JP2001354450A - Method for regenerating glass substrate for stamper and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily treat a glass substrate in a short time by preventing environmental pollution by the use of nitric acid. SOLUTION: Sulfuric acid and a hydrogen peroxide solution are allowed to act on the surface of a glass substrate. The hydrogen peroxide solution acts as a catalyst and the velocity of dissolution of nickel is accelerated. Since nitric acid is not used, environmental pollution due to nitric acid mist is not caused.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and apparatus for reproducing a glass substrate for manufacturing a stamper for mass-producing optical disks and the like.

[0002] A stamper (die) for manufacturing an optical disk is
Glass substrate cleaning, resist coating, cutting, development, nickel electroforming, electroformed metal (nickel)
Is peeled off from the glass substrate, and is subjected to a predetermined finishing treatment. It is general that the glass substrate from which the metal has been peeled is subjected to a predetermined treatment, and further subjected to a polishing step as required, and repeatedly reused. However, the nickel component and the resist component in the above process remain on the glass substrate after the metal is stripped. Therefore, in order to reuse the glass substrate, it is necessary to perform a glass substrate recycling process such as removing remaining components.

[0003]

2. Description of the Related Art In a conventional method, a nitric acid solution or a ferric chloride solution is used as a nickel treatment solution for dissolving a residual nickel component, and a special release agent (remover) and an organic solvent (dissolver) are used for dissolving a resist component. In general, an acetone solution or the like or an alkali solution (such as sodium hydroxide) is used as a resist processing solution. More specifically, as shown in FIG. 2, the glass substrate 11 is sequentially immersed in the nickel treatment bath 12, the washing bath 13, and the resist treatment bath 14 to dissolve each remaining component.

The reaction of dissolving nickel with nitric acid is a dissolution reaction with an acid represented by the following formula, and the dissolution treatment time usually requires about 5 minutes. Ni + 2HNO ₃ → Ni (NO ₃ ) ₂ + H ₂

[0005] Ferric chloride is a metal dissolution reaction due to the difference in ionization tendency. That is, when a metal having a large ionization tendency is put in a salt having a small ionization tendency,
Metals having a high ionization tendency are dissolved (ionized). Ferric chloride (FeCl ₃ ) has a trivalent iron ion Fe (III). Since the ionization tendency is Ni≫Fe (III), the salt (ferric chloride) having a low ionization tendency and the ionization tendency Ni having a large value acts to dissolve Ni. However, since this reaction proceeds very slowly, a very long dissolution time (normally about 30 minutes) is required.

[0006]

In the above-mentioned conventional method, when nitric acid is used as a nickel treatment liquid, the surroundings are affected (such as contamination) by the generation of nitric acid mist and the like.
In addition, when ferric chloride is used, there is a problem that the processing time is extremely long because the dissolution rate is low. Also, the contamination is the same as when nitric acid is used. Further, it has been difficult to automate the glass substrate regeneration process due to the problem in the takt time and the device configuration due to the above-described processing method.

[0007]

In the present invention, sulfuric acid and hydrogen peroxide are used in place of nitric acid or ferric chloride in the conventional method for dissolving nickel components. The concentration of the aqueous solution is preferably 10 to 30% for sulfuric acid and 10 to 30% for aqueous hydrogen peroxide. The concentration of the treatment liquid may be appropriately determined depending on the amount of nickel remaining on the glass substrate. In the case of this processing solution, the dissolution rate of nickel is usually 2 to
In 3 minutes, it is faster than with nitric acid, and thus the dissolution time can be reduced. Further, since there is no generation of mist such as nitric acid and there is no need to soak in the processing liquid tank for a long time unlike ferric chloride, the nozzle is placed on the upper surface of a glass substrate installed on a table (preferably a rotary table). , A nickel dissolution treatment by a method of discharging the treatment liquid becomes possible. Furthermore, resist dissolution processing, washing with water, etc. can be performed on the same table by a method using nozzle discharge.
Automation and automatic equipment which were difficult in the past can be realized.

[0008] The nickel dissolution reaction with sulfuric acid and aqueous hydrogen peroxide in the present invention is as follows. In this reaction,
The aqueous hydrogen peroxide acts as a catalyst and promotes nickel dissolution.

When an alkaline solution (such as a sodium hydroxide solution) is used for the resist dissolution treatment, each treatment liquid causes a neutralization reaction in the waste liquid in which the nickel treatment liquid and the resist treatment liquid are mixed. In particular, if the amount of the nickel treatment solution (sulfuric acid and hydrogen peroxide solution) and the amount of the resist treatment solution (alkali solution) are set to substantially neutralize each other, the waste liquid becomes almost neutral, and the special waste liquid There is no need to perform any processing.

[0010]

FIG. 1 is a schematic view of a glass substrate reproducing apparatus according to an embodiment. The apparatus shown in FIG. 1 is a rotary table 2 on which a glass substrate 1 is set, a nickel processing liquid nozzle 3 for discharging a nickel processing liquid, a resist processing liquid nozzle 4 for discharging a resist processing liquid, and discharges water for washing. A washing nozzle 5, a liquid collecting means 9 for collecting the liquid discharged from each of these nozzles, and a waste liquid tank 8 for storing the collected liquid
Having. The rotation table 2 is rotated at a predetermined programmed rotation speed by a motor (not shown). The nickel processing liquid nozzle 3 is connected to a tank 6 for storing a nickel processing liquid in which sulfuric acid and a hydrogen peroxide solution (sulfuric acid) are previously adjusted to a predetermined concentration and a mixing ratio. A tank 7 for storing a resist processing solution such as sodium hydroxide having a predetermined concentration is connected. Each processing solution is
The liquid is discharged toward the surface of the glass substrate 1 set on the table 2 by a discharging means such as a pump through a filter as necessary.

As a specific example, the rotation table 2
Alternatively, the glass substrate 1 is manually set and rotated at a low speed. Next, after washing with the washing nozzle 4, the nickel treatment liquid in the tank 6 in which the nickel treatment liquid prepared in advance is stored is discharged from the nozzle 3 by a discharge means (not shown) such as a pump to remove nickel. Next, water is discharged from the rinsing nozzle 5 to rinse the nickel processing liquid remaining on the glass substrate 1 with water, and the resist processing liquid in the resist processing liquid tank 7 is discharged from the nozzle 4 by discharging means (not shown) such as a pump. Discharge and remove the resist. Next, water is discharged from the washing nozzle 5 to rinse and wash the resist treatment liquid remaining on the glass substrate 1 with water. Thereafter, the table is stopped, and the glass substrate is taken out automatically or manually and put into the next process. Such control of rotation / stop of the table 2 and discharge of the processing liquid and water from the nozzles can be performed fully automatically by a control means such as a computer.

The treatment liquid after each treatment and the water for washing are as follows:
The liquid is temporarily stored in the waste liquid tank 8 by the liquid collecting means 9, and is discharged after neutralizing the waste liquid.

The glass substrate recycling method of the present invention can perform processing on a rotary table, which was difficult with the conventional method, because the nickel melting processing time is short. This is more effective. Specifically, washing, nickel dissolution treatment, washing,
The steps of resist dissolution, cleaning, polishing, and cleaning can be automatically performed on the same table. Furthermore, utilizing the ease of transfer with other devices by the table structure,
If it is combined with an existing automatic device after the resist coating (a stamper manufacturing device that sequentially performs resist coating, cutting, development, electroforming, etc. on a glass substrate), a wider range of full automation can be realized. In any case, it is possible to automate a process which has been difficult to automate conventionally, and it is possible to efficiently recycle a glass substrate.

[0014]

According to the present invention, since the sulfuric acid and the hydrogen peroxide solution are used for the treatment liquid used for dissolving nickel, the dissolution rate of nickel is higher than that of the conventional method, and it is necessary to immerse in the treatment tank for a long time as in the conventional method. Therefore, it is possible to set a glass substrate on a table and discharge a processing liquid onto the substrate. Furthermore, resist dissolution processing in the same table,
Washing is also possible and automation can be easily performed. In addition, there is less contamination to the surroundings as compared with the conventional method. Further, the waste liquid can be easily drained by the neutralizing action between the processing liquids.

[Brief description of the drawings]

FIG. 1 is a schematic view of a glass substrate reproducing apparatus according to an embodiment.

FIG. 2 is an explanatory diagram of a conventional glass substrate recycling method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Table 3 Nickel processing liquid nozzle 4 Resist processing liquid nozzle 5 Rinse nozzle 6 Nickel processing liquid tank 7 Resist processing liquid tank 8 Waste liquid tank 9 Liquid collecting means 11 Glass substrate 12 Nickel processing liquid tank 13 Rinse tank 14 Resist processing liquid Tank

Claims (7)

[Claims] 1. A method for regenerating a glass substrate for a stamper, comprising a step of dissolving nickel by causing sulfuric acid and hydrogen peroxide to act on the surface. 2. A step of setting a glass substrate 1 on a table 2 and a step of performing a nickel dissolving treatment on the glass substrate 1 on the table 2 by applying a nickel treatment liquid obtained by mixing sulfuric acid and hydrogen peroxide solution. Recycling method of glass substrate for stamper characterized by having 3. The recycling method according to claim 2, wherein a resist dissolving treatment step of applying a resist treatment liquid to the glass substrate 1 on the same table 2 and a water washing step are performed after the nickel dissolving treatment step. Recycling method of glass substrate for stamper 4. The method for regenerating a glass substrate for a stamper according to claim 3, wherein a polishing step, a cleaning step, and a drying step are performed on the same table 2 after the water washing step. 5. The method for regenerating a glass substrate for a stamper according to claim 3, wherein the resist treatment liquid is an alkaline solution. 6. The method according to claim 5, wherein the amount of the nickel treatment liquid used in the nickel dissolution treatment step and the amount of the resist treatment liquid used in the resist dissolution treatment step are in amounts that substantially neutralize each other. A method for reclaiming a glass substrate for a stamper 7. An apparatus for regenerating a glass substrate for a stamper according to the method of claim 3, 4, 5 or 6, wherein the glass substrate 1 is placed on a table 2 and sulfuric acid is directed toward the glass substrate on the table 2. Processing liquid nozzle 3 for discharging a mixed liquid of hydrogen and hydrogen peroxide, and glass substrate 1 on table 2
Processing liquid nozzle 4 for discharging the resist processing liquid toward the nozzle, washing nozzle 5 for discharging water toward the glass substrate 1 on the table 2, and liquid collecting for collecting the liquid discharged from each of the nozzles 3, 4, 5 An apparatus for recycling a glass substrate for a stamper, comprising: means 9; and a waste liquid tank 8 for storing the collected liquid.