the object field OF, a second concave mirror M2 placed on the same side of the optical axis, and the third concave mirror M3 placed The optical axis is used as the pupil mirror PM, and the fourth concave mirror M4 is placed on one side of the object field. The mirror group inlet MGE is formed between the mutually facing edges of the concave mirrors M2 and M4, and is located at the object field end of the mirror group, and is geometrically close to the first pupil plane P1. The mirror set inlet MGE may be formed by drilling holes in the concave mirrors M2 and M4 having a common substrate or drilling holes thereon. The mirror group exit MGO is located outside the optical axis OA, adjacent to the edge of the pupil mirror M3, on the opposite side of the first concave mirror M1. As explained in more detail below with respect to Figure 3, the pupil mirror M3 and the first concave mirror M1 may be formed on the same substrate to form a pair of mirrors, although separate substrates may be used (see Figure 2).
投影物鏡100係被設計為乾式物鏡,用於操作於波長λ=193nm且在像端具有數值孔徑=0.93。矩形有效物場OF之大小係為26nm*5.5mm。像場的半徑(直徑的一半)y’=18mm。規格摘要於表格1。最左邊一行表列了折射、反射或其它被標示之表面;第二行表列了所在之表面的半徑r(以mm表示),第三行表列距離d,係為介於該表面以及下個表面之距離,此參數被標示為光學元件之「厚度」;第四行表列被用做製造該光學元件之材料,第五行標明該材質之折射係數。第六行列出光學元件光學可利用且清楚之半徑(以mm表示)。於表格中半徑r=0代表一平面(有無窮大之半徑)。The projection objective 100 is designed as a dry objective for operation at a wavelength λ = 193 nm and a numerical aperture = 0.93 at the image end. The size of the rectangular effective object field OF is 26 nm * 5.5 mm. The radius of the image field (half the diameter) y' = 18 mm. The specifications are summarized in Table 1. The leftmost row lists the refraction, reflection, or other marked surface; the second row lists the radius r (in mm) of the surface on which it is located, and the third row lists the distance d between the surface and the bottom. For the distance of the surface, this parameter is indicated as the "thickness" of the optical component; the fourth row is used as the material for the optical component, and the fifth row indicates the refractive index of the material. The sixth row lists the optically usable and clear radius (expressed in mm) of the optical component. In the table, the radius r=0 represents a plane (with a radius of infinity).
表格1中之一些表面係為非球狀表面。表格1A表列這些非球狀表面之相對應資料,弦弧間最大距離(sagitta)或將這些表面之形狀的上升高度p(h)當作高度h之函數,可以下列的等式計算:p(h)=[((1/r)h2 )/(1+SQRT(1-(1+K)(1/r)2 h2 ))]+C1*h4 +C2*h6 +....,其中半徑之倒數1/r係為於表面頂點之表面曲率,而高度h為該表面上之一點與光軸之距離。弦弧間最大距離(sagitta)或上升高度p(h)因此代表著自表面頂點至該點的距離,其係沿著Z軸方向測量,也就是沿著光軸。常數K、C1、C2等皆列於表格1A之中。Some of the surfaces in Table 1 are non-spherical surfaces. Table 1A lists the corresponding data for these non-spherical surfaces. The maximum distance between the arcs (sagitta) or the rise height p(h) of the shape of these surfaces is taken as a function of height h, which can be calculated by the following equation: p (h)=[((1/r)h 2 )/(1+SQRT(1-(1+K)(1/r) 2 h 2 ))]+C1*h 4 +C2*h 6 +...., where radius The reciprocal 1/r is the surface curvature at the surface apex, and the height h is the distance between one of the points on the surface and the optical axis. The maximum distance (sagitta) or rise height p(h) between the arcs of the string thus represents the distance from the surface apex to that point, which is measured along the Z-axis, that is, along the optical axis. The constants K, C1, C2, etc. are listed in Table 1A.
圖1中之投影物鏡100係為反射折射線內系統,以至少兩相衝突之要求條件來看為最佳化。首先,線內建構(沒有折疊鏡、穩固黏著技術等)的好處可從大的像側數值孔徑獲得,同時間仍保持小型物場之設計。承上所述,漸暈控制係為關鍵。其次,藉由光瞳鏡表面之表面形狀形變,光瞳鏡被提供來促成成像特性的動態或靜態控制。由於光瞳鏡係置於光軸上,光瞳鏡可形成投影光束之障礙物,使得漸暈控制更加困難。第三,對光瞳鏡之投影光束校正狀態小心控制被發現是必要的,若於整個場中將被影響為實質常數之目標成像像差控制被要求。此處由投影物鏡100之範例所示之解決方式注意到以上這些需求(也請見圖3及圖4)。The projection objective 100 of Figure 1 is a catadioptric in-line system that is optimized for the requirements of at least two phase conflicts. First, the benefits of in-line construction (no folding mirrors, solid adhesion techniques, etc.) can be obtained from a large image side numerical aperture while still maintaining a small object field design. As stated above, the vignetting control system is the key. Second, by deforming the surface shape of the pupil mirror surface, a pupil mirror is provided to facilitate dynamic or static control of the imaging characteristics. Since the pupil mirror is placed on the optical axis, the pupil mirror can form an obstacle to the projected beam, making vignetting control more difficult. Third, careful control of the state of the projection beam correction of the pupil mirror is found to be necessary if the target imaging aberration control that would be affected as a substantial constant throughout the field is required. The above requirements are noted here by the solution shown by the example of projection objective 100 (see also Figures 3 and 4).
由於投影光束應被導引穿過無漸暈之線內設計的面鏡,須將與漸暈有關之關鍵性區域的大小保持愈小愈好。例子中,其對應於一些要求,以使投影光束之光瞳鏡,也就是投影光束於光瞳表面交會之處,於鏡組的區域中保持為愈小愈好。根據拉格朗不變量(Lagrange invariant),此要求轉換為提供特別大之主要光束入射角於瞳所在之位置,處於或靠近鏡組。將主要光束CR明顯彎向光軸之第一鏡組LG1(傅立葉鏡組或前置鏡組)之大正向強度提供第一光瞳面P1小尺寸的瞳,其因此允許小的鏡組入口MG1以及將極靠近光軸之面鏡M2以及M4之反射區域延伸。結合凹透鏡M1以及M2之正向強度,於光瞳鏡PM之主要光束角度係進一步被增加至CRAPM ≒42°,導致於光瞳鏡PM所在之第二光瞳面P2有小的光束直徑。當光瞳鏡PM(=M3)之反射區域RA3可保持小尺寸,於第四鏡片M4以及像面之間的漸暈控制可簡化,且其可能將被利用的第一鏡片M1之反射區域RA1以及光瞳鏡M3之反射區域RA3分開。換言之,投影光束對面鏡M1以及M3之反射的路徑並未重疊。這是利用光瞳鏡PM做為可動態調整之操作器的必要條件之一,以對投影物鏡之成像特性產生動態影響。Since the projected beam should be directed through the mirror designed in the line without vignetting, the size of the critical area associated with vignetting should be kept as small as possible. In the example, it corresponds to some requirements such that the pupil of the projected beam, that is, where the projected beam meets at the pupil surface, is kept as small as possible in the area of the mirror. According to the Lagrange invariant, this requirement is converted to provide a particularly large primary beam incident angle at the location of the 瞳, at or near the mirror. The large forward intensity of the first mirror group LG1 (Fourier mirror group or front lens group) that significantly bends the main beam CR toward the optical axis provides a small size of the first pupil plane P1, which thus allows a small mirror group entrance MG1 And extending the reflection regions of the mirrors M2 and M4 that are very close to the optical axis. In combination with the positive intensities of the concave lenses M1 and M2, the main beam angle at the pupil mirror PM is further increased to CRA PM ≒ 42°, resulting in a small beam diameter at the second pupil plane P2 where the pupil PM is located. When the reflection area RA3 of the pupil mirror PM (= M3) can be kept small, the vignetting control between the fourth lens M4 and the image plane can be simplified, and the reflection area RA1 of the first lens M1 which may be utilized is possible. And the reflection area RA3 of the pupil mirror M3 is separated. In other words, the paths of the projection beams to the reflections of the mirrors M1 and M3 do not overlap. This is one of the necessary conditions for using the aperture mirror PM as a dynamically adjustable operator to dynamically influence the imaging characteristics of the projection objective.
進一步而言,重點係在於光瞳鏡PM,也就是第二光瞳面P2,之投影光束之校正狀態。一最佳化之條件係有關於促使對成像像差之場不變校正可被獲得,若對應於物場中不同場點之次孔徑有相同之尺寸與形狀,且於光瞳表面中相互完全重疊。假設此條件被滿足,光瞳鏡之反射特性之局部變化,例如將鏡表面產生形變,將會對來自不同場點之所有光束產生相似效果,如此於像面中產生場不變效應。另一方面來說,假若不同場點之次孔徑並未於光瞳面重疊,則光瞳鏡之反射特性之局部變化將會對來自不同場點之光束產生不同影響,如此於場中產生校正效果之變化。Further, the focus is on the correction state of the projection beam of the pupil mirror PM, that is, the second pupil plane P2. An optimization condition is related to causing a field-invariant correction for imaging aberrations to be obtained if the secondary apertures corresponding to different field points in the object field have the same size and shape and are completely complementary to each other in the pupil surface. overlapping. Assuming that this condition is met, local variations in the reflection characteristics of the pupil mirror, such as deformation of the mirror surface, will produce similar effects for all beams from different field points, thus producing a field-invariant effect in the image plane. On the other hand, if the secondary apertures of different field points do not overlap on the pupil plane, the local variation of the reflection characteristics of the pupil mirror will have different effects on the beams from different field points, thus producing corrections in the field. The effect changes.
圖4中這些條件被以下光線所代表;來自於光軸OA上之場點FPO之邊緣光線MR,以及代表來自離軸場點FP1之部分光束,也就是主要光束CR,上緣光束RRU以及下緣光束RRL。以上所述之理想例子中(位於光瞳面所有場點中之光束有完全重疊之次孔徑),主要光束CR應與光軸交錯於光瞳鏡PM之折射面的位置。與理想狀況之偏差將以主要光束之光束高度(與光軸之半徑距離)之參數CRHi 被描述,主要光束係於光瞳鏡PM之最外場點FP1進入光學系統。與代表兩倍邊緣光束MR之高度D0 相較之下,橫向位移較小。進一步而言,物鏡於場點FP1(以參數Di 表示)之光瞳鏡PM,其瞳入口的像之子午線直徑理想上應對應於直徑D0 ,或者,換言之,Di 與D0 之比值Di /D0 應等於或接近於1。以下數值可由圖1所示之實施例所獲得:| CRHi |/D0 =0.03,以及Di /D0 =0.991。實質上,同樣的條件可應用於弦弧間最大距離區段(sagittal section)。一般而言,條件| CRHi |/D0 <0.1以及0.9≦Di /D0 ≦1.1應被遵守,若光瞳鏡表面的形狀之操作器必須於像場上所有場點的校正狀態有實質上一常數效果。These conditions in Fig. 4 are represented by the following rays; the edge ray MR from the field point FPO on the optical axis OA, and the partial beam representing the off-axis field point FP1, that is, the main beam CR, the upper edge beam RRU and the lower Edge beam RRL. In the above-mentioned ideal example (the light beams in all the field points of the pupil plane have completely overlapping sub-apertures), the main beam CR should be interlaced with the optical axis at the position of the refractive surface of the pupil mirror PM. The deviation from the ideal condition will be described by the parameter CRH i of the beam height of the main beam (distance from the radius of the optical axis), and the main beam is incident on the optical system at the outermost field point FP1 of the pupil mirror PM. The lateral displacement is small compared to the height D 0 representing the double edge beam MR. Further, the pupil mirror PM of the objective lens at the field point FP1 (indicated by the parameter D i ), the meridian diameter of the image of the pupil entrance should ideally correspond to the diameter D 0 or, in other words, the ratio of D i to D 0 . D i /D 0 should be equal to or close to 1. The following values can be obtained from the embodiment shown in Figure 1: |CRH i |/D 0 =0.03, and D i /D 0 =0.991. In essence, the same conditions can be applied to the sagittal section between strings. In general, the condition | CRH i | / D 0 <0.1 and 0.9 ≦ D i / D 0 ≦ 1.1 should be observed, if the shape of the mirror surface of the operator must be corrected in all field points on the image field Essentially a constant effect.
圖3顯示圖1中之鏡組放大後之細節,以強調於光瞳鏡PM周圍效能條件之細節。以建構式的觀點來看,此處顯示出第一鏡片M1以及第三鏡片M3構成一對凹透鏡組,於一共通的基板上被構成。基板有厚實且機構上堅硬的部分,以提供一帶著反射層之凹表面以構成第一鏡片M1。與堅硬部分RP一體成形的為一相對薄且有彈性之部分FP,其為了光瞳鏡PM帶有折射的塗佈。面鏡基板上彈性部分FP的背面形成一個凹口。光瞳鏡操作器PMM之複數個觸發器(以箭頭表示)位於凹口內,且耦合於彈性部分FP之背面。觸發器被光瞳鏡控制單元PMCU所控制,其可整合為投影曝光裝置之中央控制單元的一部分。光瞳鏡操作器控制單元連接以接收代表光瞳鏡表面欲形變之訊號。光瞳鏡操作器以及相對應之控制單元實質上可被設計成如美國專利申請案2004/0144915揭露之內容。對應之揭露內容係被併入本申請案作為參考。任何合適之光瞳鏡操作器的架構可能替代使用,例如,使用電機式觸發器,如壓電式元件,反應液壓改變之觸發器,電性/磁性觸發器。這些觸發器可能被用來將連續性(未打破)之光瞳鏡表面形變。光瞳鏡操作器可能也包含一或更多影響面鏡之局部溫度變化之加熱元件或冷卻元件,以致所欲形成之光瞳鏡表面形變。電阻加熱器或珀爾帖(Peltier)元件可被用做供以上目的。光瞳鏡也可以被設計成多面鏡陣列,擁有複數個單微面鏡,其反應對應之驅動信號而之間可相對移動。合適的多面鏡陣列被揭露於例如美國專利申請案2006/0039669。光瞳鏡可能依照一些原理而被設計,如國際公開申請案WO 2003/093903,揭露內容將合併於此處作為參考。Figure 3 shows an enlarged detail of the mirror of Figure 1 to emphasize the details of the performance conditions around the pupil PM. From the viewpoint of construction, it is shown here that the first lens M1 and the third lens M3 constitute a pair of concave lens groups, and are formed on a common substrate. The substrate has a thick and mechanically rigid portion to provide a concave surface with a reflective layer to form the first lens M1. Formed integrally with the hard portion RP is a relatively thin and resilient portion FP which is provided with a refractive coating for the pupil mirror PM. The back surface of the elastic portion FP on the mirror substrate forms a notch. A plurality of flip-flops (indicated by arrows) of the pupil mirror operator PMM are located within the recess and are coupled to the back of the resilient portion FP. The trigger is controlled by the pupil mirror control unit PMCU, which can be integrated as part of the central control unit of the projection exposure device. The light mirror operator control unit is coupled to receive a signal representative of the surface of the pupil mirror to be deformed. The light mirror operator and the corresponding control unit can be substantially designed as disclosed in U.S. Patent Application Serial No. 2004/0144915. Corresponding disclosures are incorporated herein by reference. The architecture of any suitable aperture mirror operator may be used instead, for example, using a motor-type trigger, such as a piezoelectric element, a reaction-hydraulic change trigger, an electrical/magnetic trigger. These triggers may be used to deform the continuity (unbroken) light frog mirror surface. The pupil mirror operator may also contain one or more heating elements or cooling elements that affect the local temperature variation of the mirror such that the surface of the pupil mirror to be formed is deformed. A resistive heater or Peltier element can be used for the above purposes. The aperture mirror can also be designed as a polygon mirror array with a plurality of single micromirrors that are relatively movable between the corresponding drive signals. A suitable array of polygon mirrors is disclosed, for example, in U.S. Patent Application Serial No. 2006/0039669. The aperture mirror may be designed in accordance with some principles, such as the International Publication No. WO 2003/093903, the disclosure of which is incorporated herein by reference.
以光學的角度來看,值得注意的是,被利用之第一鏡片M1之反射區域RA1(以粗體標示)並未與光瞳鏡M3對應之反射區域RA3重疊。此特性可使光瞳鏡表面的形狀改變,且不影響於第一鏡片M1所產生之反射。並且,此設計被最佳化成與投影光束的焦散狀況有關,此投影光束係為位於凹鏡與透鏡之折射區域,尤其是第二透鏡組LG2之第一個透鏡,其在第二中間影像後,立即使光線往下行進至鏡組出口。以上係經由提供中間影像而被完成,此中間影像位於離該等面鏡以及第二透鏡組LG2之第一個透鏡之光學表面相對遠之距離,此中間影像實質上為了像散以及慧差(coma)而被校正。於折射或反射之光學表面上避免焦散狀況有助於避免大的局部輻射密度以及簡化選擇性的像差控制。進一步而言,避免表面上之焦散可使規格之品質更容易達成。From an optical point of view, it is worth noting that the reflective area RA1 (in bold) of the utilized first lens M1 does not overlap the reflective area RA3 corresponding to the pupil mirror M3. This property can change the shape of the surface of the pupil mirror without affecting the reflection generated by the first lens M1. Moreover, the design is optimized to be related to the caustics of the projected beam, which is the refractive area of the concave mirror and the lens, in particular the first lens of the second lens group LG2, which is in the second intermediate image. Immediately, the light travels down to the exit of the mirror. The above is accomplished by providing an intermediate image located at a relatively distant distance from the optical surfaces of the mirrors and the first lens of the second lens group LG2, the intermediate image being substantially for astigmatism and coma ( Corrected by coma). Avoiding caustics on optical surfaces that are refracted or reflected helps to avoid large localized radiation densities and simplifies selective aberration control. Further, avoiding caustics on the surface makes the quality of the specification easier to achieve.
圖1之實施例可被調整以增加於一相對短的時間內操作影像品質的選擇性。例如,投影物鏡可包含至少一額外面鏡,其鏡表面可被連接於此面鏡之相關操作器操作。有鑑於可被操作之光瞳鏡一般而言係被置於邊緣光束高度MRH超過主要光束高度CRH之處,上述之額外面鏡光學上可被置於較靠近場面之處,尤其是在光束高度比值MRH/CRH小於1或甚至小於0.5的位置。光學上位於接近場面之適應性面鏡(具有可被操作器改變表面之面鏡)可被用來校正場從屬像差。如第一實施例之修改,藉由提供類似於建構及操作上述光瞳鏡操作器之場鏡操作器,光學上置於接近於鄰接場面(中間影像IMI1)之第一鏡片M1或鏡組MG可能被設計為適應性面鏡。由於光瞳鏡M3以及場鏡M1兩者皆可能被形成於相同的基板上,為了場鏡操作器以及光瞳鏡操作器而被設計之觸發器,可被相互連接以簡易建構。做為替代者,或額外的,光學上皆接近於場面之第二鏡片M2以及第四鏡片M4至少其一,可被設計為具有可被操作器調整或改變之鏡表面之面鏡。面鏡M2與M4兩者皆被形成於相同的基板上,而共同的觸發器機構可被應用於此例中。The embodiment of Figure 1 can be adjusted to increase the selectivity of operating image quality over a relatively short period of time. For example, the projection objective can include at least one additional mirror whose mirror surface can be operated by an associated operator attached to the mirror. In view of the fact that the operable aperture mirror is generally placed where the edge beam height MRH exceeds the main beam height CRH, the additional mirror described above can be optically placed closer to the scene, especially at the beam height. The ratio MRH/CRH is less than 1 or even less than 0.5. An adaptive mirror that is optically located near the scene (with a mirror that can be changed by the operator) can be used to correct field subordinate aberrations. As a modification of the first embodiment, the first lens M1 or the mirror group MG optically placed close to the adjacent scene (intermediate image IMI1) is provided by providing a field mirror operator similar to the construction and operation of the above-described diaphragm operator. May be designed as an adaptive mirror. Since both the pupil mirror M3 and the field lens M1 may be formed on the same substrate, the flip-flops designed for the field mirror operator and the pupil mirror operator may be connected to each other for easy construction. As an alternative, or in addition, at least one of the second lens M2 and the fourth lens M4, which are optically close to the scene, can be designed as a mirror having a mirror surface that can be adjusted or changed by the operator. Both the mirrors M2 and M4 are formed on the same substrate, and a common trigger mechanism can be applied to this example.
圖5顯示之第二實施例為線內投影物鏡500,投影物鏡500具有相關於圖1與圖2大體上之佈局,有關於光學元件組(透鏡組、鏡組)之類型和順序,以及整個系統中之投影光束的軌跡。相對應之敘述請參考。元件和元件組具有相似之特徵,如先前實施例以相同參考定義所指出者。此設計之規格係列於表格5以及表格5A。The second embodiment shown in FIG. 5 is an in-line projection objective 500 having a general layout relating to FIGS. 1 and 2, relating to the type and order of the optical element groups (lens group, lens group), and the whole. The trajectory of the projected beam in the system. Please refer to the corresponding description. The elements and group of elements have similar features as indicated by the same referenced definition in the previous embodiments. The specifications for this design are in Table 5 and Table 5A.
投影物鏡500被設計為一浸沒物鏡於λ=193nm,具有像側數值孔徑NA=1.2當被結合使用於高係數之浸沒液體I之中,例如純水,介於投影物鏡之出口面以及像面IS之間。此設計係最佳化於矩形有效之像場,此像場不會有成像漸暈且場尺寸為26*5.5 mm2 。The projection objective 500 is designed as an immersion objective lens at λ=193 nm, and has an image side numerical aperture NA=1.2 when used in combination with a high coefficient immersion liquid I, such as pure water, between the exit surface of the projection objective and the image plane. Between IS. This design is optimized for a rectangular effective image field that does not have imaging vignetting and a field size of 26*5.5 mm 2 .
如圖1所示之實施例,包含鏡組MG之第一鏡片M1之反射折射第一物鏡部件可造出第一中間影像IMI1,位於鏡組中鏡與鏡之間的空間。鏡組MG之第二、第三以及第四鏡片M1至M4構成第二,反射成像之次系統,以自第一中間影像構成第二中間影像IMI2。透鏡組LG2,LG3以及LG4構成第三,折射之物鏡部件,以對第二中間影像IMI2以較低之放大率(有關放大率之比值β=-0.125)再次成像於像面IS。顯而易見的是,介於壓縮部CON與像面IS之間之像端腰部中之最大透鏡直徑,相對於圖1中較低數值孔徑之系統是提高的,其中,像端腰部係接近位於靠近第三光瞳面P3之孔徑光闌AS。不變的是,光瞳鏡PM(第三鏡片M3)之光學直徑DPM 仍維持相對小,可引導投影光束通過面鏡而無漸暈。小型的光瞳鏡尺寸係由第一透鏡組LG1(做為為了於P1形成第一瞳之傅立葉透鏡組)強的正向強度以及接續之面鏡M1及M2之正向強度所構成,使可於光瞳鏡獲得主要光束角度CRAPM ≒45°。換言之,於光瞳鏡之主要光束角度係進一步隨著逐漸增加之NA而被增加,其中,根據拉格朗不變量,逐漸增加之NA可保持小的光瞳鏡尺寸。In the embodiment shown in Fig. 1, the catadioptric first objective member of the first lens M1 comprising the mirror set MG creates a first intermediate image IMI1 located in the space between the mirror and the mirror in the mirror. The second, third and fourth lenses M1 to M4 of the mirror set MG form a second, reflective imaging subsystem to form a second intermediate image IMI2 from the first intermediate image. The lens groups LG2, LG3, and LG4 constitute a third, refracting objective lens component for re-imaging the second intermediate image IMI2 on the image plane IS at a lower magnification (ratio of magnification ratio β = -0.125). It is obvious that the maximum lens diameter in the image waist portion between the compression portion CON and the image plane IS is improved relative to the system of the lower numerical aperture in FIG. 1, wherein the image waist close is located close to the first The aperture stop of the three-gloss plane P3 is AS. Invariably, the optical diameter D PM of the pupil mirror PM (third lens M3) remains relatively small, guiding the projection beam through the mirror without vignetting. The size of the small aperture mirror is composed of a strong positive intensity of the first lens group LG1 (as a Fourier lens group for forming the first pupil of P1) and a forward intensity of the mirrors M1 and M2. The main beam angle CRA PM ≒ 45° is obtained in the light mirror. In other words, the main beam angle of the pupil mirror is further increased with increasing NA, wherein the gradually increasing NA maintains a small pupil size according to the Lagrangian invariant.
光瞳鏡操作器PMM被提供來形變所欲改變之光瞳鏡反射面,如與圖3相關之敘述。The pupil mirror operator PMM is provided to deform the pupil mirror reflecting surface to be changed, as described in connection with FIG.
圖6顯示關於投影物鏡600之第三實施例,被設計供浸沒微影蝕刻於λ=193nm,於26*5.5 mm2 之環場具有像側數值孔徑NA=1.55,當被結合使用於高係數之浸沒液體,其具有折射係束n1 =1.65。最接近於場面IS之最後之光學元件係為以鎦鋁化合之石榴石做成之平凸透鏡PCL,具有折射係數n=2.14於λ=193nm。浸沒液體係為係數n1 =1.65之環已烷(cyclohexan)。規格係如表格6以及表格6A所述。此例中顯示一極高之數值孔徑可於在光軸上有光瞳鏡PM(面鏡M3)之線內系統中被獲得。靠近於像端第三光瞳面P3之孔徑光闌AS係置於有強大之聚合光束的區域,在第四透鏡組LG4中最大光束直徑之區域與像面IS之間。雖然,相對於圖1所示之實施例,像側數值孔徑急遽地增加,光瞳鏡PM的大小仍保持適中,而其係部分歸因於在第二光瞳面P2上大的主要光束角度CRAPM ≒36°。並且,藉由一拱狀有效物場OF(環形場),漸暈控制更容易被達成。Figure 6 shows a third embodiment of the projection objective 600 designed to be immersed in lithography at λ = 193 nm, with an image side numerical aperture NA = 1.55 in a ring field of 26 * 5.5 mm 2 when used in combination with high coefficients. The immersion liquid has a refractive beam n 1 = 1.65. The optical element closest to the scene IS is a plano-convex lens PCL made of yttrium-aluminum garnet having a refractive index n = 2.14 at λ = 193 nm. The immersion liquid system is a cyclohexan having a coefficient n 1 = 1.65. The specifications are as described in Table 6 and Table 6A. In this example, a very high numerical aperture is shown in an in-line system with a pupil PM (mirror M3) on the optical axis. The aperture stop AS adjacent to the image-side third pupil plane P3 is placed in a region having a strong converged beam between the region of the maximum beam diameter and the image plane IS in the fourth lens group LG4. Although, with respect to the embodiment shown in FIG. 1, the image side numerical aperture increases sharply, the size of the pupil mirror PM remains moderate, and the system is partially attributed to the large main beam angle on the second pupil plane P2. CRA PM ≒ 36°. Moreover, vignetting control is more easily achieved by an arched effective object field OF (ring field).
在以上所述之所有實施例中,使用具有可提供四個反射之軸向壓縮鏡組的線內反射折射物鏡,而第三鏡片置於瞳所在之位置以供做光瞳鏡(若需要,其可被操作)。於凹透鏡之至少兩個反射光學上往上行進至光瞳鏡,被認為對在光瞳鏡之位置上獲得高的主要光束角度CRAPM 較為有利,如此小尺寸的瞳以及小尺寸的光瞳鏡可以達成。小尺寸之光瞳鏡,因此,可使高孔徑之投影光束導引通過壓縮鏡組於相當小之物場中有相當大之有效物場,而無漸暈產生。In all of the embodiments described above, an in-line reflective refractive objective having an axially compressed mirror set that provides four reflections is used, and a third lens is placed in the position of the crucible for use as a pupil mirror (if needed, It can be operated). It is considered advantageous to obtain a high main beam angle CRA PM at the position of the pupil mirror by optically moving up to at least two reflections of the concave lens to the pupil mirror, such a small size crucible and a small aperture mirror Can be achieved. A small-sized aperture mirror, therefore, allows a high-aperture projection beam to be directed through a compression mirror in a relatively small object field with a substantial effective object field without vignetting.
圖8和圖9顯示反射折射線內投影物鏡之替代之實施例,反射折射線內投影物鏡具有可提供四個反射之軸向壓縮鏡組,且提供至少一光瞳鏡,其可能被用做為可動態控制的校正元件以控制像差。8 and 9 show an alternative embodiment of a projection objective in a spectroscopic line having an axially compressed mirror that provides four reflections and providing at least one aperture mirror, which may be used It is a dynamically controllable correction element to control aberrations.
如上所述圖1至圖6所示之實施例中,鏡組入口MGI之位置係接近光瞳面P1(第一光瞳面),然而鏡組出口MGO係位於光學上接近第二中間影像IMI2之位置,其係位於與光軸OA相分離之區域。光瞳鏡被提供在鏡組中之第三反射。In the embodiment shown in FIGS. 1 to 6 as described above, the position of the mirror group entrance MGI is close to the pupil plane P1 (first pupil plane), whereas the mirror group exit MGO is optically close to the second intermediate image IMI2. The position is located in a region separated from the optical axis OA. The pupil mirror is provided with a third reflection in the mirror.
於圖7之實施例中,鏡組MG被設置如此鏡組入口MGI係位於光軸OA之外的位置,且光學是接近於物面OS,例如,光學上接近場面。在物面和鏡組入口MGI之間沒有透鏡或透鏡組,然而,一或更多個透鏡可能於此被提供。第一凸面鏡M1形成第一光學元件且使輻射朝第二鏡片M2聚合,第二鏡片M2係為位於光軸OA上之光瞳鏡。第三鏡片M3將輻射聚合以形成第一中間影像IMI1,位於鏡組之反射折射凹點之內。反射折射之次系統包含第四鏡片M4導引輻射光束穿過位於第二光瞳面P2之鏡組出口MGO。第二中間影像IMI2被形成於鏡組之外,且於正向透鏡組之間(以箭頭朝外之箭號表示)。接續之折射第三物鏡部件將第二中間影像再次成像於像面。此實施例中,相較於先前之實施例,鏡組中的面鏡基本上以反向順序被利用。此設計要求有效物場被置於遠離光軸之處,其可增加所設計之物場的直徑,如此,投影高數值孔徑之相當大之物場而沒有漸暈會更加困難。In the embodiment of Fig. 7, the mirror set MG is arranged such that the mirror set entrance MGI is located outside the optical axis OA, and the optical is close to the object plane OS, for example, optically close to the scene. There are no lenses or groups of lenses between the object face and the mirror set entrance MGI, however, one or more lenses may be provided here. The first convex mirror M1 forms a first optical element and polymerizes the radiation toward the second lens M2, which is a pupil mirror located on the optical axis OA. The third lens M3 polymerizes the radiation to form a first intermediate image IMI1 that is located within the catadioptric recess of the mirror. The catadioptric secondary system includes a fourth lens M4 that directs the radiation beam through the mirror exit MGO at the second pupil face P2. The second intermediate image IMI2 is formed outside the mirror group and between the forward lens groups (indicated by arrows with arrows pointing outward). The refracting third objective lens component re-images the second intermediate image onto the image plane. In this embodiment, the mirrors in the mirror are utilized substantially in reverse order as compared to the previous embodiments. This design requires that the effective object field be placed away from the optical axis, which increases the diameter of the designed object field, so that it is more difficult to project a relatively large object field of high numerical aperture without vignetting.
如圖8所圖示之實施例,鏡組入口MGI以及鏡組出口MGO皆被置於光學上接近像面(也就是光學上遠離光瞳面)之位置,且於光軸OA之外。置於鏡組入口往上行進之折射元件將輻射聚合朝第一鏡片M1進行,第一鏡片M1係為第一光瞳鏡PM1。第二瞳被形成於第二鏡片M2及第三鏡片M3之反射於第四鏡片M4的位置之後,第四鏡片M4係為第二光瞳鏡PM2。第一中間影像IMI1被形成於第二及第三折射之間,第二中間影像IMI2被形成於第四反射往下行進之處,如此兩者中間成像皆被置於面鏡及鏡組之表面曲率所定義的空間之中。第二中間影像IMI2藉由接續之折射透鏡組,被再次成像於像面。不論第一鏡片M1或第四鏡片M4或兩者,第一以及第四鏡片可能被設計為適應性面鏡,以操作光瞳鏡表面之形狀而動態補償系統中之成像誤差。依照既定的物體高度,在第一光瞳鏡PM1以及在第二光瞳鏡PM2上很難獲得大的主要光束角度,如此,隨著像側數值孔徑之增加,光瞳鏡的尺寸將會有顯著的增加。此效應可能限制在無漸暈之下傳送大的幾何通量的能力。並且,相對大之透鏡被要求立即向下行進至鏡組以捕捉發散光束射出鏡組出口MGO。此種系統較佳地以相對大幅度之縮小比值,例如,以8:1替代4:1,由於相對於具有較小幅度之縮小比值(例如4:1)的系統,物端之數值孔徑以及物場高度可被減小。As with the embodiment illustrated in Figure 8, both the mirror inlet MGI and the mirror outlet MGO are placed optically near the image plane (i.e., optically away from the pupil plane) and outside of the optical axis OA. The refractive element placed upstream of the entrance of the mirror group radiates radiation toward the first lens M1, which is the first aperture mirror PM1. The second aperture M4 is formed as a second aperture mirror PM2 after the second lens M2 and the third lens M3 are reflected at the position of the fourth lens M4. The first intermediate image IMI1 is formed between the second and third refractions, and the second intermediate image IMI2 is formed at a position where the fourth reflection goes downward, so that the intermediate images are placed on the surface of the mirror and the mirror. Among the spaces defined by curvature. The second intermediate image IMI2 is imaged again on the image plane by the subsequent refractive lens group. Regardless of the first lens M1 or the fourth lens M4 or both, the first and fourth lenses may be designed as an adaptive mirror to dynamically compensate for imaging errors in the system by operating the shape of the pupil mirror surface. According to the height of the object, it is difficult to obtain a large main beam angle on the first aperture mirror PM1 and the second aperture mirror PM2. Thus, as the numerical aperture of the image side increases, the size of the aperture mirror will have Significant increase. This effect may limit the ability to transmit large geometric fluxes without vignetting. Also, a relatively large lens is required to immediately travel down to the mirror to capture the diverging beam exiting the mirror exit MGO. Such a system preferably has a relatively large reduction ratio, for example, 4:1 instead of 4:1, due to the numerical aperture of the object end relative to a system having a smaller magnitude reduction ratio (eg 4:1) The height of the object field can be reduced.
圖9圖示做為晶圓掃瞄器WS之微影投影曝光系統,其被提供做為製造大尺寸之積體整合半導體元件,使用浸沒微影之步進掃瞄模式。投影曝光系統包含做為光源且具有193nm之操作波長的準分子雷射L。其他操作波長,例如157nm或248nm,也有可能被使用。下行之照明系統ILL在其光出口表面ES中產生大而有銳利界限之同質照明之照明場,其被設置於偏離投影物鏡PO之光軸之位置,且調適於下行之反射折射投影物鏡PO之遠心條件。照明系統ILL擁有選擇照明模式的裝置,此例中,照明系統ILL可在具有可變關連程度之傳統軸上照明以及離軸照明之間被改變,尤其是環狀照明(於照明系統中之光瞳表面具有環形之照明區域)以及二極或四極管照明。Figure 9 illustrates a lithographic projection exposure system as a wafer scanner WS that is provided as a step-by-step scanning mode using immersion lithography to fabricate large-sized integrated semiconductor components. The projection exposure system includes a quasi-molecular laser L that acts as a light source and has an operating wavelength of 193 nm. Other operating wavelengths, such as 157 nm or 248 nm, may also be used. The descending illumination system ILL produces a large, sharply bound, homogeneous illumination illumination field in its light exit surface ES, which is disposed at a position offset from the optical axis of the projection objective PO and adapted to the downward reflective refractive index objective lens PO. Telecentric conditions. The lighting system ILL has a device for selecting a lighting mode, in which case the lighting system ILL can be changed between conventional on-axis illumination with off-axis illumination and off-axis illumination, especially ring illumination (light in the illumination system) The surface of the crucible has a circular illumination area) and bipolar or quadrupole illumination.
被設置於照明系統下行方向之裝置為光柵台裝置RS(reticle stage,光柵台),用以承托以及操作光罩M,其方式係將光罩置於與物面OS相一致的照明系統之光出口表面ES,且在此平面上,光罩可被移動以在掃瞄方向上(Y方相)進行掃瞄;掃瞄方向垂直於光軸OA,光軸OA與照明系統及投影物鏡位於同方向(也就是Z方向)。The device disposed in the downward direction of the illumination system is a reticle stage RS for supporting and operating the reticle M by placing the reticle in an illumination system conforming to the object surface OS. The light exit surface ES, and in this plane, the reticle can be moved to scan in the scanning direction (Y-phase); the scanning direction is perpendicular to the optical axis OA, and the optical axis OA is located in the illumination system and the projection objective The same direction (that is, the Z direction).
照明系統所提供之照明場IF之尺寸及形狀,決定投影物鏡之有效物場OF的尺寸及形狀,此投影物鏡實際上被供做投影光罩之圖案影像於投影物鏡之像面。具縱切形狀之照明場IF在平行於掃瞄方向上具有高度A,以及,在掃瞄方向之垂直方向上具有寬度B>A,而照明場IF可能為矩形(如圖所示)或為拱狀(環形場)。The size and shape of the illumination field IF provided by the illumination system determines the size and shape of the effective object field OF of the projection objective. The projection objective is actually used as a pattern image of the projection mask on the image surface of the projection objective. The illumination field IF having a slit shape has a height A parallel to the scanning direction, and has a width B>A in the vertical direction of the scanning direction, and the illumination field IF may be rectangular (as shown) or Arched (ring field).
縮小的投影物鏡OP在物端及像端係為遠心,以及被設計將具有縮小比值4:1之光罩所提供之圖案影像成像於塗佈光阻層之晶圓W。其他縮小比值,例如5:1或8:1也有可能。做為光敏基板之晶圓W被設置使得塗有光阻層之平面基板表面SS實質上與投影物鏡之平面像面IS相一致。承托晶圓之裝置WS(晶圓台)包含掃瞄驅動器,為了使晶圓與光罩M同步且平行地移動。裝置WS另包含操作器,為了使晶圓移動於與光軸OA平行之Z方向以及移動於與光軸垂直之X方向與Y方向。一傾斜裝置被整合於此,此傾斜裝置具有垂直繞行光軸之至少一傾斜軸。The reduced projection objective OP is telecentric at the object end and the image end, and is designed to image a pattern image provided by a photomask having a reduction ratio of 4:1 on the wafer W coated with the photoresist layer. Other reduction ratios, such as 5:1 or 8:1, are also possible. The wafer W as a photosensitive substrate is disposed such that the planar substrate surface SS coated with the photoresist layer substantially coincides with the planar image plane IS of the projection objective. The wafer-supporting device WS (wafer stage) includes a scan driver for moving the wafer in synchronization with the mask M and in parallel. The device WS further includes an operator for moving the wafer in the Z direction parallel to the optical axis OA and in the X direction and the Y direction perpendicular to the optical axis. A tilting device is integrated therewith, the tilting device having at least one tilting axis that vertically circumscribes the optical axis.
供承托晶圓W之裝置WS被建構供做為浸沒微影。此裝置包含容納裝置RD,其可被掃瞄驅動器移動,且其底部有扁平凹處以容納晶圓W。一周圍之邊緣形成扁平,開口向上,且防止液體漏出之容納處,其容納液體浸沒介質IM,液體可被導入容納處且可被某一未圖示之裝置導出於容納處。邊緣高度的大小被設計為使填充之浸沒介質可完全覆蓋水W的表面SS,且投影物鏡PO之出口面的端部區域可沾到浸沒液體,若正確設定物鏡出口以及晶圓表面之操作距離。The device WS for supporting the wafer W is constructed for immersion lithography. This device includes a receiving device RD that is movable by the scan driver and has a flat recess at the bottom to accommodate the wafer W. A peripheral edge forms a flat, open-ended, and containment reservoir that prevents liquid from escaping, which contains liquid immersion medium IM, which can be directed into the receptacle and can be directed to the receptacle by a device not shown. The height of the edge is designed such that the filled immersion medium can completely cover the surface SS of the water W, and the end region of the exit surface of the projection objective lens PO can be immersed in the immersion liquid, if the objective lens exit and the operating distance of the wafer surface are correctly set .
投影物鏡PO有平凸透鏡PCL做為最靠近像面IS之最後光學元件,此透鏡之平面出口表面係為投影物鏡PO之最後光學表面。在投影曝光系統之操作期間,最後光學元件之出口表面係完全地浸沒於浸沒液體IM之中,且被浸濕。此例中,具有折射係數nI ≒1.437(193nm)之極純水係做為浸沒液體。The projection objective lens PO has a plano-convex lens PCL as the last optical element closest to the image plane IS, and the plane exit surface of the lens is the last optical surface of the projection objective lens PO. During operation of the projection exposure system, the exit surface of the final optical element is completely submerged in the immersion liquid IM and is wetted. In this example, an ultrapure water system having a refractive index n I ≒ 1.437 (193 nm) was used as the immersion liquid.
溫度感測器SENS被供來監視在投影曝光系統操作期間之浸沒液體IM的溫度。以此目的,依溫度變化反應之一感測元件被置於靠近投影物鏡PO之出口表面的位置,以監視在曝光時被輻射傳導的浸沒層的溫度。溫度感測器係連接於曝光系統之中央控制單元,其包括供控制投影物鏡PO之光瞳鏡反射表面的形狀之光瞳鏡控制單元PMCU,其使用光瞳鏡操作器PMM(例如比較於圖3)。光瞳鏡控制單元PMCU包含數位儲存器,其包含查找表格,用來將溫度感測器提供之溫度訊號轉換至一數值,此數值係供做浸沒層的浸沒液體之折射係數。浸沒層之溫度在曝光時變化,可能基於以下原因:因吸收投影光束的輻射強度(溫度增加),或,因新的浸沒液體流入投影物鏡出口表面與晶圓之間的空間內(溫度增加或減少),而使浸沒層之折射係數產生波動。這些可能造成場不變導致球面像差,影響晶圓上影像之形成。這些於像端之遠心投影系統之操作特性的波動被補償,藉由調整光瞳鏡之反射形狀,如此,對應之球面像差數量被傳給光瞳鏡以補償浸沒層對球面像差之影響。利用此控制迴圈,穩定的浸沒微影製程可被達成。A temperature sensor SENS is provided to monitor the temperature of the immersion liquid IM during operation of the projection exposure system. For this purpose, one of the sensing elements in response to the temperature change is placed close to the exit surface of the projection objective PO to monitor the temperature of the immersion layer that is radiated while exposed. The temperature sensor is coupled to a central control unit of the exposure system that includes a pupil mirror control unit PMCU for controlling the shape of the pupil mirror reflective surface of the projection objective PO, using a pupil mirror operator PMM (eg, compared to a map) 3). The pupil mirror control unit PMCU comprises a digital memory comprising a lookup table for converting the temperature signal provided by the temperature sensor to a value which is the refractive index of the immersion liquid for the immersion layer. The temperature of the immersion layer changes during exposure, possibly for the following reasons: by absorbing the radiation intensity of the projected beam (increased temperature), or because the new immersion liquid flows into the space between the exit surface of the projection objective and the wafer (temperature increases or Reduce), and the refractive index of the immersion layer fluctuates. These may cause the field to change and cause spherical aberration, which affects the formation of images on the wafer. The fluctuations in the operational characteristics of these telecentric projection systems at the image end are compensated by adjusting the reflection shape of the pupil mirror. Thus, the corresponding spherical aberration amount is transmitted to the pupil mirror to compensate for the influence of the immersion layer on the spherical aberration. . With this control loop, a stable immersion lithography process can be achieved.
光瞳鏡控制單元PMCU仍被設定來接收照明系統ILL之信號,其係代表於曝光中所用之照明設定,且控制單元PMCU包含控制慣常程序,允許對光瞳鏡表面進行調整,對應於被選擇之照明設定。例如,被投影在晶圓上之光罩圖案實質上包括於同一方向上行進之平行線,雙極設定DIP(請見圖示)可被用來增加解析度以及聚焦深度。為此目的,照明系統中之可調整光學元件被調整以在照明系統ILL之光瞳表面PS取得強度分佈,此強度分佈之特徵在於具有兩個局部集中照明的區域IR,具有大光線強度的兩區域係位於光軸OA之外相對立之相反位置之上,且,在光軸上之光線強度很小或甚至為零。相似之非均質強度分佈在投影物鏡之光瞳面中被取得,此光瞳面與照明係同之光瞳面光學上相成對。因此,分別靠近於或在上述之投影物鏡之第一或第三光瞳表面P1,P3之透鏡可能遭受空間中不同質之輻射負載,其特點是在光軸外相對立之兩個區域有兩個「熱區」,此可能導致局部因吸收而產生之透鏡加熱,造成特徵透鏡之形變以及折射係數之變異,此造成波形之特徵形變,其特點在於實質上徑向對稱於光軸之兩邊。The pupil mirror control unit PMCU is still set to receive the signal of the illumination system ILL, which represents the illumination setting used in the exposure, and the control unit PMCU contains a control routine that allows adjustment of the pupil mirror surface, corresponding to the selection Lighting settings. For example, the reticle pattern projected onto the wafer essentially includes parallel lines that travel in the same direction, and a bipolar set DIP (see illustration) can be used to increase resolution and depth of focus. For this purpose, the adjustable optical element in the illumination system is adjusted to obtain an intensity distribution at the pupil surface PS of the illumination system ILL, characterized by a region IR having two locally concentrated illuminations, two having a large light intensity The region is located opposite the opposite position outside the optical axis OA, and the intensity of the light on the optical axis is small or even zero. A similar heterogeneous intensity distribution is obtained in the pupil plane of the projection objective, which is optically paired with the pupil plane of the illumination system. Therefore, the lenses of the first or third pupil surfaces P1, P3 respectively adjacent to or at the above-mentioned projection objective lens may be subjected to different qualitative radiation loads in the space, which are characterized by two opposite regions in the opposite direction of the optical axis. "Hot zone", which may cause local lens heating due to absorption, causing deformation of the characteristic lens and variation of refractive index, which causes characteristic deformation of the waveform, which is characterized by substantially radial symmetry to both sides of the optical axis.
光瞳鏡表面恰當的操作可被用來補償這些效應,藉由提供在光瞳鏡表面上適當的形變,在正確之方向上徑向對稱於光軸之兩邊。Proper operation of the pupil mirror surface can be used to compensate for these effects by providing a suitable deformation on the pupil mirror surface that is radially symmetric about both sides of the optical axis in the correct direction.
若照明設定被改變來獲得,例如,一般之照明(旋轉對稱於光軸)或四極管照明(徑向對稱於光軸之四邊,請見圖中右手邊之小圖QUAD,具有四個離軸照明區域IR),而光瞳鏡操作單元將提供相對應之信號至光瞳鏡操作器,以依照改變光瞳鏡之表面形狀。If the illumination setting is changed to obtain, for example, general illumination (rotational symmetry to the optical axis) or quadrupole illumination (radial symmetry to the four sides of the optical axis, please see the right hand thumbnail QUAD in the figure, with four off-axis The illumination area IR), and the light mirror operating unit will provide a corresponding signal to the pupil mirror operator to change the surface shape of the aperture mirror.
可選擇性地提供以上所述之離軸極之照明模式之照明系統被描述於如美國專利號US 6,252,647 B1之中,或於申請人之美國專利申請案號US 2006/005026 A1之中,上述揭露內容係被併入本申請案作為參考。對照明設定之光瞳鏡之適應化設定可被用於浸沒系統,例如以上所述之實施例,或者也可被用於乾式系統,也就是說,使用NA<1之乾式物鏡之系統。An illumination system that selectively provides an off-axis illumination mode as described above is described in, for example, U.S. Patent No. 6,252,647 B1, or in the U.S. Patent Application Serial No. US 2006/005026 A1, which is incorporated herein by reference. The disclosure is incorporated herein by reference. The adaptation of the illumination setting optics can be used in an immersion system, such as the embodiments described above, or can also be used in a dry system, that is, a system using a dry objective of NA < 1.
在其他實施例中(未圖示),被提供來形變光瞳鏡之反射表面之光瞳鏡操作器控制訊號,係來自於光瞳鏡控制單元中所儲存之控制參數的經驗值或運算值。在這些實施例中,對投影系統之成像特性的直接或間接量測並非必要。In other embodiments (not shown), the optical mirror operator control signal provided to deform the reflective surface of the pupil mirror is an empirical or operational value from a control parameter stored in the pupil mirror control unit. . In these embodiments, direct or indirect measurement of the imaging characteristics of the projection system is not necessary.
進一步而言,具有凹光瞳鏡之反射折射投影物鏡以及控制光瞳鏡之反射表面形狀的控制系統將於下詳述並配合圖10以及圖11。Further, a catadioptric projection objective having a concave pupil mirror and a control system for controlling the shape of the reflective surface of the pupil mirror will be described in detail below with reference to FIGS. 10 and 11.
圖10圖示反射折射投影物鏡1000被設計為名義上紫外線操作波長λ=193nm。此例之投影物鏡的佈局,有關於透鏡之數量、形狀以及位置,以及其他光學元件係取自圖4所示之投影物鏡,且在歐洲專利EP 1 069 448 B1之第二實施例(表格2)中被討論。以上參考資料之揭露內容係被併入本申請案作為參考。投影物鏡係適用於「乾式微影」,在投影物鏡之出口表面與像面之間具有充滿氣體之空間。在具有縮小比6:1(|β|=1/6)之拱形離軸像場中,可得到像端之數值孔徑NA=0.75。其他實施例中可能有不同之放大比率,例如|β|=1/5或|β|=1/4,或|β|=1(單位放大)。Figure 10 illustrates that the catadioptric projection objective 1000 is designed to nominally operate at a wavelength of λ = 193 nm. The layout of the projection objective of this example, relating to the number, shape and position of the lenses, and other optical components are taken from the projection objective shown in Fig. 4, and in the second embodiment of the European patent EP 1 069 448 B1 (Table 2 ) is discussed. The disclosure of the above references is incorporated herein by reference. The projection objective system is suitable for "dry lithography", and has a space filled with gas between the exit surface of the projection objective and the image plane. In the arched off-axis image field with a reduction ratio of 6:1 (|β| = 1/6), the numerical aperture NA = 0.75 of the image end can be obtained. Other embodiments may have different magnification ratios, such as |β|=1/5 or |β|=1/4, or |β|=1 (unit magnification).
投影物鏡1000可被設定來將被設置於平面物面OS(物平面)之光罩圖案之影像投影於平面像面IS(像平面),當產生相同之真實中間影像IMI。第一反射折射物鏡部件OP1被設計對來自物面之圖案成像於中間影像IMI。純反射第二物鏡部件OP2將中間影像直接成像於像面(也就是沒有進一步之中間影像)。兩個共軛之光瞳表面P1及P2形成於CR交會於光軸OA之處。第一光瞳表面P1被形成於第一物鏡部件,而第二光瞳表面被形成於第二物鏡部件OP2。當第一物鏡部件OP1僅有中等的縮小效應,主要的縮小係來自第二折射物鏡部件OP2之貢獻。所有光學元件係沿單一且筆直之光軸OA排列,以使物面OS及像面IS平行設置。投影物鏡之瞳出口係實質上為環形。第一凹鏡M1係置於相當接近於第一光瞳面P1之位置,因而形成光瞳鏡PM。The projection objective 1000 can be set to project an image of the reticle pattern set on the plane object plane OS (object plane) onto the plane image plane IS (image plane) when the same real intermediate image IMI is produced. The first catadioptric objective element OP1 is designed to image the pattern from the object surface to the intermediate image IMI. The purely reflective second objective lens component OP2 images the intermediate image directly onto the image plane (ie, without further intermediate images). Two conjugated pupil surfaces P1 and P2 are formed where the CR intersects at the optical axis OA. The first pupil surface P1 is formed on the first objective lens member, and the second pupil surface is formed on the second objective lens member OP2. When the first objective lens part OP1 has only a moderate reduction effect, the main reduction is due to the contribution of the second refractive objective lens part OP2. All of the optical elements are arranged along a single, straight optical axis OA such that the object plane OS and the image plane IS are arranged in parallel. The exit of the projection objective is substantially annular. The first concave mirror M1 is placed at a position relatively close to the first pupil plane P1, thus forming the pupil mirror PM.
第一物鏡部件OP1具有以兩個正向彎月形透鏡所形成之正向透鏡組LG1,以單一雙凹負鏡所形成之負鏡組LG2,具有面對物面之反射面之第一凹面鏡M1,其立即往下行進至負鏡組LG2,以及,具有面對第一凹面鏡以及像面之第二凹面鏡M2。第二物鏡部件OP2具有以單一正向透鏡所組成之正向透鏡組LG3,以及以單一雙凹負鏡組成之負鏡組LG4,以及,於第二光瞳面P2與像面之間具有五個正向透鏡以及兩個負鏡之正向透鏡組LG5。允許調整被使用之像側數值孔徑NA之可變孔徑光闌AS係置於第二光瞳面與第四及第五透鏡組之間。The first objective lens part OP1 has a forward lens group LG1 formed by two positive meniscus lenses, and a negative lens group LG2 formed by a single double concave negative mirror, having a first reflecting surface facing the object surface The concave mirror M1 immediately travels down to the negative lens group LG2, and has a second concave mirror M2 facing the first concave mirror and the image surface. The second objective lens part OP2 has a forward lens group LG3 composed of a single forward lens, and a negative lens group LG4 composed of a single double concave negative mirror, and between the second pupil plane P2 and the image plane Five forward lenses and two negative mirror positive lens groups LG5. A variable aperture stop AS that allows adjustment of the image side numerical aperture NA used is placed between the second pupil face and the fourth and fifth lens groups.
來自物面之輻射係被正向第一透鏡組LG1朝第一凹面鏡M1聚合,且被第一凹面鏡反射至第二凹面鏡M2,其將輻射聚合以形成第一中間影像。被導引朝向以及反射自第一凹面鏡M1之輻射,以相反方向通過負鏡組LG2兩次。第一凹面鏡M1之反射面以及負鏡組LG2兩者在光學上皆位於很接近第二光瞳面P2之位置,此位置係為輻射光束之切面僅與環形有些微相異之處,以及,此位置係為邊緣光束高度係至少大於主要光束高度4倍至5倍之處。相當靠近光瞳面之凹面鏡M1以及與其共軸且被輻射通過兩次之負鏡組LG2相結合,以「Schupmann消色差」(Schupmann achromat)之方式支持校正色差,特別是對軸向色差之校正。第二物鏡部件OP2將中間影像IMI1再次成像以在像面IS中形成最終影像。The radiation from the object plane is polymerized toward the first concave mirror M1 by the forward first lens group LG1 and is reflected by the first concave mirror to the second concave mirror M2, which polymerizes the radiation to form a first intermediate image. The radiation directed toward and reflected from the first concave mirror M1 passes through the negative mirror group LG2 twice in the opposite direction. Both the reflecting surface of the first concave mirror M1 and the negative mirror group LG2 are optically located very close to the second pupil plane P2, and the position is that the section of the radiation beam is only slightly different from the ring shape, and This position is where the edge beam height is at least 4 to 5 times greater than the main beam height. The concave mirror M1, which is close to the pupil plane, and the negative mirror group LG2, which is coaxial with the radiation and passed through twice, support the correction of the chromatic aberration, especially the correction of the axial chromatic aberration, in the manner of "Schupmann achromat" (Schupmann achromat) . The second objective lens part OP2 re-images the intermediate image IMI1 to form a final image in the image plane IS.
裝設在光瞳鏡PM(M1)背後之光瞳鏡操作器PMM被設定來改變光瞳鏡之非球面反射表面的形狀,藉由適當的觸發器(未圖示)。一般光瞳鏡操作器之設計可能與圖3所述之光瞳鏡操作器相同或不同。觸發器被光瞳鏡控制單元PMCU所控制,控制單元可能整合於投影曝光裝置之中央控制單元之中。光瞳鏡控制單元被設定來產生控制訊號使光瞳鏡操作器之觸發器可調整光瞳鏡表面形狀,如此所欲達成之形狀可被達成。The pupil mirror operator PMM mounted behind the pupil mirror PM (M1) is set to change the shape of the aspherical reflective surface of the pupil mirror by a suitable trigger (not shown). The design of a typical pupil mirror operator may be the same or different than the diaphragm operator described in FIG. The trigger is controlled by the pupil mirror control unit PMCU, which may be integrated into the central control unit of the projection exposure unit. The pupil mirror control unit is configured to generate a control signal such that the trigger of the pupil mirror operator can adjust the shape of the pupil mirror surface such that the desired shape can be achieved.
光瞳鏡控制單元PMCU係連接於第一感測器SENS1以及第二感測器SENS2。第一感測器SENS1係整合於一量測系統,例如干涉計,使可偵測操作中之投影物鏡的成像品質,且可提供可指示光學效能之量測值的訊號。例如,第一感測器SENS1可被設定來偵測入射於像面之波前的波前像差。適用於此目的之波前量測系統之例子可見於如美國專利申請案US 2002/0001088 A1,其揭露內容係被併入本申請案作為參考。第二感測器SENS2被設定來獲得指示孔徑光闌之目前狀態的訊號,如此可得到,例如,目前使用於過程之像側數值孔徑NA。選擇性地,或額外地,第二感測器可被提供來得到指示光瞳面之強度或強度分佈之訊號,或指示在光瞳面中及/或在投影物鏡之場面之波前特徵的訊號。The pupil mirror control unit PMCU is connected to the first sensor SENS1 and the second sensor SENS2. The first sensor SENS1 is integrated into a measurement system, such as an interferometer, to detect the imaging quality of the projection objective in operation, and to provide a signal indicative of the measurement of the optical performance. For example, the first sensor SENS1 can be set to detect wavefront aberrations incident on the wavefront of the image plane. An example of a wavefront measurement system suitable for this purpose can be found in, for example, U.S. Patent Application Serial No. US 2002/0001088 A1, the disclosure of which is incorporated herein by reference. The second sensor SENS2 is set to obtain a signal indicative of the current state of the aperture stop, as may be obtained, for example, from the image side numerical aperture NA currently used in the process. Alternatively, or additionally, the second sensor can be provided to obtain a signal indicative of the intensity or intensity distribution of the pupil plane, or to indicate the wavefront features of the scene in the pupil plane and/or at the projection objective. Signal.
在具有更多中間成像之實施例中,例如兩個中間成像且/或在折疊系統中,類似之控制電路可被提供。In embodiments with more intermediate imaging, such as two intermediate imaging and/or in a folding system, similar control circuitry can be provided.
圖11顯示反射折射投影物鏡1100。投影物鏡係被設計為名義上紫外線操作波長λ=193nm。此例之投影物鏡的佈局,有關於透鏡之數量、形狀以及位置,以及其他光學元件係取自圖9所示之投影物鏡,且在國際專利申請案WO 2004/019128 A2之第五個實施例中(表格9及10)被討論。以上參考資料之揭露內容係被併入本申請案作為參考。在具有縮小比4:1,且尺寸為26mm*4mm之矩形離軸像場中,可得到像側數值孔徑NA=1.25。FIG. 11 shows a catadioptric projection objective 1100. The projection objective system is designed to nominally operate at a wavelength of λ = 193 nm. The layout of the projection objective of this example, relating to the number, shape and position of the lenses, and other optical components are taken from the projection objective shown in FIG. 9, and in the fifth embodiment of the international patent application WO 2004/019128 A2 Medium (Tables 9 and 10) are discussed. The disclosure of the above references is incorporated herein by reference. In a rectangular off-axis image field having a reduction ratio of 4:1 and a size of 26 mm * 4 mm, an image side numerical aperture NA = 1.25 can be obtained.
投影物鏡1100被設計來將被設置於平面物面OS(物平面)之光罩(柵)之圖案之影像投影於較小尺寸之平面像面IS(像平面),例如,4:1,當產生兩個相同且真實之中間影像IMI1,IMI2。矩形有效物場OF以及像場IF皆為離軸,也就是,完全在光軸OA之外。第一折射物鏡部件OP1被設計來將物面之圖案成像於第一中間影像IMI1。反射折射之第二物鏡部件OP2將第一中間影像IMI1以接近於1:(-1)之放大率成像於第二中間影像IMI2。折射之第三物鏡部件OP3將第二中間影像IMI2以很大之縮小率成像於像面IS。The projection objective lens 1100 is designed to project an image of a pattern of a mask (gate) provided on a plane object plane OS (object plane) onto a plane image surface IS (image plane) of a smaller size, for example, 4:1, when Two identical and realistic intermediate images IMI1, IMI2 are generated. The rectangular effective object field OF and the image field IF are off-axis, that is, completely outside the optical axis OA. The first refractive objective lens part OP1 is designed to image the pattern of the object surface on the first intermediate image IMI1. The catadioptric second objective lens part OP2 images the first intermediate image IMI1 at a magnification close to 1: (-1) to the second intermediate image IMI2. The refracted third objective lens part OP3 images the second intermediate image IMI2 at a large reduction ratio on the image plane IS.
三個相互共軛之光瞳面P1,P2以及P3係形成於主要光束CR交會於光軸之位置。第一光瞳面P1係形成於第一物鏡部件,介於物面及第一中間影像之間;第二光瞳面P2係形成於第二物鏡部件,介於第一和第二中間影像之間;以及,第三光瞳面P3係形成於第三物鏡部件,介於第二中間影像和像面IS之間。Three mutually conjugated pupil planes P1, P2, and P3 are formed at positions where the main beam CR intersects the optical axis. The first pupil plane P1 is formed on the first objective lens member between the object surface and the first intermediate image; the second pupil plane P2 is formed on the second objective lens component, and is interposed between the first and second intermediate images. And a third pupil plane P3 is formed on the third objective lens member between the second intermediate image and the image plane IS.
第二物鏡部件OP2於第二光瞳面P2包含單一凹面鏡CM,如此形成光瞳鏡PM。第一平面折疊鏡FM1被設置於光學上接近第一中間影像IMI1且與光軸OA相夾45°之位置,如此第一平面折疊鏡FM1反射來自物面之輻射以往凹面鏡CM之方向前進。第二重鏡FM2,具有平面鏡表面並排列於第一折疊鏡FM1右側一夾角之處,以折射來自凹面鏡CM之輻射(光瞳鏡M)以往像面前進,像面係平行於物面。折疊面鏡FM1,FM2分別位於光學上鄰近於中間影像之處。The second objective lens part OP2 includes a single concave mirror CM on the second pupil plane P2, thus forming the pupil mirror PM. The first plane folding mirror FM1 is disposed at a position optically close to the first intermediate image IMI1 and sandwiched by the optical axis OA by 45°, such that the first plane folding mirror FM1 reflects the direction from the object surface to the conventional concave mirror CM. The second heavy mirror FM2 has a plane mirror surface and is arranged at an angle on the right side of the first folding mirror FM1 to refract the radiation from the concave mirror CM (the optical mirror M) to advance the image surface, and the image plane is parallel to the object surface. The folding mirrors FM1, FM2 are respectively located optically adjacent to the intermediate image.
投影物鏡具有27個透鏡,包含兩個負向彎月形透鏡,立即在凹面鏡CM之前面組成負鏡組,以及其被輻射通過兩次,一次來自第一折疊鏡FM1朝向凹面鏡,一次來自凹面鏡朝向第二重鏡。位於光學上接近光瞳面之凹面鏡以及包含至少一個負鏡且位於凹面鏡反射面之前方(位於輻射可通過兩次之區域,兩次通過負鏡組之方向為相反)的負鏡組之組合有時被稱為「Schupmann消色差」(Schupmann achromat)。此透鏡組對色差校正有相當大的貢獻,特別是軸向色差校正。The projection objective has 27 lenses, including two negative meniscus lenses, which immediately form a negative mirror before the concave mirror CM, and it is radiated twice, once from the first folding mirror FM1 toward the concave mirror, once from the concave mirror Second heavy mirror. a combination of a concave mirror that is optically close to the pupil plane and a negative mirror group that includes at least one negative mirror and is located before the concave mirror reflecting surface (in the region where the radiation can pass twice and the direction through which the negative mirror passes twice) It is called "Schupmann achromat". This lens group has a considerable contribution to chromatic aberration correction, especially axial chromatic aberration correction.
光瞳鏡操作器PMM係提供於凹面鏡CM可自由接觸的背後。光瞳鏡操作器包含一些觸發器(以箭號表示)作用於有彈性的鏡面基板以連續改變反射表面的形狀以回應連接於光瞳鏡操作器PMM之光瞳鏡控制單元PMCU的控制訊號。第一感測器SENS1可操作地連接於彈性鏡面基板,以二維且高空間解析度的方式感測折射表面之形變的狀態。光瞳鏡控制單元係連接於感測器SENS1以接收回饋訊號,代表光瞳鏡表面實際上之形變狀態。光瞳鏡操作器以及對應之控制單元可被設計成實質上先前與圖3有關之描述。第一感測器SENS1可以是機電感測器,以接收依光瞳鏡之機構狀態所獲得之電訊號。選擇性地,或者另外地,監視凹面鏡形變之感測系統可依照美國專利US 6,784,977 B2中所指示之原則來設計。此專利相關之揭露內容被併入本申請案作為參考。The pupil mirror operator PMM is provided behind the concave mirror CM which is free to contact. The light mirror operator includes a trigger (indicated by an arrow) acting on the resilient mirror substrate to continuously change the shape of the reflective surface in response to the control signal of the pupil mirror control unit PMCU connected to the pupil mirror operator PMM. The first sensor SENS1 is operatively coupled to the elastic mirror substrate to sense the state of deformation of the refractive surface in a two-dimensional and high spatial resolution manner. The light mirror control unit is connected to the sensor SENS1 to receive the feedback signal, which represents the actual deformation state of the pupil mirror surface. The pupil mirror operator and corresponding control unit can be designed to be substantially as previously described in relation to FIG. The first sensor SENS1 may be a machine inductance detector to receive the electrical signal obtained by the state of the optical mirror. Alternatively, or in addition, the sensing system for monitoring the concave mirror deformation can be designed in accordance with the principles indicated in U.S. Patent No. 6,784,977 B2. The disclosure of this patent is incorporated herein by reference.
一般而言,由光瞳鏡形成之面鏡設置,以及用來對光瞳鏡反射表面的形狀做改變或形變之光瞳鏡操作器,可以先前描述之方法或者其他方法而被建構。例子可見於美國專利US 5,986,795或美國專利申請案US 2006/0018045 A1。此等專利相關之揭露內容被併入本申請案作為參考。In general, the mirror arrangement formed by the pupil mirror, and the aperture mirror operator used to change or deform the shape of the pupil mirror reflection surface, can be constructed by the methods previously described or by other methods. Examples are found in U.S. Patent No. 5,986,795 or U.S. Patent Application Serial No. US 2006/0018045 A1. The disclosures of these patents are incorporated herein by reference.
用來影響光瞳鏡反射表面之形變的光瞳鏡操作器之控制可以被各種方式設定,與物鏡種類(折疊或線內)以及中間影像之數量相獨立。The control of the pupil mirror operator used to affect the deformation of the reflective surface of the pupil mirror can be set in various ways, independent of the type of objective (folded or inline) and the number of intermediate images.
在一些實施例中,控制光瞳鏡操作器之控制系統包括控制電路被設定來接收至少一個輸入訊號,此輸入訊號指示投影物鏡或者投影曝光裝置的另一部分之至少一種狀況,以及,輸出控制訊號至光瞳鏡操作器,此控制訊號代表,回應輸入訊號,而對光瞳鏡之表面形狀的調整以調適投影物鏡之成像特性。控制電路可以開放式迴路控制之方式被操作。In some embodiments, the control system for controlling the mirror operator includes a control circuit configured to receive at least one input signal indicative of at least one condition of the projection objective or another portion of the projection exposure device, and outputting the control signal To the mirror operator, this control signal represents, in response to the input signal, the surface shape of the pupil mirror is adjusted to accommodate the imaging characteristics of the projection objective. The control circuit can be operated in an open loop control manner.
舉例而言,代表照明設定(例如,雙極或四極性照明)之輸入訊號可被接收自照明系統,且在控制電路中被處理以產生控制訊號,以使光瞳鏡操作器之觸發器將光瞳鏡之反射表面形變,以獲得具有二重或四重旋轉對稱之表面形變,如此,分別地,在照明之極部上可能會產生之非均質透鏡加熱之至少一部分可由不對稱之光瞳鏡表面形變補償。選擇性地,或額外地,其他之輸入訊號也可被產生或處理,例如,代表圖案種類之輸入訊號(例如線狀圖案、孔狀圖案,以及/或有不同方向線條之圖案),代表數值孔徑NA之輸入訊號,及/或,代表曝光次數之輸入訊號。For example, an input signal representative of a lighting setting (eg, bipolar or quadrupole illumination) can be received from the illumination system and processed in the control circuit to generate a control signal such that the trigger of the aperture mirror operator will The reflective surface of the pupil mirror is deformed to obtain a surface deformation having a double or quadruple rotational symmetry, such that at least a portion of the non-homogeneous lens heating that may be generated on the pole of the illumination may be asymmetrical. Mirror surface deformation compensation. Alternatively, or in addition, other input signals may also be generated or processed, for example, input signals representing pattern types (eg, line patterns, hole patterns, and/or patterns with lines in different directions), representative values The input signal of the aperture NA, and/or the input signal representing the number of exposures.
甚至更高之光學效能穩定性以及對干擾更佳之回應,可在包含封閉式迴路控制之投影物鏡效能之實施例中被取得。不像一簡單開放式迴路控制,封閉式迴路控制促成對控制電路之回饋。一些實施例中,控制電路包括至少一個回饋電路,此回饋電路包括至少一個第一感測器被設定來偵測光瞳鏡之反射表面的形狀,或是偵測相關於表面形狀之投影物鏡特性,其中,偵測器係連接於光瞳鏡控制單元以提供回饋訊號,以及,光瞳鏡控制單元被設定來選擇性地調整控制光瞳鏡操作器之控制訊號,以回應回饋訊號。舉例而言,波前量測裝置或者其他可量測投影物鏡之光學效能的量測系統可被用來產生訊號,例如,此訊號代表入射於像面及/或光瞳面之波前差的程度。波前差之程度特點在於有一或更多個差,包含一或多個單色像差,例如球面像差,慧差,像散,場曲以及失真,以及/或一或多個色差,其包含軸向或橫向色差,以及單色差之色變異。差超過一預定的臨界值後,光瞳鏡控制單元可能產生控制訊號以調整光瞳鏡的表面形狀,如此主要之差的程度可被減低於臨界值,其一般可見於使用者為某種製程提供之規格之中。如申請人之美國專利申請案US 2002/0011088 A1中偵測波前之裝置可與封閉式迴路控制一起被利用以將光瞳鏡之表面形狀最佳化。Even higher optical performance stability and better response to interference can be achieved in embodiments that include closed loop controlled projection objective performance. Unlike a simple open loop control, closed loop control facilitates feedback to the control circuitry. In some embodiments, the control circuit includes at least one feedback circuit including at least one first sensor configured to detect a shape of a reflective surface of the pupil mirror or to detect a projection objective characteristic associated with the surface shape The detector is connected to the optical mirror control unit to provide a feedback signal, and the optical mirror control unit is configured to selectively adjust the control signal for controlling the optical mirror operator to respond to the feedback signal. For example, a measurement system for the optical performance of a wavefront measurement device or other measurable projection objective can be used to generate a signal, for example, this signal represents the wavefront difference incident on the image plane and/or the pupil plane. degree. The degree of wavefront difference is characterized by one or more differences, including one or more monochromatic aberrations, such as spherical aberration, coma, astigmatism, curvature of field, and distortion, and/or one or more chromatic aberrations, Contains axial or lateral chromatic aberrations, as well as color variations in monochromatic differences. After the difference exceeds a predetermined threshold, the light mirror control unit may generate a control signal to adjust the surface shape of the aperture mirror, so that the degree of the main difference may be reduced below a critical value, which is generally visible to the user as a certain process. Among the specifications provided. The apparatus for detecting wavefronts in the applicant's US Patent Application No. US 2002/0011088 A1 can be utilized with closed loop control to optimize the surface shape of the pupil mirror.
光瞳鏡之表面形狀或者直接關連於表面形狀之投影物鏡之特徵可被長期或週期性地監視以取得回饋訊號。The surface shape of the pupil mirror or the features of the projection objective directly related to the surface shape can be monitored for a long time or periodically to obtain a feedback signal.
在開放式控制迴路或封閉式控制迴路中被處理之至少一輸入訊號可自一參數中取得,此參數係自對投影物鏡之量測中取得;換言之,此參數可在系統之直接被偵測。也可能自模擬模型中取得一或更多輸入訊號,其模擬模型可重製投影物鏡或一部分之投影物鏡,或者,重製具有足夠程度之精確度之投影曝光裝置,如此具有意義之控制參數以及訊號可被取得自模擬模型。此例中,光瞳鏡之控制可能包括模型為底(MBC)控制之各方面。為此目的,光瞳鏡控制單元可包含或可被連接於模型資料記憶體,儲存代表模擬模型之模型參數的模型資料,其中模擬模型係為投影物鏡或投影曝光裝置之模擬模型。控制系統可為控制電路取得至少一輸入訊號自模型資料記憶體中所儲存之模型資料。投影物鏡可包含一或多個第二感測器以偵測投影物鏡之實際狀態之參數,以取得實際可被觀察之參數,其係對應於模擬模型之模型參數。At least one input signal processed in the open control loop or the closed control loop can be obtained from a parameter obtained from the measurement of the projection objective; in other words, the parameter can be directly detected in the system. . It is also possible to obtain one or more input signals from the simulation model, the simulation model can reproduce the projection objective or a part of the projection objective, or reproduce a projection exposure device with a sufficient degree of precision, such meaningful control parameters and The signal can be taken from the simulation model. In this case, the control of the pupil mirror may include aspects of model-based (MBC) control. For this purpose, the pupil mirror control unit may include or be connected to the model data memory, and store model data representing model parameters of the simulation model, wherein the simulation model is a simulation model of the projection objective or the projection exposure device. The control system can obtain at least one input signal from the control circuit to store the model data stored in the model data memory. The projection objective may include one or more second sensors to detect parameters of the actual state of the projection objective to obtain actual observable parameters corresponding to the model parameters of the simulated model.
舉例而言,在圖11中所示之回饋控制系統,光瞳鏡控制單元PMCU包括模型資料記憶體MDM儲存代表投影物鏡1100以及/或投影曝光裝置之模擬模型之模型參數的模型資料。模型資料記憶體MDM可能包含於一外接裝置,可被光瞳鏡控制單元經由資料網路所存取。以上所述之實施例中,模型資料記憶體MDM可能已儲存一或更多的已下資料:溫度資料,代表一或更多元件之溫度;溫度分佈資料,代表一或更多元件之空間溫度分佈;位置資料,代表一或更多個元件的至少一軸向位置,一或更多元件之移位或傾斜;形狀資料,代表光瞳鏡之反射表面的形狀;孔徑資料,代表孔徑光闌的狀態(被使用之NA);設定資料,代表照明設定;輻射強度資料,代表輻射源之強度;差異資料,代表投影物鏡之光瞳鏡中或像場中的一或多個差異的空間分佈;浸沒資料,代表至少一浸沒介質之特徵,包含某一浸沒介質是否存在的指示資料;圖案資料,代表光罩或其他圖案裝置所提供之某類型圖案之資訊。模擬模型可於時間間隔被校正,利用對應至模型參數之已量測參數,而此等參數之資料被儲存以於模擬模型以及實際之操作系統之間維持一相近之關聯性。For example, in the feedback control system shown in FIG. 11, the pupil mirror control unit PMCU includes model data memory MDM storing model data representing model parameters of the projection objective 1100 and/or the simulation model of the projection exposure apparatus. The model data memory MDM may be included in an external device that can be accessed by the optical mirror control unit via the data network. In the above embodiments, the model data memory MDM may have stored one or more of the following data: temperature data, representing the temperature of one or more components; temperature distribution data, representing the spatial temperature of one or more components. Distribution; positional data representing at least one axial position of one or more elements, displacement or tilting of one or more elements; shape data representing the shape of the reflective surface of the pupil mirror; aperture data representing the aperture stop State (the NA being used); setting data, representing the illumination setting; radiation intensity data, representing the intensity of the radiation source; difference data, representative of the spatial distribution of one or more differences in the optical mirror of the projection objective or in the image field The immersion data represents at least one immersion medium characteristic, including indication information indicating whether or not an immersion medium exists; and the pattern data represents information of a certain type of pattern provided by the reticle or other pattern device. The simulation model can be corrected at time intervals using the measured parameters corresponding to the model parameters, and the data of these parameters are stored to maintain a close correlation between the simulation model and the actual operating system.
將控制適應性光瞳鏡之操作包含在模型為底之控制特徵中,可以是有利的,特別是考慮到適應性光瞳鏡可能會發生之某些問題,例如透鏡加熱效應,其係為隨著某些時間常數而產生之動態效應。進一步而言,光學系統之輻射能量分佈與對應之光學效能效應之間的關係是很不簡單的。若封閉式迴路控制電路被使用,則,投影物鏡實際上之光學效能,於特定之時間間隔,被拿來與事先理論的或所欲達成之數值做比較,其通常為使用者之規格。若於實際數值以及所欲達成之數值之間有差異,控制電路可藉由適當之操作,有效地減少這些差異,操作可包含如在光瞳鏡上之操作。一般而言,此種封閉式迴路控制係可反應所觀察到之錯誤,以及有效地移除或最小化這些錯誤。一般而言,將模型為底之控制之各方面整合,可用來達成光學系統被估測之控制,如此,當模擬模型被設計時,可使至少某些未來可能發生之改變被納入考慮。一前瞻動作之控制可被達成。It may be advantageous to include the operation of controlling the adaptive pupilscope in the model-based control feature, particularly in view of certain problems that may occur with an adaptive pupiltoscope, such as a lens heating effect, which is The dynamic effects produced by certain time constants. Further, the relationship between the radiant energy distribution of the optical system and the corresponding optical efficiency effect is not simple. If a closed loop control circuit is used, the actual optical performance of the projection objective is compared to a theoretical or desired value at a particular time interval, which is typically the user's specification. If there is a difference between the actual value and the desired value, the control circuit can effectively reduce these differences by appropriate operation, which can include operations such as on a pupil. In general, such closed loop control systems can reflect observed errors and effectively remove or minimize these errors. In general, the integration of all aspects of the model-based control can be used to achieve the control of the optical system being estimated, so that when the simulation model is designed, at least some of the future changes that may occur are taken into account. The control of a forward-looking action can be achieved.
如美國專利申請案US 2006/0114437 A1所揭露之微影投影裝置包含量測系統,量測系統係用來量測投影系統中隨時間改變之差異,以及,包含估測控制系統,基於模型參數,可用來估測投影系統隨時間改變之差異。就此而言,此處之觀念可能被修改以可被用於控制適應性光瞳鏡,此份文件之揭露內容被併入本申請案作為參考。A lithographic projection apparatus as disclosed in US Patent Application No. US 2006/0114437 A1 includes a measurement system for measuring a change in time in a projection system, and an estimation control system based on model parameters Can be used to estimate the difference in projection system over time. In this regard, the concepts herein may be modified to be used to control an adaptive aperture mirror, the disclosure of which is hereby incorporated by reference.
模擬模型之持續或間歇校正可被達成,其係基於對被模型化之系統特性之實際量測所取得之訊號。在實體系統(例如投影物鏡或整個曝光裝置)上被偵測或被決定之特性可包含一或更多以下資訊:一或更多元件之溫度,一或更多元件之空間溫度分佈,一或更多個元件的軸向位置,一或更多元件之移位或傾斜,光瞳鏡之反射表面的形狀,孔徑光闌的狀態(被使用之NA),照明設定,輻射源之強度,投影物鏡之光瞳鏡出口中或像場中的一或多個差異的空間分佈,光瞳表面之波前,例如瞳出口,光瞳表面之強度的空間分佈或強度分佈,光罩或其他圖案裝置所提供之某類型圖案。舉例而言,圖案資訊可被取得自讀取光罩之相關圖案識別資料,以及/或,儲存於與每一光罩有關之可交換之記憶體元件的資料,以及/或,儲存於永久性記憶體元件之資料。Continuous or intermittent correction of the simulation model can be achieved based on the actual measurement of the characteristics of the modeled system. A feature that is detected or determined on a physical system (eg, a projection objective or an entire exposure device) may include one or more of the following information: temperature of one or more components, spatial temperature distribution of one or more components, or The axial position of more components, the displacement or tilt of one or more components, the shape of the reflective surface of the pupil mirror, the state of the aperture stop (the NA being used), the illumination setting, the intensity of the radiation source, the projection The spatial distribution of one or more differences in the exit or image field of the objective lens, the wavefront of the pupil surface, such as the exit of the pupil, the spatial distribution or intensity distribution of the intensity of the pupil surface, the reticle or other patterning device A type of pattern provided. For example, the pattern information can be obtained from the associated pattern recognition material of the reticle and/or stored in the memory component associated with each reticle, and/or stored in permanent Information on memory components.
控制系統中用來控制可形變面鏡之各種不同設定,可被用於本發明所揭露之實施例中,或於其他投影曝光系統,例如,獨立於折疊幾何以及中間影像之數目。舉例而言,具有多於兩個中間影像之投影物鏡是可能的。具有三個中間影像之投影物鏡實質上可依照申請人之國際申請案WO 2005/040890被設計,其揭露內容被併入本申請案作為參考。The various settings used in the control system to control the deformable mirror can be used in embodiments of the present disclosure, or in other projection exposure systems, for example, independent of the folding geometry and the number of intermediate images. For example, a projection objective with more than two intermediate images is possible. A projection objective having three intermediate images is substantially designed in accordance with the applicant's international application WO 2005/040890, the disclosure of which is hereby incorporated by reference.
以上所述之較佳實施例係以舉例之方式敘述。藉由此等揭露內容,熟知此項技藝之人士不僅可了解本發明以及其優點,也應了解所揭露之架構或方法可能有各種不同之改變或調整。因此,本說明書之申請專利範圍,以及其均等,包含落於本發明之範疇與精神之所有可能之改變或調整。The above described preferred embodiments are described by way of example. The disclosure of the present invention, as well as its advantages, may be understood by those skilled in the art, and it should be understood that various modifications and changes may be made in the structure or method disclosed. Accordingly, the scope of the invention, as well as its equivalents, are intended to cover all such modifications and variations of the scope and spirit of the invention.
100...反射折射投影物鏡100. . . Reflection refraction projection objective
500...線內投影物鏡500. . . Inline projection objective
600、1000...投影物鏡600, 1000. . . Projection objective
AS...孔徑光闌AS. . . Aperture stop
CR...主要光束CR. . . Main beam
CRA...主要光束角度CRA. . . Main beam angle
CRAPM ...光瞳鏡PM之主要光束角度CRA PM . . . Main beam angle of the light mirror PM
CRHO ...物面主要光束高度CRH O . . . Main beam height of the object surface
CRHM ...面鏡上之主要光束高度CRH M . . . Main beam height on the mirror
CON...壓縮部CON. . . Compression department
D0 ...光瞳鏡表面之一邊緣光束高度數量值的兩倍D 0 . . . Twice the number of edge beam heights on one of the pupil mirror surfaces
Di...場點i於光瞳入口之影像子午線方向之一直徑Di. . . The field point i is one of the diameters of the image meridian direction at the entrance of the pupil
DPM ...光學直徑D PM . . . Optical diameter
ES...光出口表面ES. . . Light exit surface
FP...彈性部分FP. . . Elastic part
FPO...光軸上之場點FPO. . . Field point on the optical axis
IMI1...第一中間影像IMI1. . . First intermediate image
IMI2...第二中間影像IMI2. . . Second intermediate image
IF...像場IF. . . Image field
IS...物面IS. . . Object
IM...浸沒介質IM. . . Immersion medium
ILL...照明系統ILL. . . Lighting system
IR...離軸照明區域IR. . . Off-axis illumination area
LG1...第一透鏡組LG1. . . First lens group
LG2...第二透鏡組LG2. . . Second lens group
LG3...第三透鏡組LG3. . . Third lens group
LG4...第四透鏡組LG4. . . Fourth lens group
MGI...鏡組入口MGI. . . Mirror group entrance
MGO...鏡組出口MGO. . . Mirror outlet
MG...鏡組MG. . . Mirror group
M1...第一鏡片M1. . . First lens
M2...第二鏡片M2. . . Second lens
M3...第三鏡片M3. . . Third lens
M4...第四鏡片M4. . . Fourth lens
MGP...鏡組平面MGP. . . Mirror plane
MR...邊緣光線MR. . . Edge light
OA...光軸OA. . . Optical axis
OF...物場OF. . . Object field
OS...物面OS. . . Object
OP1...第一物鏡部件OP1. . . First objective lens component
OP2...第二物鏡部件OP2. . . Second objective lens component
OP3...第三物鏡部件OP3. . . Third objective lens component
P1...第一光瞳面P1. . . First pupil face
P2...第二光瞳面P2. . . Second pupil face
P3...第三光瞳面P3. . . Third pupil face
PCL...平凸透鏡PCL. . . Plano-convex lens
PO...投影物鏡PO. . . Projection objective
PS...光瞳表面PS. . . Optical surface
PM...光瞳鏡PM. . . Light mirror
PMM...光瞳鏡操作器PMM. . . Light mirror operator
PMCU...光瞳鏡控制單元PMCU. . . Mirror control unit
RA1...反射區域RA1. . . Reflective area
RA3...反射區域RA3. . . Reflective area
RP...堅硬部分RP. . . Hard part
RRL...下緣光束RRL. . . Lower edge beam
RRU...上緣光束RRU. . . Upper edge beam
RD...容納裝置RD. . . Containing device
RS...光柵台RS. . . Grating table
SENS1...第一感測器SENS1. . . First sensor
SENS2...第二感測器SENS2. . . Second sensor
SS...基板表面SS. . . Substrate surface
W...裝置W. . . Device
WS...晶圓台WS. . . Wafer table
圖1所示為第一實施例中用做微影蝕刻之線內反射折射乾式物鏡之透鏡部份,其具有可形變之凹光瞳鏡,於NA=0.93;圖2所示為線內反射折射投影物鏡之軸向部份之示意圖,其類似於圖1之實施例;圖3所示為圖1之實施例中的鏡組的區域的細部放大,於共同基板上,其包括形成適應性光瞳鏡以及離軸照明面鏡之凹鏡組;圖4所示為影響於光瞳鏡之投影光束之校正狀態之示意圖;圖5所示為第二實施例中用做浸沒微影之線內反射折射投影物鏡之透鏡部份,其利用一矩形之有效物場,於NA=1.2;圖6所示為第三實施例中用做浸沒微影之線內反射折射投影物鏡之透鏡部份,利用一拱形之有效物場,於NA=1.55;圖7、圖8所示為線內反射折射投影物鏡之軸向部份之示意圖,其具有四個面鏡之鏡組,其中包括一或兩個(圖8)光瞳鏡;圖9所示為用做微影蝕刻之掃描投影曝光系統,其具有被設計來產生裂縫形狀之照明場之照明系統,以及具有四個凹面鏡且其一包含可形變光瞳鏡之反射折射投影物鏡;圖10所示為線內反射折射投影物鏡之透鏡部份,此投影物鏡適用於乾式微影,利用拱形有效物場,於NA=0.75;以及圖11所示為折疊式反射折射投影物鏡之透鏡部分之實施例,其適用於浸沒微影,利用矩形之有效物場,於NA=1.25。1 is a lens portion of an in-line reflective refraction dry objective lens used for lithography etching in the first embodiment, which has a deformable concave aperture mirror at NA=0.93; FIG. 2 shows an in-line reflection. A schematic view of an axial portion of a refraction projection objective, similar to the embodiment of FIG. 1; FIG. 3 is an enlarged detail of a region of the mirror assembly of the embodiment of FIG. 1, on a common substrate, including adaptation The light mirror and the concave mirror group of the off-axis illumination mirror; FIG. 4 is a schematic diagram showing the correction state of the projection beam affecting the pupil mirror; FIG. 5 is the line used for immersion lithography in the second embodiment. The lens portion of the internal reflection refraction projection objective uses a rectangular effective object field at NA = 1.2; Figure 6 shows the lens portion of the in-line reflection refraction projection objective used as the immersion lithography in the third embodiment. Using an arched effective object field at NA=1.55; FIG. 7 and FIG. 8 are schematic diagrams showing the axial portion of the in-line reflective refraction projection objective lens, which has a mirror set of four mirrors, including one Or two (Fig. 8) pupil mirrors; Figure 9 shows a scanning projection system for lithography etching An illumination system having an illumination field designed to produce a crack shape, and a catadioptric projection objective having four concave mirrors and one comprising a deformable aperture mirror; FIG. 10 is a lens of an in-line reflection refraction projection objective In part, the projection objective is suitable for dry lithography, using an arched effective object field at NA=0.75; and FIG. 11 is an embodiment of a lens portion of a folded reflective refractive index objective lens, which is suitable for immersion lithography. Use the effective object field of the rectangle at NA = 1.25.
100...反射折射投影物鏡100. . . Reflection refraction projection objective
MG...鏡組MG. . . Mirror group
CR...主要光束CR. . . Main beam
M1...第一鏡片M1. . . First lens
CON...壓縮部CON. . . Compression department
M2...第二鏡片M2. . . Second lens
IMI1...第一中間影像IMI1. . . First intermediate image
M3...第三鏡片M3. . . Third lens
IMI2...第二中間影像IMI2. . . Second intermediate image
M4...第四鏡片M4. . . Fourth lens
IF...像場IF. . . Image field
MGP...鏡組平面MGP. . . Mirror plane
IS...物面IS. . . Object
OA...光軸OA. . . Optical axis
LG1...第一透鏡組LG1. . . First lens group
OF...物場OF. . . Object field
LG2...第二透鏡組LG2. . . Second lens group
OS...物面OS. . . Object
LG3...第三透鏡組LG3. . . Third lens group
P1...第一光瞳面P1. . . First pupil face
LG4...第四透鏡組LG4. . . Fourth lens group
P2...第二光瞳面P2. . . Second pupil face
MGI...鏡組入口MGI. . . Mirror group entrance
P3...第三光瞳面P3. . . Third pupil face
MGO...鏡組出口MGO. . . Mirror outlet
PM...光瞳鏡PM. . . Light mirror
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TW107116998A TW201908871A (en) | 2006-08-14 | 2007-08-13 | Catadioptric projection objective with pupil mirror, projection exposure apparatus and projection exposure method |
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Families Citing this family (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103135356B (en) * | 2011-11-23 | 2015-04-15 | 上海微电子装备有限公司 | Reflection-type photoetching projection objective |
CN102436058B (en) * | 2011-12-14 | 2013-08-21 | 北京理工大学 | Full spherical catadioptric collimating objective lens applied to deep ultraviolet band |
JP6028350B2 (en) * | 2012-03-16 | 2016-11-16 | 株式会社ニコン | Substrate processing apparatus, device manufacturing system, and device manufacturing method |
DE102013204391B3 (en) * | 2013-03-13 | 2014-05-28 | Carl Zeiss Smt Gmbh | Projection lens for imaging projection lens pattern from object plane into image plane, has field point in field plane of outgoing beam illuminating manipulator surface with sub-aperture, and manipulation system comprising manipulator |
US9651872B2 (en) | 2013-03-13 | 2017-05-16 | Carl Zeiss Smt Gmbh | Projection lens with wavefront manipulator |
CN103353669B (en) * | 2013-07-30 | 2015-07-15 | 中国科学院光电技术研究所 | High numerical aperture immersion projection objective |
TW201514541A (en) * | 2013-09-19 | 2015-04-16 | 尼康股份有限公司 | Projection optical system, adjusting method thereof, exposing device and method, and device manufacturing method |
CN105116527B (en) * | 2015-09-25 | 2018-10-30 | 上海新跃仪表厂 | A kind of infrared refractive and reflective optical system of low distortion wide-angle length of object lens of large relative aperture |
JP6748482B2 (en) * | 2016-05-25 | 2020-09-02 | キヤノン株式会社 | Exposure apparatus and method for manufacturing article |
CN108152940B (en) * | 2016-12-05 | 2021-04-27 | 佳能株式会社 | Catadioptric optical system, illumination optical system, and exposure apparatus |
CN109581622B (en) | 2017-09-29 | 2020-12-04 | 上海微电子装备(集团)股份有限公司 | Projection objective |
JP2019124796A (en) * | 2018-01-16 | 2019-07-25 | キヤノン株式会社 | Imaging optical system, image projection device, and camera system |
US11067389B2 (en) * | 2018-03-13 | 2021-07-20 | Kla Corporation | Overlay metrology system and method |
CN109298517B (en) * | 2018-11-05 | 2020-10-30 | 中国航空工业集团公司洛阳电光设备研究所 | Multispectral coaxial catadioptric afocal optical system |
US20220334499A1 (en) * | 2019-09-10 | 2022-10-20 | Asml Netherlands B.V. | Sub-field control of a lithographic process and associated apparatus |
KR102409108B1 (en) * | 2020-09-18 | 2022-06-15 | 삼성전기주식회사 | Optical Imaging System |
CN113687500B (en) * | 2021-08-03 | 2024-03-26 | 润坤(上海)光学科技有限公司 | Optical system of deflection type detector |
DE102021213827A1 (en) * | 2021-12-06 | 2023-06-07 | Carl Zeiss Smt Gmbh | Method for optimizing a pupil diaphragm shape for simulating lighting and imaging properties of an optical production system when illuminating and imaging an object using an optical measuring system |
TWI813395B (en) * | 2022-07-22 | 2023-08-21 | 新鉅科技股份有限公司 | Optical lens assembly and head-mounted electronic device |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01120855U (en) * | 1988-02-08 | 1989-08-16 | ||
JPH0215131U (en) * | 1988-07-13 | 1990-01-30 | ||
JP3368091B2 (en) * | 1994-04-22 | 2003-01-20 | キヤノン株式会社 | Projection exposure apparatus and device manufacturing method |
JP3781044B2 (en) * | 1994-11-07 | 2006-05-31 | 株式会社ニコン | Catadioptric optical system and projection exposure apparatus |
JPH10301058A (en) * | 1997-04-30 | 1998-11-13 | Nikon Corp | Reflection refraction type projecting optical system |
DE19824030A1 (en) * | 1998-05-29 | 1999-12-02 | Zeiss Carl Fa | Catadioptric projection lens with adaptive mirror and projection exposure method |
DE10120446C2 (en) * | 2001-04-26 | 2003-04-17 | Zeiss Carl | Projection exposure system and method for compensating imaging errors in a projection exposure system, in particular for micro-lithography |
JP2005037896A (en) * | 2003-05-23 | 2005-02-10 | Canon Inc | Projection optical system, exposure apparatus and device manufacturing method |
JP2005019628A (en) * | 2003-06-25 | 2005-01-20 | Nikon Corp | Optical apparatus, aligner, manufacturing method of device |
CN102169226B (en) * | 2004-01-14 | 2014-04-23 | 卡尔蔡司Smt有限责任公司 | Catadioptric projection objective |
JP2005311020A (en) * | 2004-04-21 | 2005-11-04 | Nikon Corp | Exposure method and method of manufacturing device |
KR20140138350A (en) * | 2004-05-17 | 2014-12-03 | 칼 짜이스 에스엠티 게엠베하 | Catadioptric projection objective with intermediate images |
JP4843272B2 (en) * | 2004-07-31 | 2011-12-21 | カール・ツァイス・エスエムティー・ゲーエムベーハー | Optical system for microlithographic projection exposure apparatus |
JP4581662B2 (en) * | 2004-12-07 | 2010-11-17 | 株式会社ニコン | Projection optical system, exposure apparatus, and device manufacturing method |
JP2009122247A (en) * | 2007-11-13 | 2009-06-04 | Kayaba Ind Co Ltd | Article in contact with human body during use |
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JP2014123749A (en) | 2014-07-03 |
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CN101523294A (en) | 2009-09-02 |
TWI529502B (en) | 2016-04-11 |
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JP2016157137A (en) | 2016-09-01 |
TWI531874B (en) | 2016-05-01 |
JP2010500769A (en) | 2010-01-07 |
TW201908871A (en) | 2019-03-01 |
JP5462739B2 (en) | 2014-04-02 |
JP2014074930A (en) | 2014-04-24 |
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