MEMS sensor device with multi-stimulus sensing

• US 8,487,387 B2
• Filed: 06/18/2012
• Issued: 07/16/2013
• Est. Priority Date: 08/23/2010
• Status: Expired due to Fees

• Current Assignee: North Star Innovations Inc. (Wi-LAN Inc.)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Park, Woo Tae, Schlarmann, Mark E., Desai, Hemant D., Lin, Yizhen
• Primary Examiner(s): DANG, PHUC T
• Application Number:
  US13/526,279
• Publication Number:
  US 20120256282A1
• Time in Patent Office: 393 Days
• Field of Search: 257/415, 257/416, 257/E29.001, 438/113
• US Class Current: 257/415
• CPC Class Codes: B81B 2201/025 Inertial sensors not provided for in B81B2201/0235 - B81B2201/0242
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: G01L 19/0092 Pressure sensor associated with other sensors, e.g. for measuring acceleration or temperature G01L9/025, G01L9/045, G01L9/065, G01L9/085, G01L9/105, G01L9/125, G01L19/02, G01L19/04 take precedence; measuring two or more variable G01D21/02; temperature sensors with pressure compensation G01K1/26
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: G01P 2015/088 for providing wafer-level encapsulation
• CPC Class Codes: H01G 5/18 due to change in inclination, e.g. by flexing, by spiral wrapping
• CPC Class Codes: H01L 28/60 Electrodes

Abstract

A device (20, 90) includes sensors (28, 30) that sense different physical stimuli. A pressure sensor (28) includes a reference element (44) and a sense element (52), and an inertial sensor (30) includes a movable element (54). Fabrication (110) entails forming (112) a first substrate structure (22, 92) having a cavity (36, 100), forming a second substrate structure (24) to include the sensors (28, 30), and coupling (128) the substrate structures so that the first sensor (28) is aligned with the cavity (36, 100) and the second sensor (30) is laterally spaced apart from the first sensor (28). Forming the second structure (24) includes forming (118) the sense element (52) from a material layer (124) of the second structure (24) and following coupling (128) of the substrate structures, concurrently forming (132) the reference element (44) and the movable element (54) in a wafer substrate (122) of the second structure (24).

Claims

1. A microelectromechanical systems (MEMS) sensor device comprising;

a first substrate structure having a cavity formed therein;

a second substrate structure coupled with said first substrate structure, said second substrate structure having a first sensor and a second sensor formed therein, said second sensor being laterally spaced apart from said first sensor, and said first sensor being aligned with said cavity; and

a cap attached to said second substrate structure such that said first and second sensors are interposed between said cap and said first substrate structure, wherein said first sensor is exposed to an environment external to said MEMS sensor device via one of a group consisting of said cavity and said cap.

2. A MEMS sensor device as claimed in claim 1 wherein said second substrate structure comprises:

a wafer substrate;

an insulating layer formed on said wafer substrate; and

a material layer formed on said insulating layer, wherein a sense element of said first sensor is formed in said material layer, and said second substrate structure is coupled with said first substrate structure so that said sense element is interposed between said first substrate structure and said wafer substrate.

3. A MEMS sensor device as claimed in claim 2 wherein said sense element has a first thickness that is less than a second thickness of said wafer substrate.

4. A MEMS sensor device as claimed in claim 2 wherein a reference element of said first sensor and a movable element of said second sensor are concurrently formed in said wafer substrate.

5. A MEMS sensor device as claimed in claim 1 wherein said first sensor comprises:

a reference element formed in said second substrate structure and aligned with said cavity; and

a sense element interposed between said reference element and said cavity.

6. A MEMS sensor device as claimed in claim 5 wherein said first sensor is a pressure sensor, and sense element comprises a diaphragm spaced apart from said reference element to form a gap between said diaphragm and said reference element, said diaphragm being movable relative to said reference element in response to a pressure stimulus from said environment.

7. A MEMS sensor device as claimed in claim 1 wherein said second sensor is an inertial sensor comprising a movable element formed in said second substrate structure, said movable element being movable relative to a fixed element of said inertial sensor in response to a physical stimulus from said environment.

8. A MEMS sensor device as claimed in claim 1 wherein said cap comprises:

a first chamber in which said first sensor resides; and

a second chamber in which said second sensor resides, said second chamber being physically isolated from said first chamber.

9. A MEMS sensor device as claimed in claim 8 wherein:

said cavity has a depth that is less than a thickness of said first substrate structure; and

said cap includes a port extending through said cap into said first chamber to expose said first sensor to said environment external to said MEMS sensor device.

10. A MEMS sensor device as claimed in claim 8 wherein:

said first chamber of said cap is a hermetically sealed chamber; and

said cavity extends through a thickness of said first substrate structure such that said first sensor is exposed to said environment via said cavity.

11. A MEMS sensor device as claimed in claim 8 wherein said second chamber is a hermetically sealed chamber.

12. A microelectromechanical systems (MEMS) sensor device comprising;

a first substrate structure having a cavity formed therein;

a second substrate structure coupled with said first substrate structure, said second substrate structure having a first sensor and a second sensor formed therein, said second sensor being laterally spaced apart from said first sensor, said first sensor being aligned with said cavity, and said second substrate structure including;

a wafer substrate;

an insulating layer formed on said wafer substrate; and

a material layer formed on said insulating layer, wherein a sense element of said first sensor is formed in said material layer, and said second substrate structure is coupled with said first substrate structure so that said sense element is interposed between said first substrate structure and said wafer substrate; and

a cap attached to said second substrate structure such that said first and second sensors are interposed between said cap and said first substrate structure, said cap having a first chamber in which said first sensor resides, and said cap having a second chamber in which said second sensor resides, wherein said first sensor is exposed to an environment external to said MEMS sensor device via one of a group consisting of said cavity and said cap.

13. A MEMS sensor device as claimed in claim 12 wherein said sense element has a first thickness that is less than a second thickness of said wafer substrate.

14. A MEMS sensor device as claimed in claim 12 wherein a reference element of said first sensor and a movable element of said second sensor are concurrently formed in said wafer substrate.

15. A MEMS sensor device as claimed in claim 12 wherein a reference element of said first sensor and a movable element of said second sensor are formed in said wafer substrate after said second substrate structure is coupled with said first substrate structure.

16. A microelectromechanical systems (MEMS) sensor device comprising;

a first substrate structure having a cavity formed therein;

a second substrate structure coupled with said first substrate structure, said second substrate structure having a first sensor and a second sensor formed therein, said second sensor being laterally spaced apart from said first sensor, and said first sensor being aligned with said cavity, wherein;

said first sensor is a pressure sensor comprising a reference element formed in said second substrate structure and a diaphragm interposed between said reference element and said cavity, said diaphragm being spaced apart from said reference element to form a gap between said diaphragm and said reference element, and said diaphragm being movable relative to said reference element in response to a pressure stimulus from an environment external to said MEMS sensor device; and

said second sensor is an inertial sensor comprising a movable element formed in said second substrate structure, said movable element being movable relative to a fixed electrode element of said inertial sensor in response to a physical stimulus from said environment; and

a cap attached to said second substrate structure such that said pressure sensor and said inertial sensor are interposed between said cap and said first substrate structure, wherein said pressure sensor is exposed to said environment via one of a group consisting of said cavity and said cap.

17. A MEMS sensor device as claimed in claim 16 wherein said cap comprises:

a first chamber in which said pressure sensor resides; and

a second chamber in which said inertial sensor resides, said second chamber being physically isolated from said first chamber.

18. A MEMS sensor device as claimed in claim 17 wherein:

said cavity has a depth that is less than a thickness of said first substrate structure; and

said cap includes a port extending through said cap into said first chamber to expose said pressure sensor to said environment external to said MEMS sensor device.

19. A MEMS sensor device as claimed in claim 17 wherein:

said first chamber of said cap is a hermetically sealed chamber; and

said cavity extends through a thickness of said first substrate structure such that said pressure sensor is exposed to said environment via said cavity.

20. A MEMS sensor device as claimed in claim 17 wherein said second chamber is a hermetically sealed chamber.