THE EFFECT OF SURFACE-ROUGHNESS ON THE RADIATIVE PROPERTIES OF PATTERNED SILICON-WAFERS

The radiative properties of patterned silicon wafers have a major impa ct on the two critical issues in rapid thermal processing (RTP), namel y wafer temperature uniformity and wafer temperature measurement. The surface topography variation of the die area caused by patterning and the roughness of the wafer backside can have a significant effect on t he radiative properties, but these effects are not well characterized. We report measurements of room temperature reflectance of a memory di e, logic die, and various multilayered wafer backsides. The surface ro ughness of the die areas and wafer backsides is characterized using at omic force microscopy (AFM). These data are subsequently used to asses s the effectiveness of thin film optics in providing approximations fo r the radiative properties of patterned wafers for RTP applications.