JPH0473720B2 - - Google Patents

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. .

(Prior technology) Conventionally, flat package type electronic circuit units have been used as card-sized thin electronic circuit units on wiring boards.
IC or bare IC chip mounted as is,
The structure used is that the front and back sides are covered with insulating covers, and then thin metal plates are layered on both sides.

Card-type electronic circuit units with low power consumption memory chips such as CMOS mounted as IC chips are designed by providing through-holes in the wiring board.
It is known to have a structure in which a coin-shaped battery is mounted in the battery backup.

(Problems to be Solved by the Invention) However, in such a battery backup type card type electronic circuit unit, not only is there a small area in the thickness direction where circuit elements can be mounted, but also the thickness of the coin type battery is small. is about 1.6mm
Since it is quite thick, it has the disadvantage that the overall thickness becomes thicker.

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. It has been difficult to increase the memory capacity of memory cards in which memory chips are mounted as elements.

The present invention has been made to solve these problems, and an object of the present invention is to provide a battery-backed thin 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, and the paper battery is A metal cap is covered and hermetically sealed so that the inner surface is in contact with the negative electrode of the paper battery and the peripheral edge is in contact with the ring-shaped conductor pattern.

(Function) In the card-type electronic circuit unit of the present invention, a paper battery is inserted between a wiring base and a metal cap, and its positive and negative electrodes are connected to a power supply potential conductor pattern formed on the wiring base and ground. The circuit elements are battery-backed up by being connected to the potential conductor patterns, so that the horizontal area in which the batteries can be mounted does not decrease.

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.

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

(Example) Hereinafter, an example of the present invention shown in the drawings will be described.

FIG. 1 is a cross-sectional view showing one embodiment of the card-type electronic circuit unit of the present invention, FIGS.
The figure is an enlarged perspective view of a wiring board constituting the wiring base of the embodiment.

In these figures, reference numeral 1 indicates a wiring board based on an insulating base material such as ceramic, and a plurality of stepped non-through holes 2 are formed on the surface of the board for mounting active elements such as IC chips. A die bonding pad 3 and a wire bonding pad 4 are formed at the bottom and step of the stepped non-through hole 2, 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 almost the entire surface of the ring-shaped conductor pattern 6 except for the stepped non-through hole 2 inside the ring-shaped conductor pattern 6 is formed with a 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 in 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 bonded to the wire bonding pads. 4 and is connected by a bonding wire 9 such as an Au wire.

On the wiring base 10 having such a structure,
A cap 11 made of a metal such as Kovar or Fe/Ni42 alloy having a coefficient of thermal expansion approximately equal to that of the ceramic constituting the wiring board 1 is covered. This metal cap 11 has its peripheral end fixed to the ring-shaped conductor pattern 6 with a conductive adhesive 12 such as solder, and the inside thereof is hermetically sealed.

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

In the card-type electronic circuit unit of the embodiment configured as described above, an extremely thin paper battery 13 is placed between the metal cap 11 and the wiring base 10.
Since the active element 8 is inserted, the mounted active element 8 can be battery backed up without increasing the overall thickness.

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 mounted embedded inside 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. becomes.

In the above embodiment, an example was described in which the conductor pad 5 for attaching an 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 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 same 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 (1)

[Claims] 1. A conductor pattern with a ground potential is formed on the periphery of one side of a plate-shaped wiring substrate in which various circuit elements are embedded, and a conductor pattern with a power supply potential is formed almost entirely inside the 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 conductor pattern, and a paper battery is placed on the paper battery so that its inner surface is in contact with the negative electrode of the paper battery and its peripheral edge is in contact with the negative electrode of the paper battery. A card-type electronic circuit unit, characterized in that the ring-shaped conductor pattern is covered with a metal cap and hermetically sealed so as to be in contact with the ring-shaped conductor 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 mounted in each of these non-through holes. A card-type electronic circuit unit according to claim 1.