Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
1999-06-04
2001-09-18
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C250S559400
Reexamination Certificate
active
06291814
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a slit valve with safety detect device to prevent clipping. More particularly, it relates to a safety detect device including a plurality of sensor to detect whether there are anything in the route that the seal plate moving.
2. Background of the Invention
There are many slit valves established between the plurality of different reaction chambers. The slit valves are used to act as the doors for the waiting processing wafer or processed wafer in/out the different chamber. The position of the slit valves in the prior art shown in FIG.
1
. There includes a transfer chamber
1
used to transfer the wafer from one chamber to another chamber. A load-lock chamber
3
placed beside the transfer chamber
1
to load the wafer and lock. There also includes a processing chamber
2
posited beside the other side of the transfer chamber
1
. The process chamber
2
is used to deal with the wafer, for example, etching, iron implanting or depositing the wafer. In
FIG. 1
, there are two slit valves
13
, one is posited between the transfer chamber
1
and the load lock chamber
3
, the other slit valves is posited between the transfer chamber
1
and the process chamber
2
.
The conventional slit valves can not detect that there are something between the range of the seal plate moving, because there is not any safety sensor with the conventional slit valves. If there is a wafer or robot blade in the range of the seal plate moving, the wafer or robot will be clamped and damaged. There are many wafer damaged cases by the slit valves in many semiconductor companies.
FIG. 2
shows the prior art of the slit valve comprising a clean dry air
30
used to push a seal plate
35
of a slit valve
25
. The seal plate
35
is sealed up with a slit
20
. The slit
20
is placed in the edge
10
of the transfer chamber and the edges
20
a
,
20
b
of the slit
20
is an inclined plane as shown in FIG.
2
. The seal plate
35
is in the top of the slit valve
25
and sealed up with a slit
20
, so the interval between the transfer chamber
1
and the processing chamber
2
can be sealed up.
FIG. 2
shows the wafer
40
is placed on a robot blade
45
and be transferred into a chamber through the slit
20
. When the wafer
40
is on the way into the slit
20
and the slit valve
25
wants to seal up with the slit
20
, then the wafer
40
will be clamped and damaged by the seal plate
35
of the slit valve
25
. The technique shown in
FIG. 2
exposes that there is not any safety detector on the slit valve or slit, that's why the wafer
40
always be damaged by the seal plate
35
. This kind of the wafer damaged cases are too numerous to be counted in several semiconductor companies. It should adds the safety sensor on the slit valve to avoid the damage.
SUMMARY OF THE INVENTION
The present invention relates to a slit valve with safety detect device to prevent clipping, which efficiently decrease the wafer damaged by the slit valve. The safety detect device use the different kind of transmit medium, light, infrared rays, ultra sonic, magnetism and the approximate switch to detect that there are something in the range of the seal plate moving or not. So this invention can achieve the target of the safety interlock function and to decrease the wafer damaged.
That is, the primary object of the present invention is to provide slit valve with safety detect device to achieve the safety interlock function. Further, the other object of the present invention is to provide slit valve to reduce the wafer damaged by the seal plate of the slit valve.
In order to achieve the purpose described above, we use two pair of the emitter/receiver mounted on the seal plate and the slit. The emitter and the receiver can detect that whether there are something in the range of the seal plate moving.
For the preferred embodiment, the emitter and the receiver further use the light, infrared rays, ultra sonic, magnetism and the approximate switch to act as the transmitted medium. That is the switch can set up in different type. Furthermore, this invention can be applied to different type of the slit valve by adding the safety sensor.
REFERENCES:
patent: 5579718 (1996-12-01), Freerks
Chuang Hunter
Chuang P. C.
Kuan Gary
Lu Tsung-Lin
Dougherty & Troxell
Le Que T.
Utek Semiconductor Corporation
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