Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – With contact or lead
Reexamination Certificate
2003-05-16
2004-02-24
Clarke, Jasmine (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
With contact or lead
C257S687000, C257S666000, C257S684000
Reexamination Certificate
active
06696753
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based on and incorporates herein by reference Japanese Patent Application No. 2002-142745 filed on May 17, 2002.
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device package in which a device mounted on a resin casing is electrically connected to a lead insert molded in the resin casing using a bonding wire.
A proposed semiconductor device package of
FIG. 8
is manufactured by: forming a resin casing
20
by injecting resin into a mold, in which a lead frame has already been placed; mounting a sensor device
10
; and electrically connecting the sensor device
10
to each lead
40
of the lead frame at the bonding surface
41
thereof by wire bonding using bonding wires
50
. For example, the sensor device
10
includes a diaphragm-type semiconductor pressure sensor chip
11
and a stage.
12
as a single unit. The sensor chip
11
is bonded to the stage
12
, and the sensor device
10
is fixed onto a device-mounting surface
21
of the resin casing
20
using, for example, an adhesive.
As shown in
FIG. 9A
, after a resin casing
20
is formed using a mold K
1
, the resin casing
20
is released from the mold K
1
by pushing the resin casing
20
with a movable ejector pin P
1
of the mold K
1
along the direction shown with an arrow in the circular area AA. In this instance, as shown in
FIG. 9B
, flashes B
1
are formed on a device-mounting surface
21
of the resin casing
20
, at which the resin casing
20
is pushed by the movable ejector pin P
1
. The flashes B
1
are unavoidable because the flashes B
1
are formed by the resin seeping into the clearance between the ejector pin P
1
and the mold K
1
, which is needed for allowing the ejector pin P
1
to smoothly move.
There are demands that the resin casing
20
be as small as possible. Therefore, it is not possible to provide dedicatedly an area at which the resin casing
20
is pushed by the ejector pin separately from the device-mounting surface
21
. For this reason, the resin casing
20
has been pushed by the ejector pin P
1
at an area close to the lead frame or on the device-mounting surface
21
of the resin casing
20
when the resin casing
20
is released from the mold K
1
.
However, if an area near the lead frame is pushed by the ejector pin P
1
for releasing the resin casing
20
, the lead frame becomes tilted to worsen in flatness or lift off from the resin casing
20
. As a result, the subsequent wire bonding process becomes adversely affected. On the other hand, if the device-mounting surface
21
is pushed by the ejector pin P
1
for releasing the resin casing
20
, flashes B
1
are created on the device-mounting surface
21
, and, as shown in
FIG. 10
, the sensor device
10
subsequently gets mounted over the flashes B
1
. As a result, the sensor device
10
becomes tilted when mounted, and wire bonding is no longer possible without removing the flashes B
1
. For this reason, an extra step is needed to remove the flashes B
1
after the resin casing
20
is molded, despite the added work.
The inventors of the present invention have studied this issue and have prototyped a semiconductor device package of
FIGS. 11A and 11B
. In the device package of
FIGS. 11A and 11B
, a resin casing
20
has a recessed
21
a
in a device-mounting surface
21
. When the resin casing
20
is released from a mold in its manufacturing process, the resin casing
20
gets pushed by an ejector pin at the bottom of the recess
21
a
. As a result, as shown in
FIG. 11B
, flashes B
1
are confined in the recessed
21
a
, and the sensor device
10
of the device package of
FIGS. 11A and 11B
would not come in contact with the flashes B
1
. Consequently, the sensor device
10
would no longer tilt due to the flashes B
1
.
However, if a bonding pad
15
is located above the recessed
21
a
, another problem arises as described below. When the bonding pad
15
is wire bonded, a bonding tool presses a wire
50
to the pad
15
using ultrasonic vibration. Since the sensor device
10
is lifted above the resin casing
20
at the portion right above the recessed
21
a
, the sensor device
10
could tilt or shift during the wire bonding. As a result, the ultrasonic power to be used for the wire bonding may get dissipated, and the wires
50
may not be properly bonded. That is, preferable wire bondability may not be secured at the bonding pad
15
.
Each bonding surface
41
of the leads
40
needs to be exposed from the resin casing
20
because the leads
40
are wire bonded at the bonding surfaces
41
. However, if a mold resin seeps onto and attaches to the bonding surfaces
41
when the lead frame is insert molded, preferable wire bondability may not be secured at the bonding surface
41
, either.
Thus, a semiconductor device package, in which a device mounted on a resin casing is,electrically connected to a lead insert molded in the resin casing with a bonding surface exposed using a bonding wire, has the above problems with wire bonding, if a bonding pad is located right above a recess as in the proposed semiconductor device package of
FIGS. 11A and 11B
or if a mold resin seeps onto and attaches to a bonding surface of a lead when a lead frame, from which the lead is formed, is insert molded.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above aspects with an object to enhance the wire bondability in a semiconductor device package in which a device mounted on a resin casing is electrically connected to a lead insert molded in the resin casing using a bonding wire.
To achieve the object, a first semiconductor device, package according to the present invention includes a semiconductor device, a resin casing, a plurality of leads, and a plurality of bonding wires. The semiconductor device includes a plurality of bonding pads. The resin casing has a device-mounting surface. The device-mounting surface has a recess. The semiconductor device has been mounted on the device-mounting surface. Each of the leads has a bonding surface. Each of the leads has been insert molded in the resin casing such that the bonding surface is exposed from the resin casing. Each of the bonding wires electrically connects each of the bonding pads and each of the bonding surfaces. Each of the bonding pads and the recess have a positional relation such that the semiconductor device is supported by the device-mounting surface right below the bonding pads when the bonding pads are wire bonded using the bonding wires. Therefore, it is possible to prevent the semiconductor device from tilting or shifting when the bonding pads are wire bonded using the bonding wires.
To achieve the object, a second semiconductor device package according to the present invention includes a semiconductor device, a resin casing, a lead, and a bonding wire. The semiconductor device includes a bonding pad. The resin casing has a device-mounting surface. The semiconductor device has been mounted on the device-mounting surface. The lead has a bonding surface and a burr. The bonding wire electrically connects the bonding pad and the bonding surface. The burr is located at an edge of the bonding surface. The burr has functioned as a barrier to prevent a molten resin from seeping onto the bonding surface when the lead frame has been insert molded in the resin casing.
REFERENCES:
patent: 4369330 (1983-01-01), Pilz
patent: 5294828 (1994-03-01), Okumura
patent: 5455386 (1995-10-01), Brathwaite et al.
patent: 5679976 (1997-10-01), Nishikawa et al.
patent: 5880522 (1999-03-01), Yonemoto et al.
patent: 5889323 (1999-03-01), Tachibana
patent: 5943558 (1999-08-01), Kim et al.
patent: 5977623 (1999-11-01), Ahn
patent: 6011303 (2000-01-01), Tanaka et al.
patent: 6047604 (2000-04-01), Auburger et al.
patent: A-S56-98849 (1981-08-01), None
patent: 60-65551 (1985-04-01), None
patent: A-S61-49450 (1986-03-01), None
patent: A-H6-125019 (1994-05-01), None
Clarke Jasmine
Posz & Bethards, PLC
LandOfFree
Enhancement of wire bondability in semiconductor device package does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Enhancement of wire bondability in semiconductor device package, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Enhancement of wire bondability in semiconductor device package will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3327419