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

The invention is about a process for cleaning slurry from a carrier used for transporting wafers without interrupting the conventional CMP process. The process involves spraying the back-side of the carrier with a cleaning fluid at a specific time that does not interfere with the CMP process. The invention also includes a CMP machine with a spray nozzle that ejects fluid onto the back side of the carrier to wash off undesired slurry components. The spray nozzle is mounted within the indexing area of the CMP tool and is connected to a fluid source. The system includes flexible tubing and a plurality of spray nozzles mounted to the support mechanism for the wafer carriers. When the system actuates the fluid source for the front carrier wash, a flow of fluid is directed to the added tubing and nozzles to that fluid is sprayed onto the back side of the wafer carriers. Both the back side and front side of the carriers are washed concurrently.

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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