JPS61250888A - Magnetic bubble memory - Google Patents

Abstract

PURPOSE:To decrease the number of components and assembling man-hours, to improve the productivity and reliability and to attain miniaturization and thin profile by forming a bias magnetic coil as a pattern to the surrounding of a magnetic bubble memory element of a flexible substrate on which the magnetic bubble memory element is mounted. CONSTITUTION:A bias coil is formed as a pattern at the surrounding of an element protection part mounted with two chips CHI on the flexible substrate. That is, a copper thin film is formed on a base film 7 via an adhesives 8, the film is etched into a prescribed pattern form to form a coil wiring lead 9h, and a wiring lead 9a or the like. Further, the 2nd base film 7a is arranged via the adhesives 8 and a copper thin film is formed on it via the adhesives 8 and etched into a loop pattern form to form patterns for a coil winding 9f and a coil lead 9g. Further, both ends of the coil winding 9f are connected to the coil wiring lead 9h with a through hole while penetrating the film 7a, a cover film 10 is adhered to the upper face of them via the adhesives 8 to form a BIC.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic bubble memory, and particularly to a magnetic bubble memory suitable for reduction in thickness, size, and power consumption.

[Background of the invention]

Magnetic bubble memory devices, which have been put into practical use in recent years, consist of rectangular solenoid coils with an asymmetrical structure mounted on an E-shaped ceramic or synthetic resin wiring board on which a magnetic bubble memory chip is mounted. It has a structure in which an X coil and a Y coil are inserted and arranged orthogonally. The X coil and Y coil have a structure in which they wrap not only the magnetic bubble memory chip but also a wiring board that is much larger than the chip, so the length from one end of each coil to the other becomes long, resulting in increased drive voltage and power consumption. ° In addition, the X coil and Y coil require a uniform inductor balance in order to provide a uniform and stable in-plane rotating magnetic field to the magnetic bubble memory element, so the coil shapes are different from each other and have an asymmetric structure, resulting in a larger structure. I had no choice but to do so. Furthermore, a pair of permanent magnet plates that apply a perpendicular bias magnetic field to the magnetic bubble memory element and a magnetic shunt plate are arranged on the outer surfaces of these X coils and Y coils, and their peripheral parts are covered with a resin mold. Because of this structure, the stacking thickness in the vertical direction increases, which is an obstacle to the demand for thinner and smaller magnetic bubble memory devices.

The closest prior art to the present invention known to the applicant is Patent Application Publication No. 55129 of 1974. This publication describes the structure of a frame-shaped core that surrounds a chip and a conductive magnetic field reflection box that completely surrounds them. However, no further specific structure is shown, and it is theoretically impossible to make an electrical connection to a chip completely surrounded by a conductor case from outside the conductor case without shorting it. Although it is possible, the description is clearly insufficient for people to think of putting it into practical use, including the fact that the method of attaching permanent magnets, magnetic shunt plates, bias coils, etc. is unknown. In other words, the embodiment of the present invention merely coincidentally coincides with the description in the above-mentioned publication in that a frame-shaped core is used as a result.

[Purpose of the invention]

An object of the present invention is to provide a magnetic bubble memory that can be made thinner.

Another object of the present invention is to provide a magnetic bubble memory that can be miniaturized by reducing the overall volume.

Another object of the present invention is to provide a magnetic bubble memory with reduced power consumption.

Another object of the present invention is to provide a magnetic bubble memory in which the VI product is reduced by reducing the inductance of the rotating magnetic field generating coil.

Another object of the present invention is to provide a magnetic bubble memory that allows or facilitates automation of assembly of component parts.

Another object of the present invention is to provide a magnetic bubble memory capable of increasing the number of connection terminals for input/output, etc., such as increasing capacity.

Another object of the present invention is to provide a magnetic bubble memory in which the inclination angle of the magnetic bubble memory element with respect to the direction of the bias magnetic field can be set easily and with high precision.

Another object of the present invention is to provide a magnetic bubble memory whose cassette can be made smaller.

Another object of the present invention is to provide a magnetic bubble memory whose peripheral circuitry can be manufactured at low cost.

Still another object of the present invention is to provide a magnetic bubble memory in which bias magnetic field adjustment or generation coils can be mounted at low cost or easily.

[Summary of the invention]

According to one embodiment of the present invention, a drive magnetic circuit using a frame-shaped core COR is provided (FIG. 8).

Magnetic bubble memory chip CI (I is picture frame-shaped core c.

It is placed on the flexible wiring board FPC so as to be surrounded by R and to be substantially flush with it (FIG. 13). The drive magnetic circuit COR and the magnetic bubble memory chip CHI are housed in a rotating magnetic field confinement case RFS made of a non-magnetic and highly conductive material (FIG. 13).

The flexible wiring board FPC is provided with a conductive pattern 9f so as to surround the magnetic bubble memory chip CHI when viewed in a planar arrangement (FIG. 32). This conductor pattern 9f is used for magnetizing the bias magnet MAG, adjusting the magnetic field strength,
It is used for bias magnetic field margin measurement and bubble elimination operations during testing and use.

According to such a configuration, it is possible to reduce the cost, size, and thickness of the bias coil, and reduce the assembly cost.

[Embodiments of the invention]

Next, the present invention will be explained in detail using the drawings.

(Overview of overall structure Figures 1 and 2) Figures 1 and 2 (a) and (b) are diagrams for explaining an embodiment of the magnetic bubble memory device according to the present invention. FIG. 2(a) is a partially broken perspective view, FIG. 2(a) is a bottom view thereof, and FIG. 2(b) is a sectional view taken along line 2B-2B of FIG. 2(a). In these figures, CHI is a magnetic bubble memory chip (hereinafter referred to as a chip). In these figures, the chip CHI is omitted and only one chip is shown, but in this example, two chips are arranged side by side. shall be.

(The chip yield is better with a multi-divided chip configuration that matches the total storage capacity than with one large-capacity chip.) F
The PC is equipped with two chips CHI and a chip C in the four corners.
This is a flexible wiring board (hereinafter referred to as a board) having a wire group extension for connecting the HI and external connection terminals. Co1
is a drive coil (2) surrounding two chip CRTs with approximately the same plane (2) and arranged so that opposing sides are parallel to each other.
(hereinafter referred to as coil), COR is a rectangular coil assembly C
A frame-shaped core (hereinafter referred to as the core) made of a fixedly arranged soft magnetic material that is provided so as to penetrate the hollow part of the OI.
, and this core COR and each coil COT make the chip C
Magnetic circuit that applies an in-plane rotating magnetic field to T-T I) F
It constitutes C. R, F S are the central rectangular part of the board FPC, two chips CHI and magnetic circuit PFC.
This is a rotating magnetic field confinement case (hereinafter referred to as the case) that houses the entire .

Case RFS is formed by processing two independent plates,
The two bottom plates on the sides of the case are electrically connected. A converging portion is formed in the peripheral portion so that the gap in the central portion is narrowed in a slightly wider range than the portion where the chip CHI is arranged. This constriction can also be used to position the magnet. Case PFS uses magnetic field confinement and soft substrate F.
It has the effect of killing two birds with one stone by mechanically supporting the PC.

In particular, there is a chip C between the case PFS and the chip CHI.
There is a gap SIR on the side surface of I (I), but this gap SIR, including the flat surface of the chip CHI, is coated or filled with silicone resin to prevent foreign matter from adhering to the main surface of the chip during assembly or after assembly. A passivation effect is intended to reduce moisture intrusion into the main surface or side surfaces of the chip.If a complete hermetic seal can be achieved on the outside of the case RFS, filling of the resin SIR can be omitted. Good. INM is a pair of inclined plates made of magnetic material placed on the outside of the case RFS.
The plate thickness of M becomes thicker toward the right, and both have an inclined surface formed on the case RFS side. Inclined plate INM
As the material, soft ferrite, permalloy, etc., which has a high magnetic permeability μ and a small coercive force HC, may be used.
I chose. MAG is a pair of permanent magnet plates (hereinafter referred to as magnet plates) arranged inside the pair of inclined plates INM and overlapping them. The ROM is a pair of magnetic shunt plates made of a magnetic material such as soft ferrite and arranged inside each magnet plate MAG and overlapping with it. The magnet plate M A G is formed to have a uniform thickness over the entire surface. The INN is a pair of inclined plates made of a non-magnetic material with good thermal conductivity such as copper, which are placed on the inner facing surfaces of the pair of magnetic shunt plates HOM and overlapped therewith. These inclined plates INN are inclined plates I
It is formed with an inclined surface having an inclination angle substantially equal to that of NM and in an opposite direction. The inclined plate INM, magnet plate MAG, magnetic shunt plate HOM, and inclined plate INN are arranged in a stacked manner and integrated to form a bias magnetic field generating magnet body BIM (hereinafter referred to as magnet body), when the entire laminated plate magnet body is formed. The thickness is uniform over almost the entire surface.

A pair of magnet bodies BIM are adhered to a central flat part surrounded by the constriction part of the case RFS.

BIC is a bias magnetic field generating coil (
(hereinafter referred to as bias coil). The bias coil BIC adjusts the magnetic force of the magnet plate MAG to match the characteristics of the chip CHI, and when testing for the presence or absence of unnecessary bubble generation, it clears all bubbles on the chip CHI.
It is driven when SHI includes a case RFS that houses the board FPC on which the chip CHI is mounted and the magnetic circuit PFC, and a pair of magnet bodies BIMa and BI on the outside.
This is an external magnetic shield case (hereinafter referred to as shield case) made of a magnetic material that houses Mb and bias coil BIC. As the material for the shield case S HI, a magnetic material with high magnetic permeability μ, large saturation magnetic flux density Bs, and small Hc is preferable, and permalloy and ferrite have such characteristics, but in this example, bending Permalloy iron, which is suitable for
A nickel alloy was chosen. PKG is a packaging case made of a material such as Afl, which has high thermal conductivity and is easy to process, and is attached to the outer peripheral surface of the shield case SHI by adhesion or fitting. GNP are contact pads extending from the four corners of the board FPC and arranged to contact external connection terminals folded back on the back surface of the shield case SHI. TEF
is a terminal fixing plate made of an insulating material that supports and fixes each contact pad GNP at the stepped portion of the opening. REG is sealed in the four inner corners of packaging case PKG, and the shield case RFS assembly is sealed in packaging case P.
This is a resin molding agent that is fixed inside the KG.

(Features of the overall structure, FIGS. 1 and 2) The features of the overall structure of the magnetic bubble memory device shown in FIGS. 1 and 2 are enumerated as follows. However, the features of this embodiment are not limited to these, and other features will become clear from the explanations that follow from Figure 3, but here we will focus on the relationships between each component. The features are described below.

(1) Since the rotating magnetic field generating coil PFC is shaped like a picture frame and the bubble memory chip CHI is arranged on the same plane within the frame, the thickness of the entire bubble device can be reduced. This is because in the current mainstream technology, the lower surface of the chip is wrapped round and round with X and X coils, so the overall thickness of the device is a function of the sum of the chip thickness, the X coil thickness, and the Y coil thickness.

(2) Since the X coil and the X coil are arranged on almost the same plane, there are the following effects compared to the conventional structure in which the X coil is wound on top of the X coil.

■The total winding length of the coil does not become long. Therefore, the inductance L can be reduced, making it possible to drive at low voltage and reduce power consumption.

(2) The distance between the X coil and the X coil and the chip CHI can be made equal, and the magnetic field distribution can be made balanced.

(3) Since the rotating magnetic field generating coil PFC is surrounded by the conductor case RFS, leakage of magnetic flux is reduced and drive efficiency for the chip CHI can be increased.

(4) The conductor case PFS is a rotating magnetic field Hr generating coil P
It prevents the alternating current magnetic field generated from the FC from leaking to the magnet body BIM with a large magnetic permeability μ, and on the other hand, substantially blocks the passage of the direct current magnetic field of the bias magnetic field Hb that should be applied from the magnet body BIM to the chip CHI. There is an option not to.

(5) Since the conductor case PFS is made of a material such as copper, which is harder than epoxy glass or the like conventionally used for wiring boards, it can mechanically support the chip CHI firmly.

Therefore, when a multiple-chip mounting configuration is used to increase manufacturing yields, variations in the inclination angle between chips have a large effect on magnetic properties, but according to this embodiment, variations in the inclination angle between chips can be reduced. It can be held small.

(6) Flexible film board FPC as a wiring board
By using , the following effects can be obtained.

■The board thickness can be reduced.

■Since the lead bonding method can be used, the thickness occupied by the bonding part can be reduced compared to the conventional wire bonding method.

■The effect of ■ above is due to the magnetic circuit gap (magnetic permeability μ
A bias magnet MAG having a small thickness or a small planar area can be used, which leads to a thinner overall device or a smaller planar area.

■Wiring from the chip CHI can be bent freely. Therefore, the terminal portion can be turned over by 180°, and the planar area of the entire device can be limited.

■The width of the opening for wiring out of the rotating magnetic field confinement case RFS can be made smaller. Therefore, leakage of the rotating magnetic field can be kept to a minimum.

(7) Since the external wiring of the wiring board FPC is concentrated at the corners of the rectangle, the opening of the rotating magnetic field confinement case RFS can be provided at the corner where the influence is least.

(8) Since the function of the inclined plate INN is not combined with the magnet or magnetization function, the following effects are obtained.

■Materials with good workability, such as copper, can be used to form the slope.

■Materials with good thermal conductivity such as copper can be used, and the heat generated by the rotating magnetic field generating coil COI can be efficiently dissipated.

■By using non-magnetic material, magnetic shunt plate HO
It is possible to avoid disturbing the magnetic field passing through M.

(9) It is preferable that the inclined plate INN be as thin as possible in order to reduce the magnetic gap.
Compared to G and magnetic shunt plate HOM, by restricting the angle of inclination to the area necessary and sufficient for forming the inclination angle, it is easier to form the inclination angle with a thinner thickness.

(■0) Between magnet M A G and shield case S HI, a plate TN such as soft ferrite with high magnetic permeability μ
Since M is inserted, the magnetic gap between them can be filled. The plate INM also contributes to heat radiation. Since a material having a smaller coercive force He than that of the magnet MAG is selected for the plate INM, the effective thickness of the permanent magnet can be kept uniform.

(11) Since the shield case S HI is made of a magnetic material such as permalloy with a large magnetic permeability μ, the magnet MAG
Since the magnetic resistance of the magnetic circuit using the magnetic field source as the magnetic field source can be reduced, the thickness and planar area of the magnet MAG can be reduced.

(12) Since the shield case SHI is made of a magnetic material such as permalloy with a high saturation magnetic flux density Bs, it has the function of bypassing external magnetic field noise and preventing it from being transmitted to the chip CHI.

(13) The above (11) and (12) each lead to reducing the thickness of the shield case SHH.

(14) Since the shield case SHI uses an iron-nickel alloy such as permalloy, it is suitable for bending and protects the parts incorporated therein against external mechanical forces.

(15) Rotating magnetic field generating coil PFC and bias coil B
Since both ICs are core-type, the storage efficiency or packaging density within the packaging case SHI or PKG can be increased.

(16) Since the case RFS is inserted between the core COR and the magnetic shunt plate HOM, the interval can be finely adjusted by adjusting the thickness of the rotating magnetic field confinement case RFS and the bending angle in addition to the thickness of the coil COI. . The shorter this distance is, the smaller the overall planar size can be, leading to lower power consumption by reducing the coil length.

However, if the distance is too short, the DC bias magnetic field Hb from the magnet MAG will leak to the core COR having high magnetic permeability, and the uniformity of the bias magnetic field in the chip peripheral portion will deteriorate. Therefore, this distance is very critical due to the above-mentioned characteristics, and according to the present structure, it can be precisely adjusted.

(17) Since the constriction portion is provided around the rotating magnetic field confinement case RFS, alignment of the magnet body BIM is easy.

(18) The inclined plate INN is made by arranging two plates made under the same manufacturing conditions so that there is a rotation angle difference of 180° between the top and bottom surfaces of the chip, so that the two plates are made under the same manufacturing conditions. A pair of magnetic shunt plates HOM and a pair of magnets M are arranged.
AG can be aligned almost parallel.

(Overview of assembly Fig. 3) Fig. 3 is an assembly perspective view for explaining the procedure for stacking and assembling each component constituting the above-mentioned magnetic/magnetic bubble memory device, and the same reference numerals as above indicate the same members. ing. In the figure, first, a board assembly BND is mounted on a board FPC, which has connection parts for input/output wiring protruding from the four corners and an element mounting part in the center, and two chips CHI'tr mounted on the bottom surface. After placing an insulating sheet in the outer case RFSa with adhesively arranged at the position indicated by the dotted line, and further incorporating a magnetic circuit PFC on this board FPC, silicone resin 5IR (not shown) is filled and the upper part is filled with silicone resin 5IR (not shown). The inner case RFSb is assembled into the outer case RFSa, and the side contact portions of the outer case RFSa and the inner case RFSb are electrically connected by soldering or the like. Next, the upper magnet body B I
After arranging M a and the lower magnet BIMb, the outer edge of the upper magnet B I M a and the inner case RF
A bias coil BIC wound in alignment is arranged in a gap (not shown) formed between the inside of the Sb, and these are housed in the outer case S HI a.The inner case 5 HIb is further incorporated, and the outer case S HI a and the inner case are assembled. 5HI
Magnetically connect the side contact portion with b by welding or the like.

Next, connect the external connection terminal connection portions of the board FPC protruding from the four corners of the inner case 5HIb to the inner case 5HIb.
As shown in FIG. 4B, the connectors are folded back on the back side of B and arranged in combination to have a certain shape, and contacts (not shown) are attached to each external connection terminal covered with solder or the like provided at each of these connection parts. A terminal fixing plate TEF with a pad COP mounted in each opening is placed in contact with the terminal fixing plate TEF, and each external connection terminal and contact pad COP are electrically connected by soldering or the like by thermocompression bonding or the like. Next, these assembled bodies are stored in the packaging case PKG, and the terminal fixing plate T is attached.
The EF and the packaging case PKG are assembled by sealing with a hermetic seal or the like at the contact area.

Next, the structure of each component mentioned above will be explained.

(Flexible wiring board Fig. 4) Fig. 4 is a diagram showing a board FPC, where A is a plan view thereof and B is a layout in which the connection parts of external connection terminals protruding from the four corners are folded back and combined. Plan view C is an enlarged cross-sectional view of 4C-4G of figure A, and the same figure is 4D- of figure A.
It is a 4D enlarged sectional view. In the same figure, the board FPC is
There is a square element protection part 1 in the center, small bent parts 2 (2a, 2b, 2c, 2d) at the four corners, and a square external connection terminal connection part (hereinafter referred to as connection part) at the tip. ) 3 (3a, 3b, 3c, 3d), and the overall shape is approximately windmill-shaped and is integrally formed. rectangular openings 4 (4a, 4b) with double frame structure to which chips CHI are mounted and their terminals connected, and 3 for positioning.
perforations 5 (5a, 5b, 5c) are provided, and one
A board protrusion 6 for positioning is provided at the tip of each connecting portion 3C.

In addition, as shown in FIG. C, this FPC board is made by forming a copper thin film on a base film 7 made of a polyimide resin film with a thickness of about 50 μm, for example, via an epoxy adhesive 8, and then applying the copper thin film to the desired shape. By etching into a pattern shape, wiring leads 9a as shown in FIG.
A circular external terminal 9b and an oval coil lead connection terminal 9c.

Patterns such as symbols 9d and index marks 9e are formed, and a transparent or semi-transparent cover film 10 is adhered to the upper surface of these through an adhesive 8 made of the same material as described above. And this board FP
In the opening 4 of C, an opening with highly accurate dimensions is formed in the base film 7 on which the chip CHI (not shown) is mounted, and an opening with relatively large dimensions is formed in the cover film 10 on the upper surface side. Further, a wiring lead 9a is exposed between the base film 7 and the cover film 10, and a tin plating layer 1 is formed on the surface of the wiring lead 9a.
1 is formed, and the opening shape is formed to have a two-layer structure and a double frame structure.

On the other hand, in the connecting portion 3, a cover film 10. A circular opening 12 is formed in a portion corresponding to the circular external terminal 9b and the oval external terminal 9c (not shown), and the copper thin film pattern of the external terminals 9b and 9c exposed from the opening 12 is plated or dipped. A solder layer 13 is formed by, for example. The external terminals 9b, 9c provided on these connecting portions 3 are connected to the connecting portions 3a, 3b, 3c, 3d and the bent portions 2a, 2b.
, 2c, 2d and each wiring lead 9a formed continuously on the element protection part 1, and these wiring leads 9a are connected to each opening 4a, 4b provided in the element mounting part 1.
The connection parts 3a, 3b, 3c, 3d are gathered in blocks at a part of the opening ends of the openings 4a, 4. b
exposed inside. That is, as shown in FIG.
The wiring lead 9a of the connecting portion 3b is located at the lower left of the opening 4b, the wiring lead 9a of the connecting portion 3c is located at the upper right of the opening 4a, and the wiring lead 9a of the connecting portion 3d is located at the lower right of the opening 4b. are wired to each.

Then, this board FPC is connected to each connection part 3a, 3 in a later process.
b, 3c, and 3d are the respective bent portions 2a, 2b.

2c and 2d are bent and assembled as shown in FIG. is cover film 1-
0, these patterns are configured so that they can be easily read through the cover film 1o.

In such a configuration, the substrate FPC uses a polyimide resin film, and each bent portion 2 is provided at the four corners of the element protection portion 1.
Each connection 3a, 3b, 3 via a, 2b, 2c, 2d
c, 3d, and each of these connecting parts 3
By folding and combining a, 3b, 3c, and 3d to form the external terminal section, the element protection section 1 and the connection section are separated into two parts.
Since it has a layered wiring structure, the area of the element protection part 1 can be increased without reducing the area of the connection part 3, and at the same time, it is possible to increase the number of external terminals, and the overall shape can be made smaller. .

In addition, in such a configuration, the wiring leads 9a from each external terminal 9b to each opening 4a, 4b of the element protection part 1
Since the time can be significantly shortened, the influence of external noise etc. can be significantly reduced. That is, signals with a high S/N ratio can be input and output. Furthermore, a board protrusion 6 is provided at one end of the connecting part 3c, and an index mark 9e is provided on this protrusion 6, so that it can be used for displaying the central part of the board when folded back and assembled.
I (see Figure 2) for positioning, distinguishing the type of wiring lead 9a, or displaying the product model. Rationalization = 23- can be done. Furthermore, by providing the perforations 5a, 5b, and 5c on both ends of the element protection part 1 of the FPC board, it becomes easy to distinguish between the left and right sides of the FPC board, position the chip CH, etc., and similarly streamline assembly. I can do it.

(Substrate Assembly Figures 5.6.7) Figure 5 shows a plan view of the chip CHI mounted on the FPC substrate described above. In the same figure, the board FPC
Two chips CHI are placed in the element mounting section 1 through the opening 4. a
, 4b are arranged in parallel to form a board assembly BND, and one of the chips CHI is constructed by integrating two blocks of IMb chips, as shown in an enlarged plan view in FIG. , 4 blocks for 2 chips CHI,
4 in total. It constitutes the Mb chip. In addition, the 6th
In one block of the chip CHI shown in the figure, thick lines indicate conductor patterns and thin lines indicate chevron pattern transfer paths, respectively. The chip CHI shown in FIG. 5 also has bonding pads 14 provided at the ends of the chip CHI by gold plating, as shown in enlarged cross-sectional views in FIGS. 7A and 7B, respectively. and,
A gold bump 15 is interposed between the tin plated layer 11 of the substrate FPC opening 4 and the wiring lead 9a formed thereon, and lead bonding is carried out using Au-Sn eutectic using a thermocompression bonding method. .

According to such a configuration, the openings 4, a,
The wiring lead 9a of 4b and the bonding pad 1.4 of the chip CHI are connected by lead bonding using Au-Sn eutectic, and the chip CHI can be supported and fixed. It becomes possible to take shape. Also, the surface of the chip CHI is connected to the substrate FP.
Since it is covered by the element mounting part 1 of C, the chip CHI
The surface of the FPC can be protected, handling properties can be improved, and the mechanical strength of the FPC board can be maintained. Furthermore, according to such a configuration, each chip CHI consists of two blocks, and two chips CHI consist of four blocks.
Since it is composed of blocks, each block can be distributed and wired to the nearest connection parts 3a + 3b, 3c, and 3d, and symmetry in the chip CHI arrangement can be obtained.
Tests, inspections, etc. become extremely easy. Furthermore, since four connection parts 3a, 3b, 3c, and 3d are provided on the FPC board, the wiring for the magnetic bubble detector DET and maple loop of each chip CHH can be separated from other functional wiring and connected to one connection part. By selecting and arranging this connecting portion at a location away from the noise generation source, input/output signals with extremely low noise can be exchanged.

(Drive Magnetic Circuit FIGS. 8 and 9) FIG. 8 is a diagram showing the magnetic circuit PFC, in which figure A is a perspective view and figure B is a plan view showing the drive magnetic circuit.

In the figure, the magnetic circuit PFC has a frame-shaped core COI made of soft magnetic material. , windings are made in the direction of the arrows on opposite sides parallel to each other to form four sets of coils 20a and 20b.
, 20c, and 20d are wound, and the coils 20a and 20b on opposite sides are connected to the connection point 2.
The X coil 22a is formed by winding the coils 20c and 20d in series through the connecting point 21a, and the Y coil 22b is formed by winding the coils 20c and 20d in series through the connection point 21a.

Then, the currents Ix and Iy (for example, triangular non-current) whose phase is accumulated by 90 degrees in the X coil 22a and the Y coil 22b
As shown in Figure B, a leakage magnetic field Hz is generated in the X-axis direction and a leakage magnetic field Hy is generated in the y-axis direction.
It is supplied as a rotating magnetic field to the two chips CHI mentioned above.

In addition, the magnetic circuit PFC configured in this manner has windings arranged around a rectangular parallelepiped magnetic core 23 made of one soft magnetic material with taps 24 for each block, as shown in a perspective view in FIG.
are provided and wound in series to form a pair of coils, for example coil 20.
After forming a pair of X coils 22a consisting of coils 20a and 20b, a wide groove 25 having a constant l] and a narrower groove 26 are cut and provided between each coil 20a and 20b, Thereafter, the wide grooves 25 that are cut from the narrow groove 26 are assembled and glued together in directions orthogonal to each other to form a picture frame shape as shown in FIG. Alternatively, the pair of X coils 22a may be formed by winding the coils 20a and 20b through the taps 24 around the rectangular parallelepiped core 23 in which the wide groove 25 and the narrow groove 26 described above are formed in advance. . Furthermore, the pair of Y coils 22b described above are formed in exactly the same manner.

In such a configuration, the coils 20a and 20b are wound in series around the rectangular parallelepiped magnetic core 23 with taps 24 provided, so when assembled as shown in FIG. 8, the wires are connected by crossing each other ( connection points), and the winding routing can be simplified.

According to such a configuration, the X coil 22a and the Y coil 2
2b has a symmetrical structure, resulting in a rough coupling,
The inductance balance is improved, and magnetic interference between magnetic bodies due to leakage magnetic fields can be prevented. Further, since the magnetic circuit PFC has a frame-shaped structure that is not placed on the upper or lower surface of the chip CHI, the thickness in the stacking direction is reduced, making it possible to reduce the thickness.

(Rotating magnetic field confinement case Fig. 10.11.12) 1st
Figure 0 is a diagram showing the case RFS, and Figure A is a plan view.
Figure B is a sectional view taken along the line 10B-10B. In the figure, the inner case RFSb has a frame-shaped constriction part 30 whose central part is concave, and whose opposing end sides extend upward by approximately 90 degrees.
The case RFSb has a bent portion 31 bent at 0 degrees and cutout portions 32 cut diagonally at each of its four corners, and the case RFSb is made of a highly conductive material,
For example, it is formed by pressing an oxygen-free copper plate. In this case, the constricted portion 30 and the bent portion 31 can improve the mechanical strength of the inner case RFSb in the torsion direction, and can appropriately limit the outer diameter dimensions in the longitudinal and lateral directions between the bent portions 31 facing each other. . Further, the aperture section 30 can appropriately adjust the distance between the magnet body BIMb arranged on the outer surface side of the case RFSb and the chip CHI arranged on the inner surface side. Note that the cutout portions 32 provided at the four corners are each bent portion 2a of the board FPC disposed within this case RFSb.

It forms the drawer parts 2b, 2c, and 2d.

According to such a configuration, the inner case RFSb can be formed by a press working method, and therefore can be manufactured with high precision dimensions and at low cost.

Note that, although oxygen-free copper is used for the inner case RFSb, a plate material made of copper, silver, gold plate, or an alloy plate thereof may be used.

FIG. 11 is a diagram showing an outer case RFSa corresponding to the inner case RFSb described above, in which FIG. 11A is a top view and FIG. 11B is a 11.8-1. iB sectional view. In the same figure, this outer case RF S a is formed using the same materials and manufacturing method as the above-mentioned inner case RF S b, and its structure is almost the same as above, with a frame-shaped constriction part with a concave center. 33, a bent portion 34 whose opposing end sides are bent at approximately 90 degrees in two directions, and a notch portion 35 cut diagonally at each of its four corners. In this case, the mutually opposing bent portions 34 are formed so that the inner dimensions thereof are approximately the same as the outer dimensions between the bent portions 31 of the inner case RFSb described above, and the height H is increased. has been done.

Note that the constricted portion 33 and the notch portion 35 are formed to have substantially the same dimensions as the aforementioned inner case RFSb.

The outer case RFSa and the inner case RFSb configured in this way are shown in a plan view in FIG. 12A and in FIG. 12B.
As shown in the 1-2 B-12B cross-sectional view, the inner case RFSb is inserted into the outer case RFSa, and the outer surfaces of the bent portions 31 of the outer case RFSa are brought into contact with each other and connected. case RF
S is assembled.

(Case assembly Figure 13) Figure 13 shows the board assembly BNI in the case RFS mentioned above.
In this figure, a polyimide film 36 with a thickness of about 0.1 m, for example, is adhesively arranged on the bottom surface of the outer case RFSa as an electrically insulating sheet. , on this film 36 is a substrate assembly BND, and on its periphery is a magnetic circuit @F.
After the PCs are respectively arranged and an epoxy adhesive 37 is applied to the upper surface of the board assembly BND, an inner case RFSb is inserted into a part of the upper part 31 of these and is arranged to be bonded. In this case, the inner surface of the bent portion 34 of the outer case RFSa and the outer surface of the bent portion 31 of the inner case RFSb are electrically and mechanically joined by metal flow, soldering, etc. at the portion indicated by the X mark. Furthermore, the gap between the outer case RFSa and the inner case RFSb is filled with silicone resin SIR to form the board assembly BN.
D and magnetic circuit PFC are fixedly arranged. In addition,
In this case, the notches 32 and 35 (not shown) provided at the four corners of the outer case RFSa and the inner case RFSb have the folded Il1 opening f part 2 (
2a, 2b, 2a, 2d) are drawn out. 3
8 is a lead wire for connecting the coil COIs or connecting the coil COI to an external terminal 9c provided on the FPC board.

In such a configuration, when a leakage magnetic field is generated by driving the magnetic circuit FPC, an induced current flows through the case RFS to form a closed loop, and this induced current confines the rotating magnetic field within the case RFS. Therefore, a uniform rotating magnetic field is applied to the chip CHI.

According to such a configuration, the chip CHI mounted on the board FPC is held in the concave part of the central part between the outer case RF Sa and the inner case RFSb, and the magnetic circuit PFC is held in the convex part of the peripheral part. Since they are arranged in parallel, the packaging effect can be improved and the ease of assembly can be greatly improved.

In addition, outer case RF S a and inner case RFs
By reducing the volume covered by b, the VI product (volume) can be reduced, and the magnetic circuit PFC that generates the rotating magnetic field can be downsized. Furthermore, by providing concave portions formed by constricted portions 30 and 33 in the outer case RF S a and the inner case RFS b, the gap between the opposing concave portions is reduced, so that the rotating magnetic field has a component perpendicular to the plane of the chip CHI. (Z component) is close to zero and there is only a horizontal component, and uniformity can be improved.

(Magnet Figure 14) Figure 14 is a diagram showing the magnet body BIM, in which Figure A is a plan view, Figure B is a side view, and Figure C is a front view.

In the figure, the magnetic body BIM includes an inclined plate IN made of a non-magnetic material, such as copper, and one of the opposing surfaces has a predetermined inclined surface.
N, this inclined plate ■ A first magnetic shunt plate HOM 1 of uniform plate thickness arranged on the slope side of NN, and this first magnetic shunt plate HO
A magnet plate MAG with uniform plate thickness placed on the upper surface side of M□,
A second magnetic shunt plate HOM2 having an inclined surface is sequentially laminated on the upper surface side of this magnet plate MAG, and is integrated with an epoxy adhesive, so that the entire laminated plate thickness is uniform over almost the entire surface. It is configured as follows. A uniform magnetic field for generating a bias magnetic field is emitted from the upper and lower surfaces of this magnet body BIM over almost the entire surface.

(Bias Coil FIG. 15) FIG. 15 is a diagram showing the bias coil BIC, where A is a perspective view and FIG. B is a cross-sectional view taken along line 15B-15B. In the same figure, the bias coil BIC has a winding 40 whose outer surface is coated with an insulating member such as a thermosetting resin, and is wound in an array with a cross section of 5 x 4 wires so that the overall shape has a picture frame shape. After that, it is crimped by heat welding, cooled, and formed into a frame shape of a predetermined value. In this case, the thermosetting resin coated on the outer surface of each winding 40 is thermally welded to each other, and each winding 40 is clogged and formed by pressure bonding, and by cooling, each winding 40 is hardened in a bundled state. Therefore, it is formed into a predetermined picture frame shape.

(Mounting the magnet and bias coil on the case assembly
(FIG. 16) FIG. 16 is a sectional view of the case RFS assembly described in FIG. 13 incorporating the magnet body BIM and bias coil BIC. In the same figure,
An upper magnet body BI Ma and a lower magnet body B IMb are adhesively arranged on the upper and lower surfaces of the case RFS assembly that houses the board assembly BND and the magnetic circuit PFC inside, respectively. A bias coil BIC is housed in a frame-shaped groove formed by being surrounded by the peripheral edge of the inner case RFSb and the bent portion 31 of the inner case RFSb. In this case, the upper magnet body BIMa and the lower magnet body BIMb are made of the same material and 9 dimensions, and the inclined plate INN side of these magnet bodies BIMa and BIMb is connected to the constriction part of the inner case RFSb. 30 and the concave portion surrounded by the constriction portion 33 of the outer case RFSa in close contact with each other.

In such a configuration, a pair of magnet bodies BIMa,
Since the BIMb is placed and the bias coil BIC can be placed in the frame-shaped groove formed on the periphery of the BIMb,
The overall thickness of each component in the stacking direction is reduced, making it possible to make it smaller and thinner. In addition, the outer case RF Sa
A frame-shaped space groove is formed between the outer edge portion of the lower magnet body BIMb, and the bias coil BI is inserted into this portion.
C may be arranged, a bias coil may be newly provided, and furthermore, a bias coil may be formed by winding a wire as a coil bobbin.

(Magnetic shield case Fig. 17, 18, 19) Fig. 17
The figures show the shield case SHI, with figure A being a plan view and figure B being a 17B-17B cross-sectional view thereof. In the same figure, the outer shield case S HI a has a flat portion 51 and an end side opposite to the flat portion 51 that extends upward by approximately 90 mm.
The folded part 52 that is folded back at the same time, and the folded part 52
The shield case S HI a has a recess 53 partially cut out in the center thereof, and a notch 54 cut diagonally at each of its four corners.This shield case S HI a has a high magnetic permeability. It is formed by pressing a material having a high saturation magnetic flux density and preferably a high thermal conductivity, such as a permalloy plate.

FIG. 18 is a diagram showing an inner shield case 5HIb corresponding to the above-mentioned outer shield case 5HIa, with FIG. 18A being a plan view and FIG. 18B being a 18B-18B sectional view thereof. In the figure, this inner shield case 5HIb is
It is formed using the same material and manufacturing method as the outer shield case SHI a described above, and its structure is almost the same as described above, with a flat part 55 and an opposite edge of the flat part 55 folded at approximately 90 degrees in two directions. It has a bent portion 56, a recessed portion 57 partially cut out in the center of the bent portion 56, and notched portions 58 cut diagonally at each of its four corners. In this case, the mutually opposing bent portions 56 have an outer dimension approximately equal to the inner dimension between the bent portions 52 of the outer shield case SHIa, and have a height I-■. It is made smaller.

The outer shield case SHTa and the inner shield case 5HIb configured in this way are shown in FIG. 19A as a plan view and as shown in FIGS. Insert the inner shield case S HI b into the inner shield case S HI b, and remove the four parts 5 formed by the recess 53 of the outer shield case S HI b and the recess 57 of the inner shield case S HI b.
9 is subjected to spot welding or solder welding, and is magnetically and mechanically fixed to be integrated, thereby assembling the outer shield case S HI a.

In such a configuration, the outer shield case S HI
The bent part 52 of a and the inner shield case S H
By setting the bent portion 56 of Ib in the lateral direction, that is, in the direction that intersects with the stacking direction, by aligning it with the stacking direction, the lateral dimension can be reduced, resulting in a small size and high integration of component parts. becomes possible.

(Magnetic shield case assembly Fig. 20) Fig. 20 shows the above-mentioned shield case SHI assembly.
The board assembly END and magnetic circuit FPC are inside as explained in the figure.
A case RFS assembly incorporating the BI
A cross-sectional view incorporating an assembly consisting of Ma, BIMb, and bias coil BIC is shown. In the figure, inside the outer shield case S HI a, there is an upper magnet body B I M a from the bottom side to the center, a bias coil BIC at the periphery, and a case RFS assembly (board assembly END and magnetic After sequentially stacking the lower magnet body BIMb (in which the circuit PFC etc. is incorporated),
Insert the inner shield case S HI b and insert the recess 59 (
(see Fig. 19) and is fixed and sealed by welding. in this case,
By filling this shield case SHI with grease, etc., the internal components will come into close contact with each other, and the heat generated from the case RFS will be released to the outside through this shield case SHI. can do. In addition, case RFS and shield case ST (I
The heat dissipation effect can be improved by using a structure in which the parts are brought into contact with each other on the sides using a press-fitting method.

In such a configuration, the outer shield case ST (
By stacking the case RFS assembly on the bottom side of Ia so that the bent parts 31 and 34 thereof face each other, each component stacked between the outer shield case SHIa and the inner shield case 5HIb can be stacked. Since they can be placed in close contact with each other, they can be made smaller and thinner, and a heat dissipation effect can be obtained at the same time.

(Packaging case FIG. 21) FIG. 21 is a diagram showing a packaging case PKG, in which FIG. 21A is a plan view and FIG. 21B is a 21B-21B sectional view thereof. In the figure, the packaging case PKG is formed by drawing a material with good thermal conductivity, for example, an aluminum plate with a thickness of about 0.5 mm, and has a black coating on its outer surface (not shown). There is. This packaging case PKG includes the outer shield case 5.
The shape of HIa can be improved and used for both purposes.

In such a configuration, this packaging case P
The KG serves as an outer case after the magnetic bubble memory device is completed and also functions as a heat sink, and its inner corner also functions as a mold during resin molding by the potting method described later.

(Terminal fixing plate and contact pad Fig. 22.23)
FIG. 22 is a diagram showing the terminal fixing plate TEF, in which FIG. 22A is a plan view, FIG. 22B is a sectional view taken along line 22B-22B, and FIG. 22C is a rear view thereof. In the figure, the terminal fixing plate TEF is made of an electrically insulating material.

For example, it is made of a glass epoxy resin plate 60, and its outer shape is formed to have vertical and horizontal dimensions that allow it to be inserted into and removed from the opening of the packaging case PKG. A large number of through holes 61 are formed in a matrix arrangement at predetermined intervals in the vertical and horizontal directions in areas other than the peripheral area, and furthermore, the corners of these through holes have concave cross sections that are not rotationally symmetrical. A non-through hole 62 is provided, and a mark 63 made of, for example, a white coating film for locating directionality or features is attached inside this non-through hole 62. In addition, as shown in FIG. B, a large number of through holes 61 formed in the resin plate 60 are provided with large diameter openings 64 coaxially communicating with each other on the back side thereof, as shown in FIG. All of the openings 64 are approximately 60 mm thick of the plate.
%, and communicates with the through hole 61 with a step in the middle. Further, as shown in FIG. C, the back side of the resin plate 60 has a depth approximately equal to the depth of the opening 64 along its peripheral portion, and has a different width in the plane direction and a concave cross section. A groove 65 is formed, and this groove 65
Inside is the winding of the coil COI mentioned above, and the bias coil BI.
It constitutes the passage section and connection section of the winding C. Also,
The corner portion 66 of this resin plate 6° does not have a concave shape, but has a predetermined thickness dimension, and is used in the packaging case PKG described above.
The contact surface is obtained by touching the inner surface of the In this way, the back side of the resin plate 60 is formed to have a two-tiered structure with different plate thicknesses.

FIG. 23 is a diagram showing the contact pad GNP, with FIG. 23A being a plan view and FIG. 23B being a sectional view taken along line 23B-23B. In the figure, contact pads (NP, NP) are formed by forming a nickel plating layer 71 and a gold plating layer 72 on the surface of a piece 70 punched out of a highly conductive material, for example, a copper plate with a thickness of approximately 0.5 mm. It consists of

(Final assembly Figure 20.4.2) Each component configured in this way is first assembled by inserting the shield case assembly described in Figure 20 into the packaging case F'KG described above. Connecting portions 3a, 3b, 3c, 3d (
(see Fig. 4A) are each bent portion 2a, 2b, 2c, 2d.
It bends at about 90 degrees and protrudes. Next, resin molding is performed on the four corners of this packaging case PKG by the botting method to make this packaging case PKG.
Each unique part is fixedly arranged in G. Subsequently, these connecting portions 3a, 3b, 3c, and 3d are further bent at approximately 90 degrees at the corresponding bending portions 2a, 2b, 2c, and 2d, and attached to the outer surface of the inner shield case 5HIb with adhesive as shown in FIG. After assembling as shown in B, contact pads G are inserted into each opening 64 on the back side of the terminal fixing plate TEF.
A packaging case PK is created by mounting the NP or by fixing the side surface of the contact pad GNP with adhesive.
G, and each connection part 3a, 3b, 3c.

Place it in contact with 3d. In this case, each connection part 3a.

Since the arrangement pitch of each external terminal 9b provided in 3b, 3c, and 3d matches the arrangement pitch of each contact pad GNP, each external terminal 9b and contact pad GNP are in electrical contact. .

Next, from the back side of the terminal fixing plate TEF placed, each through hole 61
For example, by inserting a heating element with a thin tip into the contact pad CNP and thermocompressing the contact pad CNP, each external terminal 9b and the corresponding contact pad GNP are electrically connected, and the terminal fixing plate TEF is also mechanically connected at the same time. Once fixed, the magnetic bubble memory device and chair shown in FIG. 2 are completed.

(Magnetic bubble memory element No. 24.25, 26.27.
Figure 28) Figure 24 shows the above-mentioned magnetic bubble memory chip C.
It shows a cross-sectional view of the vicinity of the bonding pad PAD of HI. In the same figure, GGG is gadoliniu
m-galium-garnet substrate,
LPE is a bubble magnetic film formed by liquid phase epitaxial growth, and an example of its composition is shown in Table 1 on the next page.

(This page, below in the margins) Table 1 1ON shows an ion implantation layer formed on the surface of the T-PE film to suppress hard bubbles. SPI is the first spacer, for example 3000 thick Sjo, formed by gas phase chemical reaction.

CND] and CND2 indicate two conductor layers, which have the function of controlling bubble generation, copying (splitting) and exchange, which will be described later, and the lower first conductor layer CND1 is M o
, and the upper second conductor layers CND2 are each formed of a material such as AU. SF3 and SF3 are interlayer insulating films (second and third spacers) made of polyimide resin or the like that electrically insulate the conductor layer CND and the transfer pattern layer P of permalloy or the like formed thereon. PAS is a passivation film made of Sin, film, etc. formed by a vapor phase chemical reaction method. PAD indicates a bonding pad of the chip CHI, to which a thin connector wire such as an AQ wire is bonded by thermocompression bonding or ultrasonic bonding. These bonding pads P A and D are the lower first layer P.
The second layer PAD2 in the center is made of Au layer, and the third layer PAD3 on top is made of Au plating layer.The second layer PAD2 and the third layer PA, D, are made of Cr. It may be formed of a material such as Cu. P indicates a layer used for a bubble transfer path, a bubble division 9 generation, exchange and detection section, and a guardrail section, and in the following description, it will be expressed as a transfer pattern layer for convenience.

In the example of FIG. 24, this transfer pattern layer P is attached to the lower layer P, F
e-Ni is used for the upper layer P2, and Fe-Ni is used for the upper layer P2, but as described above, it is also possible to interchange the two materials vertically.

Hereinafter, an example in which the transfer pattern layer consisting of multiple layers described above is applied to each part of the chip CHI will be explained using the plan views from FIG. Note that they are represented by the same contour line because they are the same. Figure 25 shows the bubble detector part, where MEM is the main magnetoresistive element, which uses the change in resistance value when bubbles stretched in a strip shape in the horizontal direction pass through it to detect the presence or absence of bubbles. Detect. MED is a dummy magnetoresistive element having a pattern similar to that of the main magnetoresistive element MEM, and is used to detect noise components due to the influence of a rotating magnetic field. On both sides of the main magnetoresistive element MEM, several ten stages of bubble stretchers ST are formed, although only two stages are shown, which stretch the bubbles laterally and transfer them downward. Note that PR indicates the bubble transfer direction. E
R is a bubble eraser, and when a bubble reaches the conductor layer CHD, it is erased. A guardrail GR consisting of three rows of pattern groups is provided around this detector and between the dummy and main detection. It is designed to prevent unnecessary bubbles generated on the outside from entering the inside. In the plane pattern diagrams shown in FIG. 25 and subsequent figures, patterns other than the conductor layer CND indicate the transfer pattern layer P explained in FIG. 24. In the same figure, by forming the magnetoresistive elements MEM and MED with multilayer magnetic layers, the signal-to-noise ratio (S/N
ratio) improved. For example, when a three-layer permalloy layer with Sj, 02 film interposed between each layer is used as a transfer pattern, the S/N ratio is more than doubled compared to that for a single layer of permalloy, as shown in Table 2 below. can be done.

Table 2 Furthermore, the performance of the guardrail GR is also improved, such as by increasing the removal rate of unnecessary bubbles due to the reduction in the holding force Hc.

FIG. 26 shows a magnetic bubble generator GEN in which the transfer pattern layer P is multilayered.

The current generated by magnetic bubbles can be reduced, and the life of the conductor layer CND of the magnetic bubble generator can be extended. Therefore, a semiconductor element with a small current capacity value can be used for the drive circuit of the conductor layer CND, and the cost can be reduced.

FIG. 27 shows a swap gate section formed of a write major line WML formed of transfer pattern rows such as minor loops m, Pw, to PW3 formed of transfer patterns such as P a "P h, and a hairpin-shaped conductor layer CND. In the same figure, P7 is the same as the transfer pattern P7 in the bubble generator GEN of FIG. 26. In other words, the bubble generated by the bubble generator GEN is P.

~ Write major line WM through the transfer path of P7
Transferred to L. When a current is applied to the swap conductor layer CHD, the magnetic bubbles of the transfer pattern Pd of the minor loop m1 are transferred to the transfer pattern Pw3 of the major line WML through the transfer patterns Pfl and Pm, and the magnetic bubbles from the major line Pw are transferred. Pattern Pk, P
The data is transferred to the minor loop transfer pattern Pe via j and Pi, and the bubbles are exchanged, that is, the information is rewritten. Note that the rightmost minor loop md is not provided with a swap gate, but this is a dummy loop in which no magnetic bubble is injected to reduce the peripheral effect.

In this way, the transfer pattern layer P i − at the exchange position
By forming P m into multiple layers, magnetic bubbles can be exchanged with a small current value.

Further, as shown in FIG. 28, a magnetic bubble copying machine, that is, a divider, can be driven with a small current value as well. In the figure, a magnetic bubble is normally transferred along a path from Pn to Pg, Ps''Px, and when a current is passed through the conductor layer CHD, the bubble is divided at the position of the transfer pattern Pg, and one divided magnetic bubble is transferred. The bubble is P'/t P, ~P,.

and is transferred to the read major line RML.

(Holding magnetic field and rotating magnetic field FIG. 29) Magnet plate MAG is arranged at an angle of about 2 degrees with respect to chip CHI. This is the bias magnetic field Hb for the chip CHI.
The holding magnetic field Hd is applied with a slight deviation from the vertical direction, thereby improving the start and stop margins of bubble transfer by approximately 6 (Oe).
Ctil-generates (Figure 29A).

As shown in Figure 29A, the magnet body BIM and the chip CHI
Due to the zero angle inclination with , the DC magnetic field Hz has a component Hdc in the xy plane.

Then, the size of this in-plane component Hdc is Hdc・5i
Normally HdC-5inθ=5[Oe]~
The inclination angle θ is selected so that the in-plane component Hdc is aligned with the start/stop (St/Sp) direction (+x-axis direction) of the rotating magnetic field Hr. This xy-plane component Hdc is determined by the start/stop (St/
Sp) This is a well-known magnetic field called a holding field that has an effective effect on the operation. Note that the magnitude of the bias magnetic field Hb acting perpendicularly and directly on the chip CHI surface is Hz-CO5θ.

Now, since the above-mentioned holding field HdC always acts on the xy plane of the chip CHI, the 29th
As illustrated in FIG. B, the rotating magnetic field Hr' acting on the chip CHI is eccentric. In the figure, Hr is a rotating magnetic field applied from the outside, and Hr' is a rotating magnetic field acting on the chip CHI. In this case, the rotating magnetic field Hr' acting on the CHH is a combination of the rotating magnetic field Hr applied from the outside and the in-plane component Hdc, and the center 0' of the rotating magnetic field Hr' is in the start/stop (St/Sp) direction. It is translated by an in-plane component Hdc in the +x-axis direction. Therefore, as is clear from the results in the same figure, even if the strength of the externally applied rotating magnetic field Hr is l T-Tr l, the strength of the rotating magnetic field 1r that effectively acts on the chip CHI is
rr'l differs depending on the phase of the rotating magnetic field Hr. That is, 1r-rr'l in the St/Sp direction is IT(rl+
IHd cl, which is stronger than l Hr l by the holding field HdC strength l■Tdcl. On the other hand, IT- in the opposite direction to the St/Sp direction
frl becomes l I-1r l I I-(dcl, and is weakened by 1I(del) compared to l Hr l.

(Peripheral circuit Fig. 30) Finally, the peripheral circuit of chip CHI will be explained with reference to FIG.

RF is a circuit for generating a rotating magnetic field Hr by passing currents with a phase difference of 90° through the X and Y coils of the chip CHI.

SA is a sense amplifier that samples, senses, and amplifies a minute bubble detection signal from the magnetoresistive element of the chip CHI in synchronization with the timing of the rotating magnetic field. DR is MB
This is a drive circuit that causes current to flow at a predetermined timing to each functional conductor of a replicate that is related to bubble generation and swap related to write and read of the M device. The above circuit is synchronized by a timing generation circuit TG so as to operate in synchronization with the cycle and phase angle of the rotating magnetic field Hr.

(Rotating magnetic field distribution characteristics FIG. 31) FIG. 31 shows the rotating magnetic field distribution characteristics of the magnetic circuit PFC described above. That is, in the figure, the horizontal axis represents the length in the X-axis direction with the center of the magnetic circuit PFC shown in FIG. 8B as O, and the vertical axis represents the rotating magnetic field strength Hx in the X-axis direction.
When the rotating magnetic field strength Hx in the X-axis direction is shown when = O, a rotating magnetic field distribution characteristic as shown by curve I was obtained.

As is clear from the figure, a substantially uniform rotating magnetic field strength Hx is obtained within the range of -Xc to +XC between the opposing cores COR of the magnetic circuit PFC, and
Effective area of HI (minimum range to which rotating magnetic field should be applied)
In the range of −X, e to 10Xe, a magnetic field strength uniformity of about 2% was obtained. Note that the curve (2) indicated by a broken line is the rotational magnetic field distribution characteristic of the magnetic circuit of the conventional configuration.

(Modifications) Although the details have been described in connection with the overall structure of the magnetic bubble memory shown in FIGS. 1 and 2, the present invention can be implemented in the following modifications.

FIG. 32 is a diagram showing a modification of the present invention in which a bias coil is provided on a flexible wiring board FPC using printed wiring technology. 32B sectional view is shown, and the same parts as in the previous figure are given the same reference numerals. In the same figure, a bias coil BIC is patterned on the two chips CHI around the periphery of an element protection part 1 on which two chips CHI are mounted on the substrate FPC, and this bias coil BIC has a loop-shaped coil winding. The coil leads 9g on both ends of the wire 9f are extended in the direction of the predetermined bending portion 2a, and are connected to the coil lead connection terminal 9C shown in FIG. 4.

In addition, as shown in FIG. By etching in a pattern shape, the coil wiring board 9h, the wiring lead 98, etc. are formed, and the second base film 7a is placed via the adhesive 8, and the adhesive 8 is applied on the base film 7a. By forming a copper thin film through the coil and etching it into a loop pattern and shape as shown in FIG. Both end sides penetrate the second base film 7a and are connected to the coil wiring leads 9h through through-holes, and a cover film 10 is adhered to the upper surface of these through an adhesive 8 made of the same material as described above. A bias coil BIC is formed.

In this case, this bias coil BIC was constructed with a two-layer wiring structure consisting of a so-called three-layer structure formed on a layer above the formation layer of the wiring glue 98, etc. described above, but a laminated structure with more than that is formed. It is also possible to configure

According to such a configuration, since the bias coil BIC is integrated into the substrate FPC, it is not necessary to provide a new independent bias coil and to assemble it, and the number of parts and assembly man-hours are reduced. Furthermore, when configured as a shield case SHI assembly, the overall shape can be made even thinner and smaller.

〔Effect of the invention〕

As explained above, according to the present invention, the bias magnetic field coil is patterned around the magnetic bubble memory element of the flexible substrate on which the magnetic bubble memory element is mounted, thereby reducing the number of parts and assembly man-hours, and improving productivity. Moreover, an extremely excellent effect can be obtained in that a magnetic bubble memory device with improved reliability and a smaller and thinner overall shape can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing the whole magnetic bubble memory device according to the present invention, FIG. 2A is a bottom view, FIG. 2B is a sectional view taken along line 2B-2B of FIG. 3, and FIG. 3 is a stacked structure. Figure 4 is a diagram explaining the board FPC, Figure 5 is an exploded perspective view showing the
The figure shows board assembly B with chip CHI mounted on the board FPC.
FIG. 6 is a plan view showing the chip CHI, FIG. 7 is a diagram explaining the glue bonding of the board assembly END, FIG. 8 is a diagram explaining the magnetic circuit PFC, and FIG. 9 is a diagram showing the magnetic circuit PFC. A diagram explaining the manufacturing method of the circuit PFC, FIG. 10 is a diagram showing the inner case RFSb, and FIG. 11 is a diagram showing the outer case RF.
Figure 12 is an assembly diagram of case RFS, Figure 1 shows Sa.
3 is a sectional view of an assembly in which the board assembly BND and the magnetic circuit FPC are housed in the case RFS, FIG. 14 is a diagram explaining the configuration of the magnet body BIM, FIG. 15 is a diagram explaining the bias coil, Figure 16 is a cross-sectional view of the case RFS assembly incorporating a pair of magnets BIM and bias coil BIC, and Figure 17 is the outer shield case S H
The figure showing I a, Fig. 18 is the inner shield case 5HI
Figure 19 is an assembly diagram of the shield case SHI, and Figure 20 is an assembly diagram of the shield case SHI shown in Figure 16.
21 is a diagram showing the packaging case PKG; FIG. 22 is a diagram explaining the configuration of the terminal fixing plate TEF; FIG. 23 is a diagram showing the configuration of the contact pad; FIG. 24 is a cross-sectional view of the chip CHI,
Figure 25 shows the configuration of the magnetic bubble detector of chip CHH, and Figure 26 shows the magnetic bubble generator G of chip CHI.
A diagram showing the configuration of EN, FIG. 27 is a diagram showing the configuration of swap gate SWP of chip CHI, and FIG. 28 is a diagram showing the configuration of swap gate SWP of chip CH.
Figure 29 showing the configuration of the replicate gate REP of I.
Figure A shows the relationship between the bias magnetic field Hb and the holding magnetic field Hdc, Figure B shows the total rotating magnetic field Hr', Figure 30 shows the overall circuit of the magnetic bubble memory board, and Figure 31 shows the rotating magnetic field. It is a distribution characteristic diagram. FIG. 32 is a diagram showing a modification of the present invention in which a bias coil is provided on the FPC. CHI...magnetic bubble memory chip (element), FPC
...Flexible wiring board (board), BND...board assembly, CO work...drive coil (coil), COR
...Picture frame-shaped core (core), 6O-PFC...magnetic circuit, RFS...rotating magnetic field confinement case (case), RFSa...outer case, RFS
b...Inner case, BIM...Magnet for generating bias magnetic field (magnet), BIMa...Top magnet, BIM
b...lower magnet, 1NM...inclined plate, MAG...
・Permanent magnet plate (magnetic plate), HOM...Magnetic shunt plate, IN
N...Nonmagnetic gradient plate, BIG...Bias magnetic field generation coil (bias coil), SHI...External magnetic shield case (shield case), 5HIa...-
Outer shield case, 5HIb...Inner shield case, PKG...Packaging case, TEF...
Terminal fixing plate, GNP...Contact pad, 1...
Element mounting section, 2, 2a, 2b. 2c, 2d... bending portions, 3, 3a, 3b. 3c, 3d...External connection terminal connection section, 4, 4a. 4b---opening, 5, 5a, 5b, 5C---perforation,
6... Board protrusion, 7... Base film, 8...
・Adhesive, 9a... Wiring lead, 9b... External terminal, 9C... Connection terminal, 9d... Symbol, 9e...
・Index mark, 9f...Coil winding, 9g・
...Coil lead, 9h...Coil wiring lead, 10
...Cover film, 11...Tin plating layer, 12.
...Opening, 3...Solder plating layer, 14...Bonde ink hat, 15...Gold bump, 20a, 20b,
20G, 20d... Helix coil, 2]-a, 2
1-b...Connection point, 22a...X coil, 22b...
... Y coil, 23... Magnetic core, 24... Tap, 25... Wide groove, 26... Small width groove,
30... Drawing part, 3]... Bending part, 32...
Notch part, 33... constricted part, 34... bent part,
35... Notch portion, 36... Polyimide film,
37...Adhesive, 38...Coil winding, 40...
Winding wire, 51... Flat part, 52... Bent part, 53
... recessed part, 54... notch part, 55... flat part,
56...Bending portion, 57...Concave portion, 58...Notch portion, 59...Concave portion, 60...Resin plate, 61...
・Through hole, 62...Non-through hole, 63...Mark, 6
4...Opening, 65...Groove, 66...Corner, 70...
... elemental piece, 71 ... nickel plating layer, 72 ... gold plating layer. rn l+ faction ゛n -O +t-ba Figure 14 C 1-LIM INNNN 1st
6i Surface stand 1 Fig. 17 A Fig. 18 A Fig. 18 B GA: (:, C1- Fig. 22 A Fig. 22 B Fig. 22 C C0- o->W) Table U-1 Procedural amendment (method) to Showa 6 August 26th

Claims (1)

[Claims] A magnetic bubble memory element mounted on a flexible substrate is disposed in a space formed by a frame-shaped core coiled so that sets of opposing windings are parallel to each other, and the coil, core, and magnetic bubble memory element are mounted on a flexible substrate. 1. A magnetic bubble memory characterized in that the entire element is sandwiched within a case made of a highly conductive material, and a bias magnetic field coil is patterned around the magnetic bubble memory element on the flexible substrate.