Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Electromagnetic or particle radiation
Reexamination Certificate
2002-03-28
2004-09-28
Clark, Sheila V. (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Electromagnetic or particle radiation
C257S787000, C257S778000, C257S434000, C438S127000
Reexamination Certificate
active
06798031
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to semiconductor devices, and more particularly, to a semiconductor device, which unifies a light receiving element and a lens for photographing as a package, and is suitable for photographing.
2. Description of the Related Art
Recently, a cellular phone and a mobile personal computer in which a small sized camera is built have been developed. For instance, it is possible to take a picture of a person using the cellular phone by the small sized camera built in the cellular phone, so as to take a picture in the cellular phone as image data, and to transmit the image data to an opponent of the person. Such a small sized camera generally comprises a C-MOS sensor and a lens. There is a demand for miniaturizing the small sized camera for the cellular phone as well as miniaturizing the cellular phone and the mobile personal computer. A semiconductor device package formed by unifying the light receiving element and the lens has been developed to meet the demand for miniaturizing such the small sized camera.
FIG. 1
is a cross-sectional view showing a conventional semiconductor device package unifying a lens for photographing and a semiconductor chip having the C-MOS sensor. In the semiconductor device package shown in
FIG. 1
, a semiconductor chip
1
having a C-MOS sensor is mounted on a printed circuit board
2
which is rigid and wire-bonded to a pattern wire
2
a
of the printed circuit board
2
, in a state where a light-receiving surface
1
a
of the chip
1
is top.
A lens
3
for photographing is attached to a housing
4
. The housing
4
is fixed on the printed circuit board
2
in a state where the lens
3
is arranged in a designated position above the light-receiving surface
1
a
of the chip
1
. Therefore, the semiconductor device package for the small-sized camera shown in
FIG. 1
has a structure where the semiconductor chip is mounted on the board and the lens is arranged above the chip. Further, an IR filter
5
is arranged between the lens
3
and the semiconductor chip
1
.
A positioning pin
6
is formed on a base of the housing
4
. The housing
4
is precisely positioned on the printed circuit board
2
by inserting the pin
6
in a positioning hole
7
provided in the printed circuit board
2
. Thus, it can be carried out to position the lens
3
attached to the housing
4
relative to the semiconductor chip
1
which is mounted on the printed circuit board
2
.
In the semiconductor device package having the above-mentioned structure, another printed circuit board
8
is arranged under the printed circuit board
2
in a case where an electronic part
9
such as a capacitor, resistor, and the like is mounted. That is, the printed circuit board
2
having the semiconductor chip
1
and the housing
4
is mounted on the printed circuit board
8
, and the electronic part
9
is mounted on the printed circuit board
8
.
However, the above-mentioned conventional semiconductor device package has the following disadvantages due to its structure.
First of all, referring to
FIG. 2
which is a plan view showing an arrangement of parts of the semiconductor device package of
FIG. 1
, the electronic part
9
is arranged outside of the printed circuit board
2
on which the semiconductor chip
1
and the housing
4
are mounted, in a case where the electronic parts
9
are mounted on the printed circuit board
8
. Accordingly, the printed circuit board
8
is bigger than the printed circuit board
2
, so that the size of the entire semiconductor package is increased.
Secondly, as to a manufacturing process of the semiconductor chip having a light-receiving element, a back of the semiconductor chip
1
is ground by a grinder in order to reduce a thickness of the semiconductor chip
1
.
Therefore, the thickness of the semiconductor chip
1
fluctuates on an individual wafer basis. A range of the fluctuation is normally between plus 15 &mgr;m and minus 15 &mgr;m and an allowable range of the fluctuation is between about plus 30 &mgr;m and minus 30 &mgr;m.
In case of that the thickness of the semiconductor chip
1
is fluctuated, a distance between a light-receiving surface
1
a
of the semiconductor chip
1
and the lens
3
is also fluctuated.
The lens
3
is arranged at a designated distance from the surface of the printed circuit board
2
and the light-receiving surface
1
a
is arranged at the distance corresponding to the thickness of the semiconductor chip
1
from the surface of the printed circuit board
2
. Therefore, the light-receiving surface
1
a
of the semiconductor chip
1
approaches the lens
3
when the thickness of the semiconductor chip
1
is increased. The light-receiving surface
1
a
of the semiconductor chip
1
is remote from the lens
3
when the thickness of the semiconductor chip
1
is decreased.
The distance between the lens
3
and the light-receiving surface
1
a
of the semiconductor chip
1
is set equal to a focal length of the lens
3
, so that a picture taken by the lens
3
is formed on the light-receiving surface
1
a
precisely. Accordingly, if the distance between the light-receiving surface
1
a
and the lens
3
is fluctuates as described above, there is a problem in that an unfocused state happens and the picture is out of focus.
Thirdly, in case of that the semiconductor chip
1
is mounted on the printed circuit board
2
, the semiconductor chip
1
is glued and fixed on a surface of the printed circuit board
2
by a die apparatus.
The die apparatus holds the semiconductor chip
1
by suctioning the surface of the semiconductor chip
1
, namely a face on which the light-receiving element is formed, and carries and places the semiconductor chip
1
on the printed circuit board
2
. Accordingly, it is impossible to recognize a face on which the light-receiving element is formed by image recognition, because the surface of the semiconductor chip is covered with a suctioning apparatus. Therefore, an external form of the semiconductor chip
1
is recognized by image recognition and the external form is a used as a reference to decide a position of the semiconductor chip on the printed circuit board.
However, a positional relationship between the light-receiving surface
1
a
of the semiconductor chip
1
and the external form is not always the same. That is, the external form of the semiconductor chip
1
is defined when a wafer is divided by dicing so as to individualize the semiconductor chip
1
. The position of the light-receiving surface relative to the external form of the semiconductor chip
1
is changed by changing the cutting position by dicing. Therefore, there may be a case in which a focal position of the lens
3
is not precisely coincident with a center of the light-receiving surface
1
a.
Fourthly, a pad for wire-bonding, formed as a part of a wire pattern
2
a
, must be arranged around the semiconductor chip because the semiconductor chip is mounted on the printed circuit board by wire-bonding. Therefore, it is necessary to provide a place on the printed circuit board
2
where the bonding pad is arranged. The above-mentioned arrangement is an obstacle to miniaturize the semiconductor device package.
Lastly, the substantially necessary thickness as the semiconductor device package is equal to the sum of the focal distance of the lens
3
and the thickness of the semiconductor chip
1
. However, according to the above-mentioned conventional semiconductor apparatus package, the actual thickness of the semiconductor device package is equal to the sum of the focal distance of the lens
3
, the thickness of the semiconductor chip
1
, and the thickness of the printed circuit board
2
, because the printed circuit board
2
is arranged at the opposite side of the lens
3
regarding the semiconductor chip
1
.
Therefore, the thickness of the semiconductor device package is increased by the thickness of the printed circuit board
2
. Besides, when the electronic parts
9
are mounted, the actual thickness of the semiconductor d
Aoki Hiroshi
Honda Toshiyuki
Kaiya Hiroshi
Kobayashi Izumi
Moriya Susumu
Armstrong Kratz Quintos Hanson & Brooks, LLP
Clark Sheila V.
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