Temperature compensated resonator and method

• US 6,131,256 A
• Filed: 04/23/1997
• Issued: 10/17/2000
• Est. Priority Date: 06/29/1995
• Status: Expired due to Term

• Current Assignee: CDC Propriete Intellectuelle
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Welling, John Robert, Dydyk, Michael
• Primary Examiner(s): Young, Lee
• Assistant Examiner(s): TUGBANG, ANTHONY D
• Application Number:
  US08/839,117
• Time in Patent Office: 1,273 Days
• Field of Search: 310/329, 310/343, 310/346, 310/348, 29/25.35, 29/611, 29/594, 29/847
• US Class Current: 29/25.35
• CPC Class Codes: H03H 3/04 for obtaining desired frequency or temperature coefficient
• CPC Class Codes: H03H 9/02102 of temperature influence cutting angles H03H9/02015
• CPC Class Codes: H03H 9/173 Air-gaps
• CPC Class Codes: H03H 9/174 Membranes
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49083 Heater type

Abstract

A temperature compensated resonator (15) and method for making the temperature compensated resonator (15). The temperature compensated resonator (15) has a substrate (110) including a cavity (120, 160) and a resonator layer (150). A bonding medium (159, 160) couples the substrate (110) to the resonator layer (150). The resonator layer (150) is bonded atop the cavity (120, 160). A conductor (215) is included on the resonator layer (150). The conductor (215) heats the resonator layer (150) in response to a current passing through the conductor (215).

Claims

1. A method for making a temperature compensated resonator, said method comprising steps of:

providing a substrate including a cavity;

providing a resonator layer including a conductor disposed on said resonator layer, said resonator layer comprising a single-crystal piezoelectric material chosen from a group consisting of lithium niobate and lithium tantalate and having a first thickness in a range of one hundred micrometers to one millimeter; and

bonding said resonator layer to said substrate such that said resonator layer is disposed atop said substrate and said cavity, said step of bonding including a step of thinning said resonator layer to a second thickness less than said first thickness by a mechanical polishing technique, and wherein said step of bonding further includes a step of thinning said resonator layer to a third thickness less than said second thickness via a gas-phase etching process, and wherein said conductor is for heating said resonator layer during operation of said temperature compensated resonator in response to a current passing through said conductor.

2. A method for making a temperature compensated resonator as claimed in claim 1, wherein said step of providing a substrate including a cavity includes a step of providing a semiconductor substrate.

3. A method for making a temperature compensated resonator as claimed in claim 1, wherein said step of bonding further includes steps of:

depositing a metal film on said resonator layer; and

welding said resonator layer to said substrate by resistance heating of said metal film.

4. A method for making a temperature compensated resonator as claimed in claim 1, wherein said step of bonding further includes steps of:

depositing a metal film on said resonator layer; and

welding said resonator layer to said substrate by ultrasonic thermocompression welding said metal film.

5. A method for making a temperature compensated resonator as claimed in claim 1, wherein said step of bonding further includes a step of thinning said resonator layer to a third thickness less than twelve micrometers.