Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – On insulating carrier other than a printed circuit board
Reexamination Certificate
1998-10-29
2001-04-10
Potter, Roy (Department: 2822)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
On insulating carrier other than a printed circuit board
C257S700000
Reexamination Certificate
active
06215178
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly to a semiconductor device suitable as a driver LSI for a liquid crystal display (LCD).
2. Description of the Related Art
Conventionally, in order to reduce electronic modules or devices in size and cost and simplify their configurations, there is a known TCP (tape carrier package) which has a carrier tape having a device hole and wiring such as inner leads, a semiconductor element (e.g., a semiconductor chip) mounted on and electrically connected to the carrier tape, and the resin-encapsulating layer to seal the connecting portion.
Especially, for the LCD which is a thin and low-power consuming display, TCP which has a quite slim semiconductor chip mounted on a tape having a device hole smaller than the chip, and is configured to be connectable in two directions on the long sides of the semiconductor chip, is used as a driver LSI. Such TCP, which is an ultra narrow TCP, will be called UNT hereinafter.
FIG.
8
A and
FIG. 8B
show the structure of the UNT. In the drawings, reference numeral
1
shows a film carrier tape made of polyimide resin or the like. This tape has long and narrow rectangular device holes
2
. The device holes
2
are formed to have long sides and short sides, which are smaller than those of the semiconductor chip to be described afterward. The short sides are arranged in parallel with the longitudinal direction (indicated by the arrow) of the carrier tape
1
. One face of the carrier tape
1
has wiring such as a group of inner leads (not shown). Each inner lead has its leading ends protruded from two long sides of the device hole
2
.
Reference numeral
3
shows the semiconductor chip mounted in a device hole region of the carrier tape
1
. The semiconductor chip
3
is electrically connected to the inner leads through bumps of Au or the like. Furthermore, a resin-encapsulating layer
4
of epoxy resin or the like is externally formed on the surface of the semiconductor chip
3
where electrode pads are formed and the connections of the semiconductor chip
3
and the inner leads. The resin-encapsulating layer
4
is formed by a method for dispensing to apply a liquid encapsulating resin by a dispenser for example. Reference numeral
5
shows a dummy inner lead (hereinafter called the dummy lead) with its leading ends protruded from the short sides of the device holes
2
. The dummy lead
5
is connected to the electrode pad of the semiconductor chip
3
so to serve to mechanically support and fix the semiconductor chip
3
.
The conventional UNT configured as described above, however, has the device hole
2
with its long and short sides made shorter than the corresponding sides of the semiconductor chip
3
, allowing substantially no gap between the semiconductor chip
3
and the inner peripheral surface of the device hole
2
. Accordingly, the encapsulating resin dispensed onto the electrode pad-formed surface of the semiconductor chip
3
, flows to the lower face (opposite from the wiring-formed face) of the carrier tape
1
in such a small amount (expanding length) of about 200 &mgr;m from the end faces of the semiconductor chip
3
on the long and short sides. Therefore, a strength of adhesive of the resin-encapsulating layer
4
on the short sides of the semiconductor chip
3
is insufficient.
Specifically, such a semiconductor device has the carrier tape
1
die-cut on the side slightly outside of the resin-encapsulating layer
4
, bent or folded into an appropriate shape and mounted on a mother board. Therefore, the resin-encapsulating layer
4
is required to have a strength of adhesive of at least 10 N (Newton) per unit area (m
2
) against the carrier tape
1
.
But, in the conventional UNT, the resin-encapsulating layer
4
formed on the short sides of the semiconductor chip
3
has such a low strength of adhesive of
2
N/m
2
that the resin-encapsulating layer
4
is cracked in the steps of die-cutting and folding of the carrier tape
1
. As a result, the inner leads and the semiconductor chip
3
may have a defective connection or a breakage in the inner leads.
SUMMARY OF THE INVENTION
The invention was completed to remedy the problems described above. And its object includes that a strength of adhesive of the resin-encapsulating layer formed on the short sides of a semiconductor chip is improved in a semiconductor device having the UNT structure, and a crack is prevented from being caused.
Specifically, a semiconductor device of the invention comprises an insulating film having a device hole; inner leads, which are disposed on one main face of the insulating film with their leading ends protruded to the device hole; a semiconductor element, which is mounted on the device hole region of the insulating film and has its electrode pads electrically connected to the ends of the inner leads; and a resin-encapsulating layer for covering the semiconductor element, the inner leads and the connection of the semiconductor element and the inner lead, wherein a length of the device hole along its long side is determined to be larger than the corresponding long side of the semiconductor element, and the resin-encapsulating layer coated on the insulating film is largely expanded externally on the short side of the device hole as compared with that on the long side.
Such a semiconductor device is UNT and characterized in that a length of the device hole along the long side only is larger than that of the long side of the semiconductor element, and a length along the short side is smaller than that along the corresponding short side of the semiconductor element.
The insulating film used for the semiconductor device of the invention includes a polyimide resin film for example. Generally, the insulating film is desired to have a thickness of about 50 to 125 &mgr;m depending on a type, shape and size of the semiconductor device.
The invention can have the device hole having a flat shape with a projection formed to externally project in the neighborhood of the middle on the short side. This flat shape of the projection of the device hole can be a triangle or square with a part or the full length of the short side of the device hole as one side, or a semicircular or arc with a part or the full length of the short side of the device hole as the diameter or chord thereof, or a shape similar to such shapes.
The projection on the short side of the device hole has desirably a projected length of 200 to 300 &mgr;m, and more preferably 100 to 300 &mgr;m. It is desirable that an expanded length of the resin-encapsulating layer formed on the other face of the insulating film through the projections of the device hole is desirably adjusted to fall in a range of 500 to 1,000 &mgr;m (1 mm) on the short side of the semiconductor element. When the projected length on the short side of the device hole is less than 200 &mgr;m, the expanded length of the resin-encapsulating layer is less than 500 &mgr;m, resulting in insufficient strength of adhesive between the resin-encapsulating layer and the insulating film on the short side of the semiconductor element. When the projected length on the short side of the device hole exceeds 300 &mgr;m, the expanded length of the resin-encapsulating layer is larger than 1 mm. Even when the expanded length is larger than 1 mm, additional improvement of the strength of adhesive is not expected, but workability such as die-cutting of the film is degraded.
Thus, the semiconductor device of the invention has a larger length of the device hole along the long side than the corresponding length of the semiconductor element so to form a gap between the inner peripheral surface of the device hole and the semiconductor chip on the short side of the semiconductor element. Therefore, when the resin-encapsulating layer is formed by dispensing a liquid resin, the liquid resin can flow in a sufficient amount through the gap on the short side to reach the other face of the insulating film. Thus, the resin-encapsulating layer to
Fukuzawa Yuji
Goto Masao
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Kabushiki Kaisha Toshiba
Potter Roy
LandOfFree
Semiconductor device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2547308