Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – With reflector – opaque mask – or optical element integral...
Reexamination Certificate
2000-11-27
2003-08-05
Fahmy Jr., Wael (Department: 2814)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
With reflector, opaque mask, or optical element integral...
C257S095000, C257S692000, C257S790000
Reexamination Certificate
active
06603148
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a resin-packaged semiconductor device. More specifically, the present invention relates to a semiconductor device suitably used as surface-mounted on a substrate.
BACKGROUND ART
FIG.
18
and
FIG. 19
show a prior art semiconductor device. The illustrated semiconductor device B is constituted as a light emitting device, and comprises a resin package
90
, a semiconductor chip
93
, a wire W, a first lead
91
, and a second lead
92
. The first and the second leads
91
,
92
respectively include horizontal inner terminals
91
a,
91
b
enclosed within the resin package
90
, and outer terminals
91
b,
92
b
exposed outside of the resin package
90
. The outer terminals
91
b,
92
b
have respective bottom surface portions
94
a,
94
b
flush with a bottom surface
90
b
of the resin package
90
. The semiconductor chip
93
is a light emitting element for example, and is bonded to the internal terminal
91
a
and sealed into the resin package
90
. The wire W has a first end bonded to an electrode on an upper surface of the semiconductor chip
93
and a second end bonded to the inner terminal
92
a,
and is sealed into the resin package
90
. The resin package
90
is made, for example, of a transparent epoxy resin not mixed with filler, and has an upper surface
90
a
formed with a lens portion
95
serving as a convex lens.
The semiconductor device B described above has following problems.
First, the wire W can fail if the semiconductor device B is surface-mounted on a substrate by means of a solder re-flow method. More specifically, as shown in
FIG. 19
, when the semiconductor device B is surface-mounted on a substrate
96
, solder paste H is applied to electrode pads
97
a,
97
b
on the substrate
96
. Next, semiconductor device B is placed on the substrate
96
so that the bottom surface portions
94
a,
94
b
of the outer terminals
91
b,
92
b
are located on the corresponding electrode pads
97
a,
97
b.
The substrate
96
and the semiconductor device B in this state is brought in a heating furnace and heated. The temperature in the heating furnace is about 240° C. for example. Thus, the applied solder paste H is re-melted. Thereafter, the substrate
96
and the semiconductor device B are taken out of the heating furnace and allowed to cool, so that the solder paste H sets to fix the semiconductor device B onto the substrate
96
.
In the series of operations as described above, at the cooling step which follows the re-melting step, the solder paste H becomes solid at a temperature of 183° C. for example, fixing the first and the second leads
91
,
92
onto the electrode pads
97
a,
97
b.
However, at this particular point (at the temperature of 183° C.), the resin package
90
is still soft, staying in a thermally expanded state, being in a course of thermal shrinkage with ongoing further decrease in the temperature. This is because the epoxy resin not mixed with filler has a glass transformation temperature of about 120° C., which is lower than the setting temperature of the solder paste H.
If the resin package
90
shrinks after the first and the second leads
91
,
92
have been fixed onto the electrode pads
97
a,
97
b,
a shrinking force of the resin package
90
is exerted to the semiconductor chip
93
and the wire W which are connected to the first and the second leads
91
,
92
respectively. This can cause the wire W to fail at a location of the bonding.
Secondly, according to the prior art, when light from the semiconductor chip
93
is condensed by the lens portion
95
, it is desirable that there is a large space between the lens portion
95
and the semiconductor chip
93
in order to increase light condensing effect. This is because the light emitted from the semiconductor chip
93
advances in a certain diffusing angle. If a longer distance is provided between the semiconductor chip
93
and the lens portion
95
, the light reaching the lens portion
95
becomes closer to a beam which is parallel to an optical axis of the lens portion
95
.
However, according to the prior art, if the distance between the semiconductor chip
93
and the lens portion
95
is increased by increasing a thickness of the resin in between, then an overall size of the semiconductor device B has to be increased. On the other hand, as shown in
FIG. 20
, if a height of the inner terminals
91
a,
92
a
in the resin package
90
is decreased, a thickness t of the resin beneath these inner terminals
91
a,
92
a
has to be decreased in a wide range. This sacrifices strength of the resin package
90
, making the resin package
90
susceptible to a crack.
DISCLOSURE OF THE INVENTION
It is therefore an object of the present invention to provide a semiconductor device capable of solving or reducing the above described problem in the prior art.
A semiconductor device provided by a the present invention comprises:
a resin package including an upper surface, a bottom surface opposed thereto thickness wise, a first side surface and a second side surface opposed to the first surface widthwise;
a semiconductor chip sealed in the resin package;
a wire sealed in the resin package and including a first end bonded to the semiconductor chip;
a first lead including a first inner terminal entering from the first side surface into the resin package and a first outer terminal connecting to the first inner terminal and exposed to outside of the resin package, the semiconductor chip being bonded to the first inner terminal; and
a second lead including a second inner terminal entering from the second side surface into the resin package and a second outer terminal connecting to the second inner terminal and exposed to outside of the resin package, a second end portion of the wire being bonded to the second inner terminal.
According to this semiconductor device, at least one of the first and the second inner terminals is bent in a direction of the thickness of the resin package.
Preferably, the semiconductor chip provides a light emitting element or a light receiving element, and the resin package is capable of transmitting the light.
Preferably, the resin package is made of an epoxy resin.
Preferably, the upper surface of the resin package is provided with a lens portion for condensing light.
Preferably, the first inner terminal is bent, whereby displacing a bonding portion of the semiconductor chip closer to the bottom surface of the resin package than is a location where the first inner terminal enters the resin package in the first side surface.
Preferably, the first inner terminal is provided with a slanted surface facing each of the semiconductor chip and the lens portion and being capable of reflecting light received.
Preferably, the second inner terminal is bent, whereby providing the second inner terminal with a slanted surface facing each of the semiconductor chip and the lens portion and being capable of reflecting light received.
Preferably, the first inner terminal is provided with a recessed surface surrounding the semiconductor chip, facing the upper surface of the resin package and capable of reflecting light received.
Preferably, the recess provided by the recessed surface is filled with a covering material softer than the resin package and capable of transmitting light. Further, the semiconductor chip is covered by the covering material.
Preferably, each of the first and the second inner terminals is bent, whereby displacing the bonding portion of the semiconductor chip closer to the bottom surface of the resin package than is a location where the first inner terminal enters the resin package in the first side surface, and displacing the bonding portion of the second end of the wire closer to the bottom surface of the resin package than is a location where the second inner terminal enters the resin package in the second side surface.
Preferably, each of the first and the second inner terminals has a crank-like shape.
Preferably, each of the first and the second inner terminals is bent, whereby displacing the bonding portion of the
Sano Masashi
Suzuki Nobuaki
Suzuki Shin'ichi
Bednarek Michael D.
Fahmy Jr. Wael
Nguyen Dilinh
Rohm & Co., Ltd.
Shaw Pittman LLP
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