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

• US 9,911,639 B2
• Filed: 07/29/2015
• Issued: 03/06/2018
• Est. Priority Date: 02/19/2013
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Hattori, Ryosuke, Hori, Yuji, Tai, Tomoyoshi
• Primary Examiner(s): Chen, Jack
• Application Number:
  US14/811,953
• Publication Number:
  US 20150328875A1
• Time in Patent Office: 951 Days
• Field of Search: None
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: B32B 2264/105 Metal
• CPC Class Codes: B32B 2307/20 having particular electrical or magnetic properties, e.g. piezoelectric
• CPC Class Codes: B32B 2307/206 Insulating
• CPC Class Codes: B32B 2307/538 Roughness
• CPC Class Codes: B32B 2309/02 Temperature
• CPC Class Codes: B32B 2309/105 Thickness
• CPC Class Codes: B32B 2457/00 Electrical equipment
• CPC Class Codes: B32B 2457/14 Semiconductor wafers
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/20 using fillers, pigments, thixotroping agents
• CPC Class Codes: B32B 27/283 comprising polysiloxanes
• CPC Class Codes: B32B 37/10 characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
• CPC Class Codes: B32B 38/10 Removing layers, or parts of layers, mechanically or chemically
• CPC Class Codes: B32B 7/025 Electric or magnetic properties
• CPC Class Codes: B32B 7/06 permitting easy separation
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B32B 9/005 comprising one layer of ceramic material, e.g. porcelain, ceramic tile layered products with at least two ceramic layers composed mainly of ceramic B32B18/00
• CPC Class Codes: B32B 9/04 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 Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 21/78 : with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H03H 2003/022 : the resonators or networks being of the cantilever type
• CPC Class Codes: H03H 2003/023 : the resonators or networks being of the membrane type
• CPC Class Codes: H03H 2003/027 : the resonators or networks being of the microelectro-mechanical [MEMS] type
• CPC Class Codes: H03H 3/02 : for the manufacture of piezoelectric or electrostrictive resonators or networks H03H3/08 takes precedence
• CPC Class Codes: H03H 3/08 : for the manufacture of resonators or networks using surface acoustic waves
• CPC Class Codes: H03H 3/10 : for obtaining desired frequency or temperature coefficient
• CPC Class Codes: H03H 9/02574 : of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate
• CPC Class Codes: H03H 9/1014 : the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the BAW device
• CPC Class Codes: H03H 9/1035 : the enclosure being defined by two sealing substrates sandwiching the piezoelectric layer of the BAW device
• CPC Class Codes: H03H 9/105 : the enclosure being defined by a cover cap mounted on an element forming part of the BAW device
• CPC Class Codes: H03H 9/25 : Constructional features of resonators using surface acoustic waves devices for manipulating acoustic surface waves in general G10K11/36
• CPC Class Codes: H10N 30/072 : by laminating or bonding of piezoelectric or electrostrictive bodies
• CPC Class Codes: H10N 30/8542 : Alkali metal based oxides, e.g. lithium, sodium or potassium niobates
• CPC Class Codes: Y10T 29/42 : Piezoelectric device making
• CPC Class Codes: Y10T 29/49005 : Acoustic transducer
• CPC Class Codes: Y10T 428/12597 : Noncrystalline silica or noncrystalline plural-oxide component [e.g., glass, etc.]

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 14a and a second substrate 14b 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 14a is bonded to the piezoelectric substrate 12, the surface being opposite to another surface of the first substrate 14a bonded to the second substrate 14b.

Claims

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/m².

4. The composite substrate according to claim 1,

wherein the first and second substrates have a thickness of 100 to 600 μ

m.

5. The composite substrate according to claim 1,

wherein iron element and chromium element are contained between the first substrate and the second substrate.