JPH0729223A - Production of stamper and device for polishing rear surface of stamper - Google Patents

Abstract

PURPOSE:To smoothly polish the rear surface of a stamper with high accuracy. CONSTITUTION:The stamper 4 is placed in tight contact with a glass master disk 5 on a turn table 6. A polishing head 2 smaller than the size of the stamper 4 is disposed to face the rear surface of the stamper 4. The polishing head 2 is stuck with a polishing cloth 1. This polishing head 2 is rotated and is moved back and forth toward a direction (x) while a polishing liquid is supplied between the stamper 4 and polishing cloth 1 at the time of polishing. The pressure acting on the polishing head 2 is detected by a pressure detecting means 13 and a feed mechanism 10 in a direction (z) is so driven with a control means 14 in such a manner that the specified pressure is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stamper back surface polishing apparatus used for mirror polishing the back surface of a stamper for forming an optical recording medium.

[0002]

2. Description of the Related Art Conventionally, as a means for efficiently handling a wide variety of information, an optical information recording method using an optical recording medium has been proposed, and an optical information recording carrier, a recording / reproducing method, and a recording / reproducing apparatus therefor have been proposed. ing. In such an optical recording medium as an information recording carrier, in general, a stamper on which a concavo-convex pattern corresponding to tracks and information is formed is prepared in advance, and a stamper is formed on a polycarbonate resin or polymethylmethacrylic resin which is a thermoplastic resin. A groove portion is formed by transferring the uneven pattern. Information recording and playback is
It is performed while positioning by the phase difference of the laser light by using the fine unevenness of the groove.

Now, a conventional stamper manufacturing process will be described. First, a glass master is prepared by laminating a resin layer having a concavo-convex pattern formed at a predetermined depth with a resist or a photosensitive resin on a glass substrate that has been polished with good flatness. Next, a conductive film is formed on the surface of the glass master by sputtering or the like. Then, an electroformed film is electrodeposited on the conductive film by electroforming. And after polishing the back surface of this electroformed film smoothly,
The stamper having the concavo-convex pattern formed on the surface is obtained by peeling the conductive film and the resin layer at the interface. If the back surface of the stamper has irregularities, the transferred pattern will be distorted or the transferred irregularities will adversely affect the servo performance and data detection performance.Therefore, the back surface of the stamper must be polished as smooth as possible. is there.

As a device for polishing the back surface of such a stamper, for example, a dry polishing device in which a belt-shaped rotary polishing body is brought into contact with the back surface of the stamper while simply moving the stamper, or a stamper is provided on the back surface of the stamper. There is a so-called lapping device, which is larger than the size and has a rotating disk having a polishing cloth attached to the surface thereof, which faces each other, and supplies the polishing liquid between them to rotate them in opposite directions to each other. There are the following two methods of polishing with a lapping device. Before the stamper is polished, the stamper is peeled off from the glass master, and the pattern surface is covered with a protective film and then polished.
Polish with the stamper in close contact with the glass master.

[0005]

However, among the above-mentioned conventional polishing apparatuses, in the dry type in which the belt-like rotary polishing body is brought into contact with the back surface of the stamper, the polishing powder generated during polishing and dust from the surroundings are generated. However, there is a problem in that the scratches are likely to be generated on the polished surface due to the inclusion of

On the other hand, in polishing with a lapping device, the shape of the back surface of the stamper depends on the thickness of the protective film, the shape of the warp of the master, and the like, and a rotating disk larger than the stamper is applied to the back surface of the stamper. Since the polishing is performed in contact with each other, the stamper is not polished to a certain thickness when the polishing is performed in a state where the thickness of the protective film is varied or the master is warped. That is, there is a problem that the stamper peeled from the protective film or the master does not have a constant thickness and a smooth stamper cannot be obtained. Further, since the lapping and polishing apparatus has a relatively large rotating platen and its rotating mechanism, it is difficult to downsize the apparatus.

It is an object of the present invention to provide a stamper manufacturing method and a stamper back surface polishing apparatus that can polish the back surface of the stamper more accurately and smoothly.

[0008]

In order to achieve the above-mentioned object, the stamper manufacturing method of the present invention is such that a conductive film and an electroformed film are sequentially formed on the surface of a master having an uneven pattern corresponding to information to be recorded. Forming a stamper that is composed of the conductive film and the electroformed film and has the electroformed film as a back surface by stacking, and after peeling the back surface of the stamper, peeling the stamper at the interface between the master and the conductive film. In the method of manufacturing a stamper for obtaining a stamper for forming an optical recording medium, in polishing the back surface of the stamper, the surface of the stamper is smaller than the size of the back surface of the stamper and faces the back surface of the stamper. Using a polishing head with a fixed polishing cloth, while reciprocating the polishing head in the radial direction of the stamper along the shape of the back surface of the stamper while rotating,
A polishing liquid is supplied between the polishing cloth and the back surface of the stamper to polish the back surface of the stamper.

Further, by controlling the position of the polishing head so that the pressure applied to the polishing head becomes constant by bringing the polishing cloth into contact with the back surface of the stamper,
The polishing head may be moved along the shape of the back surface of the stamper.

In the stamper back surface polishing apparatus of the present invention, the conductive film and the electroformed film formed by sequentially laminating the conductive film and the electroformed film on the surface of the master on which the concavo-convex pattern corresponding to the information to be recorded are formed. A stamper for forming an optical recording medium, which is composed of an electroformed film and has the electroformed film as a back surface, is placed through the master in a state of being in close contact with the master, and a rotary table rotatably provided. , Rotatable and reciprocally movable in the radial direction of the stamper, smaller than the size of the back surface of the stamper, and a polishing cloth is fixed to the surface facing the back surface of the stamper mounted on the rotary table. And a polishing liquid supply means for supplying a polishing liquid between the polishing head and the back surface of the stamper.
When the back surface of the stamper is polished, the polishing head further includes a drive unit that moves the polishing head along the shape of the back surface of the stamper together with the reciprocating movement of the polishing head in the radial direction of the stamper.

Further, the driving means has a pressure detecting means for detecting a pressure applied to the polishing head when the polishing cloth is in contact with the back surface of the stamper, and the pressure detected by the pressure detecting means is constant. As described above, a control means for controlling the position of the polishing head may be provided.

[0012]

In the method of manufacturing a stamper of the present invention configured as described above, when the back surface of the stamper is polished, the polishing liquid is supplied between the polishing cloth fixed to the polishing head and the stamper. By combining the etching effect and mechanical polishing with abrasive particles, the back surface of the stamper is finished into a mirror surface with few scratches. Further, since the stamper is formed by sequentially laminating a conductive film and an electroformed film on the surface of the master, the thickness thereof is constant, and the shape of the back surface depends on the shape of the master. That is, when the master disc is warped or the like, the back surface of the stamper is also warped. Therefore, by using a polishing head whose size is smaller than the size of the back surface of the stamper and moving the polishing head along the shape of the back surface of the stamper, the thickness of the polished stamper is kept constant. After being peeled off from the master, the back surface becomes smooth.

[0013]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an embodiment of a stamper back surface polishing apparatus of the present invention. In FIG. 1, a rotary table 6 is rotatably provided in a θz direction by a table rotary motor 7, and a stamper 4 is mounted on the upper surface thereof. As shown in FIG. 2, the stamper 4 includes a conductive film 4a formed on the surface of a glass master 5 in which a resin layer 5b having a concavo-convex pattern formed at a predetermined depth is laminated on a glass substrate 5a polished to have a good flatness. It is a laminate with the electroformed film 4b,
As shown in FIG. 1, the glass master 5 side is placed on the rotary table 6 while being in close contact with the glass master 5. That is, the back surface of the stamper 4 is directed upward in the figure. Further, a trough-shaped polishing liquid receiver 8 for receiving the polishing liquid supplied at the time of polishing the stamper 4 is arranged so as to surround the rotary table 6. A waste liquid hole 8a for discharging the polishing liquid is formed on the lower wall of the polishing liquid receiver 8.

On the other hand, the polishing head 2 is arranged so as to face the rotary table 6. The polishing head 2 is moved by the x-direction feed mechanism 9 and the z-direction feed mechanism 10 in the x-direction and the z-direction.
It is connected to the output shaft of a head rotation motor 12 fixed to a head support member 11 movably provided in the direction, and is rotated in the θz direction by the head rotation motor 12. The size of the polishing head 2 is sufficiently smaller than the size of the polishing surface of the stamper 4, and the polishing cloth 1 (for example, "Surfin018" manufactured by Fujimi Co., Ltd.) is provided on the surface facing the rotary table 6 and the polishing table 2. ) Is attached. Further, the head support member 11 is provided with a polishing liquid supply nozzle 3 connected to a polishing liquid supply source 15 for supplying the polishing liquid to the back surface of the stamper 4 near the polishing cloth 1 during polishing. As the polishing liquid, for example, "POLIPLA-700" manufactured by Fujimi Co., Ltd. is used. Further, the head support member 11 has a polishing head 2 for polishing.
There is provided a pressure detecting means 13 for detecting the pressure applied to the polishing head 4 by contacting the stamper 4.

The control means is 14, a table rotation motor 7,
It controls the drive of the head rotation motor 12, the x-direction feed mechanism 9, and the z-direction feed mechanism 10, and also controls the amount of polishing liquid supplied from the polishing liquid supply source 15 to the polishing liquid supply nozzle 3, and is a sequencer or a personal computer. A computer or the like is used. Further, the detection result from the pressure detection means 13 is sent to the control means 14, and the control means 14 controls the z-direction feed mechanism 10 so that the pressure applied to the polishing head 2 during polishing becomes constant.

Next, the operation of the stamper back surface polishing apparatus of this embodiment will be described.

First, the glass master 5 is placed on the rotary table 6.
The stamper 4 still in close contact with the glass master 5 is placed with the glass master 5 facing downward, and the rotary table motor 7 rotates the rotary table 6 in a direction opposite to the rotary table 6 at a predetermined rotation speed. Next, the head rotating motor 12 rotates the polishing head 2 at a predetermined number of rotations, the polishing liquid supply nozzle 3 supplies the polishing liquid, and the z-direction feeding mechanism 10 lowers the polishing head 2 to lower the polishing cloth 1 and the stamper 4. And contact the back surface of the sheet with a predetermined pressure. Then, the x-direction feed mechanism 9
Thus, the back surface of the stamper 4 is polished by reciprocating the polishing head 2 in the x direction at a predetermined speed.

At this time, the control means 14 controls the pressure detecting means 1
According to the detection result from 3, the z-direction feed mechanism 10 is controlled so that the pressure applied to the polishing head 2 becomes constant, so that the polishing head 2 moves in the z direction along the back surface shape of the stamper 4.
It reciprocates in the x direction while moving in the direction. On the other hand, since the stamper 4 is formed by laminating the conductive film 4a and the electroformed film 4b as described above, the thickness thereof is constant, and the back surface shape of the stamper 4 depends on the surface shape of the glass master 5.
That is, when the glass master 5 is warped or the like, the back surface of the stamper 4 is also warped. Therefore, by polishing the back surface of the stamper 4 while the polishing head 2 moves in the z direction along the back surface shape of the stamper 4, the thickness of the polished stamper 4 becomes constant.

Moreover, the type of polishing is so-called mechanochemical polishing, in which a polishing liquid is supplied between the stamper 4 and the polishing cloth 1 to combine a chemical etching effect and mechanical polishing with polishing particles. Therefore, there are few scratches on the back surface of the stamper 4 due to the abrasive particles, and the back surface of the stamper 4 can be mirror-finished with the same surface accuracy as that of the conventional lapping and polishing apparatus. Further, since the polishing head 2 for polishing the back surface of the stamper 4 is sufficiently smaller than the size of the stamper, the stamper back surface polishing apparatus can be downsized.

The polished stamper 4 has a rotary table 6
Then, it is peeled off at the interface with the resin layer 5b of the glass master 5 and used for manufacturing an optical recording medium. The stamper 4 peeled off from the glass master 5 has a smooth back surface.

In this embodiment, the pressure detecting means 13 is used to move the polishing head 2 along the shape of the back surface of the stamper 4, but the present invention is not limited to this. The shape may be detected by an optical detecting means, and the polishing head 2 may be controlled based on the detection result.

[0023]

Since the present invention is configured as described above, it has the following effects.

In the stamper manufacturing method of the present invention, when the back surface of the stamper is polished, a polishing liquid is supplied between the polishing cloth and the back surface of the stamper, whereby the back surface of the stamper can be finished to a mirror surface with less scratches. . Further, since a polishing head that is smaller than the size of the back surface of the stamper is used and this polishing head is moved along the shape of the back surface of the stamper, the stamper has a constant thickness even if the glass master disc is warped or the like. It can be ground to produce a smooth stamper.

In addition to the effects described above, the stamper back surface polishing apparatus of the present invention uses a polishing head that is smaller than the stamper size, so that the apparatus can be downsized.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a stamper back surface polishing apparatus of the present invention.

FIG. 2 is a cross-sectional view of the stamper and the glass master shown in FIG.

[Explanation of symbols]

 1 polishing cloth 2 polishing head 3 polishing liquid supply nozzle 4 stamper 4a conductive film 4b electroformed film 5 glass master 5a glass substrate 5b resin layer 6 rotary table 7 table rotation motor 8 polishing liquid receiver 8a waste liquid hole 9 x direction feed mechanism 10 z Direction feed mechanism 11 Head support member 12 Head rotation motor 13 Pressure detection means 14 Control means 15 Polishing liquid supply source

Claims (4)

[Claims] 1. A conductive film and an electroformed film are sequentially laminated on a surface of a master on which a concavo-convex pattern corresponding to information to be recorded is formed, whereby the electroformed film and the electroformed film are formed. A stamper for forming an optical recording medium by forming a stamper having a back surface as the back surface, and polishing the back surface of the stamper, and then peeling the stamper at the interface between the master and the conductive film. When polishing the back surface of the stamper, a polishing head having a size smaller than the size of the back surface of the stamper and having a polishing cloth fixed to the surface facing the back surface of the stamper is used, while rotating the polishing head. While reciprocating in the radial direction of the stamper along the shape of the back surface of the stamper, a polishing liquid is supplied between the polishing cloth and the back surface of the stamper to polish the back surface of the stamper. Method of manufacturing a stamper, characterized in that. 2. The position of the polishing head is controlled so that the pressure applied to the polishing head becomes constant by bringing the polishing cloth into contact with the back surface of the stamper, so that the polishing head moves on the back surface of the stamper. The stamper manufacturing method according to claim 1, wherein the stamper is moved along a shape. 3. A conductive film and an electroformed film, which are formed by sequentially laminating a conductive film and an electroformed film on a surface of a master on which an uneven pattern corresponding to information to be recorded is formed. A stamper for forming an optical recording medium having an electroformed film as a back surface is mounted on the master in a state of being in close contact with the master, and is rotatably provided on the rotary table. A polishing head that is provided so as to be reciprocally movable in the radial direction, is smaller than the size of the back surface of the stamper, and has a polishing cloth fixed to the surface facing the back surface of the stamper mounted on the rotary table; Polishing liquid supply means for supplying a polishing liquid between a polishing head and the back surface of the stamper; and during polishing of the back surface of the stamper, the polishing head reciprocates in the radial direction of the stamper, and the polishing A stamper back surface polishing apparatus comprising: a driving unit that moves the head along the shape of the back surface of the stamper. 4. The pressure detecting means for detecting the pressure applied to the polishing head when the polishing cloth contacts the back surface of the stamper, and the pressure detected by the pressure detecting means is constant. 4. The stamper back surface polishing apparatus according to claim 3, further comprising a control unit that controls the position of the polishing head.