JPH0557622A - Abrasive cloth - Google Patents

Abstract

PURPOSE:To provide an abrasive cloth with which generation of deterioration of surface roughness, injury, or the like are not caused and roll-over of the end face can be restrained when a workpiece to be polished is polished. CONSTITUTION:A target is an abrasive cloth in which a surface layer 2 for polishing is laminated on the surface of a base layer 1 made of nonwoven fabric. Hardness of the base layer 1 is prescribed to be over hardness 80 deg. by the spring type hardness test model C indicated in JIS K 6301.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing cloth used for polishing aluminum (including alloys thereof) magnetic disk substrates, semiconductor wafers, optical component lenses, wafer masks, metal samples and the like.

[0002]

2. Description of the Related Art The above-described polishing process for a product to be polished is performed, for example, as follows. That is, using a polishing machine in which a polishing cloth is adhered to the upper and lower surface plates of a horizontal double-sided polishing machine,
The upper and lower surface plates are pressed with a constant pressure to bring the polishing cloth and the workpiece to be pressed into contact with each other. Then, after supplying the loose abrasive grains, the upper and lower surface plates and the workpiece to be polished are rotated to slide the polishing cloth and the workpiece to polish the surface of the workpiece.

As shown in FIG. 4, generally, a polishing cloth used for the polishing process as described above has a porous polishing surface made of polyurethane or the like on the surface of a base layer (51) made of a nonwoven fabric such as polyester fiber. The layer (52) is integrally formed on the back surface of the base layer (51), and the surface plate (60) is formed on the back surface of the base layer (51).
It has a structure coated with an adhesive layer (53) for adhering to the.

[0004]

By the way, recently, with the demand for miniaturization and high precision of the workpiece to be polished, strict surface characteristics after polishing have been required.

However, when the conventional polishing cloth is used for polishing, as shown in FIG. 4, the portion of the polishing cloth (50) that comes into contact with the workpiece (70) to be polished is largely compressed and deformed due to its elasticity. As a result, the step between the deformed portion (54) and the non-deformed portion (55) becomes large, so that the workpiece to be polished (70) located at the boundary between the deformed portion (54) and the non-deformed portion (55). The surface of the polishing pad is in contact with the edge portion in a curved shape. When polishing is performed in such a state, a large pressing force is applied diagonally to the edge portion of the workpiece (70), so that the edge portion is polished in a slanted or arcuate shape, so-called end face sag (71 ) Was caused.

For this reason, it has been attempted to suppress the amount of compressive deformation of the polishing cloth as much as possible by impregnating the surface layer (52) of the polishing cloth (50) with a curing agent, thereby suppressing the sagging of the end surface. There is.

However, in this method, if the degree of hardening treatment is too severe, the surface roughness of the article to be polished (70) may be lowered, or the surface may be scratched or scratched. It was a new problem that the good surface condition of could not be obtained. For this reason,
There is a limit to the curing treatment of the surface layer, and it is not possible to reliably and sufficiently suppress the sagging of the end surface.

The present invention has been made in view of the above technical background, and it is possible to suppress the sagging of the end surface without causing a decrease in the surface roughness or the occurrence of scratches or the like during the polishing process for the workpiece to be polished. The purpose is to provide a polishing cloth.

[0009]

In order to achieve the above object, the present invention aims to reduce the amount of compressive deformation of the polishing cloth during polishing by increasing the hardness of the base layer, not the surface layer. Is.

That is, referring to the reference numeral in FIG. 1, the present invention provides a polishing cloth in which a polishing surface layer (2) is laminated on the surface of a base layer (1) made of a non-woven fabric. ) Is defined to have a hardness of 80 ° or more in the spring hardness test C type shown in JIS K6301.

[0011]

The base layer (1) is defined to have a hardness of 80 ° or more in the spring hardness test C type shown in JIS K6301, so that the amount of compressive deformation when it is pressed against a workpiece to be polished during polishing is small. Therefore, the step between the deformed portion and the non-deformed portion becomes smaller. Therefore, the pressing force applied from the polishing cloth to the edge portion of the workpiece to be polished located at the boundary between the deformed portion and the non-deformed portion of the polishing cloth is reduced, and as a result, the end face sagging is suppressed.

[0012]

Embodiments of the present invention will be described below.

FIG. 1 shows a polishing cloth (A) according to an embodiment of the present invention. In FIG. 1, (1) is a base layer made of polyester fiber non-woven fabric, and (2) is a polyurethane polishing surface layer integrally formed on the surface of the base layer (1). The layer (2) is made porous so as to retain loose abrasive grains supplied during the polishing process. The back surface of the base layer (1) is treated with a primer, and an adhesive layer (3) made of a double-sided tape is formed on the back surface, and the polishing cloth (A) is fixed through the adhesive layer (3). It is supposed to be able to adhere to the board.

In the present invention, the base layer (1) is J
Spring hardness test C specified in IS K6301
It must be made to have a hardness of 80 ° or greater in shape. The spring hardness test C type specified in JIS K6301 is, as a rule, a test piece having a thickness of 6 mm or more (those with a thickness of less than 6 mm should be stacked to have a thickness of 6 mm or more). The hardness measurement test is carried out by using the C type, which is originally a test for measuring the hardness of the vulcanized rubber, but in the present invention, this is applied mutatis mutandis to the hardness test of the base layer (1). Here, the hardness of the base layer (1) is defined to be 80 ° or more in the above test,
This is because if the hardness is less than 80 °, the sagging of the end face cannot be sufficiently suppressed.

That is, when the hardness is less than 80 °, the base layer is too soft and the amount of compressive deformation when pressed against the workpiece to be polished during polishing is too large, resulting in a large step between the deformed portion and the non-deformed portion. Therefore, a large pressing force is applied obliquely to the entire edge portion of the workpiece to be polished located at the boundary between the deformed portion and the non-deformed portion of the polishing cloth, and as a result, the occurrence of end face sagging can be suppressed. Because there is no. Conversely,
By setting the hardness of the base layer (1) to 80 ° or more,
The difference in the amount of deformation between the compressed and non-deformed portion of the polishing cloth can be reduced, the pressing force applied to the edge portion from the polishing cloth can be reduced, and as a result, the occurrence of end face sagging can be suppressed. Because you get it. Particularly preferably, the hardness of the base layer (1) is set to 90 ° or more in the above test.

The means for defining the base layer (1) to have a hardness of 80 ° or more is not particularly limited. For example, the base layer may be formed of a hard non-woven fabric, the density of the non-woven fabric may be increased, or the softness of the non-woven fabric may be increased. A method of impregnating the base layer with a curing agent may be mentioned.

By the way, the thickness of the base layer (1) is 1 mm,
The thickness of the surface layer (2) is set to 0.5 mm, and only the hardness of the base layer (1) is 75 in the spring hardness test C type specified in JIS K6301.
The occurrence of edge sagging was examined using three types of polishing cloths defined at 80 °, 90 °, and 80 °.

As a test piece, as shown in FIG. 2, an aluminum magnetic disk substrate (diameter L1: 95 mm, diameter L2 excluding the outer chamfer portion (11): 94.7 mm, and thickness t: 1.27 mm ( 10) is used to set the sag measuring portion (12) from the inner end edge of the outer chamfer portion (11) to the inside L3: 4 mm, and the height difference H ( (Shown in FIG. 3) was measured as the amount of sag. The results are shown in Table 1.

[0019]

[Table 1]

As can be seen from Table 1 above, by setting the hardness of the base portion (1) to 80 ° or more in the spring hardness test C type specified in JIS K6301, the sagging of the end surface of the workpiece to be polished is significantly increased. It was confirmed that it can be suppressed.

[0021]

As described above, according to the present invention, in a polishing cloth in which a polishing surface layer is laminated on the surface of a base layer made of a non-woven fabric, the base layer is in a spring hardness test C type specified in JIS K6301. Since the hardness is specified to be 80 ° or more, the amount of compressive deformation of the polishing cloth at the time of polishing can be reduced, and consequently the end face sagging of the edge portion of the polishing product can be suppressed. Moreover,
Rather than increasing the hardness of the surface layer, it increases the hardness of the base layer that does not come into direct contact with the surface of the work piece, which may cause a decrease in surface roughness or scratches on the work piece. It is possible to provide a high-quality polished product by suppressing edge sagging of the edge portion while maintaining good surface polishing condition.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a polishing cloth according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of an aluminum magnetic disk substrate as a workpiece to be polished used in a test for confirming the effect of the present invention.

FIG. 3 is an enlarged sectional view of an essential part of an aluminum magnetic disk substrate after polishing.

FIG. 4 is a cross-sectional view of essential parts showing a state in which a polishing process is performed using a conventional polishing cloth.

[Explanation of symbols]

 A ... Polishing cloth 1 ... Base layer 2 ... Surface layer

Claims (1)

[Claims] 1. A polishing cloth in which a polishing surface layer (2) is laminated on the surface of a base layer (1) made of a non-woven fabric, wherein the base layer (1) is a spring hardness test C type specified in JIS K6301. The hardness of the polishing cloth is 80 ° or more.