JPS6152554B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble memory device, and more particularly to an improvement in the cross-sectional structure of a magnetic bubble memory device.

FIG. 1 is a diagram illustrating a main part of an example of a magnetic bubble memory element. In the figure, m is a minor loop that stores information, RML is a read mager line that transfers read information, and WML is a write mager line that transfers write information. Also,
D is a bubble detector that converts magnetic bubbles into electrical signals, G is a bubble generator that generates magnetic bubbles, and R
is the major line that reads information about minor loop m.
A replicate gate circuit for copying or transferring to RML, T is a transfer gate circuit for transferring information on the light mager line WML to the minor loop m. Furthermore, the GR surrounding these outer peripheries is a guardrail that prevents magnetic bubbles from entering from the outer periphery, and the BP is a bonding pad.

Further, FIG. 2 is an enlarged plan view of a main part showing an example of the pattern of the transfer gate circuit T shown in FIG. 1. In the figure, reference numeral 10 indicates a magnetic bubble transfer circuit such as the read mager line RML, write mager line WML, and minor loop m by arranging fine patterns formed of a thin film of soft ferromagnetic material such as permalloy in a predetermined shape. 20 is a transfer circuit element, for example, Al-Cu, Au-
It is a hairpin-shaped conductor loop formed of a non-magnetic conductor thin film such as Mo, through which an operating current for controlling the magnetic bubble flows, and 30 is a magnetic bubble medium.

Further, FIG. 3 is a diagram showing an example of the cross-sectional layer structure of the pattern constituting the magnetic bubble memory element. In the same figure, 10 is the above-mentioned transfer circuit element;
20 is a conductor loop, 30 is a magnetic bubble medium, 40 is a spacer, 41 is an insulating film, and 42 is a protective film, which are formed of a SiO ₂ film, an Al ₂ O ₃ film, or the like. The film thicknesses of the above-mentioned layers that are generally used are as follows. That is, the thickness of the spacer 40 is 1000 Å to 4000 Å, the thickness of the insulating film 41 is 1500 Å to 6000 Å, and the thickness of the conductor 20 is 1000 Å to 4000 Å.
The film thickness of the transfer circuit element 10 is 3000 Å to 5000 Å, and the film thickness of the transfer circuit element 10 is 3000 Å to 4500 Å. In this case, the reason why each film thickness has a width is because the size of the magnetic bubble used, that is, the diameter d has a width.
It is 4 μm, and generally, as the diameter d becomes smaller, the thickness of each film also becomes thinner.

However, the magnetic bubble memory element with the above configuration has two major problems as shown below. That is, one of the problems is caused by the fact that the distance between the magnetic bubble medium 30 and the transfer circuit element 10 (hereinafter referred to as spacing) differs depending on the location. That is, as shown in FIG. 3, the spacing of the transfer circuit element 10 located above the conductor loop 20 is smaller than the spacing of the transfer circuit element 10 that is not located above the conductor pattern 20. 2
It is increased by the film thickness of 0. Generally, different spacings of transfer circuits result in different characteristics of the transfer circuits transferring magnetic bubbles. That is, if the spacing differs, the stable operating region of the transfer circuit changes. As a result, these two common stable operating regions become narrower. Another problem is caused by a boundary portion D where the transfer circuit element 10 extends from a place where the conductor loop 20 does not exist to a place where the conductor loop 20 does exist, as shown in FIG. It is. That is, this boundary portion D is a portion where the spacing of the transfer circuit element 10 changes rapidly (hereinafter referred to as a stepped portion), and generally the transfer circuit element 10 has such a stepped portion D. If there is, the magnetic bubble transfer characteristics will be significantly deteriorated in this part, and the stable operation area of the transfer circuit will be narrowed.

Therefore, in an effort to solve the above-mentioned conventional problems, the inventors have filed a patent application for the following magnetic bubble memory element. That is, in the same layer as the layer forming the conductor loop 20 through which the operating current flows, conductor patterns for spacers are arranged at various locations of the magnetic bubble memory element, in addition to the conductor loop 20. FIG. 4 is an enlarged plan view of essential parts showing an example of the case where this pending application is applied to the transfer gate circuit T described in FIG.
Since the same symbols as those in the figure represent the same elements, their explanation will be omitted. In FIG. 4, 20 is a conductor loop through which an operating current flows, and 20' is a conductor pattern for the spacer. The conductor loop 20 and the spacer conductor pattern 20' are electrically insulated by an insulating band 200 provided along the contour of the conductor loop 20. Note that the width g of this insulating band 200 is 1 to
It is about 2 μm. In this case, the entire surface of the magnetic bubble memory element, except for the insulating band 200, is covered with the conductor loop 20 or the spacer conductor pattern 20'. As a result, the spacing of all the transfer circuit pieces 10 becomes uniform without varying depending on the location. In other words, the first problem mentioned above can be solved.

However, as can be easily seen from FIG.
A stepped portion D as shown in the figure is generated, and the second problem mentioned above is still unsolved. That is, in FIG. 5, the same symbols as those in FIG. 3 are the same elements, so the explanation thereof will be omitted. Here, 20 is a conductor loop, 20' is a conductor pattern for a spacer, and the distance g between the conductor loop 20 and the conductor pattern 20' is 1 to 2 μm.
It is electrically insulated by an insulating band 200.
The transfer circuit element 10 on this V-shaped insulating band 200 has a step D as shown.

Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional magnetic bubble memory element, so that the spacing of the transfer circuit element is uniform regardless of the location, and furthermore, the transfer circuit element has a stepped portion. The object of the present invention is to provide a magnetic bubble memory device with no magnetic bubbles.

In order to achieve this purpose, the magnetic bubble memory device according to the present invention includes a spacer conductor pattern that is electrically insulated with an insulating band along the contour of the conductor loop, in addition to the conductor loop that supplies the operating current. In addition, a polyimide resin such as PIQ (polyimide isoindroquinadrine dione) is used as an insulating layer. The magnetic bubble memory device according to the present invention will be described in detail below with reference to the drawings.

FIG. 6 is a cross-sectional structural view of essential parts showing an example of the magnetic bubble memory element according to the present invention, and since the same symbols as those in FIG. 5 represent the same elements, a description thereof will be omitted. In the figure, 20 is a conductor loop through which an operating current flows, and 20' is a spacer conductor pattern. 200 is an insulating band provided along the contour of the conductor loop 20, electrically insulating the conductor loop 20 and the spacer conductor pattern 20'. 10 is a magnetic bubble transfer circuit element. 41' is an insulating layer made of PIQ, and this insulating layer 41' made of PIQ is used to connect the conductor loop 20 and the spacer conductor pattern 2.
It is interposed between the layer 0' and the layer of the transfer circuit element 10. In other words, the material of this insulating layer 41' was SiO ₂ or Al ₂ O ₃ in the conventional case, but in the present invention, it is made of polyimide resin, such as PIQ.
It is distinctive in that it uses Here, this
PIQ, as is well known, is an organic material called polyimide, isoindro, quinadrine, and dione.It is a viscous substance before use, and has the property of solidifying after use, and has already been used as an insulating film in fields such as semiconductors. It's being used.

In the magnetic bubble memory element configured in this way, if a polyimide resin such as PIQ is used as the insulating layer 41' between the conductor loop 20, the layer of the spacer conductor pattern 20', and the layer of the transfer circuit element 10, the conductor loop The insulating band 200 between the layer 20 and the spacer conductor pattern 20' is filled flat with the viscosity of the polyimide resin, and the insulating layer 41' is formed as shown in FIG.
The top surface of is a flat surface. Here, when the width g of the insulating band 200 is as small as 1 to 2 μm, the upper surface of the insulating layer 41' becomes almost completely flat, but on the other hand, when the width g is as large as 5 μm or more, polyimide Even if the system resin has viscosity, it is not possible to fill 200 parts of the insulating band flatly, and therefore the insulating layer 41'
The top surface is also not flat. However, in the magnetic bubble memory device according to the present invention, since the width g of the insulating band 200 is 1 to 2 μm, the upper surface of the insulating layer 41' is flat, as shown in FIG. As a result, the 10 layers of transfer circuit elements formed on the insulating layer 41' become flat as shown in FIG.
The step D described in FIG. 5 no longer occurs on the insulating band 200. Further, the spacing of the transfer circuit element 10 is also uniform regardless of the location.

As explained above, according to the magnetic bubble memory device according to the present invention, the spacing of the transfer circuit pieces is uniform regardless of the location, and there is no step part in the transfer circuit pieces, so that the transfer characteristics of the magnetic bubble can be improved. It is possible to obtain extremely excellent effects such as increasing the stability of the transfer circuit and widening the stable operation area of the transfer circuit.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of main parts showing an example of a magnetic bubble memory element, FIG. 2 is a plan view of main parts showing a pattern of a gate circuit, and FIG. 3 is a cross-sectional layer structure diagram of FIG. 2.
FIG. 4 is a plan view of a main part showing a pattern of a gate circuit, FIG. 5 is a cross-sectional layer structure diagram of FIG. 4, and FIG. 6 is a cross-sectional layer structure diagram showing an example of a magnetic bubble memory element according to the present invention. DESCRIPTION OF SYMBOLS 10... Transfer circuit element, 20... Conductor loop, 20'... Conductor pattern for spacer, 30... Magnetic bubble medium, 40... Spacer, 41... Insulating film, 41'... Insulating layer, 42...
...Protective film, 200...Insulating band.

Claims (1)

[Claims] 1. A transfer circuit element layer forming a transfer circuit for transferring magnetic bubbles, a conductor loop layer through which an operating current flows to control the magnetic bubbles, and an insulating layer interposed between the two layers. In the magnetic bubble memory element having a multilayer laminated structure, a conductor pattern for a spacer is provided in the same layer as the conductor loop layer and electrically insulated via an insulating band along the outline of the conductor loop layer,
A magnetic bubble memory element characterized in that the insulating layer is made of polyimide resin. 2. The magnetic bubble memory element according to claim 1, wherein PIQ is used as the polyimide resin.