JP5700209B2 - PHOTOELECTRIC CONVERSION DEVICE AND ITS MANUFACTURING METHOD, OPTICAL WAVEGUIDE FORMING COMPOSITION AND CURED PRODUCT - Google Patents

Description

  The present invention relates to a photoelectric conversion element, a method for producing the same, an optical waveguide forming composition, and a cured product thereof.

  A photoelectric conversion device such as a solid-state imaging device mounted on a digital camera, a mobile phone, or the like includes a plurality of two-dimensional light receiving units (photoelectric conversion mechanisms) such as a charge coupled device (CCD) and a metal oxide semiconductor (MOS). It has the structure arranged in. Such a photoelectric conversion element has been required to increase the number of pixels. That is, in the photoelectric conversion element, each pixel is increasingly miniaturized. Accordingly, the amount of light received per unit pixel of the photoelectric conversion element has become very small.

  If the amount of light received by the light receiving unit is insufficient, the quality of the captured image is degraded. For this reason, a method for increasing the amount of received light per pixel has been proposed. For example, it has been proposed to provide a lens for condensing light at the light receiving portion of the photoelectric conversion element, or to provide an optical waveguide for the element. As an example of forming an optical waveguide, for example, Patent Document 1 describes that an optical waveguide is formed of a material having a high refractive index. This document discloses the use of a composite material of a highly transparent resin and metal oxide particles having a high refractive index such as titanium oxide as such a high refractive index material.

  Patent Document 2 discloses an attempt to increase the refractive index of an optical member using a certain kind of polyamic acid and its imidized polymer.

JP 2008-091744 A JP 2008-274234 A

  However, since the pixels of the photoelectric conversion element have become very small, the dimensions of the optical waveguide have also become very small. That is, the optical waveguide has a light receiving surface with a small area and a long waveguide path (a shape with a large aspect ratio).

  Therefore, when a resin composition containing metal oxide particles as described above is used as the material of the optical waveguide, the material is uniformly distributed over the entire opening for the optical waveguide in the process of forming the optical waveguide during manufacturing. It is getting harder to fill.

  Further, for example, if the refractive index of the resin itself forming the optical waveguide can be increased by the resin disclosed in Patent Document 2, the embedding property is considered to be good. However, since the polyimide resin disclosed in the document is a relatively low molecular weight substance, there is a concern that solvent resistance and heat resistance may be insufficient. Therefore, when a color filter, an antireflection film, a flattening film, or the like is formed on the upper layer of the waveguide section, there is a risk of mixing and whitening with these, or coloring due to heating in the solder reflow process, which may impair the light collecting property. was there.

  The present invention has been made in view of the above problems, and one of the objects according to some embodiments thereof is to provide a photoelectric conversion element having an optical waveguide with good solvent resistance and heat resistance. . Another object of some embodiments of the present invention is to provide a method for producing a photoelectric conversion element having an optical waveguide with good solvent resistance and heat resistance. Furthermore, one of the objects according to some embodiments of the present invention is to provide a composition suitable for an optical waveguide of a photoelectric conversion element and a cured product thereof.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

  Application Example 1 One aspect of a photoelectric conversion element according to the present invention includes a substrate, a photoelectric conversion unit formed above the substrate, and an optical waveguide unit formed above the photoelectric conversion unit. The optical waveguide part contains a cured product of a composition containing sulfur and a polyimide having a refractive index at 633 nm of 1.60 or more and a crosslinking agent.

  In the present specification, the term “upper” means, for example, “form another specific thing (hereinafter referred to as“ B ”)“ above ”a specific thing (hereinafter referred to as“ A ”)”, etc. Used. In this specification, unless otherwise specified, the case where B is directly formed on A, the case where B is formed on A via another, and the upper part of A, unless otherwise specified. In which B is formed.

  Application Example 2 In Application Example 1, the cured product may include a structure represented by the following general formula (1).

(In the general formula (1), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently An integer of 0 to 4 is shown, R represents a tetravalent organic group, and n represents an integer of 1 to 4.)

  Application Example 3 In Application Example 2, R may be a tetravalent aliphatic or alicyclic hydrocarbon having 4 to 12 carbon atoms.

  Application Example 4 In any one of Application Examples 1 to 3, the crosslinking agent is at least selected from an alkyl etherified product of methylol melamine, an alkyl etherified product of methylol melamine condensate, and a polyfunctional vinyl ether compound. One kind may be sufficient.

  Application Example 5 In any one of Application Examples 1 to 4, the optical waveguide portion has a columnar shape, and one end in the longitudinal direction of the columnar shape is optically connected to the photoelectric conversion unit. You may connect to.

  Application Example 6 In Application Example 5, in the cross section parallel to the longitudinal direction of the optical waveguide portion, the length in the longitudinal direction is the maximum of the lengths in the direction perpendicular to the longitudinal direction. It may be 0.5 times or more and 10 times or less.

  Application Example 7 One aspect of a method for manufacturing a photoelectric conversion element according to the present invention includes a step of forming a photoelectric conversion unit above a substrate, and a step of forming an interlayer insulating layer so as to cover the photoelectric conversion unit. A composition comprising a step of forming a hole penetrating the upper surface of the photoelectric conversion part in the interlayer insulating layer, a polymer including a structure represented by the following general formula (1) in the hole, and a crosslinking agent: And a step of curing the composition.

(In the general formula (1), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently An integer of 0 to 4 is shown, R represents a tetravalent organic group, and n represents an integer of 1 to 4.)

  Application Example 8 In Application Example 7, R may be a tetravalent aliphatic or alicyclic hydrocarbon having 4 to 12 carbon atoms.

  [Application Example 9] In Application Example 7 or Application Example 8, the composition is represented by the general formula (1) when the total amount of the components excluding the organic solvent is 100% by mass. The polymer including the structure may be contained in an amount of 80% by mass or more and 99% by mass or less, and the crosslinking agent may be contained in an amount of 1% by mass or more and 20% by mass or less.

  [Application Example 10] One embodiment of the composition for forming an optical waveguide according to the present invention includes a polymer having a structure represented by the following general formula (1), a crosslinking agent, and an organic solvent capable of uniformly dissolving them. When the total amount of the components excluding the organic solvent is 100% by mass, the polymer containing the structure represented by the general formula (1) is 80% by mass or more and 99% by mass or less, and the crosslinking agent is 1% by mass or more. 20% by mass or less is contained.

(In the general formula (1), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently An integer of 0 to 4 is shown, R represents a tetravalent organic group, and n represents an integer of 1 to 4.)

  Application Example 11 In Application Example 10, the polymer including the structure represented by the general formula (1) may be a polymer having a structure represented by the following general formula (2).

(In the general formula (2), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently R represents an integer of 0 to 4, R represents a tetravalent organic group, n represents an integer of 1 to 4, l and m represent an integer of 1 to 100,000 in total l + m, and l: m is 50:50 to 100: 0.)

  [Application Example 12] In Application Example 10 or Application Example 11, R may be a tetravalent aliphatic or alicyclic hydrocarbon having 4 to 12 carbon atoms.

  [Application Example 13] One aspect of the cured product according to the present invention is obtained by curing a polymer containing a structure represented by the following general formula (1) and a crosslinking agent.

(In the general formula (1), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently An integer of 0 to 4 is shown, R represents a tetravalent organic group, and n represents an integer of 1 to 4.)

  In the photoelectric conversion element according to the present invention, the optical waveguide portion contains a cured product having a structure based on a tetracarboxylic dianhydride, an aromatic diamine containing a sulfur atom, and a crosslinking agent. Therefore, it has an optical waveguide with good solvent resistance and heat resistance, the flatness and filling properties of the optical waveguide portion are good, and the manufacturing is easy. Moreover, since the optical waveguide part contains a sulfur atom and an aromatic ring, the refractive index is large. Thereby, the photoelectric conversion element concerning this invention has favorable condensing efficiency. According to the method for manufacturing a photoelectric conversion element according to the present invention, the optical waveguide part has a step of filling a polymer containing a structure represented by the general formula (1) and a composition containing a crosslinking agent. Therefore, a photoelectric conversion element having an optical waveguide with good solvent resistance and heat resistance can be easily manufactured.

The schematic diagram of the cross section of the principal part of the photoelectric conversion element 100 concerning an example of embodiment. The schematic diagram which expanded the cross section of the principal part of the photoelectric conversion element 100 concerning an example of embodiment. The schematic diagram of the process of forming an interlayer insulation layer among the manufacturing processes of the photoelectric conversion element 100 concerning an example of embodiment. The schematic diagram of the process of forming a hole in an interlayer insulation layer among the manufacturing processes of the photoelectric conversion element 100 concerning an example of embodiment. The schematic diagram of the process of filling a composition among the manufacturing processes of the photoelectric conversion element 100 concerning an example of embodiment. The schematic diagram of the process of removing the optical-waveguide part formed on the interlayer insulation layer among the manufacturing processes of the photoelectric conversion element 100 concerning an example of embodiment.

  Hereinafter, preferred embodiments of the present invention will be described. Embodiment described below demonstrates an example of this invention. In addition, the present invention is not limited to the following embodiments, and includes various modifications that are implemented within a range that does not change the gist of the present invention. Note that not all of the configurations described in the following embodiments are indispensable constituent requirements of the present invention.

  Examples of the photoelectric conversion element according to the present invention include a charge coupled device (CCD) and a MOS type imaging device. In the following embodiment, a photoelectric conversion element 100 including a CCD is illustrated.

1. Photoelectric Conversion Device FIG. 1 is a schematic cross-sectional view of a main part of a photoelectric conversion device 100 according to an example of the embodiment. FIG. 2 is an enlarged schematic view of the cross section of the main part of the photoelectric conversion element 100.

  The photoelectric conversion element 100 of this embodiment includes a substrate 10, a photoelectric conversion unit 20, and an optical waveguide unit 30.

1.1. Substrate The substrate 10 becomes a base of the photoelectric conversion element 100. The substrate 10 has a flat shape, a film shape, a sheet shape, or the like. The substrate 10 may be a stacked body of a plurality of substrates. The board | substrate 10 may be comprised including a semiconductor substrate and a wiring board, for example. A photoelectric conversion unit 20 (described later), a register, and the like can be formed on the substrate 10. Further, the substrate 10 may include a transistor (for example, TFT), a control IC, a wiring layer, and the like. FIG. 1 illustrates an example in which the photoelectric conversion unit 20 is formed on the substrate 10.

  The material of the substrate 10 is not particularly limited, and inorganic materials such as metal, glass, silicon, and gallium arsenide, and polymer materials such as (meth) acrylic resin, polyimide resin, alicyclic olefin resin, polycarbonate, polyethylene terephthalate, and the like Can be illustrated. The substrate 10 may be a laminate of a plurality of layers. For example, the substrate 10 may include a reflective layer that reflects light. If the substrate 10 is a semiconductor substrate such as a silicon substrate or a GaAs substrate, the photoelectric conversion unit 20 can be easily formed in the substrate 10.

1.2. Photoelectric Conversion Unit The photoelectric conversion unit 20 is formed above the substrate 10. The photoelectric conversion unit 20 may be formed so as to be embedded in the upper surface of the substrate 10. In the photoelectric conversion element 100 of this embodiment, the photoelectric conversion unit 20 is formed on the upper surface side of the substrate 10.

  The shape of the photoelectric conversion unit 20 is not particularly limited, and may be an oval, a circle, a rectangle, a square, or the like in plan view. The area of the photoelectric conversion unit 20 in a plan view can be appropriately designed according to the design of the resolution and the like of the photoelectric conversion element 100. For example, the length of one side in a square shape can be 100 nm or more and 10 μm or less. . A plurality of photoelectric conversion units 20 can be formed on the substrate 10. The number of photoelectric conversion units 20 formed on the substrate 10 is appropriately selected according to the design such as the resolution of the photoelectric conversion element 100 and is not particularly limited. Moreover, the thickness etc. of the photoelectric conversion part 20 are not specifically limited.

  The photoelectric conversion unit 20 is a part that converts light into an electrical signal (photosensor) or a part that converts electricity into light, and a known photoelectric conversion element such as a photodiode can be applied. Further, for example, the photoelectric conversion unit 20 can be configured by a pn junction or the like in which the substrate 10 is a semiconductor substrate and regions having different conductivity types are formed on the surface thereof. Furthermore, the photoelectric conversion unit 20 may be formed including other components such as a register.

  The wavelength range of the electromagnetic wave (light) detected by the photoelectric conversion unit 20 is not particularly limited, but is, for example, in the range of 300 nm to 1100 nm. The photoelectric conversion unit 20 can typically detect visible light and convert it into an electrical signal.

1.3. Optical waveguide section 1.3.1. Shape of Optical Waveguide Part, etc. The optical waveguide part 30 is formed above the photoelectric conversion part 20. The optical waveguide portion 30 is formed by optically connecting to the photoelectric conversion portion 20. In addition, as long as the optical waveguide unit 30 is optically connected to the photoelectric conversion unit 20, the optical waveguide unit 30 may be connected to the photoelectric conversion unit 20 via another member (for example, an optical member such as a lens). Note that “optically connected” refers to a state in which light can be transmitted.

  One of the functions of the optical waveguide unit 30 is to collect light incident on the photoelectric conversion element 100 with respect to the photoelectric conversion unit 20 when the photoelectric conversion element is a light receiving element. On the other hand, when the photoelectric conversion element is a light emitting element, it is possible to increase the extraction efficiency of light emitted from the photoelectric conversion element 100 with respect to light emitted from the photoelectric conversion unit 20. Therefore, it is desirable that the optical waveguide unit 30 be formed of a material having a higher refractive index than that of other adjacent members. The refractive index of the optical waveguide portion is preferably 1.60 or more, and more preferably 1.65 or more. In the present invention, “refractive index” means a refractive index at 633 nm at 25 ° C. As a result, light can be confined in the optical waveguide section 30 and the light collection efficiency on the photoelectric conversion section 20 can be further increased. Details of the material of the optical waveguide portion 30 will be described later.

  The optical waveguide unit 30 is provided corresponding to each photoelectric conversion unit 20. The optical waveguide part 30 has a columnar shape. The optical waveguide unit 30 is arranged so that one end in the longitudinal direction of the columnar shape is optically connected to the photoelectric conversion unit 20. Although it does not specifically limit as a concrete shape of the optical waveguide part 30, For example, it can be set as a column shape, prismatic shape, a truncated cone, a truncated pyramid etc.

  In the photoelectric conversion element 100 of this embodiment, since the shape of the optical waveguide part 30 is a columnar shape, the optical waveguide part 30 can be arranged with high density (the resolution of the photoelectric conversion element 100 can be increased), and It is possible to ensure insulation in the thickness direction (longitudinal direction of the optical waveguide portion 30). In addition, since the optical waveguide portion 30 has a columnar shape, it is easy to collect light incident from the outside of the photoelectric conversion element 100 onto the photoelectric conversion portion 20.

  In the example of FIG. 1, the optical waveguide portion 30 has a truncated cone shape with a smaller cross section on the photoelectric conversion portion 20 side. Furthermore, the upper surface or the lower surface of the optical waveguide portion 30 may have a convex shape or a concave shape. In this way, the function of an optical lens can be imparted to the optical waveguide portion 30. The uneven shape in this case can be freely designed in consideration of the optical path of incident light.

  In addition, in the cross section parallel to the longitudinal direction, the length of the longitudinal direction of the optical waveguide portion 30 is not less than 0.5 times and not more than 10 times the maximum length in the direction perpendicular to the longitudinal direction. More preferably. By making the optical waveguide part 30 into such a shape, the resolution of the photoelectric conversion element 100 can be further increased, and insulation in the longitudinal direction of the optical waveguide part 30 can be ensured.

  The optical waveguide unit 30 may be disposed alone as long as it is disposed above the photoelectric conversion unit 20, for example, an interlayer formed above the substrate 10 like the photoelectric conversion element 100 of the present embodiment. A hole 42 may be provided in the insulating layer 40, and the optical waveguide portion 30 may be formed inside the hole 42. (See FIG. 2). In this way, for example, the manufacture of the optical waveguide part 30 can be facilitated.

The refractive index of the optical waveguide part 30 is preferably higher than the refractive index around it. In the case of forming the interlayer insulating layer 40, in order to increase the light collection efficiency to the photoelectric conversion unit 20, as the material of the interlayer insulating layer 40, SiO ₂ having a refractive index of about 1.4 to 1.5 or a refractive index Formed with SiO ₂ materials such as BPSG (borophosphosilicate glass), PSG (phosphosilicate glass), SOG (spin-on-glass), and SiON (silicon oxynitride) materials with a thickness of about 1.4 to 1.5 It is preferred that When the interlayer insulating layer 40 is formed of silicon oxide (SiO ₂ ), it can be formed by, for example, a thermal oxidation method or a CVD (Chemical Vapor Deposition) method.

  Moreover, the photoelectric conversion element 100 of this embodiment may have an on-chip lens 50 for condensing on the optical waveguide part 30, as shown in FIG. In the illustrated example, the on-chip lens 50 is provided above the optical waveguide unit 30, but may be provided below. A plurality of on-chip lenses 50 may be provided.

1.3.2. Material of optical waveguide section 1.3.2.1. Composition The optical waveguide part 30 is formed with the cured | curing material of the composition which contains a polyimide which contains sulfur and the refractive index in 633 nm is 1.60 or more, and a crosslinking agent. The polyimide can be obtained, for example, by condensing a tetracarboxylic dianhydride and an aromatic diamine compound containing sulfur, and further imidizing.

<1> Tetracarboxylic dianhydride As the tetracarboxylic dianhydride used as a raw material for obtaining the polyimide, a compound represented by the following general formula (3) can be used.

[In General Formula (3), R represents a tetravalent organic group. ]
In general formula (3), R may have a structure classified into at least one of aliphatic, alicyclic and aromatic. The tetracarboxylic dianhydride is preferably an aliphatic or alicyclic tetracarboxylic dianhydride, in which R is aliphatic or alicyclic, from the viewpoint of enhancing the transparency of the resulting cured product. Carboxylic dianhydrides are more preferred.

Specific examples of the aliphatic and alicyclic tetracarboxylic dianhydrides include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 4,10-dioxatricyclo [6.3.1.0 ^2,7 ] dodecane-3,5,9,11-tetraone, , 2,4,5-cyclohexanetetracarboxylic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1, 3,3a, 4,5,9b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2, 5-Dioxotetrahydrofura ) -3-Methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, etc. And tetracarboxylic dianhydrides. Among these, 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 4,10-dioxatricyclo [6.3.1 .0 ^2,7] dodecane -3,5,9,11- tetraone, 5- (2,5-dioxo-tetrahydrofuranyl Le) methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride and 1 , 3,3a, 4,5,9b-hexahydro-5-tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione is more preferred, 2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 4,10-dioxatricyclo [6.3.1.0 ^2,7 ] Dodecane-3,5,9,11-tetraone 1,2,4,5-cyclohexanetetracarboxylic dianhydride is more preferable from the viewpoint of enhancing the transparency of the cured product.

  Specific examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl Sulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′- Biphenyl ether tetracarboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilane tetracarboxylic dianhydride, 2 , 3,4,5-tetrahydrofurantetracarboxylic dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4'-bis (3,4-dica Boxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 4,4 ′-(hexafluoroisopropylidene) bis (phthalic acid) dianhydride 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene- Aromatics such as bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride Mention may be made of tetracarboxylic dianhydrides. Among these, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic dianhydride, 4 , 4 '-(Hexafluoroisopropylidene) bis (phthalic acid) dianhydride and 3,3', 4,4'-biphenyltetracarboxylic dianhydride are more preferable because the cured product has a high refractive index.

  Further, from the viewpoint of obtaining a cured product having a higher refractive index, it is more preferable that the tetracarboxylic dianhydride contains a sulfur atom. Examples of tetracarboxylic dianhydrides containing sulfur atoms include 4,4 '-[p-thiobis (phenylene-sulfanyl)] diphthalic dianhydride.

  For example, the structure based on tetracarboxylic dianhydride is polymerized in the state of tetracarboxylic acid (non-anhydride of tetracarboxylic dianhydride exemplified above) to form a structure based on polyamic acid, and then It may be formed by performing a dehydration reaction using an imidization catalyst.

  Polyamic acid formed by polymerization in the state of tetracarboxylic acid can be chemically imidized or thermally imidized. Examples of the imidization catalyst used in the chemical imidization include an acetic anhydride-pyridine mixed solution. Moreover, an acetic anhydride-triethylamine mixed solution, trifluoroacetic anhydride, and dicyclohexylcarbodiimide can also be used. Furthermore, you may use the photo-acid generator or photobase generator which is a compound which generate | occur | produces an acid or a base by light irradiation as an imidation catalyst. Examples of the photobase generator include carbamate type photobase generators.

<2> Aromatic diamine containing sulfur atom Examples of the aromatic diamine containing a sulfur atom used as a raw material for obtaining the polyimide include compounds represented by the following general formula (4).

In General formula (4), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently The integer of 0-4 is shown, n shows the integer of 1-4. ]
In the general formula (4), it is more preferable from the viewpoint of the refractive index that a is 0 (that is, no substituent) or R ¹ is a cyano group and a is 1. Moreover, n is more preferably an integer of 2 to 4 from the viewpoint of refractive index.

  Examples of the diamine represented by the general formula (4) include 4,4 ′-(p-phenylenedisulfanyl) dianiline, 1,3-bis (4-aminophenylsulfanyl) benzene, 1,3-bis ( 4-aminophenolsulfanyl) 5-cyanobenzene, 4,4′-thiobis [(p-phenylenesulfanyl) aniline], 4,4′-bis (4-aminophenylsulfanyl) -p-dithiophenoxybenzene and the like. Of these, 4,4′-thiobis [(p-phenylenesulfanyl) aniline] is more preferable from the viewpoint of refractive index.

<3> Other monomer components The polyimide used in this embodiment may contain a structure derived from another monomer. For example, the polyimide may include a structure based on a diamine other than an aromatic diamine containing a sulfur atom. Examples of such diamines include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane, 4,4′-diaminodiphenyl sulfide, and 4,4′-. Diaminodiphenyl sulfone, 4,4′-diaminodiphenyl ether, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, 3,4′-diaminodiphenyl ether, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-Aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-a Nophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 9,9-bis (4-aminophenyl) fluorene, 4,4′-methylene- Bis (2-chloroaniline), 2,2 ′, 5,5′-tetrachloro-4,4′-diaminobiphenyl, 2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl 3,3′-dimethoxy-4,4′-diaminobiphenyl, 4,4 ′-(p-phenylenediisopropylidene) bisaniline, 4,4 ′-(m-phenylenediisopropylidene N) Bisaniline, aromatic diamine having a hetero atom such as diaminotetraphenylthiophene; 1,1-metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, Octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylenediethylenediamine, tricyclo Mention may be made of aliphatic or alicyclic diamines such as [6.2.1.0 ^2,7 ] -undecylenedimethyldiamine.

  When the structure based on the diamine is introduced into the polyimide, the structure based on the diamine is preferably 30% by mass or less, more preferably 20% or less when the total monomer unit of the polyimide is 100% by mass. In order to adjust the refractive index of the cured product, the blending amount can be appropriately adjusted.

<4> Polyimide The polyimide used for the composition of this embodiment is a polyimide containing sulfur and having a refractive index at 633 nm of 1.60 or more. When the polyimide contains sulfur, the refractive index of the obtained polyimide increases, and as a result, the refractive index of the optical waveguide portion 30 can be increased. Moreover, it is preferable that the refractive index of a polyimide is 1.65 or more. In addition, the number average molecular weight of polyimide measured by gel permeation chromatography is the workability when forming the optical waveguide portion 30 (easiness of application when made into a solution), particularly to the hole where the optical waveguide portion 30 is formed. The embedding property is preferably 2,000 or more and 10,000 or less, and more preferably 3,000 or more and 8,000 or less.

  The polyimide obtained from tetracarboxylic dianhydride and an aromatic diamine containing a sulfur atom can have a repeating unit represented by the following general formula (1).

In General Formula (1), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently R represents an integer of 0 to 4, R represents a tetravalent organic group, and n represents an integer of 1 to 4. ]
The polymer having the structure represented by the general formula (1) can be obtained, for example, by reacting the above-exemplified aromatic diamine containing a sulfur atom with the above-described tetracarboxylic dianhydride.

  The reaction between the aromatic diamine containing a sulfur atom and tetracarboxylic dianhydride can be carried out in an aprotic organic solvent such as N-methyl-2-pyrrolidone. A polymer of the general formula (1) can be obtained by stirring and mixing an aromatic diamine compound containing a sulfur atom and tetracarboxylic dianhydride. Further, for example, an aromatic diamine containing a sulfur atom may be dissolved in an organic solvent, and tetracarboxylic dianhydride may be added thereto and stirred and mixed. The reaction is carried out, for example, at a temperature of 100 ° C. or lower, preferably 80 ° C. or lower and normal pressure. You may carry out under pressure or pressure reduction as needed. Although reaction time changes with diamine compounds and acid dianhydride to be used, an organic solvent, reaction temperature, etc., it is the range of 1 to 24 hours, for example. The polymer thus obtained can be imidized by heating. At this time, a known imidation catalyst such as acetic anhydride-pyridine mixed solution, acetic anhydride-triethylamine mixed solution, trifluoroacetic anhydride, dicyclohexylcarbodiimide or the like can also be used.

  The polyimide having a repeating unit represented by the general formula (1) may be a polymer represented by the following general formula (2).

In General formula ^(2), R 1, a, R, n is as defined for formula (1), the molar ratio (l: m) is 50: 50 to 100: 0. ]
Here, the molar ratio (l: m) represents the imidization ratio of the polymer represented by the general formula (2), and the imide skeleton (polyimide moiety) (l) and the amide acid skeleton (polyamic acid). (Polyamide acid site) The molar ratio with (m) is shown. That is, the molar ratio (l: m) of 50:50 to 100: 0 represents that the imidation ratio is 50% or more and 100% or less in the polymer represented by the general formula (2). ing. In other words, when the molar ratio (l: m) is 50:50 to 100: 0, the polymer represented by the general formula (2) has an amic acid content of 0% or more and 50% or less. It represents something. The solvent tolerance of the optical waveguide part 30 can be improved as the imidation ratio of the polymer represented by the general formula (2) is 50% or more and 100% or less. For the above reason, the imidation ratio of the polymer represented by the general formula (2) is preferably 70% or more and 100% or less. Here, in this embodiment, the polyimide means an imidized product of polyamic acid, and all the bonds may not be imidized.

  The reaction temperature when performing imidization can be set to 70 to 150 ° C., for example. The reaction time is preferably in the range of 1 to 24 hours. When performing thermal imidation, it can carry out by making the substance which has a structure based on a polyamic acid react at 150-250 degreeC for 1 to 24 hours in a high boiling-point solvent.

  In addition, the content rate of the amic acid (amic acid) in the polymer represented by General formula (2) can be calculated | required by NMR (nuclear magnetic resonance method), for example.

  Any of the polyimides having the repeating units represented by the general formula (1) and the general formula (2) is a polymer obtained from a tetracarboxylic dianhydride and an aromatic diamine containing a sulfur atom. By making it react with the above-mentioned crosslinking agent, the hardened material which forms an optical waveguide part can be obtained.

<5> Crosslinking agent Examples of the crosslinking agent include polyfunctional compounds such as polyfunctional melamine compounds, urea compounds, guanamine compounds, phenolic compounds, epoxy compounds, isocyanate compounds, and polybasic acids. Moreover, the crosslinking agent may be a single type of these compounds or a combination of two or more types.

  Among these cross-linking agents, melamine compounds having two or more methylol groups and / or alkoxylated methyl groups in the molecule are known because they are relatively excellent in storage stability but can be cured at a relatively low temperature. preferable. Among these melamine compounds, hexamethyl etherified methylol melamine compounds, hexabutyl etherified methylol melamine compounds, methylbutyl mixed etherified methylol melamine compounds, methyl etherified methylol melamine compounds, butyl etherified methylol melamine compounds, etc. Alkyl etherified products and alkyl etherified products of methylol melamine condensates are more preferred because they can achieve both reactivity and storage stability.

  On the other hand, as the crosslinking agent, ethylenically unsaturated compounds such as polyfunctional ether compounds having a plurality of ethylenically unsaturated groups such as vinyl groups, polyfunctional (meth) acrylate compounds having a plurality of ethylenically unsaturated groups such as vinyl groups, etc. A polyfunctional compound having a plurality of groups can also be used. Examples of polyfunctional compounds having a plurality of ethylenically unsaturated groups include alkyl divinyl ethers such as 1,4-butanediol divinyl ether, cyclohexane dimethanol divinyl ether, diethylene glycol divinyl ether, and diethylene glycol divinyl ether as polyfunctional vinyl ether compounds, Examples of the polyfunctional (meth) acrylate include (meth) acrylic esters such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

  The amount of the crosslinking agent in the present embodiment is preferably 0.1% or more and 30% or less, and more preferably 1% or more and 20% or less, when the entire composition excluding the organic solvent is 100%. If a crosslinking agent exists in this range, solvent tolerance can be provided to the hardened | cured material obtained.

<6> Organic solvent The organic solvent used in the composition is selected so that the polymer containing the structure represented by the general formula (1) and the crosslinking agent can be uniformly dissolved.

  Examples of such an organic solvent include an aprotic organic solvent. Examples of the aprotic organic solvent include N-methyl-2-pyrrolidone (NMP), N, N-dimethylformamide (DMF), cyclohexanone (CHN), N, N-dimethylacetamide (DMAc), γ-butyrolactone ( GBL) and the like are preferable. Besides these, N, N-diethylacetamide, N, N-dimethoxyacetamide, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethyl] ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyrroline , Picoline, dimethyl sulfoxide, dimethyl sulfone, tetramethyl urea, hexamethyl phosphoramide, propylene glycol monomethyl ether (PGME), γ-butyrolactone (GBL), phenol, o-cresol, m-cresol, p-cresol, m- Cresolic acid, p-chlorofe Lumpur, mention may be made of anisole, benzene, toluene, and xylene. These organic solvents can be used alone or as a mixture of two or more.

  In the composition for forming the optical waveguide portion 30, the amount of the organic solvent added is 100 when the polymer having the structure represented by the general formula (1) and the crosslinking agent are 100 parts by mass. -9,900 parts by mass, preferably 150-1,900 parts by mass, more preferably 200-1,900 parts by mass. If the compounding quantity of the organic solvent with respect to the composition is within such a range, good coating can be performed. The organic solvent may be an organic solvent derived from the production of a polymer including the structure represented by the general formula (1).

1.3.2.2. Other Components The optical waveguide portion 30 of the present embodiment preferably contains 80% by mass or more, and more preferably 90% by mass or more of the above-described cured product with respect to the total mass of the optical waveguide unit 30. Therefore, the optical waveguide part 30 of this embodiment may contain substances other than the above-mentioned hardened | cured material in 20 mass% or less.

<Surfactant>
The optical waveguide unit 30 may contain a surfactant. The surfactant can be used to adjust the wettability and fluidity of the composition used when forming the optical waveguide portion 30. And after the optical waveguide part 30 is formed, you may contain in the optical waveguide part 30 with hardened | cured material.

  Examples of such surfactants include silicon-based surfactants and fluorine-based surfactants, and polydimethylsiloxane-based surfactants.

  Examples of silicon-based surfactants include, for example, SH28PA, DC57, DC190, Paintad 19, 54 (Toray Dow Corning, dimethylpolysiloxane polyoxyalkylene copolymer), SF8428 (Toray Dow Corning, dimethyl) Polysiloxane polyoxyalkylene copolymer (containing side chain OH)), Silaplane FM-4411, FM-4421, FM-4425, FM-7711, FM-7721, FM-7725, FM-0411, FM-0421, FM-0425, FM-DA11, FM-DA21, FM-DA26, FM-0711, FM-0721, FM-0725, TM-0701, TM-0701T (manufactured by Chisso Corporation), UV3500, UV3510, UV3530 (Bicchemy Japan) BY) 6-004 (manufactured by Dow Corning Toray Silicone Co., Ltd.), (manufactured by Wako Pure Chemical) VPS-1001, Tego Rad2300,2200N (manufactured by Tego Chemie), and the like.

  Examples of the fluorosurfactant include Megafac F-114, F410, F411, F450, F493, F494, F443, F444, F445, F446, F470, F471, F472SF, F474, F475, R30, F477, F478, F479, F480SF, F482, F483, F484, F486, F487, F553, F172D, F178K, F178RM, ESM-1, MCF350SF, BL20, R08, R61, R90 (manufactured by Dainippon Ink & Chemicals, Inc.) can be mentioned.

  As one of the functions of the surfactant, for example, in the manufacture of the photoelectric conversion element 100, the optical waveguide portion 30 is formed by applying a composition containing a raw material for forming the cured product by spin coating. In some cases, a uniform coating film is formed.

  When the surfactant is contained in the optical waveguide part 30, the content is 0.001 to 10% by mass, preferably 0.01 to 5% by mass, based on the total amount of the components excluding the organic solvent in the composition. More preferably, it exists in the range of 0.01-2 mass%. When the blending amount of the surfactant is within the above range, the coating property of the composition containing the raw material for forming the cured product becomes good.

<Others>
The optical waveguide portion 30 may contain inorganic particles. Examples of the inorganic particles include titanium oxide, zirconium oxide, and aluminum oxide. Among these, the titanium oxide particles may be blended in order to adjust the refractive index of the optical waveguide portion 30. When inorganic particles are contained in the optical waveguide portion 30, for example, 0.001 to 10% by mass, preferably 0.01 to 5% by mass, more preferably 100% by mass based on the total amount of components excluding the organic solvent. Is in the range of 0.01 to 2% by mass.

  Further, the optical waveguide portion 30 may contain a resin such as polystyrene.

<Hardened product>
The cured product of the present embodiment is obtained by curing the above composition. Curing is performed by applying the composition to a substrate and then heating. The heating temperature at this time is room temperature to 300 ° C, preferably 30 to 250 ° C. Moreover, although heating time can be suitably changed in view of the size and shape of the cured product to be produced, it is usually 1 minute to 2 hours, preferably 3 minutes to 1 hour. At this time, it may be heated at a constant temperature or may be heated sequentially at different temperatures. By curing the above-described composition, a cured product including a structure represented by the following general formula (1) can be obtained.

  The refractive index of the cured product of this embodiment is preferably 1.60 or more, and more preferably 1.65 or more.

1.4. Other Configurations The photoelectric conversion element 100 according to this embodiment can include various other members. For example, the photoelectric conversion element 100 may include an in-layer lens, a transfer electrode, a light shielding film, a color filter, a planarization layer, an antireflection film, and the like.

1.5. Operational Effect, etc. In the photoelectric conversion element 100 according to the present embodiment, the optical waveguide unit 30 contains a cured product having a structure based on a tetracarboxylic dianhydride, an aromatic diamine containing a sulfur atom, and a crosslinking agent. Yes. Therefore, the solvent resistance and heat resistance of the optical waveguide portion 30 are good. Moreover, since the hardened | cured material contained in the optical waveguide part 30 with which the photoelectric conversion element 100 concerning this embodiment is provided has a sulfur atom and an aromatic ring, a refractive index is large. Thereby, the photoelectric conversion element 100 has good condensing efficiency to the photoelectric conversion unit 20.

2. Manufacturing Method of Photoelectric Conversion Element FIGS. 3 to 6 are schematic views of manufacturing steps of the photoelectric conversion element 100 which is an example of the present embodiment.

  The method for manufacturing a photoelectric conversion element according to the present invention includes a step of forming a photoelectric conversion portion above a substrate 10, a step of forming an interlayer insulating layer so as to cover the photoelectric conversion portion, and the photoelectric conversion element on the interlayer insulating layer. Forming a hole penetrating the upper surface of the conversion part, and filling the hole with a polymer containing at least a polymer represented by the following general formula (1) and a composition containing a crosslinking agent. .

(In the general formula (1), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently An integer of 0 to 4 is shown, R represents a tetravalent organic group, and n represents an integer of 1 to 4.)
Hereinafter, although each process is explained in full detail, in description of the above-mentioned photoelectric conversion element 100, about the member described, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  First, as shown in FIG. 3, the substrate 10 is prepared, and the photoelectric conversion unit 20 is formed above (upper surface) of the substrate 10. The photoelectric conversion unit 20 can be formed by a known method, for example, by doping the substrate 10 with impurities. Moreover, a charge transfer part etc. can be formed as needed simultaneously with or before or after the formation of the photoelectric conversion part 20. Further, after the photoelectric conversion unit 20 is formed, a transfer electrode, an antireflection film, and a light shielding film may be formed as necessary. Further, an insulating film other than the interlayer insulating layer 40 may be formed.

  Next, as illustrated in FIG. 3, an interlayer insulating layer 40 a is formed so as to cover the photoelectric conversion unit 20. The interlayer insulating layer 40 a may be formed to cover the photoelectric conversion unit 20 and the substrate 10. In the illustrated example, the interlayer insulating layer 40 a is formed to cover the photoelectric conversion unit 20 and the substrate 10. The interlayer insulating layer 40a can be formed by, for example, a spin coat method, a CVD method, or the like.

  Next, as shown in FIG. 4, a hole 42 penetrating from the upper surface of the interlayer insulating layer 40 to the upper surface of the photoelectric conversion unit 20 is formed in the interlayer insulating layer 40. The hole 42 has a shape corresponding to the outer shape of the optical waveguide portion 30. The hole 42 is formed above the photoelectric conversion unit 20. In the present embodiment, the hole 42 is formed through the interlayer insulating layer 40 so as to reach the photoelectric conversion unit 20, but is a recess formed in the interlayer insulating layer 40 that extends toward the photoelectric conversion unit 20. It may be. The hole 42 can be formed by photolithography or the like using an appropriate mask and etchant. The hole 42 can also be formed by a known method such as anisotropic dry etching or reactive dry etching.

  Next, as shown in FIG. 5, the hole 42 is filled with a composition containing sulfur and containing a polyimide having a refractive index of 1.60 or more at 633 nm and a crosslinking agent to form the optical waveguide portion 30a. Specifically, in this step, a method such as application using a liquid injection nozzle such as a dispenser, spray application such as an ink jet method, application by rotation such as spin coating, application by squeezing such as printing, or transfer may be used. it can.

  The composition used in this step may contain, for example, an organic solvent for adjusting the viscosity of the composition in addition to a polyimide containing sulfur and a refractive index at 633 nm of 1.60 or more, and a crosslinking agent. Good. The organic solvent used in the composition is as described above.

  In order to improve the solvent resistance of the cured product, an imidization catalyst can be blended in the composition. In that case, the compounding amount of the imidization catalyst with respect to the composition is 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, with respect to 100% by mass of the total component excluding the organic solvent. It is. When the above-mentioned imidation catalyst is used, a step of performing a curing treatment can be added as necessary. The curing process can be, for example, photocuring or heat curing.

  In this step, a particulate material may be added to the composition to be applied as long as the coating property and embedding property are not impaired.

  In this step, since such a composition is used, coating using a liquid injection nozzle such as a dispenser, spray coating such as an inkjet method, coating by rotation such as spin coating, coating by squeezing such as printing, or transfer, It is easy to fill the hole 42 without a gap. In this way, especially when the size of the optical waveguide portion 30 in the major axis direction is not less than 0.5 times and not more than 10 times the size of the optical waveguide portion 30 in the minor axis direction, the hole 42 is formed without gaps. Filling can be done very easily.

  Thereafter, as shown in FIG. 6, a step of removing the optical waveguide portion 30a (on the portion other than the hole 42) formed on the interlayer insulating layer 40 can be performed as necessary. This step can be performed by dry etching, wet etching, or the like. In the case where this step is performed, when no particulate matter is added to the coating film of the optical waveguide portion 30a, the etching rate such as dry etching or wet etching can be sufficiently increased.

  Next, for example, by providing a separately prepared microlens array above the interlayer insulating layer 40, the photoelectric conversion element 100 of this embodiment shown in FIG. 1 can be obtained.

  According to the method for manufacturing a photoelectric conversion element of the present embodiment, the optical waveguide has good condensing property to the photoelectric conversion portion, flatness of the optical waveguide portion, good filling property, and good solvent resistance and heat resistance and heat coloring property. It is possible to easily manufacture a photoelectric conversion element having

3. Examples and Comparative Examples Examples and Comparative Examples are shown below to describe the present invention more specifically, but they do not limit the scope of the present invention.

  In Examples and Comparative Examples, the embedding property of the composition containing the polymer represented by the general formula (1), the crosslinking agent, and the organic solvent into the holes, heat transparency, and solvent resistance were evaluated. That is, the following composition is applied to the following substrate, and various shapes of the member after drying, transparency after heat treatment (after curing), cracks after immersion in acetone, film loss, or the presence or absence of whitening evaluated.

  The examples and comparative examples model the optical waveguide formation process in the manufacture of photoelectric conversion elements, and this evaluation can evaluate the optical characteristics, solvent resistance, manufacturability, etc. of the optical waveguide portion. it can.

3.1. As the substrate 10, a silicon substrate was used. A SiO ₂ film having a thickness of 3 μm was formed on the upper surface of the silicon substrate by spin coating and baked. Then, the SiO ₂ film was etched to form a hole (through hole reaching the silicon substrate) having an opening diameter of 0.8 μm and a depth of 3 μm. Note that the refractive index of the SiO ₂ film is in the vicinity of 1.45. If the refractive index of the optical waveguide portion formed in the example or the like is high, the light condensing property in the photoelectric conversion element is realized.

3.2. Composition The composition of A thru | or L shown in Table 1 was prepared as a composition which forms hardened | cured material.

  In the table, the unit of the number is part by mass, but the compounding amount of the component excluding the solvent can be regarded as mass%.

  In Table 1, P-1 is BT-100 (1,2,3,4-butanetetracarboxylic dianhydride manufactured by Shin Nippon Chemical Co., Ltd.) as an acid dianhydride, and 3SDA (4,4) as a diamine. A polymer synthesized using '-thiobis [(p-phenylenesulfanyl) aniline]) is shown. 3SDA was synthesized by the method described in JP-A-2008-274234.

  In the preparation of P-1, first, dimethylacetamide (30 g) (hereinafter referred to as DMAc) was added to 3SDA (11.9 g, 27.5 mmol) in a reaction vessel equipped with a nitrogen introduction tube, and the mixture was completely dissolved by stirring at room temperature. I let you. Next, BT-100 (5.45 g, 27.5 mmol) and DMAc (10 g) were added, and the mixture was stirred at 40 ° C. for 4 hours. Next, after adding DMAc (110 g), acetic anhydride (2.81 g) and pyridine (2.18 g) were added as imidation catalysts, and the mixture was stirred at 110 ° C. for 5 hours to obtain a DMAc solution of P-1. . A predetermined amount of DMAc was removed by a vacuum distillation method to obtain a solution having a solid content concentration of 20%, and then a predetermined amount of γ-butyrolactone (hereinafter referred to as GBL) was added to obtain a solution having a solid content concentration of 10%. After this operation was repeated twice, the solid content concentration was again adjusted to 45% by a vacuum distillation method to obtain a PBL GBL solution. The imidation ratio of P-1 was 50%. That is, P-1 is a polymer having a structure represented by the general formula (2), and l: m is 50:50.

  In Table 1, P-2 indicates a polymer synthesized in the same manner as P-1 by increasing the amount of acetic anhydride and pyridine, which are imidation catalysts, from P-1. A PBL GBL solution was prepared in the same manner as P-1, except that acetic anhydride (5.61 g) and pyridine (4.35 g) were used. The imidation ratio of P-2 was 90%. That is, P-2 is a polymer having a structure represented by the general formula (2), and l: m is 90:10.

  In Table 1, P-3 shows the polymer which synthesize | combined by further increasing the acetic anhydride and pyridine which are imidation catalysts more than P-2. A PBL GBL solution was prepared in the same manner as P-1, except that acetic anhydride (8.43 g) and pyridine (6.54 g) were used. The imidation ratio of P-3 was 93%. That is, P-3 is a polymer having a structure represented by the general formula (2), and l: m is 93: 7.

  In addition, the imidation ratio of P-1 thru | or P-3 was calculated | required by calculating | requiring the content rate of an amic acid. Specifically, it was determined by measuring NMR (nuclear magnetic resonance method) of P-1 to P-3.

  In Table 1, P-4 was prepared as follows. First, N-methyl-2-pyrrolidone (80 g) (NMP) was added to bis (p-aminophenyl) ether (8.01 g, 40 mmol) (hereinafter referred to as ODA) in a reaction vessel equipped with a nitrogen introduction tube, And completely dissolved. Next, 1,2,3,4-cyclobutanetetracarboxylic dianhydride (hereinafter referred to as CBDA) (7.84 g, 40 mmol) and NMP (25 g) were added, and the mixture was stirred at room temperature for 24 hours. Of NMP was obtained.

  In Table 1, P-5 was prepared as follows. A polyamic acid was prepared in the same manner as P-1, except that 2,7-bis (4-aminophenylenesulfanyl) thianthrene (11.90 g, 25.71 mmol) and BT-100 (5.10 g, 25.76 mmol) were used. Obtained. Further, an imidization reaction and post-treatment were performed in the same manner as P-2 except that pyridine (6.11 g) and acetic anhydride (7.89 g) were used to obtain a PBL GBL solution. The imidation ratio was 91%. Here, 2,7-bis (4-aminophenylenesulfanyl) thianthrene is described in Macromolecules, Vol. 40, P4614, 2007.

  In Table 1, cross-linking agents X, Y, and Z are X: Cymel 303 (alkyl etherified product of methylol melamine condensate) manufactured by Nippon Cytec Industries, Ltd., Y: CHDVE (polyfunctional vinyl ether compound manufactured by Nippon Carbide Industries, Ltd.) ), Z; BDVE (polyfunctional vinyl ether compound) manufactured by Nippon Carbide Industries Co., Ltd.

  As the surfactant, a dimethylpolysiloxane-polyoxyalkylene copolymer (DC-190, manufactured by Toray Dow Corning Silicone) was used.

  The compositions A to L were diluted with a mixed solvent of cyclohexanone (CHN) and γ-butyrolactone (GBL), and the final compositions are shown in Table 1. The composition used for each Example and each comparative example is a composition in which the components excluding the above-mentioned solvent are 100 parts by mass, and the organic solvent is blended in parts by mass shown in Table 1.

3.3. Evaluation Method In each example and each comparative example, evaluation of embedding property, heat transparency, solvent resistance, and refractive index was performed as follows.

In any of the examples, a substrate in which a hole having an opening diameter of 0.8 μm and a depth of 3 μm was formed in the SiO ₂ film formed on the above-described silicon wafer was used.

  Evaluation of embedding property: The composition of each example and each comparative example was applied to the substrate by spin coating under the condition that the film thickness after the hole was embedded was 0.6 μm, and this was applied at 120 ° C. An evaluation sample was obtained by sequentially heating and drying for 1 minute at 180 ° C. for 3 minutes and 250 ° C. for 5 minutes. And after cut | disconnecting the board | substrate of each Example and each comparative example, respectively, the cross section of a hole is observed with a scanning electron microscope (SEM), and what has a void in a composition has favorable embedding property. In the table, a circle was given, and those in which voids were generated were marked with a x.

  Heat transparency evaluation: A sample was prepared by applying and drying a resin composition on a glass wafer in the same manner as in the embedding evaluation. Samples heated and dried sequentially at 120 ° C. for 1 minute, 180 ° C. for 3 minutes, and 250 ° C. for 5 minutes, and samples further heated at 265 ° C. for 5 minutes (265 ° C. in the table) 2 types) were prepared respectively. And about the coating film of each sample, a film thickness is measured with a stylus type film thickness meter, and the transmittance | permeability in 400 nm of the sample obtained using the ultraviolet visible spectrophotometer is measured. In the column of transmittance (400 nm), the film thickness and the transmittance measured at each temperature are described.

Evaluation of solvent resistance: A sample was prepared by applying and drying the composition in the same manner as in the evaluation of embedding property. The obtained sample was immersed in acetone for 5 minutes and then dried at 120 ° C. for 1 minute, and the appearance (whitening, cracks) and the film thickness remaining rate were determined to evaluate the solvent resistance. The solvent resistance is shown in Table 2 as ◯ when cracks are not recognized by visual evaluation, Δ when cracks are recognized by SEM observation, and x when cracks are clearly recognized visually. Further, Table 2 shows that no whitening was observed, and whitened that was white. The film thickness residual ratio was calculated by the following formula using the film thickness obtained by a stylus type film thickness meter before and after immersion in acetone and listed in Table 2.
Formula: Residual rate of film thickness (%) = 100 × film thickness after acetone immersion (μm) / film thickness before acetone immersion (μm)
Refractive index: Using a sample prepared in the same manner as the solvent resistance evaluation sample, the refractive index at a wavelength of 633 nm at 25 ° C. was determined by a prism coupler.

3.4. Evaluation Results Table 2 summarizes the evaluation results of each Example and each Comparative Example.

When Table 2 is seen, in the hardened | cured material (comparative examples 1 and 2) formed with the composition A or the composition B which does not contain a crosslinking agent, transparency after a heating is favorable, but solvent resistance becomes inadequate. It has been found. Moreover, it turned out that the embedding property is bad in the hardened | cured material (comparative example 3) formed with the composition K using the polymer which does not contain the structure of General formula (1). Further, in the polymer of the general formula (2), a cured product formed by the compositions D to J and L containing a polymer in which l: m is in the range of 70:30 to 100: 0 (Example 1) In (8 ) to (8 ), it was found that a coating film excellent in transparency after heating and solvent resistance was obtained without any decrease in embedding property and refractive index.

  The photoelectric conversion element of the present invention can be applied to various applications such as a digital camera, a video camera, a camera-equipped mobile phone, a scanner, a digital copying machine, and a facsimile. Moreover, according to the manufacturing method of the photoelectric conversion element of this invention, the photoelectric conversion element which has the optical waveguide part excellent in transparency and solvent tolerance can be manufactured easily.

DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 20 ... Photoelectric conversion part, 30, 30a ... Optical waveguide part, 40, 40a ... Interlayer insulation layer, 42 ... Hole, 50 ... On-chip lens, 100 ... Photoelectric conversion element

Claims (11)

A substrate,
A photoelectric conversion unit formed above the substrate;
An optical waveguide part formed above the photoelectric conversion part;
With
The optical waveguide portion contains a cured product of a composition containing sulfur and a polyimide having a refractive index at 633 nm of 1.60 or more, and a crosslinking agent,
The photoelectric conversion element in which the said hardened | cured material contains the structure represented by following General formula (2).

(In the general formula (2), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently R represents an integer of 0 to 4, R represents a tetravalent organic group, n represents an integer of 1 to 4, l and m represent an integer of 1 to 100,000 in total l + m, and l: m is 70:30 to 93: 7. ) In claim 1,
The photoelectric conversion element whose said R is a C4-C12 tetravalent aliphatic or alicyclic hydrocarbon. In claim 1 or claim 2,
The photoelectric conversion element in which the cross-linking agent is at least one selected from an alkyl etherified product of methylol melamine, an alkyl etherified product of a methylol melamine condensate, and a polyfunctional vinyl ether compound. In any one of Claims 1 to 3,
The optical waveguide portion has a columnar shape, and one end in a longitudinal direction of the columnar shape is optically connected to the photoelectric conversion portion. In claim 4,
In a cross section parallel to the longitudinal direction of the optical waveguide portion, the length in the longitudinal direction is not less than 0.5 times and not more than 10 times the maximum length in the direction perpendicular to the longitudinal direction. , Photoelectric conversion element. Forming a photoelectric conversion part above the substrate;
Forming an interlayer insulating layer so as to cover the photoelectric conversion part;
Forming a hole penetrating the upper surface of the photoelectric conversion unit in the interlayer insulating layer;
Filling the hole with a polymer having a structure represented by the following general formula (2) and a composition containing a crosslinking agent;
Curing the composition;
The manufacturing method of the photoelectric conversion element containing this.

(In the general formula (2), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently R represents an integer of 0 to 4, R represents a tetravalent organic group, n represents an integer of 1 to 4, l and m represent an integer of 1 to 100,000 in total l + m, and l: m is 70:30 to 93: 7. ) In claim 6,
The manufacturing method of the photoelectric conversion element whose said R is a C4-C12 tetravalent aliphatic or alicyclic hydrocarbon. In claim 6 or claim 7,
When the total amount of the composition excluding the organic solvent in the composition is 100% by mass, the polymer containing the structure represented by the general formula (2) is 80% by mass to 99% by mass. The manufacturing method of the photoelectric conversion element by which a crosslinking agent contains 1 mass% or more and 20 mass% or less. Including a polymer having a structure represented by the following general formula (2), a crosslinking agent, and an organic solvent capable of uniformly dissolving them,
When the total amount of components excluding the organic solvent is 100% by mass, the polymer containing the structure represented by the general formula (2) is 80% by mass to 99% by mass, and the crosslinking agent is 1% by mass to 20% by mass. A composition for forming an optical waveguide, contained in an amount of not more than%.

(In General Formula (2), each R ¹ is independently an alkyl group having 1 to 3 carbon atoms or a cyano group,
Or, it shows two R ¹ is bonded to a divalent sulfur atom, a is independently an integer of 0 to 4, R is a tetravalent organic group, n represents an integer of 1 to 4 1 and m are total integers of 1 to 100,000, and l: m is 70:30 to 93: 7 . ) In claim 9,
The composition for forming an optical waveguide, wherein R is a tetravalent aliphatic or alicyclic hydrocarbon having 4 to 12 carbon atoms. Hardened | cured material of the composition containing the polymer containing the structure represented by following General formula (2), and a crosslinking agent.

(In the general formula (2), R ¹ each independently represents an alkyl group or a cyano group having 1 to 3 carbon atoms or, two of R ¹ represents a bond to a divalent sulfur atom, a is independently R represents an integer of 0 to 4, R represents a tetravalent organic group, n represents an integer of 1 to 4, l and m represent an integer of 1 to 100,000 in total l + m, and l: m is 70:30 to 93: 7. )

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