JPH0646512B2 - Method for evaluating characteristics of magnetic bubble memory - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a magnetic bubble memory, and more particularly to a magnetic bubble memory suitable for thinning, downsizing and low power consumption.

[Background of the Invention]

A magnetic bubble memory device that has been put into practical use in recent years is for generating a rotating magnetic field composed of rectangular solenoid coils having an asymmetric structure on a wiring substrate such as an E-shaped ceramic or synthetic resin on which a magnetic bubble memory chip is mounted. The structure is such that the X coil and the Y coil are respectively inserted and orthogonally arranged to be assembled. The X coil and the Y coil are not only the magnetic bubble memory chip but also a structure in which a wiring board much larger than the chip is wound, so that the length of each coil becomes long, and the driving voltage and power consumption increase. Will end up. Further, since the X coil and the Y coil are required to have a uniform inductor balance in order to apply a uniform and stable in-plane rotating magnetic field to the magnetic bubble memory device, the coil shapes thereof are different from each other and have an asymmetric structure and a large structure. I had no choice. Further, a pair of permanent magnet plates for applying a vertical bias magnetic field to the magnetic bubble memory element and its magnetic compensating plate are arranged on the outer surfaces of these X and Y coils, and their peripheral portions are covered with a resin mold. This structure increases the vertical stack thickness, which is an obstacle to the demand for thinner and smaller magnetic bubble memory devices.

The prior art closest to the present invention known to the applicant of the present invention is Japanese Patent Application Publication No. 55129 of 1979. This publication describes the structure of a frame-shaped core surrounding a chip and a conductive magnetic field reflection box completely surrounding them.
However, no further concrete structure is shown, and it is theoretically impossible to make electrical connection to the chip completely surrounded by the conductor case without shorting it from the outside of the conductor case. It is possible, and it is insufficient from a viewpoint to think that the description will be put into practical use, including the fact that the method of attaching the permanent magnet, the magnetic shunt plate, the bias coil, etc. is unclear. That is, the embodiments of the present invention happened to coincide with the description of the above publication in that the frame type cores are used as a result.

[Object of the Invention]

An object of the present invention is to provide a method capable of measuring a holding magnetic field margin of a thinned magnetic bubble memory.

[Outline of Invention]

The present invention is to measure the operating margin of the holding magnetic field by arranging the solenoid coil SOC outside the rotating magnetic field confinement case RFS and passing a current Id through it. According to the present invention, the magnetic bubble memory described below is used. A method for characterization of is provided.

A magnetic bubble memory device mounted on a flexible substrate is arranged in a space formed by a frame-shaped core in which coils are arranged so that pairs of windings facing each other are parallel to each other. A solenoid coil for holding the entire element in a case of a good conductive material and applying a DC magnetic field parallel to the surface of the magnetic bubble memory element is arranged in the vicinity of the case of a good conductive material, and is fed to the solenoid coil. A characteristic evaluation method for a magnetic bubble memory, wherein the operating margin of a holding magnetic field is measured by operating the magnetic bubble memory while gradually increasing a current value.

Example of Invention

 Next, an embodiment of the present invention will be described with reference to the drawings.

First, the magnetic bubble memory to which the present invention is applied (applied) will be described with reference to FIGS. 1 to 31, and then the third embodiment.
Characteristic portions of the present invention will be described with reference to FIGS. 2 to 36.

(Outline of Overall Structure FIGS. 1 and 2) FIGS. 1 and 2A and 2B are Japanese Patent Application No. 60-66456 (Japanese Patent Application Laid-Open No. 61-227286), which is a prior application by the present applicant. 2 is a diagram for explaining the entire structure of a magnetic bubble memory to which the characteristic evaluation method according to the present invention is applied, which is disclosed in FIG. 1, FIG. 1 is a partially cutaway perspective view, and FIG. 2A is a bottom view thereof. FIG. 2B is a sectional view taken along line 2B-2B of FIG. 2A. In these drawings, CHI is a magnetic bubble memory chip (hereinafter referred to as a chip). In these drawings, the chip CHI is omitted and only one chip is shown, but in this example, two chips are arranged side by side. To do. (The chip yield is better with a multi-divided chip configuration that matches the total storage capacity than with one large-capacity chip). The FPC is a flexible wiring board (hereinafter referred to as a board) on which two chips CHI are mounted and which has wire group extensions for connecting the chips CHI and external connection terminals at four corners. COI has two chips C
A drive coil (hereinafter referred to as a coil) that surrounds the HI on substantially the same plane and is arranged so that the opposite sides are parallel to each other, and COR is a fixed arrangement provided so as to penetrate the hollow portion of the rectangular coil assembly COI. A frame-shaped core (hereinafter referred to as a core) made of a soft magnetic material, and the core COR and each coil COI configure a magnetic circuit PFC that applies an in-plane rotating magnetic field to the chip CHI. RFS is a rotating magnetic field confinement case (hereinafter referred to as a case) that houses the central square portion of the substrate FPC, the two chips CHI and the magnetic circuit PFC as a whole. The case RFS is formed by processing two independent plates, and the upper and lower plates are electrically connected at the side surface of the case. A narrowed portion is formed in the peripheral portion so that the gap in the central portion is narrowed in a range slightly wider than the portion where the chip CHI is arranged. This narrowed portion can also be used for positioning the magnet body. Case RF
S has the effect and function of two birds with one stone that confine the magnetic field and mechanically support the weak substrate FPC.

Between the case RFS and the chip CHI, especially the chip C
Although there is a gap SIR on the side surface of the HI, the gap SIR, including the flat portion of the chip CHI, is coated or filled with silicone resin, so that foreign matter may adhere to the main surface of the chip during assembly or moisture may be removed after assembly. The passivation effect is intended to reduce penetration into the main chip surface or side surfaces. If complete airtight sealing can be performed outside the case RFS, the filling of the resin SIR may be omitted. INM is a pair of inclined plates made of a magnetic material arranged on the outside of the case RFS. In FIG. 2, the upper inclined plate INM is closer to the left and the lower inclined plate INM is closer to the right. Both of them have an inclined surface on the case RFS side. As the material of the inclined plate INM, soft ferrite or permalloy having a high magnetic permeability μ and a small coercive force Hc may be used. In this example, soft ferrite which is easy to process the inclined surface was selected.
The MAG is a pair of permanent magnet plates (hereinafter referred to as magnet plates) arranged inside the pair of inclined plates INM so as to be superposed thereon. The HOM is a pair of magnetic compensating plates made of a magnetic material such as soft ferrite and arranged inside each of the magnet plates MAG so as to overlap with each other. The magnet plate MAG is formed to have a uniform plate thickness over the entire surface. The INN is a pair of inclined plates made of a non-magnetic material having good thermal conductivity, such as copper, which is arranged on the inner facing surfaces of the pair of magnetic shunting plates HOM so as to be superposed thereon. These inclined plates INN are formed to have an inclined angle substantially equal to that of the inclined plate INM and an inclined surface in the opposite direction. The inclined plate INM, the magnet plate MAG, the magnetic shunt plate HOM, and the inclined plate INN are stacked and arranged, respectively, and integrated to form a bias magnetic field generating magnet body BIM (hereinafter referred to as a magnet body).
Is formed so that the entire laminated plate magnet body has a uniform thickness over substantially the entire surface. The pair of magnet bodies BIM are bonded to the central flat portion surrounded by the narrowed portion of the case RFS. The BIC is a bias magnetic field generating coil (hereinafter referred to as a bias coil) arranged in a groove-shaped gap portion between the peripheral portion of the magnet body BIM and the case RFS. The bias coil BIC is driven to adjust the magnetic force of the magnet plate MAG according to the characteristics of the chip CHI or to test all the bubbles of the chip CHI when testing for the presence or absence of a defective bubble generation defect.
The SHI is a case RFS housing a substrate FPC on which the chip CHI is mounted and a magnetic circuit PFC, and an external magnetic shield case (hereinafter referred to as a shield) made of a magnetic material housing a pair of magnet bodies BIMa, BIMb and a bias coil BIC on the outside thereof. It is called a case). As a material for the shield case SHI, a magnetic material having a high magnetic permeability μ, a large saturation magnetic flux density Bs, and a small Hc is preferable. Permalloy and ferrite have such characteristics, but in this example, they are suitable for bending. , A permalloy iron-nickel alloy that is strong against mechanical external force was selected. The PKG is a packaging case made of a material such as Al, which is attached to the outer peripheral surface of the shield case SHI by adhesion or fitting and has a high thermal conductivity and is easy to process. The CNP is a contact pad that extends from the four corners of the substrate FRC and that is arranged so as to come into contact with the external connection terminal that is arranged so as to come into contact with the external connection terminal that is folded back on the back surface of the shield case SHI. . TEF is a terminal fixing plate made of an insulating member that supports and fixes each contact pad CNP at the stepped portion of the opening.

(Characteristics of Overall Structure, FIGS. 1 and 2) Features of the overall structure of the magnetic bubble memory device shown in FIGS. 1 and 2 are listed as follows. However, the features of this example are not limited to these, and other features will be apparent from the description of FIG. Describe the features.

(1) Since the rotating magnetic field generating coil PFC is of a frame type and the bubble memory chip CHI is arranged on the substantially same plane within the frame, the thickness of the entire bubble device can be reduced. This is because in the current mainstream technology, the upper and lower surfaces of the chip are wound around by the X and Y coils, and the total 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 Y coil are arranged on substantially the same plane, the following effects are obtained as compared with the conventional structure in which the Y coil is wound on the X coil.

The total winding length of the coil does not become long. Therefore, the inductance L can be reduced, and low voltage driving and low power consumption can be achieved.

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

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

(4) The conductor case RFS includes the rotating magnetic field Hr generating coil P.
The AC magnetic field generated from the FC is prevented from leaking to the magnet body BIM having a large magnetic permeability μ while the DC magnetic field of the bias magnetic field Hb to be applied from the magnet body BIM to the chip CHI is substantially prevented. There is the option of not having it.

(5) Since the conductor case RFS is made of a material such as copper, which is harder than epoxy glass or the like which has been conventionally used as a wiring board, the chip CHI can be mechanically and firmly supported. Therefore, especially in the case of a multi-chip mounting structure for increasing the manufacturing yield, the variation in the inclination angle between chips has a great influence on the magnetic characteristics, but according to this example, the variation in the inclination angle between chips is small. It is held down.

(6) Flexible film substrate FPC as wiring substrate
The following effects are obtained by using.

The substrate thickness can be reduced.

Since the lead bonding method can be adopted, the thickness occupied by the bonding portion can be reduced as compared with the conventional wire bonding method.

The above effect is due to the gap of the magnetic circuit (permeability μ
The bias magnet MAG having a small thickness or a small plane area can be used, which leads to thinning of the entire device or reduction of the plane area.

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

The width of the wiring extraction opening of the rotating magnetic field confinement case RFS can be reduced. Therefore, leakage of the rotating magnetic field can be minimized.

(7) Since the externally derived wirings of the wiring board FPC are gathered in the respective rectangular portions, the opening of the rotating magnetic field confinement case RFS can be provided at the corner having the least influence.

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

A material such as copper having good workability can be used to form the inclination angle.

A material such as copper having a high thermal conductivity can be used, and the heat generated by the rotating magnetic field generating coil COI can be efficiently dissipated.

By using a non-magnetic material, the magnetic shunt plate HO
The magnetic field passing through M can be prevented from being disturbed.

(9) The inclined plate INN is preferably as thin as possible in order to reduce the magnetic gap, and is thin by limiting the width thereof to a position necessary and sufficient for forming the inclination angle as compared with the magnet MAG and the magnetic shunt plate HOM. It makes it easy to form an angle of inclination.

(10) Since the plate INM such as soft ferrite having a large magnetic permeability μ is inserted between the magnet MAG and the shield case SHI, the magnetic gap between them can be filled. The plate INM also contributes to heat dissipation. Board IN
Since a material having a holding force Hc smaller than that of the magnet MAG is selected as M, the effective thickness of the permanent magnet can be kept uniform.

(11) Since the shield case SHI is made of a magnetic material such as permalloy having a high magnetic permeability μ, the magnetic resistance of the magnetic circuit using the magnet MAG as a magnetic field source can be reduced, so that the thickness and the plane area of the magnet MAG can be reduced. it can.

(12) Since the shield case SHI is made of a magnetic material such as permalloy having a high saturation magnetic flux density Bs, it has a function of bypassing external magnetic field noise and not transmitting it to the chip CHI.

(13) The above (11) and (12) are shield case SH, respectively.
This leads to the reduction of the thickness of I.

(14) The shield case SHI is made of iron such as permalloy.
Since it uses a nickel alloy, it is suitable for bending work and also has a function of protecting the components incorporated therein against external mechanical force.

(15) Rotating magnetic field generating coil PFC and bias coil BI
Since both C are core type, it is possible to increase the storage efficiency or the mounting density in the packaging case SHI or PKG.

(16) Case R is placed between the core-COR and the magnetic shunt plate HOM.
Since the FS is inserted, the distance can be finely adjusted by the thickness and the bending angle of the rotating magnetic field confinement case RFS in addition to the thickness of the coil COI. The shorter this distance is, the smaller the planar size of the whole can be made, which leads 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 leaks to the core-COR having high magnetic permeability,
The uniformity of the bias magnetic field in the peripheral portion of the chip becomes poor. Therefore, this distance is very severe in view of the above characteristics, and according to this structure, the adjustment can be performed precisely.

(17) Since the diaphragm is provided around the rotating magnetic field confinement case RFS, the magnet body BIM can be easily aligned.

(18) The inclined plate INN is made of two pieces under the same manufacturing conditions. By arranging them so that there is a rotation angle difference of 180 ° on the upper and lower surfaces of the chip, the upper and lower surfaces of the chip are sandwiched. A pair of magnetic compensating plates HOM and a pair of magnets MAG arranged
Can be aligned almost parallel.

The features of the overall structure of the magnetic bubble memory shown in FIGS. 1 and 2 have been described above, but there is a modified example described later for the solenoid coil for measuring the holding magnetic field (FIG. 32). The features will be described below.

(19) By providing the solenoid coil SOC on the outside of the rotating magnetic field confinement case RFS, the chip CHI can be obtained by supplying a direct current to the solenoid coil SOC.
Since it is possible to generate a DC magnetic field parallel to the plane of, the holding magnetic field can be measured.

(Outline of Assembly FIG. 3) FIG. 3 is an assembly perspective view for explaining a stacking and assembling procedure of each constituent member constituting the above-described magnetic bubble memory device, and the same reference numerals as those used above denote the same members. . In the figure, first, a substrate F having projecting portions at four corners and connecting portions for input / output wiring and an element mounting portion at the central portion
Board assembly board BN with 2 chips CHI mounted on PC
D is an outer case R in which an insulating sheet is adhesively arranged on the bottom surface.
After the magnetic circuit PFC is installed on the substrate FPC and the magnetic circuit PFC is installed on the substrate FPC, silicone resin SIR (not shown) is filled and the inner case RFSb is installed on the upper case RFSa to the outer case RFSa. The side contact portion with the inner case RFSb is electrically connected by soldering or the like. Next, after arranging the upper magnet body BIMa and the lower magnet body BIMb in the concave throttle portions provided on the outer surfaces of the outer case RFSa and the inner case RFSb, the outer edge portion of the upper magnet body BIMa and the inner case RFSb are arranged. Bias coils BIC wound in alignment with each other are arranged in a gap (not shown) formed with the inside of the case, and these are housed in the outer case SHIa.
b inside, outer case SHIa and inner case SHI
The side contact portion with b is magnetically connected by welding or the like.
Next, the external connection terminal connecting portions of the board FPC protruding from the four corners of the inner case SHIb are connected to the inner case SHIb.
As shown in FIG. 4B, it is folded back behind b and arranged in combination so as to have a constant shape. Each external connection terminal covered with solder or the like provided on each of these connection portions is connected to a contact (not shown). A terminal fixing plate TEF having a pad CNP mounted in each opening is disposed in contact with each other, and each external connection terminal and the contact pad CNP are electrically connected by soldering or the like by thermocompression bonding or the like. Next, these assembled bodies are housed in a packaging case PKG, and the terminal fixing plate T
At the contact portion between the EF and the packaging case PKG, a hermetic seal or the like is sealed for assembly.

Next, the structure of each component described above will be described.

(Flexible Wiring Board FIG. 4) FIG. 4 is a view showing a board FPC, FIG. A is a plan view thereof, and FIG. 4B is a view in which the connecting portions of the external connection terminals protruding from the four corners are folded and combined. The plan view, FIG. C is an enlarged sectional view of 4C-4C in FIG. A, and FIG. D is 4D- in FIG.
It is a 4D enlarged sectional view. In the figure, the substrate FPC is
The element protection portion 1 having a square shape at the center, the bent portions 2 (2a, 2b, 2c, 2d) having a small width at the four corners, and the external connection terminal connection portion having a square shape (hereinafter referred to as a connection portion) at the tip portion thereof. 3) (3a, 3b, 3c, 3d), and the overall shape is substantially windmill-shaped and integrally formed.
Rectangular openings 4 (4a, 4b) having a double frame structure for mounting two chips CHI, which will be described later, on the opposite sides of the element protection part 1 and connecting the terminals thereof, and three holes for positioning. 5 (5a, 5b, 5c) are provided, and a substrate projecting portion 6 for positioning is provided at the tip of one connecting portion 3c.

In addition, as shown in FIG. 1C, this substrate FPC has a copper thin film 9 (hereinafter referred to as a wiring layer) on a base film 7 made of a polyimide resin film having a thickness of, for example, about 50 μm via an epoxy adhesive 8. When collectively called, it is expressed as 9,
When each part is shown, a subscript is added to 9) is formed, and this is etched into a desired pattern shape, so that wiring leads 9a, circular external terminals 9b, as shown in FIG. Elliptical coil lead connection terminal 9c,
Patterns such as symbols 9d and index marks 9e are formed, and a light-transmitting or semi-light-transmitting cover film 10 is adhered and arranged on the upper surface of the patterns through an adhesive 8 made of the same member as described above. And this substrate FP
In the opening 4 of C, the base film 7 on the chip CHI mounting side (not shown) is formed with a highly precise size, and the upper cover film 10 has a relatively large size. Further, the wiring lead 9a is exposed between the base film 7 and the cover film 10, and the tin plating layer 1 is formed on the surface of the wiring lead 9a.
1 is formed, and the opening shape has a double-layer structure and a double frame structure. On the other hand, in the connection portion 3, a circular opening 12 is formed in a portion of the cover film 10 corresponding to the circular external terminal 9b and the oval external terminal 9c (not shown) as shown in FIG. 12
A solder layer 13 formed by plating or dipping is formed on the copper thin film patterns of the external terminals 9b and 9c exposed from. The external terminals 9b and 9c provided on these connecting portions 3 are connected to the connecting portions 3a, 3b, 3c and 3d and the bent portions 2a, 2b, 2c and 2d and the element protecting portion 1.
The wiring leads 9a are connected to the wiring leads 9a continuously formed on the upper surface of the device mounting portion 1. The wiring leads 9a are connected to the connecting portions 3 at a part of the opening ends of the opening portions 4a and 4b provided in the element mounting portion 1.
The blocks a, 3b, 3c, and 3d are gathered together, and their tips are exposed in the openings 4a and 4b. That is, as shown in FIG. 3A, the wiring lead 9a of the connecting portion 3a is located in the upper left portion of the opening 4a, the wiring lead 9a of the connecting portion 3b is located in the lower left portion of the opening 4b, and the wiring lead 9a of the connecting portion 3c.
Is wired in the upper right part of the opening 4a, and the wiring lead 9a of the connection part 3d is wired in the lower right part of the opening 4b. Then, this substrate FPC will be used for each connection portion 3 in a later step.
a, 3b, 3c and 3d are bent portions 2a, 2b and 2
The external terminals 9b and 9c on which the solder layer 13 is formed by being bent at c and 2d and combined as shown in FIG. 9B are exposed on the surface, and the wiring leads 9a, the symbol 9d and the index mark 9e are on the surface. Since they are covered with the cover film 10, these patterns are configured so that they can be easily judged through the cover film 10.

In such a structure, the substrate FPC is made of a polyimide resin film, and the bent portions 2 are provided at the four corners of the element protection portion 1.
Each connecting portion 3a, 3b, 3 via a, 2b, 2c, 2d
c and 3d are provided in the shape of a wind turbine, and each of these connecting portions 3
Since the external terminal portion is formed by folding back and combining a, 3b, 3c, and 3d, the element protection portion 1 and the connection portion are separated from each other.
Because of the layered wiring structure, the area of the element protection portion 1 can be increased without reducing the area of the connection portion 3, and at the same time, the external terminal portion can be multi-terminaled and the overall shape can be reduced. .

Further, in such a configuration, the wiring lead 9a from each external terminal 9b to each opening 4a, 4b of the element protection portion 1
Can be significantly shortened, so that the influence of external noise or the like can be greatly reduced. That is, a signal having a high S / N ratio can be input / output. Further, the board protruding portion 6 is provided at one end of the connecting portion 3c, and the index mark 9e is provided on the protruding portion 6, so that the central portion of the board for display and cases RFS and SHI when folded and assembled.
(As shown in FIG. 2) It can be easily used by the identification for alignment, the type of the wiring lead 9a, or the product type display when it is assembled in (see FIG. 2), so that the assembly and the board management are rationalized. can do. Also, the substrate FP
By providing the perforations 5a, 5b, 5c on both end sides of the element protection portion 1 of C, the left and right of the substrate FPC can be distinguished, and the chip CH
Positioning of I, etc. becomes easy, and similarly, the assembling property can be rationalized.

(Substrate Assembly FIGS. 5, 6 and 7) FIG. 5 is a plan view showing the chip CHI mounted on the above-mentioned substrate FPC. In the figure, the substrate FPC
Two chip CHIs are provided in the element mounting portion 1 of the opening 4a,
Substrate assembly BND is configured by being mounted in parallel between 4b, and one of the chips CHI is constituted by integrating two blocks of 1Mb chips as shown in an enlarged plan view of FIG. Two chips CHI make up four blocks, that is, a total of 4 Mb chips. In one block of the chip CHI shown in FIG. 6, thick lines indicate conductor patterns and thin lines indicate chevron pattern transfer paths. The chip CHI shown in FIG. 5 has bonding pads 14 formed by gold plating on the ends of the chip CHI and the substrate FPC as shown in the enlarged sectional views of FIGS. 7A and 7B. The gold bumps 15 are interposed between the openings 4 and the disposing leads 9a on which the tin-plated layer 11 is formed, and are mounted by lead bonding using Au-Su eutectic by a thermocompression bonding method.

According to such a configuration, the openings 4a, 4a of the substrate FPC are
Since the disposing lead 9a of b and the bonding pad 14 of the chip CHI are connected by lead bonding using Au-Su eutectic, the chip CHI can be supported and fixed.
The connection strength can be greatly improved and the thickness can be reduced. Further, since the surface of the chip CHI is covered by the element mounting portion 1 of the substrate FPC, the surface of the chip CHI is protected, the handling property can be improved, and the mechanical strength of the substrate FPC can be maintained. . Further, according to such a configuration, each chip CHI is made up of two blocks and two chips CHI are made up of four blocks. Therefore, each block is closest to each of the connection portions 3a, 3b, 3c, Wiring can be distributed to 3d, the symmetry of the chip CHI arrangement can be obtained, and testing, inspection, etc. are extremely easy. Further, since four connecting portions 3a, 3b, 3c, 3d are provided on the board FPC, each chip C
The wiring of the HI magnetic bubble detector DET and the map loop, etc. is distinguished from other functional wiring in one connection part, and this connection part is selected and arranged at a part away from the noise source to thereby reduce noise. It is possible to send and receive input / output signals with extremely small number.

(Driving Magnetic Circuit FIGS. 8 and 9) FIG. 8 is a diagram showing a magnetic circuit PFC, FIG. A is a perspective view, and FIG. 8B is a plan view showing the driving magnetic circuit. In the figure, the magnetic circuit PFC has four sets of coils 20a, 20b, 20 in which windings are applied in the arrow direction on mutually parallel opposing sides of a frame-shaped core COR made of a soft magnetic material.
A coil COI composed of c and 20d is wound, and coils 20a and 20b on opposite sides are wound in series via a connection point 21b to form an X coil 22a and a coil 20c.
And 20d are wound in series via the connection point 21a to form the Y coil 22b. Then, by supplying currents Ix and Iy (for example, triangular wave currents) whose phases are different by 90 degrees to the X coil 22a and the Y coil 22b, the leakage magnetic field Hx in the x-axis direction as shown in FIG.
A leakage magnetic field Hy is generated in the y-axis direction and is supplied to the above-mentioned two chips CHI as a rotating magnetic field.

Further, in the magnetic circuit PFC configured as described above, as shown in a perspective view in FIG. 9, windings are tapped in blocks of a plurality of blocks in a rectangular parallelepiped magnetic core 23 made of one soft magnetic material.
Are provided and wound in series to form a pair of coils, for example, the coil 20.
After forming a pair of X coils 22a composed of a and 20b, a wide groove 25 having a constant width and a narrower groove 26 are provided by cutting between the coils 20a and 20b. Thereafter, the groove 26 having a small width is cut, and the wide groove 25 divided into both is combined and bonded in a direction orthogonal to each other to form a frame shape as shown in FIG. On the contrary, the coils 20a and 20b may be wound via the taps 24 around the rectangular parallelepiped core 23 in which the wide groove 25 and the narrow groove 26 are formed in advance to form the pair of X coils 22a. . Further, 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 around the rectangular parallelepiped magnetic core 23 by providing the taps 24 in the serial direction. Therefore, when the coils 20a and 20b are assembled as shown in FIG. It is not necessary to make a connection point) and the winding of the winding can be simplified.

According to such a configuration, the X coil 22a and the Y coil 2
Since it has a symmetrical structure with 2b, it becomes a coarse coupling,
The inductance balance is improved, and magnetic interference between the magnetic bodies with respect to the leakage magnetic field can be prevented. Further, since this magnetic circuit PFC has a frame-shaped structure which is not arranged on the upper and lower surfaces of the chip CHI, the thickness in the stacking direction becomes small, and the thickness can be reduced.

(Rotating magnetic field confinement case, FIGS. 10, 11 and 12) FIG. 10 is a view showing the inner case RFSb.
Is a plan view and FIG. 9B is a sectional view taken along line 10B-10B.
In the figure, the inner case RFSb includes a frame-shaped narrowed portion 30 having a concave central portion, a bent portion 31 having its opposite end sides bent upward by approximately 90 degrees, and four corners thereof in an oblique direction. The case RFSb is formed by pressing a highly conductive material such as an oxygen-free copper plate. In this case, the narrowed portion 30 and the bent portion 31 improve the mechanical strength in the twisting direction of the inner case RFSb, and can appropriately limit the outer diameter dimension L in the vertical and horizontal directions between the bent portions 31 facing each other. . Further, the diaphragm portion 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.
The cutouts 32 provided at the four corners are the case RF.
Each of the bent portions 2a, 2 of the substrate FPC arranged in Sb
B, 2c, 2d lead-out portions are formed.

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

Although oxygen-free copper is used for the inner case RFSb, a plate material obtained by plating a copper, silver, gold plate or an alloy plate of these may be used instead.

FIG. 11 is a view showing an outer case RFSa corresponding to the above-mentioned inner case RFSb. FIG. 11A is a plan view and FIG. 11B is a sectional view taken along line 11B-11B. In the figure,
The outer case RFSa is the inner case RFS described above.
It is formed by the same material and manufacturing method as b, and its structure is the frame-shaped narrowed portion 33 whose central portion is concave and the opposite end sides thereof are bent upward by approximately 90 degrees in the same manner as described above. The bent portion 34 and the four corners of the bent portion 34 are provided with notches 35 cut obliquely.
In this case, the bent portions 34 facing each other have inner dimensions substantially equal to the outer dimensions L1 and L2 between the bent portions 31 of the inner case RFSb described above, and the height H1 is increased. Is formed. The narrowed portion 33 and the cutout portion 35 are formed to have substantially the same dimensions as the inner case RFSb described above.

The outer case RFSa and the inner case RFSb thus configured are shown in FIG. 12A in a plan view and FIG. 12B.
12B-12B, the inner case RFSb is inserted into the outer case RFSa, and the outer surface of the bent portion 31 of the outer case RFSa is brought into contact with each other to be connected to each other, whereby the case RFS is assembled. To be

(Case assembly FIG. 13) FIG. 13 shows the board assembly BND in the case RFS described above.
FIG. 6 is a cross-sectional view in which the components are stored and arranged. In the figure, on the bottom surface of the outer case RFSa, a polyimide film 36 having a thickness of, for example, about 0.1 mm is adhesively arranged as an electrically insulating sheet, and the board assembly BND, and A magnetic circuit FPC is provided around the periphery.
, And an epoxy adhesive 37 is applied to the upper surface of the board assembly BND, and the inner case RFSb is inserted and joined to the upper portion of these. 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 to each other by a metal flow or soldering at a portion indicated by X. The gap between the outer case RFSa and the inner case RFSb is filled with silicone resin SIR, and the board assembly BND and the magnetic circuit PFC are fixedly arranged. In this case, these outer case RFSa and inner case RF
Notch portions 32 (not shown) provided at the four corners of Sb,
35 is a bent portion 2 (2a, 2b, 2) of the substrate FPC.
c, 2d) is pulled out to the outside. 38 is a coil CO
I is a lead wire for connecting the terminals or for connecting the coil COI and the external terminal 9c provided on the substrate FPC.

In such a configuration, when a leakage magnetic field is generated by driving the magnetic circuit FPC, an induced current flows in the case RFS so as to form a closed loop, and the rotating magnetic field is confined in the case RFS by the induced current. Is given a uniform rotating magnetic field.

With such a configuration, the substrate F is provided in the central concave portion between the outer case RFSa and the inner case RFSb.
Since the chip CHI mounted on the PC is arranged with the magnetic circuit PFC sandwiched between the convex portions of the peripheral portion, the packaging effect can be improved and the assemblability can be greatly improved. Further, since the volume covered by the outer case RFSa and the inner case RFSb is reduced, V
The I product (∝ volume) can be reduced, and the magnetic circuit PFC that generates the rotating magnetic field can be downsized. Outer case R
By providing concave portions formed by the narrowed portions 30 and 33 on the FSa and the inner case RFSb to reduce the gap between the concave portions facing each other, the component (Z component) perpendicular to the plane of the chip CHI in the rotating magnetic field becomes zero. Only the horizontal components are close to each other, and the uniformity can be improved.

(Magnet Body FIG. 14) FIG. 14 is a diagram showing a magnet body BIM, FIG. A is a plan view, FIG. B is a side view thereof, and FIG. C is a front view thereof.
In the figure, the magnet body BIM has a slant plate IN made of a non-magnetic material, for example, copper, one of the facing surfaces of which has a predetermined slant surface.
N, a first magnetic compensating plate HOM ₁ having a uniform thickness and arranged on the inclined surface side of the inclined plate INN, and the first magnetic compensating plate HOM ₁
Magnet plate MAG having a uniform plate thickness, which is disposed on the upper surface side of the magnet plate, and the second magnetic shunt plate H having an inclined surface on the upper surface side of the magnet plate MAG.
OM ₂ and OM ₂ are sequentially laminated and are integrally formed by an epoxy adhesive, and the overall laminated plate thickness is made uniform over almost the entire surface. Then, a uniform magnetic field for generating a bias magnetic field is emitted from the upper and lower surfaces of the magnet body BIM over substantially the entire surface.

(Bias Coil FIG. 15) FIG. 15 is a diagram showing a bias coil BIC, FIG. A is a perspective view, and FIG. 15B is a sectional view taken along line 15B-15B. In the drawing, the bias coil BIC is a winding coil 40 whose surface is covered with, for example, a thermosetting resin as an insulating member, and is wound in an array so that the entire shape is a frame shape with a cross section of 5 × 4 lines. After that, it is pressure-bonded by heat welding, cooled, and formed into a frame shape having a predetermined value. In this case, the thermosetting resins coated on the outer surface of each winding wire 40 are heat-welded to each other, and each winding wire 40 is clogged and formed by pressure bonding, and is cooled, whereby each winding wire 4 is wound.
Since 0 is hardened in a bound state, it is formed into a frame shape having a predetermined shape.

(Mounting magnet and bias coil to case assembly
FIG. 16) FIG. 16 is a sectional view showing the case RFS assembly described in FIG. 13 and the magnet body BIM and bias coil BIC described above incorporated therein. In the figure,
An upper magnet body BIMa lower magnet body BIMb is adhesively arranged on the upper and lower surfaces of a case RFS assembly that accommodates a board assembly BND and a magnetic circuit PFC inside, and a peripheral portion of the upper magnet body BIMa and an inner case. RFS
The bias coil BIC is housed in the frame-shaped groove formed by being surrounded by the bent portion 31 of b. In this case, the upper magnet body BIMa and the lower magnet body BIMb are made of exactly the same material and size, and these magnet bodies BIMa and BIMb are surrounded by the narrowed portion 30 of the inner case RFSb on the inclined plate INN side. The concave portion and the concave portion surrounded by the narrowed portion 33 of the outer case RFSa are arranged in close contact with each other.

In such a configuration, a pair of magnet bodies BIMa, is formed in the concave portion formed on both sides of the central portion of the case RFS assembly.
The BIMb is arranged, and the bias coil BIC can be arranged in the frame-shaped groove formed in the peripheral portion of the BIMb.
The overall thickness of each component in the stacking direction is reduced, which enables downsizing and thinning. Further, since the frame-shaped space groove is formed between the outer case RFSa and the outer edge portion of the lower magnet body BIMb, the bias coil BIC may be arranged in this portion, or a new bias coil may be provided. Further, it is also possible to form a bias coil by winding a coil bobbin.

(Magnetic Shield Cases 17, 18, and 19) FIG. 17 is a view showing the outer shield case SHIa, FIG. A is a plan view, and FIG. 17B is a sectional view taken along line 17B-17B. In the figure, the outer shield case SHIa
Is a flat portion 51, a bent portion 52 that is folded upward at an angle of approximately 90 degrees to the opposite end side of the flat portion 51, and a recessed portion 53 that is partially cut away in the central portion of the bent portion 52.
Each of the four corners is configured to have a notch 54 that is cut in an oblique direction, and this shield case SHIa has a high magnetic permeability and a high saturation magnetic flux density, and preferably has a high thermal conductivity. For example, it is formed by pressing a permalloy plate.

FIG. 18 is a view showing an inner shield case SHIb corresponding to the outer shield case SHIa described above. FIG. 18A is a plan view and FIG. 18B is a sectional view taken along line 18B-18B. In the figure, this inner shield case SHIb
Is formed by the same material and manufacturing method as the above-mentioned outer shield case SHIa, and the structure thereof is substantially the same as that described above, and the flat portion 55 and the opposite end sides of the flat portion 55 are folded back upward by approximately 90 degrees. A bent portion 56, and a recessed portion 57 that is partially cut away in the center of the bent portion 56,
Each of the four corners has a notch portion 58 cut obliquely. In this case, the bent portions 56 facing each other have an outer dimension between them which is substantially equal to the inner dimension L3, L4 between the bent portions 52 of the outer shield case SHIa described above, and the height H2 is made smaller. Is formed.

The outer shield case SHIa and the inner shield case SHIb thus constructed are shown in FIG. 19A, a plan view thereof, and FIG. 19B, a sectional view taken along line 19B-19B thereof, respectively. Insert SHIb, outer shield case SHI
The recess 53 of a and the recess 57 of the inner shield case SHIb
The outer shield case SHIa is assembled by spot-welding or solder-welding the recessed portions 59 formed by and magnetically and mechanically fixing them to integrate them.

In such a configuration, the outer shield case SHIa
The folded portion 52 and the folded portion 56 of the inner shield case SHIb are set in the laminating direction without being set in the lateral direction, that is, the direction intersecting the laminating direction, thereby reducing the dimension in the lateral direction and reducing the size. In addition, high integration of constituent parts is possible.

(Magnetic shield case assembly FIG. 20) FIG. 20 shows the above-mentioned shield case SHI assembly.
FIG. 16 is a sectional view showing a case RFS assembly in which the substrate assembly BND and the magnetic circuit FPC are incorporated, and an assembly including a pair of magnet bodies BIMa and BIMb and a bias coil BIC as described in FIG. It is a thing.
In the figure, inside the outer shield case SHIa, from the bottom side to the upper magnet body BIMa in the central part, the bias coil BIC in the peripheral part, the case RFS assembly (the board assembly BND, the magnetic circuit PFC, etc. are incorporated inside). The lower magnet body BIMb is sequentially laminated and arranged,
The inner shield case SHIb is inserted and welded and fixed by a recess 59 (see FIG. 19) formed by the recess 53 of the outer shield case SHIa and the recess 57 of the inner shield case SHIb described above. In this case, by filling the inside of this shield case SHI with grease or the like, the internal components substantially come into close contact with each other, and the heat generated from the case RFS is transferred to the outside via this shield case SHI. Can be released to. Further, the case RFS and the shield case SHI can be made to have a structure in which they are brought into contact with each other on the side surface by a press-fitting method to improve the heat dissipation effect.

In such a configuration, the outer shield case SHIa
The case RFS assembly on the bottom side of the
The outer shield case SHIa and the inner shield case SH are arranged by stacking the first and the second stacks so that they face each other.
Since each of the components laminated with Ib can be arranged in close contact with each other, it is possible to make the device compact and thin, and at the same time obtain a heat dissipation effect.

(Packaging Case FIG. 21) FIG. 21 is a view showing a packaging case PKG, in which FIG. A is a plan view and FIG. B is a sectional view taken along the line 21B-21B. In the figure, the packaging case PKG
Is formed by drawing an aluminum plate having a good thermal conductivity, for example, an aluminum plate having a plate thickness of about 0.5 mm, and a black coating film is provided on the outer surface thereof, which is not shown. This packaging case PKG is the outer shield case S
The shape of HIa can be improved and used in combination.

In such a configuration, this packaging case P
The KG serves as an outer case after completion of the magnetic bubble memory device and has a function as a heat radiator, and further, an inner corner portion thereof also has a function as a mold at the time of resin molding by a potting method described later.

(Terminal Fixing Plate and Contact Pads FIGS. 22 and 23) FIG. 22 is a view showing the terminal fixing plate TEF, in which FIG. A is a plan view, FIG. B is a sectional view taken along line 22B-22B, and FIG. It is a rear view. In the figure, the terminal fixing plate TEF
Is made of an electrically insulating material, for example, a glass epoxy resin plate 60, and its outer shape is formed to have vertical and horizontal dimensions that can be inserted into and removed from the opening of the packaging case PKG. In addition, a large number of through holes 61 are formed in a matrix-like arrangement at predetermined intervals in the vertical and horizontal directions in a portion excluding the peripheral portion of the resin plate 60, and further at the corners of these through hole groups. Is provided with a non-through hole 62 having a concave cross section that is not rotationally symmetrical, and a mark 63 made of a white coating film or the like for positioning the directionality or the feature is attached to the non-through hole 62. Further, as shown in FIG. 3B, the large number of through holes 61 formed in the resin plate 60 are provided with openings 64 having a large diameter on the back side thereof so as to coaxially communicate with each other. All of the openings 64 have a depth of about 60% of the plate thickness and communicate with the through holes 61 with a step during coating. Further, on the back side of the resin plate 60, as shown in FIG. 6C, the resin plate 60 has a depth substantially equal to the depth of the opening 64 along its peripheral portion, and the width in the plane direction is different, and its cross section is concave. A groove 65 is formed, and the inside of this groove 65 constitutes a passage portion and a connecting portion of the winding of the coil COI and the winding of the bias coil BIC described above. Further, the corner portion 66 of the resin plate 60 does not have a concave shape, has a predetermined plate thickness dimension, and is fitted to the inner side surface of the packaging case PKG to obtain a contact surface. In this way, the back surface side of the resin plate 60 is formed to have a two-step structure with different plate thicknesses.

FIG. 23 is a view showing the contact pad CNP, FIG. 23A is a plan view, and FIG. 23B is a sectional view taken along line 23B-23B. In the figure, the contact pad CNP is a nickel-plated layer 7 formed on the surface of an element 70 obtained by punching out a highly conductive material, for example, a copper plate having a thickness of about 0.5 mm by press working.
1, a gold plating layer 72 is formed.

(Final Assembly FIGS. 20, 4, and 2) For each of the components thus configured, first, the shield case assembly described in FIG. 20 is inserted into the packaging case PKG described above. In this state, the connecting portions 3a, 3b, 3c, 3d (see FIG. 4A) of the board assembly BND are connected to the bending portions 2a, 2b, 2c, 2d from the four corners of the packaging case PKG by about 90 degrees.
Bends and protrudes. Next, resin molding is performed on the four corners of the packaging case PKG by the potting method, and the individual parts are fixedly arranged in the packaging case PKG. Continue to each of these connections 3
a, 3b, 3c, 3d corresponding bending portions 2a, 2
B, 2c and 2d are further bent at about 90 degrees and combined with the outer surface of the inner shield case SHIb via an adhesive as shown in FIG. 4B, and then the terminal fixing plate TEF
A contact pad CNP is mounted in each opening 64 on the back side, or the side surface of the contact pad CNP is further fixed by an adhesive and inserted into the packaging case PKG, and arranged in contact with each connection portion 3a, 3b, 3c, 3d. Let In this case, since the arrangement pitch of the external terminals 9b provided in the connection portions 3a, 3b, 3c, 3d and the arrangement pitch of the contact pads CNP are the same, the external terminals 9b and the contact pads CNP are the same. Make electrical contact. Next, from the back side of the terminal fixing plate TEF arranged, for example, by inserting a heating body having a thin tip into each through hole 61 and thermocompression-bonding the contact pad CNP, each external terminal 9b.
The corresponding contact pads CNP are electrically connected and the terminal fixing plate TEF is mechanically fixed at the same time to complete the magnetic bubble memory device shown in FIG.

(Magnetic Bubble Memory Element FIGS. 24, 25, 26, 27, 28) FIG. 24 is a sectional view of the magnetic bubble memory chip CHI in the vicinity of the bonding pad PAD. In the figure, GGG is gadolinium-gallium-ga.
It is a rnet substrate, LPE is a bubble magnetic film formed by a liquid phase epitaxial growth method, and an example of its composition is as shown in Table 1 below.

ION indicates an ion implantation layer formed on the surface of the LPE film for suppressing hard bubbles. SP1 is a first spacer, and for example, SiO ₂ having a thickness of 3000 Å is formed by a vapor phase chemical reaction. CON1 and CON2 are 2
2 shows a conductor layer of a layer and has a function of controlling bubble generation, copying (division) and exchange described later, the lower first conductor layer CON1 is Mo, and the upper second conductor layer CON2.
Are made of a material such as Au. SP2 and SP3 are interlayer insulating films (second and third spacers) made of a polyimide resin or the like for electrically insulating the conductor layer CON and the transfer pattern layer P such as Permalloy formed thereon. PAS is SiO formed by the vapor phase chemical reaction method.
It is a passivation film consisting of _two films. PAD indicates a bonding pad of the chip CHI, and a thin connector wire such as an Al wire is bonded thereto by a thermocompression bonding method or an ultrasonic method. This bonding pad PA
D The first layer PAD ₁ is Cr, the central second layer PAD ₂ is Au layer below the third layer PAD ₃ above are respectively formed of a material such as Au plating layer, the second layer PAD ₂ and The third layer PAD ₃ may be made of a material such as Cr or Cu. Reference symbol P denotes a layer used for a bubble transfer path, bubble division, generation, exchange and detection part, and a guardrail part, and will be referred to as a transfer pattern layer for convenience in the following description.

In the example of FIG. 24, the transfer pattern layer P is F on the lower layer P ₁ .
Although e-Si is used and Fe-Ni is used for the upper layer P ₂ , the materials of both may be interchanged.

Hereinafter, an example in which the above-mentioned transfer pattern layer composed of a plurality of layers is applied to each part of the chip CHI will be described with reference to plan views of FIG. 25 and subsequent drawings. In these plan views, each transfer pattern layer is formed by self-alignment. Note that they are represented by the same contour line. FIG. 25 shows the bubble detector D portion, and MEM is the main magnetoresistive element, and the presence or absence of bubbles is utilized by utilizing the fact that the resistance value changes when a bubble stretched in a lateral strip shape passes therethrough. To detect. The MED is a dummy magnetoresistive element having the same pattern shape as the main magnetoresistive element MEM, and is used to detect a noise component due to the influence of the rotating magnetic field and the like. Although only two stages are shown above the main magnetoresistive element MEM, several tens of bubble stretchers ST are formed to expand the bubbles in the horizontal direction and transfer the bubbles downward. Note that PR indicates the transfer direction of bubbles.
ER is a bubble eraser, and is erased when the bubble reaches the conductor layer CND. A guard rail GR composed of three rows of pattern groups is provided around the detector D and between the dummy and main detections.
Unnecessary bubbles generated in the inside of the guard rail are pushed out, and unnecessary bubbles generated outside the guardrail GR are prevented from entering the inside. In addition,
In the plan pattern diagrams of FIG. 25 and subsequent figures, the patterns other than the conductor layer CND show the transfer pattern layer P described in FIG. In the figure, by forming the magnetoresistive elements MEM and MED with a multilayer magnetic layer, the signal-to-noise ratio (S /
N ratio) was improved. For example, when a three-layer permalloy layer with a SiO ₂ film interposed between each layer is used as a transfer pattern, the S / N ratio is improved by more than 2 times as shown in Table 2 below as compared with that for a single permalloy layer. be able to.

In addition, the performance of the guardrail GR is also improved by reducing the holding force Hc and increasing the rejection rate of unnecessary bubbles.

FIG. 26 shows a magnetic bubble generator GEN. By making the transfer pattern layers P multi-layered, the generated current of the magnetic bubble can be reduced, and the life of the conductor layer CND of the magnetic bubble generator is lengthened. It became possible to do. Therefore, the drive circuit of the conductor layer CND can also use a semiconductor element having a small current capacity value, and the cost can be reduced.

FIG. 27 shows a swap gate portion formed of a write loop line MML formed by a transfer pattern row of minor loops m, Pw ₁ -Pw _3, etc. formed of transfer patterns of Pa to Ph and a hairpin-shaped conductor layer CND. Shows. In the figure, P ₇ is the bubble generator GE of FIG.
It is the same as the transfer pattern P ₇ in N, in other words, the bubble generated in the bubble generator GEN is P ₁
~ Write major line WM through P ₇ transfer path
Is transferred to L. When a current is applied to the swap conductor layer CND, the magnetic bubbles of the transfer pattern Pd of the minor loop m ₁ are transferred to the transfer pattern Pw ₃ of the major line WML through the transfer patterns Pl and Pm, and the magnetic bubbles from the major line Pw ₁ are transferred. Is the transfer pattern Pk, P
After passing through j and Pi, the data is transferred to the transfer pattern Pe of the minor loop and bubbles are exchanged, that is, information is rewritten. A swap gate is not provided in the minor loop md at the right end, but this is a dummy loop that does not inject magnetic bubbles to reduce the peripheral effect.
Thus, the transfer pattern layers Pi to Pm at the conversion position
By forming multiple layers, it is possible to exchange magnetic bubbles with a small current value.

Further, as shown in FIG. 28, a small current value can be driven in a magnetic bubble copying machine, that is, a divider. In the figure, the normal magnetic bubbles are transferred along the route of Pn to Pq and Ps to Px, and when a current is passed through the conductor layer CND, the bubbles are divided at the position of the transfer pattern Pq, and one divided magnetic field is generated. bubble Py, is transferred to the read main jar line RML through P ₈ to P _10.

(Holding magnetic field and rotating magnetic field FIG. 29) The magnet plate MAG is arranged with an inclination of about 2 degrees with respect to the chip CHI. The bias magnetic field Hb is applied to the chip CHI with a slight deviation from the vertical direction, thereby generating a holding magnetic field Hdc that improves the start and stop margins of bubble transfer by about 6 [Oe] (29th). (Figure A).

As shown in FIG. 29A, the magnet body BIM and the chip CHI
The DC magnetic field Hz has a component Hdc in the xy plane due to the inclination of the angle θ with. The magnitude of this in-plane component Hdc is Hz · sin θ, which is the normal Hdc.
The inclination angle θ is selected so as to be 5 [Oe] to 6 [Oe]. The direction of the in-plane component Hdc is the start / stop (St / Sp) direction of the rotating magnetic field Hr (+ x
It is inclined so as to match the (axial direction). The xy in-plane component Hdc is a known magnetic field called a holding field, which works effectively for the start / stop (St / Sp) operation of the rotating magnetic field Hr. The magnitude of the bias magnetic field Hb acting perpendicularly to the surface of the chip CHI is Hz · cos θ.

Since the holding field Hdc described above always acts on the xy plane of the chip CHI, the holding field Hdc is
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 CHI is a combination of the rotating magnetic field Hr ′ applied from the outside and the in-plane component Hdc, and the rotating magnetic field Hr ′.
The center O'of is moved in parallel in the + x axis direction which is the start / stop (St / Sp) direction by the in-plane component Hdc.
Therefore, as is clear from the result of FIG. 7, even if the strength of the rotating magnetic field Hr applied from the outside is | Hr |, the strength | Hr '| of the rotating magnetic field that effectively acts on the chip CHI.
Varies depending on the phase of the rotating magnetic field Hr. That is, St /
| Hr '| in the Sp direction becomes | Hr | + | Hdc |, which is a holding field Hdc compared to | Hr |
Is stronger by | Hdc |. Conversely, St / S
| Hr '| in the case of the direction opposite to the p direction is | Hr |-| Hd
c |, which is weakened by | Hdc | as compared with | Hr |.

(Peripheral Circuit FIG. 30) Finally, the peripheral circuit of the chip CHI will be described with reference to FIG.
RF is a circuit for generating a rotating magnetic field Hr by passing a current having a 90 ° phase difference through the X and Y coils of the chip CHI. S
A is a sense amplifier that samples, senses, and amplifies a minute bubble detection signal from the magnetoresistive element of the chip CHI at the timing of the rotating magnetic field. DR is MBM
This is a drive circuit for supplying a current to each functional conductor of the bubble generation and swap related to the writing of the device and the replicate related to the reading related to the device at a predetermined timing. The above circuit is synchronized by the 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 characteristic FIG. 31) FIG. 31 shows the rotating magnetic field distribution characteristic of the above-mentioned magnetic circuit PEC. That is, in the figure, the horizontal axis represents the length in the X-axis direction with the center in 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 when = 0 is shown, the rotating magnetic field distribution characteristics shown by the curve I were obtained. As is clear from the figure, a substantially uniform rotating magnetic field strength Hx is obtained up to the range of the distance −Xc + Xc to the inside between the opposing cores COR of the magnetic circuit PFC, and the effective area of the chip CHI (the rotating magnetic field is (Minimum range to be given) In the range of -Xe to + Xe, the magnetic field intensity uniformity of ± about 2% was obtained. A curve II shown by a broken line is a rotating magnetic field distribution characteristic of the conventional magnetic circuit.

(Characteristic portion of the present invention) The magnetic valve memory to which the present invention is applied has been described above. The characteristic portion of the present invention will be described below with reference to FIGS. 32 to 36.

FIG. 32 is a diagram showing the overall structure of an embodiment of the present invention in which a solenoid coil SOC for measuring a holding magnetic field is added. The SOC is a solenoid coil wound on the outer surface of the case RFS. In this case, the solenoid coil SOC is formed by inserting a coil bobbin wound by winding a fine wire on the outer surface of the case RFS with a dimensional margin. By press molding from the upper and lower surfaces, the shape is closely arranged along the outer surface of the case RFS.

FIG. 33 is a view showing a solenoid coil SOC, FIG. 33A is a plan view, and FIG. 33B is a sectional view taken along the line 33B-33B. In the figure, the solenoid coil SOC has a winding 4D having an outer surface coated with, for example, a thermosetting resin as an insulating member, and an inner diameter capable of inserting the case RFS assembly with a sufficient dimensional margin. Coil assemblies 41 are formed by aligning and winding so as to form a rectangular cylindrical shape, then bonding them by heat welding, cooling and forming into a coil bobbin shape of a predetermined value.

FIG. 34 is a sectional view showing the case RFS assembly described in FIG. 13 with the solenoid coil SOC, magnet body BIM and bias coil BIC incorporated therein. In the figure, the coil assembly 41 is inserted into the case RFS assembly that houses the board assembly BND and the magnetic circuit PFC therein, and press molding is performed from above and below to form a solenoid along the outer surface shape of the case RFS assembly. The coil SOC is closely arranged. Further, an upper magnet body BIMa and a lower magnet body BIMb are adhesively arranged on the upper and lower surfaces of the solenoid coil SOC.

In measuring the start / stop characteristics of the magnetic bubble memory device configured as described above, the magnetic bubble memory device is first driven and is arranged on the outer surface of the rotating magnetic field confinement case RFS assembly in which the chip CHI is housed. To the solenoid coil SOC
A direct current Id as shown in FIG. 5 is passed. Ir is a triangular wave current for generating a rotating magnetic field (Ix and Iy in FIG. 8A).
Corresponding to). As a result, the DC magnetic field H due to this DC current Id is applied together with the rotating magnetic field Hr to the surface of the chip CHI housed in the case RFS assembly. In this case, this DC magnetic field H is confined in the case RFS and is generated as a demagnetizing field parallel to the surface of the chip CHI and opposite to the holding magnetic field Hdc. Therefore, the DC current Id is gradually increased and applied to the extent that the chip CHI malfunctions to increase the demagnetizing field, so that the holding magnetic field Hdc in the operating area A of the magnetic bubble memory device is increased as shown in FIG. Since the operating margin ΔH can be measured and the setting value of the holding magnetic field Hdc can be obtained from this value, it is possible to easily determine whether the holding magnetic field is appropriate.

Since this solenoid coil SOC only needs to obtain a magnetic flux of up to about 100 e, the winding thickness may be thin and does not hinder the thinning and miniaturization of the magnetic bubble memory device.

Although the solenoid coil SOC is arranged outside the case RFS assembly, the same effect as described above can be obtained by disposing the solenoid coil SOC inside the case RFS assembly.

〔The invention's effect〕

As described above, according to the present invention, the magnetic bubble memory device mounted on the flexible wiring board is arranged in the space of the rotating magnetic circuit of the frame-shaped core, and the whole is confined in the rotating magnetic field of the good conductive material. Since a space for generating a leakage magnetic field can be made small by sandwiching it in a case and providing a solenoid coil on the outer surface of the case to electrically connect the peripheral edge portion, a highly uniform rotating magnetic field can be obtained with a small VI product. At the same time, the miniaturization of the rotating magnetic field confinement case results in low power consumption, a compact and thin overall shape, and a magnetic bubble memory device with guaranteed start / stop characteristics of the magnetic bubble. An extremely excellent effect can be obtained.

[Brief description of drawings]

1 is a partially cutaway perspective view showing the entire magnetic bubble memory device to which the present invention is applied, FIG. 2A is a bottom view, and FIG.
FIG. B is a sectional view taken along line 2B-2B of FIG. A, FIG. 3 is an exploded perspective view showing a stacking structure, FIG. 4 is a view for explaining a substrate FPC, and FIG. 5 is a substrate assembly in which a chip CHI is mounted on the substrate FPC. FIG. 6 is a plan view showing a three-dimensional BND, FIG. 6 is a view showing a chip CHI, FIG. 7 is a view explaining lead bonding of a substrate assembly BND, FIG. 8 is a view explaining a magnetic circuit PFC,
FIG. 9 is a diagram for explaining a method of manufacturing the magnetic circuit PFC, first
0 is a view showing the inner case RFSb, FIG. 11 is a view showing the outer case RFSa, FIG. 12 is an assembly view of the case RFS, and FIG. 13 is a case assembly in which the board assembly BND and the magnetic circuit FPC are housed. FIG. 14 is a cross-sectional view of the assembly, FIG. 14 is a view for explaining the structure of the magnet body BIM, FIG. 15 is a view for explaining the bias coil, and FIG. 16 is a case RFS assembly with a pair of magnet body BIM and bias coil BIC. FIG. 17 is a sectional view of the assembled assembly, FIG. 17 is a view showing the outer shield case SHIa, and FIG. 18 is an inner shield case S.
HIb, FIG. 19 is an assembly view of the shield case SHI, FIG. 20 is a sectional view of an assembly in which the assembly shown in FIG. 16 is incorporated in the shield case SHI, and FIG. 21 is a packaging case PKG. FIG. 22, FIG. 22 is a view for explaining the structure of the terminal fixing plate TEF, FIG. 23 is a view for showing the structure of the contact pad, FIG. 24 is a sectional view of the chip CHI, and FIG. 25 is a magnetic bubble detection of the chip CHI. 26 is a diagram showing the configuration of the device D, FIG. 26 is a diagram showing the configuration of the magnetic bubble generator GEN of the chip CHI, FIG. 27 is a diagram showing the configuration of the swap gate SWP of the chip CHI, and FIG. 28 is a replicate of the chip CHI. FIG. 29A shows the structure of the gate REP, and FIG. 29A shows a bias magnetic field Hb and a holding magnetic field Hd.
FIG. 30 is a diagram showing a total rotating magnetic field Hr ′, FIG. 30 is a diagram showing an entire circuit of the magnetic bubble memory board, and FIG. 31 is a rotating magnetic field distribution characteristic diagram. Third
Figure 2 shows solenoid coil S for holding magnetic field measurement
The figure which shows the whole structure of the Example of this invention which added OC, FIG. 33A and B are the figures which respectively show the plane and cross-section of solenoid coil SOC, and FIG. 34 is solenoid coil SO.
FIG. 35 is a diagram for explaining mounting of C, FIG. 35 is a waveform diagram of a current passed through the solenoid coil SOC, and FIG. 36 is a diagram showing a bias magnetic field margin thereof. CHI ... Magnetic bubble memory chip (element), FPC ...
... Flexible wiring board (board), BND ... Board assembly, COI ... Drive coil (coil), COR ... Frame-shaped core (core), PFC ... Magnetic circuit, RFS ... Rotating magnetic field confinement case (case) , RFSa ... Outer case, RFSb ... Inner case, BIM ... Bias magnetic field generating magnet body (magnet body), BIMa ... Upper magnet body, B
IMb ... Lower magnet body, INM ... Inclined plate, MAG ...
Permanent magnet plate (magnet plate), HOM ... magnetic shunt plate, INN ...
Non-magnetic inclined plate, BIC ... Coil for bias magnetic field generation (bias coil), SHI ... External magnetic shield case (shield case), SHIa ... Outer shield case, SHIb ... Inner shield case, PKG ... Packaging case , TEF …… Terminal fixing plate, CNP ……
Contact pad, 1 ... Element mounting part, 2, 2a, 2
b, 2c, 2d ... Bent portions, 3, 3a, 3b, 3
c, 3d ... External connection terminal connection part, 4, 4a, 4b ...
Openings, 5, 5a, 5b, 5c ... Perforations, 6 ... Substrate protrusions, 7 ... Base film, 8 ... Adhesive, 9a ...
Wiring lead, 9b ... External terminal, 9c ... Connecting terminal, 9d ... Symbol, 9e ... Index mark, 10
...... Cover film, 11 ...... tin plating layer, 12 ...... opening, 13 ...... solder plating layer, 14 ...... bonding pad, 15 ...... gold bump, 20a, 20b, 20c, 20
d ... Helix coil, 21a, 21b ... Connection point,
22a ... X coil, 22b ... Y coil, 23 ... magnetic core, 24 ... tap, 25 ... wide groove, 26
...... Narrow groove, 30 ...... Draw part, 31 ...... Bend part, 32 ...... Notch part, 33 ...... Draw part, 34 ...... Bend part, 35 ...... Notch part, 36 ...... Polyimide film , 37 ... Adhesive, 38 ... Coil winding, 40 ... Winding, 51 ... Flat portion, 52 ... Bent portion, 53 ... Recessed portion, 54 ... Notched portion, 55 ... Flat portion, 56 ... Bent portion, 57 ... Recessed portion, 58 ... Notched portion, 59 ... Recessed portion, 60 ... Resin plate, 61 ... Through hole, 62 ... Non-through hole, 63 ... Mark, 64 ... Opening, 65 ... Groove, 66
...... Corner part, 70 …… Element, 71 …… Nickel plating layer,
72 ... Gold-plated layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kazuo Hirota, Kazuo Hirota, 292 Yoshida-cho, Totsuka-ku, Yokohama City, Kanagawa Prefecture, Ltd., Production Engineering Laboratory, Hitachi, Ltd. (72) Nobuo Kishiro, 3350, Hayano, Mobara, Chiba, Hitachi Device Engineering Co., Ltd.

Claims (1)

[Claims] 1. A magnetic bubble memory device mounted on a flexible substrate is arranged in a space formed by a frame-shaped core in which coils are arranged such that sets of windings facing each other are parallel to each other, and the coil, A solenoid coil for holding the entire core and the magnetic bubble memory element in a case of a good conductive material and applying a DC magnetic field parallel to the surface of the magnetic bubble memory element is arranged in the vicinity of the good conductive material case, A characteristic evaluation method of a magnetic bubble memory, characterized in that an operating margin of a holding magnetic field is measured by operating the magnetic bubble memory while gradually increasing a current value flowing in the solenoid coil.