JPS599107B2 - bubble memory chip - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in bubble memory chips.

Conventionally, as shown in Figure 1, the method for manufacturing bubble memory chips involves first using non-magnetic GGG (gadolinium, gallium,
garnet) A magnetic garnet crystal 2 is formed on a substrate 1 using a liquid phase growth method, and further, a spacer (silicon oxide (SiO2)) 3, a conductor pattern (Al-Cu) 4,
A second spacer (silicon oxide (SiO2)) 5 is laminated in this order.

These patterns and films can be created by sputtering, vapor deposition,
It is formed using an etching method or the like. Next, a driving pattern (permalloy) 6 is formed on the spacer 5 by vapor deposition and etching, and a protective film T (silicon oxide (SiO2), alumina (Al2O3),
Silicon nitride (Si3N4) or the like is manufactured using a sputtering method or a CVD method.

Therefore, the drive pattern (permalloy) 6 is protected by the insulating layer of the protective film T for protecting it from scratches, rust, etc. caused by external conditions. By the way, the insulating material of this protective film T (silicon oxide (SiO2), alumina (Al2O3), silicon nitride (
The process of forming Si3N4), etc.) to a thickness of several μm or more by sputtering requires a long time of 6 to 8 hours to process several dozen sheets, and is not suitable for mass production.

As a solution to this problem, drive pattern (permalloy) 6
If a polyimide resin is used as the upper protective film T and is spin-coated, the time will be significantly reduced compared to the above, mass productivity will be improved, and the insulating layer of the protective film T can also be formed with a thickness of several μm or more.

However, since heat treatment at 350° C. (160 minutes) is required when curing the polyimide resin, the portion of the polyimide resin A at the edge of the drive pattern (permalloy) 6 is thermally decomposed and becomes brittle, as shown in FIG. , the magnetic properties of the drive pattern (permalloy) 6 also deteriorate. In order to eliminate the above-mentioned drawbacks, the present invention aims to form a chip having a protective film that can be mass-produced without impairing the mechanical strength and magnetic properties of the drive pattern. and a bubble memory chip comprising a protective film for protecting the driving pattern, wherein the protective film includes a first protective film made of an inorganic insulating layer formed on the driving pattern; A second layer consisting of an organic insulating layer formed on the film
An object of the present invention is to produce a bubble memory chip characterized by comprising a protective film and a protective film.

The present invention will be explained in detail below using the drawings. FIG. 2 shows a side sectional view of the bubble memory chip of the present invention. As shown in the figure, in the method for manufacturing a bubble memory chip of the present invention, first, a magnetic garnet crystal 2 is grown on a non-magnetic GGG substrate 1 using a liquid phase growth method, and a spacer (silicon oxide ( SiO2))3, conductor pattern (A1-
Cu) 4, second spacer (silicon oxide (SiO2)) 5
, are formed in this order using a sputtering method, vapor deposition, etc., and a driving pattern (permalloy) 6 is formed thereon.

The steps up to this point are the same as conventional ones. On top of this, a first protective film 7 made of an inorganic insulator such as silicon oxide, alumina, or silicon nitride is formed by a sputtering method over a period of approximately 80 minutes, and an organic insulating material such as polyimide resin is further applied thereon by a spin coating method. The second protective film 8 is formed by heat treatment at 350° C. for 60 minutes.

In this way, the first protective film 7 is protected by the second protective film 8, so it can be thin and the processing time is shortened. , a brittle portion of the drive pattern (permalloy) edge (portion A in FIG. 1) does not occur, and deterioration of the magnetic properties of the drive pattern 6 can also be prevented.

As explained above, this chip uses insulating materials (silicon oxide (SiO2), alumina (AI2O2),
3) By providing the first protective film 7 made of silicon nitride (SiN3, etc.) and the second protective film 8 made of special resin (polyimide resin, etc.), the thermal decomposition caused by heat treatment and the magnetic properties of permalloy etc. Deterioration, etc. can be prevented, processing time is shortened, mass productivity is improved, and a thick protective film can be formed on the drive pattern (permalloy), which has remarkable effects.

In the above description, polyimide resin was used as an example, but the present invention is of course not limited to this, and other organic insulators may be used.

[Brief explanation of drawings]

FIG. 1 is an enlarged front sectional view of a bubble memory chip formed by a conventional method, and FIG. 2 is an enlarged front sectional view of essential parts of an embodiment of the bubble memory chip of the present invention. In the figure, 1...GGG board, 2...
...Garnet, 3,5...Spacer, 4
. . . Conductor pattern, 6 . . . Drive pattern, 7, 8 .

Claims (1)

[Claims] 1. In a bubble memory chip comprising a driving pattern on a magnetic bubble crystal and a protective film for protecting the driving pattern, the protective film is a first protective layer made of an inorganic insulating layer formed on the driving pattern. 1. A bubble memory chip comprising: a film; and a second protective film made of an organic insulating layer formed on the first protective film.