JP2002372735A - Optical diaphragm device, exposure device, exposure method, method for manufacturing device, and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simply constituted optical diaphragm device having an improved image forming performance and an improved operability, an exposure device, an exposure method, and a method for manufacturing the device and the device. SOLUTION: The optical diaphragm device is provided with several nearly planar light shielding plates movably arranged so as to variably form an aperture, and a moving mechanism provided with a track surface having a prescribed curvature in an optical axis direction and a moving element which is placed on the track surface, also, connected to the light shielding plate and made movable on the track surface, the position and the size of the aperture is decided in accordance with the movement of the moving element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an exposure apparatus, and more particularly to an exposure apparatus used for exposing an object to be processed such as a single crystal substrate for a semiconductor wafer and a glass substrate for a liquid crystal display (LCD). The present invention relates to an exposure apparatus, an optical stop device used for the exposure apparatus, a method for manufacturing a device using the object, and a device manufactured from the object. The present invention is suitable for, for example, an exposure apparatus that exposes a single crystal substrate for a semiconductor wafer by projection exposure in a photolithography process.

[0002]

2. Description of the Related Art In recent years, with the demand for smaller and thinner electronic devices, there is an increasing demand for finer semiconductor elements mounted on the electronic devices, that is, higher resolution of transferred patterns. In order to meet such a demand, a projection exposure apparatus is mainly used in a lithography process.

A projection exposure apparatus generally uses an illumination optical system for illuminating a mask or a reticle (hereinafter, these terms are used interchangeably in this application) using a light beam emitted from a light source, a mask, and a mask. And a projection optical system disposed between the processing body.

The resolution R of the projection exposure apparatus is determined by the wavelength λ of the light source.
And the numerical aperture (NA) of the exposure apparatus.

[0005]

(Equation 1)

Therefore, the shorter the wavelength and the higher the NA, the better the resolution.

On the other hand, a focus range in which a certain imaging performance can be maintained is called a depth of focus, and the depth of focus DOF is given by the following equation.

[0008]

(Equation 2)

Therefore, the shorter the wavelength and the higher the NA, the smaller the depth of focus. As the depth of focus becomes smaller, focusing becomes difficult, and it is required to increase the flatness (flatness) and focus accuracy of the substrate.

In such a lithography process,
It is preferable that the projection exposure apparatus optimizes the NA of the projection optical system in order to improve the resolving power while securing the depth of focus. Therefore, the projection optical system incorporates an optical stop device having an aperture stop capable of changing the NA almost steplessly so that the NA can be selectively used. In such an optical stop device, the aperture stop exists at an ideal position regardless of the numerical aperture (that is, the exit pupil on the image side of the projection optical system is positioned at infinity (telecentric optical system)). Preferably, such an aperture stop is required to be able to change its position in the optical axis direction.

One of the image distortions is a distortion caused by the projection optical system. In order to correct such aberrations, it is necessary to set the aperture position of the optical diaphragm device to an object-side Fourier transform surface that converts light beams of various angles into parallel light beams on the object to be processed. In other words, an optical diaphragm device that makes the NA variable is
Ideally, the aperture is formed such that the arrangement position in the optical axis direction always becomes the Fourier transform plane on the object plane side according to NA.

As such a technique, for example, there is an optical aperture device proposed in Japanese Patent Application Laid-Open No. 1999-195607. According to such an optical diaphragm device, the size of the opening can be changed, and the position of the contour of the opening can be changed along the direction of the optical axis of the projection optical system. More specifically, such an optical device changes the size of the aperture along a curved pupil plane formed by an optical system provided above the stop of the projection optical system, and then changes the position in the optical axis direction. Is changed, or the size of the opening is changed in a predetermined plane, and the position of the predetermined plane in the optical axis direction is changed with the change in the size of the opening after that.

[0013]

According to the optical diaphragm device proposed in the above-mentioned Japanese Patent Application Laid-Open Publication No. 1999-195607, the optimum position in the optical axis direction for the NA of the projection optical system according to a predetermined arithmetic expression. Is calculated, and the size of the aperture stop and the position of the aperture stop in the optical axis direction are determined based on the calculation result. In the above publication, an aperture diameter adjusting mechanism and an optical axis direction adjusting mechanism are provided for each of the two axes of the optical axis direction and the direction perpendicular to the optical axis, so that the optical aperture device itself becomes large and the structure is increased. There was a disadvantage that it became complicated.

Accordingly, it is an exemplary object of the present invention to provide an optical diaphragm apparatus, an exposure apparatus, an exposure method, a device manufacturing method, and a device having a simple structure and excellent in imaging performance and operability.

[0015]

In order to achieve the above object, an optical diaphragm apparatus according to the present invention comprises a plurality of substantially flat light shielding plates movably provided to variably form an opening; A moving mechanism having a track surface having a predetermined curvature with respect to the optical axis direction and a movable member mounted on the track surface and connected to the light shielding plate and movable on the track surface; The position and the size of the opening are determined by the movement of the moving element. Such an optical diaphragm device can adjust the opening position together with the size of the opening with a simple configuration, and can prevent operability from being complicated. The curvature is preferably the curvature of the Fourier transform surface of the object surface, and such an optical diaphragm device has excellent imaging performance. The locus drawn by the position of the opening is
It is characterized in that it has substantially the same shape as at least a part of the Fourier transform plane of the object plane. In such an optical diaphragm device, the aperture can be arranged at an optimum position, and the imaging performance can be improved.

In the optical diaphragm device, the moving mechanism may further include a substrate having a spiral groove for determining a moving path of the moving element. Further, the track surface is a spiral surface centered on the optical axis, and in a cross section including the optical axis, an envelope of the spiral surface has at least a portion at least partially substantially the same shape as a Fourier transform surface of an object surface. It is characterized by. Further, the moving mechanism may further include a substrate having a groove formed in a radial direction for determining a moving path of the moving element.

An exposure apparatus according to still another aspect of the present invention includes the above-described optical diaphragm device, and projects a pattern formed on a mask or a reticle onto an object through the opening of the optical diaphragm device. It has an optical system. In such an exposure apparatus, for example, each time the mask is switched, the optical aperture device variably opens the opening, and at the same time, can be arranged at an optimum position in the optical axis direction.

According to another aspect of the present invention, there is provided an exposure apparatus including the above-described optical device, and an illumination optical system for illuminating a mask or a reticle having a pattern formed through the opening of the optical stop device. Have. Such an optical diaphragm device may be configured as, for example, an aperture diaphragm arranged after a fly-eye lens.

According to still another aspect of the present invention, there is provided an exposure method, wherein a step of determining an aperture and an optical axis direction position of the projection optical system by using a projection optical system having the above-described optical diaphragm device; Projecting the pattern formed on the mask onto the object using the projection optical system. This exposure method has the same operation as the above-described exposure apparatus.

A device manufacturing method according to still another aspect of the present invention includes a step of exposing the object using the above-described exposure apparatus, and a step of performing a predetermined process on the object subjected to the projection exposure. And The claims of the device manufacturing method having the same operation as that of the above-described exposure apparatus extend to the device itself as an intermediate and final product. Such a device is, for example, an LSI
And semiconductor chips such as VLSI, CCDs, LCDs, magnetic sensors, thin-film magnetic heads, and the like.

A further object or other feature of the present invention is that
The present invention will be clarified by preferred embodiments described below with reference to the accompanying drawings.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An exposure apparatus 1 according to an embodiment of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 9 is a schematic sectional view of the exposure apparatus 1 of the present invention. The exposure apparatus 1 includes, as shown in FIG.
, Mask 200, projection optical system 300, plate 4
00. The exposure apparatus 1 is, for example, a projection exposure apparatus that exposes a circuit pattern formed on the mask 200 to the plate 400 by a step-and-repeat method or a step-and-scan method. Such an exposure apparatus is suitable for a lithography process of submicron or quarter micron or less. Here, the “step-and-repeat method” refers to an exposure method in which the wafer is step-moved for each batch exposure of a shot of the wafer, and the next shot is moved to an exposure area. In the “step-and-scan method”, the wafer is continuously scanned with respect to the mask to expose the pattern of the mask onto the wafer, and after the exposure of one shot is completed, the wafer is step-moved to the exposure area of the next shot. This refers to a moving exposure method.

The illuminating device 100 illuminates the mask 200 on which a circuit pattern for transfer is formed, and has a light source unit 110 and an illumination optical system 120.

The light source unit 110 includes a laser 1 as a light source.
12 and a beam shaping system 114.

The laser 112 has an A of about 193 nm.
rF excimer laser, KrF excimer laser with a wavelength of about 248 nm, and _{F 2} excimer laser having a wavelength of about 153nm may be used. However, the type of laser is not limited to an excimer laser. For example, a YAG laser may be used, and the number of lasers is not limited. For example, if two independently operating solid state lasers are used, there is no coherence between the solid state lasers.
Speckle due to coherence is significantly reduced.
In order to further reduce speckle, the optical system may be swung linearly or rotationally. The light source that can be used for the light source unit 110 is not limited to the laser 112, and one or more lamps such as a mercury lamp and a xenon lamp can be used.

The beam shaping system 114 can use, for example, a beam expander having a plurality of cylindrical lenses, and converts the aspect ratio of the cross-sectional shape of the parallel light from the laser 112 into a desired value ( For example,
The beam shape is shaped into a desired shape by changing the cross-sectional shape from a rectangle to a square. Beam shaping system 114
Forms a light beam having the size and divergence angle required to illuminate the fly-eye lens.

Although not shown in FIG. 9, it is preferable that the light source unit 110 use an incoherent optical system for incohering a coherent laser beam. The incoherent optical system, for example, converts an incident light beam into at least two light beams (for example, p-polarized light and s-polarized light) at a light splitting surface as disclosed in FIG. After branching, one light beam is given an optical path difference greater than the coherence length of the laser beam to the other light beam via the optical member, and then is re-guided to the division surface to be superimposed on the other light beam and emitted. An optical system having at least one folding system as described above can be used.

The illumination optical system 120 is an optical system for illuminating the mask 200, and the optical integrator 13
0, an aperture stop 140, and a condenser lens 150. The laser 112, the incident surface 130a of the optical integrator 130, the mask 200, and the plate 400 are maintained in an optically conjugate relationship.

The optical integrator 130 is
Uniform illumination light illuminated on the mask 200, for example,
It is configured as a fly-eye lens that converts the angle distribution of the incident light into a position distribution and emits it. In the fly-eye lens, the entrance surface 130a and the exit surface 130b optically have a relationship between the object plane and the pupil plane (or the pupil plane and the image plane).

The fly-eye lens is formed by arranging a plurality of lenses (lens elements) on the other surface having different focal positions from each other. Further, when the cross-sectional shape of each lens element constituting the fly-eye lens is substantially similar to the illumination area of the illumination device when the lens surface of each lens element is spherical, the utilization efficiency of the illumination light is higher. This is because the fly-eye lens and the illumination area have a relationship between the pupil and the image. Each light beam from a plurality of point light sources (effective light sources) formed on or near the emission surface 130b of the fly-eye lens is superimposed on the mask 200 by the condenser lens 150. Thus, the entire mask 200 is uniformly illuminated by a number of point light sources (effective light sources).

The optical integrator 130 applicable to the present invention is not limited to the fly-eye lens. For example, a plurality of sets of cylindrical lens arrays arranged so that the generatrix of the cylindrical lenses constituting each set are orthogonal to each other. It may be. The fly-eye lens 130 may be replaced with an optical rod. The optical rod has a rectangular cross-section in which the illuminance distribution, which was non-uniform on the incident surface, is made uniform on the output surface, and the cross-sectional shape perpendicular to the rod axis has almost the same aspect ratio as the illumination area. If the optical rod has power in a cross-sectional shape perpendicular to the rod axis, the illuminance on the exit surface is not uniform, so the cross-sectional shape perpendicular to the rod axis is a polygon formed by only straight lines. Others
The fly-eye lens 130 may be replaced by a diffractive element having a diffusing effect. An optical diaphragm device 500 described later can also be applied to an aperture diaphragm.

Immediately after the exit surface 130a of the fly-eye lens 130, an aperture stop 140 whose shape and diameter are variable is provided. The aperture stop 140 has, for example, a circular aperture. Optionally, the aperture stop 140 may be, for example, as shown in FIG.
The light transmitting part 141 and the light shielding part 142 having a ring shape shown in FIG.
And 143 may be configured as a ring-shaped aperture stop 140A. Here, FIG.
FIG. 4 is a plan view of an aperture stop 140A applicable to the embodiment 40; Further, as shown in FIG. 10B, the aperture stop 140 may be configured as an aperture stop 140B having a light transmitting part 144 and a light shielding part 145. Here, FIG. 10B is a plan view of a quadrupole aperture stop 140B applicable to the aperture stop 140. FIG. The light transmitting portion 144 corresponds to the portions at ± 45 degrees and ± 135 degrees of the light transmitting portion 145. Aperture stop 140
A, 140B, when exposing the pattern of the mask 200,
This is effective as deformed illumination (or oblique incidence illumination) that increases the depth of focus near the limit resolution. The aperture stop 14
It is preferable that 0 is connected to a control mechanism (not shown) so that the opening diameter and the shape described above can be changed according to the lighting conditions.

The condenser lens 150 collects as much light as possible from the fly-eye lens 130 so that the chief rays are parallel, that is, telecentric.
0 is Koehler-illuminated. The mask 200 and the exit surface 130b of the fly-eye lens 130 are optically arranged in a relationship between the object plane and the pupil plane (or the pupil plane and the image plane).

The exposure apparatus 1 has a variable width slit for controlling illuminance unevenness and a masking blade (aperture or slit) for limiting an exposure area during scanning, if necessary. When a masking blade is provided, the masking blade and the exit surface 130b of the fly-eye lens 130 are optically arranged in a relationship between an object plane and a pupil plane (or a pupil plane and an image plane). The light beam transmitted through the opening of the masking blade is used as illumination light for the mask 200.

The mask 200 is made of, for example, quartz, on which a circuit pattern (or image) to be transferred is formed, and a first stage (“reticle stage”) not shown.
And may be called). Diffracted light emitted from the mask 200 passes through the projection optical system 300 and is projected onto the plate 400. The plate 400 is an object to be processed such as a wafer or a liquid crystal substrate, and is coated with a resist. The mask 200 and the plate 400 have a conjugate relationship. In the case of a step-and-scan type exposure apparatus (also called a “scanner”), the pattern of the mask 200 is transferred onto the plate 400 by scanning the mask 200 and the plate 400. Step-and-repeat type exposure apparatus (also called "stepper")
In the case of, the exposure is performed with the mask 200 and the plate 400 kept stationary.

The projection optical system 300 projects a pattern on the surface of the mask 200 illuminated with exposure light from the illumination optical system 120 at a predetermined magnification (for example, 1/4 or 1/5) onto a plate 400 described later. Expose. The projection optical system 300
An optical system comprising only a plurality of lens elements, an optical system having a plurality of lens elements and at least one concave mirror (catadioptric optical system), a plurality of lens elements and at least one diffractive optical element such as a kinoform; , An all-mirror type optical system, or the like.
When chromatic aberration needs to be corrected, a plurality of lens elements made of glass materials having mutually different dispersion values (Abbe values) may be used, or a diffractive optical element may be configured to cause dispersion in a direction opposite to that of the lens element. I do.

In this embodiment, the projection optical system 300
Further includes an optical diaphragm device 500 arranged near the pupil plane 310. Hereinafter, the optical diaphragm device 500 will be described with reference to FIGS. Here, FIG. 1 is a partially transparent perspective view of the optical diaphragm device 500. FIG. 2 is a sectional view of the optical stop device 500 shown in FIG. FIG.
FIG. 5 is an enlarged cross-sectional view showing a relationship between a light blocking plate 510 and a block 550 shown in FIG.

The numerical aperture of the optical diaphragm device 500 is changed in order to obtain an optimum image forming performance on the plate 400. The optical diaphragm device 500 is arranged on the pupil plane 310 on the projection optical system 300, and is held by the lens barrel 30 together with the above-described optical elements. The lens barrel 30 has a track surface 32 perpendicular to an optical axis O on which a block 550 described later travels. The track surface 32 has a groove for restricting the movement of the block 550 in the radial direction of the lens barrel 30. 34 is formed parallel to the radial direction of the lens barrel 30. The orbital surface 32 has at least part of a curvature having the same shape as the curve C which is a locus of the curved object-side Fourier transform surface.

The optical diaphragm device 500 includes six light shielding plates 51.
0, the cam plate 520, the cam follower 530, and the gear 54.
0 and a block 550. As is well shown in FIGS. 1 and 2, the optical diaphragm device 500 includes
0 is disposed on the block 550 and is movable in the radial direction of the optical axis O, and has a cam follower 530 on the side facing the block 550 via the light shielding plate 510. In this embodiment, the light shielding plate 510 has the cam follower 530 and the cam groove 524 described later is formed in the cam plate 520, but this may be reversed. Further, the cam follower 530 is
10 and may be provided in a block 550 that moves in synchronization with the light blocking plate 510.

The light-shielding plates 510 form an opening that provides a predetermined amount of light by sliding with each other. Shading plate 510
In this embodiment, six light-shielding plates 510 are provided by way of example, and all the light-shielding plates 510 have the same shape. The light-shielding plate 510 is disposed substantially perpendicular to the optical axis O such that a part of the region overlaps with each other,
The tip of the light-shielding plate 510 on the optical axis O side has an arc-shaped contour. Preferably, the curvature of the arc is the same as the aperture diameter corresponding to the maximum numerical aperture required by the projection optical system 30. Accordingly, the shape of the opening formed by each light blocking plate 510 is close to a polygon having a maximum opening diameter and a polygon having a small opening diameter and the same number of corners as the number of the light blocking plates 510. It can be regarded as an aperture stop having a small aperture diameter within the range of performance.

Further, by setting the thickness (height) from the bottom surface of the lens barrel 30 to the orbital surface 32 to be different for two adjacent light shielding plates 510, the light shielding plate 510 is positioned at the center of the optical axis O. When moving in the direction, two adjacent light blocking plates 510 can be prevented from interfering with each other. The two adjacent light-shielding plates 510 may be previously subjected to a surface treatment so as to have lubricity, or may be formed with minute projections (not shown) on the surface and slid with each other with low friction. Light shield plate 51
0 is constantly urged to close by a biasing member such as a spring (not shown).

The cam plate 520 is disposed on the lens barrel 30 via a bearing (not shown), and is configured to be rotatable about the optical axis O. The cam plate 520 is an annular plate member arranged substantially in parallel with the light shielding plate 510. Cam plate 5
A cam groove 524 for determining the moving direction of each light shielding plate 510 is formed in the housing 20, and the cam groove 524 accommodates a cam follower 530 attached to each block 550. In this embodiment, the cam grooves 524 are formed in a track shape, and the six cam grooves 524 are arranged radially.
The shape is exemplary. In this embodiment, the cam groove 524 is provided on the cam plate 520, but may be formed on another member that is connected to the cam plate 520 and moves in synchronization with the cam plate 520.

The cam follower 530 functions as a mover for moving the light shielding plate 510 by moving the cam groove 524. In the present embodiment, the upper shape of the cam follower 530 is a spherical shape, but the shape is not limited to a spherical shape, and any shape is possible as long as it can move along the cam groove 524.

The gear 540 is connected to the cam plate 520,
It is connected to a driving device (not shown) outside the lens barrel 30. By driving a driving device (not shown), the gear 540 can be moved, and the cam plate 520 connected to the gear 540 can be rotated around the optical axis O. As a result, the cam plate 5
The cam follower 5 is rotated by the cam groove 524 provided in the cam follower 5.
The light-shielding plate 510 moves by a predetermined amount via 30. As another method of rotating the cam plate 520, the lever 526 provided on the cam plate 520 may be manually rotated in the circumferential direction of the optical axis O to rotate the cam plate 520 around the optical axis O. It is possible.

As shown in FIG. 3, the block 550 fixes the light shielding plate 510 and has a moving mechanism 552 on the lower surface.
The block 550 is disposed in the groove 34 in the radial direction of the lens barrel 30 formed on the track surface 32 of the lens barrel 30 via the moving mechanism 552. In the block 550, the moving mechanism 552 arranged on the lower surface moves according to the groove 34 formed in the raceway surface 32, so that the movement of the lens barrel 30 in the circumferential direction is restricted, and the block 550 can move only in the radial direction.

Referring to FIGS. 1 and 2, the operation of the optical diaphragm device 500 will be described. When a rotational movement about the optical axis O is given to the cam plate 520 by the gear 540 or the lever 526, the light shielding plate 510 fixed to the block 550 moves via the cam follower 530. On this occasion,
As described above, the moving direction of the block 550 is such that the moving mechanism 552 provided on the lower surface moves in the radial direction of the lens barrel 30 along the groove 34 formed on the raceway surface 32 of the lens barrel 30.
The direction of movement of the light shielding plate 510 also moves along the raceway surface 32 along the barrel 30.
In the radial direction. Further, since the orbital surface 32 has the same radius of curvature as the curve C which is the locus of the curved Fourier transform surface on the object side, the movement curve drawn by the optical axis O side tip of the light shielding plate 510 is the curve C Becomes That is, the optical diaphragm device 5
In the case of 00, when the size of the opening is set by the light shielding plate 510, a stop is provided at a position in the direction of the optical axis O that is optimal for the opening. At this time, the tip of the light-shielding plate 510 on the optical axis O side moves while drawing the locus of the Fourier transform plane on the object side. Therefore, in the optical diaphragm device 500, the aperture is set at the optimal position in the optical axis O direction at the same time as setting the size of the aperture while reducing the occupied space with a simple configuration, and it is possible to provide excellent imaging performance. it can.

The optical diaphragm device 500 shown in this embodiment may be used in combination with a plurality of stages as appropriate. Further, in the present embodiment, the case where the optical stop device 500 is configured as the aperture stop (NA stop) of the projection optical system 300 has been described. However, as described above, the optical stop device 500 of the present invention includes the illumination optical system 1.
The present invention can also be applied to 20 aperture stops (σ stop).

Next, an optical diaphragm device 500A, which is a modification of the optical diaphragm device 500, will be described with reference to FIGS. The optical diaphragm device 500A is different from the optical diaphragm device 500 with respect to the cam plate 560. Note that the same members as those of the optical diaphragm device 500 are denoted by the same reference numerals, and redundant description will be omitted. Here, FIG. 4 shows an optical diaphragm device 5 which is a modification of the optical diaphragm device 500 shown in FIG.
It is a partially transparent perspective view of 00A. FIG. 5 is a sectional view of the optical stop device 500A shown in FIG. FIG. 6 is an enlarged sectional view showing a V region of the optical diaphragm device 500A shown in FIG.

The optical diaphragm device 500A is composed of the optical diaphragm device 5
As in the case of 00, the numerical aperture is changed in order to obtain the optimum imaging performance on the plate 400. The optical diaphragm device 500A is arranged on the pupil plane 310 on the projection optical system 300, and is held by the lens barrel 30A together with the above-described optical elements. The lens barrel 30A
Has a cam groove 524 formed in a radial direction of the optical axis O on a fixed disk (not shown). A cam follower 530 included in the light shielding plate 510 is disposed in the cam groove 524, and enables the movement of the light shielding plate 510 in the optical axis O direction.

The optical diaphragm device 500A includes a light shielding plate 510.
, A cam plate 560, and a cam follower 530.

The cam plate 560 is disposed on the lens barrel 30A via a bearing (not shown), and is configured to be rotatable about the optical axis O. The cam plate 560 has a spiral spiral groove 562 on the upper surface, and a large gear 570 for giving rotation to the cam plate 560 on the lower surface. Referring to FIG. 6, the spiral groove 562 is formed with an arbitrary number of turns and a pitch around the optical axis O. In the present embodiment, the cross-sectional shape of the spiral groove 562 is rectangular, but the shape is exemplary and may be a semicircular shape. The height of the spiral groove 562 in the optical axis O direction at an arbitrary cross section of the optical diaphragm device 500A is
It is given by an envelope E obtained by connecting the central portions 562a of the L.62, and has the same curvature as the curve C which is the locus of the curved Fourier transform surface on the object side. FIG. 7 shows a specific example of a curve obtained by developing the spiral groove 562, where the vertical axis represents the height of the center of the spiral groove in the optical axis O direction, and the horizontal axis represents the numerical aperture of the projection optical system 30. In the figure, the curve has the same shape as the curve C,
That is, it can be seen that the trajectory of the Fourier transform plane is drawn.

FIG. 8 shows the optical stop device 500A shown in FIG.
FIG. 5 is an enlarged sectional view showing a relationship between a light blocking plate 510 and a block 550 in FIG. FIG. 8 is a cross-sectional view related to a cross section perpendicular to a plane on which the light shielding plate 510 can move. As shown in the figure, the block 550 fixes the light blocking plate 510, and the moving mechanism 552 on the lower surface of the block 550 is arranged in the spiral groove 562. The height of the block 550 in the direction of the optical axis O at which the light shielding plate 510 is fixed is set such that the two light shielding plates 510 have a space that does not interfere with each other and that the light shielding plate 510 is substantially in the same plane. Is different.

Referring to FIGS. 4 and 8, by rotating a small gear (not shown) outside the lens barrel 30A, the large gear 570 is moved, and the cam plate 560 connected to the large gear 570 on the lower surface is lighted. Rotate around axis O. As a result, the fixed light blocking plate 510 of the block 550 moves in the radial direction of the optical axis O via the cam follower 530. At this time, the moving direction of the block 550 is such that the moving mechanism 552 provided on the lower surface has a spiral groove 562 formed on the upper surface of the cam plate 560.
Move along the optical axis O of the light-shielding plate 510 has the same shape as the envelope E.

As described above, the envelope E has the same curvature as the curve C which is the locus of the Fourier transform surface of the curved object surface. When the size of the opening is set, a stop can be formed at a position in the direction of the optical axis O that is optimal for the opening. Further, the optical diaphragm device 500 is compared with the optical diaphragm device 500.
A is that, by making the groove in which the block 550 moves into a spiral shape, the movement gradient of the block 550 becomes gentler, and the light shielding plate 510 that forms the opening also moves with the spiral, so that a smoother operation and high-precision opening can be achieved. Positioning can be done.

Referring again to FIG. 9, the plate 400 is an object to be processed such as a wafer or a liquid crystal substrate, and is coated with a photoresist. The photoresist application step includes a pretreatment, an adhesion improver application process, a photoresist application process, and a pre-bake process. Pretreatment includes washing, drying and the like. The adhesion improver application treatment is a surface modification (that is, making the surface hydrophobic by applying a surfactant) treatment for improving the adhesion between the photoresist and the base, and the HMDS (He
An organic film such as xamethyl-disilazane) is coated or steamed. Prebaking is a baking (firing) step, but is softer than that after the phenomenon, and removes the solvent.

The plate 400 is supported by a second stage (not shown) (sometimes called a “wafer stage”). Since the second stage can apply any structure known in the art, detailed description of the structure and operation will be omitted here. For example, the second stage moves the plate 400 using a linear motor. The mask 200 and the plate 400 are scanned, for example, synchronously, and the positions of the first and second stages are monitored by, for example, a laser interferometer, and both are driven at a constant speed ratio. The second stage is provided on a stage base supported on a floor or the like via a damper, for example.

In the exposure, the light beam emitted from the laser 112 is incident on the illumination optical system 120 after its beam shape is shaped into a desired one by the beam shaping system 114. Next, the illumination light is introduced into the optical integrator 130 and is made uniform. After that, the uniformized illumination light illuminates the mask 200 through the aperture stop 140 and the condenser lens 150.

Light that passes through the mask 200 and reflects the mask pattern is imaged on the plate 400 by the projection optical system 300. Either or both of the illumination optical system 120 and the projection optical system 300 used by the exposure apparatus 1 include the optical stop device 500 or 200 according to the present invention, and
By opening and closing, the light shielding plate 510 draws a trajectory having substantially the same shape as the Fourier transform surface on the object side, and forms a stop at a pupil position that is optimal for the numerical aperture. As a result, the optical diaphragm device 50
The 0 or 500A and the exposure apparatus 1 have a simple configuration, are excellent in operability, and can provide high imaging performance.
Therefore, the exposure apparatus 1 is a high-resolution and high-quality device (semiconductor device, LCD device, imaging device (such as CCD),
Thin-film magnetic head).

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus 1 will be described with reference to FIGS. FIG. 11 is a flowchart for explaining the manufacture of devices (semiconductor chips such as ICs and LSIs, LCDs, CCDs, and the like). Here, the manufacture of a semiconductor chip will be described as an example. In step 1 (circuit design), the circuit of the device is designed. Step 2 (mask fabrication)
A mask on which the designed circuit pattern is formed is manufactured. In step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process)
Is called a pre-process, and an actual circuit is formed on the wafer by the lithography technique of the present invention using the mask and the wafer. Step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer created in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). . In step 6 (inspection), inspections such as an operation check test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 12 is a detailed flowchart of the wafer process in Step 4 shown in FIG. Step 1
In 1 (oxidation), the surface of the wafer is oxidized. Step 12 (CVD) forms an insulating film on the surface of the wafer. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition or the like. Step 14 (ion implantation) implants ions into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the exposure apparatus 1 to expose a circuit pattern on the mask onto the wafer. Step 17 (development) develops the exposed wafer. Step 18
In (etching), portions other than the developed resist image are scraped off. Step 19 (resist stripping) removes unnecessary resist after etching. By repeating these steps, multiple circuit patterns are formed on the wafer. According to the manufacturing method of this embodiment, it is possible to manufacture a device having higher quality than before.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention.

[0062]

According to the optical diaphragm apparatus of the present invention and the exposure apparatus having the same, it is possible to provide an optical diaphragm apparatus having a simple structure and excellent in operability and imaging performance, and an exposure apparatus having the same. it can. The device manufacturing method can provide devices such as high-quality semiconductors, LCDs, CCDs, and thin-film magnetic heads.

[Brief description of the drawings]

FIG. 1 is a partially transparent perspective view of an optical diaphragm device.

FIG. 2 is a sectional view of the optical stop device shown in FIG.

FIG. 3 is an enlarged cross-sectional view showing a relationship between a light blocking plate and a block shown in FIG.

FIG. 4 is a partially transparent perspective view of an optical diaphragm device which is a modification of the optical diaphragm device shown in FIG.

5 is a cross-sectional view of the optical stop device shown in FIG.

FIG. 6 is an enlarged sectional view showing a V region of the optical diaphragm device shown in FIG.

FIG. 7 is a graph showing a relationship between a numerical aperture and a height in an optical axis direction.

FIG. 8 is a cross-sectional view related to a cross section perpendicular to a plane on which the light shielding plate is movable.

FIG. 9 is a schematic sectional view of an exposure apparatus of the present invention.

10A is a plan view of a ring-shaped aperture stop applicable to the aperture stop, and FIG. 10B is a plan view of a quadrupole aperture stop applicable to the aperture stop.

FIG. 11 is a flowchart for explaining the manufacture of devices (semiconductor chips such as IC and LSI, LCDs, CCDs, and the like).

FIG. 12 is a detailed flowchart of a wafer process in Step 4 shown in FIG. 11;

[Explanation of symbols]

 EXPLANATION OF REFERENCE NUMERALS 1 exposure apparatus 30 lens barrel 100 illumination apparatus 110 light source unit 120 illumination optical system 200 mask 300 projection optical system 310 pupil plane 400 plate 500 optical stop device 510 light shielding plate 520 cam plate 530 cam follower 532 cam groove 550 block 552 moving mechanism

Claims (11)

[Claims] 1. A plurality of substantially flat light-shielding plates movably provided to variably form an opening, a track surface having a predetermined curvature in an optical axis direction, and A moving mechanism that is mounted and connected to the light shielding plate and that can move on the track surface, and that the position and size of the opening are determined by moving the moving element. Characteristic optical diaphragm device. 2. The optical diaphragm device according to claim 1, wherein the curvature is a curvature of a Fourier transform plane of an object plane. 3. The optical diaphragm device according to claim 1, wherein a locus drawn by the position of the opening has substantially the same shape as at least a part of a Fourier transform plane of an object plane. 4. The optical aperture device according to claim 1, wherein the moving mechanism further includes a substrate having a spiral groove for determining a moving path of the moving element. 5. The orbital surface is a helical surface centered on the optical axis, and in a cross section including the optical axis, an envelope of the helical surface has at least partly substantially the same shape as a Fourier transform surface of an object surface. The optical diaphragm device according to claim 1, wherein: 6. The optical aperture device according to claim 5, wherein the moving mechanism further includes a substrate having a groove formed in a radial direction for determining a moving path of the moving element. 7. A projection, comprising: the optical aperture device according to claim 1; and projecting a pattern formed on a mask or a reticle onto an object to be processed through the opening of the optical aperture device. An exposure apparatus having an optical system. 8. An illumination optical system, comprising: the optical aperture device according to claim 1; and an illumination optical system that illuminates a mask or a reticle on which a pattern is formed, through the opening of the optical aperture device. Exposure equipment. 9. A step of determining an aperture and a position in an optical axis direction of the projection optical system using a projection optical system provided with the optical stop device according to claim 1; Projecting the pattern formed on the mask onto the object using the projection optical system. 10. A device manufacturing method comprising: a step of projecting and exposing an object to be processed by using the exposure apparatus according to claim 7; and a step of performing a predetermined process on the object to be exposed and projected. . 11. A device manufactured from the object subjected to projection exposure using the exposure apparatus according to claim 7. Description: