Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package
Reexamination Certificate
2002-08-07
2004-03-09
Vigushin, John B. (Department: 2827)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
C257S700000
Reexamination Certificate
active
06703699
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
A related patent application is a commonly assigned Japanese Patent Application No. 2002-36457 filed on Feb. 14, 2002, which is incorporated by reference into the present patent application.
BACKGROUND OF THE INVENTION
1) Technical Field of the Invention
The present invention relates to a power semiconductor device for controlling a substantial amount of current used for electrical systems such as a motor and a heater.
2) Description of Related Arts
Recent industrial systems incorporated in an electric car and an elevator, in particular, have been improved in smooth motion and comfort for ride. This improvement comes significantly from contribution of power semiconductor devices that control the power (current) of such systems. In the power semiconductor devices, a substantial amount of heat is generated, which should efficiently be radiated outside of the power semiconductor device, for example, by using a radiating fin.
Referring to
FIGS. 8 through 10
, a conventional power semiconductor device will be described hereinafter. A power semiconductor device
101
shown in
FIG. 8
includes, in general, a housing
110
made of insulating material such as resin and a base plate
130
made of metal of a good thermal conductivity such as copper. The housing
110
has a bottom surface fixed on the base plate
130
by means of metal screws or adhesive (not shown). As shown in
FIG. 9
, the power semiconductor device
101
also includes a plurality of main terminals
111
extending from an upper surface to an inside portion of the housing
110
. The device
101
also includes an insulating substrate
115
with patterned metal layers
114
a
,
114
b
formed on both sides thereof, and a power semiconductor chip
120
mounted on the upper metal layer
114
a
by means of solder
116
. The power semiconductor chip
120
is supplied with electric power from the main terminals
111
through a plurality of metal wires
123
of metal such as aluminum. The lower metal layer
114
b
of the insulating substrate
115
is bonded on the base plate
130
through a solder
117
.
In the power semiconductor device
101
, for protection of the semiconductor chip
120
, silicone gel
124
(the hatching thereof not shown for clarity) is filled over the semiconductor chip
120
and the insulating substrate
115
. The silicone gel
124
is then sealed by epoxy resin
125
deposited thereon. Lastly, a cover
126
is formed on the epoxy resin
125
.
When the power semiconductor device
101
so constructed is assembled within a peripheral device, a plurality of bus bars
140
, each of which is an external conducting plate (also referred to as “conducting member”), are arranged on and connected with the main terminals by means of metal screws
145
, as shown in FIG.
9
. Also, in the power semiconductor device
101
, in order to efficiently radiate undesirable heat generated by the semiconductor chip
120
outside of the power semiconductor device
101
, the base plate
130
is required to closely contact with a radiating fin
150
by means of a plurality of metal screws
147
, as illustrated by imaginary lines of FIG.
9
. Therefore, according to the power semiconductor device
101
, the base plate
130
needs four through-holes
148
formed at each corner thereof for receiving metal screws
147
so as to closely contact with the radiating fin
150
.
However, when the metal screws
147
are used to secure the base plate
130
on the radiating fin
150
, the housing
110
can not be extended beyond the space over the through-holes
148
of the base plate
130
. Thus, unavailable dead spaces are defined over the through-holes
148
, thereby preventing the power semiconductor device
101
from downsizing. As clearly illustrated in
FIG. 8
, in the actual assembly of the power semiconductor device
101
to the peripheral device, four screws
145
are required to connect two pairs of bus bars
140
with the corresponding main terminals
111
. And as above, another four screws
147
are essential to closely contact the base plate
130
with the radiating fin
150
. It is almost impossible to reduce the number of parts (screws) and tasks required for assembly.
SUMMARY OF THE INVENTION
The present invention has an object to provide a more compact power semiconductor device, in which the base plate and the radiating fin can be secured without defining any dead space.
Also, the present invention has another object to provide the power semiconductor device that can be assembled with reduced parts and tasks, in which close contact between the base plate and the radiating fin can be achieved simultaneously with connection between the bus bars and the main terminals.
Further, the present invention has another object to provide the power semiconductor device, which eliminates the base plate.
In particular, the present invention is to provide a semiconductor device, which includes a housing having a top and bottom surfaces, and an insulating substrate with metal layers formed on both sides thereof. The insulating substrate is surrounded within the housing. A semiconductor chip is mounted on one of the metal layer of the insulating substrate. Also, a terminal connector extends along the top surface of the housing and is bent towards the bottom surface thereof for supplying the semiconductor chip with power. In the semiconductor device, the housing has a housing through-hole extending from the top surface to the bottom surface through the housing, and also the terminal connector has a terminal through-hole which are aligned with and formed coaxially with the housing through-hole.
Therefore, a fastening member (screw) extending through the housing through-hole and the terminal through-hole can be used to fasten the semiconductor device with a metal radiator, and at the same time, to realize an electrical connection between a conducting member and a terminal connector. Thus, total time required for assembly with peripheral devices and for connection between the conducting member and the terminal connector can substantially be reduced. Also, the undesirable dead spaces of the prior art are eliminated and number of parts is reduced so that the power semiconductor device of the present invention is more compact, simpler in structure, and less expensive to manufacture than the conventional power semiconductor device.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the sprit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 10-32308 (1998-02-01), None
Mitsubishi Denki & Kabushiki Kaisha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Thai Luan
Vigushin John B.
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