JP2001288270A - Modified polysilsesquiazane, photosensitive composition, and method of forming patterned modified polysilsesquiazane film - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the stability of polysilsesquiazane,
Further, to enhance the storage stability and development efficiency of the photosensitive composition containing the present polymer. SOLUTION: General formula:-[SiR ¹ (NR ² ) _1.5 ]
- was the basic unit, further general formula: - [SiR ¹ ₂
NR ^2] - and / or _{^{[SiR 1 3 (NR 2) 0.}} 5 ] -
A number average molecular weight of 10 containing from 0.1 mol% to 100 mol% of other structural units represented by the formula:
0-100,000 modified polysilsesquiazane. (Wherein, R ¹ each independently represents an alkyl group having 1 to 3 carbon atoms or a substituted or unsubstituted phenyl group, and R ² each independently represents hydrogen, an alkyl group having 1 to 3 carbon atoms or a substituted phenyl group. Or represents an unsubstituted phenyl group.)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a novel modified polysilsesquiazane, a photosensitive composition containing such a modified polysilsesquiazane, and a modified composition patterned with such a photosensitive composition. The present invention relates to a method for forming a polysilsesquiazane film and an insulating film.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices and liquid crystal display devices, various elements including an interlayer insulating film are patterned. Such an element is generally exposed to a high temperature exceeding 400 ° C. in a manufacturing process of a semiconductor device or the like. Therefore, organic materials have insufficient heat resistance,
The use of inorganic materials is desired. As such an inorganic material,
The patterned silica-based ceramic film is useful in semiconductor devices, liquid crystal display devices, printed circuit boards, etc. as a film excellent in heat resistance, abrasion resistance, corrosion resistance, insulation, transparency, etc. in addition to heat resistance. It is known that

[0003] In particular, when a patterned film is used while remaining as an interlayer insulating film, a film excellent in low dielectric properties is desired. In response to such a request,
In the specification of Japanese Patent Application No. 11-283106, the present applicant discloses a step of forming a coating film of a photosensitive polysilazane composition containing polysilazane and a photoacid generator, and irradiating the coating film with light in a pattern. And a step of dissolving and removing the irradiated portion of the coating film, a method for forming a patterned polysilazane film and the patterned polysilazane film by leaving or firing in an ambient atmosphere. A method of forming a patterned insulating film, comprising a step of converting the film into a silica-based ceramic film, is disclosed. In the foregoing specification, the general formula as polysilazane - also discloses the use of at polysilsesquioxane sesqui Azan represented - [SiR ⁴ (NR ⁵⁾ _{1.5] n.}

[0004]

However, when polysilsesquiazane is used, the stability of the polymer itself is low, and in particular, polymethylsilsesquiazane- [SiCH
_{In the case of 3} (NH) _1.5 ] _n-, it was recognized that polymerization occurs between the polymers during storage due to the high reactivity of the polymers. Also, regarding the photosensitive composition containing polysilsesquiazane and a photoacid generator, some photoacid generators such as nitrobenzyl sulfonic acid ester may cause a trace amount of liberated polysilsesquiazane during storage. A phenomenon of decomposition by NH ₃ was also observed. Further, in order to increase the pattern development efficiency, it is necessary to promote the dissolution of polysilsesquiazane in the developer in the exposed area.

[0005]

Means for Solving the Problems The present inventor has proposed that the stability of the polymer itself can be improved by introducing a certain amount of a specific structural unit into the basic structural unit of polysilsesquiazane, and that the basic resistance to light can be improved. It has been found that the storage stability of the photosensitive composition is improved by selecting an acid generator, and that the development efficiency is further increased by adding a compound known as a dissolution inhibitor in the art, The present invention has been reached. That is, according to the present invention, (1) the general formula: - [SiR ¹ (NR ²⁾ _1.5] - was used as a basic unit, further general formula: - [SiR ¹ ₂ NR ^2]
- and / or [SiR ¹ ₃ (NR ²⁾ _0.5] - number containing 0.1 mol% to 100 mol% of other structural units to the basic unit represented by the average molecular weight 100 to 10
000 modified polysilsesquiazane (wherein R
¹ independently represents an alkyl group having 1 to 3 carbon atoms or a substituted or unsubstituted phenyl group; R ² each independently represents hydrogen, an alkyl group having 1 to 3 carbon atoms or a substituted or unsubstituted phenyl group; Represents [2] the modified polysilsesquiazane according to [1],
A photosensitive composition comprising a photoacid generator selected from the group consisting of a sulfoxime compound and a triazine compound; and [3] a step of forming a coating film of the photosensitive composition according to [2]. And irradiating the coating film with light in a pattern,
Dissolving and removing the irradiated portion of the coating film; and a method of forming a patterned modified polysilsesquiazane film.

[0006] Preferred embodiments of the present invention are listed below. [4] R ¹ is a methyl group and R ² is hydrogen;
The modified polysilsesquiazane according to item [1]. [5] The photosensitive composition according to [2], wherein the photoacid generator is 4-methoxy-α-((((4-methoxyphenyl) sulfonyl) oxy) imino) benzeneacetonitrile. [6] Further, t-butoxycarbonylated catechol,
Item [2], comprising an additive selected from the group consisting of t-butoxycarbonylated hydroquinone, benzophenone-4,4'-dicarboxylic acid t-butyl ester and 4,4'-oxydibenzoic acid t-butyl ester. The photosensitive composition as described in the above. [7] A pattern comprising a step of converting the patterned modified polysilsesquiazane film formed by the method according to [3] into a silica-based ceramic film by leaving or firing in an ambient atmosphere. Method for forming a simplified insulating film.

[0007] Modified polysilsesquioxane sesquicarbonate Azan of the present invention have the general formula: - [SiR ¹ (NR ²⁾ _1.5] - was used as a basic unit, further general formula: - [SiR ¹ ₂ NR ^2] - and /
Or [SiR ¹ ₃ (NR ²⁾ _0.5] - contain other structural units represented by. Here, R ¹ each independently represents an alkyl group having 1 to 3 carbon atoms or a substituted or unsubstituted phenyl group, and R ² each independently represents hydrogen, an alkyl group having 1 to 3 carbon atoms or a substituted or unsubstituted phenyl group. Represents an unsubstituted phenyl group.
These other building blocks are randomly linked to the base building blocks.

Specific groups for both R ¹ and R ² can be independently selected, and therefore may be the same or different between the basic structural units. It may be the same as or different from the structural unit. For example, a part of methyl R ¹ in the basic structural unit, that the remainder being phenyl, a part of R ² is hydrogen, that the remainder being methyl, and the R ¹ of the basic unit Methyl, and the other structural unit R ¹
Is methyl or phenyl, R ^{2 of the} basic structural unit
Is hydrogen, and R ² in the other structural unit is hydrogen or methyl. Preferably, in both the basic structural unit and other structural units, R ¹ is a methyl group or a phenyl group, and most preferably a methyl group. In both the basic structural unit and other structural units, R ² is preferably hydrogen.

[0009] Modified polysilsesquioxane sesquicarbonate Azan of the present invention have the general formula: - [SiR ¹ ₂ NR ^2] - and / or [SiR ¹
₃ (NR ² ) _0.5 ]-is 0.1 mol% to 100 mol%, preferably 0.5 mol% to 40 mol%, more preferably 1 mol% to the above-mentioned basic constitution unit. It contains from 20 mol% to 20 mol%. Formula Other structural units: - [SiR ¹ ₂ NR ^2] - in the case of containing only the content for the basic units is 0.1 mol%
It is preferably 100 mol%, more preferably 1 mol% to 20 mol%. In general formula as other structural units: [SiR ¹ ₃ (NR ²⁾ _0.5] - in the case of containing only the amount contained with respect to the basic units is 0.1 mol% to 50 mol%, more preferably It is preferably from 0.5 mol% to 20 mol%. When the amount of other structural units is less than 0.1 mol%, the stability of the polymer itself becomes low,
Upon storage, polymerization occurs between the polymers. On the other hand, if the amount of the other constituent units is more than 100 mol%, the molecular weight of the polymer will not be sufficiently high, and the coating film will have fluidity, which is not preferable.

The number average molecular weight of the modified polysilsesquiazane of the present invention is 100 to 100,000, preferably 500.
５5000. When the number average molecular weight of the modified polysilsesquiazane is lower than 100, fluidity is generated in the coating film. On the other hand, when the number average molecular weight is higher than 100,000, it becomes difficult to dissolve in a solvent.

The modified polysilsesquiazane of the present invention can be used
Ammonolysis in ordinary polysilazane synthesis
And R as a starting material¹SiCl_Three, R¹ _TwoSiCl_Two
And / or R¹ _ThreeSiCl and the latter two
By using the molar ratio corresponding to the content ratio of
Obtained easily. For example, as another structural unit, a general formula:
− [SiR¹ _TwoNR^Two]-When 20 mol% is contained
Has R¹SiCl_Three20 mol% of R¹ _TwoSi
Cl_TwoAmmonolysis using silane raw material mixed with
The same applies to the other structural units represented by the general formula: [S
iR¹ _Three(NR ^Two)_0.5]-Where 10 mol% is contained
If¹SiCl_Three10 mol% of R¹ _ThreeS
iCl may be mixed. When synthesizing polysilazane
For details of ammonolysis, see, for example, the applicant.
See Japanese Patent Publication No. 63-16325.

The modified polysilsesquiazane of the present invention has high stability and does not substantially polymerize during storage to increase the molecular weight. It was a completely unexpected finding that the stability of a polymer is improved by simply introducing a difunctional and / or monofunctional structural unit into a trifunctional basic structural unit. Without being bound by a particular theory, in the case of a polymer consisting only of trifunctional basic structural units, there are a large number of distorted ring structures in the molecule, which are cleaved upon storage and are cleaved. It is possible that the moiety recombines with other similarly cleaved molecules to increase molecular weight. When a bifunctional and / or monofunctional structural unit is introduced into a trifunctional basic structural unit, such a dissociated ring structure is reduced, so that such cleavage / recombination hardly occurs, and the polymer has a high molecular weight. It is thought that the conversion is suppressed.

By combining the modified polysilsesquiazane of the present invention with a photoacid generator, a photosensitive composition capable of finally forming a patterned ceramic film by exposure can be constituted. The photoacid generator is directly or by irradiation with light in its unique photosensitive wavelength range.
Further, when a sensitizing dye is used, the sensitizing dye is indirectly brought into an excited state by irradiation with light in a wavelength range in which the sensitizing dye is excited. The Si-N bond of the modified polysilsesquiazane poly is cleaved by the photoacid generator in an excited state, and the silanol (Si-OH) bond is formed by reacting with moisture in the atmosphere through a dangling bond state. It is considered to be generated. Since silanol is soluble in a developer described later, only the light-irradiated portion of the coating film of the photosensitive composition is dissolved and removed, and positive patterning is achieved.

[0014] The photoacid generator can be a peroxide. As specific examples of the peroxide-based photoacid generator, 3,
3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, t-butylperoxybenzoate, methyl ethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetylacetone peroxide, 1,1-bis (t- Hexylperoxy) 3,3,5-trimethylcyclohexane,
1-bis (t-hexylperoxy) cyclohexane,
1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, di-t-butylperoxy-
2-methylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) butane, n-butyl 4, 4-bis (t-butylperoxy) valerate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl)
Propane, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-
Tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-
Butyl hydroperoxide, α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-butylcumyl peroxide, -T-butyl peroxide, 2,5-dimethyl-
2,5-bis (t-butylperoxy) hexyne-3,
Isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide,
Lauroyl peroxide, stearoyl peroxide,
Succinic peroxide, m-toluoylbenzoyl peroxide, benzoyl peroxide, di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxyethylperoxydicarbonate , Di-2-ethylhexylperoxydicarbonate, di-3-methoxybutylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, α, α'-bis (neodecanylperoxy) diisopropylbenzene, Cumyl peroxy neodecanoate, 1,1,3
3-tetramethylbutyl peroxy neodecanoate,
1-cyclohexyl-1-methylethyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-butyl peroxy neodecanoate, t-hexyl peroxy pivalate, t-butyl peroxy pivalate, 1,1, 3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-
2,5-bis (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy 2-ethylhexanoate, t-butylperoxy 2-ethyl Hexanoate, t-butylperoxyisobutyrate, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid,
t-butylperoxy 3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-
Dimethyl-2,5- (m-toluoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy 2-ethylhexyl monocarbonate, t-hexylperoxybenzoate,
2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyacetate, t-
Butylperoxy-m-toluoylbenzoate, bis (t-butylperoxy) isophthalate, t-butylperoxyallylmonocarbonate, t-butyltrimethylsilyl peroxide, 2,3-dimethyl-2,3-
Diphenylbutane, 1,3-di (t-butylperoxycarbonyl) benzene, and the like.

[0015] The photoacid generator can also be a naphthoquinonediazidosulfonic acid ester or a nitrobenzyl ester. Specific examples of the naphthoquinonediazidesulfonic acid ester-based photoacid generator include 1,2-naphthoquinone-
(2) -diazide-5-sulfonic acid chloride, 1,2
-Naphthoquinone- (2) -diazido-4-sulfonic acid chloride, a mixture of 2,3,4-trihydroxybenzophenone and 6-diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid (mono to Tri) ester,
2,3,4,4'-trihydroxybenzophenone and 6
(Mono-tri) esters with -diazo-5,6-dihydro-5-oxo-naphthalene-1-sulfonic acid, and the like. Specific examples of the nitrobenzyl ester-based photoacid generator include nitrobenzyl tosylate, dinitrobenzyl tosylate, nitrobenzyl chloride, dinitrobenzyl chloride, nitrobenzyl bromide, dinitrobenzyl bromide, nitrobenzyl acetate, dinitrobenzyl acetate, nitrobenzyl Trichloroacetate, nitrobenzyl trifluoroacetate, and the like. Benzoin tosylate, nitrobenzyl sulfonic acids, onium salts [eg, bis (4-t-butylphenyl) iodonium salt and triphenylsulfonium salt] are also useful as other photoacid generators. If necessary, these photoacid generators can be used in combination.

The photosensitive composition according to the present invention generally contains the above-mentioned photoacid generator in an amount of 0.05 to 50% by mass based on the mass of the modified polysilsesquiazane, depending on the type and use. If the content of the photoacid generator is less than 0.05% by mass, the decomposition reaction rate becomes extremely slow, and
When the content is more than the mass%, it becomes difficult to obtain a dense film characteristic of the modified polysilsesquiazane. The photoacid generator is
It is preferably contained in an amount of 0.1 to 20% by mass, more preferably 1 to 20% by mass, based on the mass of the modified polysilsesquiazane.

The preparation of the photosensitive composition according to the present invention is carried out by adding the above-mentioned photoacid generator to modified polysilsesquiazane. It is preferable to uniformly mix the photoacid generator. For this purpose, the modified polysilsesquiazane and the photoacid generator are mixed with sufficient stirring, or each is dissolved in a solvent described below and diluted before mixing. It is desirable to do. In particular, when the photoacid generator is a solid at the time of mixing, it is preferable to dissolve this in a solvent before mixing. The temperature and pressure at the time of addition are not particularly limited, and the addition can be performed at room temperature and under atmospheric pressure. However, in order not to excite the photoacid generator, it is desirable to work in an environment not containing the photosensitive wavelength of the photoacid generator to be used, preferably in a dark place, from the time of its addition to the development step described below. .

When the photosensitive composition containing the modified polysilsesquiazane obtained and the photoacid generator must be stored for a certain period of time or more, some photoacids such as nitrobenzyl sulfonic acid ester may be used. For the generator, a small amount of NH released from the modified polysilsesquiazane during storage
It may be decomposed by ₃ . In such a case, the storage stability of the photosensitive composition is improved by selecting a base-resistant photoacid generator. Such base-resistant photoacid generators include iminosulfonate derivatives, disulfone derivatives, diazomethane derivatives, 4-methoxy-α
Examples include sulfoxime-based compounds such as-((((4-methoxyphenyl) sulfonyl) oxy) imino) benzeneacetonitrile and triazine-based compounds such as the following compounds.

[0019]

Embedded image

It may be advantageous to mix a sensitizing dye with the photosensitive composition according to the invention. Some photoacid generators, such as 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, have a wavelength range in which themselves are excited to be shorter than about 330 nm. Light irradiation was performed using a KrF system (248 nm) or an ArF system (193n).
m), etc., when using an excimer laser,
No sensitizing dye is needed because the photoacid generator is directly excited. However, high pressure mercury lamp (360-430nm)
When an inexpensive light source such as the above is used, the photoacid generator can be indirectly excited by combining a sensitizing dye excited in the wavelength region. Thus, by combining a sensitizing dye, the photosensitive composition of the present invention can be patterned using a commonly used inexpensive light source.

Examples of sensitizing dyes that can be used in the photosensitive composition of the present invention include coumarin, ketocoumarin and derivatives thereof, thiopyrylium salts, and the like.
Bis (o-methylstyryl) benzene, 7-dimethylamino-4-methylquinolone-2, 7-amino-4-methylcoumarin, 4,6-dimethyl-7-ethylaminocoumarin, 2- (p-dimethylaminostyryl) ) -Pyridylmethyl iodide, 7-diethylaminocoumarin, 7-diethylamino-4-methylcoumarin, 2,3,5,6-
1H, 4H-tetrahydro-8-methylquinolizino- <
9,9a, 1-gh> coumarin, 7-diethylamino-
4-trifluoromethylcoumarin, 7-dimethylamino-4-trifluoromethylcoumarin, 7-amino-4-
Trifluoromethyl coumarin, 2,3,5,6-1H,
4H-tetrahydroquinolizino- <9,9a, 1-gh
> Coumarin, 7-ethylamino-6-methyl-4-trifluoromethylcoumarin, 7-ethylamino-4-trifluoromethylcoumarin, 2,3,5,6-1H, 4H
-Tetrahydro-9-carbethoxyquinolizino- <
9,9a, 1-gh> coumarin, 3- (2′-N-methylbenzimidazolyl) -7-N, N-diethylaminocoumarin, N-methyl-4-trifluoromethylpiperidino- <3,2- g> coumarin, 2- (p-dimethylaminostyryl) -benzothiazolylethyl iodide, 3
-(2'-benzimidazolyl) -7-N, N-diethylaminocoumarin, 3- (2'-benzothiazolyl)-
7-N, N-diethylaminocoumarin, and pyrylium salts and thiopyrylium salts represented by the following formula.

[0022]

Embedded image

Further specific examples of the sensitizing dye include the following compounds.

[0024]

Embedded image

Particularly preferred sensitizing dyes are 7-diethylamino-4-methylcoumarin and 7-diethylamino-4-methylcoumarin.
It is trifluoromethyl coumarin. When sensitizing dyes are combined, the sensitizing dyes are generally present in the photosensitive composition according to the invention in an amount of from 0.05 to 50% by weight, preferably from 1 to 20% by weight, based on the weight of the modified polysilsesquiazane. What is necessary is just to make it contain.

When a sensitizing dye is mixed with the photosensitive composition according to the present invention, the resulting coating may be colored.
When using the composition as a photoresist,
Since the resist is removed after the desired patterning process is completed, coloring of the resist hardly causes a problem. However, when a film containing a sensitizing dye is used without being removed after patterning, for example, when a patterned interlayer insulating film is produced using the photosensitive composition of the present invention, the film after baking is exposed to visible light. It may be necessary to be transparent to Even in such a case, the photoacid generator contained in the photosensitive composition of the present invention can decompose the sensitizing dye at the time of film baking to make the film transparent. Further, a transparent film can be obtained by separately adding an oxidation catalyst which does not directly participate in the photoreaction but decomposes the sensitizing dye at the time of film baking to the photosensitive composition of the present invention. Examples of such oxidation catalysts include metal organic compounds and fine particles such as palladium propionate, palladium acetate, platinum acetylacetonate, platinum ethylethylacetonate, fine palladium particles, and fine platinum particles. When an oxidation catalyst is added, it is contained in the photosensitive composition of the present invention in an amount of generally 0.05 to 10% by mass, preferably 0.1 to 5% by mass based on the mass of the modified polysilsesquiazane. Good. In addition, by adding such an oxidation catalyst, unnecessary dyes are decomposed and decolored, and the conversion of the modified polysilsesquiazane into a ceramic can be promoted.

As another embodiment of the present invention, by adding a pigment to the above-mentioned photosensitive composition, a photosensitive material which is excellent in heat resistance, insulation and hardness, and which is suitable for producing a color filter and a black matrix having good pattern accuracy is provided. Composition can be obtained. The color filter and the black matrix obtained from the photosensitive composition containing the pigment according to the present invention have excellent heat resistance (oxidation resistance at high temperatures) because the pigment is dispersed in the silica-based ceramics, so that oxygen is blocked. At the same time, even if the pigment itself is conductive, it becomes an insulator as a color filter or a black matrix. In addition, since the silica-based ceramic film has higher hardness than general organic films such as acrylic and polyimide, the workability (film deposition, wiring, bonding work) on the surface of the color filter or black matrix is improved, The yield can be increased. Further, the amount of outgas generated from the ceramic film at the time of heating is much smaller than the amount of outgas generated from a general organic film.

Examples of pigments that can be added to the photosensitive composition of the present invention include graphite, carbon black, titanium black, iron oxide, copper chromium black, copper iron manganese black, cobalt iron chromium black,
And the like. The amount of the pigment added is generally 0.05 to 1000% by mass, preferably 10 to 100% by mass based on the mass of polysilazane.
~ 500% by mass. When a pigment is used, the photosensitive composition to which the pigment according to the present invention is added is prepared by adding the photoacid generator and / or the sensitizing dye and / or the oxidation catalyst and the pigment to the modified polysilsesquiazane. This is done by: The order of addition is not critical, but it is preferable to mix the two uniformly. For this purpose, mixing is performed with sufficient stirring during the addition, and the photoacid generator and / or
Alternatively, it is desirable to dissolve or disperse the sensitizing dye and / or the oxidation catalyst in a solvent described below and dilute the mixture before mixing.

When a solvent is used, benzene, toluene, xylene, ethylbenzene, diethylbenzene,
Aromatic compounds such as trimethylbenzene and triethylbenzene; cyclohexane; cyclohexene; decahydronaphthalene; dipentene; n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-
Heptane, n-octane, i-octane, n-nonane,
saturated hydrocarbon compounds such as i-nonane, n-decane and i-decane; ethylcyclohexane; methylcyclohexane; p-menthane; ethers such as dipropyl ether and dibutyl ether; methyl isobutyl ketone (MI
It is preferable to use ketones such as BK); esters such as butyl acetate, cyclohexyl acetate, and butyl stearate. When using these solvents, in order to adjust the solubility of polysilazane and the evaporation rate of the solvent,
Two or more solvents may be mixed.

The amount (proportion) of the solvent used is selected so that the workability is improved by the coating method to be used, and it depends on the average molecular weight, molecular weight distribution and structure of the modified polysilsesquiazane used. Can be mixed. However, in consideration of the stability and production efficiency of the modified polysilsesquiazane, the concentration of the modified polysilsesquiazane is preferably 0.1 to 50% by mass, more preferably 0.1 to 40% by mass.

Further, a suitable filler and / or extender can be added to the photosensitive composition according to the present invention, if necessary. Examples of the filler include fine powders of oxide-based inorganic substances such as silica, alumina, zirconia, and mica, and non-oxide-based inorganic substances such as silicon carbide and silicon nitride. Depending on the application, metal powder such as aluminum, zinc, and copper can be added. These fillers may be of various shapes such as needles (including whiskers), granules, and scales, or may be used alone or in combination of two or more.
Further, it is desirable that the size of the particles of these fillers is smaller than the film thickness that can be applied at one time. The addition amount of the filler is in the range of 0.05 to 10 parts by mass, particularly preferably 0.2 to 3 parts by mass, based on 1 part by mass of the modified polysilsesquiazane. . The photosensitive composition of the present invention, if necessary, various pigments, leveling agents, defoamers, antistatic agents, ultraviolet absorbers, pH adjusters, dispersants,
A surface modifier, a plasticizer, a drying accelerator, and a flow stopper may be added.

According to the present invention, there is also provided a method for forming a patterned silica-based ceramic film using the above photosensitive composition. That is, the method of the present invention comprises the steps of: forming a coating film of a photosensitive composition containing a modified polysilsesquiazane and a photoacid generator; irradiating the coating film with light in a pattern; Dissolving and removing the irradiated portion of the film.

The coating of the photosensitive composition according to the present invention is formed by a general coating method, such as dipping, roll coating, bar coating, brush coating, spray coating, flow coating, spin coating and the like. Silicon substrate, glass substrate,
Etc. on a suitable substrate. When the substrate is a film, gravure coating is also possible. If desired, a drying step of the coating film can be separately provided. The coating film can be formed to a desired thickness by repeating the application once or twice or more as necessary. The desired film thickness varies depending on the application. For example, in the case of a photoresist, 0.05 to 2 μm, and in the case of an interlayer insulating film,
μm, 0.3 to 3 μm in the case of a color filter or a black matrix, and the like.

After the coating of the photosensitive composition of the present invention is formed, it is preferable to pre-bake (heat-treat) the coating in order to dry the coating and reduce the amount of degassing thereafter. The pre-bake step is generally performed at a temperature of 40 to 200 ° C., preferably 60 to 120 ° C., for 10 to 180 seconds, preferably 30 to 90 seconds when using a hot plate, and 1 to 30 minutes when using a clean oven. Can be carried out for 5 to 15 minutes.

After a coating film of the photosensitive composition of the present invention is formed and, if necessary, prebaked, the coating film is irradiated with light in a pattern. As such a light source, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, an excimer laser, or the like can be used. It is common to use light (high-pressure mercury lamp) of 360 to 430 nm as the irradiation light except for ultrafine processing such as a semiconductor. Above all, in the case of a liquid crystal display device, light of 430 nm is often used. As described above, in such a case, it is advantageous to combine a sensitizing dye with the photosensitive composition of the present invention. The energy of the irradiation light depending on the light source and the desired thickness, generally 5~4000mj / cm ^2, preferably between 10 to 2000 mJ / cm ^2. If this energy is lower than 5 mj / cm ² , the modified polysilsesquiazane will not be sufficiently decomposed, and if it is higher than 4000 mj / cm ² , excessive exposure may occur, resulting in the occurrence of halation.

A general photomask may be used to irradiate in a pattern, and such a photomask is well known to those skilled in the art. In general, the environment for the irradiation may be an ambient atmosphere (in the air) or a nitrogen atmosphere, but an atmosphere having an increased oxygen content may be employed in order to promote the decomposition of the modified polysilsesquiazane.

In the exposed portion of the photosensitive composition which has been irradiated in a pattern, the Si—N bond of the modified polysilsesquiazane is cleaved and reacts with the moisture in the atmosphere via a dangling bond. Silanol (Si-O
H) A bond is formed and the modified polysilsesquiazane is decomposed. In order to promote the formation of the silanol bond, water, preferably pure water, may be brought into contact with the modified polysilsesquiazane composition after exposure. By developing the coating film after irradiation, the exposed portion of the photosensitive composition is removed, and the unexposed portion remains on the substrate to form a pattern (positive type). Since the remaining modified polysilsesquiazane hardly swells in the developing solution described later, the pattern of the irradiation light and the pattern of the modified polysilsesquiazane to be decomposed and removed almost completely match, and good pattern accuracy (resolution) is obtained. can get.

At the time of removing the exposed portion of the photosensitive modified polysilsesquiazane composition, that is, at the time of development, an aqueous alkali solution can be used as a developer. Examples of such an alkaline aqueous solution include aqueous solutions of tetramethylammonium hydroxide (TMAH), sodium silicate, sodium hydroxide, potassium hydroxide, and the like. In the development in the present invention, it is convenient to use an approximately 2% aqueous TMAH solution which is an industry standard alkaline developer. Although the time required for development depends on the film thickness and the solvent, it is generally 0.1 time.
-5 minutes, preferably 0.5-3 minutes. The development temperature is generally 20 to 50 ° C, preferably 20 to 30 ° C.
° C.

In order to enhance the development efficiency, compounds known in the art as so-called dissolution inhibitors can be added to the photosensitive composition of the present invention. A general dissolution inhibitor prevents the polymer from being eluted in an alkali developer in an unexposed portion of the coating film due to its hydrophobicity.
In the exposed portion, the dissolution inhibitor itself is decomposed by exposure or by the photoacid generator to become hydrophilic, thereby having an action of accelerating the decomposition of the polymer. As mentioned above,
Since the modified polysilsesquiazane according to the present invention does not dissolve in the developing solution, it hardly enjoys the merit of preventing the dissolution inhibitor from dissolving the unexposed portion, but the dissolution promoting effect of the exposed portion works advantageously. I understood. That is, by adding a so-called dissolution inhibitor to the photosensitive composition of the present invention, the development efficiency can be improved in that the dissolution rate of the exposed portion is increased. Specific examples of such a dissolution inhibitor include catechol t-butoxycarbonyl (hereinafter, t-BOC), hydroquinone t-BOC, benzophenone-4,4′-dicarboxylic acid t-butyl ester, and 4,4′-. Oxydibenzoic acid t-
Butyl ester, and the like. The dissolution inhibitor is used in an amount of 0.1 to 40% by mass, preferably 1 to 40% by mass based on the photosensitive composition.
It can be added in the range of 30% by mass.

By the development, the exposed portions of the photosensitive modified polysilsesquiazane composition are removed, and the patterning is completed. The patterned modified polysilsesquiazane film can be directly used as a photoresist having high chemical resistance. Since the photoresist according to the present invention is a positive type, it has high resolution and high dry etching resistance. In particular, since the photoresist according to the present invention has high oxygen plasma resistance, it is very useful as a substitute for a silicon-containing resist in a two-layer resist method. After the lower layer or the substrate is etched using the photoresist according to the present invention as a protective film, the used photoresist is removed. The photoresist of the present invention can be removed by dissolving and removing the modified polysilsesquiazane using the above-mentioned solvent.

When the modified polysilsesquiazane film patterned according to the present invention is used while remaining as an interlayer insulating film or the like, by leaving it for a long time or sintering, high heat resistance, low dielectric constant, and transparency are obtained. What is necessary is just to convert it into a silica-based ceramics coating excellent in, for example,. When the modified polysilsesquiazane film after development is allowed to stand, it is generally sufficient to leave it in an ambient atmosphere (in the air, at room temperature) for a long time, for example, one day or more. In the case of firing, the firing temperature depends on the type of the modified polysilsesquiazane used and the heat resistance of the substrate, the electronic component, and the like.
Preferably 100-1000 ° C, more preferably 150
C to 450C. The firing time is generally 5 minutes or more, preferably 10 minutes or more. In general, the firing atmosphere may be an ambient atmosphere (in the air), but an atmosphere having an increased oxygen content and / or a partial pressure of water vapor may be employed to promote the oxidation of the modified polysilsesquiazane. The silica-based ceramic coating thus obtained has a dielectric constant of 5
Hereinafter, in some cases, the dielectric constant is 3.3 or less, and the resistivity is 10 ¹³
Ωcm or more.

[0042]

The following examples further illustrate the present invention. Example 1 Preparation of Modified Polysilsesquiazane A four-necked flask was equipped with a gas blowing tube, a mechanical stirrer, and a dewar condenser. After the inside of the reactor was replaced with deoxygenated dry nitrogen, the raw materials CH ₃ SiCl ₃ and (CH ₃ ) ₂ SiCl ₂ and / or (CH ₃ ) ₃ SiCl were mixed in a four-neck flask at a predetermined molar ratio. (Total of about 50 g), and further, degassed dry pyridine was added so that the raw material concentration became about 10% by mass, and the mixture was cooled with ice.
With stirring, ammonia (NH ₃ ) was mixed with nitrogen gas and blown into the raw material mixture until the reaction was completed. After completion of the reaction, the solid product was centrifuged and further filtered off. Removal of the solvent from the filtrate under reduced pressure gave a modified polysilsesquiazane. In the modified polysilsesquioxane sesqui Azan - [Si (CH _{3) 2} NH] - and [Si (C
The composition ratio of H ₃ ) ₃ (NH) _0.5 ]-is determined by Si-NMR.
It can be measured by spectrum. The configuration of the modified polysilsesquiazane can be generally known from characteristic peaks due to various bonds in an infrared (IR) absorption spectrum. For example, as another structural unit,-[Si
FIG. 1 shows the IR spectrum of a modified polysilsesquiazane containing (CH ₃ ) ₂ NH] — in an amount of 20 mol%. From these measurement results, it was confirmed that the ratio of the various constituent units in the modified polysilsesquiazane according to the present invention almost reflected the molar ratio of the corresponding starting material.

Example 2 Storage Stability of Polymer The storage stability of the modified polysilsesquiazane was evaluated as follows. According to the procedure described in Example 1,-[S
iCH ₃ (NH) _1.5 ]-as a basic structural unit, and-[S
i (CH _{3) 2} NH] - or [Si (CH _{3) 3} (N
H) A modified polysilsesquiazane containing another structural unit represented by _0.5 ]-at a ratio shown in Table 1 below with respect to the basic structural unit, and a polysilsesquiazane consisting only of the basic structural unit are prepared. Each was dissolved in propylene glycol monomethyl ether acetate (PGMEA) and dissolved in 20
% Solution. Put each solution in a closed container,
For one week. The number average molecular weight and the weight average molecular weight of each polymer before and after storage were measured by gel permeation chromatography (GPC).

[0044]

[Table 1]

Polysilsesquiazane consisting of only the basic structural unit-[SiCH ₃ (NH) _1.5 ]-has a substantially increased molecular weight during one week of storage (Comparative Example). However, as other structural units - [Si (CH _{3) 2} NH] -
Or _{[Si (CH 3) 3 (NH} ) 0.5 ] - in the case of the modified polysilsesquioxane sesqui Azan containing (present invention), molecular weight due to storage for a week was observed little or no.

Example 3 Influence of Photoacid Generator on Storage Stability of Photosensitive Composition According to the procedure described in Example 1,-[SiCH ₃ (N
H) _1.5] - was used as a basic unit, - [Si (CH _3)
2 NH] - was prepared modified polysilsesquioxane sesqui Azan containing about 10 mole%. To this modified polysilsesquiazane, 5% by mass of a nitrobenzylsulfonic acid ester represented by the following formula (1) or a triazine derivative represented by the following formula (2) is added as a photoacid generator, and a sensitizer of the formula (3) Was added in an amount of 5% by mass. Finally, the photosensitive composition was prepared by diluting with isoamyl acetate so that the polymer concentration became 10% by mass.

[0047]

Embedded image

The i-line sensitivity of each photosensitive composition immediately after preparation was
Each photosensitive composition is spin-coated on a silicon wafer to form a coating film, and then exposed (360 nm) and developed (T
MAH: 2.38% aqueous solution of tetramethylammonium hydroxy). On the other hand, each photosensitive composition was placed in a closed container and stored at a constant temperature of 50 ° C. for one week. The i-ray sensitivity of each photosensitive composition after storage was measured in the same manner. The measurement results are shown in the following table.

[0049]

[Table 2]

The i-ray sensitivity of the photosensitive composition using nitrobenzylsulfonic acid ester as a photoacid generator was reduced to 1/10 after storage for one week. On the other hand, the i-line sensitivity of the photosensitive composition using the triazine derivative hardly changed before and after storage. As described above, the photosensitive composition containing the modified polysilsesquiazane has a difference in storage stability depending on the type of the photoacid generator. As a cause, a small amount of ammonia released from the modified polysilsesquiazane during storage is generated. ,
Decomposing some photoacid generators, including nitrobenzyl sulfonic acid esters. Therefore, the storage stability of the photosensitive composition of the present invention can be improved by using such a base-resistant photoacid generator that is not decomposed by a base.

Example 4 : Improvement of development efficiency According to the procedure described in Example 1,-[SiCH ₃ (N
H) _1.5 ]-as a basic structural unit, and [Si (CH ₃ ) ₃
A modified polysilsesquiazane containing (NH) _0.5 ]-at about 2.5 mol% was prepared. This modified polysilsesquiazane was dissolved in propylene glycol monomethyl ether acetate (PGMEA) to obtain a 20% by mass solution.
To this solution, 2% by mass of a triazine derivative represented by the formula (4) was added as a photoacid generator. This solution was divided into two, and benzophenone-4,4'-dicarboxylic acid t-butyl ester represented by the formula (5) as a dissolution inhibitor was added to one of the solutions at 2% by mass relative to the polymer mass.

[0052]

Embedded image

Each solution was spin coated on a silicon wafer to form a coating and prebaked at 90 ° C. for 90 seconds. T before and after i-ray exposure of 40 mJ
The dissolution rate in the MAH aqueous solution (developer) was measured. The measurement results are shown in the following table.

[0054]

[Table 3]

Since the modified polysilsesquiazane was insoluble in the TMAH developer, the dissolution rate was 0 before i-line exposure regardless of the presence or absence of the dissolution inhibitor. However, after i-line exposure, the dissolution rate was doubled by the addition of the dissolution inhibitor, and it was confirmed that the development efficiency was improved by adding the dissolution inhibitor to the photosensitive composition of the present invention.

[0056]

According to the present invention, the stability of the polymer itself is improved by introducing a specific amount of a specific structural unit into the basic structural unit of polysilsesquiazane. Further, by selecting a photoacid generator having basic resistance, the storage stability of the photosensitive composition containing polysilsesquiazane is improved. Further, by adding a compound known as a dissolution inhibitor, the development efficiency of the photosensitive composition is increased. The modified polysilsesquiazane film according to the present invention has a high oxygen plasma resistance, so that it is very useful as a substitute for a silicon-containing resist in a two-layer resist method, and the modified polysilsesquiazane patterned according to the present invention. By leaving or baking the film for a long time, a patterned silica-based ceramic film excellent in high heat resistance, low dielectric constant, transparency, etc. suitable as an interlayer insulating film can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing an infrared absorption spectrum of a modified polysilsesquiazane according to the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/039 G03F 7/039 7/075 511 7/075 511 H01L 21/027 H01L 21/312 C 21 / 312 21/30 502R F-term (Reference) 2H025 AA04 AA11 AA13 AA20 AB16 AB17 AC01 AD03 BE00 BE08 BF30 CB32 FA29 4J002 CP21W EU186 EV246 FD206 GP03 4J035 HA03 LB16 5F058 AA10 AC03 AD05 AF04 AG01 AH02 AH03 AH10

Claims (3)

[Claims] 1. The general formula:-[SiR ¹ (NR ² ) _1.5 ]
- was the basic unit, further general formula: - [SiR ¹ ₂
NR ^2] - and / or [SiR ¹ ₃ (NR ²⁾ _0.5] -
A number average molecular weight of 10 containing from 0.1 mol% to 100 mol% of other structural units represented by the formula:
0-100,000 modified polysilsesquiazane. (Wherein, R ¹ each independently represents an alkyl group having 1 to 3 carbon atoms or a substituted or unsubstituted phenyl group, and R ² each independently represents hydrogen, an alkyl group having 1 to 3 carbon atoms or a substituted phenyl group. Or represents an unsubstituted phenyl group.) 2. A photosensitive composition comprising the modified polysilsesquiazane according to claim 1 and a photoacid generator selected from the group consisting of a sulfoxime compound and a triazine compound. 3. A step of forming a coating film of the photosensitive composition according to claim 2, a step of irradiating the coating film with light in a pattern, and dissolving and removing an irradiated portion of the coating film. Forming a patterned modified polysilsesquiazane film comprising the steps of: