JPH09193149A - Production of tablet of molding material for sealing semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the productivity of a tablet by preventing a molding material for sealing a semiconductor from adhering to the upper and rear surfaces of a punch when the molding material is continuously molded into a tablet shape. SOLUTION: When a molding material for sealing a semiconductor is molded into a tablet shape by a continuous tablet molding machine, a carboxy modified dimethylsiloxane layer is applied to the upper and rear surfaces of a punch in a thickness of 0.5-50μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for tableting a molding material for semiconductor encapsulation, and a manufacturing method for improving releasability at the time of taking out a tablet after tableting. It is about.

[0002]

2. Description of the Related Art In a molding material for semiconductor encapsulation, it is required to improve the adhesion strength with a metal in order to improve the adhesion with a frame. Further, in order to prevent the occurrence of voids in the package after semiconductor encapsulation, it is desired to increase the density of tablets, and it has become necessary to increase the molding pressure when tableting. Along with these demands, there has been a problem that a part of the molding material adheres to the punch surface after molding during tablet manufacturing, and a part of the tablet surface is missing. In order to prevent the adhesion, various methods such as a method of adding a minute amount of a releasing agent such as a higher fatty acid metal salt for tableting and a method of baking and coating the releasing agent on the punch surface have been studied, but sufficient effects have not been obtained. I haven't got it yet. Therefore, when adhesion occurs, the tablet tableting machine is stopped to clean the punch surface to remove the adhered matter, but the productivity is remarkably reduced.

[0003]

The present invention has been made as a result of various studies in order to solve the problem of the adhesion of the molding material to the punch surface. The purpose of the present invention is to make a tablet at the time of tableting. It is to improve productivity by eliminating adhesion to the punch surface.

[0004]

[Means for Solving the Problems] In order to solve such problems, as a study for preventing the adhesion of the molding material to the punch surface, the punching is performed while cooling the punch below the softening temperature of the material. Adhesion occurred after about 2,000 shots, and conversely, when tableting was performed by heating the punch to about 40 ° C., not only adhesion occurred from about 100 shots, but also melting of the material. The viscosity in the state increased and a problem in terms of quality occurred. Next, an attempt was made to perform baking coating with a fluorine-based release agent on the punch surface.
Adhesion occurred after about a shot. JP-A-7-11704
The method disclosed in Japanese Patent No. 8 describes a method for preventing sticking by injecting air to the upper and lower punch surfaces. However, when tableting is performed by a continuous tablet molding machine, 2,0
Adhesion occurred at about 00 shots, and the effect was insufficient. Further, the method of adding a release agent such as a higher fatty acid metal salt to the material in advance by several wt% has a large effect of preventing adhesion, but results in a decrease in the reliability of the material.

As a result of these studies, as a result of earnestly studying a method of keeping a minute amount of a release agent which does not affect the quality of the material, on the punch surface at the time of tableting, the carboxyl-modified dimethylpolysiloxane was studied. It was found that it is very effective to coat the above with 0.5 to 50 μm, preferably 1 to 20 μm, and then to coat into a tablet. That is, according to the present invention, when the molding material for semiconductor encapsulation is tablet-molded by a continuous tablet molding machine, the upper and lower punch surfaces are coated with carboxyl-modified dimethylpolysiloxane so that the layer thickness becomes 0.5 to 50 μm. A method for producing a tablet of a molding material for semiconductor encapsulation, the method comprising tableting.

With respect to the mold release agent, various mold release agents were tested, but the carboxyl-modified dimethylpolysiloxane shown below is excellent in that it has the effect of preventing adhesion of the molding material and hardly affecting the quality. The result was obtained. The thickness of the coating layer at this time is 0.5 to
It is 50 μm, preferably 1 to 20 μm. If the coating layer is thinner than 0.5 μm, there is no effect of preventing adhesion, and if it is thicker than 50 μm, the adhesion strength with the frame after semiconductor encapsulation is reduced, which adversely affects the quality of the material itself. * Carboxyl-modified dimethylpolysiloxane _{(CH 3) 3 SiO - [} (CH 3) 2 SiO] l - [CH 3 SiOC n H 2n COOH] m -Si (CH
₃ ) ₃ (However, l = 3 to 5, m = 150 to 170, n = 8 to 12)

[0007]

【Example】

Example 1 3 parts by weight of carboxyl-modified dimethylpolysiloxane and 97 parts by weight of n-pentane were mixed and stirred to prepare a uniform solution. While spray-coating this solution on the upper and lower punch surfaces with an average thickness of 3 μm, 100,000 tablets were tableted with a continuous tablet tableting machine, and as a result, adhesion to the punch surfaces did not occur. In the practical test, there was no problem, and the spray coating did not adversely affect the quality.

Comparative Example 1 3 parts by weight of alkyl silicone oil and 97 parts by weight of n-pentane were mixed and stirred to prepare a uniform solution. Tableting was performed while spray-coating this solution in the same manner as in Example 1, but 2,000
The molding material adhered to the punch surface with 0 shots, and some of the tablets were missing. <Comparative Example 2> Tableting was performed in the same manner as in Example 1 except that the surface of the upper and lower punches was baked and coated with a fluorine-based release agent, and spraying was not performed using this punch. After 10,000 shots, the molding material adhered to the punch surface, and some of the tablets were missing.

Comparative Example 3 Tableting was performed in the same manner as in Example 1 while spray-coating the solution used in Example 1 to an average thickness of 0.3 μm, but 1,000 shots were taken on the punch surface. Some molding materials adhered and some tablets were missing. << Comparative Example 4 >> The solution used in Example 1 was prepared to have an average thickness of 70 μm.
As a result of performing 100,000 tableting in the same manner as in Example 1 while spray-coating with No. 1, adhesion to the punch surface did not occur, but in the practical test, the adhesion strength with the frame was weak and peeling occurred. It was

[0010]

According to the method of the present invention, it is possible to prevent the molding material from adhering to the punch surface during tableting of the molding material for semiconductor encapsulation, and to significantly improve the productivity of tablets. Therefore, the same quality as the conventional one can be obtained, which is suitable as a method for industrially manufacturing a tablet of a molding material for semiconductor encapsulation.

Claims (1)

[Claims] 1. When tableting molding of a molding compound for semiconductor encapsulation with a continuous tablet molding machine, carboxyl-modified dimethylpolysiloxane is coated on the upper and lower punch surfaces so that the layer thickness is 0.5 to 50 μm. A method for producing a tablet of a molding material for semiconductor encapsulation, which comprises tableting.