JPH0750673B2 - Resist coating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) [0001] The present invention relates to a resist coating apparatus, and more particularly to an improvement of an apparatus for venting air while supplying a resist solution.

(Prior Art) An example of this type of coating apparatus is a coating apparatus that coats a resist on a wafer in a semiconductor manufacturing apparatus. When applying a resist on a wafer, the wafer is placed and fixed on a rotatable spin head placed inside the processing container, and while rotating the wafer, the resist solution is supplied to the wafer surface through a nozzle to apply the resist. It is being processed (Japanese Patent Publication No. 53-37189).

Here, if air is mixed in the middle of the resist supply path, the resist is dried and its components are changed, or if air is mixed between the resist discharge pump and the nozzle, the amount of liquid dropped is Since it changes and uneven coating of the resist occurs, it is necessary to remove it in the middle of the resist supply path.

Therefore, during the supply of the resist solution to the nozzle, the fourth
As shown in the figure, a trap 101 accommodating a filter 100 for removing dust is provided inside, air is stored in the upper part of this trap 101, and this is removed via a discharge pipe 102.

When the air is removed from the trap 101 in the conventional device, the exhaust pipe 102 is evacuated by a vacuum pump. Driving the vacuum pump and opening / closing the valve 103 provided in the exhaust pipe 102. Was done manually.

(Problems to be Solved by the Invention) According to the above-described conventional apparatus, when the air is removed from the resist supply path, it is performed manually, so the work is extremely complicated. Particularly, in this type of resist coating apparatus, there are some types that use about three types of resist liquids, and in this case, each has a resist supply system, and therefore each of the resist supply systems has the above-mentioned manual air venting operation. Need work.

There are various types of resist solutions, such as one that is performed once a day, one that is performed once every three days, and one that is performed once a week, due to differences in the air bleeding frequency due to differences in manufacturers, etc. When it is carried out, it is necessary to carry out the management of the air bleeding schedule, etc., and if this is forgotten, there is a problem that the resist coating operation is hindered.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and to perform air venting work in the middle of the resist supply path automatically at appropriate intervals according to the type of resist liquid. An object of the present invention is to provide a resist coating apparatus that can greatly simplify the work.

[Structure of the Invention] (Means for Solving Problems) The present invention relates to a coating apparatus for dripping and applying a resist solution onto the surface of a material to be coated. And an air discharging means for sucking and discharging the air accumulated in the upper part of the trap container, and an air discharging means for driving the air discharging means every time a preset time has elapsed in accordance with the type of the resist liquid. The control means for automatic control is provided.

Here, it is preferable that when the set time has elapsed, the air bleeding ready state is set, and the process is performed after confirming a break or the like of the lot in which the material to be coated carried into the coating device does not exist at a predetermined position.

Further, it is preferable that the trap container is arranged at a rear stage side of a pump for driving the discharge of the resist liquid, and the trap container may also serve as a filter container.

(Operation) In the present invention, when the air accumulated in the upper part of the trap container is discharged by driving the discharging means, the interval time for repeating the air bleeding every predetermined time is set in advance according to the type of the resist liquid, Since the air bleeding operation is automatically performed every time this time elapses, it is possible to reliably carry out the appropriate air bleeding work according to the type of resist liquid, and to significantly reduce the burden on the operator. You can

Here, the air bleeding operation needs to be performed when the resist coating operation is not executed, and it is inefficient to interrupt the coating operation in the middle of the lot, so once the set time has passed, the ready state is temporarily set, It can be dealt with by checking after checking the lot breaks.

In addition, since air is often mixed in the resist solution when the pump for driving the resist solution is driven, it is preferable to dispose such air by arranging the trap container on the downstream side of the pump.

(Example) Hereinafter, one example in which the present invention is applied to a resist coating apparatus for a semiconductor wafer will be specifically described with reference to the drawings.

First, the outline of the resist coating device will be described.

The spin chuck 10 is one that can mount and fix the semiconductor wafer 1 by vacuum suction and rotate the semiconductor wafer 1,
The spin chuck 10 is fixed to the output shaft of a motor 20 and is rotationally driven. The motor 20 is composed of a high-performance motor having an excellent accelerating property, has a flange 21 on its upper side, and is fixed at an appropriate position in the coating apparatus by this flange 21. The flange 21 can be temperature-controlled by a temperature controller (not shown), and may be configured not to transmit heat generated by the motor 20 to the upper side.

Above the wafer 1 supported by the chuck 10, a resist nozzle 30 for dropping a resist solution from a substantially central position of the wafer 1 is provided, and the resist nozzle 30 is movable by a scanner 31. For example, if the dispense from the nozzle 30 is not executed for a predetermined time due to a lot break or the like, the resist solution may be hardened by contact with air at the tip of the nozzle 30 for a long time, so it is necessary to execute the dummy dispense. In this case, since it is necessary to retract the nozzle 30 to the position where it is removed from the chuck 10, this type of movement can be performed with the scanner.
It is designed to be run by 31. It is also possible to provide a plurality of resist nozzles 30 of this type and to use them properly according to the type of resist solution.

In addition, in order to prevent the resist solution from splashing outside the apparatus when applying the resist solution, a cup 40 as a processing container is used.
Are formed around the wafer 1. In addition, this cup
40 is movable up and down, and is the first when the resist solution is applied.
It is configured to be raised to the position shown in the figure and stopped, and to be lowered from the above position when the wafer 1 is loaded and unloaded. A drain pipe and an exhaust pipe (not shown) are connected to the lower surface of the cup 40.

Further, a cleaning nozzle 50 for cleaning the back surface of the wafer 1
Is fixed to a flange 21 for mounting the motor 20, which is arranged at a position facing the back surface of the wear 1. The cleaning nozzle 50 needs to be fixed at least at a position off the chuck 10. The cleaning nozzle 50 is provided with a solvent containing portion 51 for supplying a cleaning liquid such as a solvent, and the solvent can be discharged to the back surface of the wafer 1 through the cleaning nozzle 50.

Next, a system for supplying the resist liquid to the resist nozzle 30 will be described. As the supply system, a resist liquid storage unit 32, a bellows pump 33, a filter container 34 which is an example of a trap container, and a valve V1, a suck back valve V2, etc. which are opened and closed in conjunction with the bellows pump 33 are provided. There is. The suck back valve V2 is a valve for drawing back the resist solution exposed by surface tension at the tip of the resist nozzle 30 into the resist nozzle 30 after the resist solution is discharged from the resist nozzle 30. This is to prevent solidification.

The bellows pump 33 is composed of a cylinder 33a, a check valve 33b and a bellows portion 33c, a resist solution introducing pipe is connected between the check valve 33b and the cylinder 33a, and the resist solution is fed from the upper end of the bellows section 33c. Can be derived. The cylinder 33a includes a port 33 for introducing air above and below the partition plate 33d.
e and 33f are provided, and the pump operation can be executed by moving the partition plate 33d up and down.

Next, a structure for removing air from the resist solution from the filter container 34 will be described with reference to FIG.

The filter container 34 has a shape in which the upper wall connecting the resist liquid introducing pipe 34a is inclined so that the side to which the resist liquid introducing pipe 34a is connected is arranged on the lower side and the side to which the air discharging pipe 60 is connected is arranged on the upper side. , Place the filter 34b inside it,
The resist liquid that has passed through the filter 34b can be discharged from the lower end.

An air vent valve 61 that can be opened and closed by, for example, solenoid drive is provided in the middle of the discharge pipe 60, and a waste liquid trap 62 is provided at the subsequent stage side. At the lower end of the waste liquid trap 62, a waste liquid valve 63 that is similarly opened and closed by solenoid drive or the like is provided, while at the upper end of the waste liquid trap 62, a vacuum pipe 64 is connected, and air removal can be performed by a vacuum pump 65. ing.

Next, a control system for controlling the air venting operation will be described with reference to FIG.

The CPU 70 controls the control of the apparatus of this embodiment, and in particular, in order to control the air venting operation described above, it is possible to perform opening / closing drive control of the air vent valve 61 and the waste liquid valve 63 and drive control of the vacuum pump 65. Has become. Also this
The CPU 70 is connected to a time setting unit 71 for setting an interval time for repeating the air bleeding operation at predetermined time intervals according to the type of resist liquid. When there are a plurality of resist supply systems, each supply system is connected. It is possible to set the time. In addition, the CPU 70 has a wafer 1 attached to this coating device.
Before carrying in the wafer, a carry-in ready signal that is output when the wafer 1 is present in the preceding transfer section is input.

Then, the CPU 70 is connected to a counter 72 that counts down the set time after the completion of the air bleeding operation, and is in the air bleed ready state after the lapse of the set time, and a transfer ready signal is not input, for example, at a lot break or the like. After confirmation, the valves 61 and 63 and the vacuum pump 65 are driven to execute and control the air venting operation. In this sense, the CPU 70, the time setting unit 71, and the counter 72 are examples of the control means of the present invention.

Next, the operation will be described.

First, in a normal resist coating process, after the CPU 70 receives a transfer ready signal from the transfer unit, it detects that the wafer 1 does not already exist on the chuck 10 by a vacuum check of the chuck 10 and confirms the absence of the wafer 1. Once done,
The wafer 1 is loaded into the coating apparatus and placed on the chuck 10.

Next, the vacuum system of the spin chuck 10 is driven to fix the wafer 1 on the spin chuck 10 by vacuum suction.

Then, the cup 40 is raised and stopped at the position shown in FIG.

The above-described transfer driving is executed based on a command from the CPU 70 of the resist coating apparatus, according to a transfer program installed in advance. After the end of the transport drive, the resist coating operation is started by executing an original program incorporated by the user by a recipe controller (not shown). That is, while the wafer 1 on the spin chuck 10 is rotated at about 1000 rpm by driving the motor 20, the valves V1 and V2 are opened and the bellows pump 33 is driven to move the wafer 1 above the wafer 1 located substantially at the center thereof. Registration nozzle set to position
From 33, a predetermined amount of resist solution is dropped on the surface of the wafer 1. After that, the rotation speed of the wafer 1 is increased to about 4000 rpm to rotate the wafer 1, and the resist solution is uniformly applied to the surface of the wafer 1 by the centrifugal force.

At this time, the resist solution scattered from the end of the wafer 1 is guided to the bottom by the cup 40 and discharged from a drain pipe (not shown).

After the above resist coating operation is completed, the back surface cleaning of the furnace wafer 1 contaminated by the above operation is started. In this back surface cleaning, a cleaning agent such as a solvent is discharged from the cleaning nozzle 50,
Further, the wafer 1 is executed while being rotated by the motor 20 at a rotation speed of, for example, about 2000 rpm.

After the back surface cleaning of the wafer 1 described above, the cup 40 is lowered below the position shown in FIG.
After turning off the vacuum of 10, the wafer 1 is unloaded.

By the above operation, one cycle of the resist coating operation for one wafer 1 is completed, and thereafter, this cycle is repeated.

Here, in this type of resist coating apparatus, there is a demand for uniformly coating the resist liquid on the wafer 1, and for this purpose, it is necessary to discharge an appropriate amount of resist liquid from the nozzle 30. If air is mixed in the resist supply system, the proper ejection operation cannot be ensured, and the resist liquid is dried by coming into contact with the air and its components change. There are also problems.

Therefore, the CPU 70 automatically controls the air venting operation in the resist supply system.

That is, the time setting unit 71 is set in advance according to the type of resist liquid.
The interval time for repeatedly performing the air bleeding operation is set by.

Then, the counter 72 counts down this set time. When the CPU 70 detects from the output of the counter 72 that the set time has elapsed, it sets the air bleed ready state, and then checks whether or not the transport ready signal from the transport unit is input. The air bleeding operation is controlled to start only when the transport ready signal indicates, for example, a lot break that is interrupted for a predetermined time. In this way, the reason for performing the air bleeding operation at a lot break is that the resist coating operation cannot be performed in parallel during the air bleeding operation, and the resist coating operation must be performed in the middle of the lot. This is because it is inefficient because it has to be interrupted.

This air venting operation is executed as follows. That is, the resist solution is once trapped in the filter container 34, and if air is mixed in the resist solution, the air having a low specific gravity rises and accumulates above the resist solution. Here, the upper wall of the filter container 34 is inclined as shown in FIG.
With the configuration in which 60 is connected, air can be reliably accumulated in the vicinity of the exhaust pipe 60.

Here, the CPU 70 opens the air bleeding valve 61, closes the waste liquid valve 63, and controls the driving of the vacuum pump 65 to evacuate the discharge pipe 60 and draw in the air accumulated at the top of the filter container 34. Become. On this occasion,
Since the resist solution is also drawn in, the resist solution is once stored in the waste solution trap 62. And
For example, the air bleeding operation is performed for about 5 minutes, then the air bleeding valve 61 is closed, the waste liquid valve 63 is opened, and the vacuum pump 65 is stopped to end the air bleeding operation. The liquid is guided to the drain through the valve 63 and is discharged. By closing the waste liquid valve 63 thereafter, the air venting operation is completed.

In this way, since the air bleeding operation is automatically performed in the middle of the resist supply path after the set time has elapsed, the burden on the operator is greatly reduced, and even if multiple resist solutions are used, the type of resist solution can be changed. Therefore, once the set time has been set, the air venting schedule control is not required, so the operator's management burden is reduced, and the proper venting process is reliably prevented by ensuring the proper venting process. can do.

A sensor is placed in the air reservoir to detect the amount of air,
Although it is possible to automatically control the air bleeding operation by this sensor output, if the resist liquid adheres to this type of sensor, the sensor function cannot be exerted, and it is difficult to put it into practical use in terms of reliability. If the air bleeding operation is performed by time management as in the present embodiment, the above-described adverse effects are not caused and the reliability is improved.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the gist of the present invention.

In the above-mentioned embodiment, by arranging the configuration for performing the air bleeding operation at the latter stage of the supply path than the pump 33, it is excellent in that air mixed in when the pump is driven can be eliminated, but preferably the nozzle 30 However, the location is not limited to the one in which air is evacuated in the filter container 34, and any location may be used as long as the resist solution can be trapped.

Further, the various members constituting the coating apparatus are not limited to those listed in the above embodiment, and various methods such as a type in which the spin chuck moves up and down together with the motor can be adopted.

Further, the coating apparatus to which the present invention is applied is not limited to resist coating on a semiconductor wafer, but can be applied to various coating apparatuses such as resist coating on a mask.

[Effects of the Invention] As described above, according to the present invention, it is possible to automatically perform the air venting operation in the middle of the resist supply path at each set time, so that the work is significantly more than the conventional manual work. Further, since the air bleeding operation is performed reliably without the need to manage the air bleeding operation for each resist solution after the time is once set, the uniform coating of the resist can always be ensured.

Further, if the air discharge drive is performed after it is confirmed that the material to be coated does not exist in the preceding stage of the resist coating area, the resist coating operation can be interrupted because the free time of the resist coating, which is a break between lots, can be used. Without, the throughput of the process does not decrease.

[Brief description of drawings]

FIG. 1 is a block diagram of a control system for an air bleeding operation in an embodiment of the invention in which the present invention is applied to a resist coating apparatus for semiconductor wafers, and FIG. 2 illustrates the entire structure of the resist coating apparatus of FIG. FIG. 3 is a schematic explanatory view for explaining the air venting configuration of the coating apparatus of FIG. 2, and FIG. 4 is a schematic explanatory view for explaining the air venting configuration of the conventional apparatus. It is a figure. 1 ... coated material, 30 ... resist nozzle, 33 ... bellows pump, 34 ... trap container, 60, 61, 62, 63, 64, 65 ...
… Ejection means, 70, 71, 72 …… Control means.

Claims (2)

[Claims] 1. A coating apparatus for dropping a resist solution onto the surface of a material to be coated to apply the trap solution, and a trap container disposed in the middle of the resist solution supply path to suck air trapped in the upper part of the trap container. An air discharging means for discharging, and a control means for automatically controlling the air discharging operation by driving the air discharging means each time a preset time has elapsed according to the type of resist liquid are provided. Resist coating device. 2. The control means according to claim 1, wherein the control means is after a preset time has elapsed according to the type of the resist solution and there is no material to be coated in the preceding stage of the resist coating area. In addition, the resist coating apparatus is characterized in that the air discharging means is driven and controlled.