JPS6113316B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic bubble memory devices, and more particularly to improvements in induced electrostatic noise cancellation.

Generally, when a perpendicular magnetic field is applied to a magnetic thin film whose magnetic domains have a perpendicular easy axis of magnetization, bubble domains with a diameter of several μm or less are formed at a certain magnetic field strength. Since this bubble domain can move freely within the magnetic thin film depending on the gradient of the magnetic field, it is used as a memory element in a magnetic bubble memory device. Conventionally, such a magnetic bubble memory device has a perspective view of the inside of the device shown in FIG.
It is constructed as shown in the sectional side view of the device in the figure. That is, in FIGS. 1 and 2, a magnetic bubble memory chip 1 mounted on an insulating substrate 2 has control patterns formed thereon for generating, transferring, detecting and erasing bubbles, and The electrodes are respectively connected to terminal patterns 3 for external extraction on the front side provided on the sides of the insulating substrate 2. In addition, an X-direction coil 4 and a Y-direction coil 4 are used to surround the chip 1 and provide a rotating magnetic field necessary for bubble transfer.
directional coils 5 are provided, each coil 4
and 5 are fitted onto the insulating substrate 2 so that the chip 1 is located in the center thereof. A plurality of external leads 7 penetrated through the side wall of a frame-shaped molded body 6 are soldered to each terminal pattern 3 of the insulating substrate 2, and the coils 4 and 5 are provided with bubbles in the vertical direction. Permanent magnets 8 and 9 and magnetic shunt plates 10 and 11 that apply a bias magnetic field of
The entire structure is inserted into a magnetic shield case 12 which also serves as a yoke.

Note that FIG. 3 shows an insulating substrate 2 on which a chip 1 is mounted.
1 is a plan view of the surface of the chip 1, in which the electrodes of the chip 1 are connected to a terminal pattern 3 via a conductor pattern 13, and a ground pattern 14 is provided on the conductor pattern 13 via an insulating layer. Note that both ends of the ground pattern 14 are connected to the front surface ground terminal pattern 3-1 to prevent noise due to electrostatic induction from being applied to the bubble detection signal via the conductor pattern 13.

In such a magnetic bubble memory device, the number of terminal patterns 3 on the insulating substrate 2 increases as the memory capacity of the chip 1 increases. If the insulating substrate 2 were made larger due to an increase in the number of them, the entire magnetic bubble memory device would become larger. For this reason, the increase in the number of terminal patterns 3 has been dealt with by narrowing the width of the terminal patterns 3 compared to conventional methods.
At this time, in order to obtain sufficient soldering strength between the terminal pattern 3 and the external lead 7, the terminal pattern 3
is also extended to the back side of the insulating substrate 2 to expand the soldering connection area.

As shown in FIG. 4, a terminal pattern 3' on the back side having a predetermined connection area for soldering is provided on the back side 2' of an insulating substrate 2 on which a chip 1 is mounted. Some devices are connected to a conductor pattern 13 on the surface of the substrate via a conductor layer formed on the side surface of the substrate. but,
In a magnetic bubble memory device equipped with such an insulating substrate 2, the earth pattern 14 shields noise from the terminal pattern 3 on the front side, but the terminal pattern 3' on the back side is shielded from the X coil (4 in FIG. 1). Noise based on voltage changes in the applied drive current (for example, triangular wave current) is applied to the bubble detection terminal pattern 3-2', resulting in a disadvantage that the electrical characteristics of the magnetic bubble memory device are impaired.

The purpose of the present invention is to eliminate the above-mentioned drawbacks, and this purpose is to provide a device in which, among a plurality of terminal patterns provided on the back side of the insulating substrate, the ground pattern on the back side is drawn out from the ground terminal pattern and is the bubble detection terminal pattern. This is achieved by providing a magnetic bubble memory device characterized by forming a pattern so as to surround the magnetic bubble memory device.

The present invention will be described below with reference to FIG. 5, which shows the back side of an insulating substrate according to an embodiment of the present invention.

In FIG. 5, reference numeral 20 denotes an insulating substrate on which the magnetic bubble memory chip 1 is mounted, and on both left and right sides of the back side, there are a plurality of back side terminal patterns 21, that is, a plurality of bubble detection terminal patterns 21-2. A ground terminal pattern 21-2 and a plurality of other terminal patterns 21-3 are patterned. These terminal patterns 21 are connected to the substrate 20
A part of the conductor pattern extends to the substrate surface through the side surface of the substrate, and is connected to one end of the conductor pattern (13 in FIG. 3) on the substrate surface through the front side terminal pattern 3, and the other end of the conductor pattern is connected to the chip 1. is connected to a predetermined electrode. And ground terminal pattern 21-
A ground pattern 24 bent into a substantially L-shape in plan view is drawn out from 2, and is patterned so as to surround a terminal pattern group consisting of a plurality of bubble detection terminals 21-1.

In this way, the insulating substrate 20 on which the chip 1 is mounted and the necessary circuit connections are made is assembled together with other device components by the same conventional means, and is assembled in the same manner as shown in FIGS. 1 and 2. A magnetic bubble memory device is completed, and the ground pattern 24 from the ground terminal pattern 21-2 on the back side is arranged so as to partition between the bubble detection terminal pattern 21-1 and the X-direction coil 4. Therefore, as shown in FIG. 6, a bridge circuit is constructed by the detection magnetoresistive elements R ₁ and R ₂ and the dummy magnetoresistive elements R ₃ and R ₄ , and the connection point between the elements R ₁ and R ₂ is and Omoteko R ₃ and R ₄
Detector D is connected between the connection points of element _R1 and
In a magnetic bubble memory device having a circuit with the other end of _R3 grounded, the output waveform of detector D when a predetermined current (triangular wave current) is passed through the X-direction coil is the conventional configuration shown in FIG. 7a. The noise signal component p observed in the
It is decreasing.

In the above embodiment, only the bubble detection terminal pattern 21-1 is surrounded by the earth pattern 24. However, in order to enclose other terminal patterns 21-3 in directions other than the X and Y directions,
It should be noted that there is no problem in patterning the ground pattern 24.

As explained above, according to the present invention, electrostatic noise due to C coupling between the drive coil and the bubble detection terminal on the back side of the substrate is not added to the bubble detection waveform, making detection easier and improving accuracy. The practical effects obtained are remarkable.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the basic internal configuration of a magnetic bubble memory device, FIG. 2 is a side sectional view of the device, and FIG. 3 is an insulating device with a conventional structure that is incorporated into the device with a magnetic bubble memory chip mounted on the surface. A front view of a board (an example), FIG. 4 is a back view of a conventional insulating board equivalent to the above board with a terminal pattern formed on the back side (an example), and FIG. 5 is a magnetic bubble according to an embodiment of the present invention. Figure 6 is a back view of an insulating substrate for a memory device, and an example of bubble detection circuit connection for a magnetic bubble memory device.
FIG. 7 is an example showing detected waveforms before and after the present invention is applied to the magnetic bubble memory device having the circuit shown in FIG. 6. In the figure, 1 is a magnetic bubble memory chip, 2 and 20 are insulating substrates, 3, 3', and 21 are terminal patterns, 3-1 and 21-2 are ground terminal patterns, and 21-1 is a bubble detection terminal pattern. ,1
4 and 24 are ground patterns on the front side and the back side.

Claims (1)

[Claims] 1 A magnetic bubble memory chip is mounted on an insulating substrate covered with a drive coil, and electrodes such as a bubble generator and a bubble detector formed on the chip are connected to external leads formed on the front side of the insulating substrate. A ground pattern is connected to a plurality of surface-side terminal patterns for soldering connections via conductor patterns, and covers the conductor patterns with an insulating layer on the surface of the insulating substrate. In a magnetic bubble memory device formed by connecting to a ground terminal pattern, the terminal pattern is connected to a plurality of back side terminal patterns formed on a back side of the insulating substrate through a side surface of the insulating substrate. Further, a back side ground pattern is formed on the back side of the insulating substrate, and is drawn out from the ground terminal pattern of the back side terminal patterns and surrounds at least the bubble detection terminal pattern of the back side terminal patterns. A magnetic bubble memory device characterized by: