Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – Insulating material
Reexamination Certificate
2002-03-29
2004-03-02
Flynn, Nathan J. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
Insulating material
C257S706000, C257S701000, C257S787000, C257S796000
Reexamination Certificate
active
06700194
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device, in particular, to a semiconductor device for power which withstands a high voltage.
2. Description of the Background Art
FIG. 29
shows a cross section view of the structure of the semiconductor device M
70
as an example of a conventional semiconductor device. As shown in
FIG. 29
, in the semiconductor device M
70
, for example, an insulating substrate
102
is mounted on a base plate
104
formed of oxygen-free copper and a semiconductor element
101
, which is a switching element, is mounted on this insulating substrate
102
. On the insulating substrate
102
, a predetermined conductor pattern is provided on one of the main surfaces of the insulating substrate and a semiconductor element, or the like, is provided on this conductor pattern. In addition, a conductor layer is provided on the other main surface so as to provide a structure that can be adhered to a conductor plate, or the like, by means of soldering, or the like.
A resin case
105
which is formed of, for example, PPS (polyphenylene sulphide) is provided so as to surround the peripheral parts of the base plate
104
.
The resin case
105
is provided with an electrode plate DE which is formed of an external connection electrode plate
108
, a connection conductor
106
and an internal connection electrode
107
so as to be partially buried. The internal connection electrode
107
is electrically connected to the semiconductor element
101
or to the conductor pattern of the insulating substrate
102
through an aluminum wire
109
of the diameter of 200 &mgr;m to 300 &mgr;m.
Then, the internal space defined by the base plate
104
and the resin case
105
is filled in with, for example, silicone gel
110
in order to secure the insulation and a lid
111
is provided over the opening of the resin case
105
in order to block the silicone gel
110
from the air outside.
In addition, part of the main surface of the external connection electrode plate
108
is exposed on the main surface of the resin case
105
and a through hole is created in such part for the connection with an external conductor (not shown) while a nut
112
is buried in the resin case
105
in the place which corresponds to this through hole. Accordingly, the external connection electrode plate
108
and the external conductor can be connected by using a bolt (not shown) so that the contact resistance can be made small by fastening the bolt.
In this manner, a configuration wherein the semiconductor element
101
is contained in the resin case
105
is adopted in the semiconductor device M
70
and, therefore, the manufacturing process becomes complicated, the dimensions of the external form become large and miniaturization or cost reduction are limited.
In addition,
FIG. 30
shows a cross section view of the configuration of the semiconductor device M
80
as an example of a conventional semiconductor device.
As shown in
FIG. 30
, in the semiconductor device M
80
, a semiconductor element
201
which is a switching element is mounted on a frame
213
which is formed of, for example, a copper alloy and the semiconductor element
201
is electrically connected to the lead
207
through an aluminum wire
209
.
The semiconductor element
201
, the lead
207
and the frame
213
are sealed in a mold resin
214
by using a transfer molding so as to be integrated. Then, a part of the lead
207
and a part of a lead
215
which extends from the frame
213
protrude to the outside from the mold resin
214
so as to be soldered to, for example, a printed circuit board which has through holes.
In this manner, though in the semiconductor device M
80
, the semiconductor element
201
is sealed in a resin by using transfer molding so that the number of parts is small and the cost can be held low, the heat emitted by the semiconductor element
201
at the time of the operation is radiated through the mold resin
214
of which the heat conductance is several Wm·K with a high heat resistance so as to have a problem radiating heat.
In addition, the lead
207
is thin and the cross section area of the lead
207
and the cross section area of the circuit pattern on the printed circuit board for allowing a heavy current to flow to which the lead
207
is connected cannot be sufficiently secured and, therefore, the loss due to the electrical resistance cannot be ignored and there is the problem that the lead is not suitable for a semiconductor device for a heavy current.
In addition,
FIG. 31
shows a cross section view of the configuration of the semiconductor device M
90
as an example of a conventional semiconductor device.
As shown in
FIG. 31
, in the semiconductor device M
90
, a semiconductor element
301
which is a switching element is mounted on an insulating substrate
302
and the semiconductor element
301
is electrically connected to a lead
315
through an aluminum wire
309
. Then, the insulating substrate
302
, the semiconductor element
301
and the lead
315
are sealed in a mold resin
314
by using transfer molding so as to be integrated.
A main surface of the insulating substrate
302
opposite to the main surface, on which the semiconductor element
301
is mounted, is exposed from the mold resin
314
and is soldered to a metal substrate
304
. In addition, a control circuit substrate
317
or a relay substrate
318
are also provided on the metal substrate
304
.
The control circuit substrate
317
is a substrate on which a control circuit, or the like, for controlling the operation of the semiconductor element
301
is provided and the relay substrate
318
is a substrate to which a relay point of the lead
315
is provided.
The leads
315
which extend from mold resin
314
are connected to the relay substrate
318
and a conductor layer
319
which is provided on the control circuit substrate
317
and the lead
315
which is connected to the relay substrate
318
is electrically connected to the external connection electrode plate
316
via the conductive layer
319
and the lead
315
connected to the control circuit substrate
317
is connected to a control terminal
320
via the conductive layer
319
.
In this manner, in the semiconductor device M
90
, the insulating substrate
302
, on which the semiconductor element
301
is mounted, contacts the metal substrate
304
and, therefore, the semiconductor device M
90
is superior to the semiconductor device M
80
concerning the radiation of heat. However, the control circuit substrate
317
and the relay substrate
318
are separately provided on the metal substrate
304
and, therefore, layout efficiency is poor and there is the problem that miniaturization is difficult.
In addition, the area of the loop circuit, which is formed starting from and reaching to the external connection electrode plate
316
via the relay substrate
318
, the lead
315
, one of the main electrodes of the semiconductor element
301
, the other main electrode, the relay substrate
318
and the lead
315
, becomes large so as to have a large inductance and this becomes a factor leading to the occurrence of a large surge voltage. Therefore, the change ratio of the current becomes large in the case that the semiconductor element
301
is operated in a switching manner and, therefore, an element which withstands a high voltage must be prepared and this becomes a factor leading to an increase in the cost.
As described above, in a conventional semiconductor device, it is difficult to satisfy both the requirements concerning the radiation of heat and concerning miniaturization.
SUMMARY OF THE INVENTION
According to the first aspect of the present invention, a semiconductor device comprises a radiation substrate, semiconductor elements provided on the radiation substrate, a plurality of main electrode plates of which one end is electrically connected to a main electrode of the semiconductor elements, respectively and a resin package for sealing the radiation substrate, the semiconductor elements and the p
Chuma Hideaki
Nakajima Dai
Flynn Nathan J.
Greene Pershelle
Mitsubishi Denki & Kabushiki Kaisha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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