JPH0660442A - Method and device for polishing rear surface of stamper - Google Patents

Abstract

PURPOSE:To provide the method and device for polishing the rear surface of a stamper which can easily and uniformly polish the rear surface of the stamper to a mirror finished surface even if the stamper has warpage, etc., as the method and device for polishing the rear surface of the stamper by peeling the stamper (electrocasting film) for optical disks from a glass substrate. CONSTITUTION:An annular polishing pad 1 is fixed to a turn table 2 concentrically with the center of rotation of the turn table to form an annular space 5. A compressor 10 is connected via a pressure regulating tank 9 to the annular space 5. A protective film is formed on the front surface side of the stamper and the stamper is fixed to a stamper holder 33 of a rotary holder 32 via the protective film. Compressed air is supplied to the annular space 5 at the time of polishing and the rear surface of the warped electrocasting film is polished by specifying the thickness of the compressed air layer to 2 to 3mm, the absolute pressure to 1 to 2 atm and the polishing pressure to 100g/cm<2>.

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 method and a polishing apparatus (mechanochemical polishing apparatus) for manufacturing an optical disk.

[0002]

2. Description of the Related Art Conventionally, in the back surface polishing of a stamper for an optical disk, an electroformed film (electroformed layer) made of Ni or the like is peeled from a glass substrate (glass master), and a paper polishing machine using a belt-shaped emery tape or a water-based abrasive is used. A method of polishing the back surface in the form of a single electroformed film using an apparatus for polishing while supplying grains has been used. However, recently, the abrasive grain size is not changed in the middle, and polishing is performed once (15 to 20 minutes).
The mechanochemical polishing that uses combined processing of abrasive grain polishing and chemical polishing, which can easily obtain a mirror surface (0.1S) state, is often used.

The essence of this mechanochemical polishing is as shown in FIG. 3, in which a stamper holding plate 33 is vacuum-sucked and held by a rotary holder 32 having suction holes 31, and a protective film 35 is applied to the surface of the stamper 34. The surface side is fixed to the stamper holding plate 33 with adhesive tapes 37 and 38 via a soft plate 36. On the other hand, the polishing pad 39 is attached and fixed to a turntable (rotary platen) 41 with an adhesive tape 40. When polishing, the turntable 41 is rotated, the rotary holder 32 is pressed against the turntable 41 in a freely rotating state, and polishing is performed while supplying the mechanochemical polisher liquid.

[0004]

However, the electroformed film (stamper) peeled off from the glass substrate has a complicated warp due to the electrodeposition stress and external force at the time of peeling, if observed in detail, and also partially. There is a difference in plate thickness. For this reason, unevenness in adhesion occurs between the polishing pad and the back surface of the stamper during polishing, and even if the entire back surface of the stamper is mirror-finished in appearance, polishing unevenness occurs in optical inspection such as shadowgraph. Is confirmed. in this way,
The conventional polishing technique has a problem that it is difficult to uniformly mirror-polish the back surface of the stamper in which warpage has occurred.

The present invention has been made in view of the above problems, and an object thereof is to provide a polishing method capable of simply and accurately polishing the back surface of the stamper even if the stamper is warped, and an apparatus therefor. It is what

[0006]

According to the stamper back surface polishing method of the present invention, an electroformed film to be a stamper for an optical disk is formed on a glass substrate, and the electroformed film is peeled from the glass substrate to form a turntable for a polishing machine. In the method of polishing with the polishing pad provided in step 1, the fluid is pressure-controlled and supplied to the facing gap between the turntable and the polishing pad for polishing.

Further, the stamper back surface polishing apparatus of the present invention is
An electroformed film to be a stamper for an optical disc is formed on a glass substrate, and the electroformed film is peeled from the glass substrate and polished by a polishing pad provided on a turntable of a polishing machine. The polishing pad is provided concentrically with the center of rotation of the turntable, and the annular space formed by the polishing pad and the turntable is connected to the fluid pressure regulating tank via the through hole formed in the turntable. The pressure regulating tank is connected to a fluid pressure device.

[0008]

In the stamper back surface polishing method of the present invention, since the gap between the turntable and the polishing pad is filled with the fluid, the fluid filled portion acts as a cushioning material, and when the electroformed film is pressed against the polishing pad. In addition, the polishing pad absorbs the warp or uneven shape of the glass substrate. Therefore, the entire region to be polished on the back surface of the stamper can be brought into close contact with the polishing pad with a uniform pressure, and efficient and uniform polishing can be achieved.

Further, in the stamper back surface polishing apparatus of the present invention, since the annular space formed by the polishing pad and the turntable is filled with the fluid, the back surface of the stamper in which the warp or the like has occurred is exactly as in the polishing method. It can be polished. Further, since the annular space is connected to the fluid pressure control tank and the fluid pressure device, the surface flexibility of the polishing pad can be adjusted, so that the polishing pressure can be easily set to a desired value. . Further, since it becomes possible to bring the entire region to be polished on the back surface of the stamper into close contact with the polishing pad with a uniform pressure, it is possible to uniformly supply the polishing abrasive grains and the reactive substance.

[0010]

The present invention will now be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 shows the entire structure of the polishing machine. An annular polishing pad 1 having a circular hole at its center is placed on the upper surface of a turntable 2 concentrically with its rotation center.
The outer peripheral fixed frame 3 and the inner peripheral fixed frame 4 are fixed, and the polishing pad 1 and the turntable 2 form an annular space 5. A through hole is formed in the turntable 2 and its rotating shaft 6 to form a pressurized fluid supply passage 7, the upper end of the pressurized fluid supply passage 7 is connected to the annular space 5, and the lower end is connected via a pipe 8. The pressure regulating tank 9 and the pressure regulating tank 9 communicates with the compressor 10 (or the liquid pressurizing device). Further, a polishing liquid discharge hole 11 is provided at the center of the turntable 2.
Is connected to the polishing liquid waste tank 13 through a drain pipe 12 provided in the pressurized fluid supply path 7, and a drain receiver 14 surrounding the turntable 2 is provided,
The drain pipe 15 also communicates with the waste liquid tank 13. 1
Reference numeral 6 is a rotation support member for the turntable 2.

When the back surface of the stamper is polished by the polishing machine, as shown in FIG. 2, the front surface side of the stamper 34 is fixed to the stamper holding plate 33 in the same manner as in FIG. Absolute pressure 1-2 at
The compressed air whose pressure is adjusted to m is supplied so that the thickness of the compressed air layer is 2 to 3 mm, and the pressure on the back surface of the stamper 34 is 95 to 130.
It is brought into close contact with the polishing pad 39 with g / cm ² (polishing pressure),
Polishing is performed while supplying a polishing liquid to the surface of the polishing pad 39.

Using this apparatus and the apparatus shown in FIG. 3, a polishing experiment was conducted on a plurality of stampers having the same specifications under the same polishing pressure and other conditions. The entire surface was polished to a mirror surface state, and it was confirmed by optical inspection with a shadowgraph that polishing unevenness hardly occurred.
Although the entire surface of the device of No. 3 was mirror-finished, uneven polishing was detected by the shadow graph.

[0013]

As is apparent from the above description, according to the stamper back surface polishing method and the stamper back surface polishing apparatus of the present invention, the gap between the turntable and the polishing pad is filled with fluid to polish the back surface of the electroformed film. Since the pad is pressed against the surface to be polished, even if there is a warp or the like on the back surface of the electroformed film, the fluid-filled portion deforms in conformity with the warp or the like, and the portion to be polished on the back surface of the electroformed film Since the entire surface is brought into close contact with the polishing pad with a uniform contact pressure, the surface to be polished can be uniformly mirror-polished, and it can be widely applied as various high-precision surface polishing techniques. It should be noted that in both the polishing method and the polishing apparatus of the present invention, the glass substrate is fixed to the rotary holder by a proper member (the peripheral surface is sandwiched) without peeling the electroformed film from the glass substrate, and electroforming is performed. It can also be effectively applied when polishing the back surface of the film.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the device of the present invention.

FIG. 2 is a sectional view of a polishing portion in the embodiment of FIG.

FIG. 3 is a cross-sectional view of a polishing section in a conventional polishing machine.

[Explanation of symbols]

 1 polishing pad 2 turntable 3 outer circumference fixed frame 4 inner circumference fixed frame 5 annular space 6 rotary shaft 7 pressurized fluid supply passage 8 piping 9 pressure adjusting tank 10 compressor 11 discharge hole 12 drainage pipe 13 polishing fluid waste liquid tank 14 Drainage receiver 15 Drain pipe 16 Rotation support member 31 Adsorption hole 32 Rotation holder 33 Stamper holding plate 34 Stamper 35 Protective film 36 Soft plate 37, 38, 40 Adhesive tape 39 Polishing pad 41 Turntable

Claims (2)

[Claims] 1. A method of forming an electroformed film as a stamper for an optical disk on a glass substrate, peeling the electroformed film from the glass substrate and polishing with a polishing pad provided on a turntable of a polishing machine, wherein the turn A backside polishing method for a stamper, characterized in that a fluid is pressure-controlled and supplied to a facing gap between a table and a polishing pad for polishing. 2. A polishing apparatus in which an electroformed film serving as an optical disk stamper is formed on a glass substrate, and the electroformed film is peeled off from the glass substrate and polished by a polishing pad provided on a turntable of a polishing machine. In the above, an annular polishing pad is provided concentrically with the center of rotation of the turntable, and an annular space formed by the polishing pad and the turntable is provided with a fluid pressure adjusting tank through a through hole formed in the turntable. The stamper back surface polishing apparatus, wherein the pressure adjusting tank is connected to a fluid pressurizing device.