JPH0862842A - Composition, photosensitive resin, pattern, and pattern forming method using the same - Google Patents

Abstract

PURPOSE: To obtain a pattern of a surface relief structure having a large difference in unevenness between an exposure part and a non-exposure part and a sinusoidal wave like smooth shape by incorporating a specific compound and a polymer or copolymer. CONSTITUTION: Five to ninety weight percent compound (A) having a structural unit expressed by formula I and 10-95% polymer or copolymer having 2-98mol% structural unit expressed by formula II are incorporated. In the formula I, each of R1 and R6 is hydrogen atom or a group expressed by formula, CF2m CF3 (where, m is an integer of 1-3), and not all of R1 -R6 are hydrogen atoms and n is an integer of 1-6. In the formula II, R7 is hydrogen atom or a <=4C alkyl group, R8 is a cycloalkenyl group or a group expressed by formula III. In the formula III, each of R9 -R11 is hydrogen atom or an alkyl group and Z is an integer of 1-5.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a photosensitive composition,
The present invention relates to a photosensitive resin capable of producing a pattern having a large difference in unevenness, a pattern using the same, and a pattern producing method.

[0002]

2. Description of the Related Art Most of the conventionally known photosensitive resins are
It is composed of a compound having a photosensitive group and a polymer compound, or is a polymer compound having a photosensitive group, and a cross-linking reaction or a molecule disintegration reaction occurs in the exposed part of the photosensitive resin, making the exposed part difficult. Since it is solubilized or easily solubilized, a pattern was formed by a method [conventional method (1)] of removing the photosensitive resin in the exposed or unexposed area with a solvent.

Further, a thin film is formed from a photosensitive resin composition obtained by doping a resin with a relatively volatile photoreactive substance having a refractive index higher than that of the resin, and then the thin film is irradiated with ultraviolet rays to be exposed. Method for forming a pattern having a refractive index difference between the exposed portion and the non-exposed portion by locking the doped material in the exposed portion and removing the doped material in the non-exposed portion by evaporation, so-called photo-locking method [conventional method (2) ] Is known [Applied Physics Letters (Appli
ed Physics Letters), Volume 26,
No. 6, pp. 303-306 (1975)]. According to this method, it is reported that the film thickness in the exposed part is increased by about 10% as compared with the non-exposed part.

Further, an acrylic acid or methacrylic acid ester-based polymer compound having a photoreactive double bond in the alcohol residue of the ester and an aromatic ketone having a large molecular volume and a higher refractive index than the polymer compound. Or an aromatic aldehyde (eg, 3-benzoylbenzophenone)
A thin film is formed from a photosensitive resin composition consisting of, and then the thin film is irradiated with ultraviolet rays, and then the unreacted aromatic ketone or aromatic aldehyde is removed to form a gap between the exposed portion and the non-exposed portion. A method [conventional method (3)] for producing a pattern having a difference in refractive index (about 0.04) and a difference in unevenness (about 30%) is known (Japanese Patent Laid-Open No. 62-955).
25 and JP-A-62-95526).

[0005]

The conventional method (1) corresponds to an exposed portion and an unexposed portion by utilizing the fact that the solubility of the photosensitive resin composition in a developing solution is different at a certain exposure amount. Since the formed pattern is formed, the formed pattern has a rectangular shape, and it is difficult to form a pattern having a smooth shape such as a sine wave. According to the conventional method (2), a pattern having a difference in refractive index between the exposed portion and the non-exposed portion and a change in thickness of the uneven portion can be obtained, but the change width of the unevenness is slight. According to the conventional method (3), it is possible to form a pattern in which the exposed portion of the photosensitive resin composition has a higher refractive index than the non-exposed portion and has a large thickness, and the thickness and the refractive index are changed depending on the exposure amount. Since it can be changed continuously, it is possible to create a pattern having a sinusoidal, gentle shape, but depending on the application, it is desired that the difference in refractive index is small and that there is a larger unevenness difference. was there.

The present invention is a composition from which a pattern having a large relief difference between an exposed portion and a non-exposed portion and having a surface relief structure having a smooth shape such as a sinusoidal shape can be obtained. It aims at providing the photosensitive resin which becomes. Another object of the present invention is to provide a method for producing the above pattern using the photosensitive resin composition. A further object of the present invention is to provide a pattern made of the photosensitive resin composition.

[0007]

According to the present invention, the above-mentioned object is to achieve the structural unit represented by the following general formula (I) (hereinafter,
This is called structural unit (I). 5 to 90% by weight of the compound (A) having a structural unit represented by the following general formula (II) (hereinafter, this is referred to as a structural unit (II). Further, it is represented by the following general formula (III). The polymer or copolymer having 2 to 98 mol% of the structural unit is referred to as a structural unit (III) (hereinafter, simply referred to as "polymer (B)").
It is achieved by providing a composition characterized by containing 10 to 95% by weight or a photosensitive resin comprising the composition. Structural unit (I):

[Chemical 13] Structural unit (II):

Embedded image

The composition ratio of the compound (A) to the polymer (B) is preferably in the range of 5:95 to 90:10 (weight ratio), and in the range of 20:80 to 80:20 (weight ratio). More preferable.

Further, according to the present invention, the above object is to provide a compound (C) having a structural unit represented by the following general formula (IV) (hereinafter referred to as structural unit (IV)) in an amount of 5 to 5: 9
0% by weight and a structural unit represented by the following general formula (V) (hereinafter referred to as a structural unit (V). A structural unit represented by the following general formula (VI) is referred to as a structural unit (VI). 10) to a polymer or a copolymer having 2 to 98 mol% (hereinafter, simply referred to as “polymer (D)”).
It is achieved by providing a composition characterized by comprising by weight or a photosensitive resin comprising the composition. Structural unit (IV):

[Chemical 15] Structural unit (V):

Embedded image

The composition ratio of the compound (C) to the polymer (D) is preferably in the range of 5:95 to 90:10 (weight ratio), and in the range of 20:80 to 80:20 (weight ratio). More preferable.

Examples of the compound (A) or the compound (C) include derivatives of benzaldehyde or benzophenone even if they have a substituent, and preferred compounds include 3,3'-ditrifluoromethylbenzophenone and (3 ′ -Trifluoromethylbenzoyl) -3-
Trifluoromethylbenzophenone, 4'-trifluoromethylbenzoyl-4-trifluoromethylbenzophenone, 3'-trifluoromethylbenzoyl-4-trifluoromethylbenzophenone, 3'-trifluoromethylbenzoyl-3,5-bistrifluoromethyl Benzophenone, 3 ', 5'-bistrifluoromethyl-
3,5-bistrifluoromethylbenzophenone, 3,
3'-bisperfluoroethylbenzophenone, 3'-
Perfluoroethylbenzoyl-3-perfluoroethylbenzophenone, 4'-perfluoroethylbenzoyl-4-perfluoroethylbenzophenone, 3'-perfluoroethylbenzoyl-4-perfluoroethylbenzophenone, 3'-trifluoromethylbenzoyl- 3-perfluoroethylbenzophenone, 4'-trifluoromethylbenzoyl-4-perfluoroethylbenzophenone, 3'-trifluoromethylbenzoyl-
4-perfluoroethylbenzophenone, 3'-perfluoroethylbenzoyl-4-trifluoromethylbenzophenone, 1,3,5-tris- (3'-trifluoromethylbenzoyl) -benzene, 1,3,5-tris- (4'-trifluoromethylbenzoyl) -benzene. Among these, 3- (3'-trifluoromethylbenzoyl) -3-trifluoromethylbenzophenone, 3- (4'-trifluoromethylbenzoyl) -4-trifluoromethylbenzophenone, 1,
3,5- (tri- (3'-trifluoromethylbenzoyl)) benzene and 3- (3 ', 5'-ditrifluoromethylbenzoyl) -3,5-ditrifluoromethylbenzophenone are easy to synthesize, It is preferable in terms of high reactivity.

Examples of the alkyl group having 4 or less carbon atoms represented by R ₇ in the structural unit (II) or R ₂₁ in the structural unit (V) include a methyl group, an ethyl group, a propyl group, an isopropyl group and a butyl group. Can be mentioned. The alkyl group represented by R ₉ , R ₁₀ and R ₁₁ in the structural unit (III) or R ₂₃ , R ₂₄ and R ₂₅ in the structural unit (VI) may have a branched chain or any substituent. A lower alkyl group having 8 or less carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, amyl group, hexyl group, heptyl group and octyl group is preferable. Preferable examples of R ₈ in the structural unit (II) or R ₂₂ in the structural unit (V) 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, isoperanyl group, neryl group, lavandulyl group, 6-methylgeranyl group, 1-methylgeranyl group,
6-ethylgeranyl group, perylyl group, farnesyl group,
Examples thereof include geranylgeranyl group and β-cyclogeranylgeranyl group.

The polymer (B) or the polymer (D) is an acrylic acid or an ester thereof which may be substituted by an alkyl group at the α-position, or an acrylic acid or an ester thereof and a structural unit (III) or a structural unit (VI). It can be produced by copolymerization with a comonomer forming a) to obtain a polymer, and then reacting the polymer with an alcohol having a group R ₁₁ .

As the acrylic acid derivative forming the structural unit (II) or the structural unit (V), 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,
Acrylic acid derivative in which alcohol residues such as 2 (or 3) -methyl-2-heptenyl methacrylate and 2 (or 3) -methyl-2-heptenyl acrylate are chained; 2 (or 3) -methyl 2-cyclohexenyl methacrylate, acrylic acid derivative having a cyclic alcohol residue such as 2 (or 3) -methyl-2-cyclohexenyl acrylate; geranyl methacrylate, geranyl acrylate, neryl methacrylate,
Neryl acrylate, isogenanyl methacrylate, isogenanyl acrylate, lavandulyl methacrylate, lavandulyl acrylate, 6-methylgeranyl methacrylate, 6-methylgeranyl acrylate, 1
-Methylgeranyl methacrylate, 1-methylgeranyl acrylate, 6-ethylgeranyl methacrylate, 6
An ester of a chain or cyclic terpene alcohol having two non-conjugated double bonds such as ethylgeranyl acrylate, perillyl methacrylate, perylyl acrylate and acrylic acid or methacrylic acid; farnesyl methacrylate, farnesyl acrylate, Geranylgeranyl methacrylate, geranylgeranyl acrylate, β
-A non-conjugated double bond such as cyclogeranylgeranyl methacrylate or β-cyclogeranylgeranyl acrylate is bonded to
Examples thereof include esters of chain-like or cyclic terpene-based alcohols having one or more and acrylic acid or methacrylic acid. Among these, allyl methacrylate, 2-propenyl methacrylate, 2-methyl-2-propenyl methacrylate, 2-butenyl methacrylate, 2-methyl-2-butenyl methacrylate, 2-hexenyl methacrylate, 3-hexenyl methacrylate, geranyl methacrylate. However, it is preferable from the viewpoint of easy availability of alcohol as a raw material and ease of ester synthesis.

Methacrylic acid as a comonomer forming the structural unit (III) or the structural unit (VI); methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, amyl methacrylate. , Methacrylic acid alkyl esters such as cyclohexyl methacrylate;
Acrylic acid; acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, amyl acrylate, cyclohexyl acrylate; methacrylic acid amide, acrylic acid amide, styrene And substituted styrenes such as α-methylstyrene. The hydrogen atom in the structural unit (III) or the structural unit (VI) may be substituted with a fluorine atom.

The polymer (B) or the polymer (D) has a polystyrene-equivalent number average molecular weight of 1,000 to 2,000,0 determined by gel permeation chromatography.
Those in the range of 00 are preferable. The polymer (B) or the polymer (D) has a number average molecular weight of 100,000 to 1,5.
Those in the range of 0,000 are more preferable.

According to the present invention, one of the other objects mentioned above is characterized by comprising the following steps (a), (b) and (c): It is achieved by providing a patterning method using. (A) A step of forming a thin film of the above composition. (B) A step of partially irradiating the thin film with ultraviolet rays according to a desired pattern. (C) A step of removing unreacted compounds from the thin film.

In the step (a), the compound (A) and the polymer (B) (or the compound (C) and the polymer (D)) are dissolved in a solvent which dissolves them, and the resulting solution is used. A thin film is formed by a casting method, a bar coating method, a spin coating method, or the like. The solvent is removed from the thin film by subjecting the thin film to reduced pressure treatment or heat treatment, if necessary. The method of forming the thin film is selected according to the desired degree or thickness of the thin film. The thickness of the thin film is preferably in the range of 0.1 to 20 μm. Generally, when the thickness is large, the casting method is used, and when the thickness is small, the bar coating method or the spin coating method is used.

In the step (b) following the step (a), the wavelength of the thin film is partially 200 to 450 depending on a desired pattern.
Irradiate with ultraviolet rays of nm. This gives the structural unit (I
I) and compound (A) (or structural unit (V) and compound (C)) undergo photoreaction. High pressure mercury lamp, N
_{A two} gas laser, a He-Cd laser, or the like is used. As a method for 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 adopted.

The removal of the unreacted compound (A) (or compound (C)) in the step (c) following the step (b) is carried out by reducing the thin film under reduced pressure at a temperature in the range of 20 to 120 ° C. for 15 to 30 ° C.
Heat treatment (hereinafter referred to as pre-heat treatment) for a period of time, and then heat treatment at a temperature in the range of 105 to 230 ° C. for 15 minutes to 40 hours under normal pressure (hereinafter referred to as post-heat treatment).
Or a pre-heat treatment, and then the whole surface of the thin film of the photosensitive resin composition is exposed to ultraviolet rays having a strength of 10 to 40 mW / cm ² and a wavelength of 200 to 450 nm for 10 seconds to 10 minutes. It is preferable to perform irradiation for a minute. As a result, a pattern having a desired unevenness difference is obtained. More preferably, the post-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. Further, it is preferable to carry out post-heat treatment and then UV irradiation after the above-mentioned pre-heat treatment, since a pattern having further organic solvent resistance and heat resistance can be obtained. When the above preheat treatment is performed at a temperature in the range of 100 to 120 ° C. for 15 to 30 hours, a pattern having high organic solvent resistance and heat resistance can be obtained even if the above post heat treatment is omitted.

From the photosensitive resin composition by the above method,
A pattern such as an optical waveguide, a diffraction grating, a grating lens, a Fresnel lens, and a hologram lens can be produced. Further, by doping the photosensitive resin composition with various nonlinear optical materials, an optical waveguide having a nonlinear effect can be produced. The patterns are extremely excellent in optical transparency and heat resistance.

Further, by using the pattern obtained by the present invention as a master mold and utilizing the 2P method, the injection molding method or the like, a large number of replicas can be reproduced.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples. First, four kinds of compounds (A) were synthesized by the following methods.

Synthesis Example 1 (Synthesis of 3- (3'-trifluoromethylbenzoyl) -3-trifluoromethylbenzophenone) 50 g of 3-bromotrifluoromethylbenzene, 5.7 g of magnesium and tetrahydrofuran (THF) 1
3-Bromomagnesium-trifluoromethylbenzene was synthesized from 80 ml by Grignard reaction, and 18.9 g of isophthaloyl chloride and 180 ml of THF were synthesized.
Was added dropwise at -78 ° C. After that, the reaction solution was returned to room temperature and stirred for 24 hours, water was added, and the mixture was extracted with ether to 3 times.
The organic layer was dried and dried over magnesium sulfate. After removing the solvent under reduced pressure, the target substance was purified from the solid substance by a column chromatography method.

Synthesis Example 2 (Synthesis of 3- (4'-trifluoromethylbenzoyl) -4-trifluoromethylbenzophenone) In Synthesis Example 1, 4-bromotrifluorobenzene was used instead of 3-bromotrifluoromethylbenzene. , Was synthesized in the same manner.

Synthesis Example 3 (1,3,5- (tri- (3 '
-Trifluoromethylbenzoyl)) Synthesis of benzene) A Grignard reagent was prepared from 50 g of 3-bromotrifluoromethylbenzene, 5.7 g of magnesium and 180 ml of THF, and 16.6 g of 1,3,5-benzenetricarbonyltrichloride was prepared. It was added dropwise to a solution of 180 ml of THF. Then, the target product was obtained in the same manner as in Synthesis Example (1).

Synthesis Example 4 (Synthesis of 3- (3'-5'-ditrifluoromethylbenzoyl) -3,5-ditrifluoromethylbenzophenone) A Grignard reagent was prepared from 1,3-dibromobenzene and magnesium. The desired product was obtained in the same manner as in Synthesis Example (1) by reacting with 3,5-ditrifluoromethylbenzoyl chloride.

Example 1 2-butenyl methacrylate 7 after substitution with N _{2 in a} reaction vessel
0 g, 10 g of methyl methacrylate, 600 mg of azobisisobutyronitrile, and 900 ml of dioxane were charged, sealed, and heated in a water bath at 53 ° C. for 24 hours to carry out a polymerization reaction. Methanol 4l
The mixture was poured into the flask, the product was precipitated, and dried to obtain 150 g of a polymer (B). This polymer (B) is NMR
It was confirmed from the measurement results by the copolymer that the molar ratio of 2-butenyl methacrylate to methyl methacrylate was 1: 3. The polystyrene-reduced number average molecular weight of this polymer (B) determined by gel permeation chromatography was 250,000. Compound (A) (aromatic ketone) synthesized in Synthesis Example 1 above.
A composition consisting of 8 parts and 1 part of the polymer (B) was dissolved in toluene, and the obtained solution was used to form a thin film (thickness: 2.5 μm) on a glass substrate by spin coating.
After baking this thin film at 70 ° C. for 0 hour,
Ultraviolet rays of 25 mW / cm ² were irradiated for 5 minutes through a photo mask having a line-and-space of μm cycle.
After irradiation, remove the photo mask, and in a vacuum dryer at 95 ° C,
By performing heat treatment for 15 hours under the condition of 0.2 mmHg, the unreacted compound (A) was removed to prepare a diffraction grating pattern. When the pattern of the obtained diffraction grating was measured using a Taly step, the step difference between the concave portion and the convex portion was 1.0 μm. In addition, the pattern was substantially sinusoidal. The maximum refractive index of the convex portion is 1.51.
5, the minimum refractive index of the recess was 1.505.

Example 2 Using the thin film prepared in Example 1, the distance between the photomask having a 60 μm cycle and the thin film was set to 15 μm, and ultraviolet rays (25 m
W / cm ² ) was irradiated for 10 minutes. Subsequently, unreacted compound (A) was removed by performing heat treatment for 15 hours in a vacuum dryer at 95 ° C. and 0.2 mmHg. The shape of the obtained relief pattern was already sinusoidal, the unevenness was continuously changed, and the diffraction efficiency of the first-order light to the zero-order light in the diffraction grating was 100%. The step between the concave and convex portions of this diffraction grating is 1.0
was μm. The maximum refractive index of the convex portion and the concave portion was the same as in Example 1.

Examples 3 to 6 By the same method as in Example 1, a photosensitive resin composition comprising the compound (A) shown in Table 1 and the polymer (B) was prepared and shown in Table 1. A diffraction grating was produced under the same conditions as in Example 1 using the photosensitive resin composition having the composition. Table 1
In addition, the measurement results and the like of the step between the concave portion and the convex portion in each example are also shown.

[Table 1]

[0031]

According to the present invention, the photosensitive resin having a large unevenness difference between the exposed portion and the non-exposed portion of the photosensitive resin and capable of forming a surface relief pattern having a smooth shape such as a sine wave shape. A resin composition is obtained. Further, a method for producing the above pattern using the photosensitive resin composition and a pattern produced by the photosensitive resin composition are obtained. Particularly in the present invention, having a large unevenness difference, and
Since it is possible to obtain a sinusoidal pattern, a diffraction grating having extremely high diffraction efficiency can be manufactured.

Claims (8)

[Claims] 1. The following general formula (I): 5 to 90% by weight of a compound having a structural unit represented by
And the following general formula (II): A composition comprising 10 to 95% by weight of a polymer or copolymer having 2 to 98 mol% of the structural unit represented by. 2. The following general formula (I): 5 to 90% by weight of a compound having a structural unit represented by
And the following general formula (II): A photosensitive resin, comprising a composition containing 10 to 95% by weight of a polymer or copolymer having 2 to 98 mol% of the structural unit represented by. 3. A pattern made of the photosensitive resin according to claim 2. 4. The following general formula (I): 5 to 90% by weight of a compound having a structural unit represented by
And the following general formula (II): A step of forming a thin film of a photosensitive resin composition containing 10 to 95% by weight of a polymer or copolymer having 2 to 98 mol% of the structural unit shown in, (b) partial formation of the thin film according to a desired pattern And a step of removing the unreacted compound from the thin film. 5. The following general formula (IV): 5 to 90% by weight of a compound having a structural unit represented by
And the following general formula (V): A composition comprising 10 to 95% by weight of a polymer or copolymer having 2 to 98 mol% of the structural unit represented by. 6. The following general formula (IV): 5 to 90% by weight of a compound having a structural unit represented by
And the following general formula (V): A photosensitive resin, comprising a composition containing 10 to 95% by weight of a polymer or copolymer having 2 to 98 mol% of the structural unit represented by. 7. A pattern made of the photosensitive resin according to claim 6. 8. (a) The following general formula (IV): 5 to 90% by weight of a compound having a structural unit represented by
And the following general formula (V): A step of forming a thin film of a photosensitive resin composition containing 10 to 95% by weight of a polymer or copolymer having 2 to 98 mol% of the structural unit shown in, (b) partial formation of the thin film according to a desired pattern And a step of removing the unreacted compound from the thin film.