Composite substrate, elastic wave device, and method for producing elastic wave device

Patent metadata

Field	Value
Publication number	US-9911639-B2
Application number	US-201514811953-A
Country	US
Kind code	B2
Filing date	Jul 29, 2015
Priority date	Feb 19, 2013
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A composite substrate 10 is formed by bonding together a piezoelectric substrate 12 and a support substrate 14 that has a lower thermal expansion coefficient than the piezoelectric substrate. The support substrate 14 is formed by directly bonding together a first substrate 14 a and a second substrate 14 b at a strength that allows separation with a blade, the first and second substrates being formed of the same material, and a surface of the first substrate 14 a is bonded to the piezoelectric substrate 12 , the surface being opposite to another surface of the first substrate 14 a bonded to the second substrate 14 b.

First claim

What is claimed is:

1. A composite substrate formed by bonding together a piezoelectric substrate and a support substrate that has a lower thermal expansion coefficient than the piezoelectric substrate,
wherein the support substrate is formed by directly bonding together a first substrate and a second substrate at a strength that allows separation with a blade, the first and second substrates being formed of the same material; and a surface of the first substrate is bonded to the piezoelectric substrate, the surface being opposite to another surface of the first substrate bonded to the second substrate.

2. The composite substrate according to claim 1 ,
wherein the first and second substrates are both silicon substrates.

3. The composite substrate according to claim 1 ,
wherein the strength that allows separation with a blade corresponds to a bonding energy per unit area of the first and second substrates in a range of 0.05 to 0.6 J/m 2 .

4. The composite substrate according to claim 1 ,
wherein the first and second substrates have a thickness of 100 to 600 μm.

5. The composite substrate according to claim 1 ,
wherein iron element and chromium element are contained between the first substrate and the second substrate.

Assignees

• Ngk Insulators Ltd

Inventors

• Hattori Ryosuke
• Hori Yuji
• Tai Tomoyoshi

Classifications

• H10P54/00

  Cutting or separating of wafers, substrates or parts of devices · CPC title

• H10P72/74 Primary

  using temporarily an auxiliary support · CPC title

• H03H3/08

  for the manufacture of resonators or networks using surface acoustic waves · CPC title

• B32B7/12

  using interposed adhesives or interposed materials with bonding properties · CPC title

• B32B9/04

  comprising such {particular} substance as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a glass layer B32B17/06; layered products with at least two ceramic layers composed mainly of ceramic B32B18/00)} · CPC title