Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor – Assembly of plural semiconductive substrates each possessing...
Reexamination Certificate
2001-06-25
2003-06-24
Zarabian, Amir (Department: 2822)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
Assembly of plural semiconductive substrates each possessing...
C438S108000, C438S109000, C438S110000, C438S459000, C257S778000
Reexamination Certificate
active
06582991
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device including semiconductor chips packaged therein, and more particularly to a semiconductor device including semiconductor chips packaged therein with high density where the semiconductor chips are buried in a printed wiring board, and a method for fabricating such a semiconductor device.
In recent years, electronic equipment, in particular portable electronic equipment, has been downsized at rapid paces. To keep pace with this, downsizing of semiconductor devices is also in progress. For example, small-size semiconductor packages such as chip scale packages (CSP) have been commercialized. Also commercialized have been semiconductor packages in which semiconductor chips are stacked on top of each other to reduce the packaging area of the semiconductor chips. Moreover, for attainment of further thinned electronic equipment, there have been developed semiconductor devices including semiconductor chips packaged therein with high density where the semiconductor chips are buried in a multilayer wiring board.
Hereinafter, as a conventional example, a semiconductor device and a fabrication method thereof disclosed in Japanese Laid-Open Patent Publication No. 4-373157 will be described with reference to
FIGS. 30A through 30C
.
FIGS. 30A through 30C
are cross-sectional views illustrating process steps of a conventional method for fabricating a semiconductor device.
As shown in
FIG. 30A
, an insulating board
13
having an opening
13
a
is bonded to the top surface of a first circuit board
10
. The first circuit board
10
has first and second wirings
11
and
12
formed on the top and bottom surfaces thereof. A semiconductor chip
14
is mounted on the exposed top surface of the first circuit board
10
inside the opening
13
a
so that the circuit formation surface of the semiconductor chip
14
faces the top surface of the first circuit board
10
, that is, by face-down bonding. To state more specifically, bumps
15
, which are formed on electrodes (not shown) provided on the circuit formation surface of the semiconductor chip
14
, are bonded to the first wiring
11
with conductive paste
16
. A first resin layer
17
is then formed between the semiconductor chip
14
and the first circuit board
10
.
As shown in
FIG. 30B
, a second resin layer
18
is formed on the sides and the top surface of the semiconductor chip
14
so that the opening
13
a
is filled completely. Thereafter, as shown in
FIG. 30C
, a second circuit board
20
is bonded to the top surfaces of the insulating board
13
and the second resin layer
18
. The second circuit board
20
has third and fourth wirings
21
and
22
formed on the top and bottom surfaces thereof.
By the fabrication through the process steps shown in
FIGS. 30A through 30C
, completed is a semiconductor device where the semiconductor chip
14
is buried inside the multilayer circuit board composed of the first circuit board
10
, the insulating board
13
, the second circuit board
20
, and the like.
The conventional semiconductor device described above has the following problems. The opening
13
a
must be formed through the insulating board
13
constituting the multilayer circuit board, to mount the semiconductor chip therein. This increases the number of fabrication steps and thus increases the cost. In addition, the first wiring
11
may be contaminated with an adhesive material and the like flowing out during the bonding of the insulating board
13
to the first circuit board
10
. This makes it difficult to keep clean the connecting portions of the first wiring
11
with the semiconductor chip
14
, and thus to ensure the electrical connection between the first wiring
11
and the semiconductor chip
14
. Another problem is that separation is likely to occur at the interface between the insulating board .
13
having the opening
13
a
and the second resin layer
18
filled in the opening
13
a
. This makes it difficult to attain a good-quality semiconductor device.
In order to reduce the thickness of the entire semiconductor device including semiconductor chips packaged therein, the semiconductor chips must be thin. A thin semiconductor chip is more susceptible to external damage and more easily warped losing flatness, compared with a thick semiconductor chip. Therefore, when a thin semiconductor chip is used for the conventional semiconductor device, difficulty arises during the formation of bumps and the mounting of the semiconductor chip in the board. In other words, in order to prevent a semiconductor chip from external damage and warping in the conventional semiconductor device, a thick semiconductor chip must be mounted. This increases the thickness of the multilayer circuit board constituting the conventional semiconductor device. In addition, since a thick semiconductor chip is buried with a resin in the multilayer circuit board, heat generated due to the operation of the semiconductor chip is less easily dissipated outside.
SUMMARY OF THE INVENTION
An object of the present invention is providing a thin semiconductor device with high reliability and high heat dissipation in which semiconductor chips are packaged with high density and, and a method for easily fabricating such a semiconductor device.
The first method for fabricating a semiconductor device of the present invention includes the steps of: (1) mounting a semiconductor chip on a first surface of a substrate, the substrate having wiring formed on the first surface, so that a circuit formation surface of the semiconductor chip faces the first surface of the substrate and that an electrode provided on the circuit formation surface is connected with the wiring; (2) forming a sealing resin layer on the first surface of the substrate to cover the semiconductor chip; and (3) grinding the sealing resin layer and the semiconductor chip starting from a surface opposite to the circuit formation surface to thin the semiconductor chip.
According to the first method for fabricating a semiconductor device, a semiconductor chip is first mounted on the first surface of the substrate so that the circuit formation surface of the semiconductor chip faces the first surface of the substrate, and then the semiconductor chip is ground starting from the surface thereof opposite to the circuit formation surface, to be thinned. Accordingly, it is possible to handle the original thick semiconductor chip during the mounting of the semiconductor chip on the substrate. Thus, formation of the bumps on the semiconductor chip, the mounting of the semiconductor chip on the substrate, and the like can be performed easily and reliably while preventing occurrence of external damage and warp. Moreover, since the semiconductor chip mounted on the substrate is thinned by grinding, heat generated due to the operation of the semiconductor chip is easily dissipated. In addition, when such semiconductor chips are layered in a semiconductor device, the thickness of the resultant semiconductor device can be small. As a result, it is possible to easily fabricate a thin semiconductor device with high reliability and high heat dissipation in which semiconductor chips are packaged with high density.
According to the first method for fabricating a semiconductor device, the semiconductor chip is ground while being surrounded and sealed with a resin. This suppresses occurrence of external damage on the semiconductor chip due to the grinding, and thus a semiconductor device can be fabricated without deterioration in quality.
According to the first method for fabricating a semiconductor device, the semiconductor chip is mounted on the substrate and then covered with the resin layer. This simplifies the fabrication process compared with the conventional technique where an opening is formed through the insulating layer on the substrate and the semiconductor chip is buried in the opening together with the resin. This also prevents occurrence of the prior art problem of separation at the interface between the insulating layer having th
Arai Yoshiyuki
Homma Hajime
Kawabata Takeshi
Maeda Kenji
Naraoka Hiroki
Matsushita Electric - Industrial Co., Ltd.
Nixon & Peabody LLP
Studebaker Donald R.
Vockrodt Jeff
Zarabian Amir
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