Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – With heat sink means
Reexamination Certificate
1999-10-06
2003-04-29
Paladini, Albert W. (Department: 2827)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
With heat sink means
C257S680000, C257S690000, C257S707000, C257S713000, C257S724000, C361S707000, C361S711000, C361S718000
Reexamination Certificate
active
06555900
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a package for mounting a semiconductor chip therein and also relates to semiconductor device and method for fabricating the device using the package.
First, conventional package and semiconductor device will be described with reference to FIGS.
7
(
a
) and
7
(
b
).
FIGS.
7
(
a
) and
7
(
b
) illustrate conventional package and semiconductor device formed by mounting a semiconductor chip within the package. Specifically, FIG.
7
(
a
) illustrates a planar layout of the assembly yet to be encapsulated, while FIG.
7
(
b
) illustrates a cross-sectional structure of the assembly taken along the line VIIb—VIIb in FIG.
7
(
a
). As shown in FIGS.
7
(
a
) and
7
(
b
), an outer rail
102
made of an insulator is bonded to a radiating plate
101
made of copper. Input lead
103
A and output lead
103
B pass through the outer rail
102
and are insulated from the radiating plate
101
.
As can be seen, the conventional package is made up of the radiating plate
101
, outer rail
102
and input and output leads
103
A and
103
B.
As shown in FIG.
7
(
b
), semiconductor chips
104
, in which semiconductor components are formed as power amplifiers, are bonded to the radiating plate
101
of the package with a foil member
105
, which may be an alloy containing tin, inside the outer rail
102
.
Circuit boards
106
are also bonded to the radiating plate
101
with the foil member
105
inside the outer rail
102
. As shown in FIG.
7
(
a
), some of the circuit boards
106
are located between the semiconductor chips
104
and the input lead
103
A, while the other between the semiconductor chips
104
and the output lead
103
B. Each of these circuit boards
106
includes a matching circuit, which is formed on an insulating substrate to match the input impedance of the semiconductor components with the output one. The semiconductor chips
104
, circuit boards
106
and input and output leads
103
A and
103
B are connected together via wires
107
.
In manufacturing the semiconductor device, the semiconductor device assembled as shown in FIGS.
7
(
a
) and
7
(
b
) is heated within a reflow furnace, thereby melting the foil member
105
. Thereafter, the assembly is cooled down to room temperature, thereby bonding the radiating plate
101
to the semiconductor chips
104
and to the circuit boards
106
.
The conventional semiconductor device using such a package has the following drawbacks. Specifically, when the foil member
105
of an AuSn alloy is heated and melted by the reflow treatment, the melted foil member
105
expands on the radiating plate
101
. As a result, the semiconductor chips
104
and the circuit boards
106
are swept by the melted foil member
105
to be displaced from their desired positions.
SUMMARY OF THE INVENTION
An object of the present invention is preventing semiconductor chips and so on from being displaced from their desired positions on a support of a package when the chips are being bonded to the support.
To achieve this object, according to an exemplary embodiment of the present invention, a positioning control plate for mounting semiconductor chips at their desired positions is provided over a support of a package. In an alternate embodiment of the present invention, positioning control recesses are provided within the upper surface of the support.
A first exemplary package according to the present invention includes: a support for mounting a semiconductor component on the upper surface thereof; a positioning control plate, which is secured to the support and includes an opening or a notch; and a lead provided on the support for establishing electrical continuity between the semiconductor component mounted on the support and an external component. The positioning control plate houses at least a lower part of the semiconductor component inside the opening or the notch, thereby controlling a position of the semiconductor component on the support.
According to the first package, by housing at least the lower part of the semiconductor component inside the opening or the notch during the fabrication process, the semiconductor component can be positioned on the support with respect to the positioning control plate. Thus, even when the bond member, with which the semiconductor component and the support are bonded together, is melted at the time of heat treatment during the fabrication process, it is possible to prevent the semiconductor component from being displaced laterally on the support. As a result, the production yield can be increased noticeably.
In one embodiment of the present invention, the first package preferably further includes an outer rail, which is secured to the support to enclose the positioning control plate therein. The semiconductor component is preferably positioned on the support with respect to the positioning control plate and the outer rail. In such an embodiment, the positioning control plate need not be provided around the periphery of the package. In addition, the semiconductor component can be encapsulated easily and with a lot more certainty within the package only by hermetically covering the entire periphery of the outer rail with a plate member.
In another embodiment of the present invention, the positioning control plate is preferably formed in such a shape as allowing a melted bond member to pass through corners of the opening or the notch while the semiconductor component is being bonded to the support with the bond member. For example, the sidewalls of the opening or the notch may be partially removed to form recesses at the corners. In such a case, the bond member, which is melted at the time of heat treatment during the fabrication process, does not overflow onto the semiconductor component.
In still another embodiment, the first package preferably further includes a platelike control plate bond member, which is provided between the support and the positioning control plate and includes an opening or a notch in substantially the same shape as that of the positioning control plate. In such an embodiment, the positioning control plate can be bonded onto the support if the heat treatment is conducted approximately at the melting point of the control plate bond member.
A second package according to the present invention includes: a support for mounting a semiconductor component on the upper surface thereof; and a lead for establishing electrical continuity between the semiconductor component mounted on the support and an external component. The support includes a recess for housing at least a lower part of the semiconductor component therein, thereby controlling a position of the semiconductor component on the support.
According to the second package, by housing at least the lower part of the semiconductor component inside the recess during the fabrication process, the semiconductor component can be positioned on the support with respect to the positioning control recess. Thus, even when the bond member, with which the semiconductor component and the support are bonded together, is melted at the time of heat treatment during the fabrication process, it is possible to prevent the semiconductor component from being displaced laterally on the support.
A first semiconductor device according to the present invention includes: a support; a positioning control plate, which is secured to the support and includes an opening or a notch; a semiconductor component bonded to the support in such a manner that at least a lower part of the semiconductor component is housed inside the opening or the notch of the positioning control plate; and a lead provided on the support for establishing electrical continuity between the semiconductor component and an external component.
The first semiconductor device is formed by using the first package according to the present invention. Accordingly, the semiconductor component is not displaced from, but can be bonded at, its desired position on the support, thus increasing the production yield.
In one embodiment of the present invention, t
Maeda Masahiro
Morimoto Shigeru
Ota Yorito
Chambliss Alonzo
Paladini Albert W.
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