A polymer film including an adhesive layer, which can be peeled off with heat,
is bonded to the upper surface of a semiconductor layer. Then, a KrF excimer laser
light beam is applied to a surface of a substrate opposite to the semiconductor
layer. This causes local heating at the laser spot, so that the bonding of atoms
is cut off at the interface between the semiconductor layer and the substrate,
thereby forming a thermal decomposition layer between the substrate and the semiconductor
layer. Subsequently, the substrate is heated at a given temperature, so that the
adhesive layer foams to lose its adhesive power. As a result, the polymer film
is easily peeled off from the semiconductor layer.
