Fluid handling – Diverse fluid containing pressure systems – Gas pressure storage over or displacement of liquid
Reexamination Certificate
1999-08-06
2001-01-23
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Diverse fluid containing pressure systems
Gas pressure storage over or displacement of liquid
C095S262000, C096S219000, C096S220000
Reexamination Certificate
active
06176252
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for supplying a liquid, and more particularly to an apparatus for supplying a photoresist liquid in a semiconductor manufacturing process.
BACKGROUND OF THE INVENTION
In the semiconductor manufacturing process, a layer of the photoresist liquid is coated on a wafer by a spin-coater before a photolithographic process. Because the demand for the semiconductor device is severe, the yield of the wafer may be reduced if there is an impurity remained on the wafer. That is, if any particle or bubble is retained in the photoresist liquid, then the quality of the wafer may be reduced. Therefore, the impurities of the photoresist liquid must be removed before that the liquid is applied on the surface of the wafer.
Please refer to
FIG. 1
which is a diagram showing the apparatus for supplying the photoresist liquid of the prior art. The conventional apparatus includes a container
12
filled with the photoresist liquid
11
and a filter
15
. The container
12
is placed straight in a hermetic receiver
13
. A pipe
14
is inserted into the container
12
and connected to the filter
15
. A nitrogen gas (N
2
) is introduced into the receiver
13
through a valve
16
. After the gas enters the receiver
13
, the photoresist liquid
11
is discharged from the container
12
because of the pressurization
17
of the nitrogen gas. The photoresist liquid
11
enters the filter
15
through the pipe
14
. The impurities of the photoresist liquid, including particles and bubbles, are removed by the filter
15
. Finally, the photoresist liquid
11
is introduced into the spin-coater and then coated on the wafer.
However, there are two shortcomings of the apparatus for supplying the photoresist liquid in the prior art. First, there is a recess at the bottom
18
of the container
12
so the bottom surface of the container is uneven. If the pipe
14
is short and can not be inserted into the recess, there will be a distance between the pipe
14
and the bottom
18
of the container
12
. Therefore, the photoresist liquid in the recess can not be discharged from the container
12
, and a lot of photoresist liquid
11
will be retained in the container
12
. On the contrary, if the pipe
14
is long enough to reach the bottom
18
of the container
12
, the photoresist liquid
11
may not be discharged easily. That will waste a lot of photoresist liquid.
Second, all kinds of impurities must be removed by the filter
15
. The only one filter may be exchanged frequently and the cost of the semiconductor chip will be increased. Therefore, it is tried by the applicant to deal with the problems encountered with the prior art.
SUMMARY OF THE INVENTION
A major object of the present invention is to provide an apparatus for supplying the photoresist liquid in the semiconductor manufacturing process.
Another object of the present invention is to provide a kind of placement of a container filled with the photoresist liquid for allowing the photoresist liquid to be totally discharged from the container.
Another object of the present invention is to provide an apparatus for removing the impurities of the photoresist liquid.
The improvements made in the present invention includes the placement of the container filled with the photoresist liquid and the filters.
According to tile present invention, the apparatus for supplying a liquid in a semiconductor manaufacturing process includes a container storing the liquid therein and a gas inlet for introducing a gas and a liquid outlet for discharging the liquid pressurized by the gas. The apparatus further includes a first filter connected to the liquid outlet of the container for removing an impurity of the liquid.
The container is slopingly positioned so that the liquid outlet of the container is inclined downwardly to allow the liquid to be totally discharged therefrom. The liquid is a photoresist liquid and the gas is a chemically inert gas. Certainly, the gas is nitrogen (N
2
) gas. The impurity of the liquid contains a particle and a bubble.
The first filter includes a plurality of plates extending outwardly from an inner surface of the first filter for allowing the liquid to be agitated therein, an outlet arranged at the bottom of the first filter for discharging a precipitated impurity, and a plurality of exhaust valves respectively arranged adjacent to the plates for allowing a gaseous impurity to be released from the first filter.
The apparatus further includes a second filter connected to the first filter for filtering out a residual impurity of the liquid.
The present invention may best be understood through the following description with reference to the accompanying drawings, in which:
REFERENCES:
patent: 5814151 (1998-09-01), Lee et al.
patent: 5871028 (1999-02-01), Liu
patent: 6014995 (2000-01-01), Agnew
patent: 6021921 (2000-02-01), Lan et al.
Allen Dyer Doppelt Milbrath & Gilchrist, P.A.
Michalsky Gerald A.
Winbond Electronics Corp.
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