JPS59232122A - Organic solvent-soluble photosensitive polyimide - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel polyimide containing a photosensitive group in the main chain of the polymer, which has excellent solubility in precipitated solvents.
An organic solvent with excellent heat resistance, electrical and mechanical properties, and suitable as a material for forming insulating films and passivation films on solid-state devices in the semiconductor industry, and as an insulating material for semiconductor integrated circuits, multilayer printed wiring boards, etc. This invention relates to soluble photosensitive polyimide.

BACKGROUND ART Materials for forming insulating films and passivation films on solid-state devices in the semiconductor industry, and insulating materials for semiconductor integrated circuits, multilayer printed wiring boards, etc., are required to have high heat resistance and insulation properties. From this point of view, various proposals have been made to form the above-mentioned passivation film etc. with polyimide, which has high insulation and heat resistance (Japanese Patent Laid-Open No. 49-115
541, JP 54-116216, JP 54-116217, and JP 56-4591.
(See Publication No. 5, etc.)

However, in general, those using polyimide are solvent-insoluble and do not have photosensitive groups, and in the above proposal, the polymer containing photosensitive groups is a carboxylic acid of polyamic acid, which is a polyimide precursor. It is a modified form of acid such as amidation or esterification, and it is necessary to convert polyamic acid into polyimide during photo-curing or post-baking after photo-curing to form polyimide.

In addition, a heat-resistant photoresist composition is prepared by mixing a monomer having a photocurable group with an organic solvent-soluble polyimide (which does not have a photosensitive group) and photocuring it (Japanese Patent Laid-Open No. 54
109828, etc.), but such compositions have poor photocurability, and furthermore, the heat resistance of the polyimide after photocuring is not sufficient. Furthermore, aromatic polyimides, which have excellent heat resistance, generally have poor solubility in solvents, and therefore are not suitable for forming relief patterns, which include a step of dissolving unexposed areas in an organic solvent after photocuring.

It has also been proposed to react tetracarboxylic dianhydride with a diamine compound containing a photocrosslinkable unsaturated double bond, such as diaminochalcone, to obtain a polyimide with excellent photosensitivity and heat resistance. (Refer to Japanese Unexamined Patent Publication No. 131227/1983). However, although the polyimide obtained in this way has excellent photosensitivity, it has poor solubility in organic solvents, so it takes a long time to dissolve, which poses a practical problem in forming relief patterns.

In view of the above-mentioned current situation, the present inventors conducted various studies with the aim of providing a photosensitive polyimide that can easily form a relief pattern with excellent heat resistance, electrical and mechanical properties, and as a result, a specific An aromatic polyimide consisting of a copolycondensate of an aromatic tetracarboxylic acid or its dianhydride and two specific aromatic diamine compounds is photosensitive and soluble in organic solvents, and achieves the above objectives. I found out that it is possible.

That is, the present invention was made based on the above findings, and consists of a copolycondensate of biphenyltetracarboxylic acid or its dianhydride and two aromatic diamine compounds represented by the following general formulas (1) and (2). The present invention provides an organic solvent-soluble photosensitive polyimide.

(However, in the above formula, X is 0, C=O or -o +s
or-XX indicates o-. ) The polyimide of the present invention is
Since it uses an aromatic polyimide that is photosensitive and heat resistant, there is no need for an imidization process after image formation, and unlike conventional non-photosensitive polyimide, a separate photoresist (photoresist) for image formation is used. curable substance) is not required, and the acid component is biphenyltetracarboxylic acid or its dianhydride, and the diamine component is two aromatic diamine compounds represented by the above general formulas (1) and (2). Since it has excellent solubility in organic solvents compared to polyimide having a photosensitive group, it does not pose any problem in forming a relief pattern.

In addition, the polyimide of the present invention is a photosensitive polyamic acid (
Unlike polyimide precursors, it does not require an imidization process after image formation, so it not only simplifies the process, but also has many advantages such as no distortion or stress due to thermal effects or shrinkage on the device. It has a positive effect.

The photosensitive polyimide of the present invention will be described in detail below along with its manufacturing method.

A typical structure of the photosensitive polyimide of the present invention comprising the above copolycondensate is a copolycondensate of approximately equimolar amounts of an acid component and a diamine component, in which the diamine component is represented by the general formula (2). The molar ratio of the aromatic diamine compound to the aromatic diamine compound represented by the general formula 〇 is 3:1 to 1:
It is 3.

The photosensitive polyimide of the present invention is produced by the following method.

6- That is, the photosensitive polyimide of the present invention comprises biphenyltetracarboxylic acid or its dianhydride, which is a specific aromatic tetracarboxylic acid, and two aromatic diamine compounds represented by the above general formulas (1) and (2). The copolycondensate is synthesized by copolymerizing to form a polyamic acid, and further dehydrating and ring-closing the polyamic acid (imidization).

Specifically, the biphenyltetracarboxylic acid or dianhydride thereof used in the production of the photosensitive polyimide of the present invention is 3. 3', 4. 4'-biphenyltetracarboxylic acid or its dianhydride, 2.2'',
Examples include 3,3°-biphenyltetracarboxylic acid, or its dianhydride, and 2,3,3',4''-biphenyltetracarboxylic acid, or its dianhydride, and esters, salts, etc. of the above tetracarboxylic acids. But that's fine.

Further, specific examples of the aromatic diamine compound represented by the general formula (2) include the following:
Not limited to those.

Examples include 4.4'-diaminochalcone, 3,4'-diaminochalcone, 3',4-diaminochalcone, 3.3'-diaminochalcone, and 2.3"-diaminochalcone.

Examples include 4.4'-diaminodibenzalacetone, 3.4''-diaminodibenzalacetone, and 3.3'-diaminodibenzalacetone.

Further, specific examples of the aromatic diamine compound represented by the general formula (2) include the following:
Not limited to those.

(ll Example 4 when X is O. Examples include 4°-diaminodiphenyl ether, 3°4′-diaminodiphenyl ether, etc.

(2) Example 4 when X is C═O. Examples include 4"-diaminodiphenyl ketone and 3,4"-diaminodiphenyl ketone.

Examples of such compounds include bis(4-aminophenoxyphenyl)sulfone.

The photosensitive polyimide of the present invention is polyimide 0.5 g/N.
-Methyl-2-pyrrolidone It is preferable that the logarithmic viscosity measured at 30 DEG C. as a solution with a concentration of 100 nl is in the range of 0.1 to 1.5, particularly 0.2 to 1.0.

To explain in more detail the production of the photosensitive polyimide of the present invention, when synthesizing the copolycondensate, the proportions of the biphenyltetracarboxylic acid or its dianhydride and the two aromatic diamine compounds used are approximately equimolar. The preferable ratio of the aromatic diamine compound represented by the above general formula and the aromatic diamine compound represented by the above general formula ○ is 3:1 to 1:3. Preferably, these synthetic reactions are carried out in a two-step reaction in which a polymerization reaction is first carried out and then an imidization reaction is carried out at a relatively low temperature.

That is, first, the temperature is lower than 100°C, preferably 8°C in an organic solvent.
A polymerization reaction is carried out at a reaction temperature of 0°C or lower for 1 to 48 hours, and then, after diluting the polyamic acid solution obtained by this polymerization reaction with an organic solvent, acetic anhydride is carried out at a reaction temperature of 100°C or lower, preferably 80°C or lower. It is preferable to add an imidizing agent such as pyridine, tertiary amine, etc. and carry out the imidization reaction for 0.5 to 5 hours, and as a result, the above-mentioned copolycondensate is synthesized to obtain the polyimide of the present invention.

Examples of the organic solvent in the polymerization reaction and the imidization reaction include N,N-dimethyl sulfoxide, N,
N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone, hexamethylphosphoamide and the like are used.

In the present invention, the copolycondensate is produced by polymerizing the biphenyltetracarboxylic acid or its dianhydride and the aromatic diamine compound in an organic solvent at a high temperature of -102100°C or higher in one step. - It can also be synthesized by performing an imidization reaction, but as described above, a stable product can be obtained by carrying out the process in two steps.

When the photosensitive polyimide of the present invention is used as a material for forming a relief pattern, it is used as a solution dissolved in an organic solvent. This organic solvent includes N,
Examples include N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, hexamethylphosphoamide, etc., and photosensitive. The preferred concentration of the polyimide solution is 5-30%.

Furthermore, a sensitizer, a photopolymerization initiator, and a light-polymerizable compound having an ethylenically unsaturated group can be added to the photosensitive polyimide solution, if necessary.

As the sensitizer and photoinitiator, Mihira 1-
-zketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, 2-t-butylanthraquinone, 1
．． 2-benzo-9,10-anthraquinone, 4.4"
Examples include -bis(diethylamino)benzophenone, acetophenone, benzophenone, thioxanthone, 1,5-acenaphthene, N-acetyl-4-nitro-1-naphthylamine, and the amount added is based on 100 parts by weight of photosensitive polyimide. It is preferably 0.1 to 10 parts by weight.

Further, as the photopolymerizable compounds having ethylenically unsaturated groups, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tolmethylolpropane tri( meth)acrylate, tetramethylolmethanetetra(meth)acrylate, N.

Examples include N'-methylenebis(meth)acrylate and diethylaminoethyl(meth)acrylate.

According to the photosensitive polyimide of the present invention, a relief pattern can be formed in the following manner by adjusting the photosensitive polyimide solution as described above.

That is, first, the above-mentioned photosensitive polyimide solution is applied to a substrate and dried to remove the organic solvent.

Coating onto the substrate can be performed using, for example, a rotary coater. The coating film is dried at a temperature of 150°C or lower, preferably 100°C or lower. At this time, the pressure may or may not be reduced. After drying, a negative photomask chart is placed on the coated film, and active light such as ultraviolet rays, visible light, electron beams, and X-rays is irradiated. The unexposed areas are then washed away with a developer to obtain a polyimide relief pattern. Examples of the above developer include N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, N-methyl-
A solvent such as 2-pyrrolidone or hexamethylphosphoamide or a mixed system of the solvent and methanol or ethanol can be used.

As mentioned above, the photosensitive polyimide of the present invention has a photosensitive group (photopolymerizable group) in the poly-13-rimer, and the acid component is biphenyl carboxylic acid or its dianhydride, and the diamine Since it is a copolycondensate whose components are an aromatic diamine compound represented by the above general formula (1) and an aromatic diamine compound represented by the above general formula (2), it has excellent solubility in organic solvents, and therefore is suitable for photochemistry. A relief pattern can be easily formed by manual means, and when forming a relief pattern, the polyimide of the present invention can be
In order to have photosensitivity and maintain the heat resistance of polyimide,
Unlike conventional non-photosensitive polyimide, it does not require a separate photocurable material for image formation, and unlike photosensitive polyamic acid (polyimide precursor), it does not require an imidization process after image formation. Therefore, it not only simplifies the process, but also
It has many excellent effects such as no thermal influence on the element, no strain or stress due to shrinkage, etc. Moreover, the relief pattern formed from the photosensitive polyimide of the present invention is
It has excellent heat resistance, electrical and mechanical properties, and is not only effective as an insulating film 14- or a passivation film for solid-state devices in the semiconductor industry.
It can be used as an insulating film or solder resist for multilayer wiring structures of hybrid circuits and printed circuits.

Examples showing the production of the photosensitive polyimide of the present invention and various physical property tests showing the effects of the photosensitive polyimide of the present invention and their results are listed below, along with comparative examples.

Example I N-methyl-2-pyrrolidone (NMP) 11.02
Add 1580 mg of 2.3.3°, 4′-biphenyltetracarboxylic dianhydride, 710 mg of 3.3′-diaminodibenzalacetone, and 538 mg of 4.4′-diaminodiphenyl ether to m1, and stir at 30°C for 5 hours. The mixture was reacted to obtain polyamic acid.

Next, 4.1.3 ml of NMP was added to this polyamic acid to dilute it, followed by 10.96 g of acetic anhydride and 4.1 ml of pyridine.
24g, benzene 8.0ml and NMP 6.89m
1 and reacted at 50°C for 2 hours to obtain imidized product 1.
Ta.

Methanol was added dropwise to the imidide solution to precipitate polyimide, which was filtered off to obtain yellow polyimide powder (polyimide of the present invention).

Example 2 1737 mg of 2.3.3',4''-biphenyltetracarboxylic dianhydride and 3',4-
702 mg of diaminochalcone and 591+ ng of 4,4'-diaminodiphenyl ether were added, and the mixture was stirred and reacted at 30° C. for 5 hours to obtain polyamic acid.

Next, 44.3 ml of NMP was added to this polyamic acid to dilute it, and then 12.06 g of acetic anhydride and 4.6 g of pyridine were added.
7 g of benzene, 8.6 ml of benzene, and 7.38 ml of NMP were added, and the mixture was reacted at 50° C. for 2 hours to obtain an imidized product.

Methanol was added dropwise to the imidide solution to precipitate polyimide, which was filtered off to obtain yellow polyimide powder (polyimide of the present invention).

Example 3 Instead of the 4,4”-diaminodiphenyl ether used in Example 1, bis(4-aminophenoxyphenyl)
A polyimide of the present invention was obtained in the same manner as in Example 1 using sulfone.

Physical property test The following (11
The physical property tests (6) to (6) were conducted and the results shown in the table below were obtained.

+11 Viscosity of Polyimide The logarithmic viscosity of a polyimide solution having a concentration of 0.5 g of polyimide and 100 ml of NMP was measured at 30°C.

(2) Polyimide film forming property A polyimide film with a thickness of about 10 μm was created on a glass plate, soaked in water, peeled off, and bent at 180 degrees. Those in which cranking occurred during film formation were marked as ×.

(3) Solubility of polyimide in NMP The solubility (wt%) of polyimide in NMP was measured at room temperature.

(4) Solubility of polyimide film A polyimide film with a thickness of about 17-10 μm prepared from a 10% NMP solution of polyimide is immersed in NMP at room temperature and stirred, and the solubility is measured by the time it takes for the film to dissolve. did.

(5) Starting temperature of thermal decomposition The starting temperature of weight loss was measured using a differential thermobalance TG-DSC manufactured by Rigaku Denki ■.

(6) Coating a 10% NMP solution of photocurable polyimide onto a glass plate using a spin coating machine (2000-5000 rpm),
The thin film was dried at 50° C. for 5 hours under a reduced pressure of 1 to 2 n++ nt1 g to form a thin film several microns thick (see the table below), and this thin film was subjected to the following photosensitivity and resolution tests.

■Photosensitivity The above thin film was coated with an ultra-high pressure mercury lamp (jet light 2kW) at an illuminance of 7.2mW/c+ll (350mJJ).
) to photocure, and the amount of light irradiation (J) until photocuring.
/c) was measured.

■Resolving power As a test chart for the above thin film, a negative type test chart manufactured by Toppan Printing 18- ■ (Tosoban Test Chart N)
A relief pattern was formed using a minimum line of 0.98±0.25μ), and the quality of the pattern was determined.

Comparative Example I 722 mg of pyromellitic dianhydride in 6.2 ml of NMP
and 788 mg of 3゛,4-diaminochalcone were added, and 30
The reaction mixture was stirred at ℃ for 5 hours to obtain polyamic acid. The logarithmic viscosity of this polyamic acid was 0.52.

Next, 22 ml of NMP was added to this polyamic acid to dilute it, and then 6.7 g of acetic anhydride, 2.6 g of pyridine, 4.3 ml of benzene, and 3.7 ml of NMP were added and reacted at 50°C. After 1 minute, a yellow polyimide powder was formed. was precipitated. The reaction was continued for an additional 120 minutes.

After filtering off the precipitated yellow polyimide powder, an attempt was made to dissolve 10+ng of this polyimide powder in NMploml, but it did not dissolve.

Therefore, it was impossible to measure the photosensitivity and resolution of this polyimide.

patent applicant Ube Industries Co., Ltd. Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] An organic solvent-soluble photosensitive polyimide consisting of a copolycondensate of biphenyltetracarboxylic acid or its dianhydride and two aromatic diamine compounds represented by the following general formulas (1) and (2). . (However, in the above formula, X is O, C=O or