Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – With contact or lead
Reexamination Certificate
2002-09-12
2004-03-23
Clark, Sheila V. (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
With contact or lead
C257S666000, C257S724000, C438S110000
Reexamination Certificate
active
06710439
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power semiconductor module, and more particularly, to a power semiconductor module in which a main circuit terminal lead frame part and a control circuit lead frame part are bent toward a main circuit lead frame part.
2. Description of the Related Art
Advancement in the power electronics industry, e.g., inverters and servo drivers, triggers a need for a light and compact power system that is manufactured at a low cost and operates more efficiently. To realize such a power system, electronic components are integrated into one package, i.e., a power semiconductor module, and a large number of power devices and control integrated circuits (IC), which control the power devices, are integrated into one power semiconductor module that is capable of controlling and protecting power devices. This power semiconductor module is called an ‘intelligent power module’.
FIGS. 1 through 3
are views of conventional power semiconductor modules.
FIG. 1
is a view of a semiconductor package disclosed in U.S. Pat. No. 6,002,166. Referring to
FIG. 1
, all components (some not shown) such as a semiconductor device and a control circuit device are combined with one another by solder (not shown), and a semiconductor chip
1
attached to a lead frame (not shown) is electrically connected with a terminal
5
by a bonding wire (not shown). The size of the semiconductor package of
FIG. 1
is determined according to the sizes of all components attached to the lead frame. Thus, an increase in the number of components required results in an increase in the size of the semiconductor package. As the size of the semiconductor package increases, more components, such as a substrate and a mold compound, are required in fabricating the semiconductor package, thus increasing manufacturing costs therefor. Also, in the semiconductor package, the distance between a base substrate
3
, which contacts a heat sink (not shown), and a terminal
5
extended to the exterior of a mold compound
7
, which molds the semiconductor package, is approximately 4-5 mm. In other words, the isolation height h, which is the distance between the terminal
5
connected to the exterior circuit and the heat sink, is about 4-5 mm. Therefore, the isolation height of the semiconductor package is lower than the UL (underwriters laboratory) standard, i.e., 12.7 mm. If the isolation height is below the UL, the electrical insulation of a semiconductor package deteriorates.
FIG. 2
is a view of a semiconductor package disclosed in U.S. Pat. No. 5,521,437. Referring to
FIG. 2
, all components are attached to an insulated metal substrate
16
and are electrically connected to one another by a bonding wire
18
. Thus, the size of the semiconductor package is determined by the size of the insulated metal substrate
16
to which all components are attached. That is, an increase in the number of the components required results in an increase in the size of the semiconductor package. Also, as the size of the semiconductor package increases, a great number of components, such as an insulated metal substrate and a mold compound, are required in fabricating the semiconductor package, thus raising manufacturing costs therefor. In
FIG. 2
, reference numerals
11
,
13
,
15
,
17
and
19
denote a case, a control circuit terminal, a main circuit terminal, a main circuit part, and a control circuit unit, respectively.
FIG. 3
is a view of a semiconductor package disclosed in U.S. Pat. No. 5,471,089. Referring to
FIG. 3
, a main circuit part
35
having a power semiconductor device and a control circuit part
33
including a control circuit device are formed on different substrates. The main circuit part
35
and the control circuit part
33
are installed at the top and bottom of the semiconductor package, respectively. Also, they are connected to each other by a metal connection
37
. Portions of the main circuit part
35
and the control circuit part
33
that contact the metal connection
37
are soldered by a solder
32
. In conclusion, in the semiconductor package shown in
FIG. 3
, the main circuit part
35
and the control circuit part
33
are formed on different substrates at the top and bottom of the semiconductor package. Also, the metal connection
37
and the solder
32
are indispensable in connecting the main circuit part
35
with the control circuit part
33
. Accordingly, it is very difficult to realize such a semiconductor package. Here, reference numerals
31
and
39
denote a terminal and a case, respectively.
BRIEF SUMMARY OF THE INVENTION
To solve the above problem, it is a first objective of the present invention to provide a light and compact power semiconductor module that is simple to manufacture at a lower cost.
It is a second objective of the present invention to provide a method of fabricating such a power semiconductor module.
Accordingly, to achieve an aspect of the first objective, there is provided a three-dimensional power semiconductor module according to an embodiment of the present invention. The power semiconductor module includes a main circuit part mounted on an isolation substrate and including a power semiconductor device; a control circuit part positioned along a plane, forming a predetermined angle to the main circuit part, the control circuit part attached to a control circuit device; a control circuit terminal connected to the control circuit part; a main circuit terminal positioned along another plane, forming a predetermined angle to the main circuit part; a bonding wire for electrically connecting the control circuit terminal, the control circuit device, the power semiconductor device, and the main circuit terminal; and a mold compound for completely molding the main circuit part and the control circuit part.
Preferably, the main control part is attached to the isolation substrate by an adhesive, and the control circuit part is positioned along a plane perpendicular to the main circuit part.
Preferably, the control circuit terminal is positioned along the same plane as the control circuit part.
Preferably, the main circuit terminal is placed along a different plane, making it symmetrical with the control circuit part with reference to the main circuit part.
Preferably, the main circuit part and the control circuit part are completely molded by the mold compound such that a trench is formed in a space between the control circuit terminal and the main circuit terminal.
Preferably, an impulse buffer agent is formed at the ends of the bonding wire.
To achieve another aspect of the first objective, there is provided a three dimensional power semiconductor module. The power semiconductor module includes a main circuit part mounted on an isolation substrate and including a power semiconductor device thereon; a control circuit part placed along a plane perpendicular to the main circuit part such that a control circuit device turns toward the power semiconductor device included in the main circuit part, the control circuit part including the control circuit device; a control circuit terminal placed along the same plane as the control circuit part, the control circuit terminal connected to the control circuit part; a main circuit terminal positioned along a different plane perpendicular to the main circuit part, facing the control circuit part and the control circuit terminal; a bonding wire for electrically connecting the control circuit terminal, the control circuit terminal, the power semiconductor device, and the main circuit terminal; and a mold compound for molding the main circuit part, the control circuit part, a portion of the main circuit terminal, and the entire isolation substrate, excluding its lower part, thereby conforming the module into a hexahedral shape.
Preferably, the main circuit part is bonded to the isolation substrate by an adhesive.
Preferably, an impulse buffer agent is formed at the ends of the bonding wire.
To achieve still another aspect of the first objective, there is provided a three dimensio
Jeon O-seob
Jeun Gi-Young
Lee Keun-hyuk
Clark Sheila V.
Fairchild Korea Semiconductor Ltd.
Townsend and Townsend / and Crew LLP
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