JP2012033925A - Exposure equipment, exposure method, and device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve a fine pattern on a wafer.SOLUTION: An illumination optical system IOP switches (or simultaneously) first and second lights of different wavelengths to irradiate a reticle R1 having a first pattern positioned on a first surface and a reticle R2 having a second pattern positioned on a second surface via a sub optical system 60 with the lights as an illumination light IL. An image of a composite pattern composed of a part where the first and second patterns are overlapped is formed on a wafer W held by a wafer stage WST on the image surface. Therefore, when first and second resist layers having sensitivity to the first and second lights are formed on an object, an image of a composite pattern composed of a part where the first and second patterns are overlapped is formed on the first and second resist layers by irradiating the reticles R1 and R2 respectively with the first and second lights simultaneously as an illumination light.

Description

  The present invention relates to an exposure method, an exposure apparatus, and a device manufacturing method, and more particularly, to an exposure method and an exposure apparatus used in a lithography process for manufacturing a semiconductor element (such as an integrated circuit) and a liquid crystal display element, and the exposure method or The present invention relates to a device manufacturing method using an exposure apparatus.

  Conventionally, in a lithography process for manufacturing electronic devices (microdevices) such as semiconductor elements (integrated circuits, etc.), liquid crystal display elements, etc., a step-and-repeat type projection exposure apparatus (so-called stepper) or a step-and-scan type Projection exposure apparatuses (so-called scanning steppers (also called scanners)) are mainly used.

  As semiconductor devices are highly integrated, the patterns are gradually miniaturized. To cope with the miniaturization of patterns, the exposure wavelength is shortened and the numerical aperture of the projection optical system is increased (high NA). Etc.) have been attempted. For example, the exposure wavelength is shortened to 193 nm of an ArF excimer laser, and the numerical aperture exceeds 1 in the case of a so-called immersion exposure apparatus. However, the demand for higher integration of semiconductor elements does not stop, and along with this, the exposure apparatus is required to further improve the resolution, and now it is finer than the resolution limit of the projection exposure apparatus. It has been demanded that a simple pattern image can be formed on a substrate (wafer). As an effective countermeasure for this, a so-called double patterning method (see, for example, Patent Document 1), a cutting exposure method, and the like have recently been performed.

  However, in a conventional exposure apparatus, for example, when performing a cutting exposure, it is necessary to prepare a plurality of reticles each formed with a cutting pattern, and process processes such as etching are required as many times as the number of the reticles. There was a point that should be improved. On the other hand, the demand for miniaturization of semiconductor device patterns is not known, and in order to cope with further miniaturization in the future, it is possible to reduce the cost required for resources such as reticles and / or improve throughput, The appearance of a new exposure apparatus that can form a pattern finer than the resolution limit on a wafer has been desired.

International Publication No. 2008/059440

  According to a first aspect of the present invention, there is provided an exposure apparatus that exposes an object to form a pattern on the object, the first light having a first wavelength and the second light having a second wavelength different from the first wavelength. The illumination light is switched to or simultaneously with the first mask having the first pattern disposed on the first surface and the second mask having the second pattern disposed on the second surface. An image of a composite pattern that includes at least a component that can irradiate and optimize chromatic aberration with respect to the first and second lights, and includes an overlapping portion of the first pattern and the second pattern. An exposure apparatus comprising: an optical system that can be formed on the first mask; a first holding member that holds the first mask; a second holding member that holds the second mask; and a third holding member that holds the object. Is provided.

  According to this, the first mask having the first pattern, which is held on the first surface and is held by the first holding member, is switched or simultaneously switched between the first light and the second light by the optical system, and The second mask having the second pattern held by the second holding member and disposed on the second surface is irradiated as illumination light. Then, an image of a composite pattern composed of the overlapping portion of the first pattern and the second pattern is formed on the object held on the image plane by the third holding member. Accordingly, when a photosensitive layer is formed on the object, the photosensitive layer is exposed with the image of the composite pattern. In particular, when the photosensitive layer is formed with first and second resist layers having sensitivity to the first light and the second light, respectively, the first light and the second light are simultaneously applied to the first light and the second light. By irradiating each of the first mask and the second mask as illumination light, a composite composed of overlapping portions of the image of the first pattern irradiated with the first light and the image of the second pattern irradiated with the second light. Pattern images are formed on the first and second resist layers.

  According to the second aspect of the present invention, using the exposure apparatus of the present invention, an object is exposed to form an image of a composite pattern composed of an overlapping portion of the first pattern and the second pattern on the object. And a device manufacturing method comprising: developing the exposed object.

  According to a third aspect of the present invention, there is provided an exposure method in which an object is exposed to form a pattern on the object. A first photosensitive layer having low sensitivity to second light having two wavelengths and a second photosensitive layer having high sensitivity to the second light and low sensitivity to the first light are stacked on the object. Illuminating the first pattern with the first light, irradiating the object with the first light via the first pattern via the first optical system, and Exposing a layer to form a latent image of the first pattern; illuminating the second pattern with the second light; and illuminating light through the second pattern including a first optical system. And irradiating the object through two optical systems and exposing the second photosensitive layer to form a latent image of the second pattern. When exposure method comprising is provided.

  According to this, it is possible to form a fine pattern on the object, which is a pattern of the overlapping portion of the first and second patterns.

  According to a fourth aspect of the present invention, there is provided a device manufacturing method comprising: forming a pattern on an object by the exposure method of the present invention; and developing the object on which the pattern is formed. .

It is a figure which shows schematically the structure of the exposure apparatus of 1st Embodiment. FIG. 2 is a block diagram showing an input / output relationship of a main controller that mainly constitutes a control system in the exposure apparatus of FIG. 1. FIG. 3A shows an example of an exposure pattern, FIGS. 3B and 3C show a combination of two patterns used in the super-resolution exposure method, and FIG. FIG. 3E is a diagram showing a superimposed image of two patterns in the resolution exposure method, FIG. 3E is a diagram showing a cross section of the super-resolution pattern formed on the wafer by the super-resolution exposure method, and FIG. It is a figure which shows intensity distribution of two illumination lights in a super-resolution exposure method. FIG. 4A and FIG. 4B are diagrams showing an example of an exposure pattern and a mask pattern used in combination in the super-resolution exposure method, respectively. FIGS. 5A and 5B are diagrams showing combinations of the two patterns of FIGS. 4A and 4B. It is a figure which shows schematically the structure of the exposure apparatus of 2nd Embodiment. FIG. 7 is a block diagram showing an input / output relationship of a main controller that mainly constitutes a control system in the exposure apparatus of FIG. 6.

<< First Embodiment >>
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 5B.

FIG. 1 shows a schematic configuration of an exposure apparatus 100 according to the first embodiment. The exposure apparatus 100 is a step-and-scan projection exposure apparatus, a so-called scanner. As will be described later, in the present embodiment, the projection optical system PL is provided. Therefore, in the following, the direction parallel to the optical axis AXp of the projection optical system PL is the Z-axis direction, and the first in the plane perpendicular to the Z-axis direction. The scanning direction in which the two reticles (R2 ₁ or R2 ₂ ) and the wafer W are relatively scanned is defined as the Y-axis direction, the direction orthogonal to the Z-axis and the Y-axis is defined as the X-axis direction, and the X-axis, Y-axis, and Z-axis directions. The rotation (tilt) direction will be described as θx, θy, and θz directions, respectively.

The exposure apparatus 100 holds an illumination optical system IOP and a first reticle R1 connected to a light source unit 50 (not shown in FIG. 1, refer to FIG. 2) via a light transmission optical system (not shown), on an XY plane. First reticle stage RST 1 that moves in a parallel plane, and second reticle stage RST 2 and first reticle R 1 that move in a plane parallel to the XY plane while simultaneously holding _two second reticles R 2 ₁ and R _{2 2} . pattern surface and a second reticle R2 ₁ or R2 ₂ of the pattern surface and the sub projection optical system which in an optically conjugate relationship (hereinafter, subordinate optical abbreviated as system) 60, an image of the pattern formed on the second reticle Projection unit PU that projects the image onto wafer W, wafer stage WST that holds wafer W and moves in the XY plane, and their control system, as well as sub optical system 60, projection unit PU, and the first and second records. A body BD such cycle stage RST1, RST2, and the like are mounted, comprises.

As shown in FIG. 2, the light source unit 50 switches between the first light source 52 and the second light source 54, and the first and second lights IL ₁ and IL ₂ having different wavelengths emitted from the two light sources. Or a switching device 56 that transmits light to the illumination optical system IOP via the light transmission optical system at the same time. The switching device 56 is controlled by the main control device 120.

  Here, for convenience of explanation, the body BD will be briefly described prior to other components.

The body BD includes a main body column 30 installed on the floor surface F and an optical system support column 35 installed on the main body column 30. Body column 30 has a plurality arranged in a predetermined positional relationship on the floor surface F, a leg portion 33 ₁ for example, four, and a body frame 32 supported horizontally by legs 33 ₁ of the plurality of ing. The main body frame 32, a predetermined shape with a predetermined thickness, for example, a rectangular plate member, by its -Y side end, for example, two legs 33 ₁ while being supported from below, the Y-axis direction portion somewhat + Y side from the center is supported from below by the legs 33 _1, for example two. Of the main body frame 32, the slightly + Y side position from the leg portion 33 ₁ of the + Y side, the opening 32a of the passage of the illumination light IL to be described later is formed. Further, the body frame 32, + the substantially central portion of the leg portion 33 ₁ of the Y-side of the leg portion 33 ₁ and the -Y side, and is opened 32b for the upper portion of the projection unit PU is inserted therein is formed Yes. Optical system support column 35 includes a leg portion 33 ₂ which is fixed to an end portion of the + Y side of the main frame 32 the upper surface, and a support frame 31 which is fixed in a cantilever state on the leg 33 ₂ .

The illumination optical system IOP is disposed below the + Y side of the leg portion 33 ₁ of the + Y side and the main body frame 32 of the main body column 30 on the floor surface F. The illumination optical system IOP converts the first light IL ₁ and / or the second light IL ₂ sent from the light source unit 50 through the light transmission optical system to the illumination light IL through an optical integrator (not shown). X on a first surface (coincident with the pattern surface of the first reticle R1) that is conjugated to the field stop placement surface that is transformed and set (or limited) by a field stop (not shown) (also called a reticle blind or masking system) A slit-like illumination area IAR1 elongated in the axial direction (the direction orthogonal to the paper surface in FIG. 1) is illuminated with illumination light (exposure light) IL with substantially uniform illuminance through the opening 32a and the opening RB1a described later. To do. The configuration of the illumination optical system IOP is the same as the illumination optical system disclosed in, for example, US Patent Application Publication No. 2003/0025890. In the present embodiment, the first light IL ₁ and to for example a KrF excimer laser beam (wavelength 248 nm) is the second light IL ₂ and to for example ArF excimer laser light (wavelength 193 nm) have been used respectively.

The first reticle stage RST1 is in a non-contact state on a first reticle base RB1 disposed above (+ Z side) the illumination optical system IOP via a plurality of gas static pressure bearings provided on the bottom surface, for example, air bearings. It is supported by. The first reticle base RB1 is disposed in the horizontal (parallel to the XY plane) on substantially directly above the main body frame 32 of the exit end illumination optical system IOP, supported by the body frame 32 via a plurality of vibration isolator 32 ₀ Has been.

The first reticle stage RST1 is driven in the X and Y two-dimensional directions on the first reticle base RB1 by a first reticle stage drive system 11 ₁ (not shown in FIG. 1, see FIG. 2) including a linear motor, for example. Thus, it can be rotated slightly in the θz direction. Location information within the XY plane of the first reticle stage RST1 (including rotation information in the θz direction), the first reticle laser interferometer (hereinafter, "first reticle interferometer") 14 _1, the movable mirror ₁₂ 1 ( Alternatively, it is always detected with a resolution of, for example, about 0.25 nm via a reflective surface formed on the end surface of the first reticle stage RST1. The first measurement information of reticle interferometer 14 _1, the main controller 120 (not shown in FIG. 1, see FIG. 2) is supplied to the. The main control unit 120, based on the measurement information from the first reticle interferometer 14 _1, Y-axis position and the X-axis direction position of the first reticle stage RST1 via a first reticle stage drive system 11 _1, In addition, the rotation in the θz direction is controlled.

  On the first reticle stage RST1, the first reticle R1 is placed with its pattern surface facing upward (+ Z side), that is, on the side opposite to the illumination optical system IOP. This pattern surface coincides with the first surface described above, that is, a surface conjugate with the field stop arrangement surface in the illumination optical system IOP. The first reticle R1 can also be held on the first reticle stage RST1 with its pattern surface facing downward (−Z side). In this case, however, the pattern surface has the pattern surface within the illumination optical system IOP. Therefore, it is necessary to match the conjugate plane with the field stop arrangement surface.

  The first reticle base RB1 is formed with an opening RB1a penetrating in the Z-axis direction. The opening RB1a is substantially opposed to the above-described opening 32a.

  The illumination light IL emitted from the illumination optical system IOP sequentially passes through the opening 32a of the main body frame 32, the opening of the first reticle base RB1, and the opening (not shown) of the first reticle stage RST1, and then the first reticle R1. The pattern surface (+ Z side surface) is irradiated.

Secondary optical system 60 is supported in a suspended state (parallel to the XY plane) Horizontal via a plurality of vibration isolator 31 ₀ to the support frame 31 of the optical system support column 35. The sub optical system 60 is vibrationally separated from the optical system support column 35. The sub optical system 60 has a plurality of optical elements (lens elements (referred to as slave lenses in distinction from lens elements constituting the projection optical system PL described later)) arranged along the optical axis. The sub optical system 60 is, for example, a catadioptric system that is telecentric on both sides and has a projection magnification of 1 ×. The pattern surface of the first reticle R1 is arranged on the first surface (object surface) of the sub optical system 60, and the pattern surface of the second reticle R2 (R2 ₁ or R2 ₂ ) described later is arranged on the second surface (image surface). Is done. Therefore, the illumination light IL via the first reticle R1 is transmitted by the sub optical system 60 toward the second reticle R2 (R2 ₁ or R2 ₂ ).

Secondary optical system 60 is provided with its imaging characteristics, for example, the first imaging characteristic correction device 41 ₁ to adjust the aberrations. First imaging characteristic correction device 41 ₁ corrects the aberration of the secondary optical system 60 according to the wavelength of the illumination light IL (that is, the optical _IL 1, IL _2), focused on the pattern surface of the second reticle R2 This is used to adjust the image formation state of the pattern of the pattern of the first reticle R1 to be maintained or to maintain it well. First imaging characteristic correction apparatus 41 ₁ includes a lens element of the inclined drivable part against the fine drive and the optical axis in a direction parallel to the optical axis by an actuator such as a piezoelectric element, the driving amount of the actuator It includes a sensor such as an encoder for measuring, and a controller for controlling the actuator based on the measurement result. The controller controls the actuator in accordance with an instruction from main controller 120. First imaging characteristic correction device 41 _1, the optical properties of the secondary optical system 60, for example, spherical aberration (aberration of the imaging position), coma (aberration of magnification), astigmatism, field curvature, distortion Various aberrations (imaging characteristics) such as (distortion) can be adjusted. In the present embodiment, the imaging characteristics of the sub optical system 60 are initially adjusted in advance according to one wavelength of the lights IL ₁ and IL ₂ , and the first imaging is used when the other light is used as the illumination light IL. It is set to adjust the imaging characteristic by using the characteristic correction device 41 _1. In this case, when one of the lights is used again as the illumination light IL, the initial adjustment state may be restored. However, in the case of using light of any wavelength, it is desirable to correct the distortion of the pattern image due to the thermal expansion deformation of the first reticle R1, the thermal expansion deformation of the lens, etc. as in the conventional case. For correction of distortion of the pattern image due to thermal expansion deformation of the lens, for example, a method disclosed in US Patent Application Publication No. 2008/0218714 can be applied.

  The position of the sub optical system 60 is measured by a displacement measurement system 61 (not shown in FIG. 1, see FIG. 2), and the measurement information is supplied to the main controller 120 (see FIG. 2). Based on the measurement information from the displacement measurement system 61, the main controller 120 drives the first and second reticle stages RST1 and RST2 relative to the sub optical system 60, thereby changing the position of the sub optical system 60. Therefore, the formation error of the pattern image is corrected.

The second reticle stage RST2 is not mounted on the second reticle base RB2 disposed below (−Z side) of the sub optical system 60 via a plurality of gas static pressure bearings, for example, air bearings, provided on the bottom surface thereof. Supported in contact. The second reticle base RB2 is supported horizontally (parallel to the XY plane) through a plurality of vibration isolator 32 ₀ to the body frame 32.

Position information (including rotation information in the θz direction) of the second reticle stage RST2 in the XY plane is transferred by the second reticle laser interferometer (hereinafter referred to as “second reticle interferometer”) 14 ₂ to the movable mirror 12 ₂ ( Alternatively, it is always detected with a resolution of, for example, about 0.25 nm via a reflecting surface formed on the end surface of the second reticle stage RST2. Second measurement information of reticle interferometer 14 _2, the main controller 120 (not shown in FIG. 1, see FIG. 2) is supplied to the. The main control unit 120, based on the measurement information from the second reticle interferometer 14 _2, second reticle stage drive system that is configured similarly to the first reticle stage drive system 11 ₁ 11 2 _(not shown in FIG. 1, 2), the position of the second reticle stage RST2 in the Y-axis direction, the position in the X-axis direction, and the rotation in the θz direction are controlled.

The second reticle stage RST2 is a so-called double reticle holder type reticle stage disclosed in, for example, US Pat. No. 6,327,022, and two second reticles R2 ₁ and R2 ₂ are moved in the Y-axis direction. Can be placed side by side. Two second reticles R2 ₁ and R2 ₂ are placed on the second reticle stage RST2 with the pattern surface facing downward (−Z side). When the illumination area IAR1 on the first reticle R1 is illuminated by the illumination light IL, the illumination light IL transmitted through the first reticle R1 is irradiated to the second reticle R2 via the sub optical system 60, and is conjugate with the illumination area IAR1. The illumination area IAR2 on the second reticle R2 (R2 ₁ or R2 ₂ ) is illuminated. Note that the second reticles R2 ₁ and R2 ₂ can be held on the second reticle stage RST2 with their pattern surfaces facing upward (+ Z side). It is necessary to make the image planes of the optical system 60 coincide.

Projection unit PU is arranged below (−Z side) second reticle stage RST2. The projection unit PU is supported by a lens barrel surface plate (also referred to as a metrology frame) 38 via a flange FLG that is integrally provided at substantially the center in the height direction of the housing 40. Barrel platform 38 is supported suspended horizontally (parallel to the XY plane) through a plurality of vibration isolator 33 ₀ to the body frame 32. The lens barrel surface plate 38 is vibrationally separated from the main body frame 32.

  The projection unit PU has a portion below the flange FLG inserted into a circular opening formed in the lens barrel base plate 38 (or a stepped circular opening with which the lower end of the flange FLG engages), and the upper part is described above. The upper end portion is inserted into a recess formed in the bottom surface of the second reticle base RB2. The projection unit PU is not in contact with members other than the lens barrel surface plate 38.

  The second reticle base RB2 is formed with an opening RB2a serving as a path for the illumination light IL. For this reason, the illumination light IL transmitted through the second reticle R2 enters the projection optical system PL, which will be described later, sequentially through an opening (not shown) of the second reticle stage RST2 and an opening RB2a of the second reticle base RB2. .

  The projection unit PU includes a housing 40 and a plurality of optical elements (lens elements (a slave lens constituting the sub optical system 60 described above) as a master lens) arranged in the housing 40 along the optical axis AXp. And a projection optical system PL consisting of:

  The projection optical system PL is, for example, both-side telecentric and has a predetermined projection magnification (for example, 1/4 times, 1/5 times, or 1/8 times). For this reason, when the illumination area IAR2 on the second reticle R2 is illuminated by the illumination light IL transmitted through the first reticle R1, the illumination light IL transmitted through the second reticle R2 is incident on the wafer W via the projection optical system PL. A reduced image of the composite pattern that is irradiated and overlaps the pattern in the illumination area IAR1 on the first reticle R1 and the pattern in the illumination area IAR2 on the second reticle R2 is formed on the image plane of the projection optical system PL. The image is formed on the wafer W placed in the position.

The projection optical system PL is provided with a _second imaging characteristic correction device 412 that adjusts its imaging characteristics, for example, aberrations. However, it is desirable that the projection optical system PL be suppressed to a level where there is chromatic aberration for both the _first and _second lights IL ₁ and IL ₂ . Second imaging characteristic correction device 41 ₂ has the same configuration as the first imaging characteristic correction device 41 ₁ described above, function similarly. However, towards the second imaging characteristic correction device 41 _2, the number of adjustment amount is large, it is possible to more finely adjusted. Here, as a calculation method of the adjustment amount for correcting the imaging characteristics of the imaging characteristics correction apparatuses 41 ₁ and 41 ₂ , for example, US Patent Application Publication No. 2002/0159040, US Patent Application Publication No. 2006 / A calculation method using a relational expression such as wavefront aberration (coefficient of each term of Zernike polynomial), Zernike sensitivity, adjustment amount, etc. disclosed in the specification of US Pat. No. 0007418, US Patent Application Publication No. 2005/0206850 is used. be able to.

A resist (photosensitive material) is applied to the surface of the wafer W. A reduced image of a composite pattern composed of overlapping portions of the pattern in the illumination area IAR1 on the first reticle R1 and the pattern in the illumination area IAR2 on the second reticle R2 is on the wafer W conjugate to the illumination areas IAR1 and IAR2. It is projected onto an area (hereinafter also referred to as an exposure area) IA. By synchronously driving the first and second reticle stages RST1 and RST2 and the wafer stage WST, the first and second reticles R1 and R2 (R2 ₁ and R2 ₂ ) are moved with respect to the illumination areas IAR1 and IAR2 (illumination light IL). By relatively driving in the scanning direction (Y-axis direction) and simultaneously driving the wafer W relative to the exposure area IA (illumination light IL) in the scanning direction (Y-axis direction), one shot area on the wafer W ( divided area) is scanned and exposed, combined pattern in which the first reticle R1 in the shot area consisting of the second reticle R2 ₁ or R2 ₂ overlap portion is transferred.

  Returning to FIG. 1, wafer stage WST is driven on stage base 22 with a predetermined stroke in the X-axis direction and Y-axis direction by stage drive system 24 (not shown in FIG. 1, see FIG. 2) including a linear motor and the like. At the same time, it is slightly driven in the Z-axis direction, θx direction, θy direction, and θz direction. On wafer stage WST, wafer W is held, for example, by vacuum suction or the like via a wafer holder (not shown). Wafer stage WST is not limited to a single 6-degree-of-freedom drive stage, and may be configured by a plurality of stages that can drive wafer W with 6 degrees of freedom by combining the drive directions of the respective stages.

  Position information of wafer stage WST in the XY plane (including rotation information (yaw amount (rotation amount θz in θz direction), pitching amount (rotation amount θx in θx direction), rolling amount (rotation amount θy in θy direction))) Is resolved by a laser interferometer system (hereinafter abbreviated as “interferometer system”) 18 via a movable mirror 16 (or a reflection surface formed on the end surface of wafer stage WST), for example, about 0.25 nm. Always detected. Measurement information of the interferometer system 18 is supplied to the main controller 120 (see FIG. 2). Main controller 120 controls the position (including rotation in the θz direction) of wafer stage WST in the XY plane via stage drive system 24 based on measurement information from interferometer system 18.

  Further, the position and inclination of the surface of the wafer W in the Z-axis direction are determined by, for example, a focus sensor AF (see FIG. 5) comprising an oblique incidence type multi-point focus position detection system disclosed in US Pat. No. 5,448,332. 1 (not shown, see FIG. 2). The measurement information of the focus sensor AF is also supplied to the main controller 120 (see FIG. 2).

  A wafer alignment system (hereinafter referred to as an alignment system) AS (not shown in FIG. 1, see FIG. 2) for detecting alignment marks and the like formed on the wafer W is provided on the side surface of the projection unit PU. As an example of the alignment system AS, an FIA (Field Image Alignment) system, which is a kind of image processing type imaging alignment sensor, is used.

  In the exposure apparatus 100, a TTR (Through The Reticle) alignment system using light having an exposure wavelength disclosed in, for example, US Pat. No. 5,646,413 is also provided above the second reticle stage RST2. A pair of reticle alignment systems 13 (not shown in FIG. 1, refer to FIG. 2) is provided. The detection signal of the reticle alignment system 13 is supplied to the main controller 120 (see FIG. 2).

  FIG. 2 is a block diagram showing the input / output relationship of the main controller 120 that mainly constitutes the control system of the exposure apparatus 100 of the present embodiment. The main controller 120 includes a so-called microcomputer (or workstation) comprising a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and controls the entire apparatus. Control.

  Next, the operation of the exposure apparatus 100 of the present embodiment configured as described above will be briefly described. Here, as an example, a case will be described in which only one second reticle R2 is mounted on second reticle stage RST2.

  Prior to exposure, the first reticle R1 is loaded onto the first reticle stage RST1 by a reticle loader (not shown). At the same time, the second reticle R2 is loaded onto the second reticle stage RST2. Further, a wafer W having a photosensitive layer (resist layer) formed on the surface thereof by a coater / developer (not shown) provided in the exposure apparatus 100 is transferred to a wafer holder (not shown) of wafer stage WST by a wafer loader (not shown). Loaded on top.

  Thereafter, like the normal scanner, the main controller 120 uses the pair of reticle alignment systems 13, a reference mark plate (not shown) on the wafer stage WST, the alignment system AS, and the like to use the reticle of the second reticle R2. Alignment, baseline measurement of the alignment system AS, and the like are performed. Subsequent to these preparation operations, the main controller 120 executes wafer alignment (alignment measurement) such as so-called multi-shot EGA within a shot.

  The reticle alignment and the baseline measurement of the alignment system AS are disclosed in detail in, for example, US Pat. No. 5,646,413, and the subsequent in-shot multipoint EGA is disclosed in, for example, US Pat. , 876,946 and the like.

  Based on the in-shot multipoint EGA, an array coordinate of shot areas on the wafer and a deformation amount (magnification, rotation, orthogonality) including the magnification of each shot area are obtained.

Therefore, the main controller 120 sets the sub optical system 60 and the projection optical system PL using the first and second imaging characteristic correction devices 41 ₁ and 41 ₂ as necessary based on the wavelength of the illumination light IL. The lens elements constituting each are driven to correct the imaging characteristics (aberration) of the sub optical system 60 and the projection optical system PL. At this time, the main control device 120 also takes into account the amount of deformation (magnification, rotation, orthogonality) including the magnification of each shot area obtained by the above-described multi-point EGA in the shot, and the like to perform the second imaging characteristic correction. It corrects the aberration of the projection optical system PL by using the device 41 _2.

  Main controller 120 determines wafer stage WST as a wafer based on the alignment coordinates of the shot area on wafer W obtained by alignment measurement (multi-point EGA in a shot) and the baseline of alignment system AS previously measured. The stepping operation for moving to the scanning start position of each shot area on W, and the second reticle stage RST2 and wafer stage WST are opposite to each other along the Y-axis direction at a speed ratio corresponding to the projection magnification of the projection optical system PL. At the same time, the second reticle stage RST2 and the first reticle stage RST1 are synchronously moved at the same speed along the Y-axis direction, and the scanning exposure operation is repeated, so that all shot areas on the wafer W are moved to the first shot area. Each of the composite pattern images formed by overlapping the pattern of the first reticle R1 and the pattern of the second reticle R2 To copy.

  Next, a first exposure method performed by the exposure apparatus 100 will be described.

  Here, a case where the pattern RP0 shown in FIG. 3A is transferred (formed) to each shot area on the wafer W will be taken up.

In this case, prior to the reticle alignment, on the second reticle stage RST2, a second reticle R2 ₁ which pattern RP1 is formed as shown in FIG. 3 (B), the pattern RP2 that shown in FIG. 3 (C) formed a second reticle R2 ₂ that is is loaded. Here, the pattern RP1 is a horizontally long rectangular opening pattern, and the length (dimension) in the direction orthogonal to the longitudinal direction is determined using the second light IL ₂ (ArF excimer laser light having a wavelength of 193 nm). The resolution limit is set to the same level as when projected onto the image plane through the projection optical system PL.

The pattern RP2 is a pattern in which two square opening patterns are arranged at a predetermined interval, and each opening pattern is projected using the first light IL ₁ (KrF excimer laser light having a wavelength of 248 nm). This is a size that can be resolved without any problem when projected onto the image plane via the optical system PL. However, the interval between the two square opening patterns is smaller than the resolution limit when the second light IL ₂ (ArF excimer laser light having a wavelength of 193 nm) is projected onto the image plane through the projection optical system PL. It is a length (dimension).

  On the first reticle stage RST1, a transmission type reticle having a rectangular opening pattern having a size and a shape corresponding to each shot area on the wafer is loaded as the first reticle R1.

Further, a wafer W is loaded on wafer stage WST. On top of wafer W, as shown in FIG. 3F, resist layer RG1 for optical IL ₂ (ArF excimer laser) and A resist layer RG2 for optical IL ₁ (KrF excimer laser) is laminated. The resist layers RG1 and RG2 have different photosensitive wavelengths (wavelength dependence). That is, the resist layer RG1 is sensitive by irradiation of the illumination light IL _2, low sensitivity to illumination light IL _1, not sensitive by irradiation of illumination light IL _1. On the other hand, the resist layer RG2 is sensitive by irradiation of the illumination light IL _1, less sensitivity to the illumination light IL _2, not sensitive by irradiation of illumination light IL _2.

Then, the above-described reticle alignment and baseline measurement of the alignment system AS and wafer alignment are executed. In this case, reticle alignment is performed on each of the second reticles R2 ₁ and R2 ₂ .

Then, based on the wavelength of the illumination light IL used for exposure (here, the light IL ₂ is used as the illumination light IL), lens elements that respectively constitute the sub optical system 60 and the projection optical system PL as necessary. And correction of aberrations of the projection optical system PL are performed.

Then, the main control unit 120, the second light source 54 is selected through the switching device 56, under the illumination light IL (light IL _2), using the first reticle R1, the second reticle R2 ₁ and the wafer W, respectively Then, the above-described step-and-scan exposure is performed. Thus, a second reticle R2 ₁ pattern RP1, pattern RP1 synthetic pattern (second reticle R2 ₁ consisting of overlapping portions of the opening pattern of the first reticle R1 is entirely contained in the opening pattern of the first reticle R1 Therefore, the image of the combined pattern becomes the same pattern as the pattern RP1) is transferred (formed) to all the shot areas on the wafer W. Figure 3 (E) signal waveform _{I 1} in indicates the light intensity of the aerial image of the pattern RP2. Thereby, the resist layer RG1 is exposed to the illumination light IL (light IL ₂ ), and in each shot area on the wafer W, the latent image RP1 ′ shown in FIG. 3D and FIG. It is formed. In FIG. _3E , symbol I _th indicates a threshold level at which the resist is exposed.

Next, on the basis of the wavelength of the illumination light IL used for exposure (here, the light IL ₁ is used as the illumination light IL), lens elements constituting the sub optical system 60 and the projection optical system PL, respectively, as necessary. And correction of aberrations of the projection optical system PL are performed.

Then, the main control unit 120, the first light source 52 is selected through the switching device 56, under the illumination light IL (light IL _1), using the first reticle R1, the second reticle R2 ₂ and the wafer W, respectively Then, the above-described step-and-scan exposure is performed. Thus, a second reticle R2 ₂ pattern RP2, pattern RP2 synthetic pattern (second reticle R2 ₁ consisting of overlapping portions of the opening pattern of the first reticle R1 is entirely contained in the opening pattern of the first reticle R1 Therefore, the image of the combined pattern is the same pattern as the pattern RP2) is transferred and formed on each of the entire shot areas on the wafer W so as to overlap the latent image RP1 ′. Figure 3 (E) the signal waveform _{I 2} in indicates the light intensity of the aerial image of the pattern RP2. Thereby, the resist layer RG2 is exposed to the illumination light IL (light IL ₁ ), and in each shot area on the wafer W, the latent image RP2 ′ shown in FIGS. It is formed.

As described above, using the illumination lights IL ₁ and IL ₂ having different wavelengths, the images of the patterns RP ₁ and RP ₂ of the second reticles R 2 ₁ and R _{2 2} are converted into resists having different photosensitive wavelengths (wavelength dependence) on the wafer W. The target pattern RP0 is resolved on the wafer W as a combined pattern thereof (a white pattern in FIG. 3A) by transferring it over the layers RG1 and RG2. Here, the pattern RP0 is a pattern that exceeds the resolution limit (finer than the wavelength of illumination light).

According to this first exposure method, the second reticle stage RST2 is loaded with _two second reticles R2 ₁ and R2 ₂ in advance, so that after the exposure of the first reticle is completed, reticle replacement, reticle alignment, etc. Without performing the above, exposure of the second reticle can be started simply by performing operations such as switching the light source and changing the illumination conditions and the like in accordance with the second reticle. That is, high-throughput double exposure using a reticle stage of a double reticle holder type is possible. High-throughput double exposure using a double reticle holder type reticle stage is disclosed in, for example, US Pat. No. 6,327,022.

  Next, a second exposure method performed by the exposure apparatus 100 will be described.

  Also in this case, the case where the pattern RP0 shown in FIG. 3A is transferred and formed in each shot area on the wafer W will be taken up.

  In this case, prior to reticle alignment, the main reticle CR shown in FIG. 4A in which the above-described patterns RP1 and RP2 are formed in a predetermined positional relationship is loaded on the second reticle stage RST2. On the first reticle stage RST1, a masking reticle MR in which an opening pattern MP shown in FIG. 4B is formed is loaded.

  Here, the main reticle CR is a transmissive reticle in which opening patterns corresponding to the patterns RP1 and RP2 are formed, and the masking reticle MR is a transmissive reticle in which an opening pattern MP is formed. The shape and size of the opening pattern MP are determined from the shapes and sizes of the patterns RP1 and RP2.

  On wafer stage WST, wafer W on which the aforementioned resist layers RG1 and RG2 are stacked is loaded. Then, the above-described reticle alignment and baseline measurement of the alignment system AS and wafer alignment are executed.

Then, based on the wavelength of the illumination light IL used for exposure (here, the light IL ₂ is used as the illumination light IL), lens elements that respectively constitute the sub optical system 60 and the projection optical system PL as necessary. And correction of aberrations of the projection optical system PL are performed.

Then, the second light source 54 is selected by the main controller 120 via the switching device 56, and the main reticle CR, the masking reticle MR, and the wafer W are respectively used under the illumination light IL (light IL ₂ ). The aforementioned step-and-scan exposure is performed. However, in this case, the relative position of the first reticle stage RST1 with respect to the second reticle stage RST2 is initially set as shown in FIG. 5A, so that the first reticle stage RST1 and the second reticle stage RST2 are the same. Scanning exposure is performed in synchronization with the speed. As a result, a composite pattern composed of an overlapping portion of the opening pattern MP of the masking reticle MR and the pattern RP1 of the main reticle CR, that is, an image of the pattern RP1 is transferred (formed) to each of all shot regions on the wafer W. . Thereby, the resist layer RG1 is exposed to the illumination light IL (light IL ₂ ), and in each shot area on the wafer W, the latent image RP1 ′ shown in FIG. 3D and FIG. It is formed.

Next, on the basis of the wavelength of the illumination light IL used for exposure (here, the light IL ₁ is used as the illumination light IL), lens elements constituting the sub optical system 60 and the projection optical system PL, respectively, as necessary. And correction of aberrations of the projection optical system PL are performed.

The first light source 52 is selected by the main controller 120 via the switching device 56, and the main reticle CR, the masking reticle MR, and the wafer W are used under the illumination light IL (light IL ₁ ). The above-described step-and-scan exposure is performed. However, in this case, the relative position of the first reticle stage RST1 with respect to the second reticle stage RST2 is initially set as shown in FIG. 5B, and the first reticle stage RST1 and the second reticle stage RST2 are the same. Scanning exposure is performed in synchronization with the speed.

As a result, a composite pattern composed of an overlapping portion of the pattern RP2 of the main reticle CR and the opening pattern MP of the masking reticle MR, that is, an image of the pattern RP2 is formed into a latent image RP1 ′ in each of all shot regions on the wafer W. Overlaid and transferred. Thereby, the resist layer RG2 is exposed to the illumination light IL (light IL ₁ ), and in each shot area on the wafer W, the latent image RP2 ′ shown in FIGS. It is formed.

As described above, in the second exposure method, the masking reticle MR is used to illuminate one of the pattern regions where the patterns RP1 and RP2 of the main reticle CR are formed using the corresponding illumination lights IL ₁ and IL _2. To do. Then, the patterns RP1 and RP2 are transferred onto the resist layers RG1 and RG2 having different photosensitive wavelengths (wavelength dependence) on the wafer W to transfer them as a composite pattern (a white pattern in FIG. 3A). The target pattern RP0 is resolved on the wafer W.

Also by the second exposure method described above, a pattern exceeding the resolution limit (finer than the wavelength of illumination light) can be resolved on the wafer, as in the first exposure method. In the second exposure method, one main reticle CR on which patterns RP1 and RP2 are formed and a masking reticle MR are used. Here, in the masking reticle MR, high accuracy is not required for forming the opening pattern MP. Therefore, a second reticle R2 ₁ in which the first pattern RP1 high precision is formed, when compared second and reticle R2 ₂ in which the second pattern RP2 precision is formed with a first exposure method using, reticle Expected to reduce manufacturing and management costs.

  In the second exposure method, only the minimum necessary illumination light through the aperture pattern MP is irradiated onto the main reticle CR, so that the main reticle is mostly light-shielding and has a high light absorption rate and easily expands. It is possible to minimize the degree of thermal expansion deformation of the CR.

As described above in detail, the exposure apparatus 100, and the first thereof in the present embodiment, the second exposure method, the second light IL ₂ as illumination light IL, the illumination light IL through a pattern RP1, first and second photosensitive layer RG1 through the projection optical system PL, RG2 is irradiated to each shot area on the wafer W which is provided, a first light IL ₁ as illumination light IL, the illumination through the pattern RP2 The light IL is irradiated to each shot region on the wafer W provided with the first and second photosensitive layers RG1 and RG2 via the projection optical system PL. Thereby, a latent image of the combined pattern (target pattern RP0) of the overlapping portions of the patterns RP1 and RP2 is formed on the resist layers RG1 and RG2, respectively. Therefore, a pattern exceeding the resolution limit (finer than the wavelength of illumination light) can be resolved on the wafer. Then, by developing the exposed wafer W, a resist image (resist pattern) of the pattern RP0 is formed in each shot area of the wafer W.

  Further, according to the exposure apparatus 100 of the present embodiment, high-throughput double exposure using a double reticle holder type reticle stage is possible. Further, by using a cutting reticle in which a plurality of cutting patterns are formed in a predetermined positional relationship as a main reticle, and using a masking reticle in which an opening pattern corresponding to the cutting pattern is formed as a masking reticle, cutting exposure is performed 1 With a single cutting reticle and a single masking reticle, a multiple exposure method can be used without any development process.

In the above-described embodiment, a purge cover having an opposing surface that faces at least one of the incident end and the emission end of the sub optical system 60 with respect to the corresponding reticle R1 or R2 via a predetermined clearance (3 mm or less). To form a substantially airtight space above the reticle, and the inside of this space may be purged with a purge gas such as dry air. Thereby, the haze of the reticle facing the purge cover can be reduced.
Further, at least a part of the facing surface facing the reticle R1 or R2 may be constituted by a temperature adjusting device for adjusting the temperature of the reticle.

In the above embodiment, the patterns RP1 and RP2 are individually transferred to the resist layers RG1 and RG2 on the wafer W. However, since the resist layers RG1 and RG2 have different photosensitive wavelengths (wavelength dependence), the patterns Depending on the size and the arrangement, it is possible to simultaneously transfer the resist layers RG1 and RG2 in the same shot region. For example, when transferring to each shot area on the wafer without overlapping two patterns, a reticle (with a pattern having a size about the resolution limit of the second light IL ₂ formed on the second reticle stage RST2 ( A switching device is loaded with a reticle (referred to as a fourth reticle for convenience) loaded with a pattern having a size that can be resolved with the first light IL ₁ on the first reticle stage RST1. first at 56, both the second light sources 52 and 54 connected to the illumination optical system IOP, using illumination light IL first light IL ₁ and the second a light IL ₂ simultaneously, the illumination region of the above Illuminating the IAR1, exposure similar to the second exposure method described above is performed. As a result, the pattern of the third reticle and the pattern of the fourth reticle can be resolved on each of the resist layers RG1 and RG2 on the wafer W.

However, in the exposure apparatus 100 described above, the method of using the first light IL ₁ and the second light IL ₂ at the same time transfers two shot patterns to each shot region on the wafer without overlapping them. Although it can be applied, when there are overlapping portions between two patterns, it may be impossible to apply depending on the size of both patterns. Next, a description will be given of a second embodiment in which exposure can be performed using the first light IL ₁ and the second light IL ₂ at the same time without any problem even if there is an overlapping portion between the two patterns. .

<< Second Embodiment >>
FIG. 6 schematically shows the arrangement of an exposure apparatus 100 ′ according to the second embodiment. The exposure apparatus 100 ′ includes a first illumination system IOP ₁ , a second illumination system IOP ₂ , a first reticle stage RST1, a second reticle stage RST2, a projection unit PU including a projection optical system PL, a wafer stage WST, and these A control system is provided.

The first illumination system IOP ₁ is configured in the same manner as the illumination system disclosed in, for example, US Patent Application Publication No. 2003/0025890, and light having a wavelength of 248 nm from a KrF excimer laser as a light source is used as illumination light IL _1. The slit-shaped illumination area IAR ₁ extending in the X-axis direction is illuminated with a uniform illuminance on the first reticle R1 placed on the first reticle stage RST1.

Second illumination system IOP ₂ has the same configuration as the first illumination system IOP _1, light of wavelength 193nm from an ArF excimer laser as a light source as illumination light IL _2, placed on the second reticle stage RST2 a slit-shaped illumination area IAR ₂ extending in the X-axis direction on the second reticle R2 illuminated with uniform illuminance.

The positions of the first and second reticle stages RST1 and RST2 are measured by the first and second reticle interferometers 14 ₁ and 14 ₂ via the movable mirrors 12 ₁ and 12 ₂ , respectively. It is supplied to the control device 120 (see FIG. 7). Based on the measurement results of reticle interferometers 14 ₁ and 14 ₂ , main controller 120 independently drives (positions) first and second reticle stages RST 1 and RST 2 via reticle stage drive systems 11 ₁ and 11 _2. Control.

The projection unit PU has a housing (lens barrel) 40 and a projection optical system PL composed of a plurality of optical members (lenses, mirrors, etc.) disposed in a predetermined positional relationship within the barrel 40. The projection optical system PL, for example, the same configuration as the projection optical system US is disclosed in Patent Application Publication No. 2007/0013885 Pat, the illumination light IL ₁ through the first reticle R1, the second reticle R2 The illuminated illumination light IL ₂ is synthesized on the same optical axis AXp and irradiated onto the wafer W. The projection optical system PL is, for example, a bilateral telecentric catadioptric system, and its projection magnification is 1/4 or 1/5. In addition, the projection optical system PL is suppressed to a level where there is chromatic aberration with respect to both the illumination lights IL ₁ and IL ₂ .

The projection optical system PL is provided with an image formation characteristic correction device 41 (see FIG. 7). The image formation characteristic correction device 41 connects the projection optical system PL to both the illumination lights IL ₁ and IL _2. Image characteristics (various aberrations) are corrected.

  Wafer stage WST is configured in the same manner as in the first embodiment, and is driven on stage base 22 with a predetermined stroke in the X-axis direction and Y-axis direction by stage drive system 24 (not shown in FIG. 6, see FIG. 7). At the same time, it is finely driven in the Z-axis direction, θx direction, θy direction, and θz direction.

  Position information of wafer stage WST in the XY plane (including rotation information (yaw amount (rotation amount θz in θz direction), pitching amount (rotation amount θx in θx direction), rolling amount (rotation amount θy in θy direction))) Is always detected by the interferometer system 18 through the movable mirror 16 (or the reflecting surface formed on the end surface of the wafer stage WST) with a resolution of, for example, about 0.25 nm. Measurement information of the interferometer system 18 is supplied to the main controller 120 (see FIG. 7). Main controller 120 controls the position (including rotation in the θz direction) of wafer stage WST in the XY plane via stage drive system 24 based on measurement information from interferometer system 18.

  In addition, the exposure apparatus 100 ′, like the exposure apparatus 100 of the first embodiment, has a total of four reticle alignments, each pair used for reticle alignment of the focus sensor AF, alignment system AS, and reticles R1 and R2. A system 13 (both not shown in FIG. 6, see FIG. 7) is provided.

  FIG. 7 is a block diagram showing the input / output relationship of the main controller 120 that mainly constitutes the control system of the exposure apparatus 100 ′ of the second embodiment. The main control device 120 includes a microcomputer (or workstation) and controls the entire device.

Prior to exposure, the reticle loader (not shown), as a first reticle R1, the reticle R2 ₂ described above is loaded on the first reticle stage RST1. At the same time, as the second reticle R2, the reticle R2 ₁ described above is loaded on the second reticle stage RST2. Further, a wafer loader (not shown) having a photosensitive layer (resist layers RG1 and RG2 (see FIG. 3F)) formed on the surface thereof by a coater / developer (not shown) provided in the exposure apparatus 100 ′. ) Is loaded onto a wafer holder (not shown) of wafer stage WST.

Thereafter, like the normal scanner, the main controller 120 uses the two pairs of reticle alignment systems 13, the reference mark plate (not shown) on the wafer stage WST, the alignment system AS, and the like to use the reticles R _{2 2} and R ₂ . ₁ reticle alignment, baseline measurement of the alignment system AS, and the like are performed. Subsequent to these preparation operations, the main controller 120 executes wafer alignment (alignment measurement) such as so-called multi-shot EGA within a shot.

  Based on the in-shot multipoint EGA, an array coordinate of shot areas on the wafer and a deformation amount (magnification, rotation, orthogonality) including the magnification of each shot area are obtained.

  Therefore, main controller 120 corrects the imaging characteristics (aberration) of projection optical system PL using imaging characteristics correction device 41. At this time, the main controller 120 takes into consideration the amount of deformation (magnification, rotation, orthogonality) including the magnification of each shot area obtained by the above-described multi-point EGA in the shot, and the like, and controls the imaging characteristic correction device 41. Using this, the aberration of the projection optical system PL is corrected.

Main controller 120 determines wafer stage WST as a wafer based on the alignment coordinates of the shot area on wafer W obtained by alignment measurement (multi-point EGA in a shot) and the baseline of alignment system AS previously measured. A stepping operation for moving to the scanning start position of each shot area on W, and the first and second reticle stages RST1, RST2 and wafer stage WST in the Y-axis direction at a speed ratio corresponding to the projection magnification of the projection optical system PL. The scanning exposure operation that moves synchronously is repeated. Thus, the image of the reticle R2 ₁ pattern under illumination light IL _2, and an image of the reticle R2 ₂ pattern under illumination light IL _1, in each shot area on the wafer W, is formed at the same time . Thereby, latent images of the patterns RP1 and RP2 of the reticles R2 ₁ and R2 ₂ are formed on the resist layers RG1 and RG2 in the same shot region, respectively, and the pattern RP0 is resolved on the wafer W as a combined pattern of both. The

As described above, according to the second embodiment, in addition to obtain a first exposure method same effect as in the first embodiment described above, the pattern of the reticle R2 ₁ under the illumination light IL ₂ an image of, since the exposure of the wafer W with the image of the reticle R2 ₂ pattern under illumination light IL ₁ can be performed simultaneously, as compared with the case of performing them separately and sequentially, improves throughput To do.

  In the first and second embodiments described above, the first and second photosensitive layers RG1 that expose the patterns RP1 and PR2 to each of the two types of illumination light using two types of illumination light having different wavelengths. , RG2 was transferred. However, the present invention is not limited to this, and three or more photosensitive layers that are respectively exposed to three or more types of illumination light having different wavelengths are formed on the wafer W, and three or more patterns are formed on the wafer using the three or more types of illumination light. It is also possible to transfer individually or simultaneously to three or more photosensitive layers on W. As a result, a finer pattern can be resolved on the wafer.

In each of the above embodiments, the positions of the first and second reticle stages RST1 and RST2 are measured by the first and _second reticle interferometers 14 ₁ and 14 ₂ , and the position of the wafer stage WST is determined by the interferometer system 18. The case of being measured is illustrated. However, the present invention is not limited to this, and an encoder (an encoder system composed of a plurality of encoders) may be used instead of or together with the first and second reticle interferometers 14 ₁ and 14 ₂ . Similarly, an encoder (an encoder system composed of a plurality of encoders) may be used instead of or together with the interferometer system 18.

  In each of the above embodiments, the case where the exposure apparatus is a dry type that exposes the wafer W without using liquid (water) has been described. However, the present invention is not limited to this. For example, International Publication No. 99/49504, As disclosed in European Patent Application Publication No. 1,420,298, International Publication No. 2004/055803, U.S. Patent No. 6,952,253, etc., between the projection optical system and the wafer. The above-described embodiments can also be applied to an exposure apparatus that forms an immersion space including an optical path of illumination light and exposes the wafer with illumination light through the projection optical system and the liquid in the immersion space. The above embodiments can also be applied to an immersion exposure apparatus disclosed in, for example, US Patent Application Publication No. 2008/0088843.

  In each of the above embodiments, the case where the exposure apparatus is a scanning exposure apparatus such as a step-and-scan method has been described. However, the present invention is not limited to this, and each of the above embodiments is applied to a stationary exposure apparatus such as a stepper. You may do it. In addition, as disclosed in, for example, US Pat. No. 6,590,634, US Pat. No. 5,969,441, US Pat. No. 6,208,407, a plurality of wafers. The above embodiments can also be applied to a multi-stage type exposure apparatus having a stage. Further, as disclosed in, for example, International Publication No. 2005/0774014, an exposure apparatus provided with a measurement stage including a measurement member (for example, a reference mark and / or a sensor) separately from the wafer stage is also described above. Each embodiment is applicable.

The light source is not limited to the ArF excimer laser, and pulses such as a KrF excimer laser (output wavelength 248 nm), F ₂ laser (output wavelength 157 nm), Ar ₂ laser (output wavelength 126 nm), Kr ₂ laser (output wavelength 146 nm), etc. It is also possible to use a laser light source, an ultrahigh pressure mercury lamp that emits bright lines such as g-line (wavelength 436 nm), i-line (wavelength 365 nm), and the like. A harmonic generator of a YAG laser or the like can also be used. In addition, as disclosed in, for example, US Pat. No. 7,023,610, a single wavelength laser beam in an infrared region or a visible region oscillated from a DFB semiconductor laser or a fiber laser is used as vacuum ultraviolet light. For example, a harmonic that is amplified by a fiber amplifier doped with erbium (or both erbium and ytterbium) and wavelength-converted into ultraviolet light using a nonlinear optical crystal may be used.

  Note that the object on which a pattern is to be formed (the object to be exposed to the energy beam) in each of the above embodiments is not limited to the wafer, but other objects such as a glass plate, a ceramic substrate, a film member, or a mask blank. But it ’s okay.

  The use of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, but for example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern to a square glass plate, an organic EL, a thin film magnetic head, an image sensor (CCD, etc.), micromachines, DNA chips and the like can also be widely applied to exposure apparatuses. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates or silicon wafers, etc. The embodiments described above can also be applied to an exposure apparatus that transfers a circuit pattern.

  An electronic device such as a semiconductor element includes a step of designing a function / performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and the exposure apparatus (pattern forming apparatus) of the above-described embodiment. And a lithography step for transferring the mask (reticle) pattern to the wafer by the exposure method, a development step for developing the exposed wafer, and an etching step for removing the exposed member other than the portion where the resist remains by etching, It is manufactured through a resist removal step for removing a resist that has become unnecessary after etching, a device assembly step (including a dicing process, a bonding process, and a packaging process), an inspection step, and the like. In this case, in the lithography step, the exposure method described above is executed using the exposure apparatus of each of the above embodiments, and a device pattern is formed on the wafer. Therefore, a highly integrated device can be manufactured with high productivity. .

  The exposure apparatus and exposure method of the present invention are suitable for forming a pattern on an object. The device manufacturing method of the present invention is suitable for manufacturing micro devices.

14 ₁ ... 1st reticle interferometer, 14 ₂ ... 2nd reticle interferometer, 41 ₁ , 41 ₂ ... Imaging characteristic correction device, 52 ... 1st light source, 54 ... 2nd light source, 56 ... Switching device, 60 ... Deputy optical system, 61 ... displacement measuring system, 100 ... exposure apparatus, 120 ... main control unit, BD ... body, IL ... illumination light, IL 1 _... first light, IL 2 _... second light, IOP ... illumination optical system , PL ... projection optical system, R1 ... first reticle, R2 ... second reticle, RST1 ... first reticle stage, RST2 ... second reticle stage, RB2 ... second reticle base, RB1 ... first reticle base, W ... wafer , WST ... Wafer stage.

Claims (21)

An exposure apparatus that exposes an object to form a pattern on the object,
A first mask having a first pattern disposed on the first surface and a first mask are switched or simultaneously switched between the first light of the first wavelength and the second light of the second wavelength different from the first wavelength, and the first mask A second mask having a second pattern arranged on two surfaces, which has at least a component capable of irradiating as illumination light and optimizing chromatic aberration with respect to the first and second lights, and An optical system capable of forming an image of a composite pattern composed of an overlapping portion of the pattern and the second pattern on the image plane;
A first holding member for holding the first mask;
A second holding member for holding the second mask;
An exposure apparatus comprising: a third holding member that holds the object.   The optical system irradiates the first light and the second light simultaneously to the first pattern and the second pattern, respectively, and the first light and the second light through the first pattern, respectively. The exposure apparatus according to claim 1, wherein the second light through two patterns is synthesized on the same optical axis and irradiated onto the object.   The optical system switches between the first light and the second light, and irradiates the first mask on which the first pattern is formed as the illumination light, and passes through the first mask. A first optical system that irradiates the second surface with illumination light and forms an image of the first pattern on the second mask disposed on the second surface, and the illumination through the second mask. 2. An exposure apparatus according to claim 1, further comprising: a second optical system that irradiates light onto the object and forms an image of a combined pattern obtained by superimposing the second pattern and the first pattern on the object. . It further comprises a base frame installed on the floor,
The exposure apparatus according to claim 3, wherein the first optical system is supported by the base frame in a vibration-proof manner in a suspended state.   The exposure apparatus according to claim 4, wherein the second holding member moves substantially along the second surface. A first base supported on the base frame by vibration isolation;
The exposure apparatus according to claim 5, wherein the second holding member moves on the first base. Two second masks can be placed on the second holding member side by side in a direction parallel to the first axis in a two-dimensional plane parallel to the second surface,
The exposure apparatus according to claim 5, wherein the second holding member moves at least in a direction parallel to the first axis.   The exposure apparatus according to claim 5, wherein the first holding member moves substantially along the first surface. A second base supported on the base frame in a vibration-proof manner;
The exposure apparatus according to claim 8, wherein the first holding member moves on the second base. A first position measurement system for measuring position information of the first holding member;
A second position measurement system for measuring position information of the second holding member;
A third position measurement system for measuring position information of the first optical system;
Based on the position information of the first, second, and third position measurement systems, at least one of the first and second holding members is controlled, and the first holding member, the second holding member, and the first The exposure apparatus according to claim 8, further comprising: a control system that servo-controls a positional relationship between the three optical systems.   The said optical system has a field stop arrange | positioned on the surface optically conjugate with respect to the image plane of the said 1st surface, the said 2nd surface, and the said 2nd optical system. The exposure apparatus according to item.   One of the first and second lights is light having the same wavelength as the ArF excimer laser light, and the other of the first and second lights is light having the same wavelength as the KrF excimer laser light. Item 12. The exposure apparatus according to any one of Items 1 to 11. An exposure apparatus according to any one of claims 1 to 12, wherein an object is exposed to form an image of a composite pattern composed of overlapping portions of the first pattern and the second pattern on the object. And
Developing the exposed object;
A device manufacturing method including: An exposure method for exposing an object to form a pattern on the object,
The first photosensitive layer having high sensitivity to the first light having the first wavelength and low sensitivity to the second light having the second wavelength different from the first wavelength and the first light having high sensitivity to the second light. Forming a second photosensitive layer having low sensitivity to the light on the object in a laminated state;
Illuminating the first pattern with the first light, irradiating the first light through the first pattern onto the object through a first optical system, exposing the first photosensitive layer, and Forming a first pattern latent image;
Illuminating the second pattern with the second light, irradiating illumination light through the second pattern onto the object via a second optical system including the first optical system, and the second photosensitive layer Exposing the second pattern to form a latent image of the second pattern;
An exposure method comprising:   The exposure method according to claim 14, wherein the latent image of the first pattern and the latent image of the second pattern are formed in a state in which one of them overlaps at least partially with respect to the other.   The exposure method according to claim 15, wherein an overlapping portion between the latent image of the first pattern and the latent image of the second pattern includes an image of a pattern having a size finer than a resolution limit of the first optical system. The first optical system and the second optical system are the same optical system,
The exposure method according to any one of claims 14 to 16, wherein forming the latent image of the first pattern and forming the latent image of the second pattern are performed before and after time. .   The exposure method according to any one of claims 14 to 16, wherein forming the latent image of the first pattern and forming the latent image of the second pattern are performed simultaneously. The second optical system includes a first optical system having a conjugate relationship between a second surface on which the first pattern is disposed and a surface of the object, and a second surface on which the second surface and the second pattern are disposed. A third optical system having a conjugate relationship with one surface,
The first light and the second light are simultaneously irradiated onto the object via the second pattern, the third optical system, the first pattern, and the first optical system sequentially. The exposure method according to claim 18.   One of the first and second lights is light having the same wavelength as the ArF excimer laser light, and the other of the first and second lights is light having the same wavelength as the KrF excimer laser light. Item 20. The exposure method according to any one of Items 14 to 19. Forming a pattern on the object by the exposure method according to any one of claims 14 to 20,
Developing the object with the pattern formed thereon;
A device manufacturing method including: