Patent ID: 6443826
Filing Date: 2002-09-03
Classification: B24B

Abstract:
A retainer ring of a polishing head of a chemical mechanical polishing apparatus, the retainer ring comprising:an annular ring body having a radially innermost peripheral surface, a radially outermost peripheral surface, and at least six contaminant outlets extending between and open to said radially innermost and radially outermost peripheral surfaces of the ring body for exhausting contaminants induced into an inner space of the polishing head, said contaminant outlets being spaced apart from one another in a circumferential direction of the ring body at substantially equal angular intervals, and a sum of widths of the contaminant outlets as taken at said radially innermost peripheral surface in the circumferential direction thereof being at least 30% of a circumference of said radially innermost peripheral surface, and said ring body having a top surface and a plurality of threaded holes extending into said top surface for receiving screws which fix the retainer ring in place in the polishing head, the contaminant outlets being offset from the threaded holes in the circumferential direction of the ring body.