JPH0456068B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a photosensitive polyimide coating agent composition, and more particularly to an improvement of a photosensitive polyimide composition containing silica. [Prior Art] Photosensitive polyimide compositions include compositions in which a compound containing a carbon-carbon double bond and an amino group or a quaternized salt thereof that can be dimerized or polymerized by actinic radiation is added to polyamic acid (for example, Special Public Service 1984-
52822) is known. Furthermore, compositions in which fine silica powder (white carbon) is added to polyamic acid, which is a polyimide precursor, are known (for example, JP-A-54-121673
Publication No.). When a composition prepared by adding the above-mentioned white carbon to photosensitive polyimide is observed under a microscope, many coarse secondary aggregates are seen. Due to the presence of these coarse secondary aggregates, when trying to form a coating film using a spinner or other methods, pinholes, abnormal protrusions, etc. occur, making it difficult to form a uniform film and making it impossible to obtain a good pattern. There was a problem. [Problems to be Solved by the Invention] The present invention solves the above-mentioned drawbacks, that is, it eliminates coarse secondary aggregates, can form a uniform coating film without pinholes or abnormal protrusions, and has a photosensitive function. The object of the present invention is to provide a novel photosensitive polyimide composition containing the following. [Means for solving the problems] The present invention has the following features: (1) (a) General formula (However, in the formula, R ₁ is a trivalent or tetravalent organic group,
R ₂ is a divalent organic group, and m is 1 or 2. ); (b) a compound [] containing a photosensitive group and an aliphatic tertiary amino group; and (c) an organosilica sol []; Photosensitivity characterized in that the amount S (wt%) added of the organosilica sol [] given by wt%) = SiO ₂ (g) / SiO ₂ + amount of polyamic acid (g) x 100 is 2 to 40 wt%. It is a polyimide composition. In the present invention, the polyamic acid having the structural unit [ ] has a structure represented by the general formula,
By heating or using a suitable catalyst, it can be turned into a polymer having an imide ring or other cyclic structure (hereinafter referred to as a polyimide polymer). In the above structural unit [ ], R ₁ is a trivalent or tetravalent organic group having at least two or more carbon atoms. In terms of heat resistance of polyimide polymers,
Preferably, R ₁ has a structure in which the bond to the carbonyl group of the polymer main chain is directly formed through an aromatic ring or an aromatic heterocycle. Therefore, R ₁ is preferably a trivalent or tetravalent group containing an aromatic ring or an aromatic heterocycle and having 6 to 30 carbon atoms. As a more preferable specific example of R ₁ ,

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(In the formula, the bond represents a bond with the carbonyl group of the polymer main chain, and the carboxyl group is located at the ortho position to the bond, but this bond is not shown in the above structural formula). Examples include, but are not limited to, the following. Further, in the polymer having the structural unit [ ], R ₁ may be composed of only one type among these, or may be a copolymer composed of two or more types. Particularly desirable R ₁ is

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[Formula] (However, the definition of the bond in the formula is the same as above). In the above structural unit [ ], R ₂ is a divalent organic group having at least 2 or more carbon atoms,
In terms of heat resistance when used as a polyimide polymer,
It is preferable that the polymer has a structure in which the bond to the amide group in the main chain of the polymer is made directly from an aromatic ring or an aromatic heterocycle. Therefore, R ₂ is preferably a divalent group containing an aromatic ring or an aromatic heterocycle and having 6 to 30 carbon atoms. Preferred specific examples of R ₂ include:

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(In the formula, the bond represents a bond with an amide group in the main chain). Furthermore, these may have substituents such as amino groups, amide groups, carboxyl groups, and sulfonamide groups within the range that does not adversely affect the heat resistance of the polyimide polymer. Among those having each of these substituents, particularly preferred examples include: can be mentioned. In the polymer having the structural unit [ ], R ₂ may be composed of only one of these,
It may be a copolymer composed of two or more types. Furthermore, in order to improve the adhesiveness of the polyimide polymer, it is also possible to copolymerize an aliphatic group having a siloxane structure as R ₂ within a range that does not reduce the heat resistance. As a preferred example Examples include. Specific examples of polymers containing the structural unit [
4′-Benzophenonetetracarboxylic acid and 4,4′-
Diaminodiphenyl ether, 3,3',4,4'-benzophenonetetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride and 4,4'-diaminodiphenyl ether, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride anhydride and 4,4'-diaminodiphenyl ether, pyromellitic dianhydride and 3,3'-diaminodiphenyl sulfone, pyromellitic dianhydride and 3,3',4,
4'-Benzophenonetetracarboxylic dianhydride and 3,3'-(or 4,4'-)diaminodiphenylsulfone, 3,3',4,4'-benzophenonetetracarboxylic dianhydride and 3,3'-(or 4,4'-)diaminodiphenylsulfone, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 3,3'-(or 4,4'-) ) Diaminodiphenylsulfone, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride and 3,3'- (or 4,
4′-)diaminodiphenyl sulfone, pyromellitic dianhydride and 4,4′-diaminodiphenyl ether, and bis(3-aminopropyl)tetramethyldisiloxane, pyromellitic dianhydride and 3,3′,4 ，
4'-Benzophenonetetracarboxylic dianhydride, 4,4'-diaminodiphenyl ether and bis(3-aminopropyl)tetramethyldisiloxane, 3,3',4,4'-benzophenonetetracarboxylic acid Acid dianhydride and 4,4'-diaminodiphenyl ether and bis(3-aminopropyl)tetramethyldisiloxane, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 4,4' -diaminodiphenyl ether and bis(3-aminopropyl)tetramethyldisiloxane, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 3,3',4,4'-benzophenone Tetracarboxylic dianhydride and 4,4'-diaminodiphenyl ether and bis(3-aminopropyl)tetramethyldisiloxane, pyromellitic dianhydride and 3,3'-(or 4,
4′-)diaminodiphenyl sulfone and bis(3-aminopropyl)tetramethyldisiloxane, pyromellitic dianhydride and 3,3′,4,
4'-Benzophenonetetracarboxylic dianhydride, 3,3'-(or 4,4'-)diaminodiphenylsulfone and bis(3-aminopropyl)tetramethyldisiloxane, 3,3',4, 4'-Benzophenonetetracarboxylic dianhydride, 3,3'-(or 4,4'-)diaminodiphenylsulfone and bis(3-aminopropyl)tetramethyldisiloxane, 3,3',4, 4'-biphenyltetracarboxylic dianhydride, 3,3'-(or 4,4'-)diaminodiphenylsulfone and bis(3-aminopropyl)tetramethyldisiloxane, 3,3',4,4 '-biphenyltetracarboxylic dianhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride and 3,3'-(or 4,
Polyamic acids synthesized from 4'-)diaminodiphenyl sulfone and bis(3-aminopropyl)tetramethyldisiloxane are preferably used. The polymer having the structural unit [] as a main component may be composed only of the structural unit [], or may be a copolymer with other structural units.
The type and amount of structural units used in the copolymerization are desirably selected within a range that does not significantly impair the heat resistance of the polyimide polymer obtained by the final heat treatment. Typical examples include structural units of polyamideamic acid and polyesteramic acid, but are not limited thereto. The compound [] containing a photosensitive group and an aliphatic tertiary amino group in the present invention is a compound containing a carbon-carbon double bond or a photosensitive group such as an azide group and an aliphatic tertiary amino group in one molecule. be. The following general formula [A] (Here, R ₃ is hydrogen or a phenyl group, R ₄ is hydrogen or a lower alkyl group having 1 to 6 carbon atoms, R ₅ is a substituted or unsubstituted hydrocarbon group having 2 to 12 carbon atoms, R ₆ ,
R ₇ represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms), and general formula [B] (Here, R ₈ represents hydrogen, a lower alkyl group having 1 to 6 carbon atoms, or a vinyl group, and R ₉ represents hydrogen or a methyl group), and the general formula [C], [D] or (Here, R ₁₀ and R ₁₁ are hydrogen or have 1 to 6 carbon atoms.
R ₁₂ and R ₁₃ are hydrogen or a lower alkyl group having 1 to 6 carbon atoms, R ₁₄ is an alkylene group having 1 to 12 carbon atoms, and R ₁₅ and R ₁₆ are hydrogen or lower alkyl groups having 1 to 6 carbon atoms. lower alkyl group, n is 1 to 3)
and general formula [E] _{( where , _ _ _ _} ) is preferably used. As a preferred specific example, (CH ₂ = CHCH ₂ ) ₃ N (-5) Examples include, but are not limited to, the following. Compounds having a methacrylic group as a photosensitive group are particularly preferably used from the viewpoint of both photosensitive performance and raw material cost. These compounds may be used alone or as a mixture of two or more. In addition, primary amines, secondary amines, and vinylpyridine having photosensitive groups, or primary amines, secondary amines, and Organic basic compounds such as primary amines and tertiary amines may be added. The amount of compound [] to be added is preferably 0.3 to 4.0 equivalents, more preferably 0.5 to 3.0 equivalents, based on the carboxyl group of the polyamic acid. If less than the lower limit amount is added, both photosensitive performance and the effect of eliminating coarse secondary aggregates will not be sufficiently observed, and if more than the upper limit amount is added, viscosity stability during storage will be poor. Become. In the present invention, colloidal silica [ ] is
It is a colloidal solution of high molecular weight silicic anhydride. This one
An example is a silica sol that is commercially available, and the dispersion medium is usually water, but silica sol that is dispersed in an organic solvent is also commercially available (for example, OSCAL manufactured by Catalysts & Chemicals Co., Ltd.). Silica sol dispersed in an organic solvent is prepared by replacing water, which is a dispersion medium of an aqueous silica sol, with an organic solvent. Replacement of the dispersion medium can be carried out by adding an organic solvent to the aqueous silica sol and distilling off the water. Depending on the type of solvent, a lower alcohol may be added to partially esterify the surface of the silica particles. From the viewpoint of compatibility with polyamic acid, organosilica sol dispersed in an organic solvent is desirable. In particular, dimethylformamide, which is a solvent for polyamic acid,
An organosilica sol dispersed in an aprotic polar solvent such as dimethylacetamide or N-2-pyrrolidone is preferred. Further, other colloidal silica that can be used in the present invention includes colloidal silica synthesized from alkyl silicate, and in this case, the effect of improving insulation and preventing corrosion of wiring can be expected. Here, alkyl silicate refers to the general formula Si
It is represented by (OR) ₄ (wherein R is a hydrocarbon having 1 to 15 carbon atoms). If R has a large number of carbon atoms, the amount of silica produced will decrease, so R is more preferably a hydrocarbon having 1 to 3 carbon atoms. Furthermore, from the viewpoint of safety for the human body, tetraethyl silicate represented by Si(OCH ₂ CH ₃ ) ₄ is particularly preferable as the alkyl silicate. Colloidal silica synthesized from alkyl silicate used in the present invention is produced by hydrolysis condensation of alkyl silicate, for example, by adding a mixture of methanol and aqueous ammonia to
It is obtained by adding tetraethyl silicate, performing hydrolytic condensation, then adding a suitable dispersion medium and distilling off methanol and ammonia. Regarding the temperature conditions during distillation, it is preferable to carry out the distillation at a low temperature, for example, at a temperature of 60° C. or lower, in order to prevent agglomeration of colloidal silica. As the dispersion medium, it is preferable to use an organic solvent from the viewpoint of compatibility with polyamic acid. Suitable organic solvents include dimethylacetamide, dimethylformamide, N-
Examples include aprotic polar solvents such as methyl-2-pyrrolidone, and it is particularly preferred to use N-methyl-2-pyrrolidone. The concentration of colloidal silica synthesized from alkyl silicate can be adjusted by the amount of dispersion medium added, but the concentration is preferably in the range of 5 to 30 wt% from the viewpoint of ease of mixing with varnish.
It is not limited to this. The amount S (wt%) of colloidal silica added is 0.5 to 50
(wt%), more preferably 2 to 40
(wt%) is good. Note that the amount S (wt%) of colloidal silica added is given by the following formula. S (wt%) = SiO ₂ amount (g) / SiO ₂ amount (g) +
Amount of polyamic acid (g) x 100 If less than the lower limit amount is added, the effect of improving the properties will not be significant, and if it is added in excess of the upper limit amount, the photosensitive performance will deteriorate. Further, when a sensitizer is used in combination with the composition of the present invention, the sensitivity is significantly improved and the exposure time is shortened, resulting in practical advantages. Preferred sensitizers include, for example, Michler's ketone, 4,4'-bis(diethylamino)benzophenone, dibenzalacetone,

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aromatic monoazide compounds such as, and (2,6-bis-(4'-azidobenzal)-cyclohexanone), Examples include, but are not limited to. These sensitizers may be used alone or as a mixture of two or more. Next, an example of a method for producing the composition of the present invention will be explained. First, a diamine compound and an acid dianhydride are reacted in a solvent to obtain a polymer whose main component is the structural unit [], and then this solution is added with the compound [], colloidal silica [], and if necessary, a sensitizer. It can be manufactured by dissolving and blending and other additives. Colloidal silica is sufficiently uniformly dispersed in the composition by ordinary stirring, but if necessary, methods such as high-speed stirring using a homomixer or ultrasonic dispersion can be used. As the solvent used in the above manufacturing method, an aprotic polar solvent is suitable from the viewpoint of solubility of the polymer. As the aprotic polar solvent, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphorotriamide, γ-butyrolactone, etc. are preferably used. These solvents may be used alone or in combination of two or more. Further, non-solvents for the polymer such as ketones, ethylene glycol derivatives, alcohol, and water may be added to the extent that they do not impair the solubility of the polymer. Other additives may include surfactants or adhesion improvers with the substrate. The composition thus obtained is used after adjusting its viscosity and concentration depending on the purpose and filtering it.
Filtration is usually carried out under pressure, and the filter medium may be appropriately selected depending on the purpose, and a depth filter is often used. Next, a method of using the composition of the present invention will be explained. The compositions of the present invention can be patterned using well-known microfabrication techniques using actinic radiation. First, the composition of the present invention is applied onto a suitable support. Possible coating methods include spin coating using a spinner, printing, and roll coating. The coating film thickness can be adjusted by the coating means, solid content concentration, and viscosity of the composition. Examples of the material of the support to which the composition of the present invention is applied include metals, glass, semiconductors, metal oxide insulators (eg, TiO ₂ , Ta ₂ O ₃ , SiO _{2 ,} etc.), and silicon nitride. In order to improve the adhesion between the coating film of the composition of the present invention or the polyimide film after heat treatment and the support, an adhesion aid may be used as appropriate. As adhesive aids, organosilicon compounds such as oxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, or aluminum monoethyl acetoacetate disilane are used. Aluminum chelate compounds such as isopropylate, aluminum tris (ethylacetoacetate), aluminum tris (acetylacetonate), and titanium chelate compounds such as titanium bis (acetylacetonate) are preferably used. Next, the composition of the present invention formed into a coating film on the support is irradiated with actinic radiation in a desired pattern. As the actinic radiation, ultraviolet rays and short-wavelength visible rays, that is, in the wavelength range of 300 nm to 500 nm, are preferably used. Then, a relief pattern is obtained by dissolving and removing the unirradiated areas with a developer. An appropriate developer is selected depending on the structure of the polymer. The developer is N-methyl-2, which is the solvent of this composition.
-pyrrolidone, N-acetyl-2-pyrrolidone,
Non-solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphortriamide, etc. alone or in compositions such as methanol, ethanol, isopropyl alcohol, water, methyl carbitol, ethyl carbitol, etc. It can be used as a mixture with For development, spray the above developer onto the coating surface.
Alternatively, it can be carried out by immersing it in a developer, or by applying ultrasonic waves while impregnating it. The relief pattern formed by development is
It is then preferable to wash with a rinsing liquid.
The rinsing liquid contains methanol, which has good miscibility with the developer.
Ethanol, isopropyl alcohol, butyl acetate, etc. are preferably used. The relief pattern polymer obtained by the above treatment is a precursor of a silica-containing polyimide polymer, and by heat treatment becomes a heat-resistant polymer having an imide ring or other cyclic structure. The heat treatment temperature is 135-400°C. Heat treatment is usually performed while increasing the temperature stepwise or continuously. The photosensitive polyimide composition of the present invention can be used as a passivation film for semiconductors, an interlayer insulating film for multilayer integrated circuits,
It is used to form interlayer insulating films for hybrid integrated circuits, soldering protection films for printed circuits, alignment films for liquid crystals, etc. Furthermore, it can be used as a highly heat-resistant photoresist for metal deposition and drum etching processes. It can also be applied to other known uses of polyimide. [Function] The present invention adds colloidal silica to the polyamic acid of the structural unit [], so that after heat treatment,
It becomes a polyimide-based polymer containing silica, and exhibits properties not seen in conventional polyimide-based polymers. Compounds containing a photosensitive group and an aliphatic tertiary amino group [ ] not only have the effect of imparting photosensitivity, but also have the effect of eliminating coarse secondary aggregates, thereby ensuring uniform coating, which is an essential requirement in the pattern forming process. An unexpected effect of forming a film can be obtained. Furthermore, in the present invention, when colloidal silica synthesized from alkyl silicate is used, metal impurities such as sodium, which cause deterioration of insulation properties and corrosion of metal wiring, etc., and halogens are contained in the colloidal silica. Since it does not substantially contain compounds, it has the advantage that the electrical properties and reliability of the polyimide film itself do not deteriorate. That is, by making the composition of the present invention, it is possible to obtain a composition that has both the advantages of polyimide polymers and the advantages of silica. [Effects of the Invention] Since the photosensitive polyimide composition of the present invention has the above structure, it is free of coarse secondary aggregates, pinholes, and abnormal protrusions, and exhibits excellent photosensitivity. Next, embodiments of the present invention will be described based on Examples. [Example] Examples 1 to 7 4,4'-diaminodiphenyl ether 564.5 g,
44.7g of bis(3-aminopropyl)tetramethyldisiloxane to 6800g of N-methyl-2-pyrrolidone
g to prepare an amine solution. Add benzophenonetetracarboxylic dianhydride to this amine solution.
Add 967g and react at 50℃ for 3 hours, then at 25℃
A polymer solution A of 120 poise was obtained. A compound [ ] containing a photosensitive group and an aliphatic tertiary amino group as shown in Table 1 and an aliphatic tertiary amine were added to this polymer solution A in an equivalent amount calculated with respect to the carboxyl group of the polyamic acid, and N-
Colloidal silica dispersed in methyl-2-pyrrolidone (trade name: OSCAL, Catalysts & Chemicals Co., Ltd.) and a sensitizer were added in respective amounts to the structural unit [ ] and mixed. Next, this solution was filtered through a Teflon depth filter to obtain a photosensitive solution. This photosensitive solution was applied onto a 4-inch silicon wafer using a spinner and dried at 80° C. for 1 hour. The rotation speed of the spinner was adjusted so that the coating thickness was 10 μm. The coating film thus obtained was flat and even, and adhered well to the substrate. Table 1 shows the results of evaluating these coatings for the presence of coarse secondary aggregates, pinholes, and abnormal protrusions under dark field illumination using an optical microscope with a magnification of 100 times, along with the conditions. Next, the coating film formed on the silicon wafer was set in an exposure machine (PLA-501F manufactured by Canon Inc.) and exposed through a chrome mask for 20 seconds and 5 minutes, respectively. The intensity of ultraviolet rays at this time is 10 mw/cm ²
(365nm). Development was carried out by immersion using a mixed solvent of N-methyl-2-pyrrolidone A (70 parts) and methanol (30 parts) while applying ultrasonic waves. Immediately after the unexposed areas have dissolved, continue developing for another 10 seconds, then develop with isopropanol for 20 seconds.
It was rinsed while applying ultrasonic waves and dried with a spinner. After rinsing, 135, 200, 300, 400 (℃) each
After heat treatment in nitrogen for 30 minutes, the pattern was observed using an optical microscope. The results are shown in Table 1, and good patterns were obtained in all cases. Comparative Examples 1 to 3 Experiments similar to those in the above examples were conducted using amine compounds having photosensitive groups shown in Table 2 instead of compound [ ]. The results and conditions are shown in Table 2. As is clear from the results of Examples 1 to 7 and Comparative Examples 1 to 3, the composition of the present invention contains coarse secondary aggregates,
Excellent applicability with no pinholes or abnormal protrusions.
It can also be seen that the photosensitivity is also excellent. Examples 8 to 14 Examples 1 to 14 were carried out in the same manner as in Examples 1 to 7, except that the colloidal silica in Examples 1 to 7 was changed to colloidal silica synthesized from an alkyl silicate described below. The implementation conditions and results are shown in Table 3. As a result of metal analysis of the polymer solution of Example 11, sodium ions were found to be less than 0.3 ppm, and chlorine ions were found to be less than 0.3 ppm.
It was less than 1 ppm. This is at the same level as a polymer solution that does not contain colloidal silica, and is found to be an amount that does not adversely affect insulation and reliability. As is clear from Table 3, compositions using colloidal silica synthesized from alkyl silicate have excellent coating properties and photosensitivity, and
Since it does not substantially contain sodium ions or chloride ions, it can be seen that the reliability is further improved than that of commercially available colloidal silica-based products. (Synthesis of colloidal silica) After adding 10 parts of tetraethyl silicate to a mixed solution of 100 parts of methanol and 10 parts of ammonia water (ammonia concentration 25%), the mixture was stirred at 30°C for 60 minutes.
Next, after adding 15 parts of N-methyl-2-pyrrolidone,
Ammonia, alcohol and water are distilled off at 30° C. under reduced pressure to obtain a transparent silica sol containing N-methyl-2-pyrrolidone as a solvent.

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[Table] *: Colloidal silica synthesized from alkyl silicate

Claims (1)

[Claims] 1(a) General formula (However, in the formula, R ₁ is a trivalent or tetravalent organic group,
R ₂ is a divalent organic group, and m is 1 or 2. ); (b) a compound [] containing a photosensitive group and an aliphatic tertiary amino group; and (c) an organosilica sol []; Photosensitivity characterized in that the amount S (wt%) added of the organosilica sol [] given by wt%) = SiO ₂ (g) / SiO ₂ + amount of polyamic acid (g) x 100 is 2 to 40 wt%. polyimide composition.