Memc Electronic Materials, Inc.

Giovanni Negri

Ezio Bovio

Paride Corbellini

Henry Frank Erk

Peter D Albrecht

Yun-Biao Xin

Dennis Buese

Luca Moiraghi

Kan-Yin Ng

Stephen Wayne Hensiek

Darrel M Harris

Marco Morganti

James Jose

Gene Hollander

A wafer polishing apparatus for polishing a semiconductor wafer. The polisher comprises a base (), a turntable (), a polishing pad () and a drive mechanism () for driven rotation of a polishing head (). The polishing head is adapted to hold at least one wafer () for engaging a front surface of the wafer with a work surface of the polishing pad. A spherical bearing assembly () mounts the polishing head () on the drive mechanism for pivoting of the polishing head about a gimbal point (p) lying no higher than the work surface when the polishing head holds the wafer in engagement with the polishing pad. This pivoting allowing the plane of the front surface of the wafer to continuously align itself to equalize polishing pressure over the front surface of the wafer, while rotation of the polishing head is driven by the driving mechanism. This maintains the front surface and work surface in a continuously parallel relationship for more uniform polishing of a semiconductor wafer, particularly near the lateral edge of the wafer. A cassette of wafers and method of polishing are also disclosed.

Semiconductor wafer, polishing apparatus and method

The method comprises the steps of mounting a first wafer () on the mounting member () and securing the mounting member to the hub () by drawing a vacuum at a first vacuum pressure through the hub; rotating the hub about the hub axis (AH), rotating a polishing pad () mounted on the turntable () about the turntable axis (at), and bringing a surface of the wafer () and the polishing pad into contact with each other. The wafer () is demounted, and the shape of the polished wafer is determined. A second vacuum pressure is selected using the information obtained. A successive wafer is polished according to the same method as the first wafer except that the second vacuum pressure is substituted for the first vacuum pressure. The second vacuum pressure is sufficient to deform the mounting member () thereby deform the wafer to improve the flatness and parallelism of the surfaces of the successive wafer.

Method of polishing wafers

A process for forming a semiconductor wafer which is single side polished improves nanotopology and flatness of the polished wafer. The process reduces the effect of back side surface features, such as edge ring phenomena and back side laser marks, on nanotopology, thereby improving oxide layer uniformity for chemical/mechanical planarization (CMP) processing, and flatness on the polished front side of the wafer after polishing. The wafer is mounted on a polishing block by wax. The edge ring causes certain deformation and stress in the wafer upon mounting, which is held by the wax. After mounting, the wax is heated to allow the wafer to relax, removing the stress, without degrading the bond of the wafer to the polishing block. The wafer is polished and removed from the polishing blocks. The polished surface substantially retains its shape after being de-mounted from the block.

Process for reducing surface variations for polished wafer

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Sizzano, Italy

Giovanni Negri