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Safety and Health Topics > Semiconductors > Gallium Arsenide > Device Fabrication: Backlapping Device Fabrication: Backlapping Backlapping is done to remove deposited materials (GaAsP, Si3N4, etc.) from the backside of the wafer. The wafers are wax-mounted to a lapper plate and wet-lapped with a colloidal silica slurry. Then the wax is removed by wet-stripping the wafers in an organic stripper containing phenol, sulfonic acid, and chlorobenzenes in a locally exhausted wet chemical etch station. The wafers then receive a final cleaning. (See Silicon Device Manufacturing - Metallization - Backlapping and Backside Metallization) Potential Hazards Arsenic Nuisance Dust Machinery Chemicals Solvents Chemicals Potential Hazard Possible employee exposure to chemicals used for wet chemical etching. Common chemicals include phenol, sulfonic acid, and chlorobenzenes. Possible Solutions See the Possible Solutions: Chemicals page.

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