Ultraprecision grinding technologies in silicon semiconductor processing

Abstract

The production of silicon substrates for integrated circuits continues to set standards in levels of precision form and finish tolerances required of surface generation processes. Extreme tolerances are specified for a range of parameters such as total thickness variation, global and local planarity, and surface finish over substrate dimensions of up to 300mm in diameter (current-generation silicon wafer). These tolerances are related to the ‘design rule’ for each generation of microprocessor and memory unit. The economic and technological environment of an industry that demands such precision is reviewed. The general production process is then described with particular reference to surface grinding as an enabling technology. The context of developments in ultraprecision machine tool technology is delineated, requirements for assuring the indicated tolerances are set out and machine solutions representing the ‘state-of-the-art’ and ‘next-generation’ machine technologies reported.