Valves and valve actuation – Fluid actuated or retarded – Flexible wall expansible chamber reciprocating valve actuator
Reexamination Certificate
2000-12-22
2002-06-18
Bomberg, Kenneth (Department: 3754)
Valves and valve actuation
Fluid actuated or retarded
Flexible wall expansible chamber reciprocating valve actuator
C251S121000, C251S205000, C138S093000, C138S046000, C137S625300
Reexamination Certificate
active
06405994
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to a flow control valve and more particularly, relates to a flow control valve that contains no moving parts other than an inflatable bag positioned in a cavity of the valve.
BACKGROUND OF THE INVENTION
In a manufacturing facility, various chemicals in gaseous and liquid form are used in various fabrication processes. For instance, in a semiconductor fabrication plant, a semi-conducting substrate must be processed in a multiplicity of manufacturing steps, i.e., as many as several hundred in order to complete an integrated circuit chip. The multiplicity of manufacturing steps may include cleaning, cooling, deposition, etching and any other necessary processing steps. A variety of chemicals, including liquids and gases must be used in these steps. For instance, to clean or cool a process chamber or a wafer platform, to etch a specific feature on a substrate, to clean after each etching or deposition steps, to deposit layers of materials on a substrate, or to carry out any other processes.
The variety of chemicals used in a semiconductor facility must be handled with care since some of the processing chemicals are highly toxic and/or highly corrosive. For instance, strong acids are frequently used in an etcher for the etching of metals for forming a conductive path. Since hazardous materials are not always all consumed in chemical processes, unused hazardous chemicals must be recycled or otherwise disposed of. Due to their hazardous nature, the materials must be carefully handled during their storage and transportation to avoid personal injuries and potential fire hazard. The mechanical components used in transporting these materials should therefore be minimized such that potential exposure of personnel to the chemicals may be reduced.
Since a large number of chemicals utilized in a semiconductor fabrication facility are of the flammable or toxic nature, i.e., other than those inert gases normally utilized as purge or carrier gases, the storage and transporting of such chemicals are important aspects in the management of a fabrication facility. For instance, to avoid fire, explosion and serious personal injuries, a flammable or toxic gas must be securely stored in a safe storage facility. The storage of these gases is usually kept away from the plant personnel and thus, away from the processing equipment where they will be used. The transporting or delivery of these gases to a processing equipment therefore becomes another important aspect in the management of a fabrication plant.
A typical gas delivery system utilized in a semiconductor fabrication facility is shown in FIG.
1
. The system
10
includes a main process gas input line
12
and a main purge gas supply line
14
. A process gas, after being fed into the main process gas input line
12
, is transported through a two-way air actuated valve
16
into a main process gas supply line
18
. Off the main process gas supply line
18
, a number of two-way, diaphragm-type (hereinafter, diaphragm) control valves
20
are utilized to feed the process gas from the main supply line
18
into a three-way diaphragm control valve
24
. Into the three-way diaphragm control valve
24
, a purge gas is also fed from the main purge gas supply line
26
into a second gas inlet
23
of the three-way diaphragm control valve
24
. The purge gas, i.e., an inert gas, fed through the inlet
28
is then mixed with the process gas fed through the inlet
22
and outputted from outlet
32
of the three-way diaphragm control valve
24
. It should be noted that in the above example, the purge gas is utilized as a carrier gas for the process gas. The purge gas may also be used alone for purging the gas line without the process gas. In such application, the three-way diaphragm control valve is adjusted such that only inlet
28
is connected to outlet
32
of the valve, while inlet
22
is shut-off.
When the purge gas is used as a carrier gas, the gas mixture is sent through a gas pressure regulator
36
, a pressure transducer
38
into a second three-way diaphragm control valve
42
through inlet
40
. The process gas/carrier gas mixture then exits from either outlet
46
or
48
and is fed into a process equipment. It should be noted that in
FIG. 1
, the process equipment and the gas lines feeding to the process equipment are not shown for simplicity reasons. When the gas outlets
46
,
48
are not connected to a process equipment or to a gas delivery line, the outlets
46
,
48
are capped by a cap
50
. In the gas distribution system
10
shown in
FIG. 1
, the main process gas input line
18
is further provided with an expansion valve
60
. The expansion valve
60
is provided such that other gas output lines may be connected thereto allowing future expansion of processing equipment in the fab facility. The outlets
62
,
64
are also capped by caps
66
when the expansion valve
60
is not in use for add-on additional gas supply lines.
In the gas distribution system
10
, it is seen that a number of two-way or three-way diaphragm-type control valves, i.e.,
20
,
24
and
42
are utilized for controlling the flow of various gases, including those of the flammable or toxic nature or vacuum in the supply lines. The control valves are equipped with control handles mounted on top of the valves such that a handle may be turned either clockwise or counterclockwise to close or open the gas passage.
FIG. 1A
illustrates a cross-sectional view of an automated diaphragm valve
26
without the manually operated handle. It is seen that the diaphragm valve
26
is constructed with several moving parts, for instance, a spring
30
, a control diaphragm
34
, a spindle
44
and a sealing diaphragm
52
. Any of the moving parts
30
,
34
,
44
and
52
may fail during the operation of the valve
26
and therefore cause serious problems for the fluid supply system
10
. It is therefore desirable to provide a flow control valve for controlling fluid used in semiconductor fabrication that is essentially without any moving parts and therefore is more reliable in operation.
It is therefore an object of the present invention to provide a flow control valve that does not have the drawbacks or shortcomings of the conventional flow control valves.
It is another object of the present invention to provide a flow control valve that utilizes a minimum number of moving parts inside the valve.
It is a further object of the present invention to provide a flow control valve that can be advantageously used in semiconductor fabrication processes.
It is another further object of the present invention to provide a flow control valve that does not utilize any moving parts.
It is still another object of the present invention to provide a flow control valve for use in semiconductor manufacturing by utilizing an inflatable bag in a cavity of the valve.
It is yet another object of the present invention to provide a flow control valve by enclosing in a cavity formed by two end plates in a cylindrical-shaped housing and providing apertures in the end plates and an inflatable bag in the cavity.
It is still another further object of the present invention to provide a flow control valve that incorporates an inflatable bag wherein the bag does not substantially block a fluid flow passageway in the cavity of the valve when deflated but blocks the fluid flow passageway completely when inflated.
It is yet another further object of the present invention to provide a flow control valve incorporating an inflatable bag wherein the bag may be inflated by N
2
, air, water or oil.
SUMMARY OF THE INVENTION
In accordance with the present invention, a flow control valve for use in a fluid flow supply system that does not contain moving parts in relation to the valve housing is disclosed.
In a preferred embodiment, a flow control valve is provided which includes a valve housing that has a cylindrical-shaped wall, a first and a second end plate sealingly engaging an inner periphery of and positioned spaced-apart in the valve housing, each of the t
Bomberg Kenneth
Keasel Eric
Taiwan Semiconductor Manufacturing Co. Ltd
Tung Randy W.
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