Integrated MEMS pressure sensor and MEMS inertial sensor

Patent metadata

Field	Value
Publication number	US-9550668-B1
Application number	US-201514834498-A
Country	US
Kind code	B1
Filing date	Aug 25, 2015
Priority date	Aug 25, 2015
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

Integrated MEMS devices for pressure sensing and inertial sensing, methods for fabricating such integrated devices, and methods for fabricating vertically integrated MEMS pressure sensor/inertial sensor devices are provided. In an example, a method for fabricating an integrated device for pressure and inertial sensing includes forming a MEMS pressure sensor on a first side of a semiconductor substrate. The method further includes forming a MEMS inertial sensor on a second side of the semiconductor substrate. The second side of the semiconductor substrate is opposite the first side of the semiconductor substrate.

First claim

What is claimed is:

1. A method for fabricating an integrated MEMS device for pressure and inertial sensing, the method comprising:
forming a MEMS pressure sensor on a first side of a semiconductor substrate; and
forming a MEMS inertial sensor on a second side of the semiconductor substrate, wherein the second side of the semiconductor substrate is opposite the first side of the semiconductor substrate.

2. The method of claim 1 further comprising:
forming a membrane in the MEMS pressure sensor on the first side of the semiconductor substrate; and
capping the second side of the semiconductor substrate with a cap to enclose a cavity between the membrane and the cap.

3. The method of claim 1 further comprising:
forming a membrane in the MEMS pressure sensor on the first side of the semiconductor substrate; and
capping the second side of the semiconductor substrate with a cap to enclose a vacuum cavity between the membrane and the cap.

4. The method of claim 3 wherein the semiconductor substrate is a first semiconductor substrate and wherein the method further comprises bonding a second semiconductor substrate to the first side of the first semiconductor substrate.

5. The method of claim 4 further comprising etching through the second semiconductor substrate to form an open cavity in communication with the membrane.

6. The method of claim 1 wherein forming the MEMS inertial sensor on the second side of the semiconductor substrate comprises etching the semiconductor substrate to form a moveable comb structure and moveable proof mass from the semiconductor substrate.

7. The method of claim 1 wherein the semiconductor substrate is a first semiconductor substrate and wherein the method further comprise:
forming a membrane in the MEMS pressure sensor on the first side of the semiconductor substrate; and
bonding a first side of a third semiconductor substrate to the second side of the semiconductor substrate to enclose a cavity between the membrane and the third semiconductor substrate.

8. The method of claim 7 further comprising:
etching vias from the first side of the first semiconductor substrate to a second side of the third semiconductor substrate; and
forming conductive interconnects from the first side of the first semiconductor substrate to the second side of the third semiconductor substrate.

9. The method of claim 1 wherein forming the MEMS pressure sensor on the first side of the semiconductor substrate comprises:
forming a backplate member over a sacrificial layer in the first side of the semiconductor substrate; and
forming a membrane over the backplate member.

10. The method of claim 9 wherein forming the MEMS inertial sensor on the second side of the semiconductor substrate comprises:
etching through the semiconductor substrate to the sacrificial layer; and
removing the sacrificial layer to form a comb structure and proof mass from the semiconductor substrate.

11. A method for fabricating a vertically integrated MEMS pressure sensor/inertial sensor device, the method comprising:
providing a semiconductor substrate;
processing a first side of the semiconductor substrate to form a MEMS pressure sensor; and
processing a second side of the semiconductor substrate to form a MEMS inertial sensor.

12. The method of claim 11 wherein processing the first side of the semiconductor substrate and processing the second side of the semiconductor substrate comprises forming a cavity in the semiconductor substrate shared by the MEMS pressure sensor and the MEMS inertial sensor.

13. The method of claim 12 wherein the cavity is bound by a membrane formed on the first side of the semiconductor substrate and a cap formed on the second side of the semiconductor substrate.

14. The method of claim 11 wherein:
processing the first side of the semiconductor substrate to form the MEMS pressure sensor comprises forming a membrane on the first side of the semiconductor substrate; and
processing the second side of the semiconductor substrate to form the MEMS inertial sensor comprises forming cavity through the semiconductor substrate, wherein the cavity is bounded by the membrane and shared by the MEMS pressure sensor and the MEMS inertial sensor.

15. The method of claim 11 wherein the semiconductor substrate is a first semiconductor substrate and wherein the method further comprises:
bonding a second semiconductor substrate to the first side of the first semiconductor substrate; and
etching through the second semiconductor substrate to form an open cavity.

16. The method of claim 11 wherein processing the second side of the semiconductor substrate to form the MEMS inertial sensor comprises etching the semiconductor substrate to form a moveable comb structure and moveable proof mass from the semiconductor substrate.

17. The method of claim 11 wherein the semiconductor substrate is a first semiconductor substrate and wherein the method further comprises:
bonding a first side of a third semiconductor substrate to the second side of the first semiconductor substrate to enclose a cavity in the semiconductor substrate;
etching vias from the first side of the first semiconductor substrate to a second side of the third semiconductor substrate; and
forming conductive interconnects from the first side of the first semiconductor substrate to the second side of the third semiconductor substrate.

18. The method of claim 11 wherein processing the first side of the semiconductor substrate to form the MEMS pressure sensor comprises:
forming a backplate member over a sacrificial layer in the first side of the semiconductor substrate; and
forming a membrane over the backplate member.

19. The method of claim 18 wherein processing the second side of the semiconductor substrate to form the MEMS inertial sensor comprises:
etching through the semiconductor substrate to the sacrificial layer; and
removing the sacrificial layer to form a comb structure and proof mass from the semiconductor substrate.

20. An integrated MEMS device for pressure sensing and inertial sensing comprising:
a semiconductor substrate having a first side and a second side opposite the first side;
a MEMS pressure sensor located on the first side of the semiconductor substrate; and
a MEMS inertial sensor located on the second side of the semiconductor substrate.

Assignees

• Globalfoundries Sg Pte Ltd

Inventors

• Xia jia jie
• Ranganathan Nagarajan
• Kumar Rakesh
• Chatterjee Aveek Nath

Classifications

• B81B2201/0264

  Pressure sensors · CPC title

• B81B2203/0127

  Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function · CPC title

• B81B2207/094

  Feed-through, via · CPC title

• H01L29/84

  Electricity · mapped topic

• B81C1/00269

  Bonding of solid lids or wafers to the substrate · CPC title