Characterizing stress in ultrathin silicon wafers

Abstract

The aim of this letter is to calculate the mechanical grinding induced bow and stress in ultrathin silicon wafers. The reverse leakage current of a p-n junction diode fabricated on a 4in. silicon wafer was measured for wafers thinned to various thicknesses. A correlation with the residual stress was obtained through band gap narrowing effect. The analytical results were compared with experimental bow measurements using a laser profiler. The bow in 50μm thick wafer was found to be less than 2mm using the current grinding process.