Method and apparatus for cleaning slurry depositions from a water carrier

Abstract

Disclosed herein is a process for diminishing contamination of an integrated circuit wafer caused by residual slurry components disposed on a back side of a carrier for engaging an integrated circuit wafer. Also disclosed is a CMP machine configured to wash a back side of a carrier.

Description

[0001] Conventional chemical / mechanical polishing (CMP) is used to create smooth topographies of the various layers of a semiconductor integrated circuit wafer during semiconductor device manufacture. The CMP process involves holding and rotating, using a wafer carrier, semiconductor wafer against a rotating polishing pad. The wafer carrier is typically a plate-like structure having a diameter slightly larger than the semiconductor wafer. The carrier is attached to a positioning device through a gimbal on its back side surface that allows the carrier to be spun and to pivot on the gimbal. The polishing pad, which is conventionally an open-celled, polyurethane pad affixed to a polishing platen, is wetted by a chemical slurry, under controlled chemical, pressure, and temperature conditions. The chemical slurry contains selected chemicals which etch or oxidize selected surfaces of the wafer during CMP in preparation for their mechanical removal. The slurry also contains a polishing age...

AI Technical Summary

Benefits of technology

[0001] Conventional chemical / mechanical polishing (CMP) is used to create smooth topographies of the various layers of a semiconductor integrated circuit wafer during semiconductor device manufacture. The CMP process involves holding and rotating, using a wafer carrier, semiconductor wafer against a rotating polishing pad. The wafer carrier is typically a plate-like structure having a diameter slightly larger than the semiconductor wafer. The carrier is attached to a positioning device through a gimbal on its back side surface that allows the carrier to be spun and to pivot on the gimbal. The polishing pad, which is conventionally an open-celled, polyurethane pad affixed to a polishing platen, is wetted by a chemical slurry, under controlled chemical, pressure, and temperature conditions. The chemical slurry contains selected chemicals which etch or oxidize selected surfaces of the wafer during CMP in preparation for their mechanical removal. The slurry also contains a polishing agent, such as alumina or silica that is used as the abrasive material for the physical removal of the etched / oxidized material. The combination of chemical and mechanical removal of material during polishing results in superior planarization of the polished surface. In this process it is important to remove a sufficient amount of material to provide a smooth surface, without removing an excessive amount of underlying materials at each level of the manufacturing process to insure uniform and accurate formation of the semiconductor device at all subsequent levels. Accurate material removal is particularly important in today's sub-quarter micron technologies where it is critical to minimize thickness variation because the metal lines are thinner.

Problems solved by technology

Further, when this splashed slurry dries, the silica and / or other components in the slurry become a contamination issue.

Dried silica particles falling on the polishing pad is one of the causes of wafer scratches and failing particle counts when process checking a tool.

The scratching results in potential wafer yield losses.

The failing particle counts during process checking results in diminished tool availability since the tool must be taken out of production and cleaned.

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