Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – With semiconductor element forming part
Reexamination Certificate
2000-11-17
2002-11-26
Elms, Richard (Department: 2824)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
With semiconductor element forming part
C257S099000, C438S106000, C438S116000
Reexamination Certificate
active
06486543
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a resin-packaged semiconductor device surface-mountable onto an object surface such as a circuit substrate, and more specifically, to a semiconductor device suitably used as a light emitter or a light receiver of an optical sensor.
BACKGROUND ART
Referring to the attached drawings, FIG.
29
and
FIG. 30
show a typical conventional resin-packaged semiconductor device. This semiconductor device Y is a light emitting diode (LED) of a so-called frame type, made from a lead frame obtained by punching a metal plate for example.
Specifically, the light emitting diode Y comprises a pair of leads
1
,
2
respectively including inner terminals
10
,
20
and outer terminals
11
,
21
, a semiconductor chip (light emitting element)
3
mounted to the inner terminal
10
of the lead
1
, a wire W for connecting an upper surface
30
of the light emitting element
3
to the inner terminal
20
of the other lead
20
, and a resin package
4
for sealing the inner terminals
10
,
20
of the leads
1
,
2
, the light emitting element
3
and the wire W. The resin package
4
is formed to have a convex lens
46
right above the light emitting element
3
. Each of the outer terminals
11
,
21
is bent like a crank so that the tip portion
11
a
,
21
b
is flush with a bottom surface
45
of the resin package
4
.
With the above arrangement, the light emitting diode Y is surface-mounted on an object surface
5
such as a circuit substrate, and used as a light source for various purposes such as a light source of an optical sensor. When the light emitting diode Y is surface-mounted to the object surface
5
, so called solder re-flow method is generally used. When the light emitting diode Y is mounted by means of the solder re-flow method, first, cream solder is applied to the tip portions
11
a
,
21
a
of the outer terminals
11
,
21
for example. Then, the light emitting diode Y is lowered, with its tip portions
11
a
,
21
a
being aligned with their corresponding terminal pads
50
on the object surface
5
, and then is placed in a re-flow furnace. In the re-flow furnace, the solder paste is re-melted under a temperature of about 200° C. When the melted solder sets again, the light emitting diode Y is fixed on the object surface
5
, completing the mounting process.
However, according to the light emitting diode Y, only the tip portions
11
a
,
21
a
of the outer terminals
11
,
21
serve as the mounting portions to be fixed onto the object surface
5
. This unitary determines the direction in which the light emitting diode Y can be faced. Specifically, if the upper surface
30
of the light emitting element
3
serves as the light emitting surface, the light emitting diode Y can only be mounted so as to emit light upward with respect to the object surface
5
, or in other words, the light emitting diode Y cannot be mounted for emitting in parallel to the object surface
5
. Therefore, in order to emit in parallel to the object surface
5
, another light emitting diode must be prepared in which the emitting surface is vertical with respect to the bottom surface
45
(mounting surface) of the resin package
4
. As exemplified as above, according to the conventional light emitting diode, there is an inconvenience in that different kinds of the light emitting diode must be prepared depending on the direction in which the light is to be emitted. The same inconvenience can also pose a problem in such semiconductor devices as a photodiode and a phototransistor in which a light receiving element is used as the semiconductor device chip
3
.
DISCLOSURE OF THE INVENTION
It is therefore an object of the present invention to provide a semiconductor device capable of solving the above described problem.
According to a first aspect of the present invention, there is provided a semiconductor device comprising a semiconductor chip, a first lead connected to an electrode of the semiconductor chip, a second lead connected to another electrode of the semiconductor chip, and a resin package sealing the semiconductor chip, an inner terminal of the first lead, and an inner terminal of the second lead, wherein the resin package includes a first to a fourth side surfaces, an upper surface and a bottom surface, and each of the first and the second leads includes at least one outer terminal located near a corner portion of the resin package and extending along a same side surface of the first to the fourth side surfaces and the bottom surface of the resin package.
According to the above arrangement, an anode/cathode pair is formed at least in one of the side surfaces and in the bottom surface of the resin package. Therefore, when mounting the semiconductor device onto an object surface such as a circuit substrate, either of said one side surface and the bottom surface can be selected as a mounting surface.
According to an embodiment of the present invention, the outer terminal of the first lead includes a drop portion extending from the corresponding inner terminal along the first side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the third side surface of the resin package. The outer terminal of the second lead includes a drop portion extending from the corresponding inner terminal along the first side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the fourth side surface opposite to the third side surface of the resin package.
According to another embodiment of the present invention, the outer terminal of the first lead includes a drop portion extending from the corresponding inner terminal along the first side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the third side surface of the resin package, wherein the outer terminal of the second lead includes, a drop portion extending from the corresponding inner terminal along the second side surface opposite to the first side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the third side surface of the resin package.
According to still another embodiment of the resent invention, the outer terminal of the first lead includes a drop portion extending from the corresponding inner terminal along the third side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the third side surface of the resin package, wherein the outer terminal of the second lead includes a drop portion extending from the corresponding inner terminal along the third side surface of the resin package, a bottom portion extending from the drop portion along the bottom surface of the resin package, and a riser portion extending from the bottom portion along the second side surface opposite to the first side surface of the resin package.
According to still another embodiment of the present invention, the outer terminal of the first lead includes two branch portions, and one of the branch portions is bent to extend along the first side surface and the bottom surface of the resin package, whereas the outer terminal of the second lead includes two branch portions, and one of the branch portions is bent to extend along the first side surface and the bottom surface of the resin package. In this case, the other branch portion of the outer terminal of the first lead extends along the first side surface beyond the third side surface of the resin package whereas the other branch portion of the outer terminal of the second lead extends along the first side surface beyond the fourth
Sano Masashi
Suzuki Nobuaki
Suzuki Shinishi
Bednarek Michael D.
Elms Richard
Rohm & Co., Ltd.
Shaw Pittman LLP
Smith Brad
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