Method for manufacturing a semiconductor substrate and device by bonding an epitaxial substrate to a first support substrate, forming a first and second protective thin film layer, and exposing and bonding a nitride semiconductor layer to a second support substrate

A method for manufacturing a semiconductor device, the method comprising:

• (a) preparing an epitaxial substrate formed by epitaxially growing a nitride semiconductor layer on a first main surface of a growth substrate being a nitride semiconductor substrate, and forming a nitride semiconductor element on the nitride semiconductor layer;
• (b) preparing a first support substrate, forming a resin adhesive layer between the first main surface of the growth substrate and a first main surface of the first support substrate so as to enclose the nitride semiconductor element, and bonding the epitaxial substrate to the first support substrate;
• (c) removing, after the step (b), a second main surface of the growth substrate to a prescribed thickness to thin the growth substrate, the second main surface of the growth substrate being on a side opposite to the first main surface of the growth substrate on which the nitride semiconductor element is formed;
• (d) forming, after the step (c), a first protective thin film layer from the second main surface of the thinned growth substrate to side surfaces of the resin adhesive layer;
• (e) forming, after the step (c), a second protective thin film layer from a second main surface of the first support substrate to the side surfaces of the resin adhesive layer, the second main surface of the first support substrate being on a side opposite to the first main surface of the first support substrate;
• (f) removing, after the steps (d) and (e), the thinned growth substrate and exposing the nitride semiconductor layer;
• (g) bonding, after the step (f), a second support substrate onto the nitride semiconductor layer;
• and
• (h) removing, after the step (g), the first support substrate and the resin adhesive layer.