JP2005172877A - Method for forming resist pattern, method for manufacturing optical element, method for manufacturing substrate, optical element and exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a resist pattern with high accuracy and yield. <P>SOLUTION: A resist 2 on a substrate 1 is irradiated with a light through a gray scale mask 3 (b). The thus exposed resist 2 is developed to form a pattern of a microlens array in the resist 2, as shown in (c). The exposure quantity and development period to obtain the aimed figure of the microlens are determined in this steps, and then the developing time is controlled to be shorter than the developing time, to obtain the aimed figure of the microlens. The exposure period is controlled to the period to obtain the targeted figure of the microlens. The curvature of the resist pattern is therefore smaller than the curvature of the aimed resist pattern. Then the resist is re-developed for a development period, determined according to the difference between the real value and the aimed value of the resist pattern. Thus, a figure of the resist, almost equal to the targeted pattern figure, is obtained (d). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for forming a resist pattern by lithography using a gray scale mask, a method for manufacturing an optical element and a substrate, an optical element manufactured by this method, and an exposure apparatus using this optical element.

  Optical elements such as microlenses have been put into practical use mainly in the fields of digital cameras, optical communications, and MEMS, and the range of use has been increasing. They are also used as light source integrators for exposure apparatuses that use excimer lasers as light sources. Yes. Conventionally, as a method for manufacturing such a microlens, a method using optical lithography as disclosed in Japanese Patent Laid-Open No. 9-008266 (Patent Document 1) is known.

  In these methods, an ordinary photomask is used, a pattern corresponding to the microlens is formed on the mask, and the resist formed on the surface of the optical substrate is exposed and developed to produce a three-dimensional rectangular pattern of the resist. To do. Then, the three-dimensional rectangular pattern of this resist is deformed into a lens (curved surface) shape by heat flow to form a microlens. Further, if necessary, the lens-shaped resist is etched together with the optical base material to transfer the lens-shaped resist pattern to the optical base material, thereby forming a microlens made of the optical base material.

In recent years, a microlens manufacturing method based on a completely different principle has been developed and disclosed in Japanese Patent Laid-Open No. 2003-107209 (Patent Document 2). This is because the resist formed on the surface of the optical substrate is exposed to light using a gray scale mask (a mask having a change in light transmittance that can be regarded as analog), and the resist is developed. Form a three-dimensional resist pattern in the shape and use it as a microlens, or, as described above, etch the lens-shaped resist together with the optical substrate to form a lens-shaped resist pattern. It transfers to an optical base material and forms the micro lens which consists of an optical base material.

  An example is shown in FIG. A resist 2 is applied on a substrate 1 made of quartz (a). In this case, a positive type resist is used. Then, the resist 2 is irradiated with light through the gray scale mask 3 (b). In the figure, the hatched portion is a gray scale, and the light transmittance decreases toward the center of the hatched portion. The part which is not hatched is a transparent part.

  When the resist 2 exposed in this way is developed, the portion corresponding to the region where the transmittance of the mask is high increases the amount of exposure, so a lot of the resist 2 is removed, and the portion corresponding to the region where the transmittance of the mask is low Since the exposure amount is small, the removal amount of the resist 2 is reduced, and a pattern of a microlens array is formed on the resist 2 as shown in FIG.

  When the resist 2 and the substrate 1 are simultaneously dry-etched in such a state, the microlens pattern formed on the resist 2 is transferred to the substrate 1, and the microlens array is formed on the surface of the substrate 1 without the resist 2. Is formed. Depending on the etching rate difference between the resist 2 and the substrate 1, the microlens pattern formed on the resist 2 and the microlens pattern formed on the surface of the substrate 1 have different irregularities (SAG amount). The shape of the microlens pattern formed on the resist 2 may be determined in advance so that the microlens pattern having the above is formed on the surface of the substrate 1.

  The above examples relate to microlenses and microlens arrays, but similar techniques can be applied to the production of other optical elements such as diffraction gratings, Fresnel lenses, cylindrical lenses, cylindrical lens arrays, etc. It can be used when processing a fine pattern shape.

  Some optical elements have optical characteristics in the shape of a resist formed on a substrate. The method of manufacturing such a thing should just complete the process to (c) in the above processes, and let it be a finished product.

JP-A-9-008266 JP 2003-107209 A

  In the resist pattern forming method as described above, the relationship between the exposure amount, the development time, and the resist thickness removed by development is examined in advance, and when the desired resist pattern shape is determined, the shape is determined. Is determined such that the exposure amount and the development time can be obtained. Among these, since the development time is common to each part of the resist layer, the pattern corresponding to the shape of the resist pattern is mainly the exposure time until the development of the resist, which is the light transmission of the gray scale mask. This is achieved by changing the amount according to the target resist pattern.

  However, the resist thickness lost by development per unit time is not strictly the same for each portion of the resist layer, and varies depending on the shape of the resist pattern during development. Therefore, it is necessary to determine the development time in consideration of this.

  However, even if the exposure amount and the development time are determined so that a predetermined resist pattern shape can be obtained in this way, the sensitivity of the resist (the amount by which the resist thickness decreases with respect to the unit exposure amount and the unit development time) is Depending on the resist coating conditions, etc., it changes for each substrate. If the sensitivity of the resist is higher than expected, the development proceeds too much, deviating from the predetermined pattern shape, and adjustment is no longer possible and eventually discarded as a defective product. Become.

  In particular, in the case of a lens having a large amount of SAG, the resist coating thickness is increased (15 μm or more), and the development time is increased accordingly. Therefore, the instability of development is added, and the three-dimensional shape of the obtained resist is equal to the target shape. The gap increases.

  The present invention has been made in view of such circumstances, and a method for forming a resist pattern with good accuracy and yield, a method for manufacturing an optical element and a substrate using such a method for forming a resist pattern, and this method. It is an object of the present invention to provide a manufactured optical element and an exposure apparatus using the optical element.

  A first means for solving the problem is a method of forming a predetermined shape in the resist by exposing and transferring the pattern of the gray scale mask onto the resist, and then developing the resist. Based on the difference between the resist shape obtained as a result and the predetermined shape, the resist is developed by performing the first exposure in a time shorter than the exposure time required to form the shape of The resist is subjected to a second exposure for the determined time, and the resist is developed again (claim 1).

  As described above, when exposure and development are performed so that the resist shape is set to the target value from the beginning, if the resist sensitivity is higher than the assumed value, the thickness of the resist is excessively reduced as a result of development, and recovery is not possible. It becomes possible and becomes a defective product. In this means, when the exposure time and the development time necessary for forming the predetermined shape are determined, the first exposure is performed in a time shorter than the exposure time, and the resist is formed with the determined development time. And developing the resist again by performing the second exposure on the resist for a time determined based on the difference between the resulting resist shape and the predetermined shape. Yes. In principle, the necessary development time is used for both the first and second development times.

  Therefore, it is possible to avoid a situation in which the development proceeds too much in the first development. The second development is performed by determining the exposure amount based on the difference between the shape obtained as a result of the first exposure and development and the target shape, so that an accurate resist shape can be obtained. By making the second exposure amount less than the first exposure amount, even if the resist sensitivity in the second development and exposure is different from the expected one, the amount of development proceeds too much, and it is completed This increases the possibility that the resist shape can be within the tolerance. The first exposure and the second exposure may be divided into a plurality of times as long as the exposure amount until each development is a desired exposure amount.

  A second means for solving the above problem is a method of forming a predetermined shape in the resist by exposing and transferring the pattern of the gray scale mask onto the resist and then developing the resist. The first development is performed on the resist in a time shorter than the development time necessary for forming the pattern, and is determined based on the difference between the resist shape obtained as a result and the predetermined shape. And a step of performing the second development on the resist for a predetermined time (claim 2).

  Although this means has the same concept as the first means, the first means performs exposure in two steps, whereas this means divides development into two stages. Is going. That is, when the exposure time and development time necessary to form a predetermined shape are determined, the exposure time is determined using the determined exposure time, and the first development time is shorter than the determined exposure time. ing. Therefore, also in this means, an operational effect equivalent to that of the first means can be obtained. Also in this means, each exposure may be performed in a plurality of times as in the first means.

  A third means for solving the problem is a method of forming a predetermined shape in the resist by exposing and transferring the pattern of the gray scale mask onto the resist, and then developing the resist. Based on the difference between the resist shape obtained as a result and the predetermined shape, the resist is developed by performing the first exposure in a time shorter than the exposure time required to form the shape of The second development is performed on the resist for the time determined in the above (claim 3).

  In this means, when the exposure time and the development time necessary for forming the predetermined shape are determined, the exposure is performed in a time shorter than the exposure time, and the first development is performed with the determined development time. Is going. Then, the second development is performed on the resist for a time determined based on the difference between the resist shape obtained as a result and a predetermined shape. Therefore, also in this means, an operational effect equivalent to that of the first means can be obtained. The first exposure in this means may be performed in a plurality of times. At this time, it is sufficient that the sum of the plurality of exposure amounts is smaller than the exposure amount necessary to form a predetermined shape.

  A fourth means for solving the above problem is any one of the first to third means, wherein an organic developer is used as a resist developer. Item 4).

  As long as the experiment was conducted with the developer obtained by the inventor, the development of the resist multiple times using an inorganic developer would cause the resist surface to become rough and unsuitable for use as an optical element. End up. On the other hand, since this does not occur in the organic developer, it is preferable to use an organic developer as the developer when performing the first means and the second means.

  A fifth means for solving the above problem is a method of manufacturing an optical element having optical characteristics by forming a resist layer on a substrate and forming a pattern on the resist layer, The method further comprises a step of forming a pattern on the resist layer by the resist pattern forming method of any one of the first to fourth means.

  The basic configuration of this optical element manufacturing method is not different from that described in the background art section. In this means, the first means is used as a method for forming a resist pattern in this step. To 4th means. Therefore, an optical element with good shape accuracy can be manufactured.

  A fifth means for solving the problem is the first means, wherein a resist layer is formed on a substrate, a pattern is formed on the resist layer, and then the resist and the substrate are simultaneously etched. A method of manufacturing a substrate having a predetermined pattern on its surface by transferring the pattern of the resist layer to the substrate, wherein the resist pattern is formed by any one of the first to fourth means. It has the process of forming a pattern in a resist layer (Claim 6).

  The basic configuration of the substrate manufacturing method is not different from that described in the background art section. However, in this means, as a method for forming a resist pattern in this step, the first means is used. One of the fourth means is used. Therefore, a substrate with good shape accuracy can be manufactured.

  The seventh means for solving the above-mentioned problems is manufactured by the optical element manufacturing method as the fifth means or the substrate manufacturing method as the fifth means (claim). Item 7).

  Since the optical element in this means is manufactured by the optical element manufacturing method as the fifth means or the substrate manufacturing method as the sixth means, it becomes an optical element with good shape accuracy.

  An eighth means for solving the above problem is an exposure apparatus characterized in that the optical element of the seventh means is used as an optical element of an illumination optical system.

  In this means, since the optical element of the sixth means is used as the optical element of the illumination optical system, the accuracy of the illumination optical system can be improved. In particular, in an exposure apparatus using an excimer laser, fluorite is used as a transparent glass material, but an optical device using fluorite as a glass material is manufactured by the fifth method, thereby providing a highly accurate exposure apparatus. Can do.

  As described above, according to the present invention, a method for forming a resist pattern with good accuracy and yield, a method for manufacturing an optical element and a substrate using such a method for forming a resist pattern, and a method for manufacturing the resist pattern are manufactured by this method. An optical element and an exposure apparatus using the optical element can be provided.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a substrate manufacturing method according to the first embodiment of the present invention. A resist 2 is deposited on a quartz substrate 1 (a). In this case, a positive type resist is used. Then, the resist 2 is irradiated with light through the gray scale mask 3 (b). In the figure, the hatched portion is a gray scale, and the light transmittance decreases toward the center of the hatched portion. The part which is not hatched is a transparent part.

  When the resist 2 exposed in this way is developed, a lot of the portion that has been strongly irradiated with light is removed, and a portion that has been weakly irradiated with the light has a small amount of removal, as shown in FIG. A microlens array pattern is formed on the resist 2. In the step shown in FIG. 1B, exposure may be performed by dividing the number of exposures into a plurality of times.

  In the above process, an exposure amount and a development time for obtaining a target microlens shape are obtained, and the exposure amount is set smaller than an exposure amount for obtaining a target microlens shape. The development time is set so that the target microlens shape can be obtained. Therefore, in this state, the curvature of the resist pattern that is generally obtained is smaller than the curvature of the target resist pattern. In this state, the shape of the resist pattern is measured using a stylus type shape meter or the like, and the difference from the target shape of the resist pattern is obtained.

  Next, using the gray scale mask 3 again, re-exposure is performed for an exposure time determined in accordance with the difference between the actual value of the resist pattern and the target value (d). When the resist is developed again, a resist shape very close to the target pattern shape is obtained (e). The development time at this time may be the same as the first development time, and may be determined together with the exposure time when determining the second exposure time. In the second exposure, the number of exposures may be divided into a plurality of exposures.

  When the resist 2 and the substrate 1 are simultaneously dry-etched in such a state, the microlens pattern formed on the resist 2 is transferred to the substrate 1, and the microlens array is formed on the surface of the substrate 1 without the resist 2. Is formed. The microlens pattern formed on the resist 2 and the microlens pattern formed on the surface of the substrate 1 are different in degree of unevenness due to the difference in etching rate between the resist 2 and the substrate 1. The shape of the microlens pattern formed on the resist 2 may be determined in advance so that the above pattern is formed on the surface of the substrate 1.

  In the case where the resist pattern shape itself is used as an optical element, the manufacturing process is completed at the step (e) in FIG. 1, and a product as shown in (e) is obtained.

  FIG. 2 is a schematic view showing a substrate manufacturing method according to the second embodiment of the present invention. In this embodiment, unlike the embodiment shown in FIG. 1, exposure after development is not performed, and only development is performed in two steps. A resist 2 is applied on a substrate 1 made of quartz (a). In this case, a positive type resist is used. Then, the resist 2 is irradiated with light through the gray scale mask 3 (b). In the figure, the hatched portion is a gray scale, and the light transmittance decreases toward the center of the hatched portion. The part which is not hatched is a transparent part. Actually, the exposure to be performed is not limited to one time, but may be performed in a plurality of times until development is performed.

  When the resist 2 exposed in this way is developed, a lot of the portion that has been strongly irradiated with light is removed, and a portion that has been weakly irradiated with the light has a small amount of removal, as shown in FIG. A microlens array pattern is formed on the resist 2.

  In the above steps, an exposure amount and a development time are obtained so as to obtain a target microlens shape, and the development time is set shorter than a development time such that a target microlens shape is obtained. The exposure time is set so that the target microlens shape can be obtained. Therefore, in this state, the curvature of the resist pattern that is generally obtained is smaller than the curvature of the target resist pattern. In this state, the shape of the resist pattern is measured using a stylus type shape meter or the like, and the difference from the target shape of the resist pattern is obtained.

  Next, when re-development is performed for a development time determined corresponding to the difference between the actual value of the resist pattern and the target value, a resist shape very close to the target pattern shape is obtained (d).

  When the resist 2 and the substrate 1 are simultaneously dry-etched in such a state, the microlens pattern formed on the resist 2 is transferred to the substrate 1, and the microlens array is formed on the surface of the substrate 1 without the resist 2. Is formed. The microlens pattern formed on the resist 2 and the microlens pattern formed on the surface of the substrate 1 are different in degree of unevenness due to the difference in etching rate between the resist 2 and the substrate 1. The shape of the microlens pattern formed on the resist 2 may be determined in advance so that the above pattern is formed on the surface of the substrate 1.

  In the case where the resist pattern shape itself is used as an optical element, the manufacturing process is completed at the step (d) in FIG. 2, and a product as shown in (d) is a finished product.

  The substrate manufacturing method according to the third embodiment of the present invention is the same as that shown in FIG. 2, but in the third embodiment, exposure is performed so as to obtain a target microlens shape. The amount and the development time are obtained, and the exposure time is set to be shorter than the exposure time determined by the relationship between the exposure time and the development time so as to obtain the target microlens shape. Then, although the development is performed in two steps, the first development time is set to an exposure time for obtaining the target microlens shape. Then, since the exposure time is insufficient, a pattern as shown in FIG. 2C is obtained. After that, as in the second embodiment, the shape of the resist pattern is measured using a stylus shape meter or the like, and the difference from the target shape of the resist pattern is obtained.

  Next, when redevelopment is performed for a development time determined in accordance with the difference between the actual value of the resist pattern and the target value, a resist shape very close to the target pattern shape is obtained (d). Subsequent processes and the like are the same as those in the second embodiment.

  FIG. 3 shows an outline of the optical system of the exposure apparatus according to the embodiment of the present invention. In FIG. 3, the Z axis along the normal direction of the wafer W coated with the resist, the Y axis in the direction parallel to the plane of FIG. 3 in the wafer plane, and the plane perpendicular to the plane of FIG. 3 in the wafer plane. The X axis is set for each direction. In FIG. 3, the illumination optical device is set to perform annular illumination.

  The exposure apparatus shown in FIG. 3 includes, as a light source 11 for supplying exposure light (illumination light), for example, a KrF excimer laser light source that supplies light with a wavelength of 248 nm or an ArF excimer laser light source that supplies light with a wavelength of 193 nm. ing. A substantially parallel light beam emitted from the light source 11 along the Z direction has a rectangular cross section elongated along the X direction, and enters a beam expander 12 including a pair of lenses 12a and 12b. The light beam is shaped into a light beam having a rectangular cross section.

  The substantially parallel light beam that has passed through the beam expander 12 as a shaping optical system is deflected in the Y direction by the bending mirror 13 and then enters the afocal zoom lens 15 through the diffractive optical element 14. In general, a diffractive optical element is formed by forming a step having a pitch of about the wavelength of exposure light (illumination light) on a glass substrate, and has a function of diffracting an incident beam to a desired angle. Specifically, the diffractive optical element 14 has a function of forming a circular light intensity distribution in the far field (or Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section is incident. Therefore, the light beam passing through the diffractive optical element 14 forms a circular light intensity distribution, that is, a light beam having a circular cross section at the pupil position of the afocal zoom lens 15.

  The afocal zoom lens 15 is configured so that the magnification can be continuously changed within a predetermined range while maintaining an afocal system (non-focus optical system). The light beam that has passed through the afocal zoom lens 15 enters the diffractive optical element 16 for annular illumination. The afocal zoom lens 15 optically substantially conjugates the divergence origin of the diffractive optical element 14 and the diffractive surface of the diffractive optical element 16. The numerical aperture of the light beam condensed on one point of the diffractive surface of the diffractive optical element 16 or a surface in the vicinity thereof changes depending on the magnification of the afocal zoom lens 15.

  The diffractive optical element 16 for annular illumination has a function of forming a ring-shaped light intensity distribution in the far field when a parallel light beam is incident.

  The light beam that has passed through the diffractive optical element 16 enters the zoom lens 17. In the vicinity of the rear focal plane of the zoom lens 17, the incident surface (that is, the first eye) of the micro fly-eye lens (or fly-eye lens) 18 including the first fly-eye member 18 a and the second fly-eye member 18 b in order from the light source side. The incident surface of the first fly-eye member 18a) is positioned. The micro fly's eye lens 18 functions as an optical integrator that forms a large number of light sources based on incident light beams.

  As described above, the luminous flux from the circular light intensity distribution formed at the pupil position of the afocal zoom lens 15 via the diffractive optical element 14 is emitted from the afocal zoom lens 15 and then has various angular components. Is incident on the diffractive optical element 16. That is, the diffractive optical element 16 constitutes an optical integrator having an angle beam forming function. On the other hand, the diffractive optical element 16 has a function of forming a ring-shaped light intensity distribution in the far field when a parallel light beam is incident. Therefore, the light beam that has passed through the diffractive optical element 16 forms an annular illumination field centered on the optical axis AX, for example, on the rear focal plane of the zoom lens 17 (and hence on the incident surface of the micro fly's eye lens 18). .

  The outer diameter of the annular illumination field formed on the incident surface of the micro fly's eye lens 18 changes depending on the focal length of the zoom lens 17. Thus, the zoom lens 17 substantially connects the diffractive optical element 16 and the incident surface of the micro fly's eye lens 18 in a Fourier transform relationship. The light beam incident on the micro fly's eye lens 18 is two-dimensionally divided, and a large number of ring-shaped members having the same annular area as the illumination field formed by the light beam incident on the micro fly's eye lens 18 on the rear focal plane of the micro fly eye lens 18. A light source (hereinafter referred to as “secondary light source”) is formed.

  The light beam from the annular secondary light source formed on the rear focal plane of the micro fly's eye lens 18 is subjected to the light collecting action of the condenser optical system 19 and then superimposed on the mask M on which a predetermined pattern is formed. To illuminate. The light beam that has passed through the pattern of the mask M forms an image of the mask pattern on the wafer W coated with the resist via the projection optical system PL. Thus, by performing batch exposure or scan exposure while driving and controlling the wafer W two-dimensionally in a plane (XY plane) orthogonal to the optical axis AX of the projection optical system PL, each exposure region of the wafer W is masked. M patterns are sequentially exposed.

  Thus, in the exposure apparatus according to the present embodiment, the diffraction gratings 14 and 16 are used as means for forming a ring-shaped light intensity distribution in the far field. As this diffraction grating, a fluorite surface processed with a grating pattern is used, and this diffraction grating is manufactured by the optical element manufacturing method according to the present invention as described above. Therefore, even when a material such as fluorite is used, the grating pattern can be formed accurately and quickly, and a desired illumination pattern can be obtained.

  Further, since the diffraction gratings 14 and 16 are close to the light source, it is preferable that the diffraction gratings 14 and 16 are not easily deteriorated even when a large amount of high energy light such as ArF laser light or KrF laser light is irradiated. Therefore, by using the fluorite as a material and manufacturing the diffraction gratings 14 and 16 by the method of the present invention and using them in the illumination optical system of such an exposure apparatus, a long length that has not been obtained so far. Expect to have a lifetime.

  Furthermore, since a light source image is formed on the exit surface of the micro fly's eye lens 18 and energy is concentrated here, the micro fly's eye lens 18 is also preferably manufactured by using the method of the present invention using fluorite. .

(Example 1)
A resist microlens having a lens diameter of 500 μm and a target curvature R = 680 μm was manufactured. First, a resist having a thickness of 55 μm (PLL series manufactured by Clarity Japan) was applied on an optical substrate (quartz substrate). This thick film resist was exposed by a g-line stepper using a gray scale mask whose transmittance was modulated by the opening. The preset exposure time was 8000 msec and the development time was 20 minutes. However, in actuality, the first exposure was performed at an exposure time of 8000 msec, and development was performed for 17 minutes using an organic developer (NMD3 manufactured by Tokyo Ohka Kogyo Co., Ltd.).

  As a result of measuring the shape of the microlens after the first development, the curvature R was 710 μm, and the shape error of each part with respect to the curvature R = 710 μm was as shown by the thin line in FIG. Since the exposure time is shorter than the set exposure time, the shape of the resist after development is different from the target shape (curvature R = 680 ± 7 μm), but each part for the obtained curvature R = 710 μm The shape error is as small as 0.2 μm or less at maximum.

  When the re-development time corresponding to the difference between the target curvature of 680 μm and the actual curvature of 710 μm was determined to be 3 minutes, the second development was performed for 3 minutes. The resulting shape had a curvature R = 684 μm and entered a target curvature R = 680 μm ± 7 μm (± 1%). Further, the shape error with respect to the curvature R = 684 μm was as shown by the thick line in FIG. As can be seen from FIG. 4, by performing additional development for 3 minutes, only the curvature could be changed without changing the shape error.

(Example 2)
A resist microlens having a lens diameter of 500 μm and a target curvature R = 680 μm was manufactured. First, a resist having a thickness of 55 μm (PLL series manufactured by Clarity Japan) was applied on an optical substrate (quartz substrate). This thick film resist was exposed by a g-line stepper using a gray scale mask whose transmittance was modulated by the opening. The preset exposure time was 8000 msec and the development time was 20 minutes. However, actually, the first exposure was performed at an exposure time of 7200 msec, and development was performed for 20 minutes using an organic developer (NMD3 manufactured by Tokyo Ohka Kogyo Co., Ltd.).

  As a result of measuring the shape of the microlens after the first development, the curvature R was 714 μm, and the shape error of each part with respect to the curvature R = 714 μm was as shown by the thin line in FIG. Since the exposure time is shorter than the set exposure time, the shape of the resist after development differs from the target shape (curvature R = 680 ± 7 μm), but each part for the obtained curvature R = 714 μm The maximum shape error is as small as 0.3 μm or less.

  When the re-development time corresponding to the difference between the target curvature of 680 μm and the actual curvature of 710 μm was determined to be 3 minutes, the second development was performed for 3 minutes. The resulting shape had a curvature R = 684 μm and entered a target curvature R = 680 μm ± 7 μm (± 1%). Further, the shape error with respect to the curvature R = 686 μm was as shown by the thick line in FIG. As can be seen from FIG. 5, by performing the additional development for 3 minutes, only the curvature could be changed without changing the shape error.

It is a schematic diagram which shows the manufacturing method of the board | substrate which is the 1st Embodiment of this invention. It is a schematic diagram which shows the manufacturing method of the board | substrate which is the 2nd Embodiment of this invention. It is a figure which shows the outline | summary of the optical system of the exposure apparatus which is embodiment of this invention. It is a figure which shows the shape error of the microlens in the Example of this invention. It is a figure which shows the shape error of the microlens in the Example of this invention. It is a schematic diagram which shows the method of manufacturing the conventional microlens.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Resist, 3 ... Gray scale mask, 11 ... Light source, 12 ... Beam expander, 12a, 12b ... Lens, 13 ... Bending mirror, 14 ... Diffractive optical element, 15 ... Afocal zoom lens, 16 ... Diffraction Optical element, 17 ... zoom lens, 18 ... micro fly's eye lens, 18a ... first fly eye member, 18b ... second fly eye member, 19 ... condenser optical system, M ... mask, PL ... projection optical system, W ... wafer

Claims (8)

A method of forming a predetermined shape on the resist by exposing and transferring the pattern of the gray scale mask to the resist and then developing the resist, and having a time longer than an exposure time required to form the predetermined shape The first exposure is performed in a short time to develop the resist, and the second exposure is performed for a time determined based on the difference between the resist shape obtained as a result and the predetermined shape. A method of forming a resist pattern, comprising: performing the resist again and developing the resist again. A method of forming a predetermined shape on the resist by exposing and transferring the pattern of the gray scale mask to the resist and then developing the resist, and the development time required to form the predetermined pattern is longer The first development is performed on the resist in a short time, and the second development is performed on the resist for a time determined based on the difference between the resist shape obtained as a result and the predetermined shape. A method for forming a resist pattern, comprising a step of performing the process. A method of forming a predetermined shape on the resist by exposing and transferring the pattern of the gray scale mask to the resist and then developing the resist, and having a time longer than an exposure time required to form the predetermined shape The first exposure is performed in a short time to develop the resist, and the second development is performed for a time determined based on the difference between the resist shape obtained as a result and the predetermined shape. A method for forming a resist pattern, comprising a step of performing the process on the resist. The method for forming a resist pattern according to claim 1, wherein an organic developer is used as the resist developer. A method for manufacturing an optical element having optical characteristics by forming a resist layer on a substrate and forming a pattern on the resist layer, wherein: A method for producing an optical element, comprising a step of forming a pattern on a resist layer by the method for forming a resist pattern described above. After forming a resist layer on the substrate and forming a pattern on the resist layer, the resist and the substrate are simultaneously etched to transfer the pattern of the resist layer to the substrate and have a predetermined pattern on the surface A method for manufacturing a substrate, comprising the step of forming a pattern on a resist layer by the method for forming a resist pattern according to any one of claims 1 to 4. . An optical element manufactured by the method for manufacturing an optical element according to claim 5 or the method for manufacturing a substrate according to claim 6. An exposure apparatus using the optical element according to claim 7 as an optical element of an illumination optical system.

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