JP5216738B2 - Optical element, lithographic apparatus, and method for manufacturing an optical element - Google Patents

Description

The present invention relates generally to lithography, and more specifically to antireflective coatings for optical elements.

Lithography is widely recognized as an important process in the manufacture of integrated circuits (ICs) and other devices and / or structures. A lithographic apparatus is a machine used during lithography that applies a desired pattern onto a substrate, such as on a target portion of the substrate. During the manufacture of an IC by a lithographic apparatus, a patterning device (or called a mask or a reticle) generates a circuit pattern that is formed on an individual layer in the IC. This pattern can be transferred onto a target portion (eg including part of, one, or several dies) on a substrate (eg a silicon wafer). The pattern is usually transferred by forming an image on a layer of radiation-sensitive material (for example, resist) provided on the substrate. In general, a single substrate will contain a plurality of target portions that are successively patterned. In many cases, manufacturing different layers of an IC requires imaging different patterns on different layers using different reticles. Therefore, the reticle must be changed during the lithography process.

A lithographic apparatus and the patterning device included therein often include one or more mirrors for reflecting and redirecting the radiation beam. For example, such devices often include a micro-electromechanical system (MEMS) that includes an array of individual mirrors. A mirror in such a system deposits a highly reflective coating (eg, a layer of aluminum, aluminum oxide, silicon oxide, and various metal fluorides) on a portion of the surface of the silicon substrate and is incident in a particular way. It is formed by reflecting.

However, uncoated silicon can reflect up to 60% of incident radiation at deep ultraviolet (DUV) wavelengths (compared to fused silica or calcium fluoride (CaF ₂ ) substrates). Reflection is less than 5% over range). Thus, the light reflected from the portion of the substrate that is not intentionally coated with the highly reflective coating can be equivalent in intensity to the light reflected from the portion coated with the highly reflective coating. Thus, an uncoated silicon substrate may scatter reflected light, which may interfere with radiation reflected by the portion coated with the highly reflective coating.

Accordingly, antireflection coatings are often applied to these exposed portions of the surface of the silicon substrate to substantially reduce or eliminate unwanted reflections and scattering of incident radiation. However, unlike existing mirror systems used in lithographic apparatus incorporating fused silica or calcium fluoride substrates, efficient single layer anti-reflective coatings are generally optical devices such as MEMS incorporating silicon substrates. Is impossible. What is needed is a method and system for overcoming the above-mentioned drawbacks.

In view of the foregoing, there is a need for a single layer anti-reflective coating for silicon substrates that substantially reduces or eliminates the reflection of radiation incident on the substrate (eg, 193 nm DUV radiation). To meet this need, embodiments of the present invention are directed to a single layer anti-reflective coating for a silicon substrate.

In one embodiment, the optical element includes a silicon substrate and a reflective layer disposed on the first portion of the surface of the silicon substrate. An antireflective layer is disposed on the second portion of the surface of the silicon substrate to substantially reduce reflection of radiation incident on the antireflective layer by destructive interference in the antireflective layer.

In yet another embodiment, a support structure configured to support a patterning device configured to pattern a radiation beam from an illumination system and an optical element support configured to support an optical element. And a projection system configured to project a patterned beam. The optical element includes a silicon substrate and a reflective layer disposed on the first portion of the surface of the silicon substrate. An antireflective layer is disposed on the second portion of the surface of the silicon substrate, and the antireflective layer substantially reduces the reflection of radiation incident on the antireflective layer by destructive interference.

  In yet another embodiment, a method for manufacturing an optical element includes disposing an antireflective layer on a first portion of a surface of a silicon substrate and disposing an antireflective layer on a second portion of the surface of the silicon substrate. . The second placement step includes determining the composition of the oxide layer and the thickness of the oxide layer to generate destructive interference that substantially reduces the reflection of radiation incident on the antireflective layer. In one implementation, the wavelength of the incident radiation is 193 nm.

Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the specific embodiments described herein. Such embodiments are presented herein for illustrative purposes only. Other embodiments will be apparent to those skilled in the art based on the teachings contained herein.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the invention and, together with the description, explain the principles of the invention and enable those skilled in the art to make and use the invention. To help.

1 shows a reflective lithographic apparatus. 1 shows a transmissive lithographic apparatus; FIG. 2 schematically illustrates features of an exemplary optical element having a single layer anti-reflective coating, according to an embodiment of the invention. FIG. FIG. 6 schematically illustrates features of an exemplary optical element having a single layer anti-reflective coating, according to yet another embodiment of the present invention. Figure 3 shows the reflective features of the exemplary optical element of Figure 2; Figure 3 shows the reflective features of the exemplary optical element of Figure 2; 6 is a graph showing the percentage of reflection of an antireflective coating of a specific composition and thickness for incident light in a wavelength range. 2 illustrates an exemplary method for producing an optical element having a single layer anti-reflective coating, according to one embodiment of the invention.

The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings. Throughout the drawings, like numerals identify corresponding elements. In the drawings, like reference numbers typically indicate identical, functionally similar, and / or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit (s) in the corresponding reference number.

I. Overview
The present invention is directed to a single layer anti-reflective coating for a silicon substrate. This patent document describes one or more embodiments that incorporate the features of this invention. These embodiments are merely illustrative of the invention. The scope of the invention is not limited to the disclosed embodiments. The invention is defined by the claims.

The described embodiment and references herein such as “one embodiment,” “embodiment,” “exemplary embodiment,” and the like refer to a particular feature, structure, or feature that the described embodiment describes. It can be included, but indicates that all embodiments may not necessarily include that particular feature, structure, or feature. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or feature is described in connection with an embodiment, such feature, structure, or feature may be expressed in other implementations, whether explicitly described or not. It will be understood that implementation in conjunction with the form is within the knowledge of one of ordinary skill in the art.

Before describing such embodiments in further detail, it is beneficial to present exemplary embodiments in which embodiments of the present invention can be implemented.

II. Exemplary reflective and transmissive lithography system
1A and 1B schematically depict lithographic apparatus 100 and lithographic apparatus 100 ′, respectively. The lithographic apparatus 100 and the lithographic apparatus 100 ′ each include an illumination system (illuminator) IL configured to condition a radiation beam B (eg, DUV or EUV radiation) and a patterning device (eg, mask, reticle, or dynamic patterning). A support structure (eg mask table) MT configured to support the device MA and connected to the first positioner PM configured to accurately position the patterning device MA; and a substrate (eg resist coated). And a substrate table (eg, wafer table) WT connected to a second positioner PW configured to hold the substrate W and configured to accurately position the substrate W. The lithographic apparatuses 100 and 100 ′ may also be configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (eg, including one or more dies) C of the substrate W. It also has a system PS. In the lithographic apparatus 100, the patterning device MA and the projection system PS are reflective, and in the lithographic apparatus 100 ′, the patterning device MA and the projection system PS are transmissive.

The illumination system IL can be used in various ways, such as refraction, reflection, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof to direct, shape, or control the radiation B Types of optical components may be included.

The support structure MT is patterned in a manner that depends on the orientation of the patterning device MA, the design of the lithographic apparatuses 100 and 100 ′, and other conditions, such as for example whether or not the patterning device MA is held in a vacuum environment. Hold. The support structure MT can hold the patterning device MA using mechanical, vacuum, electrostatic or other clamping techniques. The support structure MT can be, for example, a frame or table that can be fixed or movable as required. The support structure MT may ensure that the patterning device is at a desired position, for example with respect to the projection system PS.

The term “patterning device” MA should be broadly interpreted to refer to any device that can be used to pattern the cross section of the radiation beam B, such as to create a pattern in a target portion C of a substrate W. It is. The pattern imparted to the radiation beam B can correspond to a particular functional layer in the device being created in the target portion C, such as an integrated circuit.

Patterning device MA may be transmissive (as in lithographic apparatus 100 ′ of FIG. 1B) or reflective (as in lithographic apparatus 100 of FIG. 1A). Examples of patterning device MA include reticles, masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include mask types such as binary, alternating phase shift, and attenuated phase shift, as well as various hybrid mask types. One example of a programmable mirror array uses a matrix array of small mirrors, each of which can be individually tilted to reflect the incoming radiation beam in a different direction. The tilted mirror provides a pattern of radiation beam B that is reflected to the mirror matrix.

The term “projection system” PS refers to refraction, reflection, catadioptric, magnetic, electromagnetic, and electrostatic optics appropriate to the exposure radiation used or other factors such as the use of immersion liquid or vacuum. Any type of projection system including a system, or any combination thereof, can be included. For EUV or electron beam radiation, a vacuum environment can be used. This is because other gases may absorb too much radiation or electrons. Therefore, a vacuum environment can be provided to the entire beam path using a vacuum wall and a vacuum pump.

The lithographic apparatus 100 and / or lithographic apparatus 100 ′ may be of a type having two (dual stage) or more substrate tables (and / or two or more mask tables) WT. In such a “multi-stage” machine, additional substrate tables WT can be used simultaneously, or one or more other substrate tables WT are used for exposure while performing preparatory steps on one or more tables. Is also possible.

1A and 1B, the illuminator IL receives a radiation beam from a radiation source SO. For example, if the source SO is an excimer laser, the source SO and the lithographic apparatus 100, 100 ′ may be separate entities. In such a case, the radiation source SO is not considered to form part of the lithographic apparatus 100, 100 ′, for example using a beam delivery system BD (FIG. 1B) including a suitable directing mirror and / or beam expander. Beam B travels from radiation source SO to illuminator IL. In other cases the source SO may be an integral part of the lithographic apparatuses 100, 100 ′, for example when the source SO is a mercury lamp. The radiation source SO and the illuminator IL, together with the beam delivery system BD, may be referred to as a radiation system if necessary.

The illuminator IL may include an adjuster AD (FIG. 1B) for adjusting the angular intensity distribution of the radiation beam. In general, at least the outer and / or inner radial extent (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution can be adjusted in the pupil plane of the illuminator. Further, the illuminator IL may include various other components (FIG. 1B) such as an integrator IN and a capacitor CO. The illuminator IL can be used to adjust the radiation beam B to have the desired uniformity and intensity distribution in its cross section.

Referring to FIG. 1A, the radiation beam B is incident on the patterning device (eg, mask) MA, which is held on the support structure (eg, mask table) MT, and is patterned by the patterning device MA. In the lithographic apparatus 100, the radiation beam B is reflected from the patterning device (eg mask) MA. After being reflected from the patterning device (eg mask), the radiation beam B passes through the projection system PS, which focuses the radiation beam B onto the target portion C of the substrate W. The second positioner PW and position sensor IF2 (eg interferometer device, linear encoder or capacitive sensor) are used to accurately position the substrate table WT to position different target portions C in the path of the radiation beam B, for example. Can be moved. Similarly, the patterning device (eg mask) MA can be accurately positioned with respect to the path of the radiation beam B using the first positioner PM and another position sensor IF1. Patterning device (eg mask) MA and substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2.

Referring to FIG. 1B, the radiation beam B is incident on the patterning device (eg, mask MA) having the mask pattern MP, which is held on the support structure (eg, mask table MT), and is patterned by the patterning device. After traversing the mask MA, the radiation beam B passes through the projection system PS, which focuses the beam onto the target portion C of the substrate W. The projection system PS includes a pupil PPU and an aperture device PD. The PD can be, for example, a programmable LCD array. The second positioner PW and position sensor IF (eg interferometer device, linear encoder or capacitive sensor) are used to accurately position the substrate table WT so as to position different target portions C in the path of the radiation beam B, for example. Can be moved to. Similarly, the path of the radiation beam B using a first positioner PM and another position sensor (which is not explicitly shown in FIG. 1B), for example after mechanical retrieval from a mask library or during a scan. Therefore, the mask MA can be accurately positioned.

In general, the movement of the mask table MT can be realized by using a long stroke module (coarse positioning) and a short stroke module (fine positioning) that form a part of the first positioner PM. Similarly, the movement of the substrate table WT can be realized using a long stroke module and a short stroke module that form part of the second positioner PW. In the case of a stepper (relative to the scanner), the mask table MT can be connected only to a short stroke actuator or fixed. Mask MA and substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. The substrate alignment marks occupy dedicated target portions as shown, but they can also be placed in the space between target positions (known as scribe line alignment marks). Similarly, in situations where more than one die is provided on the mask MA, mask alignment marks can be placed between the dies.

The illustrated lithographic apparatuses 100 and 100 ′ can be used in at least one of the following modes:
1. In step mode, the support structure MT and the substrate table WT are basically kept stationary, while the entire pattern imparted to the radiation beam is projected onto the target portion C at one time (ie one static exposure). ). Next, the substrate table WT is moved in the X and / or Y direction so that another target portion C can be exposed.
2. In scan mode, the support structure MT and the substrate table WT are scanned synchronously while a pattern imparted to the radiation beam is projected onto a target portion C (ie, one dynamic exposure). The speed and direction of the substrate table WT relative to the support structure MT can be determined by the enlargement (reduction) and image reversal characteristics of the projection system PS.
3. In another mode, the support structure MT is held essentially stationary while holding the programmable patterning device, and projects the pattern imparted to the radiation beam onto the target portion C while moving or scanning the substrate table WT. In this mode, a pulsed radiation source is typically used to update the programmable patterning device as needed each time the substrate table WT is moved or between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of a type as referred to above.

Combinations and / or variations on the above described modes of use or entirely different modes of use may also be employed.

Although particular reference is made herein to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein has other uses. For example, this is the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, and the like. In light of these alternative applications, the use of the terms “wafer” or “die” herein are considered synonymous with the more general terms “substrate” or “target portion”, respectively. Those skilled in the art will recognize that this may be the case. The substrates described herein may be processed before or after exposure, for example, with a track (usually a tool that applies a layer of resist to the substrate and develops the exposed resist), metrology tools, and / or inspection tools. be able to. Where appropriate, the disclosure herein may be applied to these and other substrate processing tools. In addition, the substrate can be processed multiple times, for example to produce a multi-layer IC, so the term substrate as used herein can also refer to a substrate that already contains multiple processed layers.

III. Exemplary single layer anti-reflective coating for silicon substrates
In order to form an efficient single layer anti-reflective coating on any material, the refractive index of the coating material must be approximately equal to the square root of the substrate material. Conventional antireflective compounds such as metal fluoride, silicon dioxide, aluminum oxide do not satisfy this optical constraint over a range of wavelengths within the DUV emission range, such as 193 nm. For this reason, conventional anti-reflective coatings for silicon substrates generally incorporate two or more separate layers of conventional coating materials such as metal fluoride, silicon dioxide, aluminum oxide, silicon nitride, and silicon oxynitride. The embodiments presented herein provide a single layer anti-reflective coating of the thickness and composition necessary to substantially eliminate radiation incident on the anti-reflective layer.

FIG. 2A illustrates an exemplary optical element 200 according to one embodiment of the present invention. The optical element 200 includes a silicon substrate 202, a reflective coating 206, and an antireflective coating 208. A reflective coating 206 and an antireflective coating 208 are deposited on the surface 202 a of the silicon substrate 202. In one embodiment, the optical element 200 is a MEMS device and the mirror surface formed by the reflective coating 206 substantially reflects all light incident thereon. The reflective coating 206 can be formed by depositing a reflective material such as aluminum, aluminum oxide, silicon oxide, or metal fluoride. Those skilled in the art will recognize that the type of material used to form the reflective coating 206 can be arbitrary based on design requirements.

According to one embodiment of the present invention, a single layer of reflection having a specific composition and thickness to prevent light reflected / scattered from the surface 202a of the silicon substrate 202 from interfering with light reflected from the reflective coating 206. A preventive coating 208 is applied over the portion of the surface 202 a of the silicon substrate 202 that is not covered by the reflective coating 206. In many cases, the antireflective coating is applied to all portions of the surface 202a that the reflective coating 206 does not cover. In other cases, the antireflective coating is not applied to all portions of the surface 202a that the reflective coating 206 does not cover. In accordance with one embodiment of the present invention, the refractive index of the antireflective coating 208 is that of the refractive index of the underlying silicon substrate 202 to substantially minimize the reflection of light incident on the antireflective coating 208. Must be approximately equal to the square root. For this reason, if the refractive index of the silicon substrate is n, the refractive index of the antireflection coating must be approximately equal to √n. At this refractive index, the light reflected from the antireflective coating 208 interferes with the light reflected from the underlying surface 202a in a destructive manner, thereby substantially reflecting the light incident on the antireflective coating 208. Exclude. The composition and thickness of the anti-reflective coating 208 to minimize reflection is based in part on the wavelength of incident radiation.

According to one embodiment of the present invention, a 10 nm single layer of hafnium oxide antireflective coating 208 is deposited on the surface 202a of the silicon substrate 202 to minimize reflection of light having a wavelength of 193 nm. A single layer of hafnium oxide of desired thickness and composition can be deposited using, for example, ion assisted electron beam (E-beam) deposition. Ion-assisted electron beam deposition includes injecting a controlled amount of oxygen into the deposition chamber while evaporating hafnium using the electron beam in the deposition chamber. In order to control the composition of hafnium oxide, ion assistance is used along with the level of oxygen input into the deposition chamber. By controlling the oxygen content, the refractive index of hafnium oxide can be adjusted to √n. Here, n is the refractive index of the silicon substrate 202. The reflective coating 206 can be deposited on the silicon substrate 202 using techniques such as sputtering, chemical vapor deposition (CVD), or physical vapor deposition (PVD). The composition and thickness of the antireflective coating 208 is configured to produce a single layer coating that satisfies the optical constraints of the refractive index of the antireflective coating 208 to be the square root of the refractive index of the silicon substrate 202. Yes. In one embodiment, the thickness and composition of the antireflective coating 208 causes destructive interference between the light reflected from the antireflective coating 208 and the light reflected from the underlying substrate 202, and this cancellation. The reflection of light incident on the antireflective coating 208 as a result of general interference is configured to be substantially negligible. In alternative embodiments, other thicknesses of other hafnium oxides, tantalum oxides, niobium, titanium oxides, and silicon nitrides can be used to form the anti-reflective coating 208.

FIG. 2B shows an exemplary optical element 220 according to one embodiment of the present invention. The optical element 220 includes a silicon substrate 202, a reflective coating 206, and an antireflective coating 208. In this embodiment, the antireflective coating 208 is deposited on the entire surface 202 a of the substrate 202. A reflective coating 206 is deposited over the antireflective coating 208. Depositing the anti-reflective coating 208 over the entire surface 202a has the advantage of reducing the number of process steps required to manufacture the optical element 220 . This is because it is not necessary to deposit an anti-reflective coating on selective portions on the surface 202a as in FIG. 2A. The antireflective coating 208 is typically very thin and does not interfere with the performance of the reflective coating 206.

For example, ion-assisted electron beam (E-beam) deposition as described above can be used to deposit a single layer of hafnium oxide having a desired thickness and composition. In one embodiment, a 10 nm single layer of hafnium oxide anti-reflective coating 208 is deposited over the entire surface 202a of the silicon substrate 202 to minimize the reflection of light having a wavelength of 193 nm. The reflective coating 206 can be deposited on the antireflective coating 208 using techniques such as sputtering, chemical vapor deposition (CVD), or physical vapor deposition (PVD).

FIG. 3A illustrates the reflective properties of the reflective coating 206 according to one embodiment of the present invention. With the reflective coating 206 deposited on the substrate surface 202a, the incident light 320a is substantially entirely reflected as a beam 322, with a negligible amount of light reaching the substrate 202a through the reflective coating 206. An anti-reflective coating 208 is used to prevent light reflected from the surface 202a from interfering with light reflected from the reflective coating 206.

FIG. 3B schematically illustrates the reflective properties of the anti-reflective coating 208 according to one embodiment of the present invention. The light beam 325 incident on the surface 208 a of the antireflection coating 208 is reflected as a beam 326. The light beam 325 also partially passes through the antireflective coating 208 and is reflected from the surface 202a as a beam 324. According to one embodiment of the present invention, the composition and thickness of the anti-reflective coating 208 causes the peaks and valleys of the beam 326 and beam 324 to destructively interfere so that the reflection of incident light 325 is negligible. . Beam 326 includes peaks 326a, valleys 326b, and peaks 326c. Beam 324 includes valleys 324a, peaks 324b, and valleys 324c. As shown in FIG. 3B, the peaks and valleys of beam 326 and beam 324 have opposite phases, which causes destructive interference. The peaks 326a and valleys 324a interfere destructively. Similarly, peaks 324b and valleys 326b, and peaks 326c and valleys 324c interfere destructively, thereby substantially eliminating reflection of incident light 325. In one embodiment, if the wavelength of incident light 325 is 193 nm and the underlying substrate 202 is silicon, the reflection produced by the 10 nanometer (nm) layer of hafnium oxide anti-reflective coating 208 is 0.2. Less than a percent.

FIG. 4 shows the percentage of reflection from an antireflective coating of hafnium oxide having a thickness of 10 nanometers for incident light having a wavelength range of 185 nm to 210 nm. As can be seen in FIG. 4, the percentage of reflection from the antireflective coating is lowest at about 193 nm for a specific composition of 10 nm thick hafnium oxide. Those skilled in the art will appreciate that the percentage of reflection at a particular wavelength is based on the composition and thickness of the materials used to form the anti-reflective coating and the underlying substrate and can vary based on the requirements of the implementation. Let's be recognized.

FIG. 5 shows an exemplary flowchart 500 illustrating the steps performed to produce an anti-reflective coating that substantially eliminates reflection of incident light, in accordance with one embodiment of the present invention. The flowchart 500 will be described with continued reference to the exemplary embodiments shown in FIGS. However, the flowchart 500 is not limited to these embodiments. Some steps shown in flowchart 500 are not necessarily performed in the order shown.

In step 502, a highly reflective metal layer is deposited over a portion of a silicon substrate. For example, a highly reflective coating of aluminum, aluminum oxide, or silicon oxide is deposited on the surface 202a of the substrate 202.

In step 504, the composition and thickness of the antireflective material that causes destructive interference of specific wavelengths of radiation reflected from the surface of the antireflective material and the underlying substrate is determined. For example, the composition and thickness of the anti-reflective coating 208 is determined such that the beam 325 reflected from the surface 208 a interferes with the beam 324 reflected from the surface 202 a of the substrate 202. In one embodiment, a 10 nm thick hafnium oxide composition that causes destructive interference of 193 nm incident light is used.

In step 506, an anti-reflective layer of the determined composition and thickness is deposited on the portion of the silicon substrate not covered by the metal layer described in step 502. For example, an anti-reflective coating 208 of a determined thickness (10 nm) and composition (hafnium oxide) is deposited on the portion 202a of the silicon substrate 202 that is not covered by the reflective coating 206. Depositing hafnium oxide by evaporating hafnium in the deposition chamber and introducing a controlled amount of oxygen into the deposition chamber to form an antireflective coating of hafnium oxide of a determined thickness and composition Can do. In some cases, ion assistance is used to control the composition of hafnium oxide. Using a technique such as sputtering, CVD, or PVD, a highly reflective metal layer can be deposited on the surface. The reflective layer can include one or more of aluminum, aluminum oxide, silicon oxide, and metal fluoride compounds. The reflective layer is substantially reflective to certain incident radiation, such as 193 nm.

IV. Conclusion
It will be appreciated that the detailed description section, rather than the means for solving the problem and the abstract section, is intended for use in interpreting the claims. The means for solving the problem and the summary section specify one or more exemplary embodiments of the invention as envisaged by the inventor (s), but all exemplary embodiments are It is not expressly stated and is therefore not intended to limit the invention and the scope of the claims.

The present invention has been described above using a function building block indicating the implementation of the specified functions and relationships. For convenience of explanation, the boundaries of these functional building blocks are arbitrarily defined in this specification. Alternative boundaries can be defined as long as the specified functions and relationships are properly performed.

The general description of the invention will become more fully apparent from the foregoing description of specific embodiments. The overall nature of this particular nature is determined by the application of knowledge in the art, without undue experimentation, by other persons without departing from the general concept of the invention. The form can be easily changed and / or adapted for various applications. Accordingly, based on the teachings and guidance presented herein, such adaptations and modifications are intended to be within the meaning and scope of equivalents of the disclosed embodiments. It will be understood that the terms and terminology herein are for purposes of description and not limitation and that the terms and predicates herein will be interpreted by one of ordinary skill in the art in view of their teachings and guidance.

The breadth and scope of the present invention is not limited to any of the above-described exemplary embodiments, but is to be defined only in accordance with the claims and their equivalents.

DESCRIPTION OF SYMBOLS 100 ... Lithographic apparatus, 200, 220 ... Optical element, 202 ... Silicon substrate, 202a ... Surface, 206 ... Reflective coating, 208 ... Antireflection coating, 208a ... Surface, 320a ... Incident light, 322, 324, 326 ... Beam, 324a 324c ... Valley, 324b ... Mountain, 325 ... Light beam, 326 ... Beam, 326a, 326c ... Mountain, 326b ... Valley, AD ... Adjuster, B ... Radiation, BD ... Beam delivery system, C ... Target part, CO ... Capacitor , IF ... position sensor, IF1, IF2 ... position sensor, IL ... illuminator, IN ... integrator, M1 ... mask alignment mark, MA ... patterning device (mask), MP ... mask pattern, MT ... mask table (support structure), P1 ... PC board alignment mark, PD ... Aperture device, PM ... positioner, PPU ... pupil, PS ... projection system, PW ... positioner, SO ... radiation source, W ... substrate, WT ... substrate table

Claims (6)

A silicon substrate;
A reflective layer disposed on a first portion of the surface of the silicon substrate;
An antireflective layer that is a single layer disposed on a second portion different from the first portion of the surface of the silicon substrate;
The reflective layer is substantially reflective to radiation having a wavelength of 193 nm;
The antireflection layer is made of hafnium oxide (HfO _x ) having a thickness of 10 nm ,
The light reflected from the antireflective layer and the light reflected from the silicon substrate under the antireflective layer interfere with each other in a destructive manner to substantially reflect the radiation of a predetermined wavelength incident on the antireflective layer. An optical element used in MEMS, configured to eliminate. A silicon substrate;
An antireflective layer that is a single layer disposed on the surface of the silicon substrate;
A reflective layer disposed on the surface portion of the antireflection layer, and
The antireflection layer is made of hafnium oxide (HfO) having a thickness of 10 nm. _x )
The reflective layer is substantially reflective to radiation having a wavelength of 193 nm;
The light reflected from the antireflective layer and the light reflected from the silicon substrate under the antireflective layer interfere with each other in a destructive manner to substantially reflect the radiation of a predetermined wavelength incident on the antireflective layer. An optical element used in MEMS, configured to eliminate. The reflective layer is aluminum, oxides of aluminum, comprises one or more oxides and the metal fluoride compound of silicon, the optical element according to claim 1 or 2. A lithographic apparatus comprising an optical element according to any one of the preceding claims. A method for manufacturing an optical element used in MEMS, comprising:
Disposing a reflective layer on the first portion of the surface of the silicon substrate;
Placing an anti-reflection layer is a single layer on a different second portion and said first portion of said surface of said silicon substrate,
With
In the step of disposing the reflective layer,
Determining the composition of the reflective layer to be substantially reflective to radiation at a wavelength of 193 nm;
In the step of disposing the antireflection layer,
Depositing hafnium oxide (HfO _x ) using an ion-assisted electron beam to a thickness of 10 nm while controlling the oxygen content;
As a result, the light reflected from the antireflection layer and the light reflected from the underlying silicon substrate interfere with each other in a destructive manner to substantially eliminate reflection of radiation having a predetermined wavelength incident on the antireflection layer. A method of manufacturing the optical element configured to: Wherein the step of disposing the anti picolinimidate is, aluminum, oxides of aluminum, is to place one or more oxides and the metal fluoride compound of silicon, The method of claim 5.