Methods and Structures of Integrated MEMS-CMOS Devices

Patent metadata

Field	Value
Publication number	US-2016176708-A1
Application number	US-201514985388-A
Country	US
Kind code	A1
Filing date	Dec 30, 2015
Priority date	Mar 9, 2012
Publication date	Jun 23, 2016
Grant date	—

Abstract

A method for fabricating an integrated MEMS-CMOS device uses a micro-fabrication process that realizes moving mechanical structures (MEMS) on top of a conventional CMOS structure by bonding a mechanical structural wafer on top of the CMOS and etching the mechanical layer using plasma etching processes, such as Deep Reactive Ion Etching (DRIE). During etching of the mechanical layer, CMOS devices that are directly connected to the mechanical layer are exposed to plasma. This sometimes causes permanent damage to CMOS circuits and is termed Plasma Induced Damage (PID). Embodiments of the present invention presents methods and structures to prevent or reduce this PID and protect the underlying CMOS circuits by grounding and providing an alternate path for the CMOS circuits until the MEMS layer is completely etched.

First claim

1 - 11 . (canceled)

12 . A method for fabricating an integrated MEMS-CMOS device comprising:
providing a substrate having a surface region; forming a CMOS IC layer overlying the surface region, the CMOS IC layer having at least one CMOS electrode; forming a mechanical structural layer overlying the CMOS IC layer; forming at least one MEMS device overlying the CMOS IC layer from a first portion of the mechanical structural layer, the at least one MEMS devices having at least one MEMS electrode; and forming a protection structure from a second portion of the mechanical structural layer, the protection structure including one or more ground posts, a jumper, and an ESD diode, wherein the protection structure is coupled to the at least one MEMS electrode and the at least one CMOS electrode.

13 . The method of claim 12 wherein the ESD diode is coupled to the at least one CMOS electrode.

14 . The method of claim 12 wherein the jumper is coupled the at least one MEMS electrode and the at least one CMOS electrode.

15 . The method of claim 14 wherein the at least one MEMS electrode and the at least one CMOS electrode are electrically coupled via the jumper after the forming of the at least one MEMS device.

16 . The method of claim 12 further comprising forming an electrode ground ring structure overlying the at least one CMOS device, the electrode ground ring structure being coupled to ground and the at least one CMOS device.

17 . The method of claim 16 wherein the electrode ground ring structure is configured to direct plasma induced charge from a plasma etching process to ground.

18 . The method of claim 12 wherein the forming of the mechanical structural layer, the at least one MEMS device, and the protection structure comprises a plasma etching process.

19 . The method of claim 12 wherein the protection structure is configured to direct plasma induced charge from a plasma etching process to ground.

20 . The method of claim 12 wherein the one or more MEMS devices comprises an inertial sensor, an accelerometer, a gyrometer, a magnetic field sensor, a pressure sensor, a humidity sensor, a temperature sensor, a chemical sensor, or a biosensor.

21 . A method for fabricating an integrated MEMS-CMOS device comprising:
providing a substrate having a surface region; forming a CMOS IC layer overlying the surface region, the CMOS IC layer having at least one CMOS electrode; forming a mechanical structural layer overlying the CMOS IC layer, the mechanical structural layer including an electrically conductive mechanical structural layer that includes a first via coupled to the CMOS electrode, a second via coupled to a MEMS electrode, and one or more vias coupled to ground; and forming at least one MEMS device overlying the CMOS IC layer from a portion of the mechanical structural layer, the at least one MEMS devices coupled to the MEMS electrode; wherein the forming of the at least one MEMS device includes a plasma etching process that removes a portion of the electrically conductive mechanical structural layer to electrically separate the first via and the second via from the ground and maintain coupling between the first via and the second via to form a jumper for coupling the CMOS electrode and the MEMS electrode.

22 . The method of claim 21 comprising forming an ESD diode coupled to the at least one CMOS electrode.

23 . The device of claim 21 further comprising an electrode ground ring structure overlying the at least one CMOS device, the electrode ground ring structure being coupled to ground and the at least one CMOS device.

24 . The method of claim 21 wherein the at least one MEMS electrode and the at least one CMOS electrode are electrically coupled via the jumper after the forming of the at least one MEMS device.

25 . The method of claim 21 wherein the electrically conductive mechanical structural layer is configured to direct plasma induced charge from a plasma etching process to ground.

26 . The method of claim 21 wherein the one or more MEMS devices comprises an inertial sensor, an accelerometer, a gyrometer, a magnetic field sensor, a pressure sensor, a humidity sensor, a temperature sensor, a chemical sensor, or a biosensor.

27 . An integrated MEMS-CMOS device, comprising:
a CMOS IC layer overlying a surface region of a substrate, the CMOS IC layer having at least one CMOS electrode; at least one MEMS device a mechanical structural layer overlying the CMOS IC layer, the at least one MEMS devices coupled to a MEMS electrode; an electrically conductive mechanical structural layer overlying the CMOS IC layer, the electrically conductive mechanical structural layer including a first via coupled to a second via, the first via coupled to the CMOS electrode and the second via coupled to the MEMS electrode, the electrically conductive mechanical structural layer further includes one or more ground vias coupled to ground, the ground vias being electrically uncoupled to the first and second vias.

28 . The device of claim 27 , further comprising an ESD diode structure coupled to the at least one CMOS electrode.

29 . The device of claim 28 , wherein the ESD diode structure comprises a first diode coupling the at least one CMOS electrode to a power supply terminal and a first diode coupling the at least one CMOS electrode to a ground terminal.

30 . The device of claim 27 , further comprising an electrode ground ring structure overlying the at least one CMOS device, the electrode ground ring structure being coupled to ground and the at least one CMOS device

31 . The device of claim 27 , wherein the one or more MEMS devices comprises an inertial sensor, an accelerometer, a gyrometer, a magnetic field sensor, a pressure sensor, a humidity sensor, a temperature sensor, a chemical sensor, or a biosensor.

Assignees

• Mcube Inc

Inventors

• Sridharamurthy Sudheer S
• Lee Te-Hse Terrence
• Rastegar Ali J
• Stancu Mugurel
• Yang Xiao Charles

Classifications

• B81C2201/05

  Temporary protection of devices or parts of the devices during manufacturing · CPC title

• B81B2207/094

  Feed-through, via · CPC title

• B81B7/0064

  for protecting against electromagnetic or electrostatic interferences · CPC title

• B81C2201/0132

  Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling · CPC title

• B81C1/00238

  Joining a substrate with an electronic processing unit and a substrate with a micromechanical structure · CPC title