Optics: measuring and testing – For light transmission or absorption
Reexamination Certificate
1999-09-20
2001-05-08
Font, Frank G. (Department: 2877)
Optics: measuring and testing
For light transmission or absorption
Reexamination Certificate
active
06229611
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of detecting a transparent quartz wafer, and more particularly, to a method of detecting a transparent quartz wafer in a semiconductor equipment.
2. Description of the Prior Art
The quartz wafer is widely used as the substrate of the large-scaled thin film transistor liquid crystal display(TFT-LCD). As the demand of the liquid crystal display becomes higher, the manufacturing process of the quartz wafer becomes more important. Because the quartz wafers is almost completely transparent, there are many restrictions in performing the process of the quartz wafer by using the semiconductor equipment originally used for the process of the silicon wafer. Since the semiconductor equipment for processing the silicon wafer is highly developed at present, how to utilize the semiconductor equipment in processing the quartz wafer to benefit from the advances becomes an important issue for the semiconductor research.
Please refer to FIG.
1
.
FIG. 1
is a schematic diagram of a method of detecting a silicon wafer
12
in a semiconductor equipment
10
according to the prior art. The semiconductor equipment
10
is used to perform a specific manufacturing process over semiconductor silicon wafers and comprising a light source
14
and a optic sensor
16
for detecting the light transmitted from the light source
14
. The light source
14
may be an infrared or a red light source. The semiconductor silicon wafer
12
is moved into the semiconductor equipment
10
along a predetermined direction
18
. Because the semiconductor silicon wafer
12
itself does not allow lights to penetrate through, when the semiconductor silicon wafer
12
is moved to a predetermined position in the semiconductor equipment
10
, it will block the light
20
transmitted from the light source
14
to the optic sensor
16
and then the semiconductor equipment
10
will be switched on to perform the specific manufacturing process.
The quartz wafer is a kind of crystal material which is almost completely transparent. If performing the specific manufacturing process over the quartz wafer by using the semiconductor equipment
10
originally developed for processing the semiconductor silicon wafers, the process over the quartz wafer can not be properly controlled. Because the light
20
transmitted form the light source
14
will almost completely pass through the quartz wafer into the optic sensor
16
, and the semiconductor equipment
10
cannot detect the existence of the quartz wafer as it is moved to a predetermined position, and hence it is difficult to control the timing for switching on the specific manufacturing process.
Because the common semiconductor equipment used for processing the silicon wafers cannot be used for processing the quartz wafers, the optic sensor in the semiconductor equipment need to be replaced by other sensor in order to process the quartz wafers. Otherwise, it is necessary to purchase the whole machine specifically designed for processing quartz wafers. However, many complex machines are involved in completing the series of manufacturing processes of the TFT-LCD, it will be very time-consuming and costly to replace each of the sensors in the equipment or to change the machines.
SUMMARY OF THE INVENTION
It is therefore a primary objective of the present invention to provide a method of detecting a transparent quartz wafer in a semiconductor equipment which is used to perform a specific manufacturing process over semiconductor silicon wafers without changing the optic sensor or the whole machine.
In a preferred embodiment, the present invention provides a method of detecting a transparent quartz wafer in a semiconductor equipment comprising a light source and an optic sensor for detecting the light transmitted from the light source, wherein when the semiconductor silicon wafer is moved to a predetermined position in the semiconductor equipment, the semiconductor silicon wafer will block the light transmitted from the light source to the optic sensor and then the semiconductor equipment will be switched on to perform the specific manufacturing process when the optic detector detects that the light from the light source is blocked; the method comprising:
forming at least one thin film layer at a bottom side of the quartz wafer over which the thin film layer can absorb at least portion of light transmitted from the light source; and
moving the quartz wafer to the predetermined position in the semiconductor wherein the thin film layer at the bottom side of the quartz wafer will absorb the light transmitted from the light source to the optic sensor so as to make the optic sensor to detect the existence of the quartz wafer and then the semiconductor equipment will be switched on to perform the specific manufacturing process when the optic detector detects that the light from the light source is blocked.
It is an advantage of the present invention that the semiconductor equipment can be used to perform the manufacturing process over quartz wafers without changing its optic sensor. Therefore, the processing cost for the quartz wafer can be reduced, and the application of the semiconductor equipment becomes broader because the semiconductor equipment can be used in both semiconductor silicon wafers and the quartz wafers.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment which is illustrated in the various figures and drawings.
REFERENCES:
patent: 4643950 (1987-02-01), Ogura et al.
patent: 5340261 (1994-08-01), Oosawa et al.
patent: 5354995 (1994-10-01), Endo et al.
patent: 5358808 (1994-10-01), Nitayama et al.
patent: 5798532 (1998-08-01), Linehan
patent: 5926701 (1999-07-01), Li
patent: 5949091 (1999-09-01), Yamaguchi
patent: 5999268 (1999-12-01), Yonezawa et al.
Font Frank G.
Hsu Winston
Stafira Michael P.
United Microelectronics Corp.
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