Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – With dam or vent for encapsulant
Reexamination Certificate
1999-11-23
2001-05-15
Williams, Alexander O. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Lead frame
With dam or vent for encapsulant
C257S738000, C257S737000, C257S778000, C257S704000, C257S774000, C257S680000, C257S668000
Reexamination Certificate
active
06232652
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device, as well as a manufacturing method thereof, in which semiconductor elements are housed in a package. More specifically, the present invention relates to a structure of a semiconductor device that has a heat spreader, a cap, or the like and in which the semiconductor elements are housed in a hollow cavity, and a manufacturing method thereof.
2. Background Art
FIG. 8
shows an example structure of a conventional semiconductor device in package form. For example, the conventional semiconductor device is configured by a BGA substrate
7
, a semiconductor chip
5
that is flip-chip-bonded to the BGA substrate
7
via solder bumps, a sealing member capable of improving the reliability of the above bonding, solder balls
8
that are arranged on the back surface of the BGA substrate
7
to obtain electrical connections with an external apparatus, a heat spreader
1
for dissipating heat outward that is generated in the semiconductor chip
5
, a heat-dissipating resin
6
that accelerates heat conduction between the semiconductor chip
5
and the heat spreader
1
, a ring
2
and adhesive tapes
3
that join the BGA substrate
7
and the heat spreader
1
to each other while providing a prescribed gap in between.
In a manufacturing process of the above-type of semiconductor device, the temperature becomes higher than the solder melting temperature, for example, in a step in which sealing is made with the heat spreader or the cap made of a metal such as copper, ceramics, an organic material, or the like and in subsequent steps in which, for example, solder balls are formed or the semiconductor device is mounted on a board by reflow. There is a problem that in those steps sealed air thermally expands to possibly deform or peel off the heat spreader
1
.
FIG. 9
a
and
9
b
illustrate such a state. Peeling occurs between the heat spreader
1
and the heat-dissipating resin
6
or between the heat-dissipating resin
6
and the semiconductor chip
5
, which results in a problem that the heat dissipation characteristic of the semiconductor device is deteriorated.
In case of improving the effect of dissipating heat outward by providing radiation fins on the semiconductor device, it is necessary to increase the heat conductivity from the semiconductor device to the radiation fins.
When the semiconductor device is manufactured, the heat spreader and the ring are attached by thermal pressure bonding using a pressurizing head. There is a problem that the semiconductor chip may be damaged in this operation. Further, since the heat-dissipating resin starts to set immediately, voids may be produced inside the heat-dissipating resin, deteriorating the heat dissipation characteristic.
Further, when the semiconductor device is manufactured, it is necessary to peel off a cover film that is provided on that surface of each of the heat spreader and the ring to which a thermosetting adhesive tape, for example, adheres.
The present invention has been made to solve the above problems in the conventional art, and an object of the invention is therefore to provide a semiconductor device and a manufacturing method thereof which can prevent damaging of a semiconductor chip of the semiconductor device as well as deterioration in the heat dissipation characteristic of the semiconductor device.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a semiconductor device comprises a planar substrate and a semiconductor chip mounted on the planar substrate approximately at the center thereof. Further, the semiconductor devise comprises an annular ring member, annular adhesive tapes, and a heat spreader plate that are laminated on the substrate so as to form a hollow cavity that houses the semiconductor chip, and at least one of the adhesive tapes has a slit to serve as an air vent.
In another aspect of the present invention, the annular ring member has a slit to serve as an air vent.
According to still another aspect of the present invention, in a method of manufacturing a semiconductor device, a semiconductor chip is mounted on a planar substrate approximately at the center thereof. An annular ring member, annular adhesive tapes, and a heat spreader plate are laminated on the planar substrate, and bonded to the planar substrate by applying pressure only above the position of the annular adhesive tapes by using a pressurizing head having an annular protrusion.
Other and further objects, features and advantages of the invention will appear more fully from the following description.
REFERENCES:
patent: 5414293 (1995-05-01), Broom
patent: 5652463 (1997-07-01), Weber et al.
patent: 5692296 (1997-12-01), Variot
patent: 5760467 (1998-06-01), Itihasi
patent: 5905301 (1999-05-01), Ichikawa et al.
patent: 5909057 (1999-06-01), McCormick et al.
patent: 63-84051 (1988-04-01), None
patent: 2-222564 (1990-09-01), None
patent: 6-151620 (1994-05-01), None
patent: 6-169026 (1994-06-01), None
McDermott & Will & Emery
Mitsubishi Denki & Kabushiki Kaisha
Williams Alexander O.
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