Composite Substrate, Production Method Thereof, and Acoustic Wave Device

摘要

A composite substrate production method of the invention includes (a) a step of mirror polishing a substrate stack having a diameter of 4 inch or more, the substrate stack including a piezoelectric substrate and a support substrate bonded to each other, the mirror polishing being performed on the piezoelectric substrate side until the thickness of the piezoelectric substrate reaches 3 μm or less; (b) a step of creating data of the distribution of the thickness of the mirror-polished piezoelectric substrate; and (c) a step of performing machining with an ion beam machine based on the data of the thickness distribution so as to produce a composite substrate have some special technical features.

主权项

1. A composite substrate production method comprising:
(a) a step of mirror polishing a substrate stack having a diameter of 4 inch or more, the substrate stack including a piezoelectric substrate and a support substrate bonded to each other, the mirror polishing being performed on the piezoelectric substrate side until the thickness of the piezoelectric substrate reaches 3 μm or less; (b) a step of creating data of the distribution of the thickness of the mirror-polished piezoelectric substrate; and (c) a step of performing machining with an ion beam machine based on the data of the thickness distribution so as to produce a composite substrate wherein the piezoelectric substrate has a thickness of 3 μm or less, the difference between the largest thickness and the smallest thickness of the piezoelectric substrate is 60 nm or less over the entire plane surface, and the piezoelectric substrate has such crystallinity that the full width at half maximum of an X-ray diffraction rocking curve is 100 arcsec or less.