Importance

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Abstract

An apparatus and method for conditioning a pad used for chemical-mechanical planarization (CMP) are provided, that allow the conditioning to be performed in situ without stopping the polishing. A retractable pad-conditioning structure, e.g., conditioning tips, is positioned along the bottom perimeter of a wafer carrier. While polishing a surface of a wafer held in the middle of the wafer carrier, whenever the removal rate drops below a permissible value, the pad-conditioning structure, which rotates in unison with the wafer carrier, is lowered to contact the pad to condition the pad's surface. Since an area of the pad used for polishing the wafer is always surrounded by already conditioned pad areas and the area for polishing moves as the wafer carrier moves around on the pad surface, a substantially uniform removal rate is maintained. When the pad is sufficiently conditioned, the conditioning structure is retracted until the pad needs to be conditioned again.

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First Claim