Patent ID: 8585847

Claim:
A method for manufacturing a composite substrate, comprising the steps of: (a) preparing a supporting substrate and a piezoelectric substrate having a beveled edge; (b) bonding a surface of the supporting substrate to the backside of the piezoelectric substrate with an organic adhesive layer interposed therebetween to form a laminated substrate; (c) grinding a peripheral surface of the laminated substrate such that a bevel of the piezoelectric substrate is removed and such that a peripheral surface of the piezoelectric substrate, a peripheral surface of the organic adhesive layer, and at least a portion of a peripheral surface of the supporting substrate on the side of the organic adhesive layer lie in the same vertical plane in the stacking direction of the piezoelectric/electrostrictive substrate, the organic adhesive layer and the supporting substrate so as to be flush with respect to each other; and (d) placing abrasive grains between the surface of the piezoelectric substrate and a lapping plate, and lapping the surface of the piezoelectric substrate with the lapping plate to reduce the thickness of the piezoelectric substrate and performing mirror polishing of the surface of the piezoelectric substrate, wherein the grinding of the peripheral surface of the laminated substrate in step (c) is performed so that at least part of the supporting substrate is removed while the initial outer diameter of the supporting substrate is maintained.