JP3453662B2 - Polishing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for polishing a disk-shaped substrate having a non-polishing target surface in the center.

[0002]

2. Description of the Related Art Polishing of optical components such as flat plates and lenses has been performed for a long time, and polishing is performed by using a polishing plate such as a pitch plate or a pad plate and an abrasive such as cerium oxide. .

In these polishings, while polishing the substrate surface and the polishing plate relative to each other, a polishing agent suspended in water is supplied between the polishing surface of the polishing plate and the substrate surface for polishing. Specifically, if you capture a moment, if you supply an abrasive to the exposed substrate surface without being covered with a polishing dish, that surface will eventually be polished and the abrasive will spread to the substrate surface, eventually Will polish the entire surface of the substrate to be polished.

[0004]

However, the entire surface of the substrate is not the surface to be polished, and there may be a surface that should not be polished, a surface that should not be polished, or a surface that cannot be polished. As an example of this, there is a disk-shaped substrate having a through hole in the central portion. When it is attempted to polish the entire surface of such a donut disk-shaped substrate in the conventional manner, the uniformity of polishing in the vicinity of the central through hole is lacking. Further, when the periphery of the central through hole is projected with a step like a CD disk (compact disk), this protruding portion becomes an obstacle, and it is not possible to polish the surface substrate of the recording layer which is one step lower than the outer peripheral portion. It's extremely difficult.

[0005]

The inventors of the present invention have made extensive studies on a method for polishing a disk-shaped substrate having a non-polishing target surface in the center such as the donut disk-shaped substrate as described above, and as a result, a polishing plate. By providing a concave portion that does not form a polishing surface, and storing the non-polishing target surface in this concave portion and polishing the storage target surface with the polishing surface without polishing the storage area, the above disadvantage is eliminated and the polishing is performed. I found something to say.

That is, according to the polishing method of the present invention, a liquid polishing agent is supplied between the surface of a disk-shaped substrate to be polished having a non-polishing target surface in the center and the polishing surface of a polishing dish, and the substrate is polished. While rotating, the polishing dish is reciprocated in the surface direction of the substrate so that a part of the polishing target surface of the substrate is exposed on the outer peripheral side of the polishing dish, and when polishing the substrate with an abrasive,

As a polishing plate, a polishing plate having a recess that does not form a polishing surface is used. With the non-polishing target surface housed in the recess, the outer periphery of the polishing plate is polished without polishing the non-polishing target surface. A polishing agent is supplied to the surface to be polished exposed to the side to polish the entire surface to be polished.

The above-described polishing method is also effective when the through hole is formed in the center or when the center portion projects from the surface to be polished so as to form a step. By storing it in the concave part of and polishing
The surface to be polished can be polished without being disturbed by the protruding step portion.

Further, since the polishing plate can be reciprocated only within the range where the non-polishing target surface is accommodated in the recess of the polishing plate, the movement stroke length of the polishing plate tends to be short, and the polishing plate during polishing tends to be short. The area of the substrate exposed from the area becomes small, and the supply of the abrasive tends to be insufficient. Therefore, in the present invention, in addition to supplying the polishing agent to the exposed portion of the substrate from the polishing dish, it is desirable to provide a through hole in the recess of the polishing dish and supply the polishing agent solution to the substrate surface through the through hole. Since there is a gap between the surface of the substrate and the opening of the through hole, the abrasive liquid is smoothly supplied to the surface of the substrate.

[0010]

EXAMPLE FIG. 1 is an explanatory view showing an example of the polishing method of the present invention. 2 is an exploded perspective view of FIG.
However, the polishing jig is shown from the release side, and the one in the proper position is shown by an imaginary line in the perspective view. Further, the abrasive supply nozzle 53 is not shown.

The substrate 11 (substrate to be polished) is set on the holder setting portion 21a of the rotatable substrate holder 21. The substrate 11 has a flat plate type donut disk shape as a whole, has a through hole 11b in the central portion, and a step portion 11a protruding around the through hole 11b, and a flat portion occupying most of the surface area through the tapered portion. It is connected to 11c. Of this surface portion, the through hole 11b, the step portion 11a, the taper portion, and the flat portion 11c in the immediate vicinity of the taper portion are non-polishing target surfaces,
Most of the remaining flat portion 11c is the surface to be polished.

The material of the substrate 11 includes glass such as optical glass, plastic such as polycarbonate and acrylic resin, but is not particularly limited. Further, the shape of the substrate to be polished by the present invention is not limited to that shown in the drawing, and for example, the flat portion 1 without the step portion 11a is present.
It may be a typical donut-shaped disc composed of 1c and a through hole 11b, in which the through hole 11b does not exist and the step portion 11a is formed.
Only, or the central portion may be a non-polishing target surface for some reason without having both the step portion 11a and the through hole 11b, and both surfaces or one surface may be spherical or aspherical. .

On the substrate 11, a polishing jig 31 (polishing plate) is placed. The polishing jig 31 has a jig-side engaging hole 31b for receiving a driving force from the drive shaft 41 on its upper surface, while the lower surface side forms a polishing surface except for a part thereof.
On the lower surface side of the polishing jig 31, there is a recess 31a in the center thereof, and a polishing pad 33 made of polyurethane or the like is fixed to the portion excluding the recess 31a. Note that FIG.
In the embodiment shown in FIG. 2, the central portion of the lower surface of the polishing jig 31 itself is engraved to form the recess 31a. However, the lower surface of the polishing jig 31 itself has a shape that matches the surface curvature of the substrate, and the polishing pad 33 is used. Alternatively, a ring-shaped one may be used as the concave portion of the polishing plate depending on the thickness of the polishing pad 33.

The recess 31a of the polishing jig 31 has a through hole 31c which is open from the upper surface to the lower surface of the polishing jig 31 toward the front surface of the substrate 11. Drive shaft 4 for polishing
The shaft side engaging rod 41a of No. 1 is fitted into the jig side engaging hole 31b, and while supplying the abrasive liquid 53 from the abrasive liquid supply nozzle 51, the substrate holder 21 is rotated by the holder rotating shaft 21a, while The drive shaft 41 is reciprocated along the surface direction of the substrate 11. The polishing jig 31 includes the shaft side engaging rod 3
Since the surroundings of 1b are rotatably engaged and connected to the drive shaft 41, the rotational force of the substrate holder 21 is transmitted by friction while being transferred in the diameter direction of the substrate 11 by the drive shaft 41, and the polishing jig is then transferred. 31 is rotated, and the surface of the substrate 11 is polished by the polishing pad 33 and the polishing agent liquid 53.

The non-polishing target surface centering on the through hole 11b and the stepped portion 11a of the substrate 11 is the recess 31 of the polishing jig 31.
The non-polishing target surface can be always positioned in the jig concave portion 31a by adjusting the stroke length of the reciprocating motion of the drive shaft 41 housed in a, and the non-polishing target surface is polished by the polishing pad. Never.

The polishing agent liquid 53 is supplied to the surface of the substrate 11 which is not covered with the polishing jig 31 (area A in FIG. 1) and is used for polishing by the polishing pad 33. Also,
Further, in the embodiment shown in FIGS. 1 and 2, the polishing agent liquid 53 is supplied to the surface of the substrate 11 from the through holes 31c of the polishing jig 31. Since the opening surface of the through hole 31c and the surface of the substrate 11 are not in close contact with each other and have a sufficient gap, the polishing agent liquid 53 is smoothly supplied to the surface of the substrate 11.

In polishing the disk-shaped substrate 11 having the non-polishing target surface in the center, it is necessary to polish the disc-shaped substrate 11 so that the non-polishing target surface is always housed in the jig recess 31a. The stroke length of the drive shaft 41 moving in the direction is naturally limited, and therefore, the abrasive liquid 53
In some cases, the area of the region A to which is supplied is limited, and it may be difficult to supply the sufficient polishing agent liquid 53. On the other hand, Figs.
In the embodiment shown in (1), since the polishing agent liquid 53 is also supplied from the through holes 31c, it is possible to supply the polishing agent solution 53 to the surface of the substrate 11 sufficiently, which shortens the polishing time and further improves the polishing quality. It will be possible.

In the present invention, the substrate 11 to be polished is used.
The type, the material, the use, etc. of the disc are not limited, but FIGS. 1 and 2 assume a compact disc (CD disc). It is unavoidable that the CD disc will be scratched due to use and handling.
Although this causes noise, the polishing method of the present invention can efficiently polish only the surface to be polished to eliminate the scratches. Further, in the above-described embodiment, the case where the upper surface of the substrate 11 is polished has been shown, but the positional relationship between the substrate holder 21 and the polishing pad 33 is reversed and the substrate 11 is polished.
It is also possible to polish the lower surface of the.

[0019]

According to the present invention as set forth in claim 1, it is possible to efficiently polish a disk-shaped substrate having a non-polishing target surface in the center. Further, according to the present invention as set forth in claim 2, the polishing agent can be efficiently supplied to the surface of the substrate through the through holes provided in the polishing plate, the polishing time can be shortened, and the polishing quality can be further improved. Is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a polishing method of the present invention.

FIG. 2 is an exploded perspective view of FIG.

[Explanation of symbols]

11 board 11a stepped portion 11b through hole 11c Flat part 21 board holder 21a Holder set part 21b Holder rotation axis 31 Polishing jig 31a jig recess 31b Jig side engaging hole 31c through hole 33 polishing pad 41 drive shaft 41a Shaft side engaging rod 51 Abrasive liquid supply nozzle 53 Abrasive liquid

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Claims (2)

(57) [Claims] 1. A liquid abrasive is supplied between the surface of a disk-shaped substrate to be polished having a non-polishing target surface in the center and the polishing surface of a polishing plate, and the substrate is rotated while the polishing plate is removed. When polishing the substrate with an abrasive so that a part of the polishing target surface of the substrate is exposed to the outer peripheral side of the polishing plate by reciprocating in the surface direction of the substrate, the polishing surface does not constitute a polishing plate Using a polishing dish having a concave portion and supplying the polishing agent to the surface to be polished exposed on the outer peripheral side of the polishing dish without polishing the non-polishing target surface while the non-polishing target surface is housed in the concave portion A method for polishing a disk-shaped substrate, characterized by polishing the entire surface to be polished. 2. A through hole is provided in the recess of the polishing plate,
The polishing method according to claim 1, wherein the polishing target surface is polished by supplying an abrasive to the substrate surface on the inner peripheral side of the polishing surface through the through holes.