JPH0760786B2 - Resist coating device - Google Patents

Description

The present invention relates to a resist coating apparatus, and more particularly to a resist coating apparatus having a dummy dispensing function.

(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).

(Problems to be Solved by the Invention) According to the above-described conventional apparatus, if the resist coating operation is not performed for a long time in a state where the resist solution is delivered to the tip of the resist nozzle and can be dropped, air will be generated at the tip of the resist nozzle. Since the resist solution that comes into contact with it solidifies or the components of the resist solution change and deteriorate, if this is used as it is in the next coating operation, proper resist coating cannot be performed.

In such a case, it is preferable to discard the deteriorated resist liquid and execute the coating operation using the resist liquid without deterioration. In this way, the operation of discarding the deteriorated resist liquid is referred to as dummy dispensing, and the resist liquid is discharged and discarded to a place other than the chuck for chucking the wafer.

Here, in the conventional apparatus, when performing the dummy dispensing of the resist solution, it was performed manually, so that the work was extremely complicated. In particular, 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 a manual dummy described above. Needs dispensing work.

Here, the resist liquid has various timings for executing the dummy dispense depending on the difference in the manufacturer of the resist liquid or the user who uses the coating apparatus, and when performing the manual dispense, also manage the dummy dispense. However, 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 automatically execute the dummy dispensing work of the resist solution when the resist solution may deteriorate. It is an object of the present invention to provide a resist coating apparatus which can be greatly simplified.

[Structure of the Invention] (Means for Solving the Problems) In the resist coating apparatus that performs resist coating by dropping the resist solution on the surface of the material to be coated by the resist solution discharging means, In this state, when the liquid is not dropped for a set time or longer, a means is provided for automatically executing the dummy dispensing operation by the resist solution discharging means at least once.

Then, when the dropping is not performed for the set time or longer, it can be determined by, for example, detecting that the coating member before the coating step is not present at the predetermined position for the set time or longer.

In this case, the lot break time is long, and if the dummy dispense is executed every time the set time elapses during this period, the resist solution is wasted so much that the lot break is confirmed as a ready state. Alternatively, the dummy dispense may be executed only once immediately before the next coating operation is started.

(Operation) The dummy dispense of the deteriorated resist solution is necessary, for example, when the material to be coated is not carried into the coating apparatus and the dispense cannot be performed for a long time. Therefore, in the present invention, when the dropping is not performed for a predetermined time even in the drip enable state, for example, when the material to be coated before the coating step is not present at the predetermined position for a set time or more, Since the dummy dispensing operation is performed at least once, the proper dummy dispensing operation can be surely performed, and the burden on the operator can be significantly reduced.

Here, if it is configured to be executed only once immediately before the next coating operation is started, the expensive resist liquid is consumed even if the material to be coated is not set in the predetermined position for a long time. Waste can be reduced as much as possible.

(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 pointed to by the chuck 10, there is provided a resist nozzle 30 for dropping a resist solution from a substantially central position of the wafer 1, and the resist nozzle 30 is movable by a scanner 31. For example, if the dispense from the nozzle 30 is not performed for a predetermined time due to a lot break or the like, the resist solution may harden due to the contact with the air at the tip of the nozzle for a long time. Since it is necessary to retreat the nozzle 30 to a position removed from the chuck 10 in this case, this kind of movement is executed by the scanner 31. In addition,
In this embodiment, as will be described later, this type of resist nozzle 30
A plurality of them are provided and used 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 second 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 wafer 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.

The filter container 34 is for removing dusts and the like by a mesh filter, and the filter container 34 has an air discharge pipe 60 connected to the upper end thereof.
Air trapped inside when trapped inside can be discharged through the air discharge pipe 60 by driving the valve 36 and a vacuum pump (not shown).

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

The CPU 70 controls the control of the apparatus of this embodiment, and in particular, can control the drive of the bellows pump 33 in order to control the dummy dispensing operation described above. As described above, this embodiment has a plurality of systems, for example, three systems of resist supply systems, and the CPU 70
Can drive and control the first to third bellows pumps 33-1, 33-2, 33-3, respectively. In addition, when performing dummy dispense, the registration nozzle 30
It is necessary to retreat from the upper area of the chuck 10 for execution, so that it becomes possible to drive and control the first to third scanners 31-1, 31-2, 31-3 arranged for each supply system. ing. Therefore, the resist nozzles 30-1, 30-2, 30-3 can be independently centered on the chuck 10 and can be retracted.

Further, the CPU 70 may deteriorate the resist liquid at the tip of the nozzle 30 due to the fact that the dispensing is not performed for a predetermined time. Therefore, after this time has elapsed, the time for starting the dummy dispensing operation is set. A time setting unit 71 is connected, and in this embodiment, for example, 1 second to 99 seconds.
It is possible to set any time within 9 seconds. Also,
Before the wafer 1 is loaded into the coating apparatus, the CPU 70 is supplied with a transport ready signal which is output when the wafer 1 is present in the transport section at the previous stage.

Then, the CPU 70 connects the counter 72 that counts down the set time after the conveyance ready signal is cut off, and resets the counter 72 when the next conveyance ready signal is received before the set time elapses, and then the next conveyance is performed. If the set time has elapsed before the ready signal is received, the pump 33-
1-33-3 and scanners 31-1 to 31-3 are drive-controlled to execute and control the dummy dispensing 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
A predetermined amount of resist solution is dropped onto the surface of the wafer 1 from 30. 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 wafer 1 contaminated by the above operation is started. This back surface cleaning is performed while discharging a cleaning agent such as a solvent from the cleaning nozzle 50 and rotating the wafer 1 by the motor 20 at a rotation speed of about 2000 rpm, for example.

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.

Through the above operation, one cycle of the resist coating operation for one wafer 1 is completed, and thereafter, this cycle is repeatedly executed each time the transport ready signal is received.

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 there is a deteriorated resist solution at the tip of the resist nozzle 30, the proper ejection operation cannot be ensured. Such deterioration is caused by the resist nozzle 30.
If dispensing is not performed for a longer period of time, the nozzle
30 It is caused by the contact of the resist liquid at the tip with the air.

Therefore, the CPU 70 automatically controls the execution of the dummy dispense operation of the deteriorated resist solution.

That is, the time setting unit 71 sets in advance the time after which the dummy dispense operation is started after the transport ready signal is interrupted. Then, after the conveyance ready signal is cut off, the counter 72 counts down this set time. The output of the counter 72 allows the CPU 70 to detect that the set time has elapsed. When the next ready signal is input before the set time has elapsed, the counter 72 is reset.

This dummy dispense operation is executed as follows. That is, the scanner 3 is first controlled by the CPU 70.
1 is driven to scan the resist nozzle 30 at a position facing the center of the chuck 10 to a position outside the chuck 10, and then the bellows pump 33 is driven to cause a predetermined amount of resist from the tip of the nozzle 30. It is performed by dispensing the liquid.

Here, in the present embodiment, the following four types of modes can be selected in order to control execution of dummy dispensing in a plurality of resist supply systems.

<First Mode> In this mode, any one of the three resist supply systems is designated, and the dummy dispense is executed only for the designated resist supply system at the set time. is there.

<Second Mode> This mode is a mode in which dummy dispense is simultaneously executed for the first resist supply system and the second resist supply system.

<Third Mode> In the above first and second modes, there is a risk that dummy dispense will be executed for systems other than the resist supply system currently in use. The third mode is a mode in which the dummy dispense is executed only for the resist supply system. According to the third mode, even when the resist supply system is changed, the dummy dispense currently in use can be reliably executed without changing the mode.

<Fourth Mode> This fourth mode is a further advance of the third mode. According to the third mode, for example, if the preset time elapses between lot breaks, the dummy mode can be repeated any number of times. Dispense will be executed, but in this fourth mode,
Even when the set time has elapsed, the dummy dispense ready state is maintained, and the dummy dispense is executed only once when the next transport ready signal is input. The reason for doing this is that the resist solution is expensive, so if it is executed many times, the resist solution will be wasted and the next coating after the wafer coating operation is interrupted, as in the case where the next lot is started. The dummy dispense is executed only once immediately before the operation is started, so that the waste of the resist liquid is eliminated and the deteriorated resist liquid is surely discarded.

As described above, according to the above-described embodiment, it is possible to automatically execute the dummy dispensing operation by selecting any one of the above modes and executing the dummy dispensing.
Once the set time is set, it is not necessary to manage the schedule of the dummy dispense, so the management burden on the operator is also reduced and the proper execution of the resist dispensing operation is always ensured by reliably preventing the non-execution of the dummy dispense process can do.

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.

For example, when performing a dummy dispense, it is necessary to prevent the resist liquid from being applied onto the chuck, but the structure is not limited to the one that retracts the resist nozzle 30 as in the above-described embodiment, but the configuration becomes slightly complicated. It is also possible to adopt a configuration in which the tray for the waste resist solution is moved to the tip of the resist nozzle 30. Further, various members constituting the coating apparatus are not limited to those described 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, when the dropping is not performed for a set time or longer while the dropping is possible, the dummy dispensing operation of the deteriorated resist solution is automatically performed at least once. Since it can be performed, the work is greatly simplified compared to the conventional manual work,
Moreover, since it is not necessary to manage the operation of the dummy dispense after setting the time once, and the dummy dispense operation is surely executed at the timing when the resist solution may deteriorate, it is possible to always ensure the uniform coating of the resist. it can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a control system for a dummy dispensing operation in an apparatus in which the present invention is applied to a semiconductor wafer resist coating apparatus, and FIG. 2 is the resist of FIG. It is a schematic explanatory drawing for demonstrating the whole structure of a coating device. 1 ... coated material, 30 ... resist nozzle, 33 ... bellows pump, 70, 71, 72 ... control means.

Claims (3)

[Claims] 1. In a resist coating apparatus for performing resist coating by dropping a resist solution onto the surface of a material to be coated by a resist solution discharge means, when the resist droplet cannot be dropped for a set time or longer in the state where the resist droplet can be dropped. A resist coating apparatus, which is provided with a control unit that automatically controls execution of a dummy dispensing operation by the resist liquid discharging unit at least once. 2. The resist liquid discharging means according to claim 1, wherein the plurality of resist liquid discharging means are controlled by the control means, and the control means controls execution of the dummy dispensing operation for the resist liquid discharging means currently in use. A resist coating apparatus characterized in that. 3. The control means according to claim 2, wherein the control means waits for the presence of the material to be coated to be confirmed before the resist coating area, in the case where the material is not dropped for the set time or longer. A resist coating apparatus, which controls execution of the dummy dispensing operation at least once.