Methods for CMOS-MEMS integrated devices with multiple sealed cavities maintained at various pressures

Patent metadata

Field	Value
Publication number	US-9540230-B2
Application number	US-201213535180-A
Country	US
Kind code	B2
Filing date	Jun 27, 2012
Priority date	Jun 27, 2011
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

A Microelectromechanical systems (MEMS) structure comprises a MEMS wafer. A MEMS wafer includes a handle wafer with cavities bonded to a device wafer through a dielectric layer disposed between the handle and device wafers. The MEMS wafer also includes a moveable portion of the device wafer suspended over a cavity in the handle wafer. Four methods are described to create two or more enclosures having multiple gas pressure or compositions on a single substrate including, each enclosure containing a moveable portion. The methods include: A. Forming a secondary sealed enclosure, B. Creating multiple ambient enclosures during wafer bonding, C. Creating and breaching an internal gas reservoir, and D. Forming and subsequently sealing a controlled leak/breach into the enclosure.

First claim

What is claimed is:

1. A Microelectromechanical Systems (MEMS) device comprising:
a MEMS substrate with cavities bonded to a second substrate, forming a plurality of sealed enclosures, wherein each of the plurality of sealed enclosures is defined by the MEMS substrate, the second substrate, and a seal-ring material, wherein one of the plurality of sealed enclosures includes an inertial sensor;
wherein at least one of plurality of sealed enclosures further includes a non gettering out-gassing substance to desorb one or more gases to increase cavity pressure in the at least one of the plurality of sealed enclosures and at least one other of the plurality of sealed enclosures does not include the non gettering out-gassing substance;
wherein the at least one sealed enclosure with the non gettering out-gassing substance has a higher cavity pressure than the at least one other of the plurality of sealed enclosures without the non gettering out-gassing substance.

2. The MEMS structure of claim 1 , wherein the second substrate comprises a CMOS substrate.

3. The MEMS structure of claim 2 , wherein the CMOS substrate is electrically coupled to the MEMS substrate.

4. The MEMS structure of claim 2 , wherein the non gettering out-gassing substance is on one of the CMOS substrate or the MEMS substrate.

5. The MEMS structure of claim 1 , wherein the second substrate contains an integrated circuit.

6. The MEMS structure of claim 1 , wherein at an elevated temperature, a controlled amount of the one or more gases are desorbed from the non gettering out-gassing substance.

Assignees

• Daneman Michael
• Lim Martin
• Huang Kegang
• Tchertkov Igor
• Invensense Inc

Inventors

• Daneman Michael
• Lim Martin
• Huang Kegang
• Tchertkov Igor

Classifications

• B81C1/00293

  maintaining a controlled atmosphere with processes not provided for in B81C1/00285 · CPC title

• B81B7/02 Primary

  containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] (B81B7/04 takes precedence) · CPC title

• B81C1/0023

  Packaging together an electronic processing unit die and a micromechanical structure die (MEMS packages B81B7/0032; MEMS packaging processes B81C1/00261) · CPC title

• B81C2203/019

  characterised by the material or arrangement of seals between parts · CPC title

• B81C2203/0145

  Hermetically sealing an opening in the lid · CPC title