JPH08119671A - Treatment of powdery glass - Google Patents

Abstract

PURPOSE: To provide a method for treating powdery glass by which a hardly separable slurry having high viscosity can be prepd. while using lead-contg. powdery glass. CONSTITUTION: The surface of lead-contg. powdery glass is treated with an aq. HNO3 soln. This soln. is preferably added by 0.03-1 pt.wt. per 100 pts.wt. of the powdery glass and the pref. concn. of the soln. is 0.1-15wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating powder glass, and more particularly to a method for treating powder glass for coating a semiconductor used for the purpose of protecting a PN junction of a semiconductor.

[0002]

2. Description of the Related Art Conventionally, a so-called glass mold type semiconductor in which the entire semiconductor element such as a silicon diode having a PN junction is covered with glass is a slurry prepared by adding an appropriate amount of pure water to zinc-based or lead-based powder glass. And is applied to a semiconductor element and fired.

By the way, the powdered glass used for such purposes has a low slurry viscosity when made into a slurry, or has a problem in workability in a coating process when water and glass are separated from each other, resulting in electrical characteristics of a semiconductor. Cause deterioration of the yield and a decrease in yield such as defective shape. Therefore, there is a demand for powdered glass that has a high viscosity and is capable of producing a slurry that is difficult to separate.

[0004]

Generally, powdered glass is
It is produced by crushing a lump-shaped or plate-shaped glass molded product in a crushing device such as a ball mill using pure water as a crushing aid and classifying.

However, among the powdered glass produced by such a method, particularly lead-based powdered glass has a problem that a sufficiently high viscosity cannot be obtained when it is made into a slurry, and separation easily occurs. It is difficult to meet the demands made.

It is an object of the present invention to provide a method for treating powdered glass which is a lead-based powdered glass and which has a high viscosity and is difficult to separate.

[0007]

As a result of a detailed study, the present inventors have found that the above object can be achieved by treating the surface of powder glass with an HNO ₃ aqueous solution, and propose the present invention. Is.

That is, the method for treating powder glass of the present invention is as follows:
It is characterized in that the surface of powdered glass is treated with an HNO ₃ aqueous solution.

As a treatment method, a method of adding an HNO ₃ aqueous solution as a grinding aid at the time of producing powder glass, that is, at the time of grinding is preferable because it is efficient.
In addition to this, a method may be used in which HNO ₃ aqueous solution is added after being made into powder glass and uniformly stirred and mixed by using a ball mill or the like.

In the present invention, the powder glass to be treated may be either zinc-based or lead-based glass, but it is particularly effective in the case of lead-based glass. For example, P in terms of weight percentage.
bO 30 to 70%, SiO ₂ 25 to 60%, B ₂ O ₃ 0
20%, the glass having a Al ₂ O ₃ 0% of the composition can be used.

The amount of HNO ₃ aqueous solution added as a treatment liquid is 0.03 with respect to 100 parts by weight of powdered glass.
It is preferably from 1 to 1 part by weight, and the concentration is 0.1.
It is desirable to be 1 to 15% by weight. The reason for limiting the addition amount and concentration in this way is as follows. If the addition amount is less than 0.03 part by weight, the effect is small. If it exceeds 1 part by weight, the pulverizability and the classifying property are deteriorated when it is treated at the same time as the pulverization, and the glass properties are locally deteriorated and the fluidity of the powder itself is lowered when it is treated after the pulverization. Are likely to deteriorate. If the concentration of the HNO ₃ aqueous solution is less than 0.1% by weight, its effect is small, while if it exceeds 15% by weight, problems tend to occur in terms of safety and workability.

[0012]

When the surface of the powder glass is treated with the HNO ₃ aqueous solution, the surface of the powder is etched to increase the surface area.
Also, the powder particles become loosely entangled with each other,
It becomes easy to disperse. Therefore, when the slurry is used, the viscosity of the slurry is higher than that of the untreated product, and it becomes difficult to separate the slurry.

[0013]

EXAMPLES The method for treating powdered glass of the present invention will be described below based on examples.

[0014]

[Table 1]

Table 1 shows Examples (Sample Nos. 1 to 5) and Comparative Examples (Sample No. 6) treated by the method of the present invention.

Each sample was processed as follows.

First, glass raw materials prepared so as to have the compositions shown in the table were melted and then formed into a film. Next, this molded product was crushed in a ball mill with the addition of the grinding aid shown in the table to obtain powder glass having an average particle size of about 4 μm.

Next, 30 parts by weight of pure water was added to 100 parts by weight of each sample obtained and kneaded to prepare a slurry, and the viscosity, the presence or absence of separation, and the applicability to a semiconductor element were evaluated. The results are shown in the table.

As can be seen from the table, No. 1 treated by the method of the present invention. Each of the samples 1 to 6 has a slurry viscosity of 150.
It was 0 to 2000 cp, and separation of powder glass was not observed. Moreover, these samples were excellent in coating property.

On the other hand, sample No. which is a comparative example. 6
Had a low slurry viscosity of 500 cp and separation was observed. Moreover, the coatability was poor.

The slurry viscosity is measured by using a rotary viscometer.
The measurement was carried out under the conditions of 25 ° C. and 10 rpm. Regarding the presence / absence of separation, after leaving the prepared slurry for 1 hour, the powder glass was not separated, and the powder glass was confirmed to be separated. The applicability was evaluated as follows. First, the semiconductor element was rotated in the axial direction, and the slurry was dropped onto the semiconductor element and applied by winding the slurry. Then, at this time, it is possible to apply and the molded glass has a uniform shape as shown in FIG. 1, it is not possible to apply, or even if application is possible, the shape is not uniform as shown in FIG. I made something impossible. 1 and 2, reference numeral 10 denotes a semiconductor element composed of the Cu lead 11, Mo electrode 12 and silicon semiconductor chip 13, and 20 denotes molded glass.

[0022]

The powder glass treated by the method of the present invention has a high viscosity and is capable of producing a slurry which is difficult to separate. Therefore, it is particularly suitable as a method for treating lead-based powder glass used for coating glass mold type semiconductors.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a state in which a semiconductor element is uniformly molded with glass.

FIG. 2 is an explanatory diagram showing a state in which a semiconductor element is non-uniformly molded with glass.

[Explanation of symbols]

 10 semiconductor element 20 glass

Claims (5)

[Claims] 1. A method for treating powder glass, which comprises treating the surface of the powder glass with an HNO ₃ aqueous solution. 2. A powder glass 1 containing an HNO ₃ aqueous solution in an added amount.
The method for treating powder glass according to claim 1, wherein the amount is 0.03 to 1 part by weight with respect to 00 parts by weight. 3. The method for treating powder glass according to claim 1, wherein the concentration of the HNO ₃ aqueous solution is 0.1 to 15% by weight. 4. The method for producing powdered glass according to claim 1, wherein the powdered glass is lead-based glass. 5. Powder glass containing PbO 30 in weight percentage.
_{~70%, SiO 2 25~60%,} B 2 O 3 0~20
%, Al ₂ O ₃ 0-10% composition.