Pumps – Expansible chamber type – Inlet and discharge distributors at opposite ends of tubular...
Reexamination Certificate
1997-08-25
2001-02-06
Freay, Charles G. (Department: 3746)
Pumps
Expansible chamber type
Inlet and discharge distributors at opposite ends of tubular...
Reexamination Certificate
active
06183223
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a chemical supply system adapted to discharge a predetermined quantity of a solution such as a chemical, and concerned with a chemical supply system suitable for use in coating a photo resist solution onto an outer surface of a semiconductor wafer, for example.
2. Related Art Statement
In manufacturing processes of various technical fields including a technique of manufacturing semiconductor wafers, a technique of manufacturing liquid crystal bases, a technique of manufacturing magnetic disks, a technique of manufacturing multilayer wiring bases and so forth, there have been used chemicals such as a photo resist solution, Spinion glass solution, a polyimide resin solution, pure water, a developing solution, an etching agent and an organic solvent.
For example, when the photo resist solution is coated onto the outer surface of the semiconductor wafer, the photo resist solution is dropped onto the outer surface of the semiconductor wafer in a state where the semiconductor wafer is rotated in a horizontal plane. As a chemical supply system used for coating the above-described photo resist solution, there has been used one, in which a pumping mechanism is obtained through an elastically deformable tube and bellows.
As the chemical supply system, in which the pumping mechanism is obtained through the bellows, such ones as shown in
FIG. 8
have been developed for example. FIG.
8
(A) shows a chemical supply system, in which a pump chamber
51
is formed at the outside of the bellows
50
, and which is adapted to guide the chemical in a chemical tank
53
into the pump chamber
51
and to discharge the chemical from a coating nozzle
54
through expansion or shrinkage of the bellows
50
by a driving rod
52
assembled into the bellows
50
. Furthermore, FIG.
8
(B) shows a chemical supply system, in which an expandable or shrinkable flexible tube
55
is provided in a portion of a flowpath for connecting the chemical tank
53
to the coating nozzle
54
, and a pressurizing chamber
56
provided in a tubular member disposed at the outside of the flexible tube
55
is connected to the pump chamber
51
disposed at the outside of the bellows
50
.
In Patent laid-open No.29207/1993, there is disclosed a chemical supply system for coating the chemical by use of the flexible tube or flexible film similarly to
FIG. 8
(B). In this system, the chemical is guided into the flexible film and incompressible fluid is subjected to the pumping operation by an actuator at the outside of the flexible film.
However, in the case where the bellows-type actuator is disposed at a position spaced apart from the flexible film and the incompressible fluid is supplied from the actuator to the exterior of the flexible film as described in this gazette, the system as a whole becomes large in size. Moreover, the system becomes complicated in construction, it is difficult to easily exchange parts positioned in portions being in contact with the chemical, it is uneasy to perform filling the incompressible fluid into the system, and it is uneasy to carry out the manufacturing work. Furthermore, it is difficult to control the incompressible fluid, and there may occur such a problem that, when leakage of the incompressible fluid occurs, the leakage cannot be easily detected and the system lacks the reliability.
Furthermore, in the case where the pumping operation of the chemical is directly performed by the bellows, the flow of the chemical does not occur at the rear end of the bellows
50
, and moreover, since the outer surface of the bellows
50
is irregular as being concave or convex, there is a possibility of the chemical being stagnant in the pump chamber, so that the chemical may show a change in properties due to the stagnancy, to thereby serve as a cause of raising dust during the coating.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a chemical supply system simplified in construction and excellent in reliability.
The above-described and other objects, and novel feature of the present invention will become apparent more fully from the description of the following specification in conjunction with the accompanying drawings.
The following is a brief description of the outline of typical ones out of the inventions disclosed in the present application.
That is, the chemical supply system according to the present invention is characterized in that the system comprises: a bellows having a small bellows portion made of an elastic material and a large bellows portion made of an elastic material and larger in volume change per unit displacement value in the axial direction than the small bellows portion, and elastically deformable in the axial direction; a flowpath on the side of supply, which is connected between one end portion of said bellows and a chemical receiving portion and provided therein with an on-off valve on the side of supply; a flowpath on the side of discharge connected between the other portion of said bellows and a chemical discharging portion and provided therein with an on-off valve on the side of discharge; and a driving means for elastically deforming said bellows in the axial direction to shrink said small bellows portion and expand said large bellows portion, while, for elastically deforming said bellows in the axial direction to expand said small bellows portion and shrink said large bellows portion.
Furthermore, the chemical supply system according to the present invention is characterized in that the system comprises: a flexible tube made of an elastic material and expandable or shrinkable in the radial direction; a flowpath on the side of supply, which is connected between one end portion of said flexible tube and the chemical receiving portion and provided therein with the on-off valve on the side of supply; a flowpath on the side of discharge, which is connected between the other portion of said flexible tube and the chemical discharging portion and provided therein with the on-off valve on the side of discharge; and a bellows having the small bellows portion made of the elastic material and the large bellows portion made of the elastic material and larger in volume change per unit displacement value in the axial direction than the small bellows portion, disposed at the outside of said flexible tube and elastically deformable in the axial direction; an incompressible medium enclosed between said flexible tube and said bellows; and the driving means for elastically deforming said bellows in the axial direction to shrink said small bellows portion and expand said large bellows portion, while, for expanding said small bellows portion and shrinking said large bellows portion to thereby elastically deform said flexible tube in the radial direction.
Such an arrangement may be adopted that two said bellows are provided in parallel to each other, a small bellows portion of one of the bellows is disposed adjacently to a large bellows portion of the other of the bellows, and a large bellows portion of one of the bellows is disposed adjacently to a small bellows portion of the other of the bellows.
In the chemical supply system according to the present invention, the chemical is guided into the bellows having the small bellows portion and the large bellows portion and the pumping operation is performed by the expansion on shrinkage of the bellows in the axial direction, whereby the chemical flows through the bellows, so that, even if irregular surface, i.e., concave or convex surface is present on the inner surface of the bellows, stagnancy of the chemical can be prevented from occurring.
Furthermore, in the chemical supply system according to the present invention, the flexible tube is disposed in the bellows having the small bellows portion and the large bellows portion and expanding and shrinking operation of the bellows causes the flexible tube to be elastically deformed through the incompressible medium filled in a space formed between the bellows and the flexible tube, whereby
Evora Robert Z.
Freay Charles G.
Koganei Corporation
McCormick, Paulding & Huber
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