JP2001155985A - Filter apparatus and resist coating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To feed a constant volume of chemical liquid by completely excluding air bubbles in a filter apparatus, in which a constant volume of chemical liquid is introduced, filtered, and fed to other apparatus. SOLUTION: A valve disc 7, that closes a discharge opening for discharging chemical liquid containing air bubbles and remains in the filter apparatus, is provided. A valve seat 9 of the discharge opening is closed after the remaining chemical liquid with air bubbles is pushed out to the outside through the discharge pipe 5 in advance, and the chemical liquid in the housing 2 free of compressive air bubbles is sent out at a constant pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter for supplying a chemical solution from one direction, filtering the chemical solution and discharging the chemical solution in the other direction, and applying the chemical solution to a semiconductor substrate (hereinafter simply referred to as a wafer) using a resist solution. The present invention relates to a resist coating device that applies a resist liquid.

[0002]

2. Description of the Related Art In a resist coating apparatus, which is a type of chemical liquid coating apparatus, the discharge amount of a resist liquid, which is a chemical liquid discharged from a nozzle, is an important parameter in quality. If the resist solution discharge amount is small, there arises a problem that a resist film having a predetermined thickness is not formed on the silicon substrate.
Therefore, a system that can obtain a stable discharge amount of the chemical solution is required.

Further, from the viewpoint of cost reduction, it is necessary to minimize the amount of the resist solution used. Therefore, by obtaining a stable discharge amount, the margin per discharge amount can be reduced. It is necessary to reduce the discharge amount itself and the amount of the discharged resist liquid.

Although various methods for reducing the amount of the resist solution have been proposed as described above, on the other hand, there is a problem of deposition of foreign matter due to bubbles which cause defects in the quality of the resist film. The cause of the bubble generation is caused by leaks in the piping of the resist supply system and the piping joints of the filter device. In particular, the air bubbles generated in the filter housing reach the upper part, grow into large air bubbles, and deposit foreign matter. This foreign matter causes a defect in the resist film or causes a shortage of the resist solution to the nozzle.

[0005] A filter device that solves the problem of air bubbles is disclosed in Japanese Patent Application Laid-Open No. 5-228304.
FIG. 4 is a sectional view showing a filter device disclosed in Japanese Patent Laid-Open No. 5-228304.

[0006] As shown in FIG.
A filter container 20 having a filter inlet 21 for introducing the resist solution pumped from the pump and a filter outlet 24 for discharging the resist solution, and a filter portion 23 built in the filter container 20 and fixed by a retainer 26 are provided. .

The operation of this filter device is as follows. First, the pressurized resist solution is supplied from the filter inlet 21 to the filter container 2.
0, passes through the filter unit 23, is discharged from the filter outlet, and is supplied to another device.

At this time, the bubbles generated on the inner wall of the filter container 20 and the surface portion of the filter portion 23 by the vibration of the vibration device 25 are separated. The peeled air bubbles form the filter container 2
When the inside of the container is pressurized, it is discharged through a discharge hole 27 and a check valve 28 together with a small amount of resist liquid when the inside of the container is pressurized.

As described above, the resist solution is vibrated to remove bubbles adhering to the walls and the filter portion, and the resist solution containing bubbles is discharged from the discharge hole 27 of the check valve 28 provided at the upper part of the container. Air bubbles were removed by discharging.

[0010]

In the above-mentioned conventional filter device, there is a disadvantage that, even if a small amount is discharged, the resist solution is discharged and consumed together with the bubbles every time the bubbles are discharged. Further, there is a problem that the bubbles contained in the remaining resist liquid are not constant, the pressure transmission of the pump changes, and the discharge amount becomes unstable. That is,
Although the bubbles discharged from the check valve do not flow back into the container, the pressure applied to the resist solution is transmitted to the bubbles that cannot be released during the discharging operation, and the remaining bubbles are compressed and the pressure is applied to the resist solution. There is a possibility that the discharge amount of the resist solution may fluctuate due to insufficient transmission.

In addition, a vibrating device must be installed in order to remove bubbles from the wall and raise the bubbles, which has the disadvantage that the device becomes large-sized. In addition, frequent vibrations from the vibration device cause the pipe joint to be loosened and the resist liquid to leak, or air to enter through the gap between the pipe joints to generate air bubbles in the pipe, preventing the resist liquid from being supplied. Contains the problem.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a filter device capable of more completely eliminating bubbles and supplying a fixed amount of a chemical solution, and a resist coating device capable of stabilizing the discharge amount of a resist solution as a chemical solution and further saving. To provide.

[0013]

A first feature of the present invention is as follows.
It has a chemical solution inlet through which a chemical solution supplied from a constant-volume discharge pump is introduced, and has a built-in filter unit for filtering the introduced chemical solution, and an outlet through which a part of the introduced chemical solution is discharged, and is filtered. A filter device comprising: a housing having a supply port for discharging the chemical solution; and an on-off valve having a valve element for closing and opening the discharge port. Further, it is preferable that a spring member that presses the valve body and closes the discharge port is provided. Further, it is desirable to provide an electromagnetic member for separating the valve body from the outlet, or to provide a pneumatic member.

According to a second feature of the present invention, there is provided a resist coating apparatus for forming a resist film on the semiconductor substrate by dropping the resist solution from a nozzle onto a rotating semiconductor substrate. A resist, comprising: a constant volume discharge pump that sucks the resist solution from the resist solution storage tank and pumps the resist solution to the inlet of the filter device according to the first feature; and a nozzle pipe that connects the supply port of the filter device and the nozzle. It is a coating device. Further, it is preferable that a moving mechanism for moving the nozzle to a position where the nozzle on the semiconductor substrate is separated from the semiconductor substrate is provided.

[0015]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing a filter device according to an embodiment of the present invention. As shown in FIG. 1, this filter device is connected to an introduction pipe 4 connected to an introduction port for introducing a chemical solution supplied from a fixed-rate discharge pump, and to a supply port for filtering the introduced chemical solution and supplying it to another device. Supply pipe 3
And an on-off valve 1 for closing or opening a discharge port connected to a discharge pipe 5 for discharging a chemical solution containing air bubbles remaining in the housing 2.

FIGS. 2A and 2B are cross-sectional views for explaining the operation of the filter device shown in FIG. Hereinafter, the chemical solution will be described as a resist solution. When the resist liquid is supplied from the supply pipe 3 to another portion, the filter liquid is supplied by a constant discharge pump with the valve disc 9 closed with the valve seat 9 as shown in FIG. Is fed through the filter section 6 from the introduction pipe 4 to the supply pipe 3
To other parts.

At the beginning of use, the housing 2
If you want to remove the air bubbles inside, as shown in FIG.
Even when the valve disk 7 is retracted, the opening of the valve seat 9 is opened, and a part of the resist solution fed from the introduction pipe 4 flows into the discharge pipe 5 through the opening of the valve seat 9 and is discharged together with the bubbles.

It is desirable to use air pressure or electromagnetic force to retract the valve disk 8. In any case, the force for closing the valve seat 9 is based on the repulsive force of the spring 8. It is desirable to set the repulsion at least twice the discharge pressure of the pump. Then, even if an operation signal to the air switching operation valve or the solenoid valve is not transmitted due to a failure or some other accident, the valve disc 7 closes the valve seat 9 by a spring, and the resist solution containing bubbles does not flow back into the housing 2. It has become.

When the discharging operation is performed with the opening / closing valve 1 closed as described above, the entire resist liquid flowing from the introduction pipe 4 is filtered by the filter unit 6 and supplied to other parts. Therefore, the resist solution is supplied in a stable amount without waste.

Further, the resist liquid containing bubbles and remaining in the discharge pipe 5 is isolated from the inside of the housing 2 by the valve disk 7, so that even if the inside of the housing 2 becomes a negative pressure, it does not flow backward. Furthermore, when the resist liquid in the housing 2 is discharged, even if it is pressurized, there is no bubble, so that the liquid pressure is constant and the discharge amount does not fluctuate.

FIG. 3 is a piping diagram schematically showing a resist coating apparatus according to an embodiment of the present invention. As shown in FIG. 3, the resist coating apparatus includes a spin chuck 1
The nozzle 11 for dropping the resist solution onto the wafer 29 held by the nozzle 3, the chemical solution tank 16 for storing the resist solution, the resist solution is sucked from the chemical solution tank 16, and the resist solution is sent to the filter device 10 via the supply pipe 18. A pump 15 for pumping;
The resist solution filtered by the filter device 10 is passed through the nozzle 11
And a nozzle pipe 17 for sending liquid to the nozzle.

In order to move the nozzle 11, it is desirable to provide, for example, a rotary actuator which turns the nozzle pipe 17 around the swivel joint 12. On the other hand, a control unit 19 for controlling a power supply for driving the pump 15, an opening / closing valve for venting the trap tank 14, an opening / closing valve (not shown) provided in the middle of the nozzle pipe, and the opening / closing valve 1 directly connected to the filter device 10. Is also provided. Note that the filter device 10 is the filter device of FIG.
The pump is a bellows pump.

Next, the operation of the resist coating apparatus will be described with reference to FIGS. First, the pump 15 of FIG.
The resist solution is sucked from the chemical solution tank 16 by one operation of FIG.
To the introduction pipe 4. At this time, the filter device 10
Open / close valve 1 is open. Fig. 2
It is supplied to the nozzle 11 via the nozzle pipe 17 after passing through the filter part 6 of (b). At this time, the resist solution is dropped from the nozzle 11 of B located outside the wafer 29 by the swivel joint 12. In addition, as shown in FIG. 2B, the state of the filter device at this time is such that a part of the resist solution that has been fed under pressure is discharged from the opening of the valve seat 9 to the discharge pipe 5 together with bubbles. With this operation, the bubble removing operation in the preparation operation is completed.

Next, the operation of forming a resist film will be described. First, FIG. 2 of the filter device 10 from which air bubbles have been completely removed.
The opening of the valve seat 9 is closed with the valve disc 7 of FIG. This is performed by the control unit 19 shown in FIG. Next, the nozzle pipe 17 is pivoted around the swivel joint 12.
Turns, and the nozzle 11 is positioned at the position A above the wafer 29. Then, a pump is operated in response to a signal from the control unit 19, and the resist solution is pumped to the filter device 10.

As shown in FIG. 2 (a), the resist solution fed under pressure enters the inlet tube 4 and is filtered by the filter unit 6 and sent from the supply tube. Then, the resist solution is dropped from the nozzle 13 onto the wafer 29 via the nozzle pipe 17. Then, the wafer 29 is rotated by the rotation of the spin chuck 13, and the dropped resist liquid is extended outward to form a resist film. Next, the wafer 29 on which the resist film is formed is removed, the unprocessed wafer is held by the spin chuck 13, and the same operation as described above is repeated. A resist film is formed on the wafer 29. As described above, it is desirable to perform the bubble removing operation after performing the coating operation on one lot of wafers.

By using this filter device, the resist coating device only needs to consume the resist solution used in one or two bubble removal operations, and most of the remaining resist solution is used for forming the resist film. Therefore, it is possible to save about half as compared with the conventional resist coating apparatus in which the resist liquid is discharged together with the bubbles by the check valve every time the resist liquid is supplied to the nozzle.

[0028]

As described above, according to the present invention, a valve element is provided for closing a discharge port for discharging a chemical solution containing air bubbles remaining in a filter device. The outlet can be closed and the chemical in the housing without bubbles with compressibility can be pumped at a constant pressure, so the discharge rate of the chemical from the supply port is always stable, and the quality of the applied liquid is kept constant. This has the effect.

Further, by providing the above-described filter device in a resist coating device using a resist solution as a chemical solution, a stable discharge amount of the resist solution can be dropped onto the wafer, so that a uniform resist film can be formed on the wafer. is there. Moreover, since bubbles can be removed by one or two discharge operations, the use efficiency of the resist solution is also improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a filter device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining the operation of the filter device in FIG.

FIG. 3 is a piping diagram schematically illustrating a resist coating apparatus according to an embodiment of the present invention.

FIG. 4 is a sectional view showing a filter device disclosed in Japanese Patent Application Laid-Open No. 5-228304.

[Explanation of symbols]

 Reference Signs List 1 opening / closing valve 2 housing 3 supply pipe 4 introduction pipe 5 discharge pipe 6 filter section 7 valve disk 8 spring 9 valve seat 10 filter device 11 nozzle 12 swivel joint 13 spin chuck 15 pump 16 chemical solution tank 17 nozzle pipe 18 supply pipe 19 control Part 29 Wafer

Claims (6)

[Claims] An exhaust system having a chemical solution inlet for introducing a chemical solution supplied from a constant volume discharge pump, a filter unit for filtering the introduced chemical solution, and discharging a part of the introduced chemical solution. A filter device, comprising: a housing having an outlet and a supply port for discharging the filtered chemical solution; and an on-off valve having a valve element for closing and opening the discharge port. 2. The filter device according to claim 1, further comprising a spring member that presses the valve body and closes the discharge port. 3. The apparatus according to claim 1, further comprising an electromagnetic member for separating the valve body from the discharge port.
The filter device according to any one of the preceding claims. 4. The apparatus according to claim 1, further comprising a pneumatic member that separates the valve body from the discharge port.
The filter device according to any one of the preceding claims. 5. A resist coating apparatus for forming a resist film on a semiconductor substrate, wherein the chemical liquid according to claim 1 is a resist liquid, wherein the resist liquid is dropped from a nozzle onto a rotating semiconductor substrate. 2. A resist coating apparatus, comprising: a constant volume discharge pump for pumping the resist solution to the inlet of the filter device according to claim 1; and a nozzle pipe connecting a supply port of the filter device and the nozzle. . 6. The resist coating apparatus according to claim 5, further comprising a moving mechanism for moving the nozzle on the semiconductor substrate to a position outside the semiconductor substrate.