Surface characterization of aluminum substrates exposed to photoresist developers
Surface composition of aluminized substrates after exposure to sodium silicate buffered and non-buffered alkaline developers is described. Variable angle x-ray photoelectron scattering (XPS) reveals that sodium silicate buffered alkaline developers form a protective aluminosilicate film on the wafer surface which inhibits aluminum erosion. The elemental composition and possible mechanisms of film formation are presented. Aluminum-copper alloy sputtered wafers are more susceptible to etch by non-buffered alkaline developers than non-alloyed aluminum sputtered wafers.