JPH0736378B2 - High viscosity resist pump - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a resist pump for coating a resist on a wafer in a semiconductor wafer exposure process or the like, and more particularly to a high viscosity resist pump using a high viscosity resist.

BACKGROUND OF THE INVENTION A resist pump is used to supply a resist onto a material to be coated. This resist pump is provided with a suction port and a discharge port in a jacket that covers an expandable bellows, and an air cylinder inside the bellows expands and contracts the bellows to suck and discharge the resist into the space between the bellows periphery and the inside of the jacket. Is. The bellows of such a resist pump is Teflon (trade name: American EIdu
(Pont de Nemous & Co. Inc.) and other polyfluorinated ethylene fibers.

[Prior Art] In a conventional resist pump, particularly when a highly viscous resist is used, the resistance inside the jacket increases and the resist discharge pressure becomes very large, and a large pressure is applied to the bellows surface, causing the bellows to undergo plastic deformation. In some cases, this may occur or cause damage or the like, resulting in defective suction or discharge.

[Object of the Invention] The present invention has been made in view of the above-mentioned drawbacks of the prior art, and reduces damage and deterioration of the bellows due to pressure on the bellows when using a high-viscosity resist, and highly reliable resist suction and discharge. An object is to provide a high-viscosity resist pump that achieves operation.

[Embodiment] FIG. 1 shows the configuration of an embodiment of the high clay resist pump according to the present invention. Inlet 8 and outlet 9 of jacket 3
A suction pipe 10 and a discharge pipe 11 are connected to the respective via check valves 1a and 1b. Teflon (Product name:
A bellows 2 made of polyfluorinated ethylene fiber such as EI du Pont de Nemous & Co. Inc. in the United States is arranged. An air cylinder 4 is provided inside the bellows 2, and the rod 4a is moved up and down to expand / contract the bellows 2 by raising and lowering air pressure to the air cylinder. An air pipe 12 is further connected to the jacket 3 via a pressure control device 5. The pressure control device 5 is composed of a variable throttle valve 6 and a check valve 7. This air pipe 12 is connected to the same air pump 20 as the air cylinder 4. Air pump is air pipe 12
The air cylinder 4 and the air cylinder 4 may be provided separately.

Next, the operation of the resist pump having the above structure will be described. When the air supply pressure from the air pump 20 is lowered and the air cylinder 4 is driven downward, the rose 2 contracts accordingly and moves downward, and the resist passes through the suction port 8 and the resist blows the bellows 2.
The space between the outside of the and the inside of the jacket 3 is sucked and filled. Next, when the air supply pressure is increased and the air cylinder 4 is driven upward, the bellows 2 expands and moves upward accordingly, and the resist in the jacket 3 is discharged through the discharge port 9. At this time, the pressure control device 5 is passed through the air pipe 12.
Compressed air is supplied to the jacket 3 via. The compressed air is introduced into the bellows 2 and pressure control is performed by the pressure control device 5 so as to maintain a balance with the resist pressure around the outside of the bellows 2. By introducing a pressure against the discharge pressure at the time of discharging the resist into the bellows 2 in this manner, the pressure inside and outside the bellows is balanced and the plastic deformation and damage of the bellows due to the discharge pressure applied to the outer surface of the bellows are prevented. To be prevented.

[Effects of the Invention] As described above, the resist pump according to the present invention includes the pressurizing means for pressurizing the inside of the bellows in response to the resist pressure around the bellows.
Even when a high-viscosity resist is used, the bellows are prevented from being plastically deformed, destroyed, or deteriorated due to the resist discharge pressure, the durability of the bellows is improved, and highly reliable resist suction and discharge operations are achieved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a high viscosity resist pump according to the present invention. 1a, 1b, 7: Check valve, 2: Bellows, 3: Jacket, 4: Air cylinder. 5: Pressure control device.

Claims (4)

[Claims] 1. A container having a resist inlet and outlet, a bellows provided in the container, driving means provided inside the bellows for expanding and contracting the bellows, and resist pressure around the bellows. And a pressurizing device for pressurizing the inside of the bellows. 2. The high-viscosity resist pump according to claim 1, wherein the pressurizing means is compressed air introduced through a pressure control device including a check valve with a variable throttle valve. 3. The high-viscosity resist pump according to claim 1 or 2, wherein the driving means is an air cylinder operated by air pressure. 4. The high-viscosity resist pump according to any one of claims 1 to 3, wherein the bellows is made of polyfluorinated ethylene fiber.