JP2005209778A - Resist coating apparatus, photoresist coating method, and optical disk manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist coating apparatus capable of reducing dissolved gas in a photoresist liquid coated on a glass master without using a special degassing apparatus.
SOLUTION: A photoresist liquid 5 applied on a glass master 1 is stored, a resist tank 6 maintained at a predetermined reduced pressure state, and a photoresist liquid 5 applied on the glass master 1 is transferred. A resist coating apparatus 100 comprising a liquid pipe 3, an internal pressure adjusting means for adjusting the resist tank 6 to a predetermined internal pressure, and a check valve 19 provided in the middle of the liquid supply pipe 3 to prevent the backflow of the photoresist liquid 5. According to the above, it is possible to prevent the gas from being dissolved into the photoresist liquid 5 without providing a large deaeration device. As a result, after the photoresist liquid 5 is applied on the glass master 1, the dissolved gas is foamed. The defects caused by doing so are greatly reduced.
[Selection] Figure 1

Description

  The present invention relates to a resist coating apparatus and the like, and more particularly to a resist coating apparatus and the like in an optical disk master master manufacturing process.

Conventionally, substrates for optical disks such as CD and CD-R are manufactured using a metal mold having a fine pattern called a stamper. In the stamper, a conductive film is usually formed by a method such as sputtering on a master master having a fine pattern formed by developing a photoresist coated on a smoothly polished glass master with a laser beam. Filmed and prepared by peeling from the glass master after electroforming.
FIG. 3 is a diagram for explaining a method of applying a photoresist on a glass master. The resist coating apparatus 300 shown in FIG. 3 includes a resist tank 36 in which the photoresist liquid 5 is stored, a coating chamber 2 in which the photoresist liquid 5 is applied to the glass master 1 placed inside, and a resist tank. A liquid feeding pipe 33 through which the photoresist solution 5 in the coating liquid is fed to the coating chamber 2, a pump 13 for pressurizing the inside of the resist tank 36, a pressurizing nozzle 37 to which the resist tank 36 and the pump 13 are connected, Is provided.
As shown in FIG. 3, the photoresist solution 5 in the resist tank 36 is pressurized by the pump 13 through the pressurizing nozzle 37 and is sent to the solution feeding pipe 33 from the resist suction port 33 b. The photoresist liquid 5 placed in a pressurized state in the liquid feeding pipe 33 is sent into the coating chamber 2 by opening the valve 33c, and is discharged onto the glass master 1 from the coating nozzle 33a.
In such a resist coating apparatus 300, a phenomenon is observed in which the dissolved gas in the pressurized photoresist solution 5 is foamed after being applied onto the glass master 1, and as a result, it is detected as a defect in the manufactured stamper. Often done. Normally, tens of thousands of substrates are formed on an optical disc by an injection molding method using the same stamper. Therefore, when a stamper having such a defect is used, the defect is transferred to all the substrates of these optical discs. Will be.
However, in a conventional optical disk such as a CD-ROM, the defect in the stamper is not so a problem because the track pitch is somewhat large. However, due to the narrowing of the track pitch corresponding to the recent increase in capacity of optical discs and the increase in NA (numerical aperture) of the objective lens accompanying the shortening of the wavelength of the laser beam used for recording / reproducing optical information, Stamper defects are regarded as important.
A method for removing dissolved gas in the photoresist solution 5 in such a conventional resist coating apparatus has been reported (see Patent Document 1 and Patent Document 2).

JP 05-267149 A JP 08-010565 A

However, the conventional method for removing dissolved gas needs to provide a special degassing device, and there is a problem that the entire device becomes large. For example, in the method described in Patent Document 1, a degassing device including a membrane tube and a vacuum container is provided in a photoresist solution feeding path, and the dissolved gas in the photoresist solution is a photoresist solution. Is removed by being reduced in pressure by a vacuum pump or the like when passing through the deaerator. Moreover, in the method described in Patent Document 2, a deaeration tower having a vacuum pump connected via a suction line is provided, and the dissolved gas in the photoresist solution is transferred to the deaeration tower. , Removed by decompression.
The present invention has been made to solve the problems in such a resist coating apparatus.
That is, an object of the present invention is to provide a resist coating apparatus that can reduce dissolved gas in a photoresist solution coated on a glass master without using a special degassing apparatus.
Another object of the present invention is to provide a photoresist coating method in which minute bubbles and uneven coating in the resist generated by the foaming of dissolved gas are reduced.
Furthermore, another object of the present invention is to provide a method of manufacturing an optical disc having a master master preparation process in which defects of a photoresist applied on a glass master are reduced.

In order to solve this problem, in the present invention, the photoresist solution applied on the glass master is always kept in a reduced pressure state. That is, the resist coating apparatus to which the present invention is applied includes a resist tank that stores a photoresist liquid applied on a glass master and is maintained at a predetermined reduced pressure state, and a photoresist liquid that is applied on the glass master. A liquid feeding pipe to be transferred, an internal pressure adjusting means for adjusting the resist tank to a predetermined internal pressure, and a check valve provided in the middle of the liquid feeding pipe to prevent the back flow of the photoresist liquid. Is.
In the resist coating apparatus to which the present invention is applied, the photoresist solution stored in the resist tank is held in a reduced pressure state, so that the gas dissolves in the photoresist solution without providing a large degassing device. As a result, defects caused by foaming of the dissolved gas after the photoresist liquid is applied onto the glass master are greatly reduced.

In the resist coating apparatus to which the present invention is applied, the resist tank is held at a predetermined reduced pressure except when the photoresist liquid is applied on the glass master, and when the photoresist liquid is applied on the glass master. In addition, if it is characterized in that it is maintained in a predetermined pressure state, the opportunity for gas to dissolve in the photoresist solution can be greatly reduced.
The resist coating apparatus to which the present invention is applied further includes a coating chamber in which a photoresist solution is coated on the glass master at the internal pressure P1, and the resist tank is held at a predetermined internal pressure P2 lower than the internal pressure P1. With this feature, for example, it is possible to hold the entire resist coating apparatus in a predetermined pressure state and hold the inside of the resist tank in a reduced pressure state.
The internal pressure P1 is preferably atmospheric pressure.

Next, in the resist coating apparatus to which the present invention is applied, the internal pressure adjusting means of the resist tank includes a switching valve that switches a reduced pressure state or a pressurized state in the resist tank, a sensor that detects the internal pressure of the resist tank, If the resist tank is provided with a pump that depressurizes or pressurizes the resist tank according to the operation of the switching valve, the deaeration process and transfer of the photoresist liquid can be controlled.
Further, in the resist coating apparatus to which the present invention is applied, a transfer means for mechanically transferring the photoresist liquid is provided upstream of the check valve of the liquid supply pipe. It is possible to transfer the photoresist liquid while always keeping the inside of the tank in a reduced pressure state.
Furthermore, the liquid supply pipe is preferably attached to the resist tank at a position farthest from the liquid level of the photoresist solution, and the opportunity for the gas to dissolve in the photoresist solution can be further reduced.

Next, the present invention is a coating method for applying a photoresist solution on a glass master, wherein the photoresist solution is held in a predetermined reduced pressure state, and a predetermined amount of the photoresist solution held in the reduced pressure state is changed to a predetermined amount. The photo resist solution is transferred through a liquid feed pipe provided with a check valve that prevents the back flow of the photo resist solution, and a predetermined amount of the photo resist solution is coated on the glass master. It is grasped as an application method.
Furthermore, the present invention is an optical disc manufacturing method comprising a step of preparing a master disc for an optical disc in which a photoresist liquid is applied on a glass master, and the step of preparing the master master for an optical disc includes storing a photoresist solution. A depressurization step for maintaining a predetermined depressurized state, and a predetermined amount of the photoresist liquid that has been depressurized is transferred through a liquid supply pipe provided with a check valve that prevents the backflow of the photoresist liquid by the predetermined pressure. It can be grasped as a method of manufacturing an optical disc characterized by having a transfer step and a coating step of applying a predetermined amount of photoresist liquid transferred in the transfer step onto a glass master. According to the present invention, an optical disc in which defects caused by foaming of dissolved gas are greatly reduced is manufactured.

  Thus, according to the present invention, the dissolved gas in the photoresist liquid applied on the glass master is reduced without using a special degassing device.

Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment of the present invention) will be described in detail.
FIG. 1 is a diagram illustrating a resist coating apparatus to which the present embodiment is applied. FIG. 1A shows a state before the photoresist is applied, and FIG. 1B shows a state where the photoresist is applied. A resist coating apparatus 100 shown in FIG. 1 includes a resist tank 6 in which a photoresist solution 5 is stored, a coating chamber 2 in which the photoresist solution 5 is applied to a glass master 1 placed inside, and a resist tank. 6 is connected to the bottom of the resist tank 6, and the resist solution 6 in the resist tank 6 is fed to the coating chamber 2. As will be described later, the inside of the resist tank 6 is used as an internal pressure adjusting means for the resist tank 6. A pump 13 for depressurization or pressurization, a suction / pressure nozzle 8 to which the resist tank 6 and the pump 13 are connected, an exhaust valve 11 and an intake valve 12 provided in the suction / pressure nozzle 8, and the inside of the resist tank 6 And a switching valve 10 for switching the intake and exhaust of the resist tank 6 by the pump 13 in accordance with the decompression or pressurization of the pump. Resist liquid 5, a check valve 19 which opens in only one direction sent from the resist tank 6 to the coating chamber 2, is provided.
In the resist coating apparatus 100, the resist suction port 3 b of the liquid feeding pipe 3 is connected to the bottom of the resist tank 6 that is farthest from the interface of the photoresist liquid 5, and into the photoresist liquid 5 sent to the coating chamber 2. It has a structure in which gas is difficult to dissolve. In addition, a buffer portion 14 having a taper angle of 1/1 or less and having the flow path of the liquid supply pipe 3 gently expanded is provided in the middle of the liquid supply pipe 3. Further, a pressure sensor 15 for detecting the pressure in the resist tank 6 is attached to the upper part of the resist tank 6, and the pressure sensor 15 and the pump 13 are connected by a line 16.

Next, the operation of the resist coating apparatus 100 will be described. As shown in FIG. 1A, in the resist coating apparatus 100 in a state before the photoresist is applied, the intake valve 12 provided in the suction / pressure nozzle 8 is closed and the exhaust valve 11 is opened. The switching tank 10 connects the resist tank 6 and the suction side of the pump 13 so as to communicate with each other, and the pressure P ₂ in the resist tank 6 is changed to the pressure P in the coating chamber 2 by the driven pump 13. _The pressure is lower than ₁ (pressure P ₂ <pressure P ₁ ). The pressure P ₂ of the resist tank 6 is detected by the pressure sensor 15, operation of the pump 13 to a predetermined pressure is controlled. On the other hand, since the check valve 19 inserted in the middle of the liquid feeding pipe 3 is closed, the inflow of gas such as air from the coating chamber 2 is blocked.
The pressure P ₂ in the resist tank 6 that is in a reduced pressure state compared to the inside of the coating chamber 2 is not particularly limited. For example, when the pressure P ₁ in the coating chamber 2 is atmospheric pressure (0.1011325 MPa), 0.1 MPa or less, preferably 0.05 MPa or less, more preferably 0.001 MPa or less. Since the pressure P ₂ in the resist tank 6 is in a depressurized state lower than the pressure P ₁ in the coating chamber 2, the photoresist solution 5 stored in the resist tank 6 is degassed, and the photoresist solution The dissolved gas in 5 is removed.

Subsequently, as shown in FIG. 1B, the intake valve 12 provided in the suction / pressurization nozzle 8 is opened and the exhaust valve 11 is closed. The pressure P ₃ in the resist tank 6 is made higher than the pressure P ₁ in the coating chamber 2 by the pump 13 that is connected so as to be in communication with the exhaust side (pressure P _1). <pressure _P 3). On the other hand, when the inside of the resist tank 6 is in a pressurized state, the check valve 19 inserted in the middle of the liquid feed pipe 3 causes the photoresist liquid 5 to be fed from the resist tank 6 to the coating chamber 2. The photoresist liquid 5 that has been opened and removed from the dissolved gas is sent to the coating chamber 2 side through the liquid feeding pipe 3, discharged from the coating nozzle 3 a, and applied to the glass master 1 by a predetermined amount. Further, by providing the buffer part 14 with the flow path gently expanded in the middle of the liquid feeding pipe 3, the pressurized photoresist liquid 5 is gently expanded in volume. Although not shown, the predetermined amount of the photoresist solution 5 fed to the coating chamber 2 is controlled via a controller.
When a predetermined amount of the photoresist solution 5 is discharged, the check valve 19 is closed and the resist tank 6 and the coating chamber 2 are shut off. On the other hand, the intake valve 12 provided in the suction / pressurization nozzle 8 is closed again and the exhaust valve 11 is opened. The switching valve 10 brings the registration tank 6 and the intake side of the pump 13 into communication with each other. the pressure P ₂ in the resist tank 6 sucked is, is lower than that pressure P ₁ inside the coating chamber 2, the gas dissolved in the photoresist solution 5 is degassed by.

Next, FIG. 2 is a figure explaining 2nd Embodiment of the resist coating apparatus with which this Embodiment is applied. Portions common to the resist coating apparatus 100 described above are denoted by the same reference numerals and description thereof is omitted. The resist coating apparatus 200 shown in FIG. 2 mechanically applies the photoresist solution 5 in the liquid feeding pipe 3 to the coating chamber 2 side in the middle of the liquid feeding pipe 3 to which the resist tank 6 and the coating chamber 2 are connected. A tube pump 17 for feeding liquid is attached. The tube pump 17 is provided at a position closer to the resist tank 6 than the check valve 19.
As shown in FIG. 2, when the photoresist solution 5 is pressurized by the tube pump 17, the check valve 19 is opened, and after a predetermined amount of the photoresist solution 5 is fed to the coating chamber 2, the reverse is performed. The stop valve 19 is closed again, and the photoresist liquid 5 is prevented from flowing back through the liquid feeding pipe 3. Further, since the gas phase portion of the resist tank 6 and the suction side of the pump 13 are in communication with each other, and the inside of the resist tank 6 is always in a reduced pressure state, the dissolved gas in the photoresist solution 5 is degassed. Has been.

Hereinafter, the present embodiment will be described more specifically based on examples. The present embodiment is not limited to the examples.
(Example 1)
Using the resist coating apparatus 100 shown in FIG. 1A, the photoresist solution 5 was applied on the glass master 1. The pressure P ₁ in the coating chamber 2 is set to atmospheric pressure (0.1001325 MPa), and the pressure P ₂ in the resist tank 6 is 3 (1a) 0.1 MPa, (1b) 0.05 MPa, and (1c) 0.01 MPa. Under the same conditions, the resist tank 6 and the suction side of the pump 13 were in communication with each other, and the photoresist solution 5 was deaerated for a predetermined time under each condition. Next, an exhaust side of the registration tank 6 and the pump 13 to communicate with each other by adjusting the switching valve 10, the pressure P ₃ of the resist tank 6 is raised to 0.2 MPa, photoresist is opened the check valve 19 30 ml of the liquid 5 was discharged and applied onto the glass master 1 (φ200 mm). By the same operation, the photoresist solution 5 was applied on a total of 10 glass masters.
Next, the glass master 1 coated with the photoresist solution 5 was attached to an exposure apparatus, and was exposed every 0.5 μm in the radial direction of the glass master. At this time, the location where the focus error occurred was detected from the coordinates, and the number of bubbles generated was observed and counted with a microscope. The results are shown in Table 1.

(Example 2)
The photoresist solution 5 was applied on the glass master 1 using the resist coating apparatus 200 shown in FIG. The pressure P ₁ in the coating chamber 2 is set to atmospheric pressure (0.1001325 MPa), and the pressure P ₂ in the resist tank 6 is 3 (1a) 0.1 MPa, (1b) 0.05 MPa, and (1c) 0.01 MPa. Under the same conditions, the resist tank 6 and the suction side of the pump 13 were in communication with each other, and the photoresist solution 5 was deaerated for a predetermined time under each condition. Next, the tube pump 17 is driven, the pressure in the liquid feeding pipe 3 is increased, the check valve 19 is opened, 30 ml of the photoresist liquid 5 is discharged, and applied onto the glass master 1. In the same procedure, the number of bubbles generated on the glass master was observed with a microscope and counted. The results are shown in Table 1.

(Comparative example)
The photoresist solution 5 was applied on the glass master 1 using the resist coating apparatus 300 shown in FIG. The pressure in the coating chamber 2 is set to atmospheric pressure (0.1001325 MPa), the pressure in the resist tank 6 is increased to 0.2 MPa, the check valve 19 is opened, and 30 ml of the photoresist liquid 5 is discharged. The number of bubbles generated on the glass master disk was counted by observing with a microscope in the same manner as in Example 1 and coating on the glass master disk 1. The results are shown in Table 1.

  From the results of Table 1, dissolved gas in the photoresist solution is present on the glass master plate (Example 1 and Example 2) on which the photoresist is applied by the resist coating apparatuses 100 and 200 to which the present embodiment is applied. It can be seen that almost no bubbles are generated by foaming and the glass master production process is greatly improved. On the other hand, a large number of bubbles due to foaming of dissolved gas in the photoresist solution were observed on the glass master disk on which the photoresist was applied using the conventional resist apparatus 300 (comparative example). In particular, it can be seen that the minimum value (6) of the number of bubbles observed in the comparative example significantly exceeds the maximum value (3) of the number of bubbles observed in Example 1 or Example 2.

  Thus, according to the present embodiment, the dissolved gas in the photoresist solution was greatly reduced, and as a result, the foaming that appeared on the surface of the photoresist applied on the glass master was lost and manufactured. Defects on the glass master are greatly reduced.

  According to the photoresist coating method of the present invention, dissolved gas in a photoresist can be removed in a semiconductor manufacturing process in which a photoresist is coated on a Si substrate.

It is a figure explaining the resist coating apparatus with which this Embodiment is applied. FIG. 1A shows a state before the photoresist is applied, and FIG. 1B shows a state where the photoresist is applied. It is a figure explaining 2nd Embodiment of the resist coating apparatus with which this Embodiment is applied. It is a figure explaining the conventional resist coating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass master disk, 2 ... Coating chamber, 3,33 ... Liquid feeding piping, 3a, 33a ... Coating nozzle, 3b, 33b ... Resist suction port, 3c, 33c ... Valve, 5 ... Photoresist liquid, 6,36 ... Resist Tank, 8 ... Suction / pressurization nozzle, 10 ... Switching valve, 11 ... Exhaust valve, 12 ... Intake valve, 13 ... Pump, 14 ... Buffer, 15 ... Pressure sensor, 16 ... Line, 17 ... Tube pump, 19 ... Check valve, 37 ... Nozzle for pressurization, 100, 200, 300 ... Resist coating device

Claims (9)

A resist tank in which a photoresist liquid applied on a glass master is stored and maintained in a predetermined reduced pressure state,
A liquid feed pipe through which the photoresist liquid applied on the glass master is transferred;
An internal pressure adjusting means for adjusting the resist tank to a predetermined internal pressure;
A resist coating apparatus comprising: a check valve that is provided in the middle of the liquid supply pipe and prevents a reverse flow of the photoresist liquid.   The resist tank is maintained in a predetermined reduced pressure state except when the photoresist liquid is applied on the glass master, and when the photoresist liquid is applied on the glass master, a predetermined pressure is applied. 2. The resist coating apparatus according to claim 1, wherein the resist coating apparatus is held in a state.   2. The internal pressure P1 further includes a coating chamber in which the photoresist solution is applied onto the glass master, and the resist tank is held at a predetermined internal pressure P2 lower than the internal pressure P1. Resist coating equipment.   The resist coating apparatus according to claim 3, wherein the internal pressure P1 is atmospheric pressure.   The internal pressure adjusting means includes a switching valve for switching a depressurized state or a pressurized state in the resist tank, a sensor for detecting the internal pressure of the resist tank, and the resist tank depressurizing according to the operation of the switch valve. 2. A resist coating apparatus according to claim 1, further comprising a pump to be pressurized.   2. The resist coating apparatus according to claim 1, further comprising a transfer means for mechanically transferring the photoresist liquid upstream of the check valve of the liquid supply pipe.   The resist coating apparatus according to claim 1, wherein the liquid feeding pipe is attached to a position of the resist tank farthest from the liquid surface of the photoresist liquid. An application method for applying a photoresist solution on a glass master,
Holding the photoresist solution in a predetermined reduced pressure state;
A predetermined amount of the photoresist liquid held in the reduced pressure state is transferred through a liquid supply pipe provided with a check valve that prevents a reverse flow of the photoresist liquid by a predetermined pressure,
A photoresist coating method, wherein the transferred predetermined amount of the photoresist solution is coated on the glass master. A method of manufacturing an optical disc comprising a step of preparing a master master for an optical disc in which a photoresist liquid is applied on a glass master,
The preparation process of the master disc for optical disc is as follows:
A depressurization step of holding the photoresist solution in a predetermined depressurized state while storing the photoresist solution;
A transfer step of transferring the predetermined amount of the photoresist liquid held under reduced pressure through a liquid supply pipe provided with a check valve that prevents a reverse flow of the photoresist liquid by a predetermined pressure;
An application step of applying a predetermined amount of the photoresist liquid transferred in the transfer step onto the glass master;
An optical disc manufacturing method characterized by comprising:

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