JP2931436B2 - Pattern making method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related 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 dissolved. A relief pattern was prepared by a method of removing the photosensitive resin [Conventional method (1)].

Further, 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. A method of forming a pattern having a refractive index difference between an exposed portion and a non-exposed portion by locking the doping material in the portion and evaporating and removing the doping material in the unexposed portion, a so-called photo-locking method [conventional method (2)] ] [Applied Physics Letters (Appli
Physics Letters), Vol. 26,
No. 6, pages 303-306 (1975)]. According to this method, it is reported that the film thickness is increased by about 10% in the exposed part as compared with the non-exposed part.

Further, a photosensitive resin composition comprising an acrylic acid or methacrylic acid ester-based polymer or copolymer having a photoreactive double bond at an alcohol residue of an ester and an aromatic ketone or aromatic aldehyde. Forming a thin film, then irradiating the thin film with ultraviolet light, and then heating or placing the thin film under reduced pressure to remove the unreacted aromatic ketone or aromatic aldehyde, thereby exposing the exposed portion and the unexposed portion. (Conventional method (3)) for producing a pattern having both a refractive index difference and a concavo-convex difference between the same (see JP-A-62-95525 and JP-A-6-95525).
2-95526).

[0005]

In the relief pattern of the photosensitive resin prepared by the conventional method (1), the difference in the refractive index between the exposed portion and the non-exposed portion is 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), a clear pattern having a higher refractive index in the exposed portion of the photosensitive resin composition than the unexposed portion and a large thickness can be formed. By heating or placing the film under reduced pressure,
When the unreacted aromatic ketone or aromatic aldehyde present in the non-exposed area is selectively removed, a large difference in refractive index and unevenness between the exposed area and the non-exposed area is obtained.
However, at that time, unreacted aromatic ketones or aromatic aldehydes present in the exposed portions are also removed. In order to reduce the amount of unreacted aromatic ketone or aromatic aldehyde present in the exposed area, it is necessary to increase the energy of the ultraviolet light applied to the thin film or to lengthen the irradiation time, which lowers the productivity.

An object of the present invention is to provide a pattern having a surface relief structure in which the exposed portion of a thin film made of a photosensitive resin composition has a higher refractive index and a larger thickness than the unexposed portion, and has excellent heat resistance. Is to provide a method for producing a high productivity with a short exposure time.

[0008]

According to the present invention, the above object has been achieved by the following steps (a), (b), (c) and (d). Achieved by providing a law.

(A) The following general formula (I)

Embedded image [Wherein, X ¹ represents a hydrogen atom or an alkyl group, and Y ¹ represents a cycloalkenyl group or the following general formula (III)

Embedded image 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. (Hereinafter referred to as the structural unit (I)) in the range of 2 to 100
Mol%, and the following general formula (II)

Embedded image [In the formula, 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 general formula (II) may be substituted by a fluorine atom. (Hereinafter referred to as a structural unit (II)) from 0 to 98
Step of forming a thin film of a photosensitive resin composition comprising a polymer (A) having a mole% and a compound (B) selected from the group consisting of an aromatic aldehyde and an aromatic ketone which may have a substituent. . (B) A step of partially irradiating the thin film with ultraviolet rays according to a desired pattern. (C) a step of dissolving and removing the unreacted compound (B) from the thin film using a solvent in which the polymer (A) is not dissolved. (D) 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 alkyl group represented by X ¹ in the structural unit (I) and X ² in the structural unit (II) has a carbon number of 4 such as a methyl group, an ethyl group, a propyl group, an isopropyl group and a butyl group. The following lower alkyl groups are preferred. The alkyl group represented by R ¹ , R ² and R ³ in the structural unit (I) may have a branched chain or an arbitrary substituent, and may be a methyl group, an ethyl group, a propyl group, an isopropyl group or a butyl group. And a lower alkyl group having 8 or less carbon atoms, such as amyl group, hexyl group, heptyl group and octyl group. The above R ¹ , R ² and R ³
Is preferably a 2-butenyl group, a 3-methyl-2-butenyl group, a 3-pentenyl group, or a 4-methyl-3-pentenyl group. As the divalent hydrocarbon group represented by Z ¹ in the structural unit (I), an alkylene group having 2 to 8 carbon atoms which may have a branched chain is preferable. Preferred examples of Y ¹ in the structural unit (I) include an allyl group;
-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-
A cyclohexenyl group, a 3-methyl-2-cyclohexenyl group, a geranyl group, an isogeranyl group, a neryl group, a lavanjuyl group, a 6-methylgeranyl group, a 1-methylgeranyl group, a 6-ethylgeranyl group, a perillyl group, a phnesol group, A geranylgeranyl group, a β-cyclogeranylgeranyl group and the like can be mentioned.

Preferred examples of the alkoxycarbonyl group represented by Y ² in the structural unit (II) include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, a butoxycarbonyl group, a pentanoxycarbonyl group, a hexanoxycarbonyl group, Heptanoxycarbonyl group, cyclohexanoxycarbonyl group and the like can be mentioned.

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). By reacting the polymer with an alcohol having a group Y ¹ , or by homopolymerization of an acrylic acid derivative forming the structural unit (I) or copolymerization of the acrylic acid derivative and the acrylic acid derivative forming the comonomer Can be manufactured.

The acrylic acid derivative forming the structural unit (I) includes allyl methacrylate, allyl acrylate, 2 (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, 1,1 (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
-An acrylic acid derivative in which an alcohol residue such as heptenyl methacrylate, 2 (or 3) -methyl-2-heptenyl acrylate is chained; 2 (or 3)-
Acrylic acid derivatives in which alcohol residues such as methyl-2-cyclohexenyl methacrylate, 2 (or 3) -methyl-2-cyclohexenyl acrylate are cyclic; geranyl methacrylate, geranyl acrylate, neryl methacrylate, neryl acrylate, isogeneryl Methacrylate, isogeranyl acrylate,
Lavandiuryl methacrylate, Lavandiuryl acrylate, 6-methylgeranyl methacrylate, 6-methylgeranyl acrylate, 1-methylgeranyl methacrylate, 1-methylgeranyl acrylate, 6-ethylgeranyl methacrylate, 6-ethylgeranyl acrylate, perillyl methacrylate, Esters of chain or cyclic terpene alcohols having two non-conjugated double bonds such as perillyl acrylate with acrylic acid or methacrylic acid; fumaresol methacrylate, fumaresol acrylate, geranylgeranyl methacrylate, geranylgeranyl acrylate, β-cyclo A chain or cyclic terpene-based alcohol having three or more non-conjugated double bonds such as geranylgeranyl methacrylate, β-cyclogeranylgeranyl acrylate, etc. And esters of acrylic acid and methacrylic acid. 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.

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

The polymer (A) preferably has a polystyrene-equivalent number average molecular weight in the range of 1,000 to 1,000,000 as determined by gel permeation chromatography. The polymer (A) has a number average molecular weight of 100,
Those in the range of 000 to 800,000 are more preferred.

The compound (B) includes, for example, benzaldehyde, benzophenone or a derivative thereof which may have a substituent. Specifically, the following general formula (IV), general formula (V) or general formula (VI) ).

Embedded image

Embedded image

Embedded image [In the formula, X ³ , X ⁴ , X ⁵ , X ⁶ , X ⁷ , X ⁸ , X ⁹ , X ¹⁰ and X ¹¹ are each a hydrogen atom, an alkyl group having 7 or less carbon atoms or an alkoxy group, or a halogen atom. Represents an atom,
X ¹² , X ¹³ , X ¹⁴ , X ¹⁵ , X ¹⁶ and X ¹⁷ each represent a hydrogen atom or a halogen atom. n is 0, 1 or 2
It is. ]

Preferred compounds (B) are benzophenone; 3 (or 4) -methylbenzophenone, 3 (or 4) -methoxybenzophenone, 3,3 '(or 4,4')-dimethylbenzophenone, 3,3 '( Or substituted benzophenones such as 4,4 ′)-dimethoxybenzophenone, 2,3 (or 2,4) -chlorobenzophenone, 3,4,5-trimethoxybenzophenone,
3-benzoylbenzophenone; 3 (or 4) -methylbenzoyl-3 ′ (or 4 ′)-methylbenzophenone, 3 (or 4) -methoxybenzoyl-3 ′ (or 4 ′)-methoxybenzophenone, 3,3′- Meta-substituted benzophenones such as dibenzoylbenzophenone and 1,3,5-tribenzoylbenzene, benzaldehyde; 3 (or 4) -methylbenzaldehyde,
3 (or 4) -methoxybenzaldehyde, 3,4-
Examples include substituted benzaldehydes such as 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 3-benzoylbenzophenone and 1,3,3 5-Tribenzoylbenzene has good photoreactivity, can increase the difference in unevenness and refractive index between exposed and unexposed portions, and has high solvent resistance and high heat resistance in the produced pattern. It is particularly preferred in that respect.

The composition ratio of the polymer (A) and the compound (B) is preferably in the range of 10: 1 to 1:10 (weight ratio),
The range of 2: 1 to 1: 2 (weight ratio) is more preferable. The ratio of the structural unit (I) and the compound (B) in the polymer (A) is preferably in the range of 10: 1 to 1:20 (molar ratio),
The range of 5: 1 to 1:10 (molar ratio) is more preferable.

In the above step (a), the polymer (A) and the compound (B) are dissolved in a solvent that dissolves them, and the resulting solution is used to form a thin film by a casting method, a bar coating method, a spin coating method or the like. To form If necessary, the solvent is removed from the thin film by subjecting the thin film to a reduced pressure 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. The thickness of the thin film is 0.1-2
It is preferably in the range of 0 μm. Generally, when the thickness is large, a casting method is used, and when the thickness is small, a bar coating method or a spin coating method is used.

In the step (b) following the step (a), the wavelength of the thin film is partially set to 200 to 450 in accordance with a desired pattern.
Irradiate ultraviolet light of nm. This causes a photoreaction between the structural unit (I) and the compound (B). As a light source, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon-mercury lamp, a metal halide lamp, a N ₂ gas laser, a He—Cd 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, an ultraviolet beam direct writing method, or the like is employed. Here, the exposure energy is determined according to the type and composition of the polymer (A) and the compound (B) constituting the photosensitive resin composition, the development conditions in the step (c), and the like.

In the step (c) following the step (b),
Using a solvent that does not dissolve the polymer (A), the unreacted compound (B) in the thin film is dissolved and removed. Since the solvent has the property of dissolving the unreacted compound (B) without dissolving the polymer (A) in the photosensitive resin composition, the surface of the photosensitive resin composition becomes rough and whitened. Does not occur,
Only the unreacted compound (B) is dissolved and removed.

As the above-mentioned solvent, a fluorine-containing compound is preferable because it has a low surface tension, hardly corrodes the polymer (A), and dissolves low-molecular substances well. Examples of the fluorine-containing compound include chlorotrifluoromethane, 1,1,2-trichloro-1,2,2-trifluoroethane, 1,1,
2,2-tetrachloro-1,2-difluoroethane,
1,1-dichloro-2,2,2-trifluoroethane,
1,2-dichloro-1,1-difluoroethane, 1,1
-Dichloro-1-fluoroethane, 1,1,2-trichloro-1,2-difluoroethane, 2,2,3,3,3
-Pentafluoroethanol and the like are preferable in terms of solubility, availability, and the like. The fluorine-containing compound may be mixed with another compound such as a hydrocarbon compound or alcohol. When mixing the fluorine-containing compound with another compound, it is preferable that the fluorine-containing compound contains 5% or more (weight ratio) of the fluorine compound. Further, as the above-mentioned solvent, an alcohol having 5 or less carbon atoms is preferable because it hardly corrodes the polymer (A) and well dissolves a high-polarity low molecular weight substance. Examples of the alcohol having 5 or less carbon atoms include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, 2-pentanol, 3-pentanol, and 2-methyl. -1-butanol, 2-methyl-2-butanol, 3-
Methyl-1-butanol, 3-methyl-2-butanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2,3-propanetriol, 1,2-butanediol , 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, and the like are preferable in terms of solubility, availability, and the like. . The alcohol having 5 or less carbon atoms is preferably used in the form of an aqueous solution in order to make the polymer (A) less susceptible to attack. When alcohol is used in the form of an aqueous solution, it is preferable to contain the alcohol in an amount of 5% or more (weight ratio). A surfactant may be added to the alcohol to reduce the surface tension of the solvent so that the photosensitive resin surface is uniformly wetted.

In the step (d) following the step (c), it is preferable to irradiate the entire surface of the thin film of the photosensitive resin composition with ultraviolet rays having a wavelength of 200 to 450 nm. (C) The unreacted compound (B) remains in the exposed portion of the photosensitive resin composition thin film treated in the step, and the unreacted compound (B) is dissolved and removed between the unexposed portion and the unexposed portion. , A concentration gradient of the compound (B) occurs. By performing the step (d), the unreacted compound (B) remaining in the thin film undergoes a photoreaction with the structural unit (I), and the heat resistance of the pattern is improved without sagging the shape of the pattern. As the light source used in the step (d), those exemplified in the step (b) can be used.

After the step (d), a step (e) of subjecting the thin film of the photosensitive resin composition on which the desired pattern is formed to a heat treatment at a temperature in the range of 100 to 230 ° C. for 15 minutes to 40 hours is provided. In addition, the heat resistance of the formed pattern can be further improved.

According to the present invention, patterns such as an optical waveguide, a diffraction grating, a grating lens, a hologram lens, and a microlens array can be produced. The obtained pattern is excellent in transparency, organic solvent resistance and heat resistance.

[0027]

In the pattern forming method of the present invention, the unreacted compound (B) existing in the unexposed area is selectively dissolved and removed without dissolving the unreacted compound (B) existing in the exposed area. It is possible to obtain a pattern having a large difference between the refractive index and the unevenness between the exposed portion and the non-exposed portion even when the exposure time in the step (b) is short.

[0028]

The present invention will be described below in detail with reference to examples.

Example 1 A test tube was filled with 26 g of 2-butenyl methacrylate, 56 g of methyl methacrylate, and 90 g of azobisisobutyronitrile.
mg and 300 g of dioxane were charged with N ₂ substitution,
The tube was sealed and heated in a water bath at 55 to 60 ° C. for 24 hours to carry out a polymerization reaction. The reaction solution obtained was treated with methanol 1
The product was precipitated and dried to obtain 50 g of a polymer (A). This polymer (A) is NMR
As a result, it was confirmed that the copolymer was a copolymer having a molar ratio of 2-butenyl methacrylate to methyl methacrylate of 1: 3. The molecular weight of the polymer (A) was 220,000 in terms of polystyrene equivalent number average molecular weight determined by gel permeation chromatography. A photosensitive resin composition comprising 10 parts of the polymer (A) and 8 parts of 3-benzoylbenzophenone is dissolved in toluene, and a thin film (thickness: 1) is formed on a glass substrate by spin coating using the obtained solution. .5 .mu.m) [Step (a)]. After heat treating this thin film at 60 ° C. for 30 minutes, the obtained thin film is passed through a photomask having a line and space cycle of 20 μm to form a 350 nm, 25 m
Ultraviolet light of W / cm ² was irradiated for 30 seconds [(b) step]. After the ultraviolet irradiation, the photomask is removed, and the glass substrate is immersed in 1,1,2-trichloro-1,2,2-trifluoroethane at 25 ° C. for 10 minutes to remove the unreacted compound (B) in the unexposed portion. Thus, a diffraction grating pattern having a refractive index difference and a concavo-convex difference was prepared [Step (c)]. continue,
The entire surface of the thin film was irradiated with ultraviolet rays of 30 mW / cm ² for 10 minutes [Step (d)].

The depth of the diffraction grating thus obtained was found to be 0.3 μm by a stylus type surface shape measuring device (Taristep). No whitening or roughness occurred on the diffraction grating surface. The diffraction efficiency of this diffraction grating was 12% with respect to light having a wavelength of 780 nm. A heat resistance test was performed by heating the diffraction grating at 150 ° C. (normal pressure) for 2 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.

Example 2 Using a photosensitive resin composition having the same composition as in Example 1, the pattern of a diffraction grating produced in the same manner as in Example 1 was changed to 13
The heat treatment of the step (e) was performed at 0 ° C. (normal pressure) for 5 hours.

No whitening or roughening occurred on the surface of the diffraction grating subjected to the heat treatment. The diffraction efficiency of this diffraction grating was 12% with respect to light having a wavelength of 780 nm.
A heat resistance test was performed by heating the diffraction grating at 160 ° C. (normal pressure) for 2 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.

Examples 3 to 18 In the same manner as in Example 1, a photosensitive resin composition comprising the polymer (A) and the compound (B) shown in Tables 1 and 2 was prepared, and the pattern of the diffraction grating was changed. Produced.

When a heat resistance test was carried out 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, no whitening, roughness, etc. occurred on the surface of the diffraction grating.

In the same manner as in Example 1 except that the diffraction grating prepared in each of the examples was further subjected to a heat treatment in the step (e) of 130 ° C. (normal pressure) for 5 hours, heat resistance was obtained in the same manner as in Example 1. The tests did not change any of the diffraction efficiencies. In Tables 1 and 2, parts indicate parts by weight.

[Table 1]

[Table 2]

Example 19 Using a photosensitive resin composition having the same composition as in Example 1, a thin film (thickness: 1.5) was formed on a glass substrate in the same manner as in Example 1.
μm) was formed [Step (a)]. After heat-treating this thin film at 60 ° C. for 30 minutes, 25 mW / cm ^{2 is} passed through a photomask having a line and space of 20 μm cycle.
For 30 seconds [(b) step]. After the ultraviolet irradiation, the photomask was removed and the glass substrate was heated at 25 ° C. with a weight ratio of ethanol to water to surfactant of 1: 1 to 0.001.
5 minutes to remove the unreacted compound (B) in the non-exposed area, thereby producing a diffraction grating pattern having a refractive index difference and a concave-convex difference [(c) step]. Subsequently, the entire surface of the thin film was irradiated with ultraviolet rays of 30 mW / cm ² for 10 minutes [(d) step].

The diffraction efficiency of the thus obtained diffraction grating was 13% for light having a wavelength of 780 nm. No whitening or roughness occurred on the surface of the diffraction grating. When the diffraction grating was heated at 150 ° C. (normal pressure) for 2 hours, 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.

Examples 20 to 27 Using a photosensitive resin composition having the same composition as in Example 1 or 9, irradiating ultraviolet rays through a photomask in the same manner as in Example 1 ((b) step). Under the conditions shown, the unreacted compound (B) was dissolved and removed [Step (c)]. Subsequently, in the same manner as in Example 2, the entire surface of the thin film was irradiated with ultraviolet rays (step (d)), and then the heat treatment of step (e) was performed to form a diffraction grating pattern. The refractive index difference and the unevenness difference between the exposed part and the non-exposed part in the diffraction gratings manufactured in the respective examples are large. As shown in Table 3, all the diffraction gratings have a wavelength of 780 nm and 5% or more as shown in Table 3. Diffraction efficiency was obtained.

The diffraction grating fabricated in each of the examples
A heat resistance test was performed by heating at 0 ° C. (normal pressure) for 2 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.
Also, no whitening, roughness, etc. occurred on the surface of the diffraction grating. In Table 3, parts are parts by weight.

[Table 3]

Comparative Examples A to I As comparative examples A to I of the pattern forming method of the present invention, a diffraction grating was prepared under the conditions shown in Table 3 using a photosensitive resin composition having the same composition as in Example 1 or Example 9. Produced.

In Comparative Examples A, B and G, the solvent for dissolving and removing the unreacted compound (B) in the unexposed area was
A solvent that also dissolves the polymer (A) was used. As a result, the diffraction grating surface was whitened, and a clear pattern was not obtained.

In Comparative Examples C and H, the step (d) was not performed after the step (c). The diffraction gratings obtained in these comparative examples were subjected to a heat resistance test by heating at 150 ° C. for 2 hours.
The diffraction efficiency for light of 0 nm was greatly reduced from 12% to 1%. The grating depth also decreased from 0.3 μm to less than 0.1 μm.

In Comparative Examples D, E and I, (c)
Instead of dissolving and removing the unreacted compound (B) with a solvent in the step, the unreacted compound (B) was evaporated (or sublimated) by heating under reduced pressure or normal pressure. The grating depths of the diffraction gratings obtained in these comparative examples are extremely small, and the wavelength of these diffraction gratings is 780 nm.
The diffraction grating for the light of 1% was 1%. In order to produce a diffraction grating having a diffraction efficiency of 12% for light having a wavelength of 780 nm by removing the unreacted compound (B) in the same manner as in Comparative Examples D, E and I above, As shown by F, much longer exposure time was required than in the present invention. In Table 4, parts are parts by weight.

[Table 4]

[0044]

According to the present invention, the exposed portion of the thin film made of the photosensitive resin composition has a surface relief structure having a higher refractive index and a larger thickness than the unexposed portion, and has excellent heat resistance. Pattern can be produced with high productivity by a short exposure time.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-48202 (JP, A) JP-A-3-1145 (JP, A) JP-A-62-95526 (JP, A) JP-A-62-95 95525 (JP, A) JP-A-62-174703 (JP, A) JP-A-58-54337 (JP, A) JP-A-56-137348 (JP, A) (58) Fields investigated (Int. ^6, DB name) G03F 7/027 G03F 7/004 G03F 7/40

Claims (1)

(57) [Claims] (A) The following general formula (I): [In the formula, X ¹ represents a hydrogen atom or an alkyl group, and Y ¹ represents a cycloalkenyl group or the following general formula (III). 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. 2 to 100 mol% of the structural unit represented by the following general formula (II): [In the formula, 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 general formula (II) may be substituted by a fluorine atom. Comprising a polymer (A) having 0 to 98 mol% of a structural unit represented by the formula (I) and a compound (B) selected from the group consisting of an aromatic aldehyde and an aromatic ketone which may have a substituent. Forming a thin film of a conductive resin composition, (b) partially irradiating the thin film with ultraviolet rays according to a desired pattern, (c)
Dissolving and removing the unreacted compound (B) from the thin film using a solvent in which the polymer (A) is not dissolved; and (d)
A step of irradiating the entire surface of the thin film with ultraviolet rays.