JP2007287760A - Illumination optical device, projection aligner, projection optical system and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform exposure with an optimum illumination condition on a whole face for respective patterns of a plurality of pattern regions which are closely arranged. <P>SOLUTION: An illumination optical system IU of a projection aligner which projects and exposes the pattern of a reticle R on a wafer W is provided with a secondary relay optical system 22 forming a face 62 which is optically conjugate with a reticle face between an exposure light source 10 and the reticle R and an optical path synthesis mirror 21 synthesizing exposure light beams IL1 and IL2 from the exposure light source 10 on the reticle face so that they are closely irradiated. The optical path synthesis mirror 21 comprises reflection faces 21a and 21b reflecting the exposure light beams IL1 and IL2. A ridgeline 21c of a boundary of the reflection faces 21a and 21b is arranged on a face 62 or near it. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an illumination technique and an exposure technique used for projecting a pattern of a first surface onto a second surface, and lithography for manufacturing various devices such as a semiconductor element, a liquid crystal display element, or a thin film magnetic head, for example. It is suitable for use in transferring a mask pattern onto a photosensitive substrate in the process.

  A double exposure method is one of exposure methods for transferring a reticle pattern as a mask onto a wafer (or glass plate or the like) coated with a resist, which is used when manufacturing a semiconductor element or the like. . This is because, for example, when a pattern in which a periodic pattern and an isolated pattern are mixed is exposed on the same layer on the wafer, the reticle pattern corresponds to the first pattern corresponding to the periodic pattern and the isolated pattern. The second pattern is divided into two patterns, and these two patterns are subjected to double exposure by sequentially optimizing the exposure conditions, thereby obtaining high imaging performance. Conventionally, when exposure is performed by such a double exposure method, a first exposure is performed using a first reticle in which one or a plurality of first patterns are formed, and then the reticle is subjected to the second exposure. The second exposure was performed by exchanging with a second reticle having one or a plurality of patterns. However, high throughput cannot be obtained by performing exposure by exchanging the reticle in this way.

Therefore, the first and second patterns are formed on one reticle, and the reticle pattern is transferred to the adjacent first and second shot areas on the wafer by a scanning exposure method. Is moved stepwise in the scanning direction by one shot area, and the pattern of the reticle is transferred to the second and third shot areas on the wafer, so that the first and second shot areas are transferred to the second shot area. An exposure method that double-exposes the above pattern has been proposed (for example, see Patent Document 1). In this exposure method, the illumination conditions for the two patterns can be optimized by changing the illumination conditions for illuminating the first and second patterns in a predetermined illumination area during scanning exposure.
JP-A-11-111601

  In the double exposure method combined with the conventional scanning exposure as described above, when only the first or second pattern is in the visual field of the projection optical system, the illumination conditions (illumination method, polarized illumination, etc.) are optimized. It can be carried out. However, when at least a part of the two patterns are in the field of view at the same time and at least a part of the two patterns are in the predetermined illumination area at the same time, the illumination condition is set for both patterns. It is difficult to set them individually. Therefore, it is difficult to optimize the illumination conditions over the entire surfaces of the first and second patterns.

Further, when the illumination conditions of the two patterns are greatly different, a certain amount of time is required to switch the illumination conditions in the illumination optical system, so that it is difficult to increase the reticle scanning speed, and throughput is reduced. There was also a problem that it was difficult to raise.
In view of such circumstances, the present invention, when transferring two adjacent patterns or patterns in two pattern areas onto a photosensitive substrate, optimally illuminates the entire surface of each pattern. It is a first object to provide an illumination technique and an exposure technique that can be illuminated with the above.

  Furthermore, the present invention can perform double exposure with high throughput, and can perform exposure under optimal illumination conditions on the entire surface for each pattern to be subjected to double exposure or for each pattern in each pattern region. A second object is to provide an optical technique, an exposure technique, and a device manufacturing technique.

  A first illumination optical apparatus according to the present invention is used in a projection exposure apparatus that projects and exposes a pattern arranged on a first surface onto a second surface, and illumination light from a light source (10) on the first surface. A third surface (62) disposed between the light source and the first surface and optically conjugate with the first surface between the light source and the first surface. The first optical flux (IL1) from the light source is different from the first optical flux disposed in the optical path between the relay optical system (22) to be formed and the light source and the first surface. And an optical path synthesizer (21) that synthesizes the light beam (IL2) so as to be closely irradiated on the first surface, and the optical path synthesizer includes a first region corresponding to the first light flux. (21a) is separated from the first region, and the second region (21b) corresponding to the second light flux Together comprise the boundary (21c) of the first region and its second regions are those located in the vicinity of the third side or third sides.

According to the present invention, the entire surface of each pattern can be illuminated under optimum illumination conditions by illuminating two patterns or patterns in two pattern regions with the first light flux and the second light flux, respectively.
A second illumination optical apparatus according to the present invention is used in a projection exposure apparatus that projects and exposes a pattern arranged on a first surface onto a second surface, and a light source (10) emits the first surface. In an illumination optical apparatus that supplies illumination light, a plurality of different light beams (IL1, IL2) from the light source that are arranged in an optical path between the light source and the first surface are brought close to each other on the first surface. The optical path synthesizer (21) that synthesizes the light so as to be irradiated is positioned on the third surface (62) optically conjugate with the first surface or in the vicinity of the third surface. A discontinuous point (21c) is provided, and the plurality of light beams pass through each of a plurality of regions (21a, 21b) partitioned by the discontinuous point.

According to the present invention, the entire surface of each pattern is optimized by illuminating two patterns, or patterns in two pattern areas, for example, with the first and second light beams among the plurality of light beams. Can be illuminated under various lighting conditions.
An exposure apparatus according to the present invention illuminates a pattern in a projection exposure apparatus that illuminates a pattern with illumination light and exposes the photosensitive substrate (W) through the pattern and the projection optical system (PL). Further, any one of the illumination optical devices (IU) of the present invention is provided.

  The device manufacturing method according to the present invention uses the projection exposure apparatus of the present invention. In this device manufacturing method, as an example, the pattern to be exposed has first and second pattern regions (RA, RB) arranged along the scanning direction, and the first and second pattern regions are included in the pattern. While illuminating with the first and second light beams, respectively, the patterns of the first and second pattern areas are respectively adjacent to the first and second partitioned areas (48A, 48A, 48A, 48) on the substrate in one scanning exposure. 48F).

In this case, since the pattern in the two pattern areas is transferred to the two partitioned areas on the photosensitive substrate by one scanning exposure, the substrate is stepped by one partitioned area in the next exposure. It is possible to perform double exposure with high throughput.
The projection optical system according to the present invention illuminates the first and second pattern regions (R1A, R1B) arranged along a predetermined scanning direction with the first and second light beams, respectively. The pattern having the first and second pattern areas is moved in the scanning direction in a state where the photosensitive substrate (W) is exposed with the first and second light fluxes that have passed through the second pattern area, respectively. The substrate is moved in a corresponding direction in synchronization with the first and second pattern regions adjacent to each other on the substrate by one scanning exposure. 48A, 48F) in a projection optical system (PL1) used for exposing the substrate with the first and second light fluxes that have passed through the first and second pattern regions, respectively. There, that 1 of those having an image shifter for shifting the relative position of the image formed by the image and its second beam formed by light beams (P1, P2).

  According to the present invention, in the projection exposure apparatus, the pattern in the two pattern areas is transferred to the two partitioned areas on the photosensitive substrate by one scanning exposure. By double-stepping the substrate by that amount, double exposure can be performed with high throughput. At this time, since there is an image shifter, the two pattern areas can be arranged apart from each other in the scanning direction, and the entire surface of the two pattern areas can be easily illuminated under optimum illumination conditions.

  In addition, although the reference numerals in parentheses attached to the predetermined elements of the present invention correspond to members in the drawings showing an embodiment of the present invention, each reference numeral of the present invention is provided for easy understanding of the present invention. The elements are merely illustrative, and the present invention is not limited to the configuration of the embodiment.

[First Embodiment]
A preferred first embodiment of the present invention will be described below with reference to FIGS. In this example, the present invention is applied to the case where exposure is performed using a scanning stepper type projection exposure apparatus which is a scanning exposure method.
FIG. 1 shows a projection exposure apparatus of this example. In FIG. 1, the projection exposure apparatus includes an exposure light source 10 and an illumination optical system IU that illuminates a reticle R as a mask with exposure light from the exposure light source 10. A reticle stage RST that holds and moves the reticle R, and a projection optical system PL that projects an image of a pattern in the illumination area of the reticle R onto a wafer W coated with a resist (photosensitive material) as a photosensitive substrate; , A wafer stage WST that holds and moves the wafer W, a drive mechanism such as these stages, and a main control system 36 comprising a computer that comprehensively controls the operation of these drive mechanisms and the like. An ArF excimer laser (wavelength 193 nm) is used as the exposure light source 10, but in addition, a KrF excimer laser (wavelength 248 nm), an F ₂ laser (wavelength 157 nm), a solid-state laser (YAG laser, semiconductor laser, etc.) A harmonic generator or a mercury lamp can also be used as the exposure light source.

Hereinafter, the Z-axis is taken in parallel to the optical axis AX9 of the projection optical system PL, and along the scanning direction of the reticle R and the wafer W during scanning exposure (a direction parallel to the paper surface of FIG. 1) in a plane perpendicular to the Z-axis. The Y axis is taken, and the X axis is taken along the non-scanning direction (direction perpendicular to the paper surface of FIG. 1) perpendicular to the scanning direction.
The exposure light (exposure illumination light) IL made up of linearly polarized ultraviolet pulsed laser light emitted from the exposure light source 10 passes through the beam matching unit (BMU) (not shown) along the optical axis AX1. And is divided into the first exposure light IL1 and the second exposure light IL2, and the first exposure light IL1 is reflected by the mirror 12 and enters the first illumination unit IUA having the optical axis AX2, and the second exposure light IL2 Enters the second illumination unit IUB having the optical axis AX4. In this example, a polarization beam splitter (PBS) is used as the light splitter 11, and the polarization direction of the exposure light IL incident on the light splitter 11 is the first exposure light IL 1 (P-polarized component) that passes through the light splitter 11. ) And the light amount of the second exposure light IL2 (S-polarized component) reflected by the light splitter 11 are set to be equal.

  Note that, for example, a half-wave plate (not shown) is rotatably provided on the exposure light source 10 side with respect to the light splitter 11 so that the polarization direction of the exposure light IL incident on the light splitter 11 can be changed, and the first The ratio between the light amount of the exposure light IL1 and the light amount of the second exposure light IL2 (S-polarized component) can be made variable. Alternatively, a half mirror can be used as the light splitter 11. This light splitter 11 can also be regarded as, for example, a multi-beam generator that branches a light beam from a light source into a plurality of light beams.

  The first exposure light IL1 incident on the first illumination unit IUA is a dimming unit (not shown) that controls the amount of light (illuminance) in a plurality of stages, a polarization controller 13A that controls the polarization state of the exposure light, and illumination optics. An optical integrator 16A through an exchangeable diffractive optical element (DOE) 14A for setting the light distribution of exposure light on the pupil plane of the system IU and a shaping optical system 15A for controlling the cross-sectional shape of the exposure light. Is incident on. The polarization control unit 13A includes, for example, a quarter wavelength plate and / or a half wavelength plate, and sets the polarization state of the emitted exposure light IL1 to linear polarization or circular polarization in a predetermined direction. Thus, the pattern of the reticle R can be illuminated with the first exposure light IL1 having a desired polarized illumination. The illumination intensity of the exposure light controlled by the dimming unit (not shown) and the polarized illumination set by the polarization controller 13A are each one of the illumination conditions of the exposure light.

  As an example, the diffractive optical element 14A can generate diffracted light so that the amount of light is distributed in the far field in the far field by the first exposure light IL1 incident thereon, thereby performing annular illumination. In addition to this, normal illumination, small σ illumination with a small coherence factor (σ value), dipole illumination in which the amount of light is large at two locations arranged so as to sandwich the optical axis on the pupil plane of the illumination optical system IU, and four locations Also, a diffractive optical element (not shown) for performing so-called modified illumination such as quadrupole illumination in which the amount of light increases is arranged in a state where it can be replaced with the diffractive optical element 14A. The main control system 36 can set a corresponding illumination system (annular illumination, dipole illumination, etc.) by installing a diffractive optical element selected from these diffractive optical elements on the optical path of the first exposure light IL1. . The illumination light quantity distribution on the pupil plane of the illumination optical system IU, which is the illumination system, and the exposure light incident angle distribution on the reticle R are also one of the illumination conditions.

  The shaping optical system 15A includes an afocal system, a pair of prisms (for example, a conical axicon system) disposed in the afocal system and movable at least one of them, a zoom lens system disposed after the afocal system, and exposure Consists of interchangeable polarization conversion elements, etc. for setting the distribution of the polarization state in the cross section of light to a predetermined distribution (such as a polarization characteristic distribution mainly composed of linearly polarized light in the circumferential direction on the pupil plane of the illumination optical system) Has been. The detailed configuration of the polarization control unit 13A, the diffractive optical element 14A, and the molding optical system 15A is described in, for example, International Publication No. 2004/051717, International Publication No. 2005/076045, International Publication No. 2005/050718. No. pamphlet etc. In this example, a fly-eye lens (or micro fly-eye lens) is used as the optical integrator 16A, but an internal reflection type integrator (rod integrator or the like), a diffractive optical element, or the like may be used instead.

  A part of the first exposure light IL1 that has passed through the optical integrator 16A is branched by a beam splitter (not shown), is incident on an integrator sensor (not shown) composed of a photoelectric detector, and the amount of light is measured. From the result, the integrated exposure amount at each point on the wafer W is indirectly monitored. The first exposure light IL1 that has passed through the beam splitter sequentially passes through the condenser optical system 17A to the fixed blind (fixed field (illumination field) stop) 31A and the movable blind (movable field (illumination field) diaphragm) 18A. As an example, the fixed blind 31A is installed on a surface slightly defocused from a surface optically conjugate with the pattern surface of the reticle R (hereinafter referred to as the reticle surface), and the movable blind 18A is optically conjugate with the reticle surface. It is installed on a flat surface. The fixed blind 31A is a field (illumination) stop that defines the shape of a slit-like illumination area elongated in the non-scanning direction on the reticle R, and the movable line 18A is other than a desired pattern area on the reticle R during scanning exposure. It is driven by the drive mechanism 32A to close the illumination area so that the first exposure light IL is not irradiated to the area. The operation of the drive mechanism 32A is controlled by a stage drive system 35 described later. The movable blind 18A is also used to control the width of the illumination area in the non-scanning direction.

A first illumination unit IUA is composed of the polarization controller 13A, the diffractive optical element 14A, the shaping optical system 15A, the optical integrator 16A, and the condenser optical system 17A. The first exposure light passes through the first illumination unit IUA. Reaches the fixed blind 31A and the movable blind 18A.
The first exposure light IL1 that has passed through the movable blind 18A is bent substantially at a right angle through the first primary relay optical system 19A and the optical path folding mirror 20A, travels along the optical axis AX3, and then passes through the optical path combining mirror 21. The light is reflected by the reflecting surface 21a and enters the secondary relay optical system 22 along the optical axis AX6. The optical path bending mirror 20A and the optical path combining mirror 21 are disposed between the primary relay optical system 19A and the position where the image of the opening of the movable blind 18A is formed. The secondary relay optical system 22 is an optical system that optically conjugates a predetermined surface 62 and a reticle surface. Hereinafter, the surface 62 is referred to as a reticle conjugate surface 62.

  The optical path combining mirror 21 is a right-angle prism type reflecting member having reflecting surfaces 21a and 21b orthogonal to each other, and is formed by the ridgeline formed by the reflecting surfaces 21a and 21b (the planes on which the reflecting surfaces are positioned intersect each other). The straight line 21c is generally positioned on the reticle conjugate surface 62. The allowable value of the positional deviation of the ridge line 21c from the reticle conjugate surface 62 will be described later.

  On the other hand, the second illumination unit IUB includes a polarization control unit 13B, a diffractive optical element 14B, etc. having the same configuration as the corresponding optical members in the first illumination unit IUA, a shaping optical system 15B, an optical integrator 16B, and a condenser optical system. 17B. The second exposure light IL2 incident on the second illumination unit IUB is incident on the fixed blind 31B and the movable blind 18B (driven by the drive mechanism 32B controlled by the stage drive system 35) in the same manner as the first exposure light IL1. . The second exposure light IL2 that has passed through the movable blind 18B travels along the optical axis AX5 through the second primary relay optical system 19B and the optical path bending mirror 20B, and is then reflected by the reflecting surface 21b of the optical path combining mirror 21. Then, the light enters the secondary relay optical system 22. Also in this case, the second primary relay optical system 19B forms an image of the opening of the movable blind 18B on the reticle conjugate surface 62. Since the polarization controller 13B and the diffractive optical element 14B in the second illumination unit IUB are controlled independently of the polarization controller 13A and the diffractive optical element 14A in the first illumination unit IUA, the second exposure is performed. The illuminance, illumination conditions, and polarization state of the light IL2 can be set independently of the first exposure light IL1.

  The optical path combining mirror 21 is disposed between the exposure light source 10 and the reticle surface, that is, in the present example, in the vicinity of the reticle conjugate surface 62 or the reticle conjugate surface 62, and the light flux from the first illumination unit IUA and the second light beam. It can be regarded as an optical path combiner that combines the light flux from the illumination unit IUB. The reflective surface 21a of the optical path combiner 21 can be regarded as the first region of the optical path combiner, and the reflective surface 21b can be regarded as the second region of the optical path combiner. The reticle conjugate surface 62 can be regarded as a third surface optically conjugate with the first surface on which the pattern surface of the reticle R is located.

With the above configuration, even if the plurality of movable blinds 18A and 18B are spatially separated, the images of the plurality of movable blinds 18A and 18B are positioned adjacently on the reticle conjugate surface 62. Can do.
The exposure lights IL1 and IL2 synthesized by the optical path synthesis mirror 21 are a secondary relay optical system including a lens system 22a, an optical path folding mirror 22b, a lens system 22c, a lens system 22d, an optical path folding mirror 22e, and a lens system 22f. 22 illuminates the pattern provided on the pattern surface (reticle surface) of the reticle R along the optical axes AX6, AX7, and AX8. The optical axis AX8 of the illumination optical system IU on the reticle R coincides with the optical axis AX9 of the projection optical system PL. The illumination units IUA and IUB, fixed blinds 31A and 31B, movable blinds 18A and 18B, primary relay optical systems 19A and 19B, optical path bending mirrors 20A and 20B, optical path combining mirror 21, and secondary relay optical system 22 are included. The illumination optical system IU is configured.

  FIG. 2 is a diagram schematically showing the illumination optical system IU in FIG. 1, and in FIG. 2 in which a plurality of optical path bending mirrors in the illumination optical system IU in FIG. 1 are omitted, the condensers of the illumination units IUA and IUB are shown. The illumination areas 23A and 23B (openings of the movable blinds 18A and 18B) formed by the exposure light from the optical systems 17A and 17B are decentered with respect to the primary relay optical systems 19A and 19B, which are subsequent optical systems. The technique disclosed in Japanese Patent Application Laid-Open No. 2000-21756 can be applied to the technique of forming the illumination areas 23A and 23B that are formed but eccentric with no light loss.

  These illumination areas 23A and 23B are adjacent to each other on the reticle conjugate surface 62 via the primary relay optical systems 19A and 19B, the optical path bending mirrors 20A and 20B, and the reflection surfaces 21a and 21b of the optical path combining mirror 21, respectively. Re-imaged as illuminated areas 24A and 24B. Then, the secondary relay optical system 22 re-images the illumination areas 24A and 24B adjacent to each other as the first illumination area 25A and the second illumination area 25B adjacent to each other on the reticle R. The widths of the openings of the movable blinds 18A and 18B in the direction corresponding to the scanning direction (Y direction) of the reticle R are respectively defined by the movable blinds 18A1 and 18A2 and the blinds 18B1 and 18B2. The width in the scanning direction of the illumination regions 25A and 15B on the reticle R can be controlled by the width in the direction corresponding to the scanning direction of the openings of the movable blinds 18A and 18B.

  FIG. 3 shows the first illumination field 18AP and the second illumination, which are images of the aperture PL when the field of view PLF of the projection optical system PL of the present example and the first and second movable blinds 18A and 18B are fully opened. FIG. 3 shows the relationship with the field 18BP. In FIG. 3, the first illumination field 18AP and the second illumination field 18BP are rectangular areas that are the same in size and elongated in the X direction (non-scanning direction). The first illumination field 18AP and the second illumination field 18BP pass through the optical axis AX8 on the emission side of the secondary relay optical system 22 (the optical axis AX9 of the projection optical system PL) and is a boundary line 18C parallel to the X axis. The two illumination fields 18AP and 18BP are generally inscribed in the outline of the field of view PLF of the projection optical system PL as a whole. The boundary line 18C is also an image of the ridge line 21c of the optical path combining mirror 21 in FIG. 2 by the secondary relay optical system 22. Further, the illumination fields 18AP and 18BP are equal to the areas when the illumination areas 25A and 25B are maximized. In this example, the movable blinds 18A and 18B are in a direction corresponding to the scanning direction during scanning exposure as described later. By opening and closing the illumination area, the widths of the illumination areas 25A and 25B in the scanning direction are controlled in the illumination fields 18AP and 18BP, respectively, according to the position of the reticle R in the scanning direction.

  Returning to FIG. 1, under the exposure light IL1 and IL2, the pattern in the illumination area of the reticle R is projected at a predetermined projection magnification β (β is 1/4, 1/5, etc.) via the projection optical system PL. It is projected onto an exposure area on the wafer W coated with a resist. That is, the projection optical system PL projects (projects exposure) a pattern on the reticle surface that is the object plane onto the surface of the wafer W that is the image plane. The wafer W is a disk-shaped substrate having a diameter of 200 mm or 300 mm, for example. As the projection optical system PL, in addition to the refractive system, for example, as disclosed in Japanese Patent Application Laid-Open No. 2001-249286, an optical system having an optical axis from the reticle to the wafer, and substantially orthogonal to the optical axis. And a catadioptric projection optical system that forms an intermediate image twice inside.

  The reticle R is attracted and held on a reticle stage RST, and the reticle stage RST is placed on a reticle base (not shown) so as to be continuously moved in the Y direction by a linear motor or the like. Further, the reticle stage RST incorporates a mechanism for finely moving the reticle R in the X direction, the Y direction, and the rotation direction around the Z axis. The position of the reticle stage RST (reticle R) is measured with high accuracy by the moving mirror 33R on the reticle stage RST and the laser interferometer 34R disposed opposite thereto, and the measurement result and control from the main control system 36 are performed. Based on the information, the stage drive system 35 controls the operation of the reticle stage RST. The stage drive system 35 opens and closes the movable blinds 18A and 18B via the drive mechanisms 32A and 32B based on position information in the Y direction (scanning direction) of the reticle stage RST (and thus the reticle R), that is, FIG. The width of each of the illumination areas 25A and 25B in the Y direction is controlled. The opening / closing operation of the movable blinds 32A and 32B may be controlled by a control device provided independently of the stage drive system 35.

  On the other hand, wafer W is sucked and held on wafer stage WST via wafer holder WH. Wafer stage WST is driven by a Z tilt stage that controls the focus position (position in the Z direction) and tilt angle of wafer W, a linear motor, and the like. It comprises an XY stage that continuously moves in the Y direction on a wafer base (not shown) and moves stepwise in the X and Y directions. The position of the wafer holder WH (wafer W) is measured with high accuracy by the moving mirror 33W on the wafer holder WH and the laser interferometer 34W arranged opposite thereto, and the measurement result and control information from the main control system 36 are used. Based on this, stage drive system 35 controls the operation of wafer stage WST. Note that the image surface on which the reticle pattern image formed by the projection optical system PL is formed can be regarded as the second surface, and the surface of the wafer W is positioned on the second surface.

  During the scanning exposure of the projection exposure apparatus of this example, the wafer W is exposed to the exposure area via the wafer stage WST in synchronization with the movement of the reticle R in the Y direction with respect to the illumination area at the speed VR via the reticle stage RST. The pattern image in a series of two pattern areas (details will be described later) of the reticle R is moved onto the wafer W by moving at a speed β · VR (β is the projection magnification from the reticle R onto the wafer W) in the Y direction. Are sequentially transferred to the shot areas adjacent in the two scanning directions. Although the projection optical system PL of this example forms an inverted image, the scanning direction of the reticle R and the wafer W is opposite, but when the projection optical system PL projects an erect image in the scanning direction, the reticle The scanning directions of R and wafer W are the same. Thereafter, the wafer stage WST is moved stepwise to move the next shot area on the wafer to the scanning start position, and scanning exposure is repeated by the step-and-scan method, and the scanning direction on the wafer W is repeated. The exposure is sequentially performed for every two shot areas adjacent to.

  If this exposure is a superposition exposure, it is necessary to align the reticle R and the wafer W in advance. Therefore, an alignment sensor (not shown) for detecting the position of the alignment mark attached to each shot area on the wafer W is installed on the side surface of the projection optical system PL. In addition, in order to measure the position of the alignment mark on the reticle R, a pair of image processing type alignment microscopes (not shown) is installed above the reticle stage RST.

Hereinafter, an example of the exposure operation of the projection exposure apparatus of this example will be described. Since two pattern regions (transfer patterns) for double exposure are formed along the scanning direction on the pattern surface of the reticle R in this example, the following description will be made assuming that double exposure is performed. .
FIG. 4A is a plan view showing the pattern arrangement of the reticle R used in this example. In FIG. 4A, the region surrounded by the rectangular frame-shaped light shielding band 51 of the reticle R is shown. The first and second pattern areas RA and RB having the same size are divided in the Y direction by the boundary light-shielding band 53, and different transfer patterns (hereinafter referred to as patterns respectively) in the pattern areas RA and RB. (Referred to as A and B) are drawn. The patterns A and B are patterns generated from a circuit pattern transferred to one layer of each shot area on the wafer W, and correspond to the circuit patterns by overlappingly exposing the images of the patterns A and B. A projected image is exposed in each shot area. As an example, the pattern A includes a Y-direction line-and-space pattern (hereinafter referred to as an L & S pattern) 55Y arranged in the Y-direction with a pitch of the resolution limit, and the pattern B is resolved in the X-direction. It consists of an L & S pattern 55X in the X direction arranged at a limit pitch.

  In the present example, the pattern B in the second pattern area RB and the pattern A in the first pattern area RA are illuminated by the first illumination area 25A and the second illumination area 25B in FIG. In the first illumination unit IUA in FIG. 1, a diffractive optical element for dipole illumination (with two secondary light sources separated in a direction corresponding to the X direction) for the X direction L & S pattern 55X is selected. In the second illumination unit IUB, the Y-axis diffractive optical element for the Y-axis L & S pattern 55Y (having two secondary light sources separated in the direction corresponding to the Y direction) is selected. In this case, the illumination areas 25A and 25B are illuminated with dipole illumination orthogonal to each other. For example, when the pattern B is a periodic pattern and the pattern A is an isolated pattern, as an example, the illumination method of the first illumination region 25A is set as the annular illumination, and the illumination method of the second illumination region 25B is changed. Small σ illumination may be used.

Also, the size of the pattern areas RA and RB of the reticle R in FIG. 4A corresponds to the size of one shot area on the wafer W, and the light shielding band 53 at the boundary between the pattern areas RA and RB. Has a width corresponding to the width of the street line between adjacent shot areas on the wafer W. That is, an image obtained by reducing the two pattern areas RA and RB with the projection magnification of the projection optical system PL corresponds to the size of two shot areas adjacent in the scanning direction on the wafer W.
Here, the street line refers to a linear non-device region arranged at each boundary portion of a plurality of semiconductor devices formed on a wafer, and the width is currently about 100 μm. When the width of the street line on the wafer W is 100 μm and the magnification of the projection optical system PL is ¼, the width of the light shielding band 53 is 400 μm. Therefore, it is necessary to make the boundary between the first illumination area 25A and the second illumination area 25B exactly coincide with the pattern areas RA and RB with a positional accuracy within 400 μm.

  For this purpose, positioning errors of the edge portions of the movable blinds 18A and 18B in FIG. 1 and distortions of the primary relay optical systems 19A and 19B and the secondary relay optical system 22 that relay the movable blinds 18A and 18B and the reticle pattern surface are performed. And the amount of deviation of the ridge line 21c of the optical path combining mirror 21 from the reticle conjugate surface 62 must be suppressed to a predetermined value or less. This is because if the ridge line 21c deviates from the reticle conjugate plane 62, the image on the reticle pattern plane is blurred due to defocusing, and the boundary between the first illumination area 25A and the second illumination area 25B is blurred.

Therefore, the amount of deviation of the ridgeline 21c of the optical path combining mirror 21 from the reticle conjugate surface 62 is less than the amount of deviation such that the blur width at the boundary between the first illumination region 25A and the second illumination region 25B is, for example, 400 μm or less. It is preferable.
If the positioning error of the movable blinds 18A and 18B and the distortion of the relay optical system are taken into consideration, it is preferable that the amount of deviation of the ridge line 21c from the reticle conjugate surface 62 is even smaller.
The allowable value of the deviation amount is the same in other embodiments and modifications described later.

Further, a pair of alignment marks 54A and 54B are formed so as to sandwich the pattern area of the reticle R in the X direction, and by measuring the positions of these alignment marks 54A and 54B with an alignment microscope (not shown), The reticle R can be aligned.
FIG. 8 shows a shot arrangement on the wafer W in this example. In FIG. 8, a large number of shot areas (typically represented by shot areas 48) are arranged on the wafer W at a predetermined pitch in the X direction and Y direction. These shot areas 48 are rectangular areas having a width F in the Y direction (scanning direction) and a width E in the X direction, including the area up to the center of the street line at the boundary with the adjacent shot areas. . In each of these shot areas 48, the image of the pattern A in the first pattern area RA and the image of the pattern B in the second pattern area RB of the reticle R in FIG. For example, two alignment marks 46A and 46B are attached to the shot area 48, and the coordinates of the alignment marks 46A and 46B in a predetermined number of shot areas 48 selected from the wafer W are used as wafer alignment sensors (not shown). ) And performing statistical processing, for example, each shot area on the wafer W can be aligned by the enhanced global alignment method.

  Next, FIG. 4 to FIG. 4 show operations when double exposure is performed on images of the two pattern areas RA and RB of the reticle R of FIG. 4A on the wafer W in the shot arrangement shown in FIG. 7 will be described with reference to FIG. 4A to 4L are views showing the positional relationship between the plurality of pattern areas RA and RB of the reticle R and the two illumination areas 25A and 25B, respectively, at the time of scanning exposure. Actually, the reticle R is scanned in the ± Y direction with respect to the illumination areas 25A and 25B. For convenience of explanation, however, the illumination area 25A is relatively moved on the reticle R in FIGS. 25B are shown moving in the Y direction.

  FIGS. 5A to 5D show the opening of the movable blind 18A (controlled by the blinds 18A1 and 18A2) and the opening of the movable blind 18B (blind 18B1) in the cases of FIGS. 4A to 4D, respectively. 6 (e) to (h) show the states of the openings of the movable blinds 18A and 18B in the case of FIGS. 4 (e) to (h), respectively. 7 (i) to (l) show the states of the openings of the movable blinds 18A and 18B in the cases of FIGS. 4 (i) to (l), respectively.

[First step]
First, two shot areas 48A and 48F adjacent to each other in the Y direction on the wafer W in FIG. 8 are scanned once, and the pattern B image B1 and the pattern area of the pattern area RB of the reticle R in FIG. The image A1 of the RA pattern A is exposed. As described above, the patterns A and B on the reticle R in FIG. 4A and the image A1 of the pattern A and the image B1 of the pattern B on the wafer W in FIG. This is because the projection optical system PL forms an inverted image. Further, in a state where the illumination areas 25A and 25B are both closed as shown in FIG. 4A, both the movable blinds 18A and 18B are closed as shown in FIG. 5A.

  Then, from the state of FIG. 4A, scanning of the reticle R in the + Y direction with respect to the illumination fields 18AP and 18BP in the field of view of the projection optical system PL of FIG. 3 is started. In synchronization with this, the wafer W in FIG. 8 is scanned in the −Y direction with respect to the exposure area of the projection optical system PL (area optically conjugate with the illumination areas 25A and 25B). In FIG. 8, the relative locus 47A of the exposure area with respect to the reticle R is represented by a dotted line. At this time, the wafer W is driven in synchronization so that the shot areas 48F and 48A on the wafer W overlap the images of the pattern areas RA and RB on the reticle R, respectively. At the time of scanning exposure, in FIG. 2, according to the position of reticle R in the Y direction, illumination areas 25A and 25B are within illumination fields 18AP and 18BP, respectively, and pattern areas surrounded by light shielding bands 51 and 53 of reticle R, respectively. Opening / closing control of the openings of the movable blinds 18A and 18B is performed so that only the patterns in the RB and RA (see FIG. 4A) are illuminated.

  First, when the pattern area RA of the reticle R enters the illumination field 18BP of FIG. 3, the second illumination area 25B begins to open as shown in FIG. 4B (movable blinds in the corresponding FIG. 5B). 18B starts to open), the second illumination area 25B is fully opened in FIG. 4C (the movable blind 18B is fully opened in the corresponding FIG. 5C), and only the pattern area RA is shown in FIG. In the state of passing through the field 18BP, the reticle R is scanned with respect to the second illumination region 25B as shown in FIGS. 4D and 4E (corresponding FIGS. 5D and 6D). In e), only the movable blind 18B is fully open). As a result, only the pattern image A1 of the first pattern area RA of the reticle R is sequentially exposed to the shot area 48F of the wafer W in FIG.

[Second step]
Next, as shown in FIG. 4 (f), when the pattern region RA of the reticle R is illuminated by the second illumination region 25B, the pattern region RB enters the illumination field 18AP of FIG. One illumination area 25A begins to open (the movable blind 18A begins to open in the corresponding FIG. 6 (f)), and the first illumination area 25A is fully opened in FIG. 4 (g) (movable in the corresponding FIG. 6 (g)). Blind 18A is fully open). In this state, both the illumination areas 25A and 25B are fully open, and there is a light shielding band 53 at the boundary between them. The pattern area RA of the reticle R is parallel to the adjacent shot areas 48F and 48A on the wafer W in FIG. And RB pattern images A1 and B1 are partially exposed. Thereafter, when the reticle R is further scanned in the + Y direction, the second illumination area 25B gradually closes following the light shielding band 53 as shown in FIG. 4H (movable in the corresponding FIG. 6H). The blind 18B is gradually closed), the second illumination area 25B is completely closed in FIG. 4 (i), and only the second pattern area RB of the reticle R is illuminated by the first illumination area 25A (FIG. In the corresponding FIG. 7 (i), the movable blind 18B is completely closed). As a result, the exposure to the shot area 48F on the wafer W in FIG. 8 is completed, and the exposure of only the adjacent shot area 48A is continued.

[Third step]
Next, in this state, the second pattern region RB of the reticle R is within the illumination field 18AP of FIG. 3, and the first pattern region RA is out of the illumination field 18BP, so FIG. 4 (j) and FIG. 4 (k), only the second pattern area RB of the reticle R is illuminated by the fully opened first illumination area 25A (corresponding to FIG. 7 (j), in FIG. 7 (k), only the movable blind 18A is illuminated. The image B1 of the pattern of the second pattern region RB is sequentially exposed to the shot region 48A of the wafer W in FIG. Thereafter, as shown in FIG. 4 (l), when the light shielding band 51 of the reticle R reaches the first illumination area 25A, the width of the first illumination area 25A gradually becomes 0 (in the corresponding FIG. 7 (l), the movable blind). 18A gradually closes), the exposure of the image B1 to the shot area 48A in FIG. 8 is also terminated. In this way, by exposing the reticle R having the two pattern areas RA and RB to the illumination areas 25A and 25B in the Y direction only once to perform exposure, two adjacent shot areas 48A and 48A on the wafer W are exposed. A pattern image is exposed to 48F. At this time, exposure to the shot areas 48A and 48F is performed by bipolar illumination in directions orthogonal to each other.

[Fourth step]
Next, following the state shown in FIG. 4L, the reticle R is moved to the scanning start position in the + Y direction with respect to the illumination fields 18AP and 18BP in FIG. 3, and in FIG. After the step movement of the two shot areas 48 by the width E in the X direction, the wafer W is moved in the + Y direction in synchronization with the movement of the reticle R in the -Y direction, and the illumination areas 25A and 25B are moved in FIG. ) To FIG. 4A, the pattern images B1 and A1 of the pattern areas RB and RA of the reticle R are respectively transferred to the shot areas 48B and 48G adjacent to the Y direction on the wafer W in FIG. Exposed. Thereafter, the reticle R is alternately scanned in the + Y direction and the Y direction, and the wafer W is driven synchronously so that the exposure area relatively moves along the locus 47A of FIG. Opening / closing the illumination areas 25A, 25B as shown in (l) exposes the image B1 to the series of shot areas 48A to 48E in the X direction on the wafer W in FIG. The image A1 is exposed to 48F to 48J.

[Fifth step]
Next, after the wafer W in FIG. 8 is stepped in the −Y direction by the width F in the Y direction of one shot region 48, the shot regions 48J and 48O adjacent to the Y direction on the wafer W in FIG. By performing the first to third steps described above (the scanning direction is the reverse direction), the pattern of the reticle R shown in FIG. 4A in each of the shot regions 48J and 48O by one scanning exposure. The pattern images B2 and A2 in the regions RB and RA are exposed. As a result, the pattern image B2 of the second pattern region RB of the reticle R and the image A1 of the pattern of the first pattern region RA are double-exposed on the shot region 48J.

  Thereafter, similarly to the fourth step, the reticle R is alternately scanned in the + Y direction and the −Y direction, and the wafer W is synchronized so that the exposure area relatively moves along the locus 47B of FIG. 4A to 4L, the illumination areas 25A and 25B are opened and closed, so that the image B2 is formed in a series of shot areas 48J to 48F in the X direction on the wafer W in FIG. The image A2 is exposed to a series of shot regions 48O to 48K in the third row in the X direction. The series of shot areas 48F to 48J in the second row in the X direction are double-exposed with the image A1 and the image B2, respectively.

[Sixth step]
Next, after the wafer W in FIG. 9 is stepped in the −Y direction by the width F in the Y direction of one shot region 48 (see FIG. 8), the reticle R is alternately scanned in the + Y direction and the −Y direction. Then, the wafer W is driven synchronously so that the exposure area relatively moves along the locus 47C of FIG. 10, and the illumination areas 25A and 25B are opened and closed as shown in FIGS. As a result, the series of shot areas 48K to 48O in the X direction on the wafer W in FIG. 10 is exposed to the pattern image B3 of the second pattern area RB of the reticle R, and a series of shot areas 48P to 48T in the X direction. Then, the pattern image A3 of the first pattern area RA is exposed. As a result, a series of shot areas 48K to 48T in the third row in the X direction are subjected to double exposure with the image A2 and the image B3, respectively.

By repeating this operation, the pattern image of the first pattern area RA of the reticle R and the pattern of the second pattern area RB are formed on all the shot areas except the shot area at the end in the ± Y direction on the wafer W. Are double-exposed. Thereby, the operation of the sixth step is completed.
At this time, since two shot areas adjacent to each other in the scanning direction on the wafer W are exposed by one scan, double exposure can be performed with extremely high throughput. Note that it is necessary to separately expose only the pattern area RA or RB pattern image of the reticle R to the shot area at the end in the Y direction on the wafer W, but the number of shot areas on the wafer W is as follows. Actually, it is much more than the arrangement of FIG.

  As described above, according to the present example, the movable blinds 18A and 18B are arranged to adjust the widths of the plurality of illumination areas 25A and 25B in the scanning direction so that the illumination areas 25B and 25A are accommodated in the pattern areas RA and RB. The illumination areas 25A and 25B can be positioned adjacent to each other in the scanning direction while being independently controlled in synchronization with the position of the reticle R in the scanning direction. Thereby, exposure light under different illumination conditions (illumination method, polarized illumination, illuminance, etc.) can be supplied to the entire surface of the plurality of pattern areas RA, RB along the scanning direction on the reticle R. Accordingly, since the entire surface of the plurality of pattern areas on the reticle R can be illuminated under optimized illumination conditions, high imaging characteristics (resolution, etc.) can be obtained for the projected image after double exposure. Therefore, the line width controllability of the circuit pattern finally formed is very good, and a semiconductor device or the like can be manufactured with high accuracy.

The configuration, operation, and the like of the projection exposure apparatus of this embodiment are summarized as follows.
A1) The illumination optical system IU in FIG. 1 is disposed between the exposure light source 10 and the reticle surface (pattern surface of the reticle R), and optically conjugate with the reticle surface between the exposure light source 10 and the reticle surface. The secondary relay optical system 22 that forms the reticle conjugate surface 62, and the exposure light source 10 and the reticle surface thereof are arranged between the exposure light source 10 and the first exposure light IL1 and the second exposure light IL2, respectively. And an optical path combining mirror 21 for combining so as to irradiate closely on the reticle surface. The optical path combining mirror 21 is separated from the first reflecting surface 21a that reflects the first exposure light IL1 and the reflecting surface 21a. And includes a second reflecting surface 21 b that reflects the second exposure light IL 2, and a ridge line 21 c at the boundary between the reflecting surfaces 21 a and 21 b is disposed on the reticle conjugate surface 62. The ridge line 21c only needs to be arranged in the vicinity of the reticle conjugate surface 62 as described above. Further, the projection exposure apparatus of this example includes the illumination optical system IU.

  As a result, the illumination areas of the exposure lights IL1 and IL2 are clearly separated on the reticle surface by the image of the ridge line 21c of the optical path combining mirror 21. Therefore, it becomes possible to individually illuminate two adjacent pattern areas RA and RB of the reticle R on the reticle surface with the exposure lights IL1 and IL2, and to optimize the illumination conditions of the exposure lights IL1 and IL2 independently. Thus, the entire surface of each pattern area RA, RB can be illuminated under optimum illumination conditions.

A2) The exposure light source 10 of FIG. 1 of this example is one, and includes an optical splitter 11 that branches the exposure light IL from the exposure light source 10 into two exposure lights IL1 and IL2. Therefore, it is only necessary to use one exposure light source, and the manufacturing cost of the projection exposure apparatus can be suppressed.
A3) The exposure light beams IL1 and IL2 may be guided from different exposure light sources without using the light splitter 11 of FIG. In this case, for example, energy control for each pulse can be performed for each of the exposure lights IL1 and IL2, and the range of types of illumination conditions that can be controlled independently for each pattern region can be expanded.

A4) Since the surfaces on which the exposure light beams IL1 and IL2 are incident on the optical path combining mirror 21 in FIG. 1 are the reflection surfaces 21a and 21b, respectively, the optical systems (illumination units IUA, IUB, etc.) for the exposure light beams IL1 and IL2 are symmetrical. Can be arranged. Therefore, it is easy to design and adjust the illumination optical system IU.
A5) However, as shown in a modification example described later, instead of the optical path combining mirror 21, it is also possible to use an optical path combining member that reflects only one of the exposure lights IL1 and IL2 and passes the other as it is.

A6) Further, as shown in a modification example described later, instead of the optical path combining mirror 21, it is also possible to use an optical path combining member having a refractive surface as a surface through which at least one of the exposure light beams IL1 and IL2 passes. In particular, when both are refracting surfaces, the optical systems for the exposure light IL1 and IL2 can be arranged symmetrically.
Further, instead of the optical path combining mirror 21, it is possible to use an optical path combining member having a surface through which at least one of the exposure light beams IL1 and IL2 passes, which is a combination of a reflective surface and a refractive surface.

  A7) Further, the illumination optical system IU of FIG. 1 includes a first movable blind 18A positioned in the optical path of the first exposure light IL1 and a second movable blind positioned in the optical path of the second exposure light IL2. 18B, by controlling the movable blinds 18A and 18B, the illumination areas by the first exposure light IL1 and the second exposure light IL2 on the reticle surface can be easily set with high accuracy independently of each other.

  A8) Also, the illumination optical system IU in FIG. 1 includes a first primary relay optical system 19A disposed in the optical path between the first movable blind 18A and the reticle conjugate surface 62, and a second movable blind. And a second primary relay optical system 19B disposed in the optical path between 18B and the reticle conjugate surface 62. Accordingly, since the images (illumination areas) of the openings of the movable blinds 18A and 18B can be easily placed close to each other on the reticle conjugate surface 62, the pattern areas RA and RB placed close to the reticle R are arranged. The pattern inside can be illuminated under different lighting conditions.

  A9) Also, the illumination optical system IU of FIG. 1 includes first and second illumination units IUA and IUB for supplying exposure light IL1 and IL2 to the first and second movable blinds 18A and 18B, respectively. The unit IUA and the first primary relay optical system 19A are arranged on the same axis, and the second illumination unit IUB and the second primary relay optical system 19B are arranged on the same axis. Easy.

A10) However, as shown in a modification example described later, the first illumination unit IUA and the first primary relay optical system 19A are arranged non-coaxially, and the second illumination unit IUB and the second primary relay optical are arranged. It is also possible to arrange the system 19B non-coaxially.
A11) Also, from another point of view, the illumination optical system IU of FIG. 1 of the present embodiment is disposed between the exposure light source 10 and the reticle surface, and a plurality of different exposure lights IL1 from the exposure light source 10 are provided. The optical path synthesis mirror 21 is configured to synthesize the IL2 so as to be irradiated close to each other on the reticle surface. The optical path synthesis mirror 21 is positioned on the reticle conjugate surface 62 or in the vicinity thereof so that the two reflection surfaces 21a and 21b are discontinuous. The plurality of exposure lights IL1 and IL2 respectively pass through the plurality of reflection surfaces 21a and 21b defined by the ridge line 21c. Further, the projection exposure apparatus of this example includes the illumination optical system IU.

As a result, the illumination areas of the exposure lights IL1 and IL2 are clearly separated on the reticle surface by the image of the ridge line 21c of the optical path combining mirror 21. Therefore, it becomes possible to individually illuminate two adjacent pattern areas RA and RB of the reticle R on the reticle surface with the exposure lights IL1 and IL2, and to optimize the illumination conditions of the exposure lights IL1 and IL2 independently. Can do.
A12) Further, the ridge line 21c of the optical path combining mirror 21 is a straight line, and the image on the reticle surface of the ridge line 21c is also a straight line, and each of the plurality of pattern areas partitioned by the straight line on the reticle surface is illuminated under optimum illumination conditions. it can.

[First Modification of First Embodiment]
FIG. 11 shows a main part of an illumination optical system according to a first modification of the first embodiment. In FIG. 11, in which parts corresponding to those in FIG. 1 and FIG. The difference from the first embodiment is that the optical axes AX2a and AX4a of the illumination units IUA and IUB that supply the exposure light to the movable blinds 18A and 18B, respectively, are the openings when the corresponding movable blinds 18A and 18B are fully opened ( It is a point positioned so as to be the center of the illumination areas 23A and 23B). In other words, in this modification, the optical axes AX2b and AX4b of the primary relay optical systems 19A and 19B and the optical axes AX2a and AX4a of the illumination units IUA and IUB are not coaxial with each other, but correspond to the scanning direction of the reticle R. It is shifted to. With this configuration, as the illumination units IUA and IUB, illumination units similar to those in which a conventional movable blind is used as a whole in one illumination optical system can be used.

[Second Modification of First Embodiment]
FIG. 12 shows a main part of an illumination optical system according to a second modification of the first embodiment. In FIG. 12, in which parts corresponding to those in FIG. 1 and FIG. The difference from the first embodiment is that an optical path combiner 26 composed of a mirror having one reflecting surface is provided instead of the optical path combining mirror 21 having two reflecting surfaces 21a and 21b orthogonal to each other in FIG. It is. Here, the optical path combiner 26 has a reflecting surface that is inclined so as to be 45 ° with respect to the optical axis AX5 of the second primary relay optical system 19B, and the light flux from the primary relay optical system 19B. Is deflected by 90 ° and guided to the secondary relay optical system 22. On the other hand, the light beam from the first primary relay optical system 19 </ b> A travels straight along the optical path outside the effective area of the optical path combiner 26 and travels toward the secondary relay optical system 22. Here, the side edge 26a of the reflection surface of the optical path combiner 26 has an optical axis AX2 of the primary relay optical system 19A, an optical axis AX5 of the primary relay optical system 19B, and an optical axis AX6 of the secondary relay optical system 22. Positioned on the intersecting point. The intersection is located on a surface optically conjugate with the reticle surface (pattern surface of the reticle R) with respect to the secondary relay optical system 22. In this modification, the configuration of the optical path combiner 26 is simple.

[Third Modification of First Embodiment]
FIG. 13 shows a main part of an illumination optical system according to a third modification of the first embodiment. In FIG. 13, in which parts corresponding to those in FIG. 12 are given the same reference numerals, this modification is shown in FIG. Instead of the optical path combiner 26 shown in the second modification, an optical path combiner 27 made of a trapezoidal light-transmitting prism member having a reflecting surface in part is provided. The optical path combiner 27 includes an incident surface 27A1 on which the light beam from the primary relay optical system 19A is incident, an exit surface 27A2 on which the light beam is emitted via the incident surface 27A1, and a light beam from the primary relay optical system 19B. And a reflecting surface 27B for deflecting the light beam by 90 °. Here, the entrance surface 27A1 and the exit surface 27A2 are provided so as to be parallel to each other, and the reflection surface 27B is obliquely provided at 45 ° with respect to the optical axis AX5 of the primary relay optical system 19B. . Also in the optical path combiner 27 of this modification, the end of the reflecting surface 27B is located on a surface optically conjugate with the reticle surface with respect to the secondary relay optical system 22. The exit surface 27A2 of the optical path combiner 27 is also located on a surface optically conjugate with the reticle surface with respect to the secondary relay optical system 22.

[Fourth Modification of First Embodiment]
FIG. 14 shows a main part of an illumination optical system according to a fourth modification of the first embodiment. In FIG. 14, in which parts corresponding to those in FIG. 12 are assigned the same reference numerals, this modification is shown in FIG. Instead of the optical path synthesizer 26 shown in the second modification example, a reflective film (for example, aluminum) is partially formed on a parallel plane plate inclined at 45 ° with respect to the optical axes of the primary relay optical systems 19A and 19B. An optical path combiner 61 provided with a partial reflection surface 61a made of a vapor deposition film is used. In this case, the light beam from the primary relay optical system 19A passes through the transmission part of the optical path combiner 61 and enters the secondary relay optical system 22, and the light beam from the primary relay optical system 19B is a part of the optical path combiner 61. The light is deflected by 90 ° at the reflecting surface 61 a and enters the secondary relay optical system 22. The configuration of the optical path combiner 61 of this modification is also simple.

[Fifth Modification of First Embodiment]
FIG. 15 shows a main part of an illumination optical system according to a fifth modification of the first embodiment. In FIG. 15, in which parts corresponding to those in FIG. 1 and FIG. In place of the optical path combining mirror 21 of the first embodiment of FIG. 1, an optical path combiner 63 comprising a one-dimensional prism array having refractive surfaces 63a and 63b that are symmetrically inclined so as to sandwich the boundary line 63c is used. is there. In this modification, the primary relay optical system 19A, the movable blind 18A of FIG. 1 in the preceding stage, the optical axis of the first optical system comprising the illumination unit IUA, and the primary relay optical system 19B, FIG. The optical axis of the second optical system composed of the movable blind 18B and the illumination unit IUB is that of the secondary relay optical system 22 after being refracted by the refractive surfaces 63a and 63b of the optical path combiner 63 in FIG. It is inclined symmetrically so as to be parallel to the optical axis. That is, the light beams from the primary relay optical systems 19A and 19B are incident on the refracting surfaces 63a and 63b of the optical path combiner 63 and are coaxially combined. In this case, the linear boundary line 63c that makes the refractive surfaces 63a and 63b of the optical path combiner 63 discontinuous is located on the reticle conjugate surface 62 or a surface in the vicinity thereof. As a result, the light beams from the primary relay optical systems 19A and 19B can be reliably irradiated onto different pattern areas on the reticle surface. According to this modification, the optical path bending mirrors 20A and 20B in the example of FIG. 1 can be omitted, and the configuration of the illumination optical system can be simplified.

[Sixth Modification of First Embodiment]
Instead of the optical path combiner 63 in FIG. 15, a Fresnel zone plate type or phase grating type one-dimensional refracting member 64 shown in FIG. 16 may be used.
[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. This example also applies the present invention when exposure is performed using a scanning stepper type projection exposure apparatus. In FIGS. 17 to 20, parts corresponding to FIGS. Detailed description thereof will be omitted. This example is different from the first embodiment in that a plurality of reticles arranged side by side in the scanning direction are used instead of providing a plurality of pattern regions (patterns) on one reticle. There is a predetermined scanning direction interval between the plurality of reticles, but the interval between the plurality of shot regions on the corresponding wafer is a linear narrow street line region as in the first embodiment. An image shifter is provided in the projection optical system.

  FIG. 17 shows the main part of the projection exposure apparatus of this example. In FIG. 17, this projection exposure apparatus has two light sources obtained by branching an exposure light source (not shown) and exposure light emitted from the exposure light source. An illumination optical system IU1 that illuminates a plurality (two in this case) of reticles R1A and R1B with illumination regions 25B and 25A under mutually independent illumination conditions with exposure light IL1 and IL2, and reticles R1A and R1B in the Y direction (scanning direction) A reticle stage RST1 that is sucked and held via a fine movement stage (not shown) at a predetermined interval and moves on the reticle base (not shown) in the Y direction, and patterns in the illumination areas 25B and 25A of the reticles R1A and R1B. A projection optical system PL1 that projects an image on the exposure areas 28B and 28A on the wafer W in a reduced scale, and the wafer W is sucked and held via a wafer holder WH, in the X and Y directions. Comprises a wafer stage WST that moves, the main control system 36 and a stage drive system 35 and the same control system of Figure 1 and the (not shown). In this case, each fine movement stage on reticle stage RST1 can independently adjust the positions of reticles R1A and R1B in the X, Y, and Z directions, and the rotation angles around X, Y, and Z axes. .

  FIG. 18A shows reticles R1A and R1B on reticle stage RST1 in FIG. 17, and patterns A and B are formed in the pattern areas in light-shielding bands LSTA and LSTB of reticles R1A and R1B, respectively. As shown in FIG. 4A, the patterns A and B are actually composed of an L & S pattern 55Y in the Y direction and an L & S pattern 55X in the X direction, respectively, as an example. Therefore, as the illumination method for the patterns A and B, bipolar illumination in the Y direction and the X direction is used, respectively.

  Returning to FIG. 17, the illumination optical system IU1 of this example is similar to the illumination optical system IU of the first modification of the first embodiment of FIG. 11 and the optical axes AX2a and AX4a of the illumination units IUA and IUB. The optical axes AX2b and AX4b of the relay optical systems 19A and 19B are arranged non-coaxially (however, they may be coaxial), but the boundary between the two reflecting surfaces 29A and 29B instead of the optical path combining mirror 21 The difference is that a trapezoidal optical path combining mirror 29 is used in a cross section in which 29C is a flat portion. For this reason, in the illumination optical system IU1 of this example, the illumination regions 24A and 24B formed on the reticle conjugate surface 62 (the boundary 29C is in the vicinity thereof), and the secondary relay optical system 22 from these illumination regions. The illumination regions 25A and 25B formed on the reticle surface (here, the pattern surfaces of the reticles R1A and R1B) through the gaps in the Y direction between the pattern regions of the reticles R1A and R1B in the scanning direction (Y direction) in a fully opened state. A minute away.

  FIG. 18B shows the field of view PL1F of the projection optical system PL1 of this example and the illumination fields 18AP and 18BP by the exposure lights IL1 and IL2 formed at the above-mentioned intervals in the Y direction so as to be substantially inscribed therein. A relationship is shown, and illumination areas 25A and 25B are opened and closed in the scanning direction in these illumination fields 18AP and 18BP. In this case, when a normal projection optical system is used, the interval between the exposure regions corresponding to the illumination regions 25A and 25B is increased by the reduction magnification of the projection optical system corresponding to the interval between the pattern regions of the reticles R1A and R1B. However, since the interval between shots on the wafer W is a narrow interval corresponding to the street line, the pattern of the two reticles R1A and R1B can be directly transferred to the Y on the wafer W via the projection optical system in one scanning exposure. It cannot be transferred to two shot areas adjacent in the direction.

  Therefore, the projection optical system PL1 of the present example projects the image of the pattern in the illumination areas 25A and 25B that are open in the Y direction on the object plane with a small interval so as to be adjacent to the Y direction on the image plane. An image shifter is provided. That is, in the projection optical system PL1 of this example, as shown in FIG. 17, the optical member group (including lenses, mirrors, etc.) PL1a among the optical members constituting the projection optical system is closer to the reticle side. A first image shifter P1 having a function of narrowing the interval between the light beams that have passed through the illumination areas 25A and 25B in the Y direction, which is made of a roof-shaped prism-shaped light transmitting member having a ridge line in the X direction in order from the reticle side; A function of a light transmitting member having a V-shaped cross-sectional shape complementary to the image shifter P1, and returning the traveling direction of the two light fluxes, which are closely spaced from each other, to the traveling direction when entering the image shifter P1 And a second image shifter P2 having

  As a result, as shown in FIG. 18C, the interval in the Y direction of the exposure areas 28A and 28B when fully opened in the image field PL1G of the projection optical system PL1 is equal to the width of the street line between shots on the wafer W. The patterns of the two reticles R1A and R1B shown in FIG. 17 can be transferred to two shot areas adjacent to each other in the Y direction on the wafer W under the respective optimal illumination conditions with the same narrow interval. .

[Scanning Exposure Operation of Second Embodiment]
Assuming that shot areas adjacent in the Y direction on wafer W in FIG. 17 are shot areas 48A and 48F in FIG. 20A, two reticles R1A and R1B (FIG. 19A) are obtained by one scanning exposure. 19 (a) to 20 (l) and 20 (a) to 20 (a) to 20 (a) to 20 (a) to 20 (a). This will be described with reference to l).

  FIGS. 19A to 19L show the positional relationship between the reticles R1A and R1B and the two illumination areas 25A and 25B in FIG. 17, respectively, at the time of scanning exposure, as in FIGS. FIG. 20A to 20L are shot regions 48A and 48F on the wafer W in the case of FIGS. 19A to 19L and two exposure regions 28A and 28B by the projection optical system PL1 in FIG. It is a figure which shows these positional relationships.

  First, when the pattern area of the reticle R1A enters the illumination field 18BP of FIG. 18B, the second illumination area 25B starts to open as shown in FIG. 19B (in the corresponding FIG. 20B). In FIG. 19C, FIG. 19D, and FIG. 19E, only the pattern of the reticle R1A is illuminated by the fully-open illumination area 25B, and the corresponding FIG. ), (D), and (e), only the shot area 48F is exposed in the fully open exposure area 28B.

  Next, when the pattern area of the reticle R1B enters the illumination field 18AP of FIG. 18B, the first illumination area 25A starts to open as shown in FIG. 19F (corresponding FIG. 20F). Then, the exposure area 28A on the shot area 48A begins to open), and then the reticles R1A and R1B are simultaneously illuminated by the illumination areas 25B and 25A up to FIGS. 19G and 19H (FIGS. 20G and 20H). The shot areas 48A and 48F are simultaneously exposed in the exposure areas 28A and 28B). Thereafter, as shown in FIGS. 19 (i) to (l), only the pattern area of the reticle R1B is illuminated by the first illumination area 25A (in the corresponding FIGS. 20 (i) to (l), only the shot area 48A is illuminated. Are exposed in the exposure area 28A), the reduced images of the patterns of the two reticles R1A and R1B are transferred to the two adjacent shot areas 48F and 48A on the wafer W. Thereafter, as in the first embodiment, the wafer W is stepped in the Y direction by one shot area and the above exposure is performed, so that two reticles are formed in one shot area on the wafer W. The R1A and R1B patterns can be double-exposed with high throughput. Note that it is not always necessary to perform double exposure, and different device patterns may be exposed to adjacent shot regions on the wafer W.

As described above, according to this example, since the projection optical system PL1 including the image shifters P1 and P2 is used, a plurality of reticle patterns arranged at predetermined intervals in the Y direction can be obtained by one scanning exposure. In addition, it is possible to transfer to a plurality of adjacent shot areas on the wafer W with high throughput under optimum illumination conditions.
[Modification of Second Embodiment]
FIG. 21 is a diagram of the projection optical system PL2 and the reticle stage RST1 of the projection exposure apparatus according to the modification of the second embodiment viewed from the scanning direction (+ Y direction), and FIG. 22 is the projection optical system PL2 and reticle of FIG. FIG. 23A is a view of the stage RST1 viewed from the non-scanning direction (+ X direction), and FIG. 23A shows a plurality (two in this case) of reticles R1A and R1B on the reticle stage RST1 of FIG. FIG. 23B is a diagram showing a positional relationship between the illumination fields 18BP and 18AP in the fields of view PL2FB and PL2FA of the projection optical system PL2, and FIG. 23B shows two exposure areas when fully opened in the image field PL2G of the projection optical system PL2 in FIG. 28A and 28B are shown.

  The projection optical system PL2 of this modification is a catadioptric imaging optical system having one or more concave reflecting mirrors. As shown in FIG. 21, the projection optical system PL2 has optical axes AX10A and AX10B parallel to each other. Positioned on a plurality of (here two) first groups G1A, G1B positioned above and optical axes AX11A, AX11B orthogonal to the optical axes AX10A, AX10B of the plurality of first groups G1A, G1B, Second group G2A and G2B each including concave reflecting mirrors McA and McB, and third group G3 including a plurality of lens elements positioned on optical axis AX12 orthogonal to optical axes AX11A and AX11B of second groups G2A and G2B. And. The projection optical system PL2 further reflects the light beam from the first group G1A toward the second group G2A, and reflects the light beam from the second group G2B toward the third group G3, and the first mirror M1. A plane mirror M2 that reflects the light beam from the group G1B toward the second group G2B and reflects the light beam from the second group G2A toward the third group G3; these plane mirrors M1, M2, and the third group G3; Image shifters P1 and P2 (which have the same shape as the image shifters P1 and P2 in FIG. 17) positioned in the optical path between them.

  The first group G1A and the second group G2A form an intermediate image of the pattern of the reticle R1A in the optical path near the plane mirror M2, and the first group G1B and the second group G2B convert the intermediate image of the pattern of the reticle R1B to the plane mirror. It is formed in the optical path near M1. The plurality of intermediate images are narrowed in the scanning direction by image shifters P1 and P2 having functions similar to those of the image shifters P1 and P2 of the second embodiment (FIG. 17), and the wafer is interposed via the third group G3. Re-imaging is performed on the wafer W held on the stage WST.

  Here, in the projection optical system PL2 of this modification, each of the plane mirrors M1 and M2 has a reflecting surface formed on both surfaces of a parallel plane plate-like optical member, and therefore the optical axis AX12 of the third group G3. The optical axes AX10A and AX10B of the first group G1A and G1B are not coaxial (although they are parallel to each other). Therefore, in this modification, the positions of the plurality of reticles R1A and R1B on the reticle stage RST1 in the non-scanning direction (X direction) are as much as the interval between the optical axes AX10A and AX10B as shown in FIG. The position is shifted. Thereby, as shown in FIG. 18B, the positions of the two exposure regions 28A and 28B in the image field PL2G (on the wafer W) of the projection optical system PL2 can be matched.

In addition, the shape of the optical element which comprises 1st group G1A and G1B has a substantially half-moon shape substantially similar to the visual field PL2FB and PL2FA of Fig.23 (a), respectively.
The projection optical system PL2 of the present modification includes a first imaging optical system including a first group G1A, a second group G2A, and a third group G3, a first group G1B, a second group G2B, and a third group. And a second imaging optical system made of G3. Therefore, an imaging characteristic control device (not shown) (for example, a mechanism for driving the optical member to be controlled in the optical axis direction and the rotational direction around two orthogonal axes in a plane perpendicular to the optical axis. The position and orientation of the optical members constituting the plurality of first groups G1A and G1B, which are optical members between the reticle surface and the image shifters P1 and P2, and / or By controlling the position and orientation of the optical members constituting the second group G2A, G2B, the image formation state of the image formed on the wafer W by the light beam from the reticle R1A and the wafer W by the light beam from the reticle R1B are controlled. The image formation state of the image formed on the top can be controlled independently.

  Further, in the projection optical system PL2 shown in FIGS. 21 and 22, the aperture stop AS is positioned in the third group G3, but this aperture stop is in the vicinity of the concave reflecting mirrors McA and McB in the second groups G2A and G2B. Can be provided. Thus, if a plurality of aperture stops are provided in the second group G2A, G2B, the coherence factor (σ value) related to the first imaging optical system through which the light beam from the reticle R1A passes and the light beam from the reticle R1B It is possible to independently control the σ value related to the second imaging optical system that passes through.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS. This example also applies the present invention when exposure is performed using a scanning stepper type projection exposure apparatus. In FIG. 24 to FIG. 30, portions corresponding to FIG. 1 to FIG. Detailed description thereof will be omitted. In this example, unlike the first embodiment, the optical path combiner also serves as a part of the function of the movable blind.

  FIG. 24 shows a schematic configuration of the projection exposure apparatus of this example. In FIG. 24, exposure light (exposure illumination light) IL made of linearly polarized ultraviolet pulse laser light emitted from the exposure light source 10 is mirror 71. After being reflected by the light beam, the light beam is divided into the first exposure light beam IL1 and the second exposure light beam IL2 by the light splitter 72 having a two-sided mirror, and the exposure light beams IL1 and IL2 are reflected by the mirrors 12A and 12B, respectively, to be symmetrical. Is incident on the first lighting unit IUA2 and the second lighting unit IUB2. The exposure lights IL1 and IL2 are polarized light control units 13A and 13B, exchangeable diffractive optical elements 14A and 14B, shaping optical systems 15A and 15B, optical path bending mirrors 20A and 20B, optical integrators 16A and 16B, and condensers, respectively. Reflected by orthogonal reflecting surfaces 73a and 73b of a movable optical path combining mirror 73 via illumination units IUA2 and IUB2 including optical systems 17A and 17B, the reticle conjugate surface 62A (reticle surface and secondary relay optical system 22A described later) Illuminate the optically conjugate surface).

  FIG. 25 is a diagram schematically showing the illumination optical system IU2 of this example of FIG. 24. As shown in FIG. 25, the ridgeline 73c at the boundary between the two reflecting surfaces 73a and 73b of the optical path combining mirror 73 is shown in FIG. The movable blinds 18A1 and 18B1 for the illumination units IUA2 and IUB2 are located on the reticle conjugate surface 62A, and are spaced from the ridgeline 73c by a drive mechanism (not shown). Are arranged so that they can be controlled independently. In addition, fixed blinds 31 for illumination units IUA2 and IUB2 are arranged at a position slightly defocused from reticle conjugate surface 62A. The fixed blinds 31A and 31B of the first embodiment shown in FIG. 1 are positioned upstream of the movable blinds 18A and 18B and slightly defocused from the reticle conjugate plane 62. The fixed blind 31 of this example is different in that it is disposed at a position slightly defocused from the reticle conjugate surface 62A on the downstream side of the movable blinds 18A1 and 18B1.

In addition, the variable slit currently disclosed by the international publication 2005/048326 pamphlet can also be arrange | positioned in the position of fixed blind 31A, 31B or 31 of each embodiment, for example. If this structure is taken, it becomes possible to control the illumination nonuniformity for every some illumination field independently.
Further, the optical path combining mirror 73 of the present example is configured so that the ridge line 73c moves within the opening of the fixed blind 31 along the reticle conjugate surface 62A by the drive mechanism 74 such as a linear motor including the mover 74a and the stator 74b. Driven. The movable blinds 18A1 and 18B1 are driven so as to open and close the opening between the ridgeline 73c and the end of the fixed blind 31, respectively. The optical path combining mirror 73 and the movable blinds 18A1 and 18B1 are driven in accordance with the position of the reticle R in the scanning direction by a drive system (not shown) similar to the stage drive system 35 of FIG.

  Returning to FIG. 24, the exposure lights IL1 and IL2 that have passed through the openings of the movable blinds 18A1 and 18B1 and the fixed blind 31 shown in FIG. 25 pass through the secondary relay optical system 22A including the lens system 22f from the lens system 22Aa. The pattern provided on the R pattern surface (reticle surface) is illuminated. The illumination optical system IU2 includes the illumination units IUA2 and IUB2, the movable blinds 18A1 and 18B1, the fixed blind 31, the movable optical path combining mirror 73, and the secondary relay optical system 22A.

  As shown in FIG. 25, illumination regions 75A and 75B (openings between the ridgeline 73c of the optical path combining mirror 73 and the movable blinds 18A1 and 18B1) formed on the reticle conjugate surface 62A by the exposure light from the illumination units IUA2 and IUB2 ) Is re-imaged by the secondary relay optical system 22A as a first illumination region 76A and a second illumination region 76B adjacent to each other on the reticle R in the scanning direction (Y direction). As described above, in this example, the ridgeline 73c of the optical path combining mirror 73 also functions as the other movable blind of the movable blinds 18A1 and 18B1. Hereinafter, an opening between the movable blind 18A1 and the ridgeline 73c is referred to as an opening of the movable blind 18A1, and an opening between the movable blind 18B1 and the ridgeline 73c is referred to as an opening of the movable blind 18B1.

  FIG. 26A shows the first illumination field 77A and the second illumination field 77B, which are images of the field of view PLF of the projection optical system PL of this example and the opening portions of the movable blinds 18A1 and 18B1 shown in FIG. In FIG. 26 (a), the first illumination field 77A and the second illumination field 77B have the same size and the same position as the contour of the field of view PLF of the projection optical system PL. Almost inscribed. The illumination areas 76A and 76B in FIG. 25 are opened and closed so as not to overlap each other in the illumination fields 77A and 77B, respectively. The illumination fields 77A and 77B in FIG. 26A are approximately twice as wide in the scanning direction as the illumination fields 18AP and 18BP in FIG. 3 of the first embodiment.

  As a result, in the image field PLG of the projection optical system PL shown in FIG. 26B, the exposure areas 78A and 78B corresponding to the illumination areas 76A and 76B when fully opened are the same area, and the width in the scanning direction is the first. This is almost twice that of the embodiment. Accordingly, the integrated exposure amount at the time of scanning exposure on the wafer W is almost doubled as compared with the first embodiment, and the scanning speed of the wafer W can be increased to improve the throughput. Further, since the number of exposure light irradiation pulses on the wafer W increases, unevenness in illuminance is reduced. In the first embodiment, a light source with a short pulse emission interval (a light source with a high pulse emission frequency) is used as the exposure light source 10 so that the width of the illumination field in the scanning direction is almost half that in this example. Uneven illumination can be reduced.

Referring back to FIG. 24, the pattern in the illumination area on the reticle R under the exposure lights IL1 and IL2 has a predetermined projection magnification β (β is 1/4, 1/5, etc.) via the projection optical system PL. Is projected onto the exposure area on the wafer W. The other configuration is the same as that of the first embodiment.
Next, an example of the exposure operation of the projection exposure apparatus of this example will be described. As shown in FIG. 27A, the pattern surface of the reticle R in this example is divided into two pattern regions RA and RB in the Y direction by a light shielding band 53 at the boundary, and each of the pattern A in the pattern regions RA and RB And B are formed. Then, images of the patterns A and B of the two pattern areas RA and RB of the reticle R are exposed to two shot areas adjacent in the scanning direction on the wafer W by one scanning exposure.

  FIGS. 27A to 27L are diagrams showing the positional relationship between the plurality of pattern areas RA and RB of the reticle R and the two illumination areas 76A and 76B in FIG. 25 at the time of scanning exposure. FIGS. 28A to 28D show the states of the opening portions (one of which is defined by the ridge line 73c) of the movable blinds 18A1 and 18B1 in the case of FIGS. 27A to 27D, respectively. 29 (e) to (h) show the states of the openings of the movable blinds 18A1 and 18B1 in the case of FIGS. 27 (e) to (h), respectively, and FIGS. The state of the opening part of movable blind 18A1, 18B1 in the case of (i)-(l) is shown.

  Then, when the scanning of the reticle R in the + Y direction is started and the pattern area RA of the reticle R enters the illumination field 77B of FIG. 26A, the second illumination area as shown in FIG. 76B begins to open (the movable blind 18B1 starts to open in the corresponding FIG. 28B), and in the state where only the pattern area RA passes through the illumination field 77B in FIG. As shown in d) and (e), the reticle R is scanned with respect to the second illumination area 76B (in the corresponding FIGS. 28C, 28D, and 29E, only the movable blind 18B1 is open). is there). As a result, only the pattern image of the first pattern area RA of the reticle R is sequentially exposed to one shot area of the wafer W.

  Next, as shown in FIG. 27 (f), when the pattern area RA of the reticle R is illuminated by the second illumination area 76B, the pattern area RB enters the illumination field 77A of FIG. As soon as the first illumination area 76A begins to open, the second illumination area 76B begins to close (the movable blind 18A1 begins to open and the movable blind 18B1 begins to close in the corresponding FIG. 29 (f)), and the illumination area in FIG. 27 (g). 76A and 76B have the same size (half the maximum width) (the openings of the movable blinds 18A1 and 18B1 are symmetric in the corresponding FIG. 29G). Before and after this state, the image of the ridge line 73c of the optical path combining mirror 73 in FIG. 25 moves in the Y direction following the light shielding band at the boundary between the two pattern areas RA and RB in FIG.

  Thereafter, when the reticle R is further scanned in the + Y direction, the second illumination area 76B is closed as shown in FIG. 27 (h) (the movable blind 18B1 is closed in the corresponding FIG. 29 (h)). 27 (i), the first illumination area 76A is fully opened, and only the second pattern area RB of the reticle R is illuminated by the first illumination area 76A (in the corresponding FIG. 30 (i)). The movable blind 18B1 is completely closed). Thereafter, as shown in FIGS. 27 (j) to (l), only the second pattern region RB of the reticle R is illuminated with the first illumination region 76A (in the corresponding FIGS. 30 (j) to (l), the movable blind The image of the pattern in the second pattern region RB is sequentially exposed to the second shot region of the wafer W. Thereafter, the wafer W is stepped in the Y direction by the width of one shot area and the above-described scanning exposure is performed, so that the pattern in the pattern areas RA and RB of the reticle R is double exposed in the intermediate shot area. Is done.

  Thus, according to this example, as shown in FIG. 24, the optical path combining mirror 73 is moved in synchronization with the scanning of the reticle R, and is also used as one of the movable blinds 18A1 and 18B1. The movable blind mechanism can be simplified. Furthermore, since the plurality of pattern areas RA and RB of the reticle R can be illuminated with a wide illumination area that is substantially inscribed in the visual field of the projection optical system PL, the integrated exposure amount increases on the wafer W and the scanning speed of the wafer W increases. Thus, the throughput of the exposure process can be improved.

  In the exposure apparatus (projection exposure apparatus) of the above-described embodiment, after installing a column mechanism (not shown), an illumination optical system composed of a plurality of optical members and a projection optical system are incorporated into the exposure apparatus main body for optical adjustment. Then, it can be manufactured by attaching a reticle stage or wafer stage made up of a large number of mechanical parts to the exposure apparatus main body, connecting wiring and piping, and performing total adjustment (electrical adjustment, operation check, etc.). The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  Further, when a semiconductor device is manufactured using the exposure apparatus of the above-described embodiment, the semiconductor device includes a step of designing a function and performance of the device, a step of manufacturing a reticle based on this step, and a wafer from a silicon material. Forming, aligning with the projection exposure apparatus of the above embodiment to expose the pattern of the reticle onto the wafer, forming a circuit pattern such as etching, device assembly step (dicing process, bonding process, packaging process) Including) and an inspection step.

  The present invention can be applied not only to a scanning exposure type projection exposure apparatus but also to a batch exposure type (stepper type) projection exposure apparatus. The present invention can also be applied to the case where exposure is performed with an immersion type exposure apparatus disclosed in, for example, WO 99/49504. In this case, at the time of scanning exposure, in FIG. 1, a liquid such as pure water is locally supplied between the projection optical system PL and the wafer W from a liquid recovery apparatus (not shown), and the supplied liquid is not shown. It is recovered by the liquid recovery device.

The present invention can also be applied to the case where exposure is performed with a projection exposure apparatus that uses extreme ultraviolet light (EUV light) having a wavelength of about several nm to 100 nm as an exposure beam.
In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an image sensor (CCD or the like), a micromachine, a thin film magnetic head, and a DNA chip. Furthermore, the present invention can also be applied to an exposure process (exposure apparatus) when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process. As described above, the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be taken without departing from the gist of the present invention.

  According to the present invention, patterns of adjacent pattern areas on a mask can be transferred onto a photosensitive substrate under optimum illumination conditions. Therefore, for example, since double exposure can be performed with high throughput under optimum illumination conditions, a device having a fine pattern can be manufactured with high accuracy.

It is a figure which shows the structure of the projection exposure apparatus of the 1st Embodiment of this invention. It is a figure which shows schematically the illumination optical system IU of the projection exposure apparatus of FIG. It is a figure which shows the relationship between the visual field of the projection optical system PL of the projection exposure apparatus of FIG. 1, and an illumination field. It is a figure which shows an example of the change of the positional relationship of pattern area | region RA, RB of the reticle R of FIG. 2, and illumination area | region 25A, 25B. It is a figure which shows an example of the change of the opening part of movable blind 18A, 18B corresponding to the change of the state of the 1st line of FIG. It is a figure which shows an example of the change of the opening part of movable blind 18A, 18B corresponding to the change of the state of the 2nd line of FIG. It is a figure which shows an example of the change of the opening part of movable blind 18A, 18B corresponding to the change of the state of the 3rd line of FIG. It is a top view which shows an example of the shot arrangement | sequence on the wafer of 1st Embodiment. FIG. 9 is a plan view for explaining the case where exposure is performed on the second and third shot areas on the wafer of FIG. 8. FIG. 9 is a plan view for explaining the case where exposure is performed on the third and fourth shot areas on the wafer of FIG. 8. It is a figure which shows the principal part of the illumination optical system of the 1st modification of 1st Embodiment. It is a figure which shows the principal part of the illumination optical system of the 2nd modification of 1st Embodiment. It is a figure which shows the principal part of the illumination optical system of the 3rd modification of 1st Embodiment. It is a figure which shows the principal part of the illumination optical system of the 4th modification of 1st Embodiment. It is a figure which shows the principal part of the illumination optical system of the 5th modification of 1st Embodiment. It is a figure which shows the optical member which can be used instead of the optical path combiner 63 of embodiment of FIG. It is a figure which shows schematic structure of the projection exposure apparatus of the 2nd Embodiment of this invention. 17A is a plan view showing the two reticles of FIG. 17, FIG. 17B is a plan view showing the relationship between the field of view and the illumination field of the projection optical system PL1 of FIG. 17, and FIG. 17C is the projection optical system of FIG. It is a top view which shows the relationship between the image field of PL1, and an exposure area | region. It is a figure which shows an example of the change of the positional relationship of the pattern area | region of two reticles of FIG. 17, and illumination area | region 25A, 25B. It is a figure which shows an example of the change of the positional relationship of two adjacent shot area | regions on the wafer corresponding to the change of the state of FIG. 19, and exposure area | region 28A, 28B. It is the figure which looked at the projection optical system and reticle stage of the modification of 2nd Embodiment from the scanning direction. It is the figure which looked at the 21st projection optical system and the reticle stage from the non-scanning direction. FIG. 22A is a plan view showing two reticles on the reticle stage in FIG. 21, and FIG. 22B is a plan view showing the relationship between an image field and an exposure area of the projection optical system in FIG. It is a figure which shows schematic structure of the projection exposure apparatus of the 3rd Embodiment of this invention. It is a figure which shows schematically the illumination optical system IU2 of the projection exposure apparatus of FIG. (A) is a figure which shows the relationship between the visual field and projection field of projection optical system PL of FIG. 24, (b) is a figure which shows the relationship between the image field of projection optical system PL of FIG. 24, and an exposure area | region. FIG. 25 is a diagram showing an example of a change in the positional relationship between the pattern areas RA and RB of the reticle R in FIG. 24 and the illumination areas 76A and 76B. It is a figure which shows an example of the change of the opening part of movable blind 18A1, 18B1 corresponding to the change of the state of the 1st line of FIG. It is a figure which shows an example of the change of the opening part of movable blind 18A1, 18B1 corresponding to the change of the state of the 2nd line of FIG. It is a figure which shows an example of the change of the opening part of movable blind 18A1, 18B1 corresponding to the change of the state of the 3rd line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Exposure light source, IU ... Illumination optical system, IUA, IUB ... Illumination unit, 18A, 18B ... Movable blind, 19A, 19B ... Primary relay optical system, 21, 73 ... Optical path composition mirror, 22, 22A ... Secondary relay Optical system, 25A, 25B ... illumination area, 28A, 28B ... exposure area, 29 ... optical path synthesis mirror, 31A, 31B ... fixed blind, R, R1A, R1B ... reticle, PL, PL1, PL2 ... projection optical system, W ... Wafer

Claims (25)

In an illumination optical apparatus that is used in a projection exposure apparatus that projects and exposes a pattern arranged on a first surface onto a second surface, and supplies illumination light from a light source to the first surface,
A relay optical system disposed between the light source and the first surface, and forming a third surface optically conjugate with the first surface between the light source and the first surface;
A first light beam from the light source and a second light beam that is different from the first light beam are arranged in the optical path between the light source and the first surface, and are close to each other on the first surface. An optical path synthesizer that synthesizes to irradiate;
With
The optical path combiner includes a first region corresponding to the first light flux, and a second region corresponding to the second light flux separated from the first region,
The boundary between the first region and the second region is disposed on the third surface or in the vicinity of the third surface. The light source is one;
The illumination optical apparatus according to claim 1, further comprising a multi-beam generator that branches the illumination light from the light source into the first and second light beams.   The illumination optical apparatus according to claim 1, wherein the light source includes a first light source that supplies the first light beam and a second light source that supplies the second light beam.   4. The illumination optical apparatus according to claim 1, wherein at least one of the first region and the second region of the optical path combiner includes a reflecting surface. 5.   The illumination optical apparatus according to claim 4, wherein both the first region and the second region of the optical path combiner include a reflecting surface.   4. The illumination optical apparatus according to claim 1, wherein at least one of the first region and the second region of the optical path combiner includes a refracting surface. 5.   2. The apparatus according to claim 1, further comprising: a first movable blind disposed in an optical path of the first light flux; and a second movable blind disposed in an optical path of the second light flux. The illumination optical apparatus according to claim 6. A first preceding relay optical system disposed in an optical path between the first movable blind and the third surface;
The illumination optical apparatus according to claim 7, further comprising a second preceding relay optical system disposed in an optical path between the second movable blind and the third surface. A first and a second lighting unit for supplying the first and second light fluxes to the first and second movable blinds, respectively;
The first illumination unit and the first previous relay optical system are arranged coaxially, and the second illumination unit and the second previous relay optical system are arranged coaxially. The illumination optical apparatus according to claim 8. A first and a second lighting unit for supplying the first and second light fluxes to the first and second movable blinds, respectively;
The first illumination unit and the first front relay optical system are arranged non-coaxial, and the second illumination unit and the second front relay optical system are arranged non-coaxial. 9. The illumination optical apparatus according to claim 8, wherein   11. The optical path combiner is capable of scanning in a direction corresponding to a direction in which the first light flux and the second light flux are separated on the first surface. The illumination optical device according to Item.   The illumination optical apparatus according to any one of claims 1 to 11, wherein the first light flux and the second light flux have different incident angle distributions when entering the first surface. .   The illumination optical device according to any one of claims 1 to 12, wherein the first light beam and the second light beam have different polarization states when entering the first surface.   The illumination optical device according to any one of claims 1 to 13, wherein the first light flux and the second light flux have different illuminances on the first surface. In an illumination optical apparatus that is used in a projection exposure apparatus that projects and exposes a pattern arranged on a first surface onto a second surface, and supplies illumination light from a light source to the first surface,
An optical path combiner that is disposed in an optical path between the light source and the first surface and synthesizes the plurality of different light fluxes from the light source so as to be closely irradiated on the first surface;
The optical path combiner includes a third surface optically conjugate with the first surface or a discontinuous point positioned in the vicinity of the third surface,
The illumination optical apparatus according to claim 1, wherein the plurality of light beams pass through a plurality of regions partitioned by the discontinuous points.   The illumination optical apparatus according to claim 15, wherein the discontinuous point of the optical path combiner is extended in a linear shape. In a projection exposure apparatus that illuminates a pattern with illumination light and exposes a photosensitive substrate through the pattern and the projection optical system,
A projection exposure apparatus comprising the illumination optical apparatus according to any one of claims 1 to 16 for illuminating the pattern.   The projection optical system according to claim 17, wherein the projection optical system includes an image shifter that shifts a relative position between an image formed by the first light beam and an image formed by the second light beam. Exposure device. The projection exposure apparatus moves and exposes the photosensitive substrate arranged on the second surface in a corresponding direction in synchronization with the movement of the pattern arranged on the first surface in a predetermined scanning direction. Scanning exposure type that performs
The projection exposure apparatus according to claim 17, wherein the pattern arranged on the first surface has a plurality of pattern regions arranged along the scanning direction. Illuminating the first and second pattern regions arranged along a predetermined scanning direction with the first and second light fluxes, respectively,
The pattern having the first and second pattern areas is moved in the scanning direction in a state where the photosensitive substrate is exposed with the first and second light fluxes that have passed through the first and second pattern areas, respectively. Synchronously move the substrate in the corresponding direction,
In the projection exposure apparatus for transferring the patterns of the first and second pattern regions to the adjacent first and second partitioned regions on the substrate by one scanning exposure, respectively, the first and second pattern regions A projection optical system used for exposing the substrate with the first and second light beams that have passed through
A projection optical system comprising an image shifter that shifts a relative position between an image formed by the first light beam and an image formed by the second light beam.   The image formation characteristic of the image formed by the first light beam and the image formation characteristic of the image formed by the second light beam are arranged independently between the pattern arrangement surface and the image shifter. 21. The projection optical system according to claim 20, further comprising first and second imaging characteristic control devices that are controlled to each other.   20. A device manufacturing method using the projection exposure apparatus according to any one of claims 17 to 19. A device manufacturing method using the projection exposure apparatus according to claim 19,
The device manufacturing method, wherein the plurality of pattern regions are formed on one mask. A device manufacturing method using the projection exposure apparatus according to claim 19,
The device manufacturing method, wherein the plurality of pattern regions are formed on a plurality of masks. The pattern has first and second pattern regions arranged along the scanning direction,
While illuminating the first and second pattern regions with the first and second light beams, respectively, the patterns of the first and second pattern regions are adjacent to each other on the substrate by one scanning exposure. 25. The device manufacturing method according to claim 23, wherein transfer is performed to the first and second partition regions.

Images