JPH0674151B2 - Molding method of glass target for magnetic head - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a glass target used for sputtering or the like.

2. Description of the Related Art With the progress of thinning technology in recent years, various oxides have come to be used as sputter targets. Glass is one of them, and a sputter method is used to form an adhesive layer having a predetermined film thickness when bonding ceramics, ferrite and the like. In particular, with the recent increase in density of magnetic recording, the gap of the magnetic head has become submicron, and in order to accurately form such a narrow gap, a glass film by sputtering has become important as a gap material. .

Conventionally, a glass target was manufactured by pouring molten glass into a mold such as cast iron or stainless steel and allowing it to cool, but it was often difficult to release the mold because it cracked during manufacture and seized with the substrate. In order to prevent this, a method of preheating the substrate or applying oil or fat on the mold is used.
Nevertheless, seizure still occurred, oil and fat volatilized when the glass was poured and mixed into the glass to form bubbles, and carbides of oil and fat contaminate the glass. Such bubbles in the glass caused cracking of the target during sputtering. Further, the impurities deteriorate the quality of the glass film formed by sputtering, making it impossible to form a highly accurate gap.

Further, the obtained glass remained strained during cooling, so that the target was rapidly cracked due to a rapid temperature rise applied during sputtering.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention solves the above problems by using a substrate having good releasability from glass, preheating this to an appropriate temperature, and performing post-treatment at an appropriate temperature. It is something to solve.

Means for Solving the Problems The present invention uses a boron nitride plate, a metal plate coated with boron nitride, or a metal plate coated with a fluororesin as a substrate having good releasability from glass, It is characterized in that this is preheated to the slow cooling temperature of the glass and that the obtained target is post-treated at a temperature of the softening temperature or higher.

Working According to the method of the present invention, it is possible to easily obtain a glass target free from bubbles and contamination without cracking or burning during manufacturing.

Example Hereinafter, an example of the present invention and a conventional example will be compared and described.
The present invention will be described by taking as an example the production of a target having a diameter of 100 mm.

Example 1 An example of producing a Pyrex (Corning No. 7740) glass target will be described.

Boron nitride substrate preheated to the gradual cooling temperature (about 560 ° C) of glass (eg, manufactured by Denki Kagaku Kogyo Co., Ltd., product number N-1, size 15)
A stainless steel ring having an inner diameter of 100 mm was placed on (0 × 150 × 10 mm), Pyrex glass was melted at 1500 ° C. in a platinum crucible, cooled to 1100 to 1200 ° C., poured into the ring, and left to stand. The obtained target was placed in an electric furnace together with the substrate, heated from 560 ° C to a softening temperature or higher (for example, 850 ° C) over 1 hour, kept at 850 ° C for 1 hour, and then left to cool in the electric furnace. The target thus obtained did not stick to the substrate, contained no bubbles or impurities in the glass, and did not crack during sputtering.

Example 2 A substrate coated with boron nitride was manufactured as follows.
One side of a stainless steel plate having a size of 150 × 150 × 10 mm was degreased, sandblasted, sprayed with boron coating S (produced by Denki Kagaku Kogyo KK), and baked at 800 ° C. for 20 minutes. A target was obtained in the same manner as in Example 1 except that this substrate was used. The properties of the obtained target are shown in Example 1.
Was similar to.

(Example 3) An example of producing a glass for sealing ferrite (No.8463, Corning) will be described.

A substrate coated with a fluororesin was produced as follows.
One side of a stainless steel plate having a size of 150 × 150 × 10 mm was degreased, sandblasted, then sprayed with fluororesin coating D-1 (manufactured by Daikin Industries, Ltd.) and baked at 380 ° C. for 20 minutes.

Place a stainless steel ring with an inner diameter of 100 mm on the substrate preheated to the gradual cooling temperature of glass (about 320 ℃), melt the glass in a platinum crucible at 900 ℃, cool to 500 ~ 600 ℃, and put in the ring. It was poured and left. The obtained target was placed in an electric furnace together with the substrate, heated from 320 ° C. to a softening temperature or higher (for example, 400 ° C.) in half an hour, kept at 400 ° C. for 1 hour, and then left to cool in the electric furnace. The target thus obtained had excellent releasability from the substrate, contained no bubbles or impurities in the glass, and did not crack during sputtering.

(Conventional Example 1) In Example 1, a stainless steel plate was used as a substrate without preheating. When glass was poured over this, the substrate and the glass partially burned, and the non-baked portion was quickly cooled, so the target was cracked irregularly.

(Conventional Example 2) In Example 1, a stainless steel plate coated with mineral oil was used as a substrate after preheating to 560 ° C. When glass was poured on this, mineral oil burned and bubbles and carbides were mixed in the glass. In addition, seizure of the substrate and glass also occurred, and the target was broken.

(Conventional Example 3) In Example 1, glass was poured into the ring, preheating was stopped, and the glass was allowed to cool. Since the target thus obtained had some distortion due to the difference in cooling rate between the surface and the substrate contact surface, cracking occurred during sputtering.

(Prior Art Example 4) In Example 1, the temperature of the base material is not more than the slow cooling temperature (for example,
It was used after preheating at 350 ° C. This result was similar to that of Conventional Example 1.

(Conventional Example 5) In Example 1, when the post-treatment temperature was lower than the softening temperature of glass (for example, 700 ° C.), the result was the same as that in Conventional Example 3.

EFFECTS OF THE INVENTION As described above, according to the method of the present invention, it is possible to easily obtain a glass target free from bubbles and contamination without cracking or burning during fabrication, and to eliminate cracking during sputtering. it can.

Claims (3)

[Claims] 1. A glass molded body is obtained by casting molten glass on a substrate of any one of a boron nitride plate, a metal plate coated with boron nitride, and a metal plate coated with fluororesin. Method for forming a glass target for a magnetic head. 2. The method of molding a glass target for a magnetic head according to claim 1, wherein the substrate is preheated to a glass annealing temperature. 3. The method for molding a glass target for a magnetic head according to claim 1 or 2, wherein the glass molded body is post-treated at a temperature of a softening temperature or higher.