JPS637984A - Card type electronic circuit unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a battery backup type card-type electronic circuit unit in which various circuit elements such as IC chips are densely mounted.

(Conventional technology) Conventionally, as a card-sized thin electronic circuit unit,
Flat package type IC or bare IC on the wiring board
The structure used is that the chip is mounted as is, covered with an insulating cover from both the front and back, and then a thin metal plate is layered on both sides.

A card-type electronic circuit unit that has a memory chip with low power consumption such as 0MO3 installed as an IC chip has a structure in which a through hole is provided in the wiring board and a coin-shaped battery is mounted in the hole for battery backup. (Problems to be Solved by the Invention) However, in such a battery back-up type card type electronic circuit unit, not only is there a small area in the thickness direction where circuit elements can be mounted. Since the thickness of the coin-type battery is approximately 1.6M, it has the disadvantage that the overall thickness becomes thick.

In addition, it is not possible to mount circuit elements such as IC chips on the part where the battery is mounted on the wiring board, and the horizontal mounting area is small, resulting in the problem of low packaging density. In a memory card in which a memory chip is mounted as an element, it is difficult to increase the memory capacity.

The present invention was made to solve these problems, and an object of the present invention is to provide a thin, battery-backed, card-type electronic circuit unit with high packaging density.

[Structure of the Invention] (Means for Solving the Problems) That is, the card-type electronic circuit unit of the present invention forms a conductor pattern at ground potential on the periphery of one side of a plate-shaped wiring base in which various circuit elements are embedded. Then, a conductor pattern with a power supply potential is formed over almost the entire area inside this conductor pattern with a ground potential, and a paper battery is placed on the conductor pattern with a power supply potential so that its positive electrode is in contact with the conductor pattern.
Furthermore, a metal cap is covered and airtightly sealed over the paper battery so that the inner surface contacts the negative electrode of the paper battery and the peripheral edge contacts the ring-shaped conductor pattern. It is a feature.

(Function) In the card type electronic circuit unit of the present invention, a paper battery is inserted between the wiring base and the metal cap,
Both the positive and negative electrodes are connected to a power supply potential conductor pattern and a ground potential conductor pattern formed on the wiring base, respectively, and the circuit element is backed up by a battery, and the horizontal area that can be mounted by mounting the battery is never decreases.

Furthermore, since various circuit elements are embedded within the plate-shaped wiring base, it is possible to obtain a card-type electronic circuit unit with high packaging density in the thickness direction.

Since the wiring base is covered with a metal cap, the mounted circuit elements are protected from external electrical influences.

(Example) Embodiments of the present invention shown in the drawings will be described below.

FIG. 1 is a sectional view showing an embodiment of the card-type electronic circuit unit of the present invention, FIGS. 2 and 3 are perspective views of the card-type electronic circuit unit as seen from the front and back sides, respectively, and FIG. 4 shows the wiring base of the embodiment. FIG. 2 is an enlarged perspective view of a wiring board.

In these figures, the symbol @1 indicates a wiring board based on an insulating substrate such as ceramic, and the surface thereof has a plurality of stepped non-through holes 2 for mounting active elements such as IC chips. 1, and this stepped non-through hole 2
A die bonding pad 3 and a wire bonding pad 4 are formed on the bottom and step portions, respectively. Furthermore, conductor pads 5 for attaching input/output terminals for connection to external devices are formed on the back surface.

Further, a ring-shaped conductor pattern 6 is formed around the surface of the wiring board 1, and the ring-shaped conductor pattern 6 covers almost the entire surface except for the stepped non-through hole 2 inside the ring-shaped conductor pattern 6. , a solid conductor pattern 7 is formed. The ring-shaped conductor pattern 6 and the solid conductor pattern 7 are held at a ground potential and a power supply potential, respectively.

On the die bonding pads 3 of the stepped non-through holes 2 of the wiring board 1, active elements 8 are bonded one by one with a conductive adhesive, and these active elements 8 are attached to the wire bonding pads 4. and is connected by a bonding wire 9 such as an AU wire.

A cap 11 made of a metal such as Kobarsha Fe/Ni42 alloy having a coefficient of thermal expansion substantially equal to that of the ceramic constituting the wiring board 1 is placed over the wiring substrate 10 having such a structure.

This metal cap 11 is made of a conductive adhesive 1 such as solder.
2, the peripheral end portion is fixed to the ring-shaped conductor pattern 6, and the inside thereof is hermetically sealed.

Furthermore, a very thin (about 0.5 seconds thick) paper battery 13, such as a lithium paper battery, is inserted into the thin gap between the metal cap 11 and the wiring base 10. The + side electrode of this paper battery 13 is
Solid conductor pattern 7 held at power supply potential on wiring board 1
is in contact with and electrically connected to it. Further, the − side electrode is in contact with the inner circumferential surface of the metal cap 11,
It is connected via this metal cap 11 to a ring-shaped conductor pattern 6 at ground potential.

In the card type electronic circuit unit of the embodiment configured as described above, the extremely thin paper battery 13 is inserted between the metal cap 11 and the wiring base 10, so that the overall thickness is not increased. , mounted active element 8
is battery backed.

Further, by mounting the paper battery 13 in this manner, the horizontal area in which the active element 8 can be mounted does not decrease, and it is possible to mount the active element 8 with high density.

Furthermore, since the active element 8 is embedded in the wiring board 1, the mounting area in the thickness direction of the wiring board 1 is utilized to the maximum, resulting in extremely high packaging density. Become something.

In the above embodiment, an example was described in which the conductive pad 5 for attaching the input/output terminal for connection to an external device was formed on the back surface of the wiring board 1, but the present invention is not limited to such an example. These mounting conductor pads 5 can also be provided on the surface of the wiring board 1 outside the metal cap 11.

[Effects of the Invention] As is clear from the above description, in the card-type electronic circuit unit of the present invention, a battery can be mounted without increasing the thickness, and circuit elements such as IC chips can be mounted with high efficiency. Can be implemented in high density.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the card-type electronic circuit unit of the present invention, FIG. 2 is a perspective view of the same as seen from the front side, FIG. 3 is a perspective view of the card-type electronic circuit unit as seen from the back side, and FIG. FIG. 2 is an enlarged perspective view of a wiring board constituting the wiring base of the example. 1...Wiring board 2...Stepped non-through hole 5...Conductor pad for attaching input/output terminals 6...
... Ring-shaped conductor pattern 7 ... Solid conductor pattern 8 ... Active element 11 ... Metal cap 13 ... Paper battery

Claims (2)

[Claims] (1) A conductor pattern with a ground potential is formed on the periphery of one side of a plate-shaped wiring base in which various circuit elements are embedded, and a conductor pattern with a power supply potential is formed over almost the entire inside of this conductor pattern with a ground potential. , a paper battery is placed on the conductor pattern at the power supply potential so that its positive electrode is in contact with the paper battery, and the inner surface is in contact with the negative electrode of the paper battery, and the peripheral edge is in the ring shape. A card-type electronic circuit unit characterized by being formed by covering and airtightly sealing a metal cap in contact with a conductive pattern. (2) The wiring base has a stepped non-through hole for mounting an active element or a stepless non-through hole for mounting a passive element, and the active element or passive element is inside each of these non-through holes. A card-type electronic circuit unit according to claim 1 mounted therein.