JP2009136935A - Polishing pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein a circumferential velocity difference between an inner circumference part and the outer circumference part of a carrier causes an accuracy difference in the surface roughness, parallelism and flatness in a single work in a conventionally used polishing pad whose diameter of openings on the surface is same and whose carrier of a planetary gear type polishing device executes circular movement of autorotation and revolution. <P>SOLUTION: The polishing pad is formed into a doughnut-like shape and changes the opening diameters so as to reduce the dispersion of the surface roughness of the polishing surfaces of the outer circumference part and the inner circumference part and uniformize the accuracy of the parallelism and the flatness, thereby improving the manufacturing efficiency. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polishing pad used in a polishing apparatus that performs mirror polishing of various substrates such as semiconductors such as silicon and gallium arsenide, glass, and metal.

  Conventionally, a planetary gear type plane polishing apparatus for polishing a glass plate, a silicon wafer or the like includes an upper plate, a lower plate, a carrier, a sun gear, and an internal gear. Uses a suede-type abrasive cloth with a microporous urethane resin layer formed on one side of a nonwoven fabric by wet coagulation on the processed surface of the upper and lower plates with a double-sided adhesive tape. To do.

Also, to improve the performance of the polishing pad, the polishing cloth or the polishing surface of the polishing pad is re-polished to improve the surface condition, the surface is grooved by mechanical processing, or a pad with many long pores. To be done.
JP-A-11-77518 JP-A-11-285963 JP2000-42901

  In the case of a planetary gear type plane polishing apparatus that polishes an object to be polished in batch mode, it is mounted on a carrier and several tens of sheets are simultaneously polished. The uniformity of accuracy within a batch of one carrier such as fineness of polishing surface, parallelism / flatness, etc. has been demanded in recent years. There will be a difference in accuracy between the surface roughness and parallel / flatness of the workpiece.

  The present invention provides a polishing pad that meets the demand for higher accuracy after workpiece polishing and aims to improve the accuracy and shorten the production process.

  In order to solve the above problems, the present invention is a suede-like polishing pad that is used by being attached to a polishing plate, and is a polishing pad that is formed by changing the opening diameter in a donut shape. Provided is a polishing pad formed by changing the opening diameter of five donut-shaped bands to 0.1 to 10 times.

  The polishing pad is a suede type polishing cloth in which a urethane resin layer having a microporous structure is formed on one side by a wet coagulation method. In the polishing cloth, a microporous structure generated by a wet coagulation method is formed in a rough shape from the surface to the inside, and the opening diameter appears by grinding with sanding paper from the surface.

  By changing the grinding amount, the opening diameter can also be changed. If the grinding amount is increased, the opening diameter is increased. Based on this principle, it is formed in a donut shape by changing the opening diameter, and 2 to 5 donut-shaped bands are formed. The polishing pad in which the opening diameters adjacent to the doughnut-shaped band are changed to 1.5 to 10 times or 1/10 to 1 / 1.5 times is an object.

  As the nonwoven fabric used for the suede type polishing cloth used in the present invention, a known nonwoven fabric in which a web such as polyester fiber is impregnated with a resin such as synthetic rubber or polyurethane can be used. The suede layer can be produced by a known wet manufacturing method using polyester polyurethane, polyether polyurethane, polycarbonate or the like. Various additives such as pigments can be mixed in the urethane layer.

  Furthermore, a suede type polishing cloth is usually used by attaching a double-sided tape to the back of a non-woven fabric and attaching it to a polishing machine.

Polyester polyurethane resin (solid content 30%) 100 parts, dimethylformamide (DMF) 50 parts, black pigment (pigment content 8%) 30 parts on 1.00 mm thick polyester fiber nonwoven fabric impregnated with 30% polyurethane resin The solution prepared with 1.5 parts of a coagulation accelerator was coated at an application amount of 11100 g / m ² , entered into a 10% DMF aqueous solution coagulation layer, coagulated, washed, and dried. A suede fabric with a foamed structure is obtained.

Usually, at this stage, the surface is ground with sanding paper to make a hole with the desired opening diameter on the surface of the suede layer. In the present invention, the above-mentioned raw cloth is cut into 1300 mm square, and a 125 μm polyester film is cut into a 500 mm diameter. And a doughnut-shaped disk with an inner diameter of 1000 mm and an outer diameter of 1250 mm with Thomson, and center them on a non-woven fabric on the back of the raw cloth cut to 1300 mm, and paste it with an adhesive. Acrylic double-sided tape was applied on the back of the nonwoven fabric. Then, it was ground from a 185 μm suede surface using # 120 paper by a polishing machine. The obtained suede type polishing cloth had opening diameters of 80, 30, and 80 μm from the inside. Further, it was extracted with 1200 mmφ with Thomson, and a single polishing pad was obtained.
To measure the aperture diameter, use a microscope to create standard sample photographs in 9 steps from 20 to 100 μm in increments of 10 μm at a constant magnification, and create measurement materials at the same magnification and compare them with the standard sample. To measure.
Further, the obtained pad can be subjected to drilling, grooving and the like as usual.

  It is also possible to grind the suede cloth in advance to an opening diameter of 30 and 80 μm, and to cut it out separately in a donut shape with Thomson and attach the double-sided tape on the back side.

  The polishing pad of the present invention was attached to a planetary gear type flat polishing apparatus, and final polishing of 2.5 inch glass disks was performed 10 batches by 20 batches. As a result, there was little variation in surface roughness, parallelism and flatness, the rework rate was reduced by 20% compared to the apparatus not using the polishing pad of the present invention, and the process was shortened.

The polishing pad of the present invention has a thickness of 700 μm and a cross section of a suede layer. It is explanatory drawing which showed an example of embodiment of this invention and stuck the polishing pad on the polishing plate, and was seen from the state of a workpiece | work and a carrier right above. It is sectional drawing which affixed the polishing pad of this invention on the polishing plate.

Explanation of symbols

10 Polishing plate 11 Workpiece 12 Carrier 13 Polishing pad 13A Opening diameter 80 μm
13B Opening diameter 30μm

Claims (3)

A polishing pad for polishing a workpiece,
A suede-like polishing pad that is used by being affixed to a polishing plate of a polishing apparatus, and is formed by changing the opening diameter in a donut shape. 2. The polishing pad according to claim 1, wherein the opening diameter between adjacent donut-shaped bands is changed to 1.5 to 10 times or 1/10 to 1 / 1.5 times. The polishing pad according to claim 1, wherein 2 to 5 donut-shaped bands are formed.

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