Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – With microwave gas energizing means
Reexamination Certificate
2000-02-11
2001-07-03
Mills, Gregory (Department: 2824)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
With microwave gas energizing means
C134S104100, C134S902000, C216S093000, C118S715000
Reexamination Certificate
active
06254720
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a wafer-processing apparatus, and especially to a wafer-processing apparatus having an auto-cleaning device.
BACKGROUND OF THE INVENTION
In the process of fabricating semiconductor devices, each wafer needs to be etched for several times. A wafer-processing apparatus is used for etching wafers therein. Please refer to
FIG. 1
schematically showing a conventional wafer-processing apparatus. An etching-solution container
11
is used for containing an etching solution, such as a buffer oxide etcher (BOE) and a buffer hydrofluoric acid solution (BHF). A gas-supplying pipe
14
is used for supplying a gas, such as an inert gas or nitrogen gas (N
2
), into said etching-solution container
11
. Because the pressure of the inert gas contained in the gas-supplying pipe
14
is relative to a level of the etching solution, the level change of the etching solution can be controlled by detecting the pressure change of the inert gas. A pressure-leveling sensor
13
is used for detecting the pressure change of gas contained in the gas-supplying pipe
14
and correspondingly outputting a level signal to a controller
12
. There are three kinds of level signals. A FIX level (FL) signal represents that the level of the etching solution is at a suitable level, a LOW level (LL) signal represents that the level of the etching solution is lower than the suitable level, and a HIGH level (HL) signal represents that the level of the etching solution is higher than the suitable level. Therefore, the controller
12
can control the level of the etching solution contained in he etching-solution container
11
according to the level signal.
The etching solution needs to be renewed after a predetermined amount of wafers has been etched by the etching solution because the etching solution is too dirty to etch more wafers.
FIG. 2
is a flowchart showing the etching-solution-renewing process of the conventional wafer-processing apparatus. After the predetermined amount of wafers has been etched by the etching solution, the controller
12
outputs a discharge signal to the discharge valve
15
so as to have the discharge valve
15
discharge the etching solution from the etching solution container
11
. Meanwhile, after the level of the etching solution is dropped below the suitable level, the pressure-leveling sensor
13
will output an LL signal to the controller
12
. When the controller
12
receives the LL signal, the controller
12
outputs a close signal to close the discharge valve
15
after a short time to ensure that the etching solution is discharged completely. Then, the controller
12
will output a charge signal to the charge valve
16
so as to have the charge valve
16
charge the etching solution into the etching-solution container
11
. The charge valve
16
will be closed by the controller
12
until a FL signal is outputted from the pressure-leveling sensor
13
.
However, the conventional wafer-processing apparatus has some drawbacks. For the cleaning aspect, the gas supplied from the gas-supplying pipe
14
has been purposely dried in advance to eliminate the damp. Therefore, the dried gas will absorb a lot of damp from the etching solution when the dried gas is supplied into the etching-solution container
11
, and the solutes contained in the damp will be dissolved out after water evaporates. These particles will usually adhere to the inner surface of the gas-supplying pipe
14
. When the particles adhering onto the wall becomes very thick, the gas-supplying pipe
14
will be choked up and the pressure-leveling sensor
13
will not detect the pressure change of the gas precisely so that the wafer-processing apparatus needs to be stopped to clean the choked gas-supplying pipe
14
. The cleaning process of the conventional wafer-processing apparatus is very time-consuming and etching-solution-wasting. In addition, when the cleaning process is done by men, it is very dangerous for the machine keepers to expose to such a harmful environment.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a novel wafer-processing apparatus such that the aforementioned limitations and difficulties encountered with the prior art can be overcome.
Specifically, it is an object of the present invention to provide a novel wafer-processing apparatus without wasting a lot of etching solution so as to reduce the cleaning cost of the wafer-processing apparatus.
Specifically, it is an object of the present invention to provide a novel wafer-processing apparatus without spending a lot of time to clean the wafer-processing apparatus.
Specifically, it is an object of the present invention to provide a novel wafer-processing apparatus which can be cleaned easily so as to prevent the machine keepers from being exposed to the harmful environment.
It is therefore another object of the present invention to provide a novel wafer-processing apparatus including an auto-cleaning device which can clean the gas-supplying pipe.
It is therefore another further object of the present invention to provide novel wafer-processing apparatus including a cleaning-solution pipe and a cup-shaped joint. The cleaning-solution pipe is used for providing a cleaning solution to clean particles remained on an inner surface of a gas-supplying pipe, and the cup-shaped joint is used for increasing a contact surface area between the gas and the cleaning solution.
A wafer-processing apparatus includes a container, a gas-supplying pipe, a pressure-leveling sensor, a controller, and an auto-cleaning device. The container is used for containing a processing solution. The gas-supplying pipe is used for supplying a gas into the container, wherein a pressure of the gas contained in the gas-supplying pipe is relative to a level of the processing solution. The pressure-leveling sensor connected to the gas-supplying pipe is used for detecting a pressure change of the gas contained in the gas-supplying pipe and correspondingly outputting a level signal. The controller electrically connected to the pressure-leveling sensor is used for outputting a discharge signal to have the container discharge the processing solution after a predetermined amount of wafers has been processed by the processing solution, and controlling a charge valve to charge the container with the processing solution in response to the level signal. The auto-cleaning device connected to the gas-supplying pipe and the pressure-leveling sensor and electrically connected to the controller, stopping the gas being supplied into the container, stopping the pressure-leveling sensor to output the level signal, and cleaning the gas-supplying pipe with a cleaning solution in response to the discharge signal, and then outputting a clean-stop signal to restart the gas being supplied into the container, to restart the pressure-leveling sensor to output the level signal, and to stop the cleaning of the gas-supplying pipe after a predetermined time.
According to the present invention, the container includes a discharge valve for discharging the processing solution therefrom in response to the discharge signal.
According to the present invention, the auto-cleaning device includes a timing controller, a triple valve, a cleaning solution pipe, a clean valve, and a control switch. The timing controller electrically connected to the controller and the pressure-leveling sensor is used for starting to count the predetermined time when the discharge signal is received, and outputting the clean-stop signal after the predetermined time. The triple valve is electrically connected to the controller and the timing controller and having a first end connected to the pressure-leveling sensor, a second end connected to the gas-supplying pipe, and a third end connected to outside, wherein the first end is conducted with the third end in response to the discharge signal and the first end is conducted with the second end in response to the clean-stop signal. The cleaning-solution pipe connected between the second end of the triple valve and th
Conlin David G.
Corless Peter F.
Dike Bronstein Roberts & Cushman
MacArthur Sylvia R.
Mills Gregory
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