Speedfam-Ipec Corporation

Novellus Systems Incorporated

Guangying Zhang

Thomas Laursen

Sumit Guha

A method and apparatus for 'through-the-pad' delivery of slurry polishing agents directly to the land areas of a polishing pad is disclosed. The present invention further provides for improved control of the chemical composition of the slurry to address loss of chemical reactivity of the slurry during the polishing cycle. Additionally, various groove modifications to the polishing surface of the pad are also disclosed for improved slurry retention over substantially the entire surface of the polishing pad and reduction of the slow band effect. The present invention thus provides for a higher degree of planarization and uniformity of material removed from the surface of a processed workpiece in order to eliminate, or otherwise reduce, small-scale roughness and large-scale topographic differentials as well as to reduce the Cost-of-Ownership associated with slurry costs.

Method and apparatus for controlled slurry distribution

Method and apparatus for controlling slurry distribution

A single-layer polishing pad is grooved in a pattern having relatively large turn radius bends (i.e., greater than the 90&deg; bends of conventional rectangular grid grooving) to improve stability. The large radius bends allow slurry to be more easily and uniformly distributed across the surface of the polishing pad than conventional rectangular grooving. This improvement in slurry distribution tends to improve RR uniformity and WIWNU. In one embodiment, the polishing pad is grooved in a hexagonal pattern, which produces a grooving pattern with 120&deg; bends. The grooves do not penetrate all of the way through the upper layer, thereby maintaining the &ldquo;stiffness&rdquo; of the polishing pad, which tends to improve planarization. When used in conjunction with standard pad conditioning techniques, polishing pads with groove patterns having large radius bends has yielded startling and unexpected improvement in stability. The improved fluid distribution provided by the groove pattern is believed to allow the pad conditioning process to clean the polishing pad of residual slurry, polishing debris and polishing by-products more thoroughly than polishing pads with conventional rectangular groove patterns.

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Chandler, AZ, United States of America

Guangying Zhang