Wafer bonding method for use in making a MEMS gyroscope

• US 10,012,670 B2
• Filed: 10/20/2014
• Issued: 07/03/2018
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: Insigh Tech LLC
• Original Assignee: Insigh Tech LLC
• Inventors: Zhang, Biao, Ju, Tao
• Primary Examiner(s): Kim, Paul D
• Application Number:
  US14/518,688
• Publication Number:
  US 20150034620A1
• Time in Patent Office: 1,352 Days
• CPC Class Codes: B81B 5/00 Devices comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements
• CPC Class Codes: B81C 1/00357 involving bonding one or several substrates on a non-temporary support, e.g. another substrate
• CPC Class Codes: B81C 2201/0197 Processes for making multi-layered devices not provided for in groups B81C2201/0176 - B81C2201/0192
• CPC Class Codes: B81C 2203/038 Bonding techniques not provided for in B81C2203/031 - B81C2203/037
• CPC Class Codes: B81C 3/001 Bonding of two components
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5776 Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
• CPC Class Codes: G01P 15/105 by magnetically sensitive devices
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01R 33/091 Constructional adaptation of the sensor to specific applications
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G01R 33/098 comprising tunnel junctions, e.g. tunnel magnetoresistance sensors

Abstract

A method of making a MEMS gyroscope is disclosed herein, wherein the MEMS gyroscope comprised a magnetic sensing mechanism on a magnetic sensor wafer and a magnetic source on a MEMS wafer that further comprises a proof-mass.

Claims

1. A method of making a microelectromechanical (MEMS) gyroscope, the method comprising:

providing a first substrate;

processing the first substrate, comprising;

forming a heater in a bonding area, comprising;

depositing a conductive material on a surface having the bonding area of the first substrate; and

patterning the conductive material so as to form the heater;

depositing an insulating layer on the patterned heater;

patterning the first substrate so as to form a cavity surrounded by a pillar; and

forming a magnetic source at a surface of a first MEMS wafer inside the cavity;

providing a second wafer that comprises a magnetic sensor;

bonding the first and second wafers at the bonding area so as to form a wafer assembly, further comprising;

driving current through the heater so as to raise temperature of a bonding material; and

bonding the first and second wafer by using the bonding material at the raised temperature; and

processing the first MEMS wafer of the wafer assembly so as to form a movable portion.

2. The method of claim 1, wherein the bonding material comprises a metal or a metal alloy.

3. The method of claim 2, wherein the magnetic sensor comprises a giant-magnetic-resistor.

4. The method of claim 2, wherein the magnetic sensors comprises a spin-valve structure.

5. The method of claim 2, wherein the magnetic sensors comprises a tunnel-magnetic-resistor.

6. The method of claim 2, wherein the magnetic sensor comprises a magnetic pickup coil that is an element of a fluxgate.