Active solid-state devices (e.g. – transistors – solid-state diode – Field effect device – Having insulated electrode
Reexamination Certificate
2002-08-02
2004-06-22
Le, Dung (Department: 2818)
Active solid-state devices (e.g., transistors, solid-state diode
Field effect device
Having insulated electrode
C257S380000, C257S541000, C438S330000, C438S382000
Reexamination Certificate
active
06753578
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a resin-sealed semiconductor device.
2. Description of the Related Art
As well known, a semiconductor power device such as an intelligent power module for use in a power source incorporated in an inverter device for household electrical or industrial appliances, comprises primary components such as power chips and control ICs provided on the upper surface of a substrate which is supported in an enclosure, and generally sealed with a curing resin material for protection against an external environment.
FIG. 10
is a plan view schematically showing a conventional resin-sealed semiconductor power device before being sealed with a resin material. The semiconductor power device
80
has an IGBT
83
as a power chip, a FWDi (Free Wheel Diode)
84
, and a control IC
85
provided on an insulating substrate
82
which is supported in an enclosure
81
. In addition, provided on the upper main surface of the insulating substrate
82
is a milliohm resistor
86
of a plate-like shape. The enclosure
81
is equipped with a set of external connection terminals
87
which is insert formed. Also, bonding wires are provided on the upper main surface of the insulating substrate
82
, as well as circuit patterns, for electrical connection between the components but not shown in
FIG. 10
for simplicity of the description.
FIG. 11
is a longitudinal cross sectional view of the milliohm resistor
86
taken along the line C—C of FIG.
10
. The milliohm resistor
86
is arranged of generally a raised form of its plate-like material which is anchored at both ends (denoted by
86
b
) to the insulating substrate
82
. Accordingly, a space
90
is provided as defined between the milliohm resistor
86
and the upper main surface
82
a
of the insulating substrate
82
. A raised portion
86
a
of the milliohm resistor
86
extends in parallel with the insulating substrate
82
.
The components on the insulating substrate
82
are sealed with a curing resin
92
for protection against the external environment as shown in FIG.
12
. However, as the milliohm resistor
86
and the enclosure
81
of the semiconductor power device
80
are located adjacent to each other in the resin sealing step, the space
90
defined between the milliohm resistor
86
and the insulating substrate
82
may hardly be filled with the resin
92
but bubbles of air. When the air escapes from the space
90
during the curing of the resin, it may produce a void(s)
92
a
at the surface in the resin
92
. Otherwise, the air trapped in the space
90
may decline the thermal conductivity of the milliohm resistor
86
and thus prevent the milliohm resistor
86
from releasing a redundancy of heat.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a resin-sealed semiconductor device which allows unwanted air to be bled out steadily and readily from the space defined between the resistor of a plate-like shape and the insulating substrate in the resin sealing step.
A resin-sealed semiconductor device in an aspect of the present invention includes a resistor of a plate-like form placed and anchored at both ends onto the upper main surface of a substrate, providing a space between the resistor and the substrate. The primary components including said resistor on the substrate are sealed with a curing resin material. In this resin-sealed semiconductor device, the resistor includes a portion which is opposite to the substrate and defines the space with the substrate, and an aperture is formed in said portion for communication between the space and the upper side of the resistor.
Accordingly, an air can be prevented from entrapping in the space during the resin packaging step. As a result, the generation of voids in the resin when cured can be prevented. Also, as its aperture and space are steadily filled with the resin, the resistor remains high in the thermal conductivity and can thus be inhibited from generating overheat.
Said aperture is located at substantially the center of said portion of the resistor. This allows unwanted air to be effectively bled from the space.
A roughness of a surface facing the substrate (that is, a lower surface) in said portion of the resistor is set to 2S or lower. This also allows unwanted air to be effectively bled from the space with much ease.
REFERENCES:
patent: 6037844 (2000-03-01), Makino et al.
patent: 56-167336 (1981-12-01), None
Kanenari Toshiaki
Nakajima Toshihiro
Le Dung
Mitsubishi Denki & Kabushiki Kaisha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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