JPH11158275A - Dehydrative ring closure of heat-resistant polymer precursor and heat-resistant coating agent containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantitatively perform the dehydrative ring closure reaction of a heat-resistant polymer precursor while omitting a re-precipitation step by mixing a solution prepared by dissolving a heat-resistant polymer precursor in a solvent with polymer particles containing acid anhydride groups and/or dehydrating groups and being insoluble in the solution to effect the dehydrative ring closure reaction. SOLUTION: A solution prepared by dissolving a heat-resistant polymer precursor containing at least one, desirably, polyamide, polyhydroxyamide, polythiohydroxyamide, polyhydroxyamide-amic acid, or polycarboxyamide is mixed with polymer particles containing acid anhydride groups and/or dehydrating groups, desirably, an acid-anhydride-modified crosslinked PS gel and/or an acid-anhydride-modified crosslinked acrylic resin, and being insoluble in the solution of the heat-resistant polymer precursor to effect the dehydrative ring closure reaction. After this reaction, the polymer particles are removed to recover a heat-resistant coating agent comprising a partially or perfectly dehydratively ring-closed heat resistant polymer precursor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dehydration ring-closing method capable of quantitatively performing a dehydration ring-closure reaction of a heat-resistant polymer precursor and eliminating the need for removing a reagent used for the dehydration ring-closure reaction out of the system. The present invention relates to a heat-resistant coating agent which is important in the field of electronics using a heat-resistant polymer that has been closed or a heat-resistant polymer precursor solution that has been partially dehydrated and closed.

[0002]

2. Description of the Related Art A heat-resistant polymer has excellent heat resistance,
Because of its chemical resistance, it is used in the field of paints such as sheet-like molded articles and enamel coatings, the field of aerospace such as adhesives for composite materials, and the field of electronics such as insulating films. Examples of such a heat-resistant polymer precursor include polyamic acid as a polyimide precursor, polyhydroxyamide as a polybenzoxazole precursor, polythiohydroxyamide as a polybenzothiazole precursor, and polyamino as a polyimidazole precursor. Amides are known (by Kobe Heat-resistant polymer Baifukan
(1969)). In order to produce many such heat-resistant polymers, for example, in the case of a polyimide resin, a polyimide precursor can be obtained by reacting tetracarboxylic acid or its dianhydride or dichloride with a diamine in a polar solvent (C.I. E. Sroog et al., Journal.
of Polymer Science, Par
tA-3, 1373 (1965)). Then heat treatment,
It is common to perform a dehydration ring closure reaction by a chemical treatment to obtain a polyimide resin. In the case of a polybenzoxazole resin, a polyhydroxyamide is obtained by reacting a dicarboxylic acid or a dichloride or diester thereof with bisaminophenol, followed by dehydration and ring closure to obtain a polybenzoxazole. In this case, a long-time heating reaction at a temperature of 200 ° C. or more is required to advance the dehydration ring closure without using a catalyst. For this reason, the required energy amount becomes enormous. Further, when a dehydration ring-closing catalyst is used in combination, from room temperature to 200 ° C.
The dehydration ring closure can proceed at temperatures up to. Examples of such a catalyst for dehydration ring closure include acids such as phosphoric acids, toluenesulfonic acids, benzoic acid, crotonic acid, and acetic acid;
-Lactones such as valerolactone, amines such as pyridine, isoquinoline, and triethylamine, or salts thereof with acids alone or in combination of two or more thereof have been used (JP-A-7-157560). However, when such a dehydration ring-closing catalyst is used in combination, in order to remove the dehydration ring-closing catalyst remaining in the system after the completion of the dehydration ring-closing reaction, the heat-resistant polymer solution is poured into a poor solvent such as water or methanol, It was necessary to precipitate the heat-resistant polymer, filter, dry, and then redissolve.

In order to avoid this problem, there has been proposed a method of imidizing a polyimide precursor in which a cation exchange resin or an anion exchange resin is used as a dehydration ring closure catalyst (Japanese Patent Application Laid-Open No. 9-169841). In this method, after the dehydration ring-closing reaction, the dehydration ring-closing catalyst can be removed only by filtration, but a quantitative dehydration ring-closing reaction cannot be performed according to the amount of the catalyst.

[0004] Such quantitative dehydration ring closure is carried out by acid anhydrides such as acetic anhydride and trifluoroacetic anhydride, dicyclohexylcarbodiimide, and benzotriazole-
A dehydrating agent such as 1-yl-oxy-tris (dimethylamino) phosphonium hexafluorophosphate was obtained by adding an amount necessary for performing dehydration ring closure (US Pat. No. 3,179,630). . However, after the reaction, it is necessary to remove the acid anhydride and the dehydrating agent that promote such quantitative dehydration ring closure from the solution.

[0005]

SUMMARY OF THE INVENTION The present invention solves such a problem, and the dehydration and ring closure of the heat-resistant polymer precursor occurs in proportion to the amount of the added catalyst, and the removal of the catalyst after the dehydration and ring closure reaction is carried out by filtration. It is intended to be something that can be done only by.

[0006]

The present invention for solving the above-mentioned object has the following constitution. That is, (a) a solution obtained by dissolving a heat-resistant polymer precursor in a solvent soluble therein and (b) polymer particles containing an acid anhydride group and / or a dehydration group and insoluble in the solution (a) are mixed. And performing a dehydration ring-closing reaction.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-resistant polymer precursor in the present invention includes polyamic acid, which is a polyimide precursor,
Polyhydroxyamide that is a polybenzoxazole precursor, polythiohydroxyamide that is a polybenzothiazole precursor, polyaminoamideimide that is a polybenzimidazole precursor, oxazole ring, and other polymers having a cyclic structure. . By having a ring structure, heat resistance and solvent resistance are dramatically improved.

In the present invention, the polymer particles containing an acid anhydride group and / or a dehydration group and insoluble in a solution in which a heat-resistant polymer precursor is dissolved include, for example, polystyrene modified with maleic anhydride and divinylbenzene. Cross-linked with a monomer having a divalent or trivalent or higher vinyl group and insoluble in a solvent, or an acrylic polymer modified with maleic anhydride is converted to a trivalent or higher acrylic monomer such as trimethylolpropane triacrylate. And those insoluble in a crosslinked solvent. In addition, as the acid anhydride group, a carboxylic acid anhydride group,
By using a vinyl monomer such as a thionyl chloride group, a phosphite group, or a carbodiimide group as a group such as a phosphonic anhydride group or a condensing agent group, a polymer insoluble in a target solvent can be obtained. it can.

Further, a basic liquid such as pyridine or triethylamine, a product obtained by crosslinking polystyrene modified with vinylpyridine with divinylbenzene, or a commercially available ion exchange resin having an amino group is added as a catalyst for dehydration condensation. You can also.

As a method for synthesizing the heat-resistant polymer precursor in the present invention, a method of reacting a tetracarboxylic dianhydride with a diamine compound at a low temperature (CE Sroog).
Et al., Journal of Polymer Scie
nce, Part A-3, 1373 (196
5)), a method of obtaining a diester from tetracarboxylic dianhydride and an alcohol and then reacting the diester with an amine in the presence of a condensing agent (Japanese Patent Application Laid-Open No. 61-72022). To obtain a diester, and then the remaining dicarboxylic acid is converted to an acid chloride and reacted with an amine (JP-A-55-30207).

It is also possible to impart photosensitivity to the heat-resistant polymer precursor of the present invention and use it as a photosensitive heat-resistant polymer precursor. As a method of imparting photosensitivity,
A compound in which a compound having an unsaturated double bond is bonded to a polymer side chain (JP-A-60-26033) and a compound in which an amino compound having an unsaturated double bond is mixed (JP-B-59-52822). And naphthoquinonediazidesulfonic acid esters (Japanese Patent Publication No. 1-46).
No. 862).

If necessary, a surfactant such as ethyl lactate or propylene glycol monomethyl ether may be used for the purpose of improving the coatability between the heat-resistant polymer precursor or the photosensitive heat-resistant polymer precursor and a substrate such as silicon. Esters such as teracetate; alcohols such as ethanol; ketones such as cyclohexanone and methyl isobutyl ketone; ethers such as tetrahydrofuran and dioxane.
Ters may be mixed. In addition, inorganic particles such as silicon dioxide and titanium dioxide, or powder of polyimide can also be added.

Further, in order to enhance the adhesion to an underlying substrate such as a silicon wafer, a silane coupling agent, a titanium chelating agent, etc. are added to the varnish of the photosensitive heat-resistant polymer precursor composition in an amount of 0.5 to 10% by weight. Alternatively, the underlying substrate can be pre-treated with such a chemical solution.

When added to the varnish, a silane coupling agent such as methylmethacryloxydimethoxysilane and 3-aminopropyltrimethoxysilane, a titanium chelating agent and an aluminum chelating agent are added to the polymer in the varnish in an amount of 0.5 to 10%. % By weight.

When treating the substrate, the above-mentioned coupling agent is added to a solvent such as isopropanol, ethanol, methanol, water, tetrahydrofuran, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, diethyl adipate and the like. The solution in which 5 to 20% by weight is dissolved is subjected to surface treatment by spin coating, dipping, spray coating, steam treatment, or the like. In some cases, then 50 ° C to 300 ° C
The reaction between the substrate and the coupling agent proceeds by applying a temperature up to

Next, a method for forming a heat-resistant resin pattern using the above photosensitive heat-resistant polymer precursor composition will be described.

The photosensitive heat-resistant polymer precursor composition is applied on a substrate. As the substrate, a silicon wafer, ceramics, gallium arsenide, or the like is used, but is not limited thereto. Examples of the coating method include spin coating using a spinner, spray coating, and roll coating. The coating thickness is different depending on the coating method, the solid concentration of the composition, the viscosity, and the like.
It is applied so as to have a thickness of 0.1 to 150 μm.

Next, the substrate coated with the photosensitive heat-resistant polymer precursor composition is dried to obtain a photosensitive heat-resistant polymer precursor composition film. Drying is oven, hot plate,
It is preferable to use infrared rays or the like for 1 minute to several hours in the range of 50 ° to 150 °.

Next, the photosensitive heat resistant polymer precursor composition film is exposed to actinic radiation through a mask having a desired pattern. Actinic rays used for exposure include ultraviolet rays, visible rays, electron beams, and X-rays. In the present invention, i-line (365 nm) and h-line (405 n) of a mercury lamp are used.
m) and g-line (436 nm) are preferably used.

The pattern of the heat-resistant polymer precursor composition is formed by removing the unexposed portion in the case of a negative type and the exposed portion in the case of a positive type using a developer after exposure. You. As a developing solution, an aqueous solution of tetramethylammonium, diethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, diethylamine, methylamine, dimethylamine, dimethylaminoethyl acetate, dimethylaminoethanol, dimethylamine Aminoethyl methacrylate, cyclohexylamine,
An aqueous solution of an alkaline compound such as ethylenediamine or hexamethylenediamine is preferred. In some cases, a polar solvent such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, γ-butyrolactone, dimethylacrylamide, etc.
Alcohols such as methanol, ethanol, and isopropanol; esters such as ethyl lactate and propylene glycol monomethyl ether acetate; ketones such as cyclopentanone, cyclohexanone, isobutyl ketone, and methyl isobutyl ketone, alone or in combination. It may be added. After development, it is rinsed with water. Here, rinsing treatment may be performed by adding alcohols such as ethanol and isopropyl alcohol, esters such as ethyl lactate and propylene glycol monomethyl ether acetate to water.

After development, the film is converted into a heat-resistant polymer film by applying a temperature of 200 to 500 degrees. This heat treatment is carried out for 5 minutes to 5 hours while selecting the temperature and increasing the temperature stepwise, or while selecting a certain temperature range and continuously increasing the temperature. As an example, heat treatment is performed at 130 degrees, 200 degrees, and 350 degrees for 30 minutes each. Alternatively, a method of linearly raising the temperature from room temperature to 400 ° C. over 2 hours may be used.

The heat-resistant polymer film formed from the photosensitive heat-resistant polymer precursor composition according to the present invention is used for a passivation film of a semiconductor, a protective film of a semiconductor element, an interlayer insulating film of a multilayer wiring for high-density mounting, and the like. Used for

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments.

Measurement of Ring Closure Ratio Using a 4-inch silicon wafer, a measurement sample was spin-coated using a coater developer SCW-636 manufactured by Dainippon Screen Co., Ltd. so as to have a film thickness of about 7 μm. Prebaking was performed at 80 ° C. for 3 minutes and at 100 ° C. for 1 minute using a hot plate. This wafer is subjected to a Fourier transform infrared absorption spectrophotometer FT manufactured by JASCO Corporation.
The infrared absorption spectrum was measured using / IR-5000. Reference measurement was performed using a 4-inch silicon wafer on which nothing was applied. The measurement of ring closure is
The wave number of each absorption was used. For example, in the case of imidization absorption near 1770 cm ^-1 in the case of oxazole of using absorption appears near 1390 cm ^-1. In addition, using an inert oven DT42 manufactured by Yamato Scientific Co., Ltd., infrared absorption of a sample heat-treated at 350 ° C. for 1 hour after increasing the temperature to 350 ° C. for 30 minutes in nitrogen at 200 ° C. for 30 minutes. The magnitude of each characteristic absorption of the spectrum was taken as the magnitude of the absorption when the ring was closed at 100%, and the dehydration ring closure rate was calculated in% from the intensity ratio with the absorption intensity.

Synthesis Example 1 Synthesis of crosslinked polystyrene having an acid anhydride group 0.8 g of polyvinyl alcohol having a saponification degree of 98% (“Gohsenol” GM-14 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
And a polyvinyl alcohol having a saponification degree of 89 to 90% ("GOHSENOL" GM-1 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
4) 0.08 g was left in 30 ml of water at room temperature for 30 minutes to swell. Subsequently, the dispersion was heated on a water bath at 90 to 95 ° C. to dissolve the polyvinyl alcohol in water. This was filtered to remove the gel.

26.0 g (0.25 mol) of styrene monomer and 5.8 g of divinylbenzene (0.0% at 55% purity)
245 mol) and maleic anhydride 1 in 10 ml of toluene.
A liquid in which 3.2 g (0.135 mol) and 0.5 g of benzoyl peroxide were dispersed was placed in a 300 ml three-necked flask equipped with a thermometer, a reflux tube, and a stirring blade. In addition, the mixture was gradually heated from room temperature to 90 ° C. After reacting at 90 ° C. for 3 hours, the temperature was lowered, stirring was stopped, the mixture was transferred to a 2 liter beaker, water was added, and the mixture was stirred for a while. Thereafter, the mixture was filtered, washed with water, and put in acetone. After standing in acetone overnight, the mixture was filtered, washed with acetone, dried overnight in a vacuum dryer at 120 ° C. to remove volatile components, and further subjected to acid anhydride. After the temperature was returned to room temperature by vacuum, it was taken out and used.

Examples 1-3, Comparative Examples 1-3 In a three-necked flask equipped with a 500 ml stirring blade, a nitrogen inlet tube and a thermometer, 2,2'-bis (trifluoromethyl)- 16.0 g (0.045) of 4,4'-diaminobiphenyl (manufactured by Wakayama Seika Kogyo Co., Ltd.)
Mol) and 1.24 g (0.005 mol) of 1,3-bis (3-aminopropyl) tetramethyldisiloxane (manufactured by Toray Dow Corning Silicone Co., Ltd.) were dissolved in 50 g of N-methylpyrrolidone. Where 3,3 ',
15.5 g of 4,4'-diphenylethertetracarboxylic dianhydride (manufactured by Daicel Chemical Industries, Ltd.)
5 mol) was added as a powder. After continuing stirring at room temperature for 1 hour, stirring was continued at 50 ° C. for 4 hours to obtain a polyamic acid (polyimide precursor) solution.

The dehydration ring closure reagent shown in Table 1 was added to this solution, and the dehydration ring closure rate (imidation rate) was measured. As shown in Table 1, in the case where the polymer gel having an acid anhydride group was used, a dehydration ring closure rate corresponding to the amount of the added catalyst was obtained without a reprecipitation step. Further, in the case of using an ion exchange resin as a catalyst, it is difficult to adjust the dehydration ring closure rate according to the amount of the catalyst.

[0029]

[Table 1] Anhydride polymer: polymer synthesized in Synthesis Example 1 Ion exchange resin: Amberlyst A manufactured by Oregano Corporation
-21 (weakly alkaline type).

Comparative Example 4 Example 1 was repeated except that acetic anhydride was used as the dehydrating ring closing reagent.
An experiment was performed in the same manner as in the above. Unlike Examples 1 to 3 using the anhydride polymer synthesized in Synthesis Example 1, the use of acetic anhydride requires a reprecipitation step, which complicates the process.

Examples 4 and 6, Comparative Examples 5 and 6 36.6 g (0.1 mol) of bis (3-amino-4-hydroxyphenyl) hexafluoropropane was dissolved in 100 g of dimethylacetamide. Glycidyl allyl ether g (0.5 mol) was added thereto and cooled to 5 ° C. A solution of 21.0 g (0.103 mol) of isophthalic chloride dissolved in 50 g of acetone was added dropwise to this solution so that the temperature of the reaction solution did not exceed 10 ° C. After the completion of the dropwise addition, the mixture was reacted at 5 ° C. for 2 hours and then at 20 ° C. for 4 hours.
A solution of polyhydroxyamide (polybenzoxazole precursor) was obtained.

The dehydration ring closure reagent shown in Table 2 was added to this solution, and the dehydration ring closure rate (oxazole conversion rate) was measured. As shown in Table 2, in the case of using a polymer gel having an acid anhydride group, there is no reprecipitation step, and a dehydration ring closure rate corresponding to the amount of the added catalyst can be obtained. In the case of using an ion exchange resin as a catalyst, dehydration ring closure (oxazole formation) hardly progresses.

[0033]

[Table 2] Anhydride polymer: polymer synthesized in Synthesis Example 1 Ion exchange resin: Amberlyst A manufactured by Oregano Corporation
-21 (weakly alkaline type).

Comparative Example 7 Example 4 was repeated except that acetic anhydride was used as the dehydrating ring closing reagent.
An experiment was performed in the same manner as in the above. Unlike Examples 4 to 6 using the anhydride polymer synthesized in Synthesis Example 1, the use of acetic anhydride requires a reprecipitation step, which complicates the process.

[0035]

According to the present invention, a heat-resistant polymer precursor can be subjected to dehydration and ring closure by a simple process which does not require a reprecipitation step.

Claims (4)

[Claims] 1. A solution of (a) a heat-resistant polymer precursor dissolved in a solvent soluble therein, and (b) a polymer containing an acid anhydride group and / or a dehydration group and insoluble in the solution of (a). A method for dehydrating and ring-closing a heat-resistant polymer precursor, which comprises mixing particles and performing a dehydration and ring-closing reaction. 2. After the dehydration and ring closure according to the method of claim 1, the polymer particles are removed and a heat-resistant resin polymer precursor partially dehydrated and ring-closed or a heat-resistant resin polymer precursor completely dehydrated and ring-closed is used. A heat-resistant coating agent characterized by becoming. 3. The heat-resistant polymer according to claim 1, wherein the heat-resistant polymer precursor contains at least one of polyamic acid, polyhydroxyamide, polythiohydroxyamide, polyhydroxyamidamic acid, and polycarboxyamide. A method for dehydration ring closure of a polymer precursor. 4. It contains an acid anhydride group and / or a dehydrating agent,
And polymer particles insoluble in the solution of the heat-resistant resin precursor,
The method for dehydrating and cyclizing a heat-resistant polymer precursor according to claim 1, wherein the method is at least one of an acid anhydride-modified crosslinked polystyrene gel and an acid anhydride-modified crosslinked acrylic resin.