JP2010197821A - Method of producing lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a lens by which a desired lens shape can be easily formed. <P>SOLUTION: In a method of producing a lens array 1, a liquid repellent layer 12 having liquid repellency to a lens liquid material 1B is formed on a substrate 10 in a region D2 except a lens forming region (a region D1). Then the lens liquid material 1B is applied onto the substrate 10 and the lens liquid material 1B is selectively stuck to an exposed surface (the region D1) of the substrate 10 by the liquid repellency of the liquid repellent layer 12. Further in the region D1, a surface shape of the lens liquid material 1B becomes hemispherical owing to surface tension which the lens liquid material 1B has. Successively the lens liquid material 1B is calcined at predetermined temperature to form the lens which has a predetermined shape and is made of a predetermined material in the region D1 on the substrate 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a lens used for an on-chip lens, a lens array, or the like.

  Conventionally, a registry flow method is well known as a method for manufacturing a lens (for example, Patent Documents 1 to 4). In the method of Patent Document 1, first, a photosensitive resin (for example, a photoresist) serving as a lens material is formed on a glass substrate, and then the photoresist is patterned into a columnar shape or the like using a photolithography method. Thereafter, the patterned photoresist is reflowed by heating to a temperature exceeding its softening point. Thereby, a photoresist can be shape | molded in the shape (henceforth only convex shape) which has a hemispherical convex surface. However, in this method, since the photoresist molded into a convex shape functions as a lens, it is necessary to select a material that not only functions as a lens but also has photosensitivity. Therefore, it is not desirable because the range of material selection is narrowed.

  On the other hand, in the methods of Patent Documents 2 to 4, a base layer made of a lens material is formed, a convex photoresist is formed on the base layer by the same procedure as described above, and then dry etching is performed. The shape of the resist is transferred to the underlayer. Thereby, the underlayer is molded into a convex shape corresponding to the shape of the photoresist to be a lens. In this method, since it is not necessary to select a lens material having photosensitivity, a general material such as glass or resin can be used.

JP 61-67003 A JP 07-174903 A Japanese Patent Laid-Open No. 03-148173 Japanese Patent No. 3355874 Japanese Patent No. 3330655

  However, in the methods of Patent Documents 2 to 4, a difference in etching rate tends to occur between the photoresist material and the material of the underlayer (lens material such as glass or resin) during dry etching. For this reason, it is necessary to optimize various etching conditions according to the constituent materials of the photoresist and the underlayer, and there is a problem that a desired lens shape cannot be easily formed.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a lens manufacturing method capable of easily forming a desired lens shape.

  The lens manufacturing method of the present invention includes a step of forming a liquid repellent layer in a region excluding a lens forming region on a substrate, a step of applying a lens liquid material on the substrate on which the liquid repellent layer is formed, And a step of subjecting the lens liquid material on the material to a heat treatment.

  In the method for producing a lens of the present invention, a liquid repellent layer is first formed in a region excluding the lens formation region on the substrate, and then a lens liquid material is applied on the substrate. At this time, the lens liquid material selectively adheres to the lens formation region on the substrate due to the liquid repellency of the liquid repellent layer, and the surface shape becomes hemispherical due to the surface tension of the lens liquid material. By subjecting the lens liquid material thus formed on the substrate to heat treatment, a lens having a shape corresponding to the hemisphere due to the surface tension is formed.

  According to the method for manufacturing a lens of the present invention, the lens liquid material is applied on the base material after the liquid repellent layer is formed in the area excluding the lens forming area on the base material. It can be formed to be hemispherical in the lens formation region. Thereafter, a lens having a shape corresponding to the hemisphere can be formed by heat-treating the lens liquid material on the substrate. In other words, since the lens shape is formed by utilizing the liquid repellency of the liquid repellent layer and the surface tension of the lens liquid material, it can be easily obtained as compared with the case where the lens shape is formed by transfer using dry etching. It becomes possible to form the lens shape.

It is sectional drawing showing schematic structure of the lens array which concerns on one embodiment of this invention. FIG. 3 is a cross-sectional view illustrating a method of manufacturing the lens array illustrated in FIG. 1 in order of steps. FIG. 3 is a cross-sectional view illustrating a process following FIG. 2. FIG. 4 is a cross-sectional view illustrating a process following FIG. 3. FIG. 5 is a cross-sectional view illustrating a process following FIG. 4. 3 is a diagram illustrating a cross-sectional shape of a lens in the lens array according to Embodiment 1. FIG. 6 is a cross-sectional view illustrating a schematic configuration of a lens array according to Modification 1. FIG. FIG. 8 is a cross-sectional view illustrating a method of manufacturing the lens array illustrated in FIG. 7 in order of steps. FIG. 9 is a cross-sectional diagram illustrating a process following the process in FIG. 8. FIG. 10 is a cross-sectional diagram illustrating a process following the process in FIG. 9. FIG. 11 is a cross-sectional diagram illustrating a process following the process in FIG. 10. 6 is a diagram illustrating a cross-sectional shape of a lens in a lens array according to Example 2. FIG. 10 is a cross-sectional view illustrating a schematic configuration of a transmissive liquid crystal panel according to Application Example 1. FIG. 10 is a cross-sectional view illustrating a schematic configuration of an image sensor according to application example 2. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.

(1) Embodiment: After coating a patterned lens fluid material liquid repellent layer, Example (2) Modification of forming lens (SiO ₂₎ by firing lens fluid material in an oxidizing atmosphere 1: Lens Example of forming a metal layer in a region excluding the formation region (3) Modification 2: Example of forming a lens (Si) by firing a lens liquid material in a reducing atmosphere (4) Application example 1: Turning on the lens Example of application to a transmissive liquid crystal panel as a chip lens (5) Application example 2: Example of application of the above lens as an on-chip lens to an image sensor

<Embodiment>
[Configuration of Lens Array 1]
FIG. 1 shows a cross-sectional configuration of a lens array (lens array 1) according to an embodiment of the present invention. The lens array 1 is a two-dimensional array of a plurality of lenses 1 </ b> A on a substrate 10. The substrate 10 is made of a transparent substrate such as quartz or non-alkali glass. The lens 1 </ b> A is a convex lens having a hemispherical convex surface, and is formed separately from the substrate 10 in a region D <b> 1 (lens formation region) on the substrate 10. The lens 1A includes, for example, silicon dioxide (SiO ₂ ).

[Method for Manufacturing Lens Array 1]
(1. Cleaning of substrate 10)
The lens array 1 can be manufactured, for example, as follows. That is, first, the substrate 10 is washed with an alkaline cleaning solution, and then washed with pure water and dried. After that, the surface of the substrate 10 is subjected to, for example, UV ozone treatment to remove organic substances on the surface of the substrate 10.

(2. Formation of adhesion layer 11)
Next, as illustrated in FIG. 2A, the adhesion layer 11 is formed over the substrate 10. The adhesion layer 11 is for enhancing the adhesion of the liquid repellent layer 12 described later to the substrate 10. As the adhesion layer 11, for example, a silane coupling agent or the like can be used. Examples of the silane coupling agent include KBM-603 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. The material of the adhesion layer 11 may be selected appropriately according to the material of the substrate 10 and the thickness is about 2 nm or less.

  As a method for forming such an adhesion layer 11, for example, a vapor phase method or a spin coating method can be used. When the spin coating method is used, a material obtained by diluting the above material with an organic solvent such as ethyl lactate is applied on the substrate 10, and then the substrate 10 is heated on a hot plate at 120 ° C. for 5 minutes, for example. In the case of using the vapor phase method, for example, after the glass bottle containing the above material and the substrate 10 are placed in a sealed container, the container is placed in a heating oven in an environment of atmospheric pressure and 120 ° C. Leave for about 12 hours. Thereby, a monomolecular layer of about 2 nm or less is formed as the adhesion layer 11 on the surface of the substrate 10. Since the adhesion layer 11 is a very thin layer compared to the liquid repellent layer 12, the influence on the lens liquid material 1B due to the provision of the adhesion layer 11 is negligible.

(3. Patterning of liquid repellent layer 12 (creation of template 10A))
Next, as illustrated in FIG. 2B, the liquid repellent layer 12 is formed over the entire surface of the adhesion layer 11. As the liquid repellent layer 12, a material having liquid repellency (hereinafter simply referred to as liquid repellency) with respect to a lens liquid material 1B described later, for example, an amorphous fluororesin can be used. Examples of the amorphous fluororesin include CYTOP (trade name) manufactured by Asahi Glass Co., Ltd. The thickness of the liquid repellent layer 12 may be appropriately set according to the size and shape of the lens to be formed.

  As a method for forming such a liquid repellent layer 12, various coating methods such as a spin coating method and a dip coating method can be used. When the spin coating method is used, the material is diluted with a solvent and then applied onto the adhesion layer 11. Thereafter, the applied liquid repellent layer 12 is baked while raising the temperature to 50 ° C., 80 ° C., and 200 ° C., for example. In this way, the liquid repellent layer 12 is formed over the entire surface of the adhesion layer 11. Here, using Cytop (trade name) as the liquid repellent layer 12 makes it easy to obtain a desired film thickness. Further, by using this CYTOP (trade name), it becomes possible to perform a dry etching process in a process described later, and the liquid repellency can be restored by performing a heat treatment even after the photoresist is peeled off. However, the material of the liquid repellent layer 12 is not limited to this CYTOP (trade name), and for example, a resin used for an ink jet bank or the like, specifically, polyimide or the like may be used.

  Subsequently, as shown in FIG. 2C, a photoresist film 13 is formed over the entire surface of the liquid repellent layer 12 by using, for example, a spin coat method. However, before applying the photoresist film 13, it is desirable to subject the surface of the liquid repellent layer 12 to dry etching using, for example, oxygen plasma. By this dry etching, the surface of the liquid repellent layer 12 is roughened to such an extent that the subsequent process is not affected, and the photoresist film 13 can be easily formed.

  Thereafter, as shown in FIG. 3A, the photoresist film 13 is patterned. Specifically, the photoresist film 13 formed on the entire surface of the liquid repellent layer 12 is opened in a region D1 serving as a lens formation region through steps such as exposure, development, and post-baking using a photomask. Patterning is performed so as to form.

  Subsequently, as shown in FIG. 3B, the substrate 10 having the patterned photoresist film 13 is subjected to dry etching using, for example, oxygen plasma. As a result, the liquid repellent layer 12 and the adhesion layer 11 are sequentially removed in the region D1 that becomes the opening of the photoresist film 13, and the surface of the substrate 10 is exposed.

  Thereafter, as shown in FIG. 3C, the photoresist film 13 is removed using a resist stripping solution. In this way, the liquid repellent layer 12 is formed in a region (region D2) on the substrate 10 excluding the region D1. However, after removing the photoresist film 13, for example, heat treatment is performed at 120 ° C. for about 10 minutes. Thereby, the liquid repellency of the liquid repellent layer 12 can be restored. As described above, the template 10A in which the liquid repellent layer 12 is formed in the region D2 on the substrate 10 is obtained.

(4. Application of lens liquid material 1B)
Next, as shown in FIG. 4A, the lens liquid material 1B is applied onto the formed template 10A. The lens liquid material 1B is a liquid material that can be applied onto the template 10A, and is a material that generates a lens material by, for example, heat treatment in a subsequent process. The lens material finally obtained is, for example, silicon dioxide or silicon (Si). In the present embodiment, the case where silicon dioxide is generated from the lens liquid material 1B described below will be described.

As the lens liquid material 1B, for example, a material containing a silane compound having photopolymerization property or thermal polymerization property can be used. Examples of such silane compounds include those having one cyclic structure, specifically, cyclopentasilane (Si ₅ H ₁₀ ), cyclohexasilane, cyclotetrasilane, cyclotrisilane, and the like. Also, those having two cyclic structures, specifically 1,1′-bicyclobutasilane, 1,1′-bicyclopentasilane, 1,1′-bicyclohexasilane, 1,1′-bicycloheptasilane, etc. Is mentioned. Alternatively, as the lens liquid material 1B, among the silane compounds as described above, a silicon compound in which a part of hydrogen atoms bonded to Si is substituted with a halogen atom or a SiH ₃ group may be used.

  The lens liquid material 1B contains the silane compound as described above in a polymerized state, that is, as polysilane. This polysilane is oxidized by a heat treatment in a later step to become silicon dioxide. In addition to the polysilane, the lens liquid material 1B is desirably mixed with a non-polymerized silane compound. Thereby, while improving the applicability | paintability of the lens liquid material 1B, it becomes possible to form various lens shapes by adjusting the mixing ratio of the superposed | polymerized thing and the non-polymerization thing. As the mixing ratio, for example, the polymerized silane compound is about 20 or less with respect to the non-polymerized silane compound (referred to as 1). Depending on the target lens shape, an organic solvent such as toluene may be further added.

When such a lens liquid material 1B is applied onto the template 10A, the slider 110 is used in order from one side of the template 10A in a reducing atmosphere such as argon (Ar) or nitrogen (N ₂ ). The lens liquid material 1B is dropped. At this time, the lens liquid material 1B has a difference in wettability to the surface of the liquid repellent layer 12 and the surface of the substrate 10, that is, due to the liquid repellency of the liquid repellent layer 12 and the adhesion of the lens liquid material 1B to the substrate 10. 10 selectively adhere to the exposed surface (region D1). In the region D1, the surface shape is hemispherical due to the surface tension of the lens liquid material 1B. Thereby, as shown in FIG. 4B, hemispherical lens liquid material 1B is formed in each of a plurality of regions D1 on template 10A.

  The method of applying the lens liquid material 1B is not limited to the above method, and for example, an ink jet method or the like may be used.

(5. Firing of lens liquid material 1B)
Next, heat treatment is performed on the template 10A coated with the lens liquid material 1B. Specifically, first, the non-polymerized silane compound in the lens liquid material 1B is decomposed and volatilized by baking at about 200 ° C. to 260 ° C. for about 30 minutes. As a result, the surface shape of the remaining polysilane becomes the final lens shape. Thereafter, the polysilane is oxidized by baking at about 260 ° C. to 400 ° C. for about 30 minutes in an oxygen atmosphere to form silicon dioxide that can function as a lens. Thereby, as shown in FIG. 5, the template 10A in which the lens 1A is formed in the region D1 is obtained.

(6. Removal of liquid repellent layer 12 and adhesion layer 11)
Finally, the liquid repellent layer 12 and the adhesion layer 11 on the template 10A are removed using, for example, a dry etching method. Thus, the lens array 1 shown in FIG. 1 is completed. Depending on the application of the lens array 1, even if the liquid repellent layer 12 and the adhesion layer 11 remain in the region D2, they may not be removed if there is no optical problem.

  As described above, in the present embodiment, the liquid repellent layer 12 is formed in the region D2 excluding the lens formation region (region D1) on the substrate 10, and then the lens liquid material 1B is applied onto the substrate 10. . At this time, the lens liquid material 1B can be formed to be hemispherical in the region D1 due to the liquid repellency of the liquid repellent layer 12 and the surface tension of the lens liquid material 1B. Thereafter, the lens 1A can be formed in the region D1 by firing the lens liquid material 1B.

  At this time, the lens shape of the lens 1A includes the material of the substrate 10 and the surface shape and area of the region D1, the material and thickness of the liquid repellent layer 12, the material constituting the lens liquid material 1B, its application amount, polymerization, and non-polymerization. It can be determined by a ratio or the like.

  Here, a lens forming method using the conventional registry flow method will be described. In this conventional method, a photoresist formed on a base layer made of a lens material is molded into a desired shape, and the shape of this photoresist is transferred to the base layer by a dry etching method as a lens shape. However, in this method, since the etching rate differs between the photoresist and the underlayer, it is necessary to optimize the etching conditions according to the photoresist material and the material of the underlayer (lens material), and the desired shape Is difficult to form.

  On the other hand, in the present embodiment, as described above, the lens mainly utilizes the liquid repellency of the liquid repellent layer 12, the adhesion of the lens liquid material 1B to the substrate 10, and the surface tension of the lens liquid material 1B. 1A is formed. That is, since the lens shape is formed mainly by selecting each material such as the substrate 10, the liquid repellent layer 12, and the lens liquid material 1 </ b> B without going through a conventional etching process, a desired lens shape is easily formed. It becomes possible.

  Incidentally, Patent Document 5 proposes a method of forming a lens made of silicon dioxide by patterning amorphous silicon formed in a vacuum into a desired shape and then baking it. Specifically, the amorphous silicon after patterning is first baked at 1200 ° C. in a nitrogen atmosphere to form a lens shape, and then baked at 1000 ° C. in an oxygen atmosphere using saturated water vapor to thereby obtain silicon dioxide. Is generated. However, when such a method is used, a heat treatment at a high temperature is required. For example, it is difficult to form an on-chip lens for a device having no heat resistance, and materials that can be used as a substrate are limited. End up.

  With respect to this point as well, in this embodiment, as described above, the temperature when firing the lens liquid material 1B is about 400 ° C. or lower, and processing at a lower temperature is possible compared to the method of Patent Document 5 above. is there. For this reason, the lens array 1 can be suitably used as an on-chip lens for a device having no heat resistance.

Example 1
As the lens liquid material 1B, for example, a silane compound can be used. Here, as an example of the present embodiment (Example 1), the lens array 1 was manufactured by the same procedure as described above using cyclopentasilane as the lens liquid material 1B. However, quartz was used as the substrate 10, and the adhesion layer 11 was formed by a vapor phase method using KBM-603 (trade name). Further, the liquid repellent layer 12 was formed by diluting CYTOP with a solvent so as to have a film thickness of 200 nm by using a spin coating method with a rotation speed of 3500 rpm. Before the photoresist film 13 is formed, dry etching using oxygen plasma (oxygen flow rate: 180 sccm, power: 300 W, oxygen gas pressure: 3 Pa, processing time: 15 seconds) is performed on the surface of the liquid repellent layer 12. gave. As the photoresist film 13, a positive resist AZ1500 (20 cp) (trade name) manufactured by Clariant Japan Co., Ltd. was used, and the film thickness was about 1.4 μm. The dry etching conditions after patterning of the photoresist film 13 were an oxygen flow rate of 180 sccm, an electric power of 300 W, an oxygen gas pressure of 3 Pa, and a processing time of 120 seconds. In addition, after the photoresist film 13 was peeled off, the liquid repellent property of the liquid repellent layer 12 was restored by subjecting the liquid repellent layer 12 to a heat treatment at 120 ° C. for 10 minutes. As the lens liquid material 1B, a mixture of cyclopentasilane polymerized by irradiating ultraviolet rays having a wavelength of 300 nm or less for about 30 minutes and non-polymerized cyclopentasilane in a ratio of about 20: 1 was used. Such a lens liquid material 1B was baked in an oxygen atmosphere to obtain a lens 1A made of silicon dioxide. FIG. 6 shows a cross-sectional shape of the lens 1 </ b> A obtained in Example 1.

  Next, modified examples (modified examples 1 and 2) of the manufacturing method of the lens array of the above embodiment will be described. In the following, the same components as those in the above embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

<Modification 1>
FIG. 7 illustrates a cross-sectional configuration of a lens array (lens array 2) according to the first modification.

[Configuration of Lens Array 2]
The lens array 2 is formed by two-dimensionally arranging a plurality of lenses 1A on a substrate 10 as in the above embodiment. However, in this modification, the metal layer 15 as a light shielding film is formed in the region D2 excluding the region D1 corresponding to the lens 1A. The metal layer 15 is a single layer film or a laminated film made of a light-shielding material such as aluminum (Al), chromium (Cr), nickel (Ni), molybdenum (Mo), silver (Ag), titanium (Ti), and the like. The thickness is, for example, 50 nm or more. The material and film thickness of the metal layer 15 may be appropriately set according to the required light shielding performance.

[Method for Manufacturing Lens Array 2]
The lens array 2 can be manufactured, for example, as follows. That is, first, in the same manner as in the above embodiment, after cleaning the substrate 10, the organic substance on the surface of the substrate 10 is removed by performing, for example, UV ozone treatment. After that, as shown in FIG. 8, the metal layer 15 is formed over the entire surface of the substrate 10 by using, for example, a sputtering method or a vacuum evaporation method. Subsequently, as shown in FIG. 9A, the adhesion layer 11, the liquid repellent layer 12, and the photoresist film 13 are formed in this order on the metal layer 15 in the same manner as in the above embodiment. As in the above embodiment, after the liquid repellent layer 12 is formed and before the photoresist film 13 is formed, the surface of the liquid repellent layer 12 is subjected to a heat treatment process and dry etching. It is desirable to go through a roughening process. Thereafter, as shown in FIG. 9B, the photoresist film 13 is patterned in the same manner as in the above embodiment.

  Next, as shown in FIG. 10A, dry etching is performed on the substrate 10 having the patterned photoresist film 13 in the same manner as in the above embodiment. As a result, the liquid repellent layer 12 and the adhesion layer 11 are sequentially removed in the region D1 that becomes the opening of the photoresist film 13, and the surface of the metal layer 15 is exposed. Subsequently, as shown in FIG. 10B, the substrate 10 after dry etching is subjected to, for example, wet etching to remove the metal layer 15 and expose the surface of the substrate 10 in the region D1. . As an etchant used for wet etching, an etchant that can etch the metal layer 15 may be selected. For example, when aluminum is used as the metal layer 15, a mixed acid aluminum solution (trade name) manufactured by Wako Pure Chemical Industries, Ltd., and when chromium is used, chromium such as ETCH-1 (trade name) manufactured by Omiya Kasei. Each etchant can be used. As described above, the adhesion layer 11, the liquid repellent layer 12, the photoresist film 13, and the metal layer 15 may be etched stepwise, but may be removed by one etching. Thereafter, in the same manner as in the above embodiment, after the photoresist film 13 is peeled off, the liquid repellent property of the liquid repellent layer 12 is restored by applying heat treatment to the liquid repellent layer 12. In this way, a template 20A (not shown in FIG. 10B) is produced.

  Subsequently, as shown in FIG. 11A, the lens liquid material 1B is attached to the region D1 on the substrate 10 on the template 20A in the same manner as in the above embodiment. Thereafter, as shown in FIG. 11B, the lens liquid material 1B is baked to form the lens 1A by applying heat treatment to the template 20A in the same manner as in the above embodiment. Thus, the lens array 2 shown in FIG. 7 is completed.

  As in this modification, the metal layer 15 as a light shielding film may be formed in the region D2 excluding the region D1 corresponding to the lens 1A. Even in this case, the same effect as the above embodiment can be obtained. Further, by providing the metal layer 15, for example, light incident on the region D2 other than the lens 1A, such as external light and stray light, can be blocked. If such a light shielding film is retrofitted to the lens array, it is necessary to align the light shielding film and the lens. For this reason, in the case of retrofitting, a method of patterning a light shielding film using a photoresist on the back surface of the substrate, a method of forming a light shielding film using an inkjet method, or the like is used. However, in the method using a photoresist, it is necessary to expose the photoresist through the substrate, so that it is necessary to select a material transparent to ultraviolet rays as the substrate. In the method using the ink jet method, there is a possibility that the light shielding film material ejected from the ink jet adheres to the lens surface.

  On the other hand, in this modification, the lens liquid material 1B is applied to the template 20A in which the metal layer 15 together with the liquid repellent layer 12 is formed in the region D2 on the substrate 10, and then the lens liquid material 1B is baked. Thus, the lens 1A is formed. That is, the metal layer 15 can be formed in the region D2 on the substrate 10 before forming the lens 1A. Therefore, in this modification, unlike the case where the light shielding film is retrofitted to the lens array, the usable substrate material is not narrowed, and the light shielding film material (metal material in this modification) may adhere to the lens portion. Nor.

(Example 2)
As an example (Example 2) of this modified example, a lens array 2 was manufactured by the same procedure as described above. However, aluminum having a film thickness of 75 nm was used as the metal layer 15, and a mixed acid aluminum liquid (trade name) was used as the etchant for the metal layer 15. The other process conditions were the same as in Example 1 above. FIG. 12 shows a cross-sectional shape of the lens 1A obtained in the second embodiment.

<Modification 2>
The manufacturing method of the lens array according to this modification has the same steps as the manufacturing method of the lens array 1 of the above embodiment, except for the firing process of the lens liquid material 1B. That is, first, the lens liquid material 1B is applied onto the template 10A in the same manner as in the above embodiment, and then the lens liquid material 1B is baked at about 200 ° C. to 260 ° C. for about 30 minutes. Thereby, the non-polymerized silane compound is volatilized to form a lens shape of polysilane. Thereafter, in this modification, the formed polysilicon is baked at about 350 ° C. to 450 ° C. for about 30 minutes in a reducing atmosphere such as nitrogen or argon, thereby generating amorphous silicon (amorphous silicon). However, in this modification, it is desirable to use a single crystal silicon substrate as the substrate 10.

  As described above, the firing of the lens liquid material 1B is not limited to the oxygen atmosphere as described in the embodiment and the first modification, and may be performed in a reducing atmosphere. By firing the lens liquid material 1B in a reducing atmosphere, a lens made of amorphous silicon that can function as a lens can be formed.

  Further, polysilicon (polycrystalline silicon) may be generated by solid-phase growth of amorphous silicon formed as described above. Specifically, after the lens liquid material 1B is baked in a reducing atmosphere to generate amorphous silicon, the liquid repellent layer 12 and the adhesion layer 11 are removed. Thereafter, the produced amorphous silicon may be further baked at 600 ° C., for example. Thereby, the lens comprised from the polysilicon can be formed. Since the lens is made of polysilicon, infrared rays can be transmitted particularly efficiently, so that a lens array suitable for a field using infrared rays can be manufactured.

  Next, application examples (application examples 1 and 2) of the manufacturing method of the lens array 1 according to the above embodiment will be described. The following application examples 1 and 2 are examples of so-called on-chip lenses in which the lens 1A in the lens array 1 is formed directly on the device.

<Application example 1>
FIG. 13 illustrates a cross-sectional configuration of the transmissive liquid crystal panel 3 according to Application Example 1. The transmissive liquid crystal panel 3 is used in, for example, a liquid crystal projector and transmits light from a light source (not shown) and performs enlarged display on a screen or the like. The transmissive liquid crystal panel 3 includes a plurality of liquid crystal display elements (display pixels) arranged in a matrix and a lens 1A formed on the light emission side of the plurality of display pixels. In each display pixel, a liquid crystal layer 35 is sealed between a pair of substrates 30 and 40 made of, for example, a quartz substrate. A TFT 31 as a drive element is disposed on the substrate 30, and an insulating film 32 and a planarizing layer 33 are formed on the TFT 31. A pixel electrode 34 connected to the TFT 31 by a wiring (not shown) is provided on the planarizing layer 33, and a common electrode 36 is provided on the substrate 40 so as to face the pixel electrode 34. A cell gap between the substrate 30 and the substrate 40 is held by a spacer 37.

  In such a configuration, the substrate 30 is on the light source side (light incident side), and the substrate 40 is on the display side (light emitting side). Among these, the lens 1A is formed directly on the substrate 40. This lens 1A can be formed on the substrate 40 in the same manner as in the above embodiment. In this case, the lens 1A may be formed after sealing the liquid crystal layer 35 with the substrates 30 and 40, or the lens 1A is formed in advance on the substrate 40 before the liquid crystal layer 35 is sealed. The liquid crystal layer 35 may be sealed using the substrate 40 with 1A formed.

  In this transmissive liquid crystal panel 3, when light is incident from the substrate 30 side, the incident light is transmitted through the substrate 40 and the lens 1 </ b> A in order after each transmitted pixel is controlled for display. The By passing through the lens 1A, the display light is enlarged and projected on a screen or the like. Thus, the lens 1A can be suitably used as an on-chip lens having functions such as a fly-eye lens and an integrator lens of a liquid crystal projector.

<Application example 2>
FIG. 14 illustrates a cross-sectional configuration of the image sensor 4 according to Application Example 2. The image sensor 4 includes a plurality of imaging pixels arranged in a matrix on a substrate 50 made of, for example, silicon (Si), and a lens 1A is provided on the light receiving side of these imaging pixels. This imaging pixel is a solid-state imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide Semiconductor). In each imaging pixel, a photodiode 41 is disposed on the substrate 50, and a color filter layer 43 (a red filter 43R, a green filter 43G, and a blue filter 43B) is provided on the photodiode 41 via a wiring layer. It has been. Lenses 1A are formed on the respective light incident surfaces of the red filter 43R, the green filter 43G, and the blue filter 43B. In this application example, since the lens 1A is formed directly on the color filter, the heat treatment in the oxygen atmosphere (second heat treatment) is preferably performed at a temperature of about 350 ° C. or lower.

  In the image sensor 4, the lens 1 </ b> A is provided on the light receiving side, so that incident light is efficiently collected for each imaging pixel, passes through the red filter 43 </ b> R, the green filter 43 </ b> G, and the blue filter 43 </ b> B, respectively. Light is received by the diode 41. In this way, the lens 1A of the above embodiment may be formed directly on the light receiving surface of the image sensor 4.

  The lens 1A as an on-chip lens is not limited to the transmissive liquid crystal panel 3 of the application example 1 and the image sensor 4 of the application example 2, and can be applied to other devices. For example, the lens 1A can also be used as a fine convex lens structure provided on a light emitting surface of a light source such as a light emitting diode (LED) or a laser. Further, it can be used for an optical coupler, a solar battery, a 3D display capable of stereoscopic display by a multi-view system, and the like.

  Further, the metal layer 15 described in the first modification may be provided between the plurality of lenses 1A.

  Although the present invention has been described with reference to the embodiment and the modifications, the present invention is not limited to the above-described embodiment and the like, and various modifications can be made. For example, in the above-described embodiments and the like, the method for manufacturing a lens array having a plurality of lenses has been described as an example. However, the method for manufacturing a lens of the present invention is not limited to a lens array, and a single lens is provided on a substrate. The present invention can also be applied when manufacturing a single lens arranged.

  In the above-described embodiment and the like, the case where the adhesion layer 11 is formed between the substrate 10 and the liquid repellent layer 12 is described as an example. However, the adhesion layer 11 is not necessarily formed. When the adhesion layer 11 is not used, a template can be formed by the following method, for example. That is, grade CYTOP having adhesion to the substrate 10 is used, or the following method is used. Using quartz as the substrate 10, first, a layer made of chromium (Cr) having a thickness of, for example, 50 nm is formed on the surface of the substrate 10 by using, for example, a vacuum deposition method or a sputtering method. Subsequently, a portion corresponding to the lens formation region in the formed chrome layer is selectively removed by etching using, for example, a photolithography method. Thereafter, the substrate 10 obtained by selectively removing the chromium layer is dipped in a surface treatment agent having a perfluoroalkyl group, for example, KP-801M (trade name: manufactured by Shin-Etsu Chemical Co., Ltd.) for about 1 minute and dried. Thereby, the surface of the chromium layer and the surface of the substrate 10 exposed from the chromium layer become liquid repellent. Thereafter, for example, by applying UV ozone treatment or the like from the back surface side of the substrate 10, the liquid repellency of only the lens forming portion is removed. In this way, a template can be formed.

  Furthermore, in the above-described embodiment and the like, after the photoresist film 13 is peeled off, UV ozone treatment, ashing treatment, or the like is performed on the exposed surface of the template substrate 10, that is, the surface of the substrate 10 in the region D1 that is the lens formation region. You may make it give. Thereby, the surface of the board | substrate 10 can be activated with respect to the lens liquid material 1B.

  DESCRIPTION OF SYMBOLS 1, 2 ... Lens array, 1A ... Lens, 1B ... Lens liquid material, 3 ... Transmission type liquid crystal panel, 4 ... Image sensor, 10 ... Substrate, 11 ... Adhesion layer, 12 ... Liquid-repellent layer, 13 ... Photoresist film, 15 ... Metal layer, 10A, 20A ... Template.

Claims (12)

Forming a liquid repellent layer in an area excluding the lens forming area on the substrate;
Applying a lens liquid material on the substrate on which the liquid repellent layer is formed;
Applying a heat treatment to the lens liquid material on the substrate. Examples lens liquid material, manufacturing method of lens according to claim 1 using a material that produces a silicon dioxide (SiO ₂₎ or silicon (Si) by the heat treatment. The method for manufacturing a lens according to claim 2, wherein a material containing a silane compound is used as the lens liquid material. The lens manufacturing method according to claim 3, wherein a material containing a polymerized silane compound and a non-polymerized silane compound is used as the lens liquid material. The method for manufacturing a lens according to claim 3, wherein cyclopentasilane (Si ₅ H ₁₀ ) is used as the silane compound. The method for manufacturing a lens according to claim 2, wherein silicon dioxide is generated by performing heat treatment on the lens liquid material in an oxidizing atmosphere. The lens manufacturing method according to claim 2, wherein the lens liquid material is subjected to a heat treatment in a reducing atmosphere to generate amorphous silicon. The method for manufacturing a lens according to claim 7, wherein the amorphous silicon is further heat treated to generate polycrystalline silicon. The method for manufacturing a lens according to claim 1, wherein in the step of forming the liquid repellent layer, an adhesion layer is formed between the base material and the liquid repellent layer. The method for manufacturing a lens according to claim 1, wherein in the step of forming the liquid repellent layer, a light shielding layer is formed between the base material and the liquid repellent layer. The method for manufacturing a lens according to claim 10, wherein an adhesion layer is formed between the light shielding layer and the liquid repellent layer. The method for manufacturing a lens according to claim 1, wherein the liquid repellent layer is removed after heat-treating the lens liquid material.

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