JPH06177008A - Projection aligner - Google Patents

Abstract

PURPOSE:To realize the long service-life of a blind filter and improve an exposing throughput when resolution or focusing depth is not necessistated by applying a master drawing substrate with obliquely incident illumination to expose it to a minimum as necessary with high resolution and large focusing depth while placing a pupil filter at a projection lens aperture diaphragm position and exposing it by replacing the pupil filter with only the aperture diaphragm when the resolution or focusing depth is not necessitated so much. CONSTITUTION:A projection lens 11 is provided with carrying in/out mechnism 26 including a carriage 32 where at least either of an aperture limiting plate having a specified optical thickness and light transmissivity or a pupil filter 25 that is provided with a thin film for adjusting transmissivity and has the same optical thickness as that of the aperture limiting plate is prepared thereon, and the aperture limiting plate or the filter 25 is selectively shifted to an aperture diaphragm position of the lens 11 by means of the carriage 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus for projecting and transferring a fine pattern of a semiconductor integrated circuit or the like on an original substrate onto a substrate to be exposed such as a semiconductor.

[0002]

2. Description of the Related Art A projection exposure method using short-wavelength visible light or far-ultraviolet rays is used for forming a fine pattern of a semiconductor integrated circuit or the like on a substrate to be exposed such as a semiconductor wafer easily, at high speed and at low cost. ing. FIG. 12 shows an optical system of a conventional projection exposure apparatus described in “LSI Design and Manufacturing Technology”, page 248, published by Denki Shoin Co., Ltd. This will be roughly described with reference to FIG. 1. Light emitted from the mercury lamp 1 is condensed by the elliptic concave mirror 2 and the collimator lens 3, passes through the filter 4 for monochromaticity, and enters the fly-eye lens 5. A first reflecting mirror 6 is provided between the mercury lamp 1 and the collimator lens 3 to convert light from the lamp into a direction substantially orthogonal to the light source optical axis and to transmit heat rays to the back side. The fly-eye lens 5 is composed of an assembly of many small-diameter lenses, and the light emitted from each lens is reflected by the second reflecting mirror 7 and condensed by the condenser lens 8 to form a reticle which is an original substrate. 9 is illuminated, which can increase the uniformity of illumination. The mercury lamp 1 is the original light source (primary light source), whereas the exit side of the fly-eye lens 5 serves as a substantial emission source of the light that illuminates the reticle 9, and is called a secondary light source. The second reflecting mirror 7 is for changing the direction of the light ray again. The reticle 9 is provided on a reticle holding table 10 on which a pattern of a fine pattern such as a semiconductor integrated circuit is formed, and when illuminated by the light emitted from the condenser lens system 8, the fine pattern is projected onto the projection lens 11. Is transferred onto the wafer 12, which is a substrate to be exposed, coated with a resist. The projection lens 11 is made by combining a large number of lenses in order to eliminate various aberrations, but basically it is composed of lens groups 11a and 11b on the reticle 9 side and the wafer 12 side, and an aperture stop between them. 13 are installed. Light emitted from an arbitrary point on the reticle 9 is transmitted through the lens group 11a on the reticle 9 side and then becomes substantially parallel to the aperture stop 1.
3 and enters the lens group 11b on the wafer 12 side. After that, the light is focused by the lens group 11b on the wafer 12 side, and focused and imaged at one point at the resist position on the surface of the wafer 12. The wafer 12 has an X movement stage 14 for adjusting and determining the position and the height with respect to the projection lens 11.
It is installed on the Y moving stage 15, the Z moving stage 16, and the rotating stage 17. The resolution of the pattern transferred onto the wafer 12 is determined by whether or not the diffracted light by the pattern existing on the reticle 9 can be taken into the aperture stop 13, and the highest resolution is 0 from the pattern on the reticle 9.
It is generally determined whether the second-order diffracted light and the first-order diffracted light can be taken into the aperture stop 13. The direction in which the first-order and higher-order diffracted light travels is determined by the cycle of the pattern and the fineness of the pattern. Therefore, when the reticle 9 is vertically illuminated, the projection lens 1 with a fine pattern
The diffracted light of the first order or more advances in the outward direction of 1. Therefore, the larger the aperture of the aperture stop 13, the more diffracted light having a fine pattern can be captured, resulting in high resolution.

By the way, Japanese Patent Application Nos. 3-99822 and 3-157401 already filed by the same applicant.
For example, the reticle is obliquely illuminated so that the 0th-order diffracted light of the pattern existing on the reticle passes near the outer periphery of the aperture stop in the oblique illumination light traveling direction, and the 1st-order diffracted light on one side is opposite to the aperture stop. If the light passes through the outer periphery of the reticle, the reticle is illuminated vertically, and the first-order diffracted light on both sides of the pattern existing on the reticle passes through the aperture stop, compared to the direction of the incident light. It is disclosed that a very high resolution can be obtained because even the first-order diffracted light that spreads outward at an angle of about twice can be captured. In addition, when the method of illuminating the reticle obliquely is adopted as described above, a transfer image is formed only by the 0th-order diffracted light and the 1st-order diffracted light on one side. There is an advantage that the depth of focus at the time of transferring a fine pattern is significantly improved as compared with the case of a total of three light fluxes of the first-order diffracted light. In order to illuminate the reticle obliquely, as disclosed in Japanese Patent Application No. 59-212169, the light from the center of the fly-eye lens 5 on the exit side is cut off and the light from the periphery is illuminated. Good. That is,
Illumination may be performed by an annular or multipoint secondary light source. However, if the reticle 9 is simply illuminated at an angle, the reticle 9
The 1st-order diffracted light due to the pattern depending on the above can be taken into the aperture stop only for one side, whereas the 0-th order diffracted light that travels straight passes through the aperture stop. As a result, the 0th-order diffracted light becomes too much, and the contrast of the image of the fine pattern formed at the resist position decreases. For the purpose of compensating for this drawback, Japanese Patent Application Nos. 3-135317 and 3-157401, etc., adjust the amount of 0th-order diffracted light to an appropriate amount at the time of oblique illumination. Disclosed is a projection exposure apparatus and method having "a projection lens aperture whose transmittance is adjusted around the aperture".

[0004]

However, the aperture stop 1
When the "pupil filter", which is the "projection lens aperture whose transmittance is adjusted", is installed at the position of 3, the resolution becomes high and the depth of focus becomes deep, but the following problems occur. The exposure light passing through the projection lens and reaching the substrate to be exposed is reduced by the amount that the transmittance is limited by the pupil filter. Therefore, the exposure time increases correspondingly, and the throughput decreases. The light that is limited by the pupil filter and cannot pass through the aperture stop position is either absorbed by the pupil filter or reflected by the pupil filter, depending on the type of the pupil filter.
The reflected light will eventually be absorbed somewhere inside the projection lens, or will be reflected several times somewhere and then will pass through the aperture stop of the projection lens again and reach the substrate to be exposed. When absorbed by the pupil filter, the absorbed energy is converted into heat, causing the temperature of the pupil filter to rise. If it is absorbed somewhere inside the projection lens, it causes a temperature rise in that part. If the temperature rises anywhere in the projection lens, including the pupil filter, the projection lens will be distorted and the lens dimensions and interlens dimensions will change. It causes dimensional changes and deterioration of uniformity in the exposure field. Also,
When a projection lens with a pupil filter is used for a long time, the thin film forming the pupil filter deteriorates due to long-time irradiation of exposure light rays, and eventually the film peels off and the peeling pieces adhere to the projection lens members above and below the filter. Since these deposits cause transfer defects during exposure, they must be carefully monitored to prevent them from depositing. However, once such peeling pieces adhere to the projection lens member, they cannot be removed unless the projection lens is disassembled and overhauled. On the other hand, when the light is reflected by the pupil filter surface, the light that reaches the pupil filter surface again after passing through the pupil filter surface after being reflected several times and then reaching the substrate to be exposed is noisy in the light rays forming the pattern. Since it is superposed as light, it causes deterioration of resolution, deterioration of exposure contrast, and the like. When a glass material with some translucency is used as a pupil filter for limiting the transmittance in a projection lens designed to be a simple aperture plate as an aperture stop, the optical path length is changed and the resolution is impaired. . When a certain glass material is used as a pupil filter for limiting the transmittance, a projection lens designed by correcting the lens aberration in consideration of the existence of the glass material must be used.

In order to deal with the above three problems,
Accordingly, when transferring a large pattern for which high resolution is not required, exposure is performed without limiting the transmittance of the aperture stop. Accordingly, the frequency of use of the pupil filter that limits the transmittance is reduced. Also, the pupil filter film is replaced before it is deteriorated and peeled off. Corresponding to the above, a projection lens which is designed by correcting the lens aberration in consideration of the existence of a glass material to be inserted as a pupil filter for limiting the transmittance in advance is used. Is effective. The method of exposing without limiting the transmissivity of the aperture stop when transferring a large pattern that does not require high resolution, as a means to solve the problem, reduces the frequency of use of the pupil filter that restricts the transmissivity. At the same time, it becomes a countermeasure against the problem.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to illuminate the original drawing substrate with oblique incidence and place a pupil filter at the projection lens aperture stop position. Extend the life of the pupil filter by performing exposure with high resolution and large depth of focus to the minimum required, and replacing the pupil filter with a simple aperture stop for exposure when resolution or depth of focus is not so required. It is an object of the present invention to provide a projection exposure apparatus capable of improving the exposure throughput when resolution and depth of focus are not required.

[0007]

To achieve the above object, a first invention is a projection exposure apparatus for projecting and transferring a pattern on an original drawing substrate onto a substrate to be exposed through a projection lens. It includes a carriage on which at least one of an aperture limiting plate having optical thickness and translucency or a thin film for transmittance adjustment is formed and at least one of pupil filters having the same optical thickness as the aperture limiting plate is installed. A carry-in / carry-out mechanism is provided, and the carriage limits the aperture limiting plate or the pupil filter at the aperture stop position of the projection lens. A second invention is a projection exposure apparatus for projecting and transferring a pattern on an original drawing substrate onto a substrate to be exposed through a projection lens, comprising a loading / unloading mechanism including a carriage on which a composite optical element is installed. The optical element has a portion having a light-shielding film that limits only the size of the opening formed in a single light-transmitting plate having a predetermined optical thickness and light-transmitting property, a transmission film that limits the transmittance, and an opening. Of the composite optical element, the carriage has a portion where a light-shielding film that limits the size of the composite optical element exists, and the carriage has a portion where the light-shielding film that limits only the size of the opening of the composite optical element exists, or A portion where the light-shielding film that limits the size is present is selectively positioned at the aperture stop position of the projection lens. Third
In a projection exposure apparatus for projecting and transferring a pattern on an original drawing substrate onto a substrate to be exposed through a projection lens, the invention comprises a loading / unloading mechanism including a carriage having a predetermined optical thickness and translucency. The carriage is formed with a portion where a light-shielding film that limits only the size of the opening is present, and a portion where a light-transmitting film that limits the transmittance and a light-shielding film that limits the size of the opening are present. Is selectively located at the aperture stop position of the projection lens, or a portion where a light-shielding film that limits only the size of the projection lens or a portion where a light-transmitting film that limits the transmittance and a light-shielding film that limits the size of the aperture exist.

[0008]

In the present invention, the projection lens used is one which is designed by correcting the lens aberration in consideration of the existence of the glass material which is put in advance as the pupil filter for limiting the transmittance.
The carry-in / carry-out mechanism carries the aperture limiting plate, the pupil filter, or the composite optical element to the aperture stop position of the projection lens by the carriage. The part where the aperture limiting plate and the light-shielding film that limits only the size of the aperture of the composite optical element are present does not limit the transmittance of the aperture stop and is used when transferring a large pattern that does not require high resolution. , Reduce the frequency of use of the pupil filter that limits the transmittance. The portion in which the pupil filter, the transmissive film that limits the transmittance of the composite optical element, and the light-shielding film that limits the size of the aperture are present is used when performing exposure with high resolution and large depth of focus. The carriage having a predetermined optical thickness and translucency has a portion where a light-shielding film that limits only the size of the opening exists, a transmissive film that limits the transmittance, and a light-shielding film that limits the size of the opening. By forming the portion to be formed, an aperture limiting plate / pupil filter is configured.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 1 is a perspective view of a projection lens and a loading / unloading mechanism, and FIGS. 2A, 2B, and 2C are views showing a positioning and fixing structure of an aperture limiting plate or a pupil filter, respectively.
In the figure, the same components as those of the conventional device shown in FIG. 12 are designated by the same reference numerals. In these figures, the projection lens 11 arranged between the reticle and the wafer which is the substrate to be exposed to form a fine pattern of the reticle on the wafer is a reticle side lens group 11a (FIG. 12).
And a wafer-side lens group 11b (FIG. 12) are coaxially built in. The lens group 11a on the reticle side and the lens group 11 on the wafer side are formed on part of the peripheral surface of the cylindrical body 22.
In the portion corresponding to b, that is, at the position where the aperture stop is installed, an opening 23 that is long in the circumferential direction is formed, and the opening 23 has a light-transmitting property and does not limit the transmittance without limiting the transmittance. An aperture limiting plate 24 that limits only the size {FIG. 3
(A)} or a loading / unloading mechanism 26 for selectively inserting and installing a pupil filter 25 having the same optical thickness as the aperture limiting plate 24 and limiting the transmittance at the aperture stop position of the projection lens 11. It is arranged. In this case, the projection lens 11
Is used in which the lens aberration is corrected and designed in consideration of the existence of the glass material of the pupil filter 25 which limits the transmittance in advance. The aperture limiting plate 24 is used when transferring a large pattern for which high resolution is not required, and is used by the pupil filter 25.
Is used when exposure with high resolution and large depth of focus is performed.

The aperture limiting plate 24 is made of a transparent glass material such as synthetic quartz, fused quartz, synthetic fluorite, fused fluorite, etc., and has a surface center as shown in FIG. 3 (a). The surface other than the opening portion (light transmitting portion) 24a of the light shielding film 27
Is covered by. It goes without saying that the light shielding film 27 may be made of any material as long as it shields the exposure light beam.

As shown in FIGS. 3B to 3J, the pupil filter 25 is made of a glass material similar to that of the aperture limiting plate 24 and has a light-transmitting plane plate 28, and is formed on the plane plate 28. Light-shielding film 27 and transmissive film 29 for adjusting transmittance
It consists of and. The transmissive film 29 may be made of any material as long as it can impart a predetermined transmittance to the exposure light beam, and is, for example, a thin film of chromium, a thin film of chromium oxide, a multilayer thin film of magnesium fluoride and zinc sulfide, or the like. Note that FIG.
The pupil filters 25 of (b) to (j) will be described later.

Here, the aperture limiting plate 24 and the pupil filter 2
The optical thickness of 5 does not mean the absolute value of these simple thicknesses, but means the thickness considering the refractive indexes of the aperture limiting plate 24 and the plane plate 28. The total phase angle Φ (radian) that changes while the light beam of wavelength λ passes through the entire thickness including the adhesion film is 2
The value obtained by dividing by π and multiplying by the wavelength λ is the optical thickness t (= Φ · λ / 2π) here. Although the expression "the transmittance is not limited" is used in the above description, a slight attenuation of the transmission amount is inevitable with any aperture limiting plate 24 or flat plate 28 made of any glass material. It means that the transmittance is not lowered. The same applies to the following description.

In FIG. 1, the loading / unloading mechanism 26 is installed on the upper surface of an inverted L-shaped base 30 fixed to the outer peripheral surface of the tubular body 22, and one end thereof is inserted into the tubular body 22 through the opening 23. The guide member 31 is provided, and the guide member 31
The aperture limiting plate 24 or the pupil filter 25 to the aperture 23
The carriage 32, which is inserted into the projection lens 11 and installed at the aperture stop position, is a cross roller guide 33 (33a to 33a).
It is slidably disposed via d). Further, a motor 35 is arranged on one side surface of the guide member 31 via a mounting plate 36, and the rotation of the motor 35 causes the output shaft 3 to rotate.
7 is transmitted to the carriage 32 via a gear 38 attached to the carriage 7 and a rack 39 formed on the upper surface of the carriage 32, whereby the carriage 32 linearly reciprocates into the aperture limiting plate 24 or the projection lens 11 of the pupil filter 25. Can be inserted and carried out from the projection lens 11. In order to stop the carriage 32 at a predetermined position so that the aperture limiting plate 24 or the pupil filter 25 is properly installed at the aperture stop position on the optical axis of the projection lens 11, the rotation angle of a pulse motor or a motor with an encoder is changed. The carriage 32 is driven and controlled by a motor 35 that can detect or control the movement amount of the carriage 32.
Or the position of the carriage 32 or the aperture limiting plate 24 or the pupil filter 25 is detected or measured by some means so that the carriage 32, the aperture limiting plate 24 or the pupil filter 25 comes to a predetermined position. A servo mechanism that gives a command to the drive system of the carriage 32 may be used. Further, when the carriage 32 is manually moved, a notch may be provided at an arbitrary position of the carriage 32, and the carriage 32 may be stopped at a position where a ball fits in the notch by a spring.
The carriage 32 is formed in a plate-like shape that is long in the moving direction, so that a plurality of aperture limiting plates 24 and / or pupil filters 25 can be installed in the longitudinal direction. As shown, the aperture 41 and the aperture limiting plate 24 or the pupil filter 2 through which the exposure light beam passes.
Appropriate means for fixing 5 are provided. In this way, a plurality of aperture limiting plates 24 or pupil filters 25
By setting the position of the carriage 32, the aperture limiting plate 24 or the pupil filter 25 can be replaced only by changing the position of the carriage 32, and the exposure can be performed under the optimum aperture condition according to the type of pattern. You can That is, for example, when high resolution and large depth of focus are required,
As oblique illumination, a pupil filter 25 corresponding to the shape of the secondary light source for illumination is installed at the aperture stop position for exposure, and when direct exposure of a large pattern in which resolution and depth of focus are not so important, normal direct incident light is used. As the illumination to be included, the exposure may be performed by moving and setting the aperture limiting plate 24, which adjusts only the size of the aperture, to the aperture stop position.

As shown in FIG. 2, as a method for installing and fixing the aperture limiting plate 24 or the pupil filter 25 on the carriage 32, vacuum suction (a), pressing by a spring (b), screwing by a holding metal fitting (c), Adhesion or the like may be optional. 2A, a vacuum suction groove (or vacuum suction hole) 42 and a positioning pin 43 are provided on the upper surface of the carriage 32.
An example in which the air in the vacuum suction groove 42 is exhausted and the aperture limiting plate 24 or the pupil filter 25 is suction-fixed to the upper surface of the carriage 32. In the same figure (b), a positioning pin 43 and one end of the carriage 32 are attached to the carriage 32. Fixed leaf spring 45
An example in which the aperture limiting plate 24 or the pupil filter 25 is positioned and fixed by means of the above, in the same figure (c), the holding metal fitting 47 is fitted to the step portion 32a provided on the upper surface of the carriage 32 and fixed by the set screw 46. The aperture limiting plate 24 or the pupil filter 25 is fixed by 47 via a packing 48. In this case, the holding metal fitting 47 is uniquely positioned with respect to the carriage 32, and the aperture limiting plate 24 or the pupil filter 25 is fitted into the holding metal fitting 47 to be uniquely positioned with respect to the holding metal fitting 47. It A reference surface is provided on the carriage 32, and the aperture limiting plate 24 or the pupil filter 2 having a predetermined optical thickness.
Make sure that 5 can be installed without tilting to a predetermined height. When adhering, the aperture limiting plate 24 that has been adhered once
Alternatively, the pupil filter 25 cannot be easily changed, but there is an advantage that the pupil filter 25 can be easily changed in the case of the above-mentioned vacuum suction, pressing by a spring, fixing by screwing with a pressing metal fitting, or the like. Therefore, since many aperture limiting plates 24 or pupil filters 25 are attached, it is not necessary to make the carriage 32 extremely long. In an extreme case, either the aperture limiting plate 24 or the pupil filter 25 can be installed on the carriage 32. It may be one. If the carriage 32 does not need to be extremely long, the accuracy of the transport mechanism of the carriage 32 can be easily obtained, and the aperture limiting plate 24 can be placed at the aperture stop position of the projection lens 11.
Alternatively, the accuracy and reproducibility of the position where the pupil filter 25 is installed are improved. Further, even when either the aperture limiting plate 24 or the pupil filter 25 can be installed, the aperture limiting plate 24 or the pupil filter 25 installed on the carriage 32 must be replaced for each replacement. On the other hand, since the carriage 32 is put out of the cylindrical body 22 for replacement, the carriage 32 can be replaced more stably, easily and accurately than when the carriage 32 is replaced directly at an invisible position in the projection lens 11. There are advantages.

FIGS. 3A to 3J are perspective views showing the aperture limiting plate and various pupil filters. The figure (a) shows the aperture limiting plate 24 which simply limits the size of the aperture. Since the aperture limiting plate 24 is as described above, the description is omitted. Figures (b) to (j) show various pupil filters, and Figure (b) shows an annular transmission film 29 in the opening 25a.
(C) is an example in which a multi-point transmissive film 29 is provided in the opening 25a, and (d) is a transmission having different transmittances T ₁ and T _{2 in} the opening 25a. An example in which the membranes 29a and 29b are concentrically provided, (e) shows that the permeable membrane 29a having the transmittance T ₁ is provided in a multipoint manner in the opening 25a, and the permeable membrane having the transmittance T ₂ is also provided outside thereof. An example in which 29b is provided in an annular shape,
(F) The figure shows a multi-point permeable membrane 29a in the opening 25a.
(Transmittance T ₁ ) is provided, and the permeable film 29 is provided outside of
b (transmittance T ₂ ) is provided, (g) is an example in which a transmissive film 29c having a transmittance T ₃ is provided in the center of (d),
(H) is an example in which a transmissive film 29c having a transmittance T ₃ is also provided in the central part of (e), and (i) is a transmissive film 29c having a transmissivity T ₃ in the central part of (f). FIG. 9 (j) is an example in which a transmissive film 29 is provided so that the transmittance T can be changed arbitrarily continuously as shown in FIG. In the figure, the portion with the light shielding film 27 is hatched, and the transmission film 29
The part with (29a to 29c), that is, the part where the transmittance is intentionally reduced is shown by hatching or cross-hatching.

The shape of the transmission film 29 of the pupil filter 25 is determined according to the shape of the fly-eye lens exit, that is, the shape of the secondary light source. The projection optical system is configured so that the fly-eye lens exit port forms an image at the aperture stop position of the projection lens 11. Therefore, when the fly-eye lens exit is annular, the annular transmittance adjuster (29) in (b) roughly matches the size of the annular image of the fly-eye lens exit. In the case of (g), the shape of the portion having the transmittance T ₁ is roughly matched with the size of the annular image at the exit of the fly-eye lens. Of course, it goes without saying that they may be perfectly matched. Even when the fly-eye lens exit has a multipoint shape, a pupil filter provided with a transmission film may be used according to the number, size, and position of the image points.
That is, the multi-point transmissive film 29 in (c) is roughly or completely adjusted to the size of the multi-point image at the exit of the fly-eye lens. Also in the cases of (e), (f), (h), and (i), the shape of the portion having the transmittance T ₁ is roughly or completely set to the size of the multipoint image at the exit of the fly-eye lens. To match. If the shape of the fly-eye lens exit is multi-point,
You may use the pupil filter like (b), (d), (g) which has a ring-shaped transmission film which envelops the multipoint image which can be made in the aperture stop position. Further, the shape and dimensions of the aperture limiting plate 24 and the pupil filter 25 are arbitrary, and they do not have to be disc-shaped as shown in FIGS. 1 and 3. The size of the aperture stop and the convenience of mounting at the aperture stop position, the light-shielding film 27 and the transmission film 2
The shape and dimensions may be determined by comprehensively considering the manufacturing convenience of item 9. The transmittance of the pupil filter 25 is arbitrary, and as a special case, T ₁ = T ₂ , T ₂ = T ₃ , T ₁ = T ₃ ,
Conditions such as T ₁ = T ₂ = T ₃ are also possible.

FIG. 4 is a perspective view showing a composite optical element in which an aperture limiting plate and a pupil filter are integrated. In this embodiment, instead of installing a plurality of aperture limiting plates 24 or pupil filters 25 on the carriage 32, only the size of the aperture is set on the elongated translucent plate 50 made of one glass material. A light-shielding film 27 that serves as a diaphragm for adjustment and a transparent film 2 for adjusting the transmittance
By forming a plurality of 9 in the longitudinal direction, the aperture limiting plate and the pupil filter are integrated to form the composite optical element 51. Other configurations are the same as those in the above embodiment. Also,
The composite optical element 51 having a plurality of such light-transmitting films 29 and light-shielding films 27 serving as diaphragms for adjusting only the size of the aperture.
A plurality of carriages may be mounted on the carriage 32 or may be exchangeable. Naturally, in preparation for deterioration of the permeable membrane 29,
You may use the composite optical element which has the part with the same transparent film in multiple places.

By the way, only by moving the carriage 32 to a predetermined position, the surface of the aperture limiting plate 24, the pupil filter 25 or the composite optical element 51 which becomes a diaphragm for adjusting only the size of the transmissive film or the aperture is formed. , The traveling direction of the carriage 32 is set so that the optical axis direction of the lens group in the projection lens 11 is perpendicular to the range in which the aberration falls within the allowable range.
It is not always easy to make adjustments with respect to the optical axis direction of the inner lens group. Therefore, with the aperture limiting plate 24, the pupil filter 25 or the composite optical element 51 on the carriage 32 inserted in the aperture stop position in the projection lens 11,
The surface of the aperture limiting plate 24, the pupil filter 25 or the transmissive film of the composite optical element 51, or the surface of the portion which serves as a diaphragm for adjusting only the size of the aperture, has an aberration with respect to the optical axis direction of the lens group in the projection lens 11. It is vertical within the allowable range, and
The position of the projection lens optical axis in the plane of the aperture limiting plate 24, the pupil filter 25 or the transmissive film of the composite optical element 51, or the surface of the part that serves as the diaphragm for adjusting only the size of the aperture is set to the original aperture diaphragm position. It suffices to separately provide a means for adjusting so that the predetermined position is matched. For example, the guide member 31 that guides the carriage 32 may be finely moved in the optical axis direction of the projection lens and the tilt angle with the optical axis of the projection lens may be adjusted.

FIG. 5 is a perspective view showing an embodiment in which the inclination angle of the carriage and the position in the optical axis direction of the projection lens can be adjusted. The guide member 31 is pressed against the base 30 by the spring 54, and the upper surface of the guide member 31 is located at three points A, B, and C.
Are adjusted in the optical axis direction of the projection lens by the respective micrometer heads (or differential micrometer heads) 55, thereby adjusting the inclination of the guide member 31, in other words, the carriage 32. By doing so, the position of the aperture limiting plate, the pupil filter or the composite optical element 51 installed on the carriage 32 in the projection lens optical axis direction and the tilt angle with respect to the projection lens optical axis can be accurately adjusted. Although a coil spring is used as the spring 54 in the drawing, it may have any shape,
It is more preferable if the base 30 and the guide member 31 are spring-like parts that also serve as guides that move only in the direction of the optical axis of the projection lens except for the range of slight inclination.

FIG. 6 is a cross-sectional view of a main part showing still another embodiment of the present invention. In this embodiment, the guide member 31 is replaced by the leaf spring 6.
An example in which it is elastically held by 0 is shown. 61,6 in the figure
Reference numeral 2 is a spring retainer plate and bolt for fixing the leaf spring 60 to the base 30 and the guide member 31, and 63 is a nut.
Other configurations are substantially the same as those of the embodiment shown in FIG. In this case, since the leaf spring 60 also serves to fix the base 30 and the guide member 31, the spring 54 and the screw 5 shown in FIG.
6, the washer 57 and the like are unnecessary. Micrometer head 5
Although 5 has a spherical tip in the figure, a flat tip is used, and a conical hole is provided on the base 30 side to insert a steel ball or a gem ball, and the base 30 is inserted through these. And guide member 3
The gap with 1 may be adjusted.

In FIG. 7, the guide member 31 is movably held in the vertical direction by the bellows-like component 70, and the height and inclination of the guide member 31 are adjusted by the micrometer head 55. The bellows-shaped component 70 is easily bent only in the optical axis of the projection lens and has high rigidity in a direction perpendicular to the optical axis of the projection lens.
A bellows-like component as disclosed in 60302 is used. The position and the number of the bellows-shaped component 70 attached are arbitrary. In order to save space, the tip of the micrometer head 55 may be placed in the central hollow portion 71 of the bellows-shaped component 70. Guide member 31
Since the amount of movement of the micrometer head 55 is small, if fine movement resolution cannot be obtained by linearly driving the micrometer head 55, between the tip of the micrometer head 55 and the base 30 for mounting the guide member 31, A spring having a smaller spring constant than the spring 54 shown in FIG. 5, the leaf spring 60 shown in FIG. 6, and the bellows-like component 70 shown in FIG. 7 may be interposed. When the micrometer head 55 presses the spring having a small spring constant, the micrometer head 55 moves in accordance with the ratio of the spring constant of the spring having a small spring constant and the spring pressing the guide member 31 to the base 30. Of the spring 54, leaf spring 60 or bellows-like component 70
Bends, and the gap between the guide member 31 and the base 30 can be finely adjusted.

At this time, the aperture limiting plate, the pupil filter or the composite optical element determines whether the position of the aperture limiting plate, the pupil filter or the composite optical element in the projection lens optical axis direction and the inclination angle with the projection lens optical axis are correct. It can be determined by detecting the position of the surface in the optical axis direction of the projection lens at three or more points above. For example, an optical system in which a mark is formed on the surface of the aperture limiting plate, the pupil filter, or the light-shielding film or the transmission film of the composite optical element, and the microscope is observed from outside the projection lens through the projection lens at a narrow focal depth. Observed by
How much the position at which the microscope observing optical system is focused on the mark is deviated from the reference focus position of the microscope observing optical system is determined, and the position of the transparent film or the surface serving as the aperture stop is determined. At three or more mark points, if the positions in the projection lens optical axis direction of the transmissive film or the surface simply serving as the aperture stop are detected, the positions of the transmissive film and the surface simply serving as the aperture stop in the projection lens optical axis direction and The tilt angle with the projection lens optical axis can be obtained.

It is also possible to transfer the pattern by projection exposure to check how the pattern is formed. That is, the pattern or pattern cross-sectional shape that achieves a high resolution by transferring the pattern by projection exposure by appropriately changing the tilt angle with respect to the projection lens optical axis or the position in the projection lens optical axis direction of the transparent film or the surface that simply serves as the aperture stop. , The conditions for minimizing the asymmetry between the left, right, top, and bottom of the pattern, etc., and comprehensively consider the optimal transmission film and the tilt angle of the surface that is simply the aperture stop with respect to the projection lens optical axis and the projection lens optical axis direction. The position of should be decided.

FIGS. 5 to 7 show an example in which the three positions of the guide member 31 can be moved in the direction of the optical axis of the projection lens by the micrometer heads 55, but as another measure, it will be described later in FIG. 11, for example. As described above, a plurality of suitable positions on the guide member 31 are installed on the base 30 via the electrostrictive element, and a voltage is applied to the electrostrictive element to give strain, and the inclination angle of the guide member 31 and the base The distance from 30 may be adjusted.

In the above description of FIGS. 5 to 7, the rotation of the motor 35 is transmitted to the carriage 32 by the gear 38 and the rack 39 to linearly reciprocate the carriage 32. However, the present invention is not limited to this. For example, the guide member 3
1 is provided with a screw shaft along the traveling direction of the carriage 32,
The carriage 32 may be provided with a nut that is screwed onto the screw shaft, and the nut may be moved along the screw shaft by rotating the screw shaft by a motor, thereby causing the carriage 32 to make a reciprocating linear motion. Further, in order to make the driving smooth, the screw shaft may be a ball screw shaft and the nut may be a ball nut.

FIG. 8 is a perspective view showing another embodiment of the loading / unloading mechanism, and FIG. 9 is a sectional view. In this embodiment, the carriage 32
Is formed into a disc shape and attached to a rotary shaft 73, and the rotary shaft 73 is intermittently rotated by a motor 35, whereby the aperture limiting plate 24 installed on the carriage 32.
Alternatively, the pupil filter 25 is selectively moved to the aperture stop position of the projection lens 11. In addition, 74 is a lower bracket, 75 is an upper bracket, 7
6 is a bearing, 77 is a flexible shaft coupling, 78 is a bearing inner ring retainer plate,
Reference numeral 79 is a bearing outer ring pressing plate, 80 is a nut, 81 is a spacer, and 82 is a washer or packing. Other configurations are similar to those of the embodiment shown in FIG. In such a configuration, various aperture limiting plates 24 that simply adjust only the size of the apertures and various pupil filters 25 that have different transmittance and distribution conditions are installed on the carriage 32.
When 2 is rotated intermittently to move the desired aperture limiting plate 24 or pupil filter 25 to the aperture stop position of the projection lens 11, exposure can be performed under optimum aperture stop conditions depending on the type of pattern. Further, when a plurality of aperture limiting plates 24 and pupil filters 25 are installed on the carriage 32, they may be manufactured separately as shown in FIG. 8, but they are formed in a disc shape or an arc shape. A composite optical element having one transparent plate having a portion where a light-shielding film that limits the size of an opening is present, a portion where a light-transmitting film that limits the transmittance and a light-shielding film that limits the size of an aperture are present Needless to say, it may be installed.

Further, as shown in FIG. 10, the carriage 9
0 itself is formed of a glass material having a predetermined optical thickness and a light-transmitting property and transmitting an exposure light beam, and its upper surface (or back surface)
The portion 9 where the light shielding film 27 for limiting the size of the opening is present
1, the portion 92 where the transmission film 29 that limits the transmittance and the light-shielding film 27 that limits the size of the opening exist may be directly formed. In such a configuration, since the carriage 90 itself constitutes the aperture limiting plate / pupil filter, the structure is simple, and the portion 91 where the light shielding film 27 for limiting the size of the aperture and the transmittance are limited. A portion 92 in which a transparent film 29 for controlling the size and a light shielding film 27 for limiting the size of the opening are present
This has the advantage that mutual positional accuracy and perpendicularity of the respective portions with respect to the optical axis of the projection lens can be easily secured.

By the way, in the case of FIGS. 8 to 10 as well, the portion 91 in which the light shielding film 27 for limiting the size of the opening is present only by stopping the rotation of the carriage 32 or 90 to a predetermined position, and the transmittance. The surface of the portion 92 where the transmitting film 29 for limiting and the light shielding film 27 for limiting the size of the opening are present is perpendicular to the optical axis direction of the lens group in the projection lens 11 within a range where the aberration is within the allowable range. It's not always easy to do. Therefore, an arbitrary aperture limiting plate 24 on the carriage 32 or the pupil filter 25, or a portion 91 where the light shielding film 27 that limits the size of the opening of the carriage 90 exists, a transmission film 29 that limits the transmittance, and the size of the aperture. In the state where the portion 92 where the light-shielding film 27 that restricts the aperture is present is stopped at the aperture stop position, the surface that serves as a stop that limits only the size of the aperture and the surface of the filter film are the same as those of the lens group in the projection lens 11. It suffices to additionally provide means for adjusting the optical axis direction to be perpendicular to the range in which the aberration falls within the allowable range and adjusting the position in the optical axis direction to a predetermined position.

FIG. 11 is a sectional view showing still another embodiment of the carry-in / carry-out mechanism. In this embodiment, a support member 101 to which a carriage 32 and a motor 35 are attached via a lower bracket 74 and an upper bracket 75 is installed via an electrostrictive element 102 on a base 100, and an appropriate voltage is applied to the electrostrictive element 102. Is applied, the length in the optical axis direction of the projection lens is changed, and the tilt angle of the support member 101 with respect to the base 100 and the position in the optical axis direction of the projection lens are adjusted. As the electrostrictive elements 102, a plurality of, for example, three electrostrictive elements 102 are arranged at the apexes of a triangle when the projection lenses 11 are viewed from above. It is needless to say that the electrostrictive element 102 may be arranged at a larger number of positions by, for example, arranging at the apex position of the regular polygon. An electrostrictive element 102,
The method of fixing the base 100 and the support member 101 may be arbitrary. Further, similarly to the embodiment shown in FIGS. 5 to 7, the base 100 and the supporting member 101 are preliminarily pressed by a spring member, and the electrostriction is resisted against the force of the spring. The element 102 may be activated. In addition,
Other configurations are similar to those of the embodiment shown in FIGS. 8 and 9. In such a configuration, the tilt angle of the aperture limiting plate 24 and the pupil filter 25 on the carriage 32 with respect to the projection lens optical axis and the position in the projection lens optical axis direction can be adjusted with high accuracy. At this time, whether the tilt angle of the aperture limiting plate 24 or the pupil filter 25 and the position in the optical axis direction of the projection lens are correct is determined by the aperture limiting plate 24 and the pupil filter 2.
It is possible to make a determination by detecting these positions at three or more points on 5. Specifically, it may be similar to that described in the description of FIGS. It is also possible to transfer the pattern by projection exposure to see how the pattern is formed. Further, regardless of the method of using a plurality of electrostrictive elements 102 as described above, adjustment may be performed using a micrometer head as shown in FIGS. 5 to 7.

In each of the above illustrations, the light shielding film 27 for limiting the size of the opening and the transparent film 29 for limiting the transmittance are formed on the upper surfaces of the aperture limiting plate 24, the light transmitting plate 28 and the carriage 90. However, the present invention is not limited to this, and may be the lower surface side. Alternatively, the light shielding film 27 and the transmission film 29 may be sandwiched between two light transmitting plates. In any case, the light-shielding film 2 that limits only the size of the aperture of the aperture limiting plate 24, the translucent plate 28, or the carriage 90.
It goes without saying that the portion 7 and the portion of the transmissive film 29 are set to have a predetermined constant optical thickness within the allowable range of aberration. Further, the aperture limiting plate 24 may be relatively thicker than the pupil filter 25 by the optical thickness of the transmission film, and the aperture limiting plate 24 may be provided with a transmission film having the same thickness as the transmission film. Good. If the optical thickness of the transmission film of the pupil filter 25 is within an allowable range of error in consideration of lens aberration, the thickness of the light transmitting plate may be set to a predetermined constant value. In short, when the transmission film or the light-shielding film serving as a diaphragm for simply adjusting the size of the aperture comes to the original aperture stop position, the projection lens should have a normal function. It is also possible to prepare a plurality of sheets of the same type in which the dimensions and transmittance of each part of the pupil filter are changed, or a plurality of aperture limiting plates 24 in which only the aperture size for simply limiting the aperture is changed. Further, a plurality of identical pupil filters may be prepared in preparation for deterioration of the transmission film. When the carriage itself is made of a glass material having a light-transmitting property and the light-shielding film or the light-transmitting film is formed on the upper surface or the lower surface thereof, a plurality of them may be similarly formed. Further, it is effective to install the pupil filter 25 for limiting the transmittance at the aperture stop position of the projection lens when the original drawing substrate is obliquely illuminated. Therefore, the operation of inserting the aperture limiting plate 24 or the pupil filter 25 at the aperture stop position of the projection lens may be linked with the switching of the original drawing substrate illumination between the direct incident illumination and the oblique incident illumination. In the projection exposure apparatus, a plate having a transparent film portion or a hole having a circular shape, an annular shape, a multi-point shape, or the like may be arbitrarily inserted into the exit of the fly-eye lens serving as the secondary light source,
The shape of the illumination light source is made variable by sliding or rotating a plate having a plurality of emission ports. Then, when the shape of the illumination light source is automatically detected or when the information regarding the shape of the illumination light source is input from the keyboard of the control device such as the personal computer of the projection exposure apparatus, it is prepared corresponding to the shape of the illumination light source. The type of the aperture limiting plate 24 or the pupil filter 25 placed at the aperture stop position of the projection lens is displayed on the control device as an image. In this way, by the operator selecting and instructing any one of the displayed aperture limiting plate 24 or the pupil filter 25,
The corresponding aperture limiting plate 24 or pupil filter 25 can be mounted at the aperture stop position. If the shape of the illumination light source is automatically detected or key input is performed, the corresponding aperture limiting plate 24 or pupil filter 25 may be automatically attached to the aperture stop position. Alternatively, a combination of the actually effective shape and size of the illumination light source and the aperture limiting plate 24 or the pupil filter 25 mounted at the aperture stop position of the projection lens 11 is displayed on the screen of the control device, and those combinations are displayed. A combination of the shape and size of the illumination light source and the aperture limiting plate 24 or the pupil filter 25 mounted at the aperture stop position of the projection lens 11 is automatically realized by the operator selecting and instructing the combination. May be.

[0031]

As described above, according to the projection exposure apparatus of the present invention, since the loading / unloading mechanism is provided on the projection lens, the aperture has a predetermined optical thickness and a light transmitting property at the aperture stop position. Of the aperture limiting plate for limiting only the size of the aperture, and a pupil filter having a thin film for transmittance adjustment and having the same optical thickness as the aperture limiting plate, with the projection lens installed in the projection exposure apparatus. In this state, it can be selectively installed at the aperture stop position of the projection lens. Therefore, when transferring a large pattern that does not require high resolution, an aperture limiting plate can be used to reduce the frequency of use of the pupil filter used when performing exposure with high resolution and large depth of focus. it can. Therefore, the exposure throughput can be remarkably improved when the resolution and the depth of focus are not required. Further, the life of the transmission film of the pupil filter can be extended by the amount that the frequency of use of the pupil filter is reduced. Further, even if the pupil filter deteriorates, the deteriorated pupil filter can be easily replaced with the projection lens attached to the projection exposure apparatus. In the conventional device, when the pupil filter deteriorates, the projection lens needs to be removed, and in some cases, the projection lens needs to be replaced. Therefore, disassembly, reassembly, and readjustment of the entire projection exposure apparatus are required,
It took a lot of time, labor and money. According to the present invention, these problems can be solved at once. Further, the present invention can be applied to a projection exposure apparatus using a mercury lamp as a light source and a projection exposure apparatus using an arbitrary light source such as an excimer laser as an exposure light source. When an excimer laser is used as a light source, exposure energy is applied in a pulsed manner, so that the pupil filter is repeatedly subjected to a large amount of energy, and deterioration of the pupil filter causes a projection exposure apparatus using a mercury lamp as a light source. Faster than. Therefore, the present invention is particularly effective.
Further, according to the present invention, the carriage of the carry-in / carry-out mechanism is formed of a material having a predetermined optical thickness and a light-transmitting property, and this carriage has a light-shielding film that simply limits the size of the opening and a transmittance. The structure where the transmission film for limiting and the light shielding film for limiting the size of the aperture are provided is simple, and the positional accuracy between these two parts and the high perpendicularity to the optical axis of the projection lens are easy. Can be secured.

[Brief description of drawings]

FIG. 1 is a perspective view of a projection lens and a loading / unloading mechanism.

2A, 2B, and 2C are cross-sectional views showing a positioning and fixing structure of an open limiting plate or a pupil filter, respectively.

3A to 3J are perspective views of an aperture limiting plate and a pupil filter, respectively.

FIG. 4 is a perspective view showing another embodiment of the loading / unloading mechanism.

FIG. 5 is a perspective view showing still another embodiment of the loading / unloading mechanism.

FIG. 6 is a cross-sectional view showing a support structure for a guide member.

FIG. 7 is a cross-sectional view showing another embodiment of the guide member support structure.

FIG. 8 is a perspective view showing still another embodiment of the loading / unloading mechanism.

FIG. 9 is a sectional view of the loading / unloading mechanism.

FIG. 10 is a sectional view showing still another embodiment of the carry-in / carry-out mechanism.

FIG. 11 is a cross-sectional view showing still another embodiment of the loading / unloading mechanism.

FIG. 12 is a diagram showing an optical system of a conventional general projection exposure apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mercury lamp 9 Reticle 11 Projection lens 12 Wafer 13 Aperture stop 24 Aperture limiting plate 25 Pupil filter 26 Carry-in / out mechanism 27 Light-shielding film 29 Transmission film 32 Carriage 50 Translucent plate 51 Composite optical element 90 Carriage

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03F 7/20 521 9122-2H

Claims (3)

[Claims] 1. A projection exposure apparatus for projecting and transferring a pattern on an original substrate onto a substrate to be exposed through a projection lens, wherein an aperture limiting plate having a predetermined optical thickness and translucency or transmittance adjustment. A loading / unloading mechanism including a carriage on which a thin film for use is formed and at least one of pupil filters having the same optical thickness as the aperture limiting plate is installed, and the carriage limits the aperture limiting plate or the pupil filter. A projection exposure apparatus, which is installed at an aperture stop position of the projection lens. 2. A projection exposure apparatus for projecting and transferring a pattern on an original substrate onto a substrate to be exposed through a projection lens, comprising a carry-in / out mechanism including a carriage on which a composite optical element is installed. The element has a portion with a light-shielding film that limits only the size of the opening formed in a single translucent plate having a predetermined optical thickness and translucency, a transmissive film that limits the transmittance, and an opening. The carriage has a portion where a light-shielding film that limits the size thereof is present, and the carriage has a portion where the light-shielding film that limits only the size of the aperture of the composite optical element exists or the size of the transmissive film and the aperture that limits the transmittance. A projection exposure apparatus, wherein a portion where a light-shielding film for limiting the depth is present is selectively positioned at the aperture stop position of the projection lens. 3. A loading / unloading mechanism including a carriage having a predetermined optical thickness and translucency in a projection exposure apparatus for projecting and transferring a pattern on an original substrate onto a substrate to be exposed through a projection lens. The carriage is provided with a portion having a light-shielding film that limits only the size of the opening, a portion having a light-transmitting film that limits the transmittance and a light-shielding film that limits the size of the opening. A portion where a light-shielding film that limits only the size of the aperture exists or a portion where a light-transmitting film that limits the transmittance and a light-shielding film that limits the size of the aperture exist are selectively positioned at the aperture stop position of the projection lens. A projection exposure apparatus characterized by the above.