JPH11176997A - Glass mold semiconductor device coating glass slurry - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of an electric characteristic owing to winding foam, by adding aliphatic alcohol in glass mold semiconductor coating glass slurry constituted of glass powder and water. SOLUTION: Used glass powder is not regulated if it can be used for glass mold semiconductor element coating, and it is effective especially in the case of zinc glass. It is desirable to use more than one or two types of added aliphatic alcohol whose number of carbons is 1 to 3. When alcohol whose number of carbons is not less than four is used, the winding of slurry and smoothness on the surface after drying cannot be obtained and it becomes a cause of unstable form after burning. It is desirable that added quantity of aliphatic alcohol is 0.1 to 5 weight % against 100 weight % glass powder. When it is less than 0.1 weight %, effect for improving wettability with the semiconductor device is small. When it is more than 5 weight %, the winding of slurry and smoothness on the surface after drying are difficult to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass slurry used for coating a glass mold type semiconductor device.

[0002]

2. Description of the Related Art Heretofore, a so-called glass-molded semiconductor has been known in which a semiconductor element such as a silicon diode having a PN junction is entirely covered with glass to stabilize the surface of the element and hermetically seal the element. This semiconductor is manufactured by adding a suitable amount of pure water to zinc-based or lead-based glass powder, dropping and winding a glass slurry on a semiconductor element and an electrode in a rotating state, followed by drying and firing. Is done.

[0003]

Since the interface between the semiconductor element and the electrode has a step and is not flat, bubbles (voids) are liable to be involved when the slurry is wound. Since most of the entrained bubbles are in contact with the surface of the semiconductor element, the surface stabilization and hermetic sealing, which are the original purposes of the coating glass, are insufficient, and the electrical characteristics of the semiconductor element are deteriorated, particularly, the reverse withstand voltage. And the reverse leakage current increases.

[0004] It is an object of the present invention to provide a glass slurry for coating a glass mold type semiconductor element which does not deteriorate the electric characteristics due to entrained bubbles.

[0005]

The glass slurry for coating a glass mold type semiconductor element of the present invention is obtained by adding an aliphatic alcohol to a glass slurry for coating a glass mold type semiconductor element comprising glass powder and water. Features.

[0006]

The glass slurry of the present invention improves the wettability with a semiconductor element by adding an aliphatic alcohol.
Foam entrapment is reduced. In addition, since the slurry easily flows between the element surface and the bubbles, and the bubbles hardly come into contact with the element surface, deterioration of the electrical characteristics of the semiconductor element can be prevented.

The glass powder used in the present invention is:
There is no particular limitation as long as it can be used for coating a glass mold type semiconductor element, but it is particularly effective in the case of zinc-based glass. The zinc-based glass, for example, 45 to 75% ZnO by weight percent, B ₂ O ₃ 15~30%,
_{SiO 2 5~15%, PbO 1~10%} , MnO 2
_{0~5%, Bi 2 O 3 0~20} %, Nb 2 O 5 0
_{~5%, Sb 2 O 3 0~4} %, Al 2 O 3 0~5%,
TiO ₂ 0 to 3%, the glass having a composition of CeO ₂ 0 to 2% may be used. As the lead-based glass, for example, 30 to 70% by weight of PbO, 25% by weight of SiO _{2
~60%, B 2 O 3 0~20} %, Al 2 O 3 0~1
Glass having a composition of 0% can be used.

As the aliphatic alcohol to be added in the present invention, it is preferable to use one or more of aliphatic alcohols having 1 to 3 carbon atoms, specifically, methyl alcohol, ethyl alcohol, isopropyl alcohol and the like. Can be used. The reason for limiting the number of carbon atoms of the aliphatic alcohol to 1 to 3 is that if an alcohol having 4 or more carbon atoms is used, the slurry is not wound, and the smoothness of the surface after drying is not obtained. That's why.

The amount of the aliphatic alcohol to be added is preferably 0.1 to 5 parts by weight based on 100 parts by weight of the glass powder. The reason for limiting the addition amount in this manner is that if it is less than 0.1 part by weight, the effect of improving the wettability with the semiconductor element is small, and if it is more than 5 parts by weight, the slurry is wound and the surface smoothness after drying is reduced. This is because it is difficult to obtain.

In the present invention, pure water is desirably used as the water added to make the glass powder into a slurry, and the amount of addition is 25 to 45 parts by weight based on 100 parts by weight of the glass powder. Appropriate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

Tables 1 and 2 show examples of the present invention (sample N
o. 1 to 6) and a comparative example (sample No. 7).

[0013]

[Table 1]

[0014]

[Table 2]

Sample No. 1 to 6 were prepared as follows.

First, a zinc-based glass (Z
_{nO 60%, B 2 O 3} 25%, SiO 2 10%,
_{PbO 2%, Bi 2 O 3} 1%, Nb 2 O 5 1%,
Sb ₂ O ₃ 1%) and lead glass (PbO 45%,
SiO ₂ 40%, B ₂ O ₃ 10%, Al ₂ O ₃ 5
%) Were prepared. In addition, each glass powder was produced so that an average particle diameter might be set to 4 micrometers.

Next, 35 parts by weight of pure water was added to 100 parts by weight of the glass powder, and an aliphatic alcohol having 1 to 3 carbon atoms was further added and kneaded to obtain a slurry to obtain a sample. In addition, the kind of glass powder, the kind and addition amount of aliphatic alcohol were as shown in the table.

Sample No. 7 was produced in the same manner as described above except that no aliphatic alcohol was added.

Next, each sample was dropped and wound around a rotating semiconductor element, dried, and fired at 680 ° C.
Subsequently, after polishing the glass covering the semiconductor element to expose the element surface, the polished surface was observed with a stereoscopic microscope,
The total number of bubbles, the number of bubbles in contact with the element surface, and the distance of bubbles not in contact with the element from the element surface were measured. The results are shown in the table.

As is clear from the table, Sample No. to which no aliphatic alcohol was added was used. Sample No. 7 had 24 bubbles, of which 17 were in contact with the element surface. The distance of bubbles not in contact with the element from the element surface is 50 μm at the shortest.
Met. On the other hand, in the embodiment of the present invention, No. 1
The samples No. to No. 6 have 12 to 15 bubbles and the sample Nos. 7, and the number of bubbles in contact with the element surface was sharply reduced to 6 or less. The distance of the bubbles not in contact with the element from the element surface was 110 μm or more. It was found that the slurry was more likely to flow between the element and the foam than in Example 7, and the contact between the two was hard to occur.

[0021]

As described above, when the glass slurry of the present invention is used, the entrapment of bubbles generated during the winding of the slurry can be reduced, and the contact of the bubbles with the element surface can be suppressed. is there. Therefore, deterioration of the electrical characteristics of the semiconductor element can be prevented, and it is suitable as a glass slurry used for coating a glass mold type semiconductor element.

Claims (3)

[Claims] 1. A glass slurry for coating a glass mold type semiconductor element, comprising: a glass slurry for coating a glass mold type semiconductor element comprising glass powder and water, wherein an aliphatic alcohol is added. 2. The glass slurry for coating a glass mold type semiconductor element according to claim 1, wherein an aliphatic alcohol having 1 to 3 carbon atoms is used. 3. The method according to claim 1, wherein water is 25 to 45 parts by weight and aliphatic alcohol having 1 to 3 carbon atoms is 0.1 to 5 parts by weight based on 100 parts by weight of the glass powder. Glass mold type glass slurry for semiconductor element coating.