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

Patent metadata

Field	Value
Publication number	US-10629470-B2
Application number	US-201715802967-A
Country	US
Kind code	B2
Filing date	Nov 3, 2017
Priority date	Feb 19, 2013
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

A method for producing an elastic wave device includes steps of (a) preparing a first substrate and a second substrate, (b) irradiating a bonding surface of the first substrate and a bonding surface of the second substrate with one of plasma, neutral atom beams, and ion beams of an inert gas, (c) bonding the bonding surface of the first substrate and the bonding surface of the second substrate in a vacuum at room temperature so as to set a strength that allows the first and second substrates to be separated by insertion of a blade; (d) forming a composite substrate by bonding a piezoelectric substrate to another surface of the first substrate; (e) forming electrode on a surface of the piezoelectric substrate of the composite substrate; and then (f) removing the second substrate from the first substrate by separation with the blade.

First claim

What is claimed is:

1. A method for producing an elastic wave device comprising the steps of:
(a) preparing a first substrate and a second substrate;
(b) irradiating a bonding surface of the first substrate and a bonding surface of the second substrate with one of plasma, neutral atom beams, and ion beams of an inert gas;
(c) bonding the bonding surface of the first substrate and the bonding surface of the second substrate in a vacuum at room temperature so as to set a strength that allows the first substrate and the second substrate to be separated by insertion of a blade having a thickness of 100 μm;
(d) forming a composite substrate by bonding a piezoelectric substrate to another surface of the first substrate that is opposite to the bonding surface of the first substrate;
(e) forming electrodes on a surface of the piezoelectric substrate of the composite substrate; and
(f) after forming the electrodes (c) step, removing the second substrate from the first substrate by separation with the blade,
wherein the first substrate and the second substrate are formed of a same material and each of the first substrate and the second substrate has a lower thermal expansion coefficient than that of the piezoelectric substrate.

2. The method for producing an elastic wave device according to claim 1 , further comprising the step of:
(g) after removing the second substrate from the first substrate, dicing the composite substrate to obtain the elastic wave device.

3. The method for producing an elastic wave device according to claim 1 ,
wherein the first and second substrates are both silicon substrates.

4. The method for producing an elastic wave device according to claim 1 ,
wherein the strength that allows separation with the blade corresponding to a bonding energy per unit area of the first and second substrates is in a range of 0.05 to 0.06 J/m 2 .

5. The method for producing an elastic wave device according to claim 1 ,
wherein an iron element and a chromium element are contained between the bonding surface of the first substrate and the bonding surface of 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

• B32B2264/105

  Metal · CPC title

• B32B2457/00

  Electrical equipment · CPC title

• B32B2457/14

  Semiconductor wafers · CPC title