Semiconductor integrated circuit device

Details Semiconductor integrated circuit device Semiconductor integrated circuit device

1998-09-29

2001-11-27

Potter, Roy (Department: 2822)

Active solid-state devices (e.g., transistors, solid-state diode

Housing or package

With contact or lead

C257S784000, C257S786000

Reexamination Certificate

active

06323548

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor integrated circuit device, and particularly to a semiconductor integrated circuit device in which the input/output pads of a semiconductor chip and the inner leads of the frame on which the semiconductor chip is mounted are connected electrically by bonding wires.
2. Description of the Prior Art
Usually, a plurality of input/output pads are formed around a semiconductor chip. In a semiconductor integrated circuit device, such input/output pads and the inner leads of the frame on which the semiconductor chip is mounted are connected electrically, for example, by wire bonding so that the semiconductor chip can electrically communicate with circuits or devices formed or placed outside its package.
Conventionally, in a semiconductor integrated circuit device, input/output pads are arranged as shown in
FIG. 5A
; that is, input/output pads
11
a
,
11
b
,
11
c
, . . . are arranged in a line along each side of a semiconductor chip
1
, at intervals that increase toward a corner (d
1
>d
2
> . . . ). Alternatively, as shown in
FIG. 6
, input/output pads
11
a
,
11
b
,
11
c
, . . . are arranged in two lines along each side of a semiconductor chip
1
, at regular intervals (d is constant).
On the other hand, as shown in
FIG. 7
, a typical frame has, with respect to each side of the semiconductor chip
1
, inner leads
23
arranged in an area wider than the area in which the input/output pads are arranged (this will hereafter be referred to as “radial arrangement of the inner leads”).
This causes the input/output pads that are arranged closer to a corner to form smaller wire angles &thgr; (i.e. the angles that the wires
3
a
,
3
b
, . . . ,
3
m
,
3
n
, . . . form with respect to the corresponding side of the semiconductor chip
1
). As a result, if, as shown in
FIG. 5B
, the input/output pads are arranged at regular intervals (d
1
=d
2
= . . . ), the distances between the wires, as measured near the semiconductor chip
1
, become shorter and shorter toward a corner (W
1
<W
2
), increasing the risk of a short circuit occurring between wires. To avoid this, in the arrangement shown in
FIG. 5A
, the input/output pads are arranged at intervals that increase toward a corner. This, however, inevitably increases the chip size.
On the other hand, in the arrangement shown in
FIG. 6
, the input/output pads are arranged in two lines and at regular intervals, and therefore, as long as the same number of input/output pads are arranged, the arrangement of
FIG. 6
requires a smaller chip size than those of
FIGS. 5A and 5B
. However, the use of a typical frame, in which the inner leads are arranged radially, causes the wire angles to become smaller and smaller toward a corner until, as indicated by arrow Y in
FIG. 6
, two adjacent wires
3
a
and
3
b
, which are connected to an outer pad
11
a
and an inner pad
11
b
respectively, cross each other.
This can be avoided by varying the wiring heights of adjacent wires. This, however, increases the thickness of the semiconductor integrated circuit device as a whole. It should be noted that an increase in thickness is as undesirable as an increase in area. Incidentally, the arrangement shown in
FIG. 6
is very effective in cases where sufficiently large wire angles &thgr; can be secured for all pads, though a special arrangement of the inner leads
23
is required on the part of the frame to secure sufficiently large wire angles &thgr; for all pads.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a semiconductor integrated circuit device in which a semiconductor chip of a minimal size can be used and in which, nevertheless, a typical frame having inner leads arranged radially can be used without increasing the thickness of the semiconductor integrated circuit device as a whole.
To achieve the above object, according to the present invention, in a semiconductor integrated circuit device in which a plurality of input/output pads formed on a semiconductor chip and a plurality of inner leads formed on a frame on which the semiconductor chip is mounted are connected electrically by wire bonding, the plurality of input/output pads are arranged in such a way that the normal from any input/output pad to at least one of the wires, or imaginary extension lines thereof, adjacent to the wire connecting that input/output pad to the corresponding inner lead has a predetermined length.
In this arrangement, for example by arranging the input/output pads in such a way that the length of the above normal is kept minimal as long as wire bonding can be performed without interference, it is possible to realize a semiconductor integrated circuit device in which a semiconductor chip of a minimal size can be used and in which, nevertheless, a typical frame having inner leads arranged radially can be used without increasing the thickness of the semiconductor integrated circuit device as a whole.


REFERENCES:
patent: 5757082 (1998-05-01), Shibata
patent: 5801450 (1998-09-01), Barrow
patent: 60-147126 (1985-08-01), None
patent: 6-168978 (1994-06-01), None
patent: 8-279527 (1996-10-01), None

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