| abstract |
In a process of forming a single-crystalline semiconductor layer bonded to a glass substrate by low-temperature heat treatment, before a bonding and separation step in which the single-crystalline semiconductor layer is bonded to the glass substrate, the glass substrate is heated at a temperature higher than a heat temperature in the bonding and separation step. In a bonding step between the single-crystalline semiconductor layer and the glass substrate, the single-crystalline semiconductor layer is heated at a temperature close to a strain point of the glass substrate, specifically at a temperature in a range from minus 50° C. to plus 50° C. of a strain point. Accordingly, the glass substrate is subjected to heat treatment in advance at a temperature higher than the temperature close to the strain point, specifically, at a temperature higher than the temperature in a range from minus 50° C. to plus 50° C. of the strain point. |