JPS5813088B2 - Method for producing siloxane-modified polyimide precursor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a siloxane-modified polyimide precursor using diaminosiloxane as part of a diamino compound polymerized with an aromatic tetracarboxylic dianhydride.

Conventionally, surface protection films and interlayer insulating films of semiconductor devices have been formed by CVD.
(Chemical Vapor Depositio
The use of silicon dioxide has been considered using methods such as n), but its application to semiconductors has been delayed due to drawbacks such as the tendency for thin silicon dioxide films to crack and the presence of many pinholes. There is.

In recent years, heat-resistant polymers, particularly polyimide, have been attracting attention in this field as a new material to replace the above-mentioned silicon dioxide film.

In other words, this heat-resistant polymer has sufficient heat resistance to withstand wire bonding, and also has excellent electrical insulation properties.
It has many excellent advantages such as low stress strain and mechanical strength.
Organic materials are attracting attention because they do not cause cracks even when made into thick films, and pinholes are suppressed to a small extent.However, silicone rubber, silicone face, etc. have traditionally been used as junction protection films for diodes. It has the function of protecting the p-N junction of semiconductor elements, but silicon compounds are generally essentially permeable to water, and when semiconductors are comprehensively evaluated, they have the function of protecting the p-N junction of semiconductor devices. A decline in reliability was unavoidable.

In recent years, heat-resistant polymers such as polyimide, which themselves have excellent moisture resistance, have been used for this junction protective film.

In this way, heat-resistant polymers, mainly polyimide, are being considered as protective films or insulating films for various semiconductor processing, but these types of heat-resistant polymers can be used on substrates such as silicon wafers and glass. It has the disadvantage of poor adhesion to the surface and is difficult to adhere to, and as a result, the reliability of semiconductor devices and the like has not been satisfactory.

For this reason, various proposals have been made to improve the adhesion of the above-mentioned heat-resistant polymers, and one of them is to create a polyimide precursor using a polymerization reaction between an aromatic tetracarboxylic dianhydride and a diamino compound. When synthesizing, there is a method of using diaminosiloxane as the above diamino compound.

This method introduces Si-O-Si bonds derived from diaminosiloxane into the molecular skeleton, and these bonding parts form chemical bonds with silicon atoms in silicon-containing materials such as silicon wafers and glass. The purpose is to improve adhesion by using these as active sites for adhesion to silicon-containing materials.

However, in the above proposed method, diaminosiloxane is used in a considerable proportion of the diamino compound or as all of the diamino compound, so even if the adhesion can be improved, the moisture resistance properties of the polyimide film will be significantly impaired. There's a problem.

Further, excessive use of diaminosiloxane was not necessarily preferable in terms of polyimide's inherent i-property, electrical insulation properties, mechanical strength, etc.

Furthermore, in the proposed method, a polyimide precursor synthesized using an excess of diaminosiloxane and a polyimide precursor synthesized without using diaminosiloxane at all, that is, using a diamine that does not contain a silicon atom in the molecule. There is also a method of using a mixture as a mixture, but even in this case, not only does the silicon content in the mixture cause the same problems as mentioned above, but also because it is a mixture, the adhesion, moisture resistance, and other general characteristics may vary depending on the lot. It was difficult to obtain stable performance due to the large variations between the two.

On the other hand, this type of siloxane-modified polyimide precursor is
It is desirable to use a polymer with high intrinsic viscosity due to heat resistance and other general properties, but in this case, as with conventional siloxane-unmodified polyimide precursors, the solution viscosity will be high and the solid content concentration will be lower than practical. There is a problem that I cannot get it.

For example, the feed concentration during the synthesis of polyimide precursors is generally set to be at least 5 to 15% by weight for economical reasons, but even with such a low feed concentration, spin In order to obtain a solution viscosity suitable for coating, desopping or brushing, a considerable amount of dilution must be made during the polymerization reaction.

Such a dilution operation causes variations in solution viscosity between production lots and complicates the coating process, and also causes repellency and uneven thickness in the formed coating film due to a significant decrease in solid content concentration. This results in an adverse effect on the performance of the polyimide film.

In view of the above, the present invention provides a polyimide that exhibits a viscosity that allows coating in a highly concentrated state, has excellent adhesion to the substrate surface, and has good moisture resistance. This discovery was made as a result of extensive research in order to obtain a siloxane-modified polyimide precursor that has insulation properties, mechanical strength, etc.

That is, this invention provides the following general formula; (RI is a divalent organic group, R' is a monovalent organic group, and n
is an integer from 1 to 1000) A diamino compound consisting of a diamino siloxane represented by: A first step of obtaining a solution of a siloxane-modified polyimide precursor having a silicon content of 0.5% by weight or less by carrying out a polymerization reaction at a ratio of ~4% by mole; a second step of reducing the intrinsic viscosity of the precursor by heating and aging at 80°C.
This relates to a method for producing a precursor.

As described above, in this invention, the diaminosiloxane used to improve the adhesion of polyimide is necessary and sufficient within the above specified range. Since the siloxane bonds that are easily broken by decomposition or acid or alkali are extremely small, the moisture resistance properties of polyimide are not reduced, and polyimide's inherent heat resistance, electrical insulation, mechanical strength, etc. are not impaired. I found out that there is nothing to worry about.

On the other hand, the siloxane-modified polyimide precursor synthesized using diaminosiloxane in the above-mentioned proportion has the same drawback as conventional precursors in that it has a high solution viscosity.

However, according to the present invention, when the polyimide precursor solution in the polymerization reaction is further heated and aged at a specific temperature,
Molecular cleavage or rearrangement of the precursor lowers its intrinsic viscosity, resulting in a solution viscosity that can be coated without dilution with a solvent, and when this method is used to form a solution with high concentration and low viscosity. It has been discovered that, in addition to the excellent adhesion and moisture resistance properties of a polyimide film achieved by the above-mentioned means, it has almost no adverse effect on heat resistance, mechanical strength, electrical insulation, etc. It is.

In the diaminosiloxane represented by the general formula (1) in the present invention, two RIs and each R' in the formula may be the same or different, and a wide variety of conventionally known diaminosiloxanes are included.

Typical examples are as follows.

The diamine that does not contain a silicon atom in its molecule (hereinafter simply referred to as a silicon-free diamine) used in this invention has the following general formula (2); (R2 is a divalent organic group that does not contain a silicon atom) It includes aromatic diamines, aliphatic diamines, and alicyclic diamines represented by the formula, in which R2 is R in the general formula (1).
It may be the same as or different from I.

Particularly preferred are aromatic diamines, representative examples of which include metaphenylenediamine, paraphenylenediamine, 44'-diaminodiphenylmethane,
4,4-diaminodiphenyl ether, 2,2'-bis(4-7minophenyl)propane, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl Sulfide, benzidine, penzidine-3,3'-dicarboxylic acid, penzidine-3,3'-disulfonic acid, penzidine-3-monocarboxylic acid, penzidine-3-monosulfonic acid, 3,3
'-dimethoxy-benzidine, parabis(4-aminophenoxy)benzene, metabis(4-aminophenoxy)benzene, metaxylylene diamine, paraxylylene diamine, and the like.

In this invention, the aromatic tetracarboxylic dianhydride polymerized with the diamino compound consisting of the above diaminosiloxane and silicon-free diamine has the following general formula (3); (Ar is a tetravalent organic group) ), and representative examples include pyromellitic dianhydride, 3, 3', 4,
4'-Benzophenonetetracarboxylic dianhydride, 3.
3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propani Anhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride , 2,2'-bis(2,3-dicarboxyphenyl)propanihydride,
1,1'-bis(2,3-dicarboxyphenyl)ethane dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride Examples include anhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, and the like.

A particularly suitable aromatic tetracarboxylic dianhydride for this invention is 3,3',4,4'-biphenyltetracarboxylic dianhydride.

When this dianhydride is used, it is possible to produce polyimide with excellent electrical properties in a high-temperature, high-humidity atmosphere, such as a pressure Kutzker test (hereinafter simply referred to as PCT) at 121°C and 2 atm, that is, extremely good moisture resistance. Thus, the performance as a protective film or an insulating film can be greatly improved.

Of course, the moisture resistance can be improved by using other dianhydrides, but it is desirable to increase the thickness of the film when it is used as a passivation film.

In the first step of the present invention, it is necessary to simultaneously polymerize the diaminosiloxane and the silicon-free diamine with the aromatic tetracarboxylic dianhydride; for example, after polymerizing both diamino compounds separately, The mixing method causes variations in adhesion and moisture resistance, making it impossible to stabilize quality.

As mentioned above, the diaminosiloxane used in this polymerization reaction is 1 to 4 mol% of the total amount of diamino compounds.
, is preferably 3 to 35 mol%, and the amount used must be set so that the silicon content contained in the obtained siloxane-modified polyimide precursor is 0.5% by weight or less. .

Unless these quantitative relationships are satisfied, it becomes difficult to achieve both adhesion and moisture resistance.

The ratio of the diamino compound consisting of diaminosiloxane and silicon-free diamine to the aromatic tetracarboxylic dianhydride is usually equimolar, but one may be slightly increased if necessary.

The polymerization reaction may be carried out according to conventionally known methods, generally in the presence of an inert solvent and in a stream of nitrogen gas, taking into account the polymerization heat generated, while limiting the temperature to usually 40° C. or lower, particularly preferably 30° C. or lower. The reaction may be carried out until a predetermined degree of polymerization is obtained.

Note that polyimide used as a protective film or an insulating film on the surface of a semiconductor element must be prevented from being contaminated with ionic impurities.

Cationic impurities such as Na+, K+, Ca++, Cl
Care must be taken to avoid contamination from anionic impurities such as -, and in particular Na+ ions have a negative effect on the electrical properties of the polyimide protective film or insulating film.

Therefore, during polymerization, both the raw material monomer and the solvent should be sufficiently purified by well-known methods before use.

For example, Na+ ion is 5PPm or less, preferably 1ppm.
The following is desirable.

Inert solvents used in such polymerization reactions include:
For example, N-methyl-2-pyrrolidone, N.N'-dimethylacetamide, N.N'-dimethylformamide,
Highly polar basic solvents such as N.N'-dimethylsulfoxide and hexamethylphosphoramide are used.

All of these types of solvents are highly hygroscopic, and absorbed water causes a decrease in molecular weight during polymerization and a decrease in storage stability, so it is best to thoroughly dehydrate with a dehydrating agent before use.

Further, general-purpose solvents such as benzonitrile, benzene, and phenol can also be used in combination.

However, the amount used should be within a range that does not reduce the solubility of the polyimide precursor produced.

The degree of polymerization of the siloxane-modified polyimide precursor synthesized by the above method can be easily detected by examining the intrinsic viscosity [η] of the reactant.
．． It is desirable that the degree of polymerization is as high as 3 to 3.0.

This is because if it is lower than this, good results will not be obtained in terms of heat resistance and other general properties.

The intrinsic viscosity [η] described in this specification is measured using N-methyl-2-pyrrolidone as a solvent and at a measurement temperature of 30
It means the value calculated according to the following formula at ±0.01°C (constant temperature bath).

t; Falling time t0 of the polymer solution collected by the Ubbelohde viscometer; Falling time C of the solvent measured in the same manner as above; Polymer concentration (assumed to be 0.5% by weight) In the second step of this invention, Following the first step, heat aging is carried out in the same reaction vessel in a nitrogen stream by raising the temperature to 40 to 80°C, preferably 50 to 60°C. The obtained siloxane-modified polyimide precursor having a high degree of polymerization is subjected to appropriate molecular cleavage or rearrangement to reduce the molecular weight.

The degree of molecular weight reduction is determined by the relationship between solution viscosity and polyimide properties, and it is generally preferable to set the intrinsic viscosity to 0.3 to 0.7.

As a guide, the solution viscosity is 1000 at a solution concentration of 25% by weight.
~20,000 centipoise.

If the above-mentioned intrinsic viscosity becomes too low, the film forming ability in the final stage will be poor, and the insulation properties, heat resistance and other properties will be impaired when applied to semiconductors.

The reason why the heat aging temperature was set at 40 to 80℃ is as follows.
This is because if the temperature exceeds 80°C, especially above 100°C, the crosslinking reaction will proceed and there is a risk of gelation.
This is because if the temperature is lower than ℃, the effect of ripening will not be sufficiently obtained, and the ripening time will become longer, impairing workability.

Even though the siloxane-modified polyimide precursor as the final product obtained in this way has a lower degree of polymerization, it is still a silicon-free diamine as shown in the following general formula (4). The bonding units of diaminosiloxane and aromatic tetracarboxylic dianhydride added to aromatic tetracarboxylic dianhydride via amide bonds have a random polymer structure, and very few siloxane bonds are incorporated into the molecular chain of this polyimide precursor. It is characterized by having a structure.

(RI, R2, R', n and Ar are both positive integers, m/l+m=0.01 to 0, as described above.
．． 04) (RI, R2, R'Ar, n, l, and m are as described above) Such a siloxane-modified polyimide precursor has a low solution viscosity, and for example, the charging concentration in the first step is ~
Even when the amount is 25% by weight or more, it has a viscosity suitable for spin coating, dipping, brushing, etc. without diluting it in each second step.

On the other hand, by coating this on an adherend such as a silicon wafer using the above coating method, and then subjecting it to high temperature heat treatment, dehydration, and cyclization, it exhibits excellent adhesion to silicon wafers, glass, etc. This polyimide can be converted into a polyimide as shown by the general formula (5), and this polyimide has excellent moisture resistance, as well as its inherent good heat resistance, chemical resistance, mechanical properties, and excellent electrical insulation properties. Equipped with:

Therefore, the siloxane-modified polyimide precursor obtained by the method of this invention has the advantage of being widely applicable to various conventionally known uses such as surface protective films and interlayer insulating films for semiconductor devices, and junction protective films for diodes.

EXAMPLES Below, examples of the present invention will be described in more detail.

Example 1 A 500 ml flask equipped with a stirrer, condenser, thermometer and nitrogen purge device was fixed on a water bath.

148.71 g of N·N'-dimethylformamide, which had been dried over calcium hydride for one day and distilled under nitrogen purging, was added to the flask, nitrogen was flushed, and the first step was carried out in the following manner.

First, bis(3-aminopropyl)tetramethyldisiloxane; H2N℃CH using a 1ml microsyringe.
2+-3Si(CH3)2-0-Si(CH3)2(C
H2) 20.87 g (0.0035 mol) of 3NH, then 19.3 g of 4,4'-diaminodiphenyl ether (
0.0965 mol) and stirred until dissolved.

Thereafter, 29.4 g (0.1 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride was gradually added.

The reaction system was stirred while maintaining the temperature below 30° C. until a transparent viscous solution was obtained.

The 25% by weight solution of the siloxane-modified polyimide precursor thus obtained has a viscosity measured with a BH type viscometer at 25°C (the same applies hereinafter), which is at least the measurement upper limit (2,000,000 centipoise), and an intrinsic viscosity of the precursor. was 1.67, and the silicon content was 0.397% by weight.

Next, in the second production step, the water bath was removed and replaced with a hot water bath, the same reaction vessel was heated to 55±5°C with stirring, heated and aged in a nitrogen stream for 6 hours, and then continued for 28 hours.
By heating and aging for a total of 34 hours, the molecular weight was reduced until the intrinsic viscosity was 0.42 and the solution viscosity was 4400 centipoise.

Spin coat this precursor solution onto a silicon wafer,
1 hour at 150℃ in a hot air dryer, 1 hour at 200℃, 2
A tough polyimide film was formed by heat treatment at 50°C for 6 hours.

The infrared absorption spectrum of this polyimide film is 1780
Absorption >C=0 due to imide group formation was observed at cm-1 and 1720 cm-1.

In addition, the above-mentioned spin coating was performed at 3500 rpm. p. This was carried out by dropping 2 to 3 g of the precursor solution at a rotational speed of m.

Example 2 The amount of purified N·N-dimethylformamide used was 125.
Polymerization reaction (first step) was carried out in the same manner as in Example 1, except that 21.8 g (0.1 mol) of pyromellitic dianhydride was used as the aromatic tetracarboxylic dianhydride.
25 of a high molecular weight siloxane-modified polyimide precursor having a silicon content of 0.469% by weight, an intrinsic viscosity of 1.65, and a solution viscosity of 2,000,000 centipoise or more.
A weight percent solution was obtained.

Next, as a second step, the above precursor solution was heated and aged at 55±5°C for 24 hours in the same manner as in Example 1 until the intrinsic viscosity was 0.38 and the solution viscosity was 2200 centipoise. The molecular weight has been reduced.

This precursor solution was spin-coated onto a silicon wafer in the same manner as in Example 1, and dried in a hot air dryer at 150°C for 1 hour.
A tough polyimide film was formed by heat treatment at 00°C for 1 hour and at 300°C for 1 hour.

Example 3 The amount of purified N・N'-dimethylformamide used was 156
．． 53g, 32.2g (0.1 mol) of 3,1,4,4'-benzophenonetetracarboxylic dianhydride as aromatic tetracarboxylic dianhydride, and 4,4' as silicon-free diamine. -diaminodiphenylmethane 19.10
The polymerization reaction (first step) was carried out in the same manner as in Example 1, except that 7 g (0.0965 mol) was used, and the silicon content was 0.377% by weight, and the intrinsic viscosity was 1.38. A 25% by weight solution of a high molecular weight siloxane-modified polyimide precursor having a solution viscosity of 1,700,000 centipoise was obtained.

Next, as a second step, the above precursor solution was heated and aged at 55±5°C for 15 hours in the same manner as in Example 1, so that the intrinsic viscosity was 0.45 and the solution viscosity was 23.
The molecular weight was reduced to 0.00 centipoise.

This precursor solution was spin-coated onto a silicon wafer in the same manner as in Example 1, and then heat-treated to form a polyimide film.

The tensile strength of this film after 6 months was 40% of the initial value.
%, but it was strong enough to be used as a protective film or an insulating film.

Comparative Example 1 The amount of purified N・N'-dimethylformamide used was 148
．． 27g, the amount of 4,4'-diaminodiphenyl ether used was 19.9g (0.0995 mol), and the amount of bis(3-aminopropyl)tetramethyldisiloxane used was 0.
．． A polymerization reaction (first step) was carried out in the same manner as in Example 1, except that the amount was 1243 g (0.0005 mol),
A 25% by weight solution of a high molecular weight siloxane-modified polyimide precursor having a silicon content of 0.057% by weight, an intrinsic viscosity of 2.37, and a solution viscosity of 2,000,000 centipoise was obtained.

Next, as a second step, the precursor solution was heated and aged in the same manner as in Example 1 to lower the molecular weight until the intrinsic viscosity was 0.41 and the solution viscosity was 2700 centipoise.

This precursor solution was spin-coated onto a silicon wafer in the same manner as in Example 1, and then heat-treated to form a polyimide film.

Comparative Example 2 The amount of purified N・N'-dimethylformamide used was 149
．． 22g, the amount of 4,4'-diaminophenyl ether used was 18.6g (0:093 mol), and the amount of bis(3-aminopropyl)tetramethyldisiloxane used was 1.7g.
The polymerization reaction (first step) was carried out in the same manner as in Example 1, except that the amount was 395 g (0.007 mol). A 25% by weight solution of a siloxane-modified polyimide precursor having a viscosity of 50,000 centipoise was obtained.

Next, as a second step, the above precursor solution was heated and aged in the same manner as in Example 1 to lower the molecular weight until the intrinsic viscosity was 0.45 and the solution viscosity was 5100 centipoise.

This precursor solution was coated on a silicon wafer in the same manner as in Example 1, and then heated to form a polyimide film.

Comparative Example 3 Bis(3-aminopropyl)tetramethyldisiloxane and 4,4'-diaminodiphenyl ether were prepared in Example 2.
After carrying out a polymerization reaction with pyromellitic dianhydride separately in the same proportion as , the two were mixed to obtain a 25% by weight solution of a polyimide precursor mixture.

The intrinsic viscosity of the polyimide precursor obtained from diaminosiloxane was 0.63, and the intrinsic viscosity of the polyimide precursor obtained from silicon-free diamine was 2.00.

Also, the silicon content in the polyimide precursor mixture is 0.46
At 9% by weight, the solution viscosity was above the measurement upper limit (2,000,000 centipoise).

Next, the above solution was further heated and aged in the same manner as in Example 1 to lower the molecular weight until the intrinsic viscosity was 0.53 and the solution viscosity was 4100 centipoise.

This precursor solution was spin-coated in the same manner as in Example 2, and then heat-treated in the same manner to form a polyimide film.

Comparative Example 4 The amount of purified N·N'-dimethylformamide used was 99.9%.
27 g, 21.8 g (0.1 mol) of pyromellitic dianhydride as the aromatic tetracarboxylic dianhydride, and 10 g of paraphenylene diamine as the silicon-free diamine.
．． Polymerization reaction (first Step) was carried out to obtain a silicon content of 0.594% by weight and an intrinsic viscosity of 1.
58, a 25% by weight solution of a siloxane-modified polyimide precursor having a solution viscosity of 1,800,000 centipoise was obtained.

Next, as a second step, the above precursor solution was heated and aged in the same manner as in Example 1 to lower the molecular weight until the intrinsic viscosity was 0.39 and the solution viscosity was 1900 centipoise.

This precursor solution was spin-coated onto a silicon wafer in the same manner as in Example 1, and then further heat-treated to form a polyimide film.

Next, the polyimide films obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were tested for adhesion and electrical insulation under the same environmental conditions.

Furthermore, the coatability (state of the coating film) by spin coating when forming the polyimide film was visually observed.

These results were as shown in the following table.

Note that A in Examples 1 to 3 is the result of each example, and B is the high molecular weight and high molecular weight obtained in the first step, with the second step omitted in each example for reference. These are test results when a polyimide film was formed by diluting a viscous siloxane-modified polyimide precursor solution with a solvent to the extent that it could be coated.

As is clear from the above table, according to the solution of the siloxane-modified polyimide precursor produced by the present invention,
It has excellent applicability to device surfaces such as silicon wafers and glass, can overcome defects caused by coating defects such as cracks and pinholes, and has excellent adhesion, heat resistance, low stress, mechanical strength, and moisture resistance. It can be seen that a polyimide film with excellent properties can be formed, contributing to stable supply of semiconductor devices and improved reliability.

It is also clear that in Example 1, in which 33',4,4'-biphenyltetracarboxylic dianhydride was used as the aromatic tetracarboxylic dianhydride in this invention, the effect was particularly remarkable. It is.

On the other hand, unlike this invention, in the case where heat treatment is not performed during the polymerization reaction (B in each example), the coating properties are poor, and in the case where the amount of diaminosiloxane used is small (comparative example 1), (Comparative Examples 2 and 4)
In this case, the adhesion may be impaired or the moisture resistance properties may be deteriorated, and furthermore, even if the amount of diaminosiloxane used is within the range of this invention, diaminosiloxane and silicon-free diamine must be separately mixed with aromatic tetracarboxylic dianhydride. It can also be seen that when the reaction method is adopted (Comparative Example 3), good results are not obtained in terms of adhesion, moisture resistance, etc.

As another experiment, a siloxane-modified polyimide precursor having an intrinsic viscosity of 0.75 and a solution viscosity of 30,000 centipoise was prepared by changing the heat treatment time in the second step in Example 1 to 6 hours, and using this, the same procedure as above was performed. When a polyimide film was formed, the properties of the film during spin coating were improved to some extent, but some thickness unevenness was observed, and the coating properties were inferior to those of Example 1.

Conversely, when the heat treatment time was 60 hours, the intrinsic viscosity was 0.
28. When a siloxane-modified polyimide precursor with a solution viscosity of 600 centipoise was made and a polyimide film was formed using it, microcracks were generated in the film because the molecular weight was too low, and the dielectric breakdown voltage decreased.
The performance as a semiconductor surface protective film or an insulating film could not be demonstrated.

Claims (1)

[Claims] 1 In an inert solvent, represented by the following general formula: (RI is a divalent organic group, R is a monovalent organic group, and n is an integer from 1 to 1000) Polymerizing a diamino compound consisting of diaminosiloxane and a diamine that does not contain a silicon atom in the molecule with an aromatic tetracarboxylic dianhydride in a proportion such that the diaminosiloxane accounts for 1 to 4 mol% of the total amount of the diamino compound. The first step is to obtain a solution of a siloxane-modified polyimide precursor having a silicon content of 0.5% by weight or less, and after this step, the above solution is heated and aged at 40 to 80°C to determine the intrinsic viscosity of the precursor. A method for producing a siloxane-modified polyimide precursor that can be converted into a polyimide with good adhesiveness and moisture resistance. 2 The intrinsic viscosity of the siloxane-modified polyimide precursor in the first step is in the range of 1.3 to 3.0, and the intrinsic viscosity of the siloxane-modified polyimide precursor in the second step is 0.
．． A method for producing a siloxane-modified polyimide precursor according to claim 1, wherein the siloxane-modified polyimide precursor has a molecular weight in the range of 3 to 0.7. 3 As aromatic tetracarboxylic dianhydride, 3.3'
- A method for producing a siloxane-modified polyimide precursor according to claim 1 or 2, which uses 4,4'-biphenyltetracarboxylic dianhydride.