Quartz-based nanoresonators and method of fabricating same

• US 7,459,099 B2
• Filed: 01/25/2005
• Issued: 12/02/2008
• Est. Priority Date: 04/30/2002
• Status: Expired due to Term

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Kubena, Randall L., Chang, David T., Kim, Jinsoo
• Primary Examiner(s): OLSEN, ALLAN W
• Application Number:
  US11/043,378
• Publication Number:
  US 20050158905A1
• Time in Patent Office: 1,407 Days
• Field of Search: None
• US Class Current: 216/57
• CPC Class Codes: H03H 2003/0414 Resonance frequency
• CPC Class Codes: H03H 2009/241 Bulk-mode MEMS resonators
• CPC Class Codes: H03H 3/04 for obtaining desired frequency or temperature coefficient
• CPC Class Codes: H03H 9/19 consisting of quartz
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/4908 Acoustic transducer
• CPC Class Codes: Y10T 29/49128 Assembling formed circuit to base
• CPC Class Codes: Y10T 29/49165 by forming conductive walled aperture in base

Abstract

A method for fabricating a quartz nanoresonator which can be integrated on a substrate, along with other electronics is disclosed. In this method a quartz substrate is bonded to a base substrate. The quartz substrate is metallized so that a bias voltage is applied to the resonator, thereby causing the quartz substrate to resonate at resonant frequency greater than 100 MHz. The quartz substrate can then be used to drive other electrical elements with a frequency equal to its resonant frequency. The quartz substrate also contains tuning pads to adjust the resonant frequency of the resonator. Additionally, a method for accurately thinning a quartz substrate of the resonator is provided. The method allows the thickness of the quartz substrate to be monitored while the quartz substrate is simultaneously thinned.

Claims

1. A method useful for thinning a quartz substrate comprising:

providing a quartz substrate;

removing a first portion of the quartz substrate using a first lap and polishing process;

removing a second portion of the quartz substrate using a second lap and polishing process, wherein the second lap and polishing process uses softer chemical than the first lap and polishing process; and

removing a third portion of the quartz substrate using reactive ion etching after removing the second portion, while simultaneously monitoring the thickness of the quartz substrate while removing the third portion, wherein the quartz substrate is stationary while removing the third portion and monitoring the thickness.

2. The method of claim 1, wherein the first lap and polish process uses aluminum oxide.

3. The method of claim 1, wherein the second lap and polish process uses silica or cerium oxide.

4. The method of claim 1, wherein reactive ion etching uses a gas having a fluorine chemistry.

5. The method of claim 1, wherein measuring is performed using spectroscopic ellipsometry.

6. The method of claim 1, wherein measuring is performed using reflectometry.

7. The method of claim 1, wherein the quartz substrate is thinned to a thickness less than 10 micrometers.

8. The method of claim 1, wherein the first portion is larger than the second portion.

9. The method of claim 1, further comprising performing an additional lap and polish process using cerium oxide after removing a third portion.

10. The method of claim 9, further comprising wet etching the quartz substrate using ammonium bifluoride after performing the additional lap and polish process.

11. The method of claim 1, wherein the quartz substrate is a wafer.

12. The method of claim 11, wherein the wafer is 3 inches or larger.