JPH0560500B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a polyimide composition, and more particularly to a polyimide composition capable of obtaining a polyimide having a low Young's modulus. [Prior Art] In recent years, in the semiconductor industry, the integration of semiconductor elements has progressed rapidly, and in the DRAM field, 4M bit level products are being prototyped. However, with this increase in integration, the problem of thermal stress caused by the difference in linear expansion coefficient between the silicon substrate and the resin encapsulant increases, causing cracks in the passivation film and breakage of the aluminum wiring. A strange situation is occurring. Unless these problems are resolved, products with stable quality cannot be obtained. Therefore,
It is desired to develop a heat-resistant resin coating agent with a low Young's modulus to weaken thermal stress, but in the case of conventional polyimide, the Young's modulus is at least 250.
The actual situation is that there are kg/ ^mm2 . In view of these circumstances, the inventors of the present invention have conducted intensive studies on measures to reduce the Young's modulus of polyimide, and have found that:
The present invention was achieved based on the finding that when a polyimide composition is composed of two specific polyimide precursors, a polyimide having a significantly low Young's modulus and excellent strength and elongation properties can be obtained. [Problems to be Solved by the Invention] Therefore, an object of the present invention is to achieve a low Young's modulus,
Another object of the present invention is to provide a polyimide composition from which a polyimide having excellent strength and elongation can be obtained. [Means for Solving the Problems] The object of the present invention is to provide a polyimide precursor A obtained by reacting 4,4'-bis(aminophenoxy)diphenyl and pyromellitic anhydride;
Polyimide precursor B obtained by reacting 4'-diaminodiphenyl ether and pyromellitic anhydride
and the polyimide precursor A
This is achieved by a polyimide composition in which B and B are blended in a molar ratio of A/B = 5/95 to 95/5. The polyimide precursor A in the present invention comprises 4,
4'-bis(aminophenoxy)diphenyl (hereinafter
BAPOD) and pyromellitic anhydride (hereinafter referred to as BAPOD) and pyromellitic anhydride (hereinafter referred to as
Polyimide precursor B is obtained by reacting 4,4'-diaminodiphenyl ether (hereinafter referred to as DAE).
It is obtained by reacting PMDA. The polyimide composition of the present invention contains the polyimide precursors A and B as described above, and
The precursors A and B have a molar ratio of A/B=5/
It is formulated to have a ratio of 95 to 95/5. The molar ratio of polyimide precursor A to B is
If the molar ratio is more than 95/5, the polyimide precursor varnish tends to gel, resulting in poor storage stability, which is undesirable. If the molar ratio is less than 5/95, a product with a low Young's modulus cannot be obtained. A particularly preferred range is 1/9 to 4/1. The polyimide composition of the present invention can contain other diamines and tetracarboxylic acids as long as they do not affect the Young's modulus. Examples of such diamines include m-phenylenediamine,
3,3'-diaminodiphenylmethane, 3,3'-diaminodiphenyl sulfone, benzidine, 4,
Examples include aromatic diamines such as 4'-diaminoterphenyl and 1,3-bis(aminophenoxy)benzene, and aliphatic diamines such as hexamethylene diamine and heptamethylene diamine. Examples of tetracarboxylic acids include 3, 3', 4,
4'-Benzophenonetetracarboxylic acid, 3,3',
4,4'-biphenyltetracarboxylic acid, 3,3'4,
Aromatic carboxylic acids such as 4'-diphenyl ether tetracarboxylic acid, aliphatic tetracarboxylic acids such as 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid Examples include acids. In order to further improve the adhesion, a siloxane diamine such as 1,3-bis(3-aminopropyl)tetramethyldisiloxane) may be added in an amount of 1 to 6 mol % based on the total amount of amines. Next, an example of a method for producing the polyimide composition of the present invention will be explained. That is, the molar ratio of PMDA to BAPOD in the solvent is preferably 90 to 110 mol%.
The polyimide precursor A of the present invention is produced by reacting at -20°C to 100°C at a blending ratio of: In addition, the molar ratio of PMDA to DAE in a solvent is preferably 90 to 110 mol%, and
The polyimide precursor B of the present invention is produced by reacting at °C. Polyimide precursor A produced as above
and polyimide precursor B in a molar ratio of 5/95~
A precursor of the polyimide composition of the present invention can be obtained by mixing in a ratio of 95/5. As the solvent used in the above production method, it is preferable to use a polar solvent from the viewpoint of solubility of the polymer, and an aprotic polar solvent is particularly preferable.
As the aprontic polar solvent, N-methyl-2
-pyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide, hexamethylphosphorotriamide, dimethyl sulfoxide, γ-
Butyrolactone and the like are preferably used. Next, the varnish of the polyimide precursor obtained as described above is applied onto a suitable support, and heated at 50 to 100°C.
to obtain a polyimide precursor film. A polyimide film is obtained by chemically or thermally treating the polyimide precursor film thus obtained to undergo dehydration and ring closure. In the case of chemical treatment, a polyimide film is obtained by immersing a polyimide precursor film in a mixed solution of acetic anhydride and pyridine. In addition, when thermally processing the polyimide precursor film, the temperature can be increased stepwise by selecting several temperatures in the range from room temperature to 450°C, or by selecting a certain temperature range and increasing the temperature continuously. It is recommended that the treatment be carried out for 5 minutes to 5 hours. For example, 130℃, 200℃, 300℃, 400℃
Heat treatment for 30 minutes each, or from room temperature
The temperature may be increased linearly to 400°C over 2 hours. (Method for measuring properties) Young's modulus The method for measuring Young's modulus of the present invention is as follows:
Based on Z1702, a test piece with a sample width of 10 mm and a test length of 50 mm was prepared using a Tensilon manufactured by Toyo Baldwin Co., Ltd. for 20 minutes.
Measurements were made at a tensile rate of mm/min. At the same time, strength and elongation were determined. Moisture-resistant adhesion A cutter is used to make 25 cuts in the polyimide film formed on a silicon wafer at 2 mm intervals, 6 in length and width, creating 25 grids. This is heated to 120℃.
Humid heat treatment is performed for a predetermined period of time under saturated steam at 2.0 atm. Attach cellophane adhesive tape (manufactured by Nichiban Co., Ltd.) to this sample and apply JIS D 0202 Table 13, 1.
Peel off according to the method described in . Viscosity: Using a Tokyo Seimitsu E-type rotational viscometer, measure 1 ml of the polyimide precursor solution with a syringe and heat to 25°C.
The viscosity was measured. [Examples] The present invention will be specifically described below based on Examples. Examples 1 to 3, Comparative Examples 1 and 2 102.2 g of PMDA and 184.2 g of BAPOD were added to 1450 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP).
The reaction was carried out at 30°C for 1 hour and then at 70°C for 2 hours to obtain a polymer solution (1) (polyimide precursor A) having a viscosity of 100 poise. In addition, PMDA 104.7g and DAE 100.1g were added to NMP.
A polymer solution (2) with a viscosity of 30 poise obtained by reacting 1182.1 g at 30°C for 1 hour and then at 70°C for 2 hours
(Polyimide precursor B) was obtained. Polymer solutions (1) and (2) created as above
were mixed in the proportions shown in Table 1 to obtain a polyimide precursor solution. For each of the obtained polyimide precursor solutions, the initial viscosity and the change in viscosity after being left at 25° C. for one week were investigated and shown in Table 1. Next, the mixed solution of the polyimide precursor described above was applied onto a silicon wafer using a spinner so that the thickness after imidization was 20μ±2μ. this
A polyimide film was prepared by heat treatment at 80°C, 200°C, 300°C, and 350°C for 30 minutes each, and its Young's modulus was measured as shown in Table 1. In Table 1, Examples 1 to 3 are polyimide compositions in which polyimide precursor A and precursor B of the present invention are mixed, Comparative Example 1 is a polyimide made only of polyimide precursor A, and Comparative Example 2 is a polyimide composition made of polyimide precursor A. This is the case of polyimide consisting only of body B. As is clear from Table 1, in the case of polyimide made only of polyimide precursor A, the varnish of the precursor was unstable and gelled after 16 hours at 5°C. Further, in the case of polyimide made only of polyimide precursor B, there is a drawback that Young's modulus is high. On the other hand, the film made of the polyimide composition of the present invention has a low Young's modulus and excellent strength and elongation properties. Furthermore, the storage stability of the polyimide precursor varnish was good, and it was stable at 5° C. for more than one month. Example 4 PMDA 102.2g, BAPOD 176.8g, 1,3-
5.0 g of bis(3-aminopropyl)tetramethyldisiloxane was dissolved in 1350 g of NMP at 30°C for 1 hour.
Subsequently, a reaction was carried out at 70°C for 2 hours to obtain a polymer solution (3) with a viscosity of 80 poise. Polymer solution (3) prepared as above was added to 8
parts by weight, and 2 parts by weight of polymer solution (2) were mixed and stirred.
A mixed solution of 50 poise was obtained. Next, the obtained polyimide precursor mixed solution was applied onto a silicon wafer using a spinner so that the thickness after imidization was 20μ±2μ,
Heat treatment was performed at 80°C for 1 hour, at 200°C and 300°C for 30 minutes each, and further at 350°C for 1 hour. This film has a Young's modulus of 200Kg/mm ² and a strength of 10
It showed good properties with Kg/mm ² and elongation of 30%. In addition, the mixed solution of the obtained polyimide precursor was
When the viscosity change was examined after being left at 25°C for one week, the viscosity after one week was 62 poise, which was a good value with no major change observed. Comparative Example 3 10.91g of PMDA, 16.26g of 2,2-bis(4-(4-aminophenoxy)phenyl)propane
The reaction was carried out in 150 g of NMP at 30°C for 1 hour and then at 70°C for 3 hours to obtain a polymer solution (4) with a viscosity of 100 poise. Polymer solution (4) and polymer solution (1) prepared as described above were mixed at a ratio of 2:1 and stirred to obtain a mixed solution with a viscosity of 100 poise. Next, the obtained mixed solution was applied onto a silicon wafer in the same manner as in Example 1 and imidized to form a polyimide film, and the Young's modulus was measured. The Young's modulus of the obtained film was 240Kg/mm ² ,
Although the strength was 14 Kg/mm ² and the elongation was 40%, which were relatively good, the polymer solution gelled when left at 25° C. for one week, making it unsuitable for use. [Effect of the invention] As described above, the polyimide composition of the present invention has 2
By blending a specific type of polyimide precursor in a specific ratio, it was possible to obtain a highly functional polyimide with a low Young's modulus and excellent strength and elongation. Further, the polyimide composition of the present invention has remarkable practical effects such as good storage stability of the polyimide precursor varnish (the varnish shows little change in viscosity over time and is less likely to gel). 【table】

Claims (1)

[Claims] 1 Polyimide precursor A obtained by reacting 4,4'-bis(aminophenoxy)diphenyl with pyromellitic anhydride, and polyimide precursor B obtained by reacting 4,4'-diaminodiphenyl ether with pyromellitic anhydride. consisting of a mixture of
and a polyimide composition in which the polyimide precursors A and B are blended in a molar ratio of A/B = 5/95 to 95/5.