Active solid-state devices (e.g. – transistors – solid-state diode – Combined with electrical contact or lead
Reexamination Certificate
2001-08-01
2004-05-04
Flynn, Nathan J. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Combined with electrical contact or lead
C257S712000, C257S687000, C257S787000
Reexamination Certificate
active
06731001
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of Japanese Patent Applications No. 2000-243278 filed on Aug. 10, 2000, No. 2000-243279 filed on Aug. 10, 2000, No. 2000-243280 filed on Aug. 10, 2000, and No. 2000-243281 filed on Aug. 10, 2000, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a semiconductor device having an electronic part that is mounted on and electrically connected to a substrate through a bonding wire and sealed together with the bonding wire.
2. Description of the Related Art
FIGS. 1 and 2
show a semiconductor device
200
. In the semiconductor device
200
, referring to
FIG. 1
, several ceramic substrates
204
are disposed approximately perpendicularly to a motherboard
202
on which various electronic parts
201
are mounted. Referring to
FIG. 2
, electronic parts
203
are mounted on a surface of each ceramic substrate
204
, and the other surface thereof is bonded to a radiation member
205
by silicone system conditioner
210
. An end of a connection terminal (clip terminal)
206
is bonded to an edge portion of each ceramic substrate
204
at a side of the motherboard
202
. The connection terminal
206
is positioned via an array board
207
, and the other end of the connection terminal
206
is electrically connected to the motherboard
201
.
These parts
201
to
207
are housed in a case
208
. The electronic parts
203
mounted on the ceramic substrates
204
, are surrounded by a protruding portion
208
a
of the case
208
to be protected from external environment and to improve radiation properties thereof, and are sealed with resin
209
or the like.
In the semiconductor device
200
having the above-described structure, as shown in
FIGS. 1 and 2
, in order to improve the efficiency in manufacturing steps, the several ceramic substrates
204
are disposed on the identical surface of the support member (radiation member)
205
, and all the electronic parts
203
are sealed with the resin
209
together. In general, silicone rubber or the like having high viscosity is used as the resin
209
because it is easy to handle.
However, in a case where the electronic parts
203
are electrically connected to the ceramic substrates
204
by fine bonding wires, there is a possibility that the bonding wires are broken or strained when the resin is poured. The strained wires may be broken due to the resin
209
that strains when the semiconductor device
200
undergoes thermal shock cycles. Especially, when each diameter of the wires is smaller than 150 &mgr;m, this problem becomes prominent. In view of this point, silicone gel having low viscosity is preferred to seal the electronic parts
203
.
However, when all the electronic parts
203
are sealed by silicone gel together, the following problems arise. First, because gal having low viscosity is disposed in a large volume (area), the gel may oscillate to break the bonding wires when the semiconductor device
200
oscillates. Further, when gel is injected, bubbles are liable to be produced in the injected gel at step portions or the like between the ceramic substrates
204
and the radiation member
205
. If bubbles exist around the fine bonding wires, the bubbles strain the gel during the thermal shock cycles of the semiconductor device
200
, and as a result, the strained gel can strain the bonding wires.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above problems. An object of the present invention is to provide a semiconductor device capable of restricting strain and breakage of a bonding wire wire-bonded to an electronic part sealed therein.
According to a first aspect of the present invention, a plurality of substrates are attached to a support member, and an electronic part is mounted on one of the substrates and electrically connected to the one through a bonding wire. An enclosing member covers the electronic part and the bonding wire, and a sealing material fills the enclosing member for sealing the electronic part and the bonding wire. Preferably, the enclosing member is composed of a plurality of enclosing members each of which is attached to a corresponding one of the plurality of substrates.
Because the electronic part and the bonding wire is covered with the enclosing member on every substrate, a volume of the sealing material filling the enclosing member is reduced, resulting in reduced amplitude of the sealing material. Further, bubbles are less liable to be produced in the sealing material. As a result, the bonding wire is restrained from being strained or broken by bubbles and the like.
According to a second aspect of the present invention, an electronic part is mounted on a substrate, and is electrically connected to the substrate through a bonding wire. An enclosing member covers the electronic part and the bonding wire, and a sealing material fills the enclosing member for sealing the electronic part and the bonding wire. The enclosing member has a first opening portion for injecting the sealing material into the enclosing member and a second opening portion for releasing gas from the enclosing member when the sealing material is injected. Preferably, the second opening portion has a width equal to or larger than that of the first opening portion. In this case, because gas can be released from the sealing material easily, bubbles produced in the sealing material can be reduced.
According to a third aspect of the present invention, an electronic part is disposed on a substrate, and a sealing member covering and sealing an electronic part and a bonding wire has a height equal to or smaller than 5 mm in a normal direction of the substrate, a shape that is contained in a rectangle having a long side of 60 mm and a short side of 20 mm, and a penetration in a range of 40 to 170 mm/10 (Refer to Japanese Industrial Standard (JIS), K 2220). The height of the sealing member is preferably equal to or smaller than 3 mm, and more preferably equal to or smaller than 2.5 mm. As a result, the oscillation of the sealing member can be suppressed, thereby preventing strain and breakage of the bonding wire.
According to a fourth aspect of the present invention, a method for manufacturing a semiconductor device comprises disposing an electronic part on a substrate; soldering a solder connecting member to the substrate; washing the substrate in a first solvent for removing flux from the substrate while keeping a concentration of the flux in the first solvent being 0.4 wt % or less, the flux being used when the solder connecting member is soldered; washing the substrate in a second solvent for removing the first solvent from the substrate, while keeping a concentration of the first solvent dissolved in the second solvent being 0.8 wt % or less; and electrically connecting the electronic part to the substrate by wire bonding using a bonding wire. In this method, because washing residues can be removed effectively, the connecting property of the bonding wire can be improved.
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Wolf et al., Silicon Processing for the VLS
Imai Hirokazu
Kanamori Atsushi
Kinouchi Kan
Maeda Yukihiro
Nagasaka Takashi
Andujar Leonardo
Denso Corporation
Flynn Nathan J.
Posz & Bethards, PLC
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