Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – On insulating carrier other than a printed circuit board
Reexamination Certificate
2001-05-24
2003-01-21
Wojciechowicz, Edward (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
On insulating carrier other than a printed circuit board
C257S690000, C257S692000, C257S693000
Reexamination Certificate
active
06509631
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a semiconductor device in which a semiconductor chip or an electrical component such as a chip capacitor is stacked on another semiconductor chip having a different function, and to a liquid crystal module provided with such a semiconductor device.
BACKGROUND OF THE INVENTION
The conventionally available TCP (Tape Carrier Package) is an example of a semiconductor package for use in liquid crystal driving drivers.
For example, FIG.
11
and
FIG. 12
show a TCP as a semiconductor device in which a semiconductor chip
112
is mounted in a device hole
121
a
which is formed at a predetermined position of a polyimide substrate
121
which is provided as an insulating base material tape.
The semiconductor chip
112
is electrically connected, via bumps
13
made of gold (Au), to inner leads
124
on the signal input side and inner leads
125
on the signal output side which project into the device hole
121
a
, on the opposite side of the surface of the polyimide substrate
121
where a conductive wiring (inner leads
124
and
125
and outer leads
126
and
127
) is formed.
On the wiring pattern of the inner leads
124
and
125
and the outer leads
126
and
127
is formed an organic insulating film as a solder resist
122
to be patterned in a predetermined manner. Further, as shown in
FIG. 12
, surrounding the bonding portion between the semiconductor chip
112
and the inner leads
124
and
125
is a sealant
130
made of insulating resin.
Incidentally, with the wide spreading of portable phones in recent years, the TCP has been used as a semiconductor package for a driver (liquid crystal driver) for driving a liquid crystal used in portable phones. Such a liquid crystal driver for portable phones has been mass-produced by employing a semiconductor device which includes an SRAM in a single semiconductor chip, or a semiconductor device with a dual-function of a segment driver and a common driver.
However, a problem associated with installing the SRAM or the segment and common drivers in a single semiconductor chip is that the size of the entire semiconductor chip is increased. Further, when the semiconductor chip employs the common driver in particular, the voltage used in the common driver becomes relatively high, and this requires a high voltage resisting capability, which makes the application of a fine process difficult.
Further, as the portable phone liquid crystal module is made compatible with color display or fine-pitch display, the number of outputs is increased in the segment driver and the common driver. In this case, while the chip size can be reduced by a fine process on the SRAM side, manufacture by a fine process is impossible on the side of the common driver and the segment driver because they include a logic circuit. That is, the segment driver or common driver is preferably manufactured by a rough process of about 0.5 &mgr;m, and the driver size cannot be reduced.
Further, since the semiconductor chips are manufactured from a single wafer process, the semiconductor chips need to employ the rough process as a whole, which is suitable for manufacture of the common driver and the segment driver. Thus, when a single semiconductor chip is to include the SRAM or the segment and common drivers, the chip size of the semiconductor chip is increased, resulting in increase in cost.
Further, driving of the liquid crystal module requires peripheral components, other than the liquid crystal driver, such as a chip capacitor. Such a peripheral component mounted on a carrier tape increases the size of the TCP itself, and, in turn, the size of the liquid crystal module.
Further, in order to mount the chip capacitor on the carrier tape, first, a solder-plated land is formed on the carrier tape, followed by forming a solder on the land by printing using a mount device. Then, the chip capacitor is placed on the solder for reflow soldering. Thus, mounting the chip capacitor on the carrier tape increases the number of assembly steps, and thus the cost.
In view of foregoing problems, for example, Japanese Unexamined Patent Publication No. 183102/1993 (Tokukaihei 5-183102) (published date: Jul. 23, 1993) discloses a semiconductor device in which two semiconductor chips are stacked on a carrier tape.
As shown in
FIG. 13
, the semiconductor device of the foregoing publication includes a flexible film
201
having first inner leads
204
and second inner leads
205
which are formed on one surface of the substrate and project into an opening
201
a
of the substrate with different lengths. This semiconductor device is manufactured by the process as shown in FIG.
14
(
a
) through FIG.
14
(
d
).
That is, as shown in FIG.
14
(
a
) and FIG.
14
(
b
), a first semiconductor chip
211
and the first inner leads
204
are electrically bonded with each other by gang bond, and as shown in FIG.
14
(
c
) and FIG.
14
(
d
), a second semiconductor chip
212
and the second inner leads
205
are electrically bonded with each other by a single point bond on the opposite side of the first semiconductor chip
211
. The semiconductor device thus manufactured has a stacked structure of two semiconductor chips on a single plane.
In the semiconductor device having the foregoing structure, the stacked semiconductor chips can be adapted to have different functions, for example, by adopting the function of the liquid crystal driving segment and common drivers for one semiconductor chip and the function of the SRAM for the other semiconductor chip. This makes it possible to reduce the chip area compared with the case where the two functions are included in a single semiconductor chip.
However, in the semiconductor device of the foregoing publication, as show in FIG.
14
(
c
), the bonding between the second semiconductor device
212
and the second inner leads
205
are carried out on the side of the first semiconductor chip
211
which is bonded with the first inner leads
204
. Thus, considering a possible damage or other adverse effects on the first semiconductor chip
211
, the bonding has to be made by a single point bond. This increases the time required for bonding the second semiconductor chip
212
and the second inner leads
205
. As a result, manufacturing time of the semiconductor device is greatly increased.
Further, as shown in
FIG. 12
, the inner leads
124
and
125
bonded with the semiconductor chip
112
are usually bent to have a function of a dumper against an external force which acts on the semiconductor chip
112
, so as to prevent wire breakage between the inner leads
124
and
125
and the semiconductor chip
112
.
In contrast, in the semiconductor device of the foregoing publication, the first semiconductor chip
211
and the second semiconductor chip
212
are face to face and are connected to the first inner leads
204
and the second inner leads
205
of different lengths. Further, the first inner leads
204
and the second inner leads
205
are held nearly horizontally with respect to the wiring bearing surface of the flexible film
201
. That is, the inner leads cannot have the dumping function. Thus, when an external force acts on the semiconductor chip to pull it, wire breakage easily occurs between the semiconductor chips and the inner leads.
Thus, when the semiconductor device of the foregoing publication is applied to the liquid crystal module, while the size of the device can be reduced compared with the semiconductor device having two functions (segment driver and common driver) in a single semiconductor chip, reliability of the liquid crystal module suffers by the susceptibility of wire breakage between the semiconductor chips and the inner leads.
SUMMARY OF THE INVENTION
The present invention was made in view of the foregoing problems, and it is an object of the present invention to provide a semiconductor device which requires a notably less manufacturing time by bonding a semiconductor chip or an electrical component (such as a semiconductor chip) and inner leads in a shorter period of time, and which
Nixon & Vanderhye P.C.
Sharp Kabushiki Kaisha
Wojciechowicz Edward
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