JPH10106048A - Method of making and processing stamper for information recording disk and device therefor, and stamper and information recording disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate peeling failure between each stamper and unevenness of peeling on disk substrate surface by electrolytic etching the stamper after an electrolytic cleaning process which is one of a stamper making processing operation. SOLUTION: During a processing operation of stamper 5, when a stamper consisting of a metal layer and a plating layer has been peeled off from a glass master disk, this stamper 5 is connected with a switching circuit 7 and immersed in electrolytic bath 2 filled with electrolytic solution 3. A polarity of a voltage is changed over with the switching circuit 7 so that an electrode 4 becomes an anode and the stamper 5 becomes a cathode. Thus, resist, etc., adhered to the surface of the stamper 5 are electrclytically cleaned. Next, the voltage polarity is changed over with the switching circuit 7 so that the electrode 4 becomes a cathode and the stamper becomes an anode. Thus, the surface of the stamper 5 is electrolytically etched and an oxide film is formed thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a stamper for molding an information recording disk, a stamper produced by the method or the apparatus, and an information recording apparatus formed by the stamper. It is about a disk.

[0002]

2. Description of the Related Art Information recording disks include, for example, optical disks such as compact disks from which information is reproduced using light. An optical disk device for reproducing information on the optical disk operates, for example, as follows. That is, a light emitting element of an optical pickup built in an optical disk device irradiates a signal recording surface of a rotationally driven optical disk with light such as a laser beam, and a light receiving element of the optical pickup emits a signal recording surface of the optical disk. , And converts it into an information signal. Then, a reproducing circuit built in the optical disk device reproduces information by reading the information signal.

Such an optical disk has a disk substrate formed of a transparent synthetic resin material such as polycarbonate (PC) and polymethyl methacrylate (PMMA). This disk substrate is injection molded using a stamper described later. On the main surface of the disk substrate,
An information signal layer in which an information signal is recorded by predetermined information pits is provided, and a reflection film such as an aluminum thin film for reflecting light is formed on a surface of the information signal layer. .

[0004] A protection layer is provided for mechanically and chemically protecting the information signal layer. This optical disk has a single-layer structure, and its transparent disk substrate usually has a structure of 1.
It has a thickness of 2 mm. Light from the light emitting element passes through the disk substrate and irradiates the information signal layer. And
A phase change of the return light reflected by the reflective film formed on the information signal layer is detected by the light receiving element.

FIG. 12 is a flowchart showing a conventional stamper creation processing method. First, the remaining nickel, resist and the like are removed from the used glass master, and the surface thereof is polished to regenerate the glass master. Then, the glass master is cleaned by ultrasonic cleaning or the like to remove the remaining abrasive (step STP1). Next, the glass master is dried, and a resist (HMDS) is applied to the surface to form a resist layer (step STP2).

Subsequently, a desired information signal is exposed and recorded (cut) on the resist layer (step STP3).
The exposed portion is removed by developing the resist layer to form a concavo-convex pattern (pit) composed of the remaining resist layer (step STP4). Further, a thin metal layer is formed (metallization) on the surface of the resist layer by sputtering, vapor deposition, electroless plating or the like (Step S).
TP5) A plating layer having a predetermined thickness is formed on the metal layer by plating (electroforming) (step STP6).

After that, the portion composed of the metal layer and the plating layer is peeled off from the glass master, and the resist or the like adhering to the transfer pit surface is electrolytically cleaned to obtain a metal master stamper (step STP7). Then, a mother stamper is created using the metal master stamper as a prototype, and a stamper is created using the mother stamper as a prototype. Next, the stamper is dried, a protective film layer is formed, the back surface is polished (Step STP8), and a post-process such as removal of an excess portion by punching with a press or the like is performed (Step STP9). A good stamper. Then, the stamper thus prepared is set in an injection mold, and a disk substrate is injection-molded.

[0008]

In the above-described conventional stamper creation processing method, as shown in FIGS. 13A to 13C, for example, when a mother stamper is created using a metal master stamper as a prototype, a metal master stamper is used. When the mother stamper is separated from the stamper, there is a problem that the transfer pits of the mother stamper may be cut off as shown by the dotted lines in the drawing due to defective separation between the transfer pits.

In addition, when the stamper is set in an injection molding die and the disc substrate is injection-molded, there is a problem that uneven peeling may occur on the surface of the disc substrate. This peeling unevenness occurs during injection molding and immediately after cooling,
Due to the shrinkage of the molded disk substrate, the disk substrate is pulled obliquely when it is released from the stamper, and one side of the information pit on the disk substrate is caught at the corner of the transfer pit of the stamper It is. In particular, the higher the density of the disk, the sharper the inclination angle of the transfer pit and the smaller the taper, so that
Peeling unevenness is likely to occur.

SUMMARY OF THE INVENTION In view of the above, the present invention provides a method and an apparatus for forming a stamper for an information recording disk, which can eliminate peeling failure between the stampers and uneven peeling of the disk substrate surface, and a stamper and an information recording disk. It is intended to provide.

[0011]

According to the present invention, the stamper is subjected to an electrolytic etching process after an electrolytic cleaning process, which is one of the processes for producing a stamper for molding an information recording disk. This is achieved by:

According to the above configuration, since the stamper is subjected to the electrolytic etching process, the surface of the stamper can be modified, and the separation from the stamper or the disk substrate can be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The embodiments described below are preferred specific examples of the present invention,
Although various technically preferred limitations are given, the scope of the present invention is not limited to these forms unless otherwise specified in the following description.

FIG. 1 is a schematic configuration diagram showing a first embodiment of a processing apparatus for producing a stamper for an information recording disk according to the present invention. This stamper creation processing apparatus 1 is shown in FIG.
This is an electrolytic processing apparatus used in the electrolytic cleaning processing (step STP7) shown in FIG.

An electrolytic solution 3 is injected into the tank 2 and an electrode 4
And, for example, a metal master stamper (hereinafter simply referred to as a stamper) 5 is immersed in the tank 2 filled with the electrolyte 3. Further, the electrode 4 and the stamper 5 are connected to the DC power supply 6 so that an applied voltage from the DC power supply 6 can be applied via the switching circuit 7. Further, a pipe 8, a liquid feed pump 9 and a filter 10 are connected to the tank 2 so that the electrolyte 3 in the tank 2 can be circulated and filtered. As the electrolytic solution 3, for example, sodium pyrophosphate, trisodium phosphate, or the like is used. As the electrode 4, a conductive member such as stainless steel is used. Note that a pulse power supply or the like may be used instead of the DC power supply 6.

An example of the processing operation in such a configuration will be described. During the step of forming and processing the stamper 5, when the stamper 5 composed of the metal layer and the plating layer is peeled off from the glass master, the stamper 5 is connected to the switching circuit 7 and is placed in the tank 2 filled with the electrolyte 3. Immerse. For connection between the stamper 5 and the switching circuit 7, for example, a jig for attaching the stamper 5 is used.

The DC power supply 6 applies a voltage to the electrode 4 and the stamper 5 via a switching circuit 7. At this time, the switching circuit 7 includes a positive electrode (anode) for the electrode 4 and a negative electrode (cathode) for the stamper 5. Switch the polarity of the voltage so that Thus, the resist or the like adhering to the surface of the stamper 5 is subjected to electrolytic cleaning (cathode cleaning). At this time, the chemical reaction formula on the electrode 4 (positive electrode (anode)) side is represented by Chemical Formula 1, and the chemical reaction formula on the stamper 5 (negative electrode (cathode)) side is represented by Chemical Formula 2.

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Next, the switching circuit 7 switches the polarity of the voltage so that the electrode 4 becomes a negative electrode (cathode) and the stamper 5 becomes a positive electrode (anode). Thus, the surface of the stamper 5 is electrolytically etched and an oxide film is formed (anodized). In this case, the chemical reaction formula on the electrode 4 (negative electrode (cathode)) side is represented by Chemical Formula 3, and the chemical reaction formula on the stamper 5 (positive electrode (anode)) side is represented by Chemical Formula 4.

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Before and after and during the electrolytic cleaning and electrolytic etching, the liquid feed pump 9 circulates the electrolytic solution 3 in the tank 2 through the pipe 8, and filters the impurities contained in the electrolytic solution 3 through the filter 10. Is filtered.

FIG. 2 is a schematic configuration diagram showing a second embodiment of a processing apparatus for producing a stamper for an information recording disk according to the present invention. This stamper creation processing device 20 is also shown in FIG.
This is an electrolytic processing apparatus used for the electrolytic cleaning process (Step STP7) shown in FIG. 2 and for the subsequent electrolytic etching process.

A turntable 22 on which the stamper 5 is mounted and which rotates is disposed in a lower part of the tank 21, and an electrode having a plurality of holes for pouring the electrolyte 3 is provided on the upper part of the turntable 22. A mold nozzle 23 is provided. Further, the turntable 22 and the electrode type nozzle 23 are connected to a power supply 24 so that an applied voltage from a power supply 24 having a built-in switching circuit can be applied.

Further, a pipe 25, a tank 26, a liquid feed pump 27 and a filter 28 are connected to the tank 21 so that the electrolyte 3 accumulated in the lower part of the tank 21 can be circulated and filtered. Examples of the electrolyte 3 include sodium pyrophosphate,
Trisodium phosphate or the like is used. Turntable 2
A conductive member such as stainless steel is used for the second and electrode type nozzles 23. Note that a DC power supply, a pulse power supply, or the like is used as the power supply 24.

An example of the processing operation in such a configuration will be described. When the stamper 5 including the metal layer and the plating layer is peeled off from the glass master during the process of forming the stamper 5, the stamper 5 is placed on the turntable 22. Then, the turntable 22 is rotated, and the liquid sending pump 27 is driven to drop the electrolyte 3 from the hole of the electrode type nozzle 23 to the stamper 5.

The power supply 24 applies a voltage to the turntable 22 and the electrode type nozzle 23. At this time, the switching circuit makes the electrode type nozzle 23 a positive electrode (anode) and the turntable 22 a negative electrode (cathode). Switches the voltage polarity. Thus, the resist or the like adhering to the surface of the stamper 5 is subjected to electrolytic cleaning (cathode cleaning).

Next, the polarity of the voltage is switched by a switching circuit so that the electrode type nozzle 23 becomes a negative electrode (cathode) and the turntable 22 becomes a positive electrode (anode). Thus, the surface of the stamper 5 is electrolytically etched and an oxide film is formed (anodized). The liquid supply pump 27 circulates the electrolytic solution 3 in the tank 26 through the pipe 25 before and after or during the electrolytic cleaning and electrolytic etching processes, and filters impurities contained in the electrolytic solution 3 by the filter 28. .

FIG. 3 is a schematic configuration diagram showing a third embodiment of a processing apparatus for producing a stamper for an information recording disk according to the present invention. This stamper creation processing device 30 is shown in FIG.
2 is an electroforming / electrolysis processing apparatus used in the electroforming process (step STP6) and the electrolytic cleaning process (step STP7) shown in FIG. 2 and used in the subsequent electrolytic etching process. It was done.

The electrolytic solution 3 is injected into the tank 31,
An electrode 32 is arranged in a lower part of the inside 1, and an electrode type rotary head 33 that rotates by attaching the stamper 5 is arranged above the electrode 32. Further, the electrode 32 and the electrode type rotary head 33 are connected to a power source
It is connected to the. As the electrolytic solution 3, for example, sodium pyrophosphate, trisodium phosphate, or the like is used. As the electrode 32 and the electrode type rotary head 33, a conductive member such as stainless steel is used. Note that a DC power supply, a pulse power supply, or the like is used as the power supply 34.

An example of the processing operation in such a configuration will be described. In the process of forming the stamper 5, if a thin metal layer is formed (metallization) on the surface of the resist layer by sputtering, vapor deposition, electroless plating, or the like, it is attached to the electrode type rotary head 33 and rotated. An electroforming process for forming a plating layer having a predetermined thickness on the layer by plating (electroforming) is performed in the same manner as in the related art.

Next, the power supply 34 applies a voltage to the electrode 32 and the electrode type rotary head 33. At this time, the switching circuit makes the electrode 32 a positive electrode (anode) and the electrode type rotary head 33 a negative electrode (cathode). Switch the polarity of the voltage so that Thus, the resist or the like adhering to the surface of the stamper 5 is subjected to electrolytic cleaning (cathode cleaning). Next, the polarity of the voltage is switched by the switching circuit so that the electrode 32 becomes a negative electrode (cathode) and the electrode type rotary head 33 becomes a positive electrode (anode). Thus, the surface of the stamper 5 is electrolytically etched and an oxide film is formed (anodized).

By the above-described electrolytic etching, FIG.
As shown in (A), the current can be concentrated on the edge of the top of the transfer pit 5a of the stamper 5, so that the edge can be made smooth and the land or groove surface 5b of the stamper 5 can be appropriately adjusted. Can be devastated. Since the edge of the top of the transfer pit 5a of the stamper 5 can be made smooth in this manner, the removability between the stamper 5 and the mother stamper 11 can be improved,
The deformation of the transfer pit 11a of the mother stamper 11 can be prevented.

Further, since the surface 5b of the land or groove of the stamper 5 can be appropriately roughened, the final stamper formed by this stamper 5 has a moderately roughened surface and the final stamper is brought into close contact with the disk substrate. The force can be reduced, the releasability of the disk substrate can be improved, and the occurrence of peeling unevenness on the disk substrate surface can be prevented (FIGS. (B) and (C)).

FIGS. 5 to 1 show the surface condition of the stamper 5 when the stamper 5 is processed under the following electrolytic solution 3 and electrolysis conditions using the processing apparatus for producing a stamper for an information recording disk described above.
It is shown in FIG. As the electrolytic solution, 10 g / l of sodium pyrophosphate and 10 g / l of trisodium phosphate were each used for 1.
A mixed solution of 0 wt% was used at 50 ° C. As the electrolysis conditions, the distance between the electrodes was 5 cm, and the current density was 6.4 A.
/ Dm2 (voltage 7.5 V, current 20 A, electrode plate area 314
cm2) and the electrolysis time was 30 seconds × (1 to 10 times).

FIG. 5 is an electron micrograph showing an example of the surface state of the compact disk (CD) stamper 5 that has not been subjected to the above treatment. FIG. 6 shows the above treatment (the electrolysis time is 30 seconds × 3 times). ) Compact disc (C
4 is an electron micrograph showing an example of a surface state of a stamper 5 for D). As is clear from the above, by performing the above processing, the edge of the top of the transfer pit 5a of the stamper 5 can be made smooth, and the land or groove surface 5b of the stamper 5 can be appropriately roughened.

FIG. 7 is an electron micrograph showing an example of the surface state of the stamper 5 for a digital video disk (DVD) that has not been subjected to the above-described processing. FIGS. Second × 1 time, 30 seconds × 3 times, 30
5 is an electron micrograph showing an example of the surface state of a stamper 5 for a digital video disk (DVD) that has been subjected to (sec × 5 times, 30 sec × 10 times). In FIG. 8, the land surface 5b
Is a bit rough. 9 and 10, the transfer pit 5
a The top edge and the land surface 5b are moderately rough. In FIG. 11, the transfer pit 5a and the entire surface 5b of the land or groove are extremely dissolved.

As is apparent from the above, by performing the above-described processing, the edge of the top of the transfer pit 5a of the stamper can be made smooth and the land or groove surface 5b of the stamper 5 can be appropriately roughened. .
Then, by changing the electrolysis conditions (for example, electrolysis time), the surface roughness of the land or groove of the stamper 5 can be freely controlled.

[0036]

As described above, according to the present invention,
The occurrence rate of defective stampers can be reduced, and the yield and quality of the disk substrate can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a processing apparatus for creating a stamper for an information recording disk according to the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of a processing device for producing a stamper for an information recording disk according to the present invention.

FIG. 3 is a schematic configuration diagram showing a third embodiment of a stamper creation processing device for an information recording disk according to the present invention.

FIG. 4 is a cross-sectional side view showing a processing state of the information recording disk stamper creation processing apparatus shown in FIGS. 1 to 3;

FIG. 5 is a first photograph showing a surface state of a normal stamper.

FIG. 6 is a first photograph showing a surface state of the stamper shown in FIG. 5 which has been processed by the information recording disk stamper creation processing apparatus shown in FIGS.

FIG. 7 is a second photograph showing a surface state of a normal stamper.

8 is a first photograph showing the surface state of the stamper shown in FIG. 7 which has been processed by the information recording disk stamper creation processing apparatus shown in FIGS.

9 is a second photograph showing the surface state of the stamper shown in FIG. 7 which has been processed by the information recording disk stamper creation processing apparatus shown in FIGS.

10 is a third photograph showing the surface state of the stamper shown in FIG. 7 that has been processed by the information recording disk stamper creation processing apparatus shown in FIGS.

11 is a fourth photograph showing the surface state of the stamper shown in FIG. 7 processed by the information recording disk stamper creation processing apparatus shown in FIGS.

FIG. 12 is a flowchart showing a conventional stamper creation processing method.

FIG. 13 is a cross-sectional side view showing a processing state of a conventional information recording disk stamper creation processing apparatus.

[Explanation of symbols]

1, 20, 30... Stamper creation processing device, 2, 2
Reference numerals 1, 31, tank, 3 electrolyte, 4, 32 electrode, 5 stamper, 5a transfer pit, 5b
..Surfaces 5b and 6 of lands and grooves DC power supply
7: switching circuit, 8, 25: piping, 9,
27: liquid feed pump, 10, 28: filter, 2
2 ... turntable, 23 ... electrode type nozzle, 2
4, 34: power supply, 26: tank, 33: electrode type rotary head print layer

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[Procedure amendment]

[Submission date] December 17, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5 is a first micrograph showing a surface state of a normal stamper.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6 is a first photomicrograph showing a surface state of the stamper shown in FIG. 5 which has been processed by the information recording disk stamper creation processing apparatus shown in FIGS.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Fig. 7

[Correction method] Change

[Correction contents]

FIG. 7 is a second micrograph showing the surface state of a normal stamper.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] Fig. 8

[Correction method] Change

[Correction contents]

8 is a first photomicrograph showing a surface state of the stamper shown in FIG. 7 which has been processed by the information recording disk stamper creation processing apparatus shown in FIGS.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] Fig. 9

[Correction method] Change

[Correction contents]

9 is a second photomicrograph showing the surface state of the stamper shown in FIG. 7 that has been processed by the information recording disk stamper creation processing apparatus shown in FIGS.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 10 is a third micrograph showing the surface state of the stamper shown in FIG. 7 which has been processed by the information recording disk stamper creation processing apparatus shown in FIGS.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 11 is a fourth microscope photograph showing the surface state of the stamper shown in FIG. 7 which has been processed by the information recording disk stamper creation processing apparatus shown in FIGS.

Claims (4)

[Claims] 1. An electrolytic cleaning process, which is one of the processes for producing a stamper for molding an information recording disk,
A method for producing a stamper, comprising subjecting the stamper to electrolytic etching. 2. A stamper producing apparatus for continuously performing an electrolytic cleaning process and an electrolytic etching process as a process for producing a stamper for molding an information recording disk, wherein a positive or negative voltage is applied to the stamper. Voltage applying means for applying a negative or positive voltage to the electrolytic solution, and switching to apply a negative voltage to the stamper and a positive voltage to the electrolytic solution during the electrolytic cleaning process, Switching means for switching so that a positive voltage is applied to the stamper and a negative voltage is applied to the electrolyte during processing. 3. A stamper for molding an information recording disk on which information is recorded by information pits formed on the surface, wherein a transfer surface for molding the surface by performing an electrolytic cleaning process and an electrolytic etching process. Characterized in that the surface of the transfer pit for forming the information pit is smooth and the edge of the top of the transfer pit for forming the information pit is smooth. 4. An information recording disk on which information is recorded by information pits formed on the surface, wherein an electrolytic cleaning process and an electrolytic etching process are performed to uniformly and appropriately transfer a transfer surface for forming the surface. An information recording disk having a rough surface formed by a stamper having a smooth top edge of a transfer pit for forming said information pit.