COMPOSITE WAFER AND MANUFACTURING METHOD THEREFOR

摘要

A composite wafer 10 includes a supporting substrate 12 and a semiconductor substrate 14 which are bonded to each other by direct bonding. The supporting substrate 12 is a translucent alumina substrate with an alumina purity of 99% or more. The linear transmittance of the supporting substrate 12 at the visible light range is 40% or less. Furthermore, the total light transmittance from the front at a wavelength of 200 to 250 nm of the supporting substrate 12 is 60% or more. The average crystal grain size of the supporting substrate 12 is 10 to 35 µm. The semiconductor substrate 14 is a single crystal silicon substrate. Such a composite wafer 10 has insulation performance and thermal conduction comparable to those of a SOS wafer, can be manufactured at low cost, and can be easily made to have a large diameter.