JP2621180B2 - Polyimide composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyimide composition, and more particularly, to a polyimide composition from which a polyimide having a low Young's modulus can be obtained.

[Prior Art] In recent years, in the semiconductor industry, integration of semiconductor elements has been rapidly progressing, and in the field of DRAM, 4 Mbit level products have been prototyped. However, the problem of thermal stress due to the difference in the coefficient of linear expansion between the silicon substrate and the resin encapsulant increases with the increase in the degree of integration, and cracks occur in the passivation film and aluminum wiring is cut. Things are happening. Unless these problems can be solved, a product with stable quality cannot be obtained. Therefore, although the development of a resin coating agent having heat resistance at a low Young's modulus in order to weaken the thermal stress is desired, actual situation in the conventional polyimide, because the Young's modulus is 250 kg / mm ² at a minimum It is.

In view of such circumstances, the present inventors have conducted intensive studies on measures to lower the Young's modulus of polyimide, and as a result, the polyimide composition is composed of a mixture of siloxane diamine having a specific structure, aromatic diamine and acid anhydride. If you do
The present inventors have found that a polyimide having a remarkably low Young's modulus and excellent in strong elongation properties and moisture resistance can be obtained, and the present invention has been achieved.

[Problems to be Solved by the Invention] Accordingly, an object of the present invention is to provide a polyimide composition that can obtain a polyimide having a low Young's modulus and excellent strength, elongation, and moisture resistance.

[Means for Solving the Problems] An object of the present invention is to provide a polyimide composition comprising a polyimide precursor and a solvent, wherein the polyimide precursor is represented by the following formulas (I), (II) and (III). (III) / ((I) + (II) + (III)) = 5 / 1000-10 / 100 (II) / (I) = 5 / 95-95 / 5 A polyimide composition obtained by reacting a raw material diamine with pyromellitic dianhydride.

(Wherein X is -O- or -S-, Y is -O-, -S
-, - SO -, - SO 2 -, - CO -, - CH 2 -, - CF 2 -, - C
Cl ₂ −, R is an alkylene group having 1 to 20 carbon atoms, a fluorinated alkylene group or a phenylene group, R 'is an alkyl group having 1 to 10 carbon atoms, a fluorinated alkyl group or a phenyl group, and n is an integer of 3 to 20. ) X is selected from -O- or -S-. Y is -O-, -S-, -SO-,-
SO _2- , -CO-, -CH _2- , -CF _2- , -CCl _2- , Selected from such, more preferably -O -, - S- or -CF ₂ - and although not limited thereto. R is carbon number 1
To 20 alkylene groups, fluorinated alkylene groups or phenylene groups, more preferably methylene, propylene, hexafluoropropylene and phenylene groups. R 'represents an alkyl group having 1 to 10 carbon atoms, a fluorinated alkyl group or a phenyl group, more preferably a methyl group, a trifluoromethyl group and a phenyl group. n is an integer of 3 to 20, more preferably 8 to 14.

Such a polyimide precursor contains, in a raw material diamine component, the above three kinds of diamine components in a molar ratio of (III) / ((I) + (II) + (III)) = 5/1000 to 10/100 ( II) / (I) = 5/95 to 95/5, and obtained by reacting this mixture with pyromellitic dianhydride.

Here, (III) / ((I) + (II) + (III)) is 5 /
If it is less than 1000, you will not get a low Young's modulus,
If it exceeds 10/100, you will not be able to obtain a transparent one and lose practicality. When (II) / (I) is more than 95/5, the varnish becomes unstable and gels easily and loses practicality. More preferably, Range.

The polyimide composition of the present invention can be modified with another diamine or tetracarboxylic acid as long as it does not affect the Young's modulus. Examples of such diamines include:
Aromas such as phenylenediamine, toluenediamine, 3,3'-diaminodiphenylsulfone, benzidine, 3,4'-diaminodiphenylmethane, dimethylbenzidine, chlorbenzidine, diaminoterphenyl, bis (aminophenoxy) benzene, diaminoanthraquinone Aliphatic diamines such as aliphatic diamine, ethylenediamine, diaminopropane, hexamethylenediamine and heptamethylenediamine. Examples of tetracarboxylic acids include aromatic tetracarboxylic acids such as benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid, and diphenylethertetracarboxylic acid, and aliphatic tetracarboxylic acids such as butanetetracarboxylic acid and cyclopentanetetracarboxylic acid. Is mentioned.

In order to further improve the adhesiveness, a siloxane diamine such as 1,3-bis (3-aminopropyl) tetramethyldisiloxane is blended in an amount of 1 to 6 mol% of the total amine amount,
It can also be denatured.

Next, an example of the method for producing the polyimide composition of the present invention will be described. That is, three kinds of diamines (I), (II) and (III) are contained in a solvent in a molar ratio, By reacting with preferably 90 to 110 mol%, more preferably equimolar pyromellitic dianhydride with respect to the total diamine amount at -20 ° C to 100 ° C, A varnish of the polyimide precursor of the present invention can be obtained.

As the solvent used in the above production method, it is preferable to use a polar solvent from the viewpoint of the solubility of the polymer, and particularly preferable is an aprotic polar solvent. Examples of aprotic polar solvents include N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, hexamethylphosphorotriamide, dimethylsulfoxide, γ
-Butyrolactone, sulfolane and the like are preferably used.

Further, an aromatic hydrocarbon such as toluene or xylene may be mixed with the above-mentioned polar solvent and used.

Next, the varnish of the polyimide precursor obtained as described above is applied on a suitable support, and dried at 50 to 100 ° C. to obtain a polyimide precursor film.

The polyimide precursor film thus obtained is chemically or thermally treated and subjected to dehydration and ring closure to obtain a polyimide film.

When chemically treating, a polyimide film is obtained by immersing the polyimide precursor film in a mixed solution of acetic anhydride and pyridine. In the case of thermal treatment, the film of the polyimide precursor is heated from room temperature to 45 ° C.
Select a temperature in several steps within the range of 0 ° C and raise the temperature step by step,
It is preferred to carry out for 5 minutes to 5 hours while selecting a certain temperature range and continuously raising the temperature. For example, 130 ° C, 200 ° C, 300 ° C, 4
Heat treatment at 00 ℃ for 30 minutes each, or from room temperature to 400 ℃
Up to 2 hours.

(Method of measuring properties) Young's modulus The method for measuring the Young's modulus of the present invention was based on JIS-Z1702, and a test piece having a sample width of 10 mm and a test length of 50 mm was measured at a tensile speed of 20 mm / min using Tensilon manufactured by Toyo Baldwin. .
At the same time, strength and elongation were calculated.

Moisture Resistance Adhesion Cuts are made on the polyimide film formed on the silicon wafer with a cutter at intervals of 2 mm by 6 in the vertical and horizontal directions to make 25 grids. At 120 ° C under 2.0 atm of saturated steam,
The wet heat treatment is performed for a predetermined time. A cellophane adhesive tape (Nichiban Co., Ltd.) was attached to this sample, and JIS D0202 table
Peel off according to the method described in 13,1.

[Examples] Hereinafter, the present invention will be specifically described based on examples. However, the amino group equivalent refers to the molecular weight per amino group.

Examples 1 to 3 and Comparative Examples 1 to 3 A four-necked flask having a thermometer, a stirrer, and a nitrogen inlet was charged with the acid anhydride and the diamine shown in Table 1, and N-methyl-2-pyrrolidone (hereinafter referred to as N-methyl-2-pyrrolidone) was added. The reaction was carried out so that the solid content was 20% in a mixed solvent in which the weight ratio of NMP and xylene was 6: 4. The reaction was performed in a water bath for the first 30 minutes and then at room temperature for about 5 hours to obtain a varnish of a polyimide precursor having the composition shown in Table 1. When the viscosity increased significantly after the completion of the reaction, the mixture was appropriately diluted with NMP.

The resulting varnish was applied on a silicon wafer using a spinner so that the thickness after imidization became 20 μ ± 2 μ. This was heat-treated at 80 ° C., 200 ° C., 300 ° C., and 350 ° C. for 30 minutes each to obtain a polyimide film, and the Young's modulus was measured.

As is evident from Table 1, in the case of a film made of the polyimide composition satisfying the present invention, the film has a low Young's modulus and good moisture resistance and high elongation characteristics. On the other hand, films made of the polyimide compositions of Comparative Examples 1 and 2 not containing the diamine component (III) do not show a decrease in Young's modulus, and have the disadvantages of extremely poor moisture-resistant adhesiveness, and In the case of Comparative Example 3 which did not contain the diamine component (II), the film was remarkably devitrified, and only those having no practical use were obtained.

Example 4 In the same four-necked flask as in Example 1, 52.5 g of 4,4'-bisaminophenoxydiphenyl, 66.6 g of 4,4'-diaminodiphenyl ether, 4.97 g of 1,3-bisaminopropyltetramethyldisiloxane And R = (III)
_{CH 2 3, R '= -} CH _3, and amino value is 620 (n is approximately 14.4) silicon diamine 6.2g pyromellitic dianhydride 109.1g and N- methyl-2-pyrrolidone and xylene weight ratio of The reaction was carried out in a solvent having a solid content of 6/4 (solid content concentration 16%). The reaction was carried out in a water bath for the first 30 minutes and then at room temperature for about 5 hours.

The resulting varnish was applied on a silicon wafer using a spinner so that the thickness after imidization became 20 μ ± 2 μ. This was heat-treated at 80 ° C., 200 ° C., 300 ° C., and 350 ° C. for 30 minutes each to obtain a polyimide film, and the Young's modulus was measured.

This film has a Young's modulus of 160 kg / mm ² ,
Time, strength 12 kg / mm ² and elongation 30% showed good properties.

[Effect of the Invention] Since the polyimide composition of the present invention is composed of three kinds of specific diamines as described above, it is possible to obtain a high-performance polyimide having a low Young's modulus and excellent moisture resistance, strength, and elongation. Was made.

Claims (1)

(57) [Claims] 1. A polyimide composition comprising a polyimide precursor and a solvent, wherein the polyimide precursor has a molar ratio of diamine components represented by the following formulas (I), (II) and (III): (III) / ((I) + (II) + (III)) = 5 / 1000-10 / 100 (II) / (I) = 5 / 95-95 / 5 Reaction of starting diamine with pyromellitic dianhydride What is claimed is: 1. A polyimide composition, comprising: (Wherein X is -O- or -S-, Y is -O-, -S
-, - SO -, - SO 2 -, - CO -, - CH 2 -, - CF 2 -, - C
Cl ₂ −, R is an alkylene group having 1 to 20 carbon atoms, a fluorinated alkylene group or a phenylene group, R 'is an alkyl group having 1 to 10 carbon atoms, a fluorinated alkyl group or a phenyl group, and n is an integer of 3 to 20. )