JP2008054277A5 - - Google Patents

Claims (11)

Has a linear expansion coefficient of ^{10 × 10 -6 / K~20 × 10} -6 / K, a substrate having a mirror-finished main surface, provided on the main surface, the linear expansion coefficient of the base material And a film made of a material having a linear expansion coefficient of −1 × 10 ⁻⁶ / K to 10 × 10 ⁻⁶ / K.   The piezoelectric substrate according to claim 1, wherein the film has a porosity of 5% to 40%.   The piezoelectric substrate according to claim 1, wherein the film is composed of a laminated body of particles.   The piezoelectric substrate according to claim 3, wherein the size of the particles is 5 μm to 300 μm.   Materials having a linear expansion coefficient smaller than that of the base material are Ti, W, Mo, Ta, Si and alloys thereof, aluminum oxide, silicon oxide, magnesium oxide, zirconium oxide, titanium oxide, silicon carbide, 5. The material according to claim 1, which is at least one selected from the group consisting of boron carbide, aluminum nitride, silicon nitride, a solid solution of these compounds, and a mixture of these metals and compounds. The piezoelectric substrate as described.   The piezoelectric film according to claim 1, wherein the film has a thickness of 0.05 mm to 2 mm.   The said base material is comprised by what was chosen from the group which consists of lithium tantalate, lithium niobate, a crystal | crystallization, lithium tetraborate, and a zinc oxide, The any one of Claim 1-6 characterized by the above-mentioned. 2. The piezoelectric substrate according to 1.   The piezoelectric substrate according to any one of claims 1 to 7, wherein an undercoat is provided between the base material and the film.   A piezoelectric substrate according to any one of claims 1 to 8, and an element provided on a main surface opposite to the roughened main surface of the piezoelectric substrate. Piezoelectric element. Has a linear expansion coefficient of ^{10 × 10 -6 / K~20 × 10} -6 / K, a step of preparing a substrate having a mirror-finished main surface, smaller than the linear expansion coefficient of the substrate, Forming a film made of a material having a linear expansion coefficient of −1 × 10 ⁻⁶ / K to 10 × 10 ⁻⁶ / K on the main surface. Production method.   11. The method for manufacturing a piezoelectric substrate according to claim 10, wherein the film is formed on the base material by a coating method using slurry, and the formed film is used as a support member for the base material.