Patent ID: 8845852
Filing Date: 2014-09-30
Classification: B24B

Abstract:
1. An apparatus for chemical mechanical polishing in combination with a polishing pad and material to be polished, comprising said material to be polished and the polishing pad used in chemical mechanical polishing and having a polishing region and a light-transmitting region, said polishing pad having the following characteristics: i) light transmittance in the light-transmitting region throughout the wavelength range of 400 to 700 nm is 70% or more; and ii) a thickness of the light-transmitting region is 0.5 to 4 mm, and light transmittance in the light-transmitting region throughout the wavelength range of 500 to 700 nm is 90% or more; wherein the light-transmitting region is arranged between a central portion and a peripheral portion of the polishing pad, and a length (D) of the light transmitting region in a diametrical direction is 3 times or more longer than a length (L) in a circumferential direction, wherein a length (D) in a diametrical direction is ¼ to ½ relative to the diameter of a material to be polished, and a scatter of the thickness of the light-transmitting region is 100 μm or less wherein materials for forming the polishing region and the light-transmitting region are polyurethane resin, and the polyurethane resin as the material for forming the polishing region and the polyurethane resin as the material for forming the light-transmitting region are different materials but produced from the same kinds of organic isocyanate, polyol and chain extender, and wherein the polyurethane resin as the material for forming the light-transmitting region does not contain aromatic polyamine and the material for forming the light transmitting region is non-foam, wherein a material for forming the polishing region is fine-cell foam, and wherein a rate of change of the light transmittance in the light-transmitting region in wavelengths of 400 to 700 nm represented by the following equation is 30% or less: