摘要 |
When an SOI substrate composed of a support wafer and an element formation wafer that are bonded together with an insulating film interposed therebetween is polished from a surface of the element formation wafer, a thickness of the element formation wafer is measured based on a relation between an intensity and a wavelength of a light that is irradiated to the SOI substrate from a side of the support wafer and is reflected by the SOI substrate. Thus, the measurement of the thickness of the element formation wafer can be performed simultaneouly with the polishing of the SOI substrate. |