JP2006258834A - Manufacturing method of microlens and manufacturing method of mold for microlens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a microlens having a small manufacturing error. <P>SOLUTION: Parts of masks 5a to 5g smeared away black are light shielding sections and annular parts with hatching transmit light. A resist 4 is exposed by using the masks 5a to 5f among these six sheets of masks. When exposing by using respective masks, exposure is performed with exposure quantity corresponding to SAG amount (amount of sensitization) of respective irradiation regions. Consequently exposure amounts at respective parts A, B, C, D, E and F are different and owing to the difference, a photoresist microlens having a resist surface of a step shape shown by 3 in Fig.(b) can be formed when the resist 4 is developed. After exposing the resist 4 by using the masks 5a to 5f, exposure is performed by using the mask 5g for complete exposure having all transparent exposure regions A to F. Thereby when developed, parts of a step shape shown in Fig.(b) become a blunt shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a microlens using photolithography (the microlens referred to in the present specification and claims includes a microlens array. As the microlens, an aspherical lens, a cylindrical lens, etc. Of course, not only those that are recognized as lenses, but also those that have optical power due to relief patterns, such as Fresnel lenses and diffraction gratings, and anything that has optical power when transmitting light due to the shape of the surface. And the manufacturing method of the microlens mold.

  Microlenses have been put into practical use mainly in the fields of digital cameras, optical communication, and MEMS, and the range of use has been increasing.

  As a method for manufacturing such a microlens, methods described in, for example, Japanese Patent Application Laid-Open No. 7-191209 (Patent Document 1) and Japanese Patent Application Laid-Open No. 8-187778 (Patent Document 2) are known.

  These methods approximate the shape of a curved lens to the shape of a stepped surface, apply a resist on the substrate, and use multiple masks to expose the exposure corresponding to each stepped surface. A method of manufacturing a photoresist microlens having a stepped surface by exposing a resist and developing the resist, and etching the resist and the substrate at the same time to form the shape of the resist thus formed This is a method for producing a microlens made of a substrate by transferring it to the substrate.

  An example of such a microlens manufacturing method is shown in FIG. FIG. 9 is a view showing a cross section of a rotationally symmetric spherical shape centered on a one-dot chain line. In (b), 21 is a substrate such as glass, and 22 is a curved surface of a photoresist microlens to be formed on the substrate 21. The curved surface 22 is approximated by a stepped surface shape such as 23. In this case, the curved surface 22 is a spherical surface, and the surface shape 23 is a surface shape when disks having different radii are stacked.

  That is, instead of forming a photoresist microlens whose surface has a shape like a curved surface 22, a photoresist microlens whose surface has a step shape such as a surface shape 23 is formed. For this purpose, first, a resist is applied on the substrate 21 to a height indicated by a two-dot chain line 24.

  On the other hand, masks as shown in 25a to 25f of (a) are prepared correspondingly. These masks 25a to 25f are made of glass or the like, and the portions painted black are plated with chrome or the like so as to block light rays. The annular portion with oblique hatching is transparent and allows light to pass through.

  The resist 24 is exposed using these five masks 25a to 25f. Then, no exposure is performed in the portion A, only exposure using the mask 25a is performed in the portion B, exposure is performed using the masks 25a and 25b in the portion C, and masks 25a, 25b, and 25c are performed in the portion D. The portion E is exposed by the masks 25a, 25b, 25c, and 25d, and the portion F is exposed by the entire mask.

  As a result, the exposure amounts of the respective portions A, B, C, D, E, and F are different. Due to this difference, when the resist 24 is developed, the surface shape of the resist as indicated by 23 is shown. Thus, a photoresist microlens having a stepped shape can be formed.

  Also, from this state, when the resist and the substrate 21 are dry-etched to remove the resist, the surface shape as indicated by 23 is transferred to the substrate 21, and a microlens having a stepped shape made of the substrate 21 is formed. The

  A method of manufacturing a microlens using a gray scale mask that is completely different from such a microlens is disclosed in JP-T-8-504515 (Patent Document 3). This is because the resist formed on the surface of the substrate is exposed using a gray scale mask (a mask having a change in light transmittance that can be regarded as analog), and the resist is developed to develop a shape corresponding to the gray scale. Form a three-dimensional resist pattern and use it as a microlens, or transfer the lens-shaped resist pattern to the substrate by etching the resist in the shape of a lens with the substrate as described above. A microlens made of a substrate is formed.

JP 7-191209 A JP-A-8-187781 JP-T 8-504515 JP 2004-198735 A Japanese Patent Laid-Open No. 9-8266

  However, the microlens manufacturing methods described in Patent Document 1 and Patent Document 2 have the following problems. In FIG. 9, for simplicity, exposure is performed using five masks. However, if the shape is to be approximated precisely, the number of masks increases, and usually ten or more masks are required. Become.

  On the other hand, accurate additivity does not hold between the amount lost when the resist is developed (referred to as “photosensitive amount”) and the exposure amount. That is, when the exposure amount of (a + b) is given at once and when the exposure amount of a and the exposure amount of b are given separately, the exposure amount is not the same.

  Further, when the exposure amount of a and the exposure amount of b are separately given, the extent of the exposure amount depends on the resist pre-baking conditions, the time from pre-baking to exposure, and development after exposure. It depends on the time until. In addition, when the exposure amount when a certain mask is used to adjust the exposure amount of a predetermined stepped portion, the change in the exposure amount affects the exposure amount of another stepped portion. Become. Therefore, it is actually difficult to form a precise step-like resist shape by the microlens manufacturing method as described in Patent Document 1 and Patent Document 2.

  In addition, heat flow treatment is performed in order to obtain a stepped shape as a curved surface. In the heat flow treatment, the resist is heated to deform and smooth the surface. However, in this method, since the resist is heated to the inside, the deformation of the resist becomes large, the surface of the stepped shape is not only smoothed, but the shape (for example, the curvature) itself may change. There is also a problem that there is.

  On the other hand, in the method using a gray scale mask, it is necessary to manufacture the mask by accurately controlling the opening area and the light shielding area, and there is a problem in that special equipment and technology are required to manufacture the mask. . Furthermore, when the relationship between the exposure amount of the resist and the exposure amount changes, it is inevitable that the shape of the formed microlens changes, but there is a problem that it is difficult to adjust this change. .

  As a method for solving such a problem, the present inventors applied a resist on a substrate, and exposed each region having the same height in the stepped portion using a single mask, Subsequently, a method for producing a microlens characterized by having a step of developing a resist has been invented, and a patent application has been filed as Japanese Patent Application No. 2004-285666 (referred to as a prior invention).

  According to the invention of the prior application, when forming a microlens having a resist shape whose curved surface is approximated by a stepped pattern, the regions having the same height in the stepped portion are exposed using one mask each. Then, since there is a step of developing the resist, even when the relationship between the exposure amount of the resist and the exposure amount changes, the exposure amount when performing exposure using each mask is adjusted (for example, the exposure time is adjusted). Or adjusting the intensity of the light source), the desired resist exposure can be easily obtained, and the adjustment result in one stepped portion may affect the other stepped portion. Absent. Therefore, the microlens can be manufactured by a simple method, and can be easily adjusted even when the resist conditions change.

  However, even in the prior invention, it is inevitable that the boundary of the region exposed by each mask has a certain level of step shape, and as a result, the shape error of the completed microlens may increase.

  The present invention has been made in view of such circumstances, and provides a method for manufacturing a microlens and a method for manufacturing a microlens mold with a smaller manufacturing error by improving the problems of the invention of the prior application. Let it be an issue.

  The first means for solving the above problem is a method of manufacturing a microlens formed from a stepped pattern approximating a concave shape, a convex shape, or a concave and convex shape, and applying a resist on a substrate, Areas having the same height in the stepped pattern are exposed using one mask each, and after the exposure using these masks is completed, all the exposure areas are collectively exposed with an equal exposure amount. A method of manufacturing a microlens, which includes a step of performing exposure and then developing a resist.

  In this means, when forming a microlens having a resist shape whose curved surface is approximated by a staircase pattern, each region having the same height in the staircase pattern is exposed using one mask, Thereafter, there is a step of developing the resist. Therefore, even when the relationship between the exposure amount of the resist and the exposure amount changes, the exposure amount when performing exposure using each mask is adjusted (for example, the exposure time is adjusted or the intensity of the light source is adjusted). Therefore, the exposure amount of the target resist can be easily obtained, and the adjustment result in one stepped portion does not affect the other stepped portion. And can be easily adjusted even when the resist conditions change.

  In this means, there is a problem that the alignment of the area to be exposed must be performed accurately using each mask, but this can be sufficiently dealt with by using the current stepper.

  Further, in the present means, after exposing the regions having the same height in the stepped portion by using one mask each, the entire exposure region is collectively exposed with the same exposure amount. Then, the resist is developed. As will be shown later in the examples, this batch exposure reduces the fine irregularities of the resist surface shape compared to the case where batch exposure is not performed, and provides a resist microlens with a smooth surface and good shape accuracy. .

  The second means for solving the problem is the first means, after developing the resist, removing the resist by simultaneously etching the resist and the substrate, and forming the resist on the resist It has the process of transferring the shape formed to the said board | substrate.

  In this means, the step of removing the resist by etching the resist and the substrate at the same time and transferring the shape formed in the resist to the substrate consists of the substrate alone by combining with the first means. A highly accurate microlens can be manufactured.

  According to a third means for solving the above problem, the lens shape is approximated to a stepped pattern that approximates a concave shape, a convex shape, or a concavo-convex shape, and the stepped shape resist is obtained by the first means. A microlens having a step of smoothing the stepped portion by exposure to an atmosphere of a solvent vapor that dissolves the resist. is there.

  In this means, after manufacturing a microlens having a step-shaped resist by the first means, the microlens is exposed to an atmosphere of a solvent vapor that dissolves the resist (referred to as a solvent vapor method). A step of smoothing the shaped portion.

  The solvent vapor method is a technique described in Japanese Patent Application Laid-Open No. 2004-198735 (Patent Document 4). By exposing the resist layer to a vapor of a solvent that dissolves the resist, only the surface of the resist is dissolved. This is a technique for smoothening the resist surface.

  According to this means, the stepped surface can be smoothed and brought close to the target surface shape. Furthermore, unlike the case of using heat flow, the resist remains dissolved only in the vicinity of the surface, so that the resist is not greatly deformed, for example, causing a change in curvature.

  A fourth means for solving the above problem is the third means, wherein the resist is removed by simultaneously etching the resist and the substrate after smoothing the stepped portion of the resist. And a method of manufacturing a microlens, comprising a step of transferring the shape formed in the resist to the substrate.

  In this means, a microlens composed only of a substrate can be manufactured by using a process of removing the resist by simultaneously etching the resist and the substrate and transferring the shape formed in the resist to the substrate. it can.

  A fifth means for solving the above problem is a method for manufacturing a microlens mold in which the microlenses of the first to fourth means are replaced with a microlens manufacturing mold.

  In the first to fifth means, a microlens is manufactured. However, the manufactured microlens can be used not as a microlens but as a mold for manufacturing a microlens. In this case, the resist is not necessarily transparent. Furthermore, nickel plating or the like may be applied to the surface of the resist or the substrate to improve the durability as a mold.

  ADVANTAGE OF THE INVENTION According to this invention, the problem which prior invention invention has can be improved, and the manufacturing method of a microlens with a smaller manufacturing error and the manufacturing method of a microlens type | mold can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of an embodiment in the case of manufacturing a photoresist spherical microlens. FIG. 1 is a view showing a cross section of a rotationally symmetric circle centered on a one-dot chain line. In (b), 1 is a substrate such as glass, and 2 is a curved surface of a photoresist microlens to be formed on the substrate 1. The curved surface 2 is approximated by a stepped surface shape such as 3. In this case, the curved surface 2 is a spherical surface, and the surface shape 3 is a stepped surface shape when disks having different radii are stacked.

  That is, instead of forming a photoresist microlens whose surface has a shape like a curved surface 2, a photoresist microlens whose surface has a step shape such as a surface shape 3 is formed. For this purpose, first, a resist is applied on the substrate 1 to a height indicated by a two-dot chain line 4.

  On the other hand, corresponding to this, a mask as shown in 5a to 5g of (a) is prepared. These masks 5a to 5g are made of glass or the like, and chrome or the like is applied to the blacked portions so as to block the light rays. The annular portion with oblique hatching is transparent and allows light to pass through.

  Of these six masks, the resist 4 is exposed using the masks 5a to 5f. Then, in the portion A, no exposure is performed at all, in the portion B, only the exposure with the mask 5a is performed, in the portion C, the exposure with only the mask 5b is performed, and in the portion D, the exposure with only the mask 5c is performed. In the portion E, exposure using only the mask 5d is performed, and in the portion F, exposure using only the mask 5f is performed. In exposure using each mask, exposure is performed with an exposure amount corresponding to the SAG amount (photosensitivity amount) of each irradiation region.

  As a result, the exposure amounts of the respective portions A, B, C, D, E, and F are different. Due to this difference, when the resist 4 is developed, the surface surface of the resist is indicated by 3. Thus, a photoresist microlens having a stepped shape can be formed.

  In the present embodiment, after the resist 4 is exposed using the masks 5a to 5f, the exposure is performed using the entire surface exposure mask 5g in which the entire exposure areas A to F are transparent. The exposure time at this time is short. Thereby, when the stepped portion in FIG. 1B is developed, it becomes a rounded shape.

  Also, from this state, when the resist and the substrate 1 are dry-etched to remove the resist, the surface shape as indicated by 3 is transferred to the substrate 1, and a microlens having a stepped shape made of the substrate 1 is formed. The

  In this embodiment, each of the portions A, B, C, D, E, and F is exposed by a single mask and a full exposure mask 5g that exposes the entire exposure region. The exposure amount in each part is determined according to the target exposure amount (corresponding to the SAG amount) when the masks 5a to 5f are used. In this embodiment, the exposure time is set as follows. It can be easily adjusted by changing. You may adjust by changing the intensity of a light source.

  And even if it changes the exposure amount when using each mask 5a-5f, only the area | region exposed with the mask is influenced, and another area | region is not influenced. Therefore, even if the relationship between the exposure dose and the exposure dose varies depending on the resist pre-baking conditions and the time from pre-baking to exposure, etc., it is possible to grasp the changed relationship and perform exposure using each mask. Since it is sufficient to determine a new exposure amount for each mask in accordance with the amount of light required for the adjustment, the adjustment is remarkably simplified as compared with the case of using a multiple mask.

  FIG. 1 illustrates the case of a spherical lens. However, an aspherical lens, a cylindrical lens, a Fresnel lens, a diffraction grating or the like having an optical power such as a diffraction pattern, and the like, and other light is transmitted due to the shape of the surface. When manufacturing what has optical power, it can manufacture by the same method.

  That is, a plurality of virtual surfaces (not necessarily equally spaced in the height direction) that cut such a predetermined number of optical elements in the height direction are considered, and virtually When the cutting is performed, a figure cut by the contour lines as seen in the plan view is drawn. A mask in which a portion between the contour lines and adjacent contour lines is a light transmitting portion is manufactured, and the resist is exposed using each mask. At that time, it goes without saying that the exposure amount when each mask is used is determined in accordance with the required exposure amount.

  In any case, in the lens manufactured by the manufacturing process as described above, the resist serves as an optical base material to generate optical power. Since the step structure of the resist is formed more gently than in the prior invention, it can be used as a lens normally. However, strictly speaking, the target surface shape may not be achieved. An example of a method for bringing such a lens closer to the target shape will be described with reference to FIG. This is a method of smoothing the surface of the resist by a so-called solvent vapor method.

  A solvent 9 for dissolving a resist 7 having a lens shape (a microlens array is shown in the figure) formed on the substrate 6 is put in the petri dish 8 and a lid (not shown) is used.

  For example, when a novolac resin-based positive photoresist is used as the photoresist, PGMEA (propylene glycol monomethyl ether acetate) is used as the solvent. And the pressure of the solvent vapor | steam 10 in the petri dish 8 reaches a saturated vapor pressure by maintaining a fixed temperature (for example, 23 degreeC). The solvent vapor 10 is PGMEA vapor.

  In order not to disturb this state, the lid is quickly replaced with the substrate 6 having the resist 7 on which the microlens array shape is formed, and the resist 7 is sealed with the surface facing downward. At this time, the substrate 6 serves as a lid for the petri dish 8, and the saturated vapor pressure of the solvent vapor 10 is maintained.

  In this way, the surface of the resist 7 is exposed to the solvent vapor 10. Then, the surface of the resist that forms the microlenses is dissolved, so that the level difference formed on each microlens is eliminated, and the surface becomes smooth.

  In the solvent vapor method, the photoresist used for the photoresist layer is preferably a novolac resin. As a solvent for dissolving the photoresist used in the solvent vapor method (hereinafter simply referred to as a solvent), as long as it dissolves the photoresist layer on which the optical surface to be processed is formed, in particular, dilution of the photoresist, It is not limited to those generally used for washing and the like, and in addition to ketones and alcohols, ethers such as dioxane and ethylene glycol monomethyl ether are preferable, and PGMEA (propylene glycol methyl ether) is more preferable. Also, a certain type of thinner (for example, PM thinner manufactured by Tokyo Ohka Co., Ltd.) can be preferably used.

  The solvent vapor used in the solvent vapor method is obtained, for example, by evaporating the solvent vapor from the liquid surface of the solvent by keeping the solvent for dissolving the photoresist at an appropriate temperature.

  In order to stably perform the solvent vapor process, it is preferable that the vapor pressure of the solvent during the solvent vapor process be spatially uniform and constant in time. Therefore, the vapor pressure of this solvent is a saturated vapor pressure at which the amount of vapor evaporated (vaporized) from the solvent and the amount of vapor returning to the liquid level of the solvent (liquefied) at a constant temperature is balanced, It is preferable to perform a process of exposing the optical element to be processed to this saturated vapor. One method is to keep the solvent at a predetermined temperature T in the sealed container, evaporate the solvent, and at the same time keep the inner surface of the sealed container at the temperature T.

  In order to perform the process of the solvent vapor method, it is preferable that the optical element to be processed is also kept at the temperature T in advance when the optical element to be processed is set in the sealed container.

  In the solvent vapor method, the solvent vapor chemically acts on the step of the optical surface of the photoresist layer to be processed, and the processing proceeds by dissolving only the surface of the step. The processing conditions are optimized by adjusting the type of solvent, the processing temperature, and the processing time. By performing processing under this optimized condition, the level difference of the optical surface of the optical element to be processed becomes smooth, and the shape accuracy of the optical surface does not change.

  When the treatment temperature T rises during the treatment by the solvent vapor method, the vapor pressure of the solvent rises, so that the amount of the solvent vapor reaching the uneven portion to be treated increases and the treatment speed increases. The degree to which the unevenness is processed, that is, the processing amount increases in proportion to the product of the processing speed and the processing time. If the processing amount is too small, the effect of improving the degree of unevenness is insufficient, and if it is too large, the shape accuracy of the optical surface is changed, so there is an optimum processing amount. If the processing temperature is too high, the processing time may be short, but the processing quality is not stable, and if it is too low, the processing takes too much time, which is not preferable, and an optimum processing temperature exists. The optimum processing temperature depends on the shape of the optical surface to be processed, the type of photoresist, and the type of solvent, and is determined by repeated testing.

  The difference between the maximum height and the minimum height of the lens surface of the lens thus manufactured is preferably 5 μm or less. In other words, if this difference increases, the step must be increased or the number of masks to be used must be increased. However, increasing the step causes the optical characteristics of the lens to deteriorate, and increasing the number of masks increases the number of exposures. Will increase. When the difference between the maximum height and the minimum height of the lens surface is 5 μm or less, a microlens having practically sufficient accuracy can be obtained without complicating the process so much.

  Using the resist having a lens shape manufactured as described above as an intermediate material, the resist and the substrate are dry etched to remove the resist, thereby transferring the resist shape to the substrate (the resist and the substrate). In consideration of the etching rate, it is needless to say that the shape of the resist is adjusted in advance so that the desired shape can be obtained on the substrate), and a microlens composed only of the substrate can also be formed. This method is described in, for example, Japanese Patent Laid-Open No. 9-8266 (Patent Document 5), and is well known, and thus the description thereof is omitted. In this case, it is not necessary to use a translucent resist.

  The method described above is a method of directly manufacturing a microlens by a photolithography process. However, these may be used as a mold, and a resin microlens array may be manufactured using this mold.

  Such a method is illustrated in FIG. In FIG. 3, a substrate having a resist 12 in which the shape of a microlens array is formed on a substrate 11 is used as a mold (a).

  An ultraviolet curable resin is injected between the mold and a surface plate 13 transparent to ultraviolet rays by using a dispenser or the like to inject and press the ultraviolet curable resin 14 and then irradiating ultraviolet rays through the surface plate 13. 14 is cured (b). Then, after that, the ultraviolet curable resin 14 is peeled off from the mold and the surface plate 13, whereby a resin microlens array can be manufactured (c). In this case, it goes without saying that the substrate 11 and the resist 12 do not have to be transparent.

  Further, the resin-made microlens array thus formed is not used as a microlens array but is used as a mold, and a dispenser or the like is provided between the mold and a surface plate 13 'transparent to ultraviolet rays. After injecting and pressing the ultraviolet curable resin 14 'using UV, the ultraviolet curable resin 14' is cured by irradiating ultraviolet rays through the surface plate 13 '(d). Then, the resin-made microlens array can be manufactured by peeling the ultraviolet curable resin 14 'from the mold and the surface plate 13' (e).

Further, by using the UV curable resin 14 ′ as a mold without using it as a microlens array, by repeating the steps of FIGS. A lens array can be manufactured. In addition, when using the surface of a resist or resin as a type | mold, the metal thin film or a dielectric thin film can be formed in these surfaces, the surface can be hardened, and the durability of a type | mold can also be increased. As the metal to be used, Cu, Al, Ni, Au and the like are appropriate, and as the dielectric to be used, SiNx, SiO ₂ , Al ₂ O ₃ , Ta ₂ O ₅ , TiO _{2 and the} like are appropriate.

  Also, a microlens formed as shown in FIG. 1 or a microlens formed by subjecting it to a solvent vapor treatment is electroformed to produce a replica, and this is used as a mold to form a resin. A plurality of microlens arrays made of resin can be produced by molding.

  An example of this is shown in FIG. In FIG. 4, as shown in FIG. 4C, a mold having a resist 12 in which the shape of a microlens array is formed on a substrate 11 is used as a mold (a). The Ni layer 15 is plated on the resist 12 by electroless plating, vapor deposition, or sputtering, and Ni electroforming is performed using the Ni layer 15 as an electrode to manufacture a Ni replica 16. Then, using this replica 16 as a mold, as shown in FIGS. 3C to 3E, an ultraviolet curable resin is injected between the mold and a transparent surface plate using a dispenser or the like. After pressing, the ultraviolet curable resin is cured by irradiating ultraviolet rays through a surface plate, and then the cured ultraviolet curable resin is peeled off from the mold and the surface plate to produce a resin microlens array. be able to.

  The above-described mold uses the resist 12 on which the microlens array shape is formed as a master of the mold, but in addition to this, the shape of the resist 12 is transferred to the substrate 11 to form the microlens array shape. The substrate 11 may be a mold master. By using this substrate 11 as a master of a mold, a master with a long life can be obtained.

  A resist microlens (array) having a lens diameter of 380 μm (effective diameter of 340 μm) and a SAG amount of 1 μm was manufactured. Using a positive resist, coating was performed at a rotation speed of 1800 rpm so that the resist thickness was 2 μm. After prebaking at 90 ° C. for 15 minutes, 12 simple circular pattern binary masks (corresponding to 5a to 5f in FIG. 1 are 5 in FIG. 1, but in this embodiment, the number of divisions is increased to 12 And then using an i-line stepper. The exposure time for the first mask (displayed in order from the smallest ring diameter) is 20 msec, the exposure time for the second mask is 40 msec, and the exposure time for the i-th mask is (20 * i) msec.

  The error of the resist shape obtained as a result is shown in FIG. 5 (comparative example).

  On the other hand, after developing, after performing three types of whole surface uniform exposure with exposure times of 31 msec, 56 msec, and 81 msec, the difference between the resist shape obtained as a result of development and the target shape is shown in FIG. It shows in FIG. 7, FIG. In any case, the shape of the microlens was measured with a stylus shape measuring machine.

  As a result, it can be seen that as the uniform exposure time for the entire surface becomes longer, the shape error becomes smaller, and in particular, the uneven protrusions seen in the peripheral edge portion become smaller. This is presumably because the shape error due to the level difference is reduced as a result of the uniform exposure on the entire surface.

It is a figure which shows the example of embodiment in the case of manufacturing a photoresist spherical surface microlens. It is a figure which shows the example of the method of smoothing the surface of a resist by the solvent vapor method. It is a figure which shows the method of manufacturing a type | mold and manufacturing resin-made microlenses using this type | mold. It is a figure which shows the method of manufacturing a replica and shape | molding resin using this as a type | mold, and manufacturing the several microlens array which consists of resin. It is a figure which shows the resist shape error at the time of not performing whole surface uniform exposure. It is a figure which shows a resist shape error at the time of performing the whole surface uniform exposure of the exposure time of 31 msec. It is a figure which shows a resist shape error at the time of performing the whole surface uniform exposure of exposure time 56msec. It is a figure which shows a resist shape error at the time of performing the whole surface uniform exposure of exposure time 81msec. It is a figure which shows the example of the manufacturing method of the conventional microlens.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Curved surface, 3 ... Surface shape, 4 ... Resist, 5a-5f ... Mask, 5g ... Mask for whole surface exposure, 6 ... Substrate, 7 ... Resist, 8 ... Petri dish, 9 ... Solvent, 10 ... Solvent vapor , 11 ... substrate, 12 ... resist, 13 ... surface plate, 14 ... ultraviolet curable resin, 15 ... Ni layer, 16 ... replica

Claims (5)

A method of manufacturing a microlens formed from a stepped pattern that approximates a concave shape, a convex shape, or a concave-convex shape, a resist is applied on a substrate, and a region having the same height in the stepped pattern, Each of the masks is exposed using one mask, and after the exposure using these masks is completed, the entire exposure area is subjected to batch exposure with an equal exposure amount, and then the resist is developed. A method of manufacturing a microlens. The method for manufacturing a microlens according to claim 1, wherein after developing the resist, the resist and the substrate are simultaneously etched to remove the resist, and the shape formed in the resist is changed to the substrate. A method for producing a microlens, comprising a step of transferring to a microlens. The shape of the lens is approximated to a concave shape, a convex shape, or a stepped pattern that approximates a concave and convex shape, and the method according to claim 1 is used to manufacture a microlens having the stepped shape resist, A method of manufacturing a microlens comprising the step of smoothing the stepped portion by exposing the resist to an atmosphere of a solvent vapor that dissolves the resist. 4. The method of manufacturing a microlens according to claim 3, wherein after the stepped portion of the resist is smoothed, the resist and the substrate are simultaneously etched to remove the resist, and the resist is formed on the resist. A method of manufacturing a microlens, comprising a step of transferring a shape which has been transferred to the substrate. A microlens mold manufacturing method in which the microlens according to claim 1 is replaced with a microlens manufacturing mold.

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