JP2925164B2 - Pattern making method - Google Patents

Description

The present invention relates to a method for producing a relief pattern of a photosensitive resin composition having a large refractive index difference.

[Prior art] Conventionally, a cross-linking reaction or a molecule disintegration reaction occurs in an exposed portion of a photosensitive resin, and the exposed portion becomes hardly soluble or easily solubilized. A relief pattern was prepared by a method of removing the photosensitive resin [Conventional method (1)].

In addition, a thin film is formed from a photosensitive resin composition obtained by doping a resin with a relatively volatile photoreactive substance having a higher refractive index than the resin, and then the thin film is irradiated with ultraviolet light, and the exposed portion is doped. A method of forming a pattern having a refractive index difference between an exposed portion and a non-exposed portion by rocking a substance and evaporating and removing a doping material in a non-exposed portion, that is, a so-called photo-rocking method (conventional method (2)). Known [Applied Physics Lett
ers), Vol. 26, No. 6, pp. 303-306 (1975)]. According to this method, it is reported that the film thickness of the exposed part is increased by about 10% as compared with the unexposed part.

Further, a thin film is formed from a photosensitive resin composition comprising an acrylic acid or methacrylic acid ester-based polymer or copolymer having a photoreactive double bond at the alcohol residue of the ester and an aromatic ketone or aromatic aldehyde. And
Then, the thin film is irradiated with ultraviolet rays, and then the unreacted aromatic ketone or aromatic aldehyde is removed to form a pattern having both a refractive index difference and an unevenness difference between an exposed portion and a non-exposed portion. [Conventional method (3)] is known (see JP-A-62-95525 and JP-A-62-95526).

[Problem to be Solved by the Invention] In the relief pattern of the photosensitive resin produced by the conventional method (1), the difference in the refractive index between the exposed portion and the non-exposed portion is very little or very small. In the pattern produced by the conventional method (2), the difference in the refractive index between the exposed portion and the non-exposed portion and the change in the thickness of the uneven portion are not sufficient.

According to the conventional method (3), the exposed portion of the photosensitive resin composition has a higher refractive index than the non-exposed portion, and a clear pattern having a large thickness can be produced. And heat resistance is not always sufficient.

The object of the present invention and the exposed portion of the photosensitive resin has a higher refractive index than the non-exposed portion, and has a surface relief structure having a large thickness, a highly stable pattern having excellent organic solvent resistance and heat resistance. It is to provide a manufacturing method.

[Means for Solving the Problems] According to the present invention, the above object is achieved by the following (a):
A pattern comprising the steps (b), (c) and (d), wherein the following step (e) is provided between the steps (c) and (d) as necessary. This is achieved by providing a fabrication method.

(A) Structural unit (I) represented by the following general formula [In the formula, X ¹ represents a hydrogen atom or an alkyl group, and Y ¹ represents a cycloalkenyl group or a general formula shown below. Represents a group represented by Here, Z ¹ represents a divalent hydrocarbon group, and R ¹ , R ² and R ³ each represent a hydrogen atom, an alkyl group or an alkenyl group. And a structural unit (II) represented by the following general formula: [Wherein, X ² represents a hydrogen atom or an alkyl group, Y ² represents a phenyl group, an alkoxycarbonyl group or a carbamoyl group, and the hydrogen atom in the structural unit (II) may be substituted by a fluorine atom. Good. A photosensitive resin composition comprising a polymer (A) having from 0 to 98 mol% and a compound (B) selected from the group consisting of an aromatic aldehyde and an aromatic ketone which may have a substituent. Step of forming a thin film.

(B) A step of partially irradiating the thin film with ultraviolet rays according to a desired pattern.

(C) a step of removing unreacted compound (B) from the thin film by heat treatment under reduced pressure or normal pressure.

(D) a step of heat-treating the thin film at a temperature higher than the heat treatment temperature of the step (c).

(E) A step of irradiating the entire surface of the thin film with ultraviolet rays.

The polymer (A) constituting the photosensitive resin composition used in the present invention preferably contains 5 to 100 mol% of the structural unit (I). The polymer (A) further comprises a structural unit (III) represented by the following general formula: [Wherein X ³ represents a hydrogen atom or an alkyl group, and Z ² represents 2
R ⁴ , R ⁵ and R ⁶ each represent a hydrogen atom or an alkyl group. May be contained in an amount of 1 to 98 mol%, preferably 5 to 98 mol%.

X ¹ in the above structural unit (I) and the structural unit (II
The alkyl group represented by X ³ in I) is preferably a lower alkyl group having 4 or less carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group. The alkyl groups represented by R ¹ , R ² and R ³ in the structural unit (I) and R ⁴ , R ⁵ and R ⁶ in the structural unit (III) may have a branched or arbitrary substituent, Methyl, ethyl, propyl, isopropyl, butyl, amyl, hexyl, heptyl,
A lower alkyl group having 8 or less carbon atoms, such as an octyl group, is preferred. The alkenyl group represented by each of R ¹ , R ² and R ³ is a 2-butenyl group, a 3-methyl-2-butenyl group,
A 3-pentenyl group and a 4-methyl-3-pentenyl group are preferred. Z ¹ in the structural unit (I) and the structural unit (II
Examples of the divalent hydrocarbon group Z ² represents respectively in I) preferably optionally branched alkylene group having 2 to 8 carbon atoms. Preferred examples of Y ¹ in the structural unit (I) include:
Allyl group; 2-butenyl group, 3-butenyl group, 2-methyl-2-propenyl group; 2-heptenyl group, 3-heptenyl group, 4-heptenyl group, 2-methyl-2-butenyl group,
3-methyl-2-butenyl group, 2-ethyl-2-propenyl group, 2-methyl-3-butenyl group, 1,2-dimethyl-2-propenyl group; 2-hexenyl group, 3-hexenyl group, 4- Hexenyl group, 5-hexenyl group, 1,1-dimethyl-2-butenyl group, 1,2-dimethyl-2-butenyl group, 1,3-dimethyl-2-butenyl group, 2,3-dimethyl-
2-butenyl group, 3-methyl-2-heptenyl group, 2-
Methyl-2-heptenyl group; 2-methyl-2-cyclohexenyl group, 3-methyl-2-cyclohexenyl group, geranyl group, isogeranyl group, neryl group, lavanjuyl group, 6-methylgeranyl group, 1-methylgeranyl group , 6
-Ethylgeranyl group, perillyl group, funaresol group, geranylgeranyl group, β-cyclogeranylgeranyl group and the like.

The group in the structural unit (III) [Hereinafter referred to as group Y ^3] as the 2,3-epoxypropyl group, 2,3-epoxy butyl group, 3,4-epoxy butyl group, 2,3-epoxy-2-methylpropyl group, 2- Methyl-2,3-epoxybutyl group, 3-methyl-2,3-epoxybutyl group, 2,3-epoxyheptyl group, 5,6-epoxyheptyl group, 3-methyl-2,3-epoxybutyl group, 4
-Methyl-2,3-epoxyheptyl group, 4-methyl-5,6
-An epoxyheptyl group and the like.

The polymer (A) is obtained by homopolymerization of acrylic acid or its ester which may be substituted at the α-position by an alkyl group or copolymerization with a comonomer forming the structural unit (II). alcohols having a polymer and groups Y ^1, or is reacted with an alcohol having a group Y ³ if necessary, or acrylic acid derivative to form a structural unit (I) homopolymerization or the acrylic acid derivative and the comonomer addition If necessary, it can be produced by copolymerization with an acrylic acid derivative forming the structural unit (III).

The acrylic acid derivative forming the structural unit (I) includes allyl methacrylate, allyl acrylate,
(Or 3) -butenyl methacrylate, 2 (or 3) -butenyl acrylate, 2-methyl-2-propenyl methacrylate, 2-methyl-2-propenyl acrylate, 2 (or 3 or 4) -heptenyl methacrylate, 2 (Or 3 or 4) -heptenyl acrylate, 2-methyl-2 (or 3) -butenyl methacrylate, 2-methyl-2 (or 3) -butenyl acrylate, 2-ethyl-2-propenyl methacrylate, 2- Ethyl-2-propenyl acrylate, 1,2-
Dimethyl-2-propenyl methacrylate, 1,2-dimethyl-2-propenyl acrylate, 2 (or 3 or 4 or 5) -hexenyl methacrylate, 2 (or 3 or 4 or 5) -hexenyl acrylate,
1 (or 1,2 or 1,3 or 2,3) -dimethyl-2-butenyl methacrylate, 1,1 (or 1,2 or 1,3 or 2,3) -dimethyl-2-butenyl acrylate, 2
(Or 3) -methyl-2-heptenyl methacrylate, 2 (or 3) -methyl-2-heptenyl acrylate or other acrylic acid derivative in which an alcohol residue is in a chain; 2 (or 3) -methyl- Acrylic acid derivatives in which alcohol residues such as 2-cyclohexenyl methacrylate, 2 (or 3) -methyl-2-cyclohexenyl acrylate are cyclic; geranyl methacrylate, geranyl acrylate, neryl methacrylate, neryl acrylate, isogeneryl methacrylate, Isogeranyl acrylate, lavanjuyl methacrylate, lavanjuyl acrylate, 6-methylgeranyl methacrylate, 6-methylgeranyl acrylate, 1
-Methylgeranyl methacrylate, 1-methylgeranyl acrylate, 6-ethylgeranyl methacrylate, 6
Esters of a chain or cyclic terpene alcohol having two non-conjugated double bonds such as ethylgeranyl acrylate, perillyl methacrylate, perillyl acrylate and acrylic acid or methacrylic acid; Geranylgeranyl methacrylate, geranylgeranyl acrylate, β
A non-conjugated double bond such as cyclogeranylgeranyl methacrylate, β-cyclogeranylgeranyl acrylate;
An ester of a linear or cyclic terpene-based alcohol having at least one acrylic acid or methacrylic acid is exemplified. Among these, allyl methacrylate, 2-methyl-2-propenyl methacrylate, 2-butenyl methacrylate, 2-methyl-2-butenyl methacrylate,
2-hexenyl methacrylate, 3-hexenyl methacrylate, and geranyl methacrylate are preferred from the viewpoint of easy availability of alcohol as a raw material and ease of ester synthesis.

The acrylic acid derivatives forming the structural unit (III) include 2,3-epoxypropyl methacrylate and 2,3-epoxypropyl methacrylate.
Epoxy propyl acrylate, 2,3-epoxybutyl methacrylate, 2,3-epoxybutyl acrylate,
3,4-epoxybutyl methacrylate, 3,4-epoxybutyl acrylate, 2-methyl-2,3-epoxypropyl methacrylate, 2-methyl-2,3-epoxypropyl acrylate, 2,3-epoxyheptyl methacrylate, 5, 6-epoxyheptyl methacrylate, 2,3-epoxyheptyl acrylate, 5,6-epoxyheptyl acrylate, 2 (or 3) -methyl-2,3-epoxybutyl methacrylate, 2 (or 3) -methyl-2,3
-Epoxybutyl acrylate, 4-methyl-2,3-epoxyheptyl methacrylate, 4-methyl-5,6-epoxyheptyl methacrylate, 4-methyl-2,3-epoxyheptyl acrylate, 4-methyl-5,6-epoxy Heptyl acrylate. Among these, 2,3-epoxypropyl methacrylate, 2,3-epoxybutyl methacrylate, and 3,4-epoxybutyl methacrylate are preferable from the viewpoint of ease of ester synthesis.

Examples of the comonomer forming the structural unit (II) include methacrylic acid; alkyl methacrylate such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, amyl methacrylate, and cyclohexyl methacrylate. Ester; acrylic acid; alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, amyl acrylate, cyclohexyl acrylate, methacrylamide, acrylamide Styrene, substituted styrene such as α-methylstyrene, and the like. A hydrogen atom in the structural unit (II) may be substituted by a fluorine atom.

The polymer (A) has a number average molecular weight in the range of 1,000 to 1,000,000 determined by gel permeation chromatography. The number average molecular weight of the polymer (A) is 100,
It is preferably in the range of 000 to 800,000.

As the compound (B), for example, benzaldehyde, benzophenone or a derivative thereof which may have a substituent may be mentioned. Specifically, the following general formulas (IV) and (V)
Alternatively, it is represented by the general formula (VI).

[Where X ⁴ , X ⁵ , X ⁶ , X ⁷ , X ⁸ , X ⁹ , X ¹⁰ , X ¹¹ and X ¹²
Represents a hydrogen atom, an alkyl group or an alkoxy group having 7 or less carbon atoms, or a halogen atom, and X ¹³ ,
X ¹⁴ , X ¹⁵ , X ¹⁶ , X ¹⁷ and X ¹⁸ each represent a hydrogen atom or a halogen atom. n is 0, 1 or 2. Preferred compounds (B) include benzophenone; 3 (or 4) -methylbenzophenone, 3 (or 4) -methoxybenzophenone, 3,3 ′ (or 4,4 ′)-dimethylbenzophenone, Substituted benzophenones such as 3,3 '(or 4,4')-dimethoxybenzophenone, 2,3 (or 2,4) -chlorobenzophenone, 3,4,5-trimethoxybenzophenone, 3-benzoyl Benzophenone; 3 (or 4) -methylbenzoyl-3 ′ (or 4 ′)-methylbenzophenone, 3 (or 4) -methoxybenzoyl-3 ′ (or 4 ′)-methoxybenzophenone,
Meta-substituted benzophenones such as 3,3'-dibenzoylbenzophenone, 1,3,5-tribenzoylbenzophenone, benzaldehyde; 3 (or 4) -methylbenzaldehyde, 3 (or 4) -methoxybenzaldehyde, Examples include substituted benzaldehydes such as 3,4-dimethylbenzaldehyde and 3,4-dimethoxybenzaldehyde. Of these, benzaldehyde, benzophenone, 3-benzoylbenzophenone, 3,3'-dibenzoylbenzophenone and 1,3,5-tribenzoylbenzene are preferred because of their ease of synthesis, and particularly 3-
Benzoylbenzophenone and 1,3,5-tribenzoylbenzene have good photoreactivity and can increase the unevenness and refractive index difference between exposed and unexposed areas. Is particularly preferred because of its high solvent resistance and heat resistance.

The composition ratio of the polymer (A) and the compound (B) is 10: 1 to 1:
A range of 10 (weight ratio) is preferred. The ratio of the structural unit (I) and the compound (B) in the polymer (A) is 10: 1 to 1:20.
(Molar ratio), preferably 5: 1 to 1:10 (molar ratio).

In the step (a), the polymer (A) and the compound (B) are dissolved in a solvent that dissolves them, and a thin film is formed by a casting method, a bar coating method, a spin coating method, or the like. If necessary, the solvent is removed from the thin film by subjecting the thin film to a vacuum treatment or a heat treatment. The method of forming the thin film is selected according to the desired thickness or form of the thin film. Generally, when the thickness is large, the casting method,
If smaller, a bar coating method or a spin coating method is employed.

In the step (b) following the step (a), the thin film is partially irradiated with ultraviolet rays having a wavelength of 200 to 450 nm according to a desired pattern. High pressure mercury lamp as a light source, N ₂ gas lasers, the He-Cd
A laser or the like is used. As a method of forming a desired pattern, a mask exposure method using a photomask, a two-beam interference exposure method, a laser beam direct writing method, or the like is employed.

The removal of the unreacted compound (B) in the step (c) following the step (b) is usually carried out by heat treatment under reduced pressure or normal pressure. The temperature of the heat treatment is preferably in the range of 50 to 100 ° C. Thus, a pattern having a desired difference in refractive index and a difference in unevenness is obtained.

When the step (d) of applying a heat treatment at a temperature higher than the heat treatment temperature of the step (c) to the thin film of the photosensitive resin composition on which the desired pattern is formed is provided, the organic solvent resistance and heat resistance of the pattern are improved. I do. (D) 105 to 2 heat treatments
Performing at a temperature in the range of 30 ° C. for 15 minutes to 40 hours gives suitable results. More preferably, heat treatment is performed at a temperature in the range of 150 to 200 ° C. for 1 to 5 hours, or at a temperature in the range of 110 to 140 ° C. for 10 to 25 hours.

If the step (e) of irradiating the entire surface of the thin film with ultraviolet rays is provided between the steps (c) and (d), the organic solvent resistance and the heat resistance are further improved. 10 for UV intensity
4040 mW / cm ² , the wavelength is preferably 200 to 450 nm, and the ultraviolet irradiation time is preferably 30 seconds to 5 minutes.

According to the present invention, for example, patterns such as an optical waveguide, a diffraction grating, a grating lens, a Fresnel lens, and a hologram lens can be manufactured. These patterns are extremely excellent in optical transparency, organic solvent resistance and heat resistance.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples.

Example 1 A test tube was charged with 26 g of 2-butenyl methacrylate, 56 g of methyl methacrylate, 90 mg of azobisisobutyronitrile and 300 g of dioxane with N ₂ substitution, sealed, and sealed with
Polymerization was performed by heating in a water bath at 60 ° C. for 24 hours. Thereafter, the reaction solution was poured into 1 of methanol, and the produced polymer (A) was precipitated and dried to obtain 50 g. When the composition ratio of this polymer (A) was measured by NMR, it was confirmed that the copolymer was 2-butenyl methacrylate: methyl methacrylate = 1: 3 (molar ratio). The molecular weight of this polymer was 220,000 as measured by gel permeation chromatography. 1 part of the above polymer (A) and 3-benzoylbenzophenone 0.
Dissolve the photosensitive resin composition consisting of 8 parts in toluene,
A thin film (thickness 1.5) is formed on a glass substrate by spin coating.
μm). This thin film was heat-treated at 60 ° C. for 30 minutes, and then irradiated with ultraviolet rays of 350 nm and 25 mW / cm ² for 5 minutes through a photomask having a line and space with a period of 20 μm. After UV irradiation, remove the photomask and heat treat it in a vacuum dryer at 98 ° C and 0.2 mmHg for 17 hours to remove the non-exposed part of compound (B) to obtain a diffraction grating pattern having a difference in refractive index and unevenness. Was prepared. Further, the pattern of the diffraction grating was subjected to a heat treatment in the step (d) at 120 ° C. (normal pressure) for 24 hours. The diffraction efficiency of this diffraction grating was 12% for light of 780 nm.

(D) The diffraction grating subjected to the heat treatment in the step was left in a saturated vapor of methyl methacrylate at 70 ° C. for 100 hours, but the diffraction efficiency did not change. From this, it was determined that the shape and the refractive index of the diffraction grating did not change. The diffraction grating was heated at 180 ° C. (normal pressure) for 2 hours, but the diffraction efficiency did not change.

Example 2 Using the photosensitive resin composition having the same composition as in Example 1, a diffraction grating pattern was produced in the same manner as in Example 1.
This diffraction grating pattern was subjected to a heat treatment in the step (d) at 180 ° C. (normal pressure) for 2 hours.

An organic solvent resistance test and a heat resistance test were conducted in the same manner as in Example 1 using the heat-treated diffraction grating, but the diffraction efficiency of the diffraction grating did not change.

Examples 3 to 8 In the same manner as in Example 1, photosensitive resin compositions comprising the polymer (A) and the compound (B) shown in Table 1 were prepared, and patterns of diffraction gratings were prepared. Then 30mW
/ cm ² UV light for 2 minutes, then at 120 ℃ (normal pressure)
The heat treatment of the process (d) for 4 hours was performed. When the organic solvent resistance and the heat resistance were tested in the same manner as in Example 1 using the diffraction gratings produced in each of the examples, none of the diffraction efficiencies was changed.

Also, the diffraction grating in which the heat treatment conditions in the step (d) were changed to 180 ° C. (normal pressure) for 2 hours also showed high organic solvent resistance and heat resistance.

Example 9 A test tube was charged with 26 g of 2-butenyl methacrylate, 26 g of 2,3-epoxypropyl methacrylate, 38 g of methyl methacrylate, 90 mg of azobisisobutyronitrile, and 300 g of dioxane after substituting with N ₂ , and the tube was sealed. Polymerization was performed by heating for 24 hours in a water bath at 60C to 60C. When the composition ratio of this polymer was measured by NMR in the same manner as in Example 1,
It was confirmed that the copolymer was 2-butenyl methacrylate: 2,3-epoxypropyl methacrylate: methyl methacrylate = 1: 1: 2 (molar ratio). The molecular weight was measured by gel permeation chromatography, and the number average molecular weight was 220,000. A photosensitive resin composition comprising 1 part of the above polymer (A) and 0.8 part of 3-benzoylbenzophenone was dissolved in toluene, and a thin film (thickness: 1.5 μm) was formed by spin coating as in Example 1. Was formed. This thin film was heat-treated at 60 ° C. for 30 minutes, and then irradiated with ultraviolet rays of 25 mW / cm ² through the photomask for 5 minutes. After UV irradiation, remove the photomask and put it in a vacuum dryer at 98 ° C.
Heat treatment was performed for 17 hours under the condition of 0.2 mmHg to form a diffraction grating pattern. Further, the diffraction grating is heated at 140 ° C (normal pressure) for 20
The heat treatment of the step (d) for a long time was performed. (D) When the organic solvent resistance and the heat resistance were tested under the same conditions as in Example 1 using the heat-treated diffraction grating in the step, the diffraction efficiency of the diffraction grating did not change. Also, the diffraction grating in which the heat treatment conditions in the step (d) were changed to 180 ° C. (normal pressure) for 2 hours also showed high organic solvent resistance and heat resistance.

Examples 10 to 17 In the same manner as in Example 2, photosensitive resin compositions comprising the polymer (A) and the compound (B) shown in Table 1 were prepared, and a diffraction grating pattern was prepared. Then 30mW
/ cm ² UV light for 2 minutes, then at 120 ℃ (normal pressure)
The heat treatment of the process (d) for 4 hours was performed. When the organic solvent resistance and the heat resistance were tested under the same conditions as in Example 1 by using the diffraction gratings produced in each of the examples, none of the diffraction efficiencies was changed.

In addition, the heat treatment conditions in the step (d) are 180 ° C. (normal pressure),
Even in the diffraction grating pattern changed in time, the organic solvent resistance and the heat resistance were high.

Example 18 In a test tube, geranyl methacrylate 39 g, 2,3-epoxypropyl methacrylate 26 g, methyl methacrylate 38
g, azobisisobutyronitrile 90 mg and dioxane 3
Were charged with N _{2-substituted} 200 g, it was heated to the polymerization for 24 hours in water bath and sealed by 55 to 60 ° C.. Thereafter, the reaction solution was poured into 1 of methanol, and the produced polymer (A) was precipitated and dried to obtain 45 g. When the composition ratio of the polymer (A) was measured by NMR, geranyl methacrylate: 2,
It was confirmed that the copolymer was 3-epoxypropyl methacrylate: methyl methacrylate = 1: 1: 2 (molar ratio). The molecular weight of this polymer was measured by gel permeation chromatography,
It was 190,000. A photosensitive resin composition comprising 1 part of the polymer (A) and 0.8 part of 1,3,5-tribenzoylbenzene is dissolved in toluene, and a thin film (thickness: 1.5) is formed on a glass substrate by spin coating. μm). 6
After a heat treatment at 0 ° C. for 30 minutes, an ultraviolet ray of 25 mW / cm ² was irradiated for 5 minutes through a photomask having a line and space with a period of 20 μm. After irradiation, remove the photomask and heat treat it in a vacuum dryer at 98 ° C and 0.2 mmHg for 17 hours.
The unreacted compound (B) was removed to form a diffraction grating pattern having a difference in refractive index and a difference in unevenness. This diffraction grating was subjected to a heat treatment in the step (d) at 180 ° C. (normal pressure) for 2 hours.

Example 1 using the diffraction grating subjected to the heat treatment in the step (d)
When the organic solvent resistance and the heat resistance were tested under the same conditions as in the above, the diffraction efficiency of the diffraction grating did not change. Also,
(D) When a similar test was conducted for the resistance to organic solvents and heat resistance using a diffraction grating in which the heat treatment conditions in the step were changed to 120 ° C. (normal pressure) and 24 hours, the diffraction efficiency of the diffraction grating did not change. Was.

Examples 19 to 26, Comparative Examples A to C Using a photosensitive resin composition having the same composition as in Example 1 or 2, a diffraction grating pattern was produced in the same manner. Then, under the conditions shown in Table 3, the heat treatment in the step (d), the heat treatment in the step (d), and the ultraviolet irradiation in the step (e) were performed. Thereafter, the diffraction grating was left in methyl methacrylate saturated vapor at various temperatures for 100 hours. The diffraction efficiency did not change in any of the examples. The diffraction grating of the above example was heated at 180 ° C. (normal pressure) for 2 hours, but the diffraction efficiency did not change.

Further, as Comparative Examples A to C of the pattern production method of the present invention, a pattern of a diffraction grating was produced by the same method using a photosensitive resin composition having the same composition as in Example 1 or Example 2, and Table 3 shows the case where the heat treatment in the process was not performed. When this diffraction grating was allowed to stand in methyl methacrylate saturated vapor at 50 ° C. or 70 ° C., the grating pattern swelled and deformed after 10 hours, and the diffraction efficiency changed.
Further, when heated at 180 ° C. (normal pressure) for 2 hours, the diffraction efficiency changed.

Parts in Tables 1 to 3 indicate parts by weight.

[Effects of the Invention] According to the present invention, a pattern in which an exposed portion of a photosensitive resin has a higher refractive index than a non-exposed portion, has a surface relief structure having a large thickness, and is excellent in organic solvent resistance and heat resistance. Can be produced.

Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI G03F 7/40 501 G02B 6/12 M (56) References JP-A-60-166946 (JP, A) JP-A-62-95525 (JP, A) JP-A-62-95526 (JP, A) JP-A-50-901 (JP, A) JP-A-56-120718 (JP, A) JP-A-63-17593 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) G03F 7/038 G03F 7/028 G03F 7/40 G03F 7/004

Claims (1)

(57) [Claims] 1. A structural unit (I) represented by the following general formula: [In the formula, X ¹ represents a hydrogen atom or an alkyl group, and Y ¹ represents a cycloalkenyl group or a general formula shown below. Represents a group represented by Here, Z ¹ represents a divalent hydrocarbon group, and R ¹ , R ² and R ³ each represent a hydrogen atom, an alkyl group or an alkenyl group. And a structural unit (II) represented by the following general formula: [Wherein, X ² represents a hydrogen atom or an alkyl group, Y ² represents a phenyl group, an alkoxycarbonyl group or a carbamoyl group, and the hydrogen atom in the structural unit (II) may be substituted by a fluorine atom. Good. A photosensitive resin composition comprising a polymer (A) having from 0 to 98 mol% and a compound (B) selected from the group consisting of an aromatic aldehyde and an aromatic ketone which may have a substituent. (B) partially irradiating the thin film with ultraviolet rays according to a desired pattern; (c) removing unreacted compound (B) from the thin film by heat treatment under reduced pressure or normal pressure And (d) heat-treating the thin film at a temperature higher than the heat treatment temperature of the step (c). If necessary, the step (c) may be performed between the steps (c) and (d). A step of irradiating the entire surface of the thin film with ultraviolet rays.