Polishing pad
AssigneeRohm and Haas Electronic Materials CMP Holdings, Inc.
InventorHiroshi Seyanagi
Life of this patent
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Abstract
A polishing pad has a polishing layer that is formed of a polyurethane foam having fine cells. The polyurethane foam is a reaction cured body of a chain extender and an isocyanate-terminated prepolymer which is obtained by reacting a prepolymer starting material composition that contains an isocyanate component, a high molecular weight polyol and an aliphatic diol. The high molecular weight polyol contains a polyalkylene glycol A that has a peak of the molecular weight distribution within the range of 200 to 300 and a polyalkylene glycol B that has a peak of the molecular weight distribution within the range of 800 to 1200.
Claims6
A method for producing a polishing pad, comprising the steps of:
- (C) synthesizing an isocyanate-terminated prepolymer and
- (D) mixing a first component containing the isocyanate-terminated prepolymer with a second component containing a chain extender and curing the mixture to prepare a polyurethane foam, wherein:
- the step (C) comprises reacting an isocyanate component with an aliphatic diol and a polyalkylene glycol A that has number average molecular weight within the range of 200 to 300 to synthesize a prepolymer precursor and then reacting the prepolymer precursor with a polyalkylene glycol B that has a number average molecular weight within the range of 800 to 1200 to synthesize the isocyanate-terminated prepolymer, and
- the step (D) comprises adding 3 to 10 parts by weight of a silicone-based surfactant based on 100 parts by weight of the isocyanate-terminated prepolymer, to the first component containing the isocyanate-terminated prepolymer, further stirring the first component together with a non-reactive gas to form a cell dispersion liquid in which the non-reactive gas is dispersed in the form of fine cells, then mixing the second component containing the chain extender into the cell dispersion liquid, and curing the mixture to prepare a polyurethane foam.
Dependencies are inferred from the claim text.