Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package
Reexamination Certificate
1999-04-20
2001-07-10
Smith, Matthew (Department: 2825)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
C257S778000, C257S787000, C257S788000
Reexamination Certificate
active
06259154
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a BGA (Ball Grid Array) package-type semiconductor device using a TAB (TApe Bonding) tape and a method of manufacturing the same.
As one of the package structures for semiconductor devices, a Tape-BGA package-type semiconductor device (to be referred to as a BGA package hereinafter) is known.
For example, as shown in
FIG. 8
, this BGA package
1
has a semiconductor chip
2
and a TAB tape
3
having inner leads
4
to be connected to electrodes
2
a
of the semiconductor chip
2
by inner lead bonding.
A metal (e.g., a Cu alloy) stiffener
5
and a heat dissipation plate
6
formed of a metal plate member (e.g., a Cu alloy member) are stacked on the lower surface of the TAB tape
3
. The stiffener
5
is formed into a frame to correct the warp of the TAB tape
3
, thereby maintaining the flatness thereof. The heat dissipation plate
6
is called a heat spreader (H/SP) for dissipating heat generated by the semiconductor chip
2
. In
FIG. 8
, a chip mounting portion
6
a
is formed at the center of the surface of the heat dissipation plate
6
having an entirely rectangular shape. The stiffener
5
forms a frame having an opening that surrounds the chip mounting portion
6
a.
In the BGA package
1
described above, as shown in
FIGS. 9 and 10
, the inner leads
4
of the TAB tape
3
are bonded to the electrodes
2
a
of the semiconductor chip
2
, and the stiffener
5
is adhered to the lower surface of the TAB tape
3
with an adhesive
8
to maintain the flatness thereof. After that, the bonding portions of the electrodes
2
a
of the semiconductor chip
2
and the inner leads
4
are coated with a resin
9
. Solder balls
10
are formed at portions of the surface of the TAB tape
3
described above which correspond to the respective leads.
The heat dissipation plate
6
is set to oppose the lower surfaces of the semiconductor chip
2
and stiffener
5
. The semiconductor chip
2
and stiffener
5
are pressed against the heat dissipation plate
6
through a conductive paste
11
such as Ag paste and an adhesive
12
, respectively, so that the semiconductor chip
2
, stiffener
5
, and heat dissipation plate
6
are integrally adhered to each other.
In the conventional BGA package
1
described above, since the frame-like stiffener
5
is formed of a metal plate material made of a Cu alloy or the like, the weight of the whole package increases, and demands for a smaller size and smaller weight cannot be satisfied. If such a BGA package
1
is relatively heavy, when the solder balls (solder bumps)
10
are fused when packaging the BGA package
1
, they cannot withstand the weight of the BGA package
1
but are crushed flat to form bridges connected to the adjacent solder balls
10
. If the BGA package
1
is heavy, a bonding strength that can withstand a drop impact test for the package cannot be obtained in design.
In the conventional BGA package
1
described above, since the heat dissipation plate
6
and stiffener
5
are formed of metal plate members, the package weight increases, as described above. In addition, the material cost per product increases.
In the BGA package
1
having the above structure, after the stiffener
5
and TAB tape
3
are adhered to each other with the adhesive
8
, the semiconductor chip
2
and stiffener
5
are adhered to the heat dissipation plate
6
with the conductive paste
11
and adhesive
12
, respectively, resulting in the two adhering steps. As these separate adhering steps are required, the manufacturing process becomes complicated, and the production efficiency is poor.
When the stiffener
5
and heat dissipation plate
6
are fixed to each other by adhesion in this manner, the precision may be degraded due to a positional shift occurring during adhesion. Also, the adhering steps described above take a long hardening time until the adhesives harden, degrading the productivity.
In the BGA package
1
described above, the metal stiffener
5
is adhered to the TAB tape
3
. As an excessively large difference is present in thermal expansion between the stiffener
5
and TAB tape
3
, during the manufacture or during mounting this package onto a printed circuit board, a stress remains between the solder balls
10
and the mounting board. Then, the long-term reliability decreases.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above situations, and has as its object to provide a semiconductor device in which downsizing and weight reduction of the whole package are achieved, the manufacturing cost including the material cost is decreased, and the manufacturing process is simplified to improve the production efficiency, and a method of manufacturing the same.
In order to achieve the above object, according to the present invention, there is provided a semiconductor device comprising a semiconductor chip, a TAB tape having leads to be connected to electrodes of the semiconductor chip, a stiffener adhered to a lower surface of the TAB tape to maintain flatness of the TAB tape, and a heat dissipation plate having a surface on which the semiconductor chip and the stiffener surrounding the semiconductor chip are adhered to dissipate heat generated by semiconductor chip, wherein the stiffener is molded with a synthetic resin material.
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patent: 5612576 (1997-03-01), Wilson et al.
patent: 5835355 (1998-11-01), Dordi
patent: 5841194 (1998-11-01), Tsukamoto
patent: 5939778 (1999-08-01), Boutin et al.
patent: 6002171 (1999-12-01), Desai et al.
patent: 6166434 (2000-12-01), Desai et al.
patent: 45-36771 (1970-11-01), None
patent: 4-167452 (1992-06-01), None
patent: 9-246315 (1997-09-01), None
Tummala R.R., Rymaszewski E.J., Klopfenstein A.G., “Microelectronic Packaging Handbook, Semiconductor Packaging, Part II”, second edition, pp. 222, 223,244, 258, and 259, 1997.
Hayes Soloway Hennessey Grossman & Hage PC
NEC Corporation
Rocchegiani Renzo N.
Smith Matthew
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