JP2000258909A - Photosensitive resin composition and pattern forming method using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photosensitive polyimide resin composition excellent in stability and photosensitivity. SOLUTION: The photosensitive resin composition contains a carboxyl- containing resin and an arene compound of the formula [(Ar)(CpM)2]2+2X-, wherein Ar is aromatic π-arene to which two or more metal-cyclopentadienyl compounds can coordinate, Cp is an anion of cyclopentadiene, M is a cation of the metal and X- is at least one selected from the group consisting of SbF6-, BF4-, AsF6- and PF6-.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photosensitive resin composition having excellent stability and photosensitivity, and a pattern forming method using the same.

[0002]

2. Description of the Related Art Pattern formation in semiconductor device manufacturing,
Alternatively, in the production of a color filter used for a liquid crystal display, an imaging device, and the like, the need for a photosensitive resin having excellent stability and photosensitivity has been significantly increased.
In addition, resistance to the heat applied during the manufacturing process and during use is required.

[0003] A large number of photosensitive resins have been proposed and put into practical use, but in recent years, patterning is possible without using a photoresist, and after curing, the resin is physically and chemically cured. 2. Description of the Related Art A photosensitive polyimide resin, which has an advantage that a layer having stability and excellent heat resistance can be formed, has been attracting attention.

Photosensitive polyimide resins include those obtained by introducing a photosensitive group into a soluble polyamic acid, which is a precursor of polyimide, and those obtained by directly introducing a photosensitive group into a solubilized polyimide. That is, many have negative characteristics. Further, a positive photosensitive polyimide resin in which an o-nitrobenzyl group has been introduced into a polyimide precursor has also been reported.

As another positive photosensitive resin, a resin in which a specific metal complex is blended with an acrylic resin, a phenolic resin, a polyester resin, or a polyurethane resin has been proposed (Japanese Patent Application Laid-Open No. 10-153863). .

[0006]

The above-mentioned photosensitive polyimide has a structure in which a photosensitive group is introduced into a polyimide resin precursor. In the case of a negative type, a portion irradiated with light is insoluble. In the case of a positive type, since it becomes soluble, there is an advantage that patterning is possible without using a photoresist. However, conventionally known photosensitive polyimides cannot be said to be sufficient in terms of stability and photosensitivity, and improvements in this respect are strongly desired.

The present invention has been made in response to such demands, and has as its object to provide a photosensitive polyimide resin composition having excellent stability and photosensitivity.

[0008]

Means for Solving the Problems The photosensitive resin composition of the present invention
The product is basically a tree with a carboxyl group in the molecule.
Fat and the following general formula (1) [(Ar) (CpM)_Two]²⁺2X^-... (1) (wherein Ar is a metal cyclopentadienyl compound of 2
Or more aromatic π-arenes, Cp
M is an anion of antadiene, M is a cation of a metal, X ^-Is S
bF₆ ^-, BF_Four ^-, AsF₆ ^-And PF₆ ^-From the group consisting of
Any one selected. Arene represented by)
It consists of a compound.

In the present invention, any resin having a carboxyl group in the molecule and capable of forming a film can be used.
Generally, it is a substance called a polyimide precursor. The photosensitive resin composition of the present invention is constituted by adding the above arene compound to the resin having a carboxyl group in the molecule.

Specific examples of arene compounds to which two or more metal dicyclopentadienyl compounds can be coordinated include the following compounds.

[0011]

Embedded image These arene compounds may be used alone,
If necessary, two or more kinds can be used in any combination.

One feature of the present invention is that, unlike the conventional negative photosensitive polyimide resin, it has a positive photosensitive property. Positive photosensitive resins are suitable for forming fine patterns in that they have little film loss during development and high dimensional stability. Also,
Unlike the case where a photosensitive group is introduced into the molecule, since the arene compound is only added to the carboxyl group-containing resin, there are a wide range of options for the molecular structure of the carboxyl group-containing resin, for example, a commercially available non-photosensitive polyimide precursor Has the advantage that the photosensitivity can be easily provided.

The photosensitive resin composition of the present invention can be widely applied to pattern formation using a carboxyl group-containing resin, for example, a color filter of a color LCD.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The photosensitive resin composition of the present invention comprises a resin having a carboxyl group in the molecule and an arene compound added at an appropriate ratio thereto. In actual use, a predetermined amount of an arene compound is added to a carboxyl group-containing resin solution to form a photosensitive varnish, which is applied to the surface of an arbitrary substrate and dried to form a photosensitive film. When the photosensitive film is irradiated with a light beam through a mask having an arbitrary pattern, the portion not irradiated with the light (unexposed portion) has reduced solubility due to the effect of the arene compound, but the irradiated portion ( In the exposed part), the solubility is not reduced because the arene compound is decomposed by light and its effect is lost.
After exposure, partial imidization is performed by heating, the solubility is adjusted, and then development is performed with a developer composed of an alkaline aqueous solution.
The exposed portion is dissolved and removed by the difference in solubility, so that a pattern corresponding to the pattern of the mask is formed.

In the photosensitive resin composition of the present invention, what kind of reaction occurs due to exposure has not been theoretically elucidated yet, but in an unexposed portion, an arene compound is added to the carboxyl group of the carboxyl group-containing resin. By coordinating, the solubility of the carboxyl group-containing resin decreases, while in the exposed area, the arene compound is decomposed,
It is presumed that the decrease in solubility does not occur without coordination and the solubility is maintained.

Since the arene compound of the present invention has two coordination points, the resins are cross-linked via the arene compound, whereby the resin structure becomes three-dimensional and the apparent molecular weight increases. As a result, the difference in solubility between the exposed part and the unexposed part increases, and the photosensitive resin exhibits excellent developability.

In the present invention, the polyimide precursor is generally referred to as a polyimide precursor produced by reacting a diamine with an aromatic tetracarboxylic dianhydride, as is well known in the art. Substantially all substances can be used as long as they have the following general formula (2):

[0018]

Embedded image It is represented by

The diamine is represented by the following general formula (3)

[0020]

Embedded image Aromatic diamines, aliphatic diamines and alicyclic diamines represented by are included, and particularly suitable are, for example, metaphenylenediamine, paraphenylenediamine, 4,
4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 2,2'-bis (4-aminophenyl) propane, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4 ' −
Diaminodiphenyl sulfide, benzidine, benzidine-3,3'-dicarboxylic acid, benzidine-3,3'-disulfonic acid, benzidine-3-monocarboxylic acid, benzidine-3-monosulfonic acid, 3,3'-dimethoxy-benzidine And aromatic diamines such as para-bis (4-aminophenoxy) benzene, meta-bis (4-aminophenoxy) benzene, meta-xylylenediamine and para-xylylenediamine, and among them, 4,4'-diaminodiphenyl ether, , 3'-Diaminodiphenylsulfone and 4,4'-diaminodiphenylsulfone are preferably used.

When the photosensitive resin composition of the present invention is applied to the surface of a glass substrate, when a diamine containing silicon in the molecule is used in an amount of about several percent, the adhesion to the glass substrate surface is increased. Is preferred. Examples of such silicon-containing diamines include:

[0022]

Embedded image And the like.

In the present invention, the aromatic tetracarboxylic dianhydride to be polymerized with the diamine is represented by the following general formula (5):

[0024]

Embedded image Can be used. In particular,
Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-
Biphenyltetracarboxylic dianhydride, 2,3,3 ',
4 'biphenyltetracarboxylic dianhydride, 2,3
6,7-naphthalenetetracarboxylic dianhydride, 1,
2,5,6-naphthalenetetracarboxylic dianhydride,
1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl)
Propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride 2-2'-bis (2,3
-Dicarboxyphenyl) propane dianhydride, 1,1 ′
-Bis (2,3-dicarboxyphenyl) ethane dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1 , 2,7,8-phenanthrenetetracarboxylic dianhydride and the like. Among them, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′ , 4,4'-biphenyltetracarboxylic dianhydride is suitable.

The polymerization reaction of the diamine with the aromatic tetracarboxylic dianhydride can be carried out according to a conventionally known method. For example, the reaction is carried out in a nitrogen gas stream while controlling the temperature to 60 ° C. or lower, preferably 30 ° C. or lower in the presence of an organic solvent.

Examples of the organic solvent include N-methyl-2-pyrrolidone, N, N'-dimethylacetamide,
Highly polar basic solvents such as N, N'dimethylformamide, dimethylsulfoxide, hexamethylphosphoramide and the like are used. All of these types of solvents have high hygroscopicity, and the absorbed water causes a decrease in molecular weight during polymerization and a decrease in storage stability. Therefore, it is desirable to sufficiently dehydrate with a dehydrating agent prior to use. . If necessary, an organic solvent such as toluene, xylene, benzonitrile, benzene or phenol can be used together with these solvents.

The polyimide precursor thus obtained has, as shown in the above-mentioned general formula (1), a bonding unit obtained by adding a diamine to an aromatic tetracarboxylic dianhydride via an amide bond. It has a structure that is randomly bonded.

The arene compound added to such a polyimide precursor is a compound represented by the aforementioned general formula (1).

In the general formula (1), π- represented by Ar
As arenes, metal cyclopentadienyl compounds
Is capable of coordinating two or more, and particularly has 12 to 24 carbon atoms.
Aromatic compounds or heteroaromatics having 6 or more carbon atoms
Group compounds whose groups are unsubstituted
Or the same or different monovalent groups, such as
If halogen atom, C₁~ C₈Alkyl group, C₁~ C₈Arco
Xy group, cyano group, C ₁~ C₈Alkylthio group, C_Two~ C₆
Monocarboxylic acid ester group, C_Two~ C₆Alkanoyl group
Therefore, it can be mono- or polysubstituted. These π-arrays
The monocyclic group may be a single ring, a condensed polycyclic, or a non-condensed polycyclic
In the case of a non-fused polycyclic ring, the aromatic ring is directly bonded.
Or a crosslinking group such as -S- or -O-
They may be connected via a link.

The substituents of the alkyl, alkoxy, alkylthio, alkyl monocarboxylate, and alkanoyl may be linear or branched. Representative alkyl, alkoxy, monocarboxylic acid alkyl ester, and alkanoyl substituents are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-pentyl, respectively. Hexyl, and n-octyl; methoxy, ethoxy, n-propoxy, isopropoxy, n-putoxy, n-hexyloxy, and n-octyloxy;
Methylthio, ethylthio, n-propylthio, isopropylthio, n-butylthio, n-benzylthio, and n-hexylthio; methyl carboxylate, ethyl carboxylate, n-propyl carboxylate, isopropyl carboxylate, n-carboxylate
Butyl ester, and carboxylic acid n-pentyl ester; and acetyl, propionyl, and butyryl. The alkyl, alkoxy, alkylthio, and monocarboxylic acid alkyl ester groups preferably have from 1 to 4, especially 1 or 2 carbon atoms in the alkyl portion thereof, and the alkanoyl group has 2 or 3 carbon atoms. It preferably has carbon atoms.

Specific examples of suitable π-arenes include biphenyl, fluorene, phenanthrene, anthracene, 9,
10-dihydroanthracene, triphenylene, pyrene, naphthacene, xanthene, thioxanthen, thianthrene, diphenylene oxide, diphenylene sulfite, acridine, phenothiazine, phenoxazine, binaphthyl, biphenyl, diphenylmethane, diphenylethane and carbazole.

In the general formula (1), M is preferably a cation of chromium, cobalt, manganese, tungsten, iron or molybdenum, particularly preferably a cation of iron. Most preferred is Fe ²⁺ .

The compound of the general formula (1) can be synthesized by a conventionally known method.

In the present invention, the amount of the arene compound to be added to the carboxyl group-containing resin is not particularly limited, but is preferably 1 to 100% by weight, more preferably 3 to 100% by weight, based on the solid content of the carboxyl group-containing resin.
~ 80% by weight.

The photosensitive resin composition of the present invention is applied to the surface of a substrate by an appropriate means such as spin coating, and then applied at 100 ° C.
Evaporate the solvent under the following conditions, then, from a light source such as a mercury lamp, exposed through a mask of any pattern, and bake the substrate at 100 ~ 170 ℃, the solubility is reduced in the unexposed part, In the exposed area, the solubility remains high, and therefore, by washing with an alkaline solution such as a dilute aqueous sodium hydroxide solution, that is, by developing,
A positive pattern corresponding to the mask pattern remains.

By heating this pattern, the imidization of the remaining carboxyl group-containing resin proceeds, and a pattern having high chemical and mechanical strength is obtained. The baking between exposure and development is 3 ~
15 minutes, 15-6 when using a clean oven
About 0 minutes is optimal.

[0037]

[Example 1] 3.72 g of ferrocene (20 m
mol), 6.40 g (48 mmol) of AlCl ₃ , A
0.11 g (4 mmol), phenothiazine 0.80
g (4 mmol) and 50 ml of decalin were reacted in a flask in a nitrogen atmosphere while stirring at 150 ° C. for 4 hours. After the temperature was lowered to room temperature, 100 ml of water was added while cooling the flask with ice, and the mixture was stirred for 1.5 hours. After separating and filtering the aqueous layer, it was washed with cyclohexane, and NH ₄ PF ₆
A solution prepared by dissolving 8 g in 20 ml of water was added and stirred. The precipitate is suction-filtered and dried, and recrystallized from acetone / dioxane to give crystals of [η ⁶ , η ^6- phenothiazine] bis ([η ⁵ -cyclopentadienyl] iron (II)) dihexafluorophosphate. Obtained.

Polyimide precursor solution synthesized from 3,3 ', 4,4'-benzophenonetetracarboxylic acid and 3,3'-diaminodiphenylsulfone (resin content 14%) 1
1.75 g of the above-mentioned [η ⁶ , η ^6- phenothiazine] bis ([η ⁵ -cyclopentadienyl] iron (II)) dihexafluorophosphate was dissolved in 00 g, and a photosensitive varnish was prepared. This was spin-coated on glass at 800 rpm for 12 seconds, air-dried, and then heat-treated at 60 ° C. for 3 minutes,
The solvent was evaporated to form a film.

This film was exposed through a photomask with an ultra-high pressure mercury lamp. The exposure amount at this time was 1000 mJ in terms of the integrated amount of h-line. After processing at 150 ° C. for 5 minutes, development with a 0.2% aqueous sodium hydroxide solution yielded a positive pattern on the mask. This is 240
By performing the heat treatment at ℃, a stable polyimide film was formed.

Example 2 5.58 g of ferrocene (30
mmol), 9.60 g (72 mmol) of AlCl ₃ ,
Al 0.16 g (6 mmol), binaphthyl 1.52 g
(6 mmol) and 75 ml of methylcyclohexane were reacted in a flask in a nitrogen atmosphere while stirring at 90 ° C. for 20 hours. The post-treatment was carried out in the same manner as in Example 1, the precipitate was recrystallized from acetone / water, and [η ⁶ , η ⁶ -binaphthyl] bis ([η ⁵ -cyclopentadienyl] iron (I
I)) Dihexafluorophosphate crystals were obtained.

Polyimide precursor solution (resin content 14%) synthesized from 3,3 ', 4,4'-benzophenonetetracarboxylic acid and 3,3'-diaminodiphenylsulfone 1
00 g, the above-mentioned [η ⁶ , η ⁶ -binaphthyl] bis ([η
1.75 g of [ ⁵ -cyclopentadienyl] iron (II)) dihexafluorophosphate was dissolved to prepare a photosensitive varnish.

This photosensitive varnish was coated on glass at 800 rpm.
For 12 seconds, and then treated in the same manner as in Example 1 to obtain a polyimide film having a bodied pattern.

Comparative Example 1 [η] was added to 100 g of a polyimide precursor solution (resin content: 14%) synthesized from 3,3 ′, 4,4′-benzophenonetetracarboxylic anhydride and 3,3′-diaminodiphenylsulfone. ⁶ -naphthalene) (η ⁵
[Cyclopentadienyl] iron (II) hexafluorophosphate in an amount of 10 g to prepare a photosensitive varnish. This was spin-coated on glass at 800 rpm for 12 seconds and processed in the same manner as in Example 1 to obtain a positive pattern.

When the arene compound of the present invention obtained in Examples 1 and 2 and the arene compound of Comparative Example 1 are compared,
In the arene compound of Comparative Example 1, one cyclopentadienyl iron compound is coordinated with the π-arene,
In the arene compounds of Examples 1 and 2, the cyclopentadienyl iron compound is coordinated to the π-arene at two places. That is, in Examples 1 and 2, by coordinating the arene compound to the carboxyl group of the polyimide precursor at two coordination points, the polyimide precursors are cross-linked via the arene compound and the structure becomes three-dimensional. At the same time, the apparent molecular weight increases.

As a result, the difference in solubility between the exposed part and the unexposed part was larger than that in Comparative Example 1 in which the precursors did not have a crosslinked structure, and the residual film ratio during development of the photosensitive resin (film thickness after development) Was divided by the initial film thickness).

Table 1 below shows Examples 1 and 2 and Comparative Example 1.
2 shows a comparison of the remaining film ratio of the samples.

[0047]

[Table 1]

[0048]

As described above, the photosensitive resin composition of the present invention comprises a carboxyl group-containing resin and an arene compound in which a cyclopentadienyl iron compound is coordinated to a π-arene at two places. , The molecules of the carboxyl group-containing resin are cross-linked via the arene compound, the structure becomes three-dimensional, and the apparent molecular weight increases, so that the solubility difference between the exposed part and the unexposed part is reduced. As a result, the residual film ratio during the development of the photosensitive resin is significantly improved.

Therefore, the photosensitive resin composition has a remarkable effect in a wide range of fields including production of color filters. Further, in the present invention, it is not necessary to change the molecular structure in order to impart photosensitivity to the carboxyl group-containing resin, so that the carboxyl group-containing resin has high stability, and thus has an effect that a stable film can be obtained.

Furthermore, unlike ordinary photoresists, there is no need to use toxic chemicals such as hydrazine, and this has an extremely great advantage in terms of process control and environmental protection.

Further, the photosensitive resin composition of the present invention is applied to a substrate, dried, heated at a temperature higher than the drying temperature after exposure, and then developed to easily form a pattern corresponding to the pattern of the mask. It is possible to

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Claims (7)

[Claims] 1. A resin having a carboxyl group in a molecule.
And the following general formula (1) [(Ar) (CpM)_Two]²⁺2X^-... (1) (wherein Ar is a metal cyclopentadienyl compound of 2
Or more aromatic π-arenes, Cp
M is an anion of antadiene, M is a cation of a metal, X ^-Is S
bF₆ ^-, BF_Four ^-, AsF₆ ^-And PF₆ ^-From the group consisting of
Any one selected. Arene represented by)
A photosensitive resin composition comprising: 2. The polyimide precursor obtained by a polymerization reaction of a diamine and an aromatic tetracarboxylic dianhydride, wherein the resin having a carboxyl group in the molecule.
3. The photosensitive resin composition according to item 1. 3. The method according to claim 1, wherein M is iron (Fe).
3. The photosensitive resin composition according to item 1. 4. The method according to claim 1, wherein the diamine is 4,4′-diaminodiphenylether, 3,3′-diaminodiphenylsulfone, or 4,4′-diaminodiphenylsulfone. Photosensitive resin composition. 5. The method according to claim 1, wherein the aromatic tetracarboxylic dianhydride is pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, or 3,
The photosensitive resin composition according to any one of claims 1 to 4, which is 3 ', 4,4'-biphenyltetracarboxylic dianhydride. 6. The method according to claim 1, wherein the arene compound is anthracene,
The photosensitive resin composition according to any one of claims 1 to 5, wherein the photosensitive resin composition is at least one selected from the group consisting of pyrene, phenothiazine, phenoxazine, biphenyl, binaphthyl, diphenylmethane, and diphenylethane. . 7. A photosensitive resin composition according to claim 1, applied on a substrate, dried at a temperature of 100 ° C. or less to form a resin film, and then formed into a predetermined pattern. After exposure together and heating at a temperature of 100 to 170 ° C.,
A pattern forming method characterized by performing development.