JPS6048063B2 - magnetic bubble device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble device, particularly a connecting terminal portion of a conductor pattern or a permalloy pattern thereof, and an object of the present invention is to improve the wire bonding strength at the terminal portion.

Fig. 1 is a conceptual diagram of the terminal section of a conventional magnetic bubble chip, Fig. 2 is a cross-sectional view showing the state of the same magnetic bubble chip after packaging, and Fig. 3 is a cross-sectional view of the pattern section of a conventional magnetic bubble chip. It is.

1 is Gadakudanium, Gallium, Garnet (G・G
-G) A magnetic thin film such as a magnetic garnet film formed by liquid phase epitaxial (LPE) method on the substrate 1', which generates and maintains the under-valve main.

An insulator layer 2 such as 5102 is formed on this magnetic film 1,
A conductor pattern made of Al--Cu or the like is formed thereon to form a main control circuit under the valve. Further, on this conductive pattern 3, an insulating layer 4 similar to that described above is formed, and a magnetic material pattern such as permalloy is formed thereon to transfer and detect the valve domain. Functional patterns such as the conductor pattern 3 for control and the permalloy pattern 5 for transfer and the respective terminal parts 3' and 5' are created in the same process, but the conductor pattern contains 3000 pieces and the permalloy pattern contains 4 pieces.
Since the thickness is as thin as 0.008 mm, it is not thick enough to be used as a connecting terminal portion, causing problems. That is, as shown in FIG. 2, the lead wire 6 is ultrasonically bonded to the terminal portions 3' and 5' of the valve chip 10, and the other end of the wire is bonded to the Au plating pattern 8 on the ceramic substrate 7.
After coating with resin 9 or the like, the coating film 9 is heat-treated. The coating film expands and contracts during heat treatment, but
At this time, stress is applied between the wire 6 and the terminal portions 3', 5', and since the terminal portions 3', 5' are thin, there is a problem of wire breakage at the bonding portion. In the case of ICs, etc., this problem is rare because the pattern thickness is sufficiently thick at around 1 μm, but in the case of magnetic bubble elements, when the conductor pattern 3 is made thicker, a step is created in the permalloy pattern 5, which reduces the characteristics. Therefore, as mentioned above, the limit is about 3000Λ. If the permalloy pattern is made too thick, it will be difficult to generate magnetic poles, so the maximum thickness is about 4000 mm, which is not sufficient for a connection terminal portion. Of course, it is possible to deposit only the terminal portion thickly, but this increases the number of manufacturing steps and increases the cost of the product. Also, JP-A-51-11
As described in Japanese Patent No. 4833, it has been proposed to thicken the bonding terminal portion by further laminating a conductor such as aluminum in a separate process. However, in this case, the conductor layer to be laminated later is created in a separate process from the lamination process of the conductor pattern, transfer pattern, and the like. Therefore, it is not an effective means to increase the number of pattern forming steps just for the bonding terminal portion, which increases the cost. The present invention solves these conventional problems and realizes a magnetic bubble device that can increase the thickness of the connection terminal part to the extent that disconnection does not occur at the wire bonding part without increasing the manufacturing process. The purpose is to

In order to achieve this object, the present invention provides that, when forming the conductor pattern, a terminal pattern for the permalloy pattern is also formed at the same time, and when forming the permalloy pattern, the terminal pattern formed of the conductor pattern material is A terminal pattern made of permalloy is superimposed on the conductor pattern and the terminal pattern is formed so that the thickness of the terminal portion is equal to the thickness of the conductor pattern and the permalloy pattern. Next, examples of the present invention will be described in detail.

FIG. 4 is a diagram showing a method of manufacturing a magnetic bubble device according to the present invention, and FIG. 5 is a perspective view of a wire-bonded magnetic bubble device. To manufacture the magnetic hub 3 device of the present invention, a conductor pattern 3 and its terminal pattern 3'' are required.
At the same time, a terminal pattern 31 for the permalloy pattern is also created at the position where the terminal pattern of the permalloy pattern is to be created. These patterns can be patterned in the same process using the same mask 3.
Next, an insulating layer 4 is formed. In this case, the terminal patterns 3'' and 31 are exposed so as not to be covered with the insulating layer 4. On this insulating layer 4, a permalloy pattern 5 is formed. However, in this case as well, the edge 4ζ child pattern is
It is formed not only on the permalloy pattern side but also on the conductor pattern side. That is, on top of the terminal pattern 31 made of Ni-Cu material, the terminal pattern 5 of the permalloy pattern is placed.
2 is laminated, and a permalloy layer 51 is also laminated on the terminal pattern 3'' for conductor pattern.Therefore, in the terminal pattern part, the lower layer is A1- of the conductor pattern material.
The upper Cul layer has a two-layer structure of permalloy, and only the terminal portion has the thickness of the J conductor pattern + the thickness of the permalloy pattern, resulting in a thick film thickness of about 0.7 μm. FIG. 5 shows a state in which the A1 lead wire 6 is bonded onto the terminal pattern of the laminated structure, and the other end is bonded onto the Au plating pattern 8 of the ceramic substrate 7. After this, a coating film 9 is applied and heat treatment is performed. do.

A tensile strength of about 3y is required to prevent wire breakage at the bonding portion of the lead wire due to expansion and contraction of the coating film during heat treatment. FIG. 6 is a graph showing the tensile strength of the wire bonding portion. The intensity distribution when A1 wire is bonded onto permalloy or A1-Cu as in the past shows a peak at about 3y, and there are also quite a few cases below 3y. However, when wire bonding is performed on a laminated terminal of A1-Cu and permalloy as in the present invention, the peak value is 4.5 f.
Most of them show an intensity of 3y or higher. For this reason, as in the present invention, when forming two or more types of patterns, only the connection terminal part is always formed and laminated at each patterning time, and if the film thickness is increased, the strength of the wire bonding part is increased. The coating film is improved to the extent that it can sufficiently withstand expansion and contraction of the coating film, eliminating conventional concerns and improving product yield. In particular, when the metals laminated on each other are N-Cu and Permalloy as in this embodiment, the adhesion is good and this is very effective in terms of strength.

Moreover, since the connection terminal portions are also patterned at the same time as the conductor pattern or permalloy pattern is patterned, there is no need for additional steps and there is no risk of increased costs.

The illustrated example is a conductor-first type in which the conductor pattern 3 is provided on the bubble magnetic film 1 side, but the permalloy-first type in which the permalloy pattern 2 is provided on the double bubble magnetic film side is implemented. However, you can get the same great effect.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the pattern of a conventional magnetic bubble chip, Fig. 2 is a sectional view showing the state of the same magnetic bubble chip after packaging, and Fig. 3 is a pattern of a conventional magnetic bubble chip. FIG.

Claims (1)

[Claims] 1 A magnetic bubble having at least two types of functional patterns, a conductor and a magnetic material, which are patterned in separate processes, and each functional pattern and its terminal pattern are patterned at the same time, and which are not formed in the patterning process in the previous process. on a terminal pattern made of either a conductor or a magnetic material.
During the patterning process in the post-process, a terminal pattern consisting of the other conductor or magnetic material is formed by overlapping the other, and the connection terminal part of each functional pattern is patterned in both the pre-process and the post-process, thereby creating a laminated structure of the conductor and the magnetic material. A magnetic bubble device comprising: