Active solid-state devices (e.g. – transistors – solid-state diode – Physical configuration of semiconductor – With peripheral feature due to separation of smaller...
Reexamination Certificate
2000-11-17
2003-01-14
Paladini, Albert W. (Department: 2827)
Active solid-state devices (e.g., transistors, solid-state diode
Physical configuration of semiconductor
With peripheral feature due to separation of smaller...
C257S724000, C257S787000, C257S797000
Reexamination Certificate
active
06507092
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to semiconductor devices and methods of producing the same and semiconductor chips and methods of producing the same, and more particularly to a semiconductor device having a chip size package (CSP) structure, in which a sealing resin is formed on a semiconductor chip, and a method of producing the same, and a semiconductor chip for such a semiconductor device and a method of producing the same.
Recently, attempts have been made to produce a smaller size semiconductor device having a higher density in order to meet a demand for a smaller electronic device and apparatus. Therefore, a semiconductor device having a so-called CSP structure is employed, the semiconductor device being downsized by being shaped as close to a semiconductor chip as possible.
In order to obtain a package of a real chip size and to increase a production efficiency, so-called wafer level packaging is proposed. According to the wafer level packaging, a substrate is packaged with a plurality of semiconductor chips formed thereon, and the as-packaged substrate is divided into individual small-size semiconductor devices.
2. Description of the Related Art
FIG. 1
shows a semiconductor device
1
A obtained by conventional wafer level packaging. The semiconductor device
1
A is a semiconductor device of a so-called CSP type and includes a semiconductor chip
2
A, a sealing resin
5
A and solder balls
4
. The semiconductor chip
2
A has a plurality of external terminals
3
formed protrusively on its upper surface. The sealing resin
5
A is formed on the upper surface of the semiconductor chip
2
A so that the upper portions of the external terminals appear partially from the sealing resin
5
A. The solder balls
4
are formed on the portions of the external terminals
5
A appearing from the sealing resin
5
A.
When heat is applied to the semiconductor chip
2
A and the sealing resin
5
A, which have different expansion coefficients, the sealing resin
5
A may come off the semiconductor chip
2
A because of a difference in thermal expansion therebetween. In order to prevent the sealing resin
5
A from coming off the semiconductor chip
2
A, the peripheral portion of the semiconductor chip
2
A is formed into a rectangular step-like portion
6
having an L-shaped cross section. According to this structure, the step-like portion
6
is filled with the sealing resin
5
A when the sealing resin
5
A is formed, so that the sealing resin
5
A in the step-like portion
6
produces an anchoring effect. This increases the bonding strength of the sealing resin
5
A and the semiconductor chip
2
A so as to prevent the sealing resin
5
A from coming off the semiconductor chip
2
A.
FIGS. 2A through 2G
are diagrams for illustrating the outline of the production method of the semiconductor device
1
A having the above-described structure. According to
FIGS. 2A through 2G
, especially, a method of forming the step-like portion
6
is mainly shown. In the production of the semiconductor device
1
A, a method of simultaneously obtaining a plurality of semiconductor devices from one semiconductor substrate (hereinafter, a wafer) is taken. A more specific description of the method will be given in the following. First, the circuits of the individual semiconductor chips
2
A are formed on the surface (hereinafter, a circuit-containing surface) of the wafer
10
. Then, the external terminals
3
are formed on the circuit-containing surface, and a resin film of polyimide or the like (not shown) is formed on the circuit-containing surface for the protection thereof.
Next, as shown in
FIGS. 2A through 2C
, rectangular grooves
12
are formed in the wafer
10
along predetermined dicing lines (cutting lines) on the circuit-containing surface thereof by employing a dicing saw for grooving (hereinafter, a grooving dicing saw)
11
A. After the rectangular grooves
12
are formed, the sealing resin
5
A is formed on the same surface on which the rectangular grooves
12
are formed as shown in FIG.
2
D. At this point, the rectangular grooves
12
are filled with the sealing resin
5
A. Further, the sealing resin
5
A is formed so that the upper portions of the protrusion electrodes appear partially from the sealing resin
5
A.
Next, as shown in
FIGS. 2E and 2F
, a dicing process is performed on the wafer
10
using a dicing saw for cutting (hereinafter, a cutting dicing saw)
13
. The thickness of the cutting edge of the cutting dicing saw
13
is narrower than that of the grooving dicing saw
11
A.
Therefore, as shown in
FIG. 2G
, each individual semiconductor device
1
A obtained after the dicing process includes the step-like portion
6
, which is formed as a result of cutting into two each of the rectangular grooves
12
filled with the sealing resin
5
A. Since the rectangular grooves
12
are filled with the sealing resin
5
A as previously described, the step-like portions
6
formed after the dicing process are also filled with the sealing resin
5
A. Therefore, the sealing resin
5
A produces the above-described anchoring effect in each of the step-like portions
6
so as to be prevented from coming off each of the semiconductor chips
2
A.
FIG. 3
shows a semiconductor device
1
B having another structure obtained by the conventional wafer level packaging.
FIGS. 4A through 4G
are diagrams showing the outline of the production method of the semiconductor device
1
B. In
FIGS. 3 through 4G
, the same elements as those of previously-described
FIGS. 1 through 2G
are referred to by the same numerals and a description thereof will be omitted.
The semiconductor device
1
B shown in
FIG. 3
is also a semiconductor device of the CSP type, and has the same basic structure as the semiconductor device
1
A shown in FIG.
1
. However, according to the semiconductor device
1
A shown in
FIG. 1
, the semiconductor chip
2
A includes the step-like portion
6
filled with the sealing resin
5
A so that the semiconductor chip
2
A and the sealing resin
5
A are bonded strongly by the anchoring effect produced by the sealing resin
5
A.
On the other hand, according to the semiconductor device
1
B shown in
FIG. 3
, the peripheral portion of the semiconductor chip
2
A is formed into a tapered portion
7
covered with the sealing resin
5
A. Also according to this structure, an area in which the sealing resin
5
A and the semiconductor chip
2
A are bonded is increased so as to increase the bonding strength thereof. Therefore, the sealing resin
5
A is prevented from coming off the semiconductor chip
2
A.
In order to produce the semiconductor device
1
B having the above-described tapered portion
7
, a grooving dicing saw
11
B is employed. The cross section of the edge portion of the grooving dicing saw
11
B has a triangular shape as shown in
FIGS. 4A through 4C
. Triangular grooves
14
are formed in the wafer
10
along predetermined dicing lines (cutting lines) on the circuit-containing surface thereof by employing the grooving dicing saw
11
B. After the triangular grooves
14
are formed, the sealing resin
5
A is formed as shown in
FIG. 4D
, so that the triangular grooves
14
are filled with the sealing resin
5
A.
Next, as shown in
FIGS. 4E and 4F
, the dicing process is performed on the wafer
10
using the cutting dicing saw
13
. The thickness of the cutting edge of the cutting dicing saw
13
is narrower than that of the grooving dicing saw
11
B. Therefore, as shown in
FIG. 4G
, each individual semiconductor device
1
B obtained after the dicing process includes the tapered portion
7
, which is formed as a result of cutting into two each of the triangular grooves
14
filled with the sealing resin
5
A.
Since the triangular grooves
14
are filled with the sealing resin
5
A as previously described, the tapered portions
7
formed after the dicing process are also filled with the sealing resin
5
A. Therefore, the sealing resin
5
A produces the above-described anchoring effect in each of the tapered portions
7
so as to
Fukasawa Norio
Hozumi Takashi
Kawahara Toshimi
Armstrong Westerman & Hattori, LLP
Chambliss Alonzo
Fujitsu Limited
Paladini Albert W.
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