Semiconductor device

Details Semiconductor device Semiconductor device

2002-10-31

2004-10-26

Loke, Steven (Department: 2811)

Active solid-state devices (e.g., transistors, solid-state diode

Lead frame

With bumps on ends of lead fingers to connect to semiconductor

C257S774000, C257S706000, C257S713000, C257S712000, C257S788000, C257S787000, C257S790000, C257S793000, C257S678000, C257S680000, C257S683000, C257S699000, C257S701000, C257S702000, C257S798000, C257S684000, C257S738000, C361S761000, C361S760000, C361S771000

Reexamination Certificate

active

06809407

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-336185, filed on Nov. 1, 2001, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device.
2. Related Background Art
A semiconductor wafer manufactured in front-end steps of a semiconductor fabrication process is diced and cut into individual semiconductor chips. These semiconductor chips are die-bonded and sealed with a molding resin.
A package for sealing a semiconductor chip protects a semiconductor element manufactured on the semiconductor chip. The package generally includes a lead for electrically connecting to a semiconductor element therein.
Because the functions of a semiconductor chip have been developed in recent years, the number of leads necessary for a package has increased, and thereby, the pitch between leads has decreased.
Therefore, a surface-mount-array package, that is, an SMA (Surface Mount Array) has been developed. Particularly, a BGA (Ball Grid Array) is typically used as an SMA package.
FIG. 5
is a sectional view of the package of a conventional semiconductor device
600
using a BGA. A semiconductor chip
10
, whose semiconductor element is manufactured in the front-end steps of a semiconductor fabrication process, is mounted on an insulating board
20
.
A metallic wiring (refer to
FIG. 6
) is patterned on the surface and back of the board
20
. The metallic wiring is covered with a solder resist layer
50
. The semiconductor chip
10
is bonded onto the solder resist layer
50
by an adhesive
40
and fixed to the board
20
.
The semiconductor element formed on the semiconductor chip
10
is electrically connected to the metallic wiring by a metallic wire
15
. A mold resin
25
seals the semiconductor chip
10
and metallic wire
15
to protect them.
A metallic ball
30
electrically connected to a metallic wiring is formed on the back of the board
20
.
FIG. 6
is a further enlarged sectional view showing a part of the semiconductor device
600
in FIG.
5
. In
FIG. 6
, it is shown that a metallic wiring
60
a
is formed on the surface of the board
20
and a metallic wiring
60
b
is formed on the back of the board
20
.
The metallic wirings
60
a
and
60
b
are covered with the solder resist layer
50
, and no void is present between the metallic wirings
60
a
and
60
b.
A through-hole
65
is formed on the board
20
. A metal is plated on the inside wall of the through-hole
65
. Then, the solder resist layer
50
is filled in the center of the through-hole
65
. The through-hole
65
acts as a VIA hole, and the metal on the inside wall of the through-hole
65
electrically connects the metallic wirings
60
a
and
60
b
each other.
The semiconductor device
600
shown in
FIGS. 5 and 6
is surface-mounted on a printed board or glass board after it is completed. When the semiconductor device
600
is mounted on the printed board or the like, the semiconductor device
600
is heated through a reflowing process.
The adhesive
40
and solder resist
50
, the adhesive
40
and semiconductor chip
10
, and the solder resist
50
and metallic wiring
60
a
are usually in close contact with each other.
However, it is impossible to completely prevent voids from being formed between them.
When moisture is contained in these voids, a problem occurs that the moisture in these voids evaporates during the heating process of the semiconductor device
600
and hereby, the air pressure in the voids rises. As a result, the semiconductor chip
10
separates from the board
20
.
Even when these voids are not present, the adhesive
40
, solder resist
50
, or board
20
may absorb moisture. Therefore, a problem also occurs that the moisture absorbed by the adhesive
40
, solder resist
50
, or board
20
evaporates during the heating process of the semiconductor device
600
. Also thereby, the semiconductor chip
10
separates from the board
20
.
Therefore, a semiconductor device is desired in which a semiconductor chip does not separate from a board during the heating process of a semiconductor device.
SUMMARY OF THE INVENTION
An embodiment of the present invention is provided with an electrically insulating board; conductive interconnections formed on a first face of the board and on a second face opposite to the first face; a semiconductor chip fixed to the board through at least the interconnections on the first face, said semiconductor chip having a semiconductor element electrically connected to the interconnections; a conductive bump formed on the second face of the board and electrically connected to the interconnections on the second face; and a first through-hole passing through the board to ventilate at least a part of the region between the board and the semiconductor chip.


REFERENCES:
patent: 5612576 (1997-03-01), Wilson et al.
patent: 5721450 (1998-02-01), Miles
patent: 6201707 (2001-03-01), Sota
patent: 6242802 (2001-06-01), Miles et al.

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