MULTI-SENSOR SYSTEM AND METHOD OF FORMING SAME

• US 20160320258A1
• Filed: 04/30/2015
• Published: 11/03/2016
• Est. Priority Date: 04/30/2015
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: ZHANG, Qing
• Granted Patent: US 10,082,438 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• 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: B81C 1/00015 for manufacturing microsystems
• 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: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up

Abstract

A method for forming a multi-sensor system includes forming an inertial sensor fixed electrode of an inertial sensor and a movable electrode of a pressure sensor on a first substrate having through silicon vias (TSVs). A second substrate is fusion bonded to a bonding layer on the first substrate. The second substrate and the bonding layer are patterned to form a transducer layer of the inertial sensor and a pressure sensor fixed electrode of the pressure sensor. The first substrate is etched to form a pressure sensor port aligned with the movable electrode. By simultaneously forming and monolithically integrating the inertial sensor and the pressure sensor into the multi-sensor system, the footprint of the multi-sensor system as well as the fabrication cost thereof is minimized.

Claims

1. A multi-sensor system comprising:

a first substrate;

a pressure sensor comprising;

a movable electrode aligned with a pressure sensor port, the pressure sensor port being within the first substrate; and

a pressure sensor fixed electrode comprising a first portion of a second substrate; and

an inertial sensor comprising;

an inertial sensor fixed electrode on the first substrate; and

a transducer layer comprising a second portion of the second substrate.

2. The multi-sensor system of claim 1 further comprising:

vias within the first substrate, the vias being configured to provide input/output signals to the pressure sensor and the inertial sensor.

3. The multi-sensor system of claim 1 further comprising:

a third substrate sealing the inertial sensor and providing a hermetic reference cavity for the pressure sensor.

4. The multi-sensor system of claim 3 wherein the third substrate comprises a transducer layer cavity aligned with the transducer layer.

5. The multi-sensor system of claim 3 further comprising connecting structures comprising posts, the third substrate being mounted to the posts.

6. The multi-sensor system of claim 5 further comprising:

a contact layer on the posts; and

contact pads on the third substrate, the contact layer being bonded to the contact pads to thereby mount the third substrate to the posts.

7. The multi-sensor system of claim 1 wherein the pressure sensor port extends at least partially through the first substrate.

8. The multi-sensor system of claim 7 further comprising an insulation layer on the first substrate, wherein the pressure sensor port extends entirely through the first substrate to the insulation layer, a pressure sensor diaphragm portion of the insulation layer exposed through the pressure sensor port forming a pressure sensor diaphragm of the pressure sensor.

9. The multi-sensor system of claim 7 wherein the pressure sensor port extends partially through the first substrate, a pressure sensing diaphragm portion of the first substrate being between the pressure sensor port and the movable electrode.

10. The multi-sensor system of claim 1 further comprising a plurality of pressure sensors comprising the pressure sensor, the pressure sensors configured to measure different pressures.

11. A method for forming a multi-sensor system, the method comprising:

forming a bonding layer on a first substrate;

bonding a second substrate to the bonding layer; and

patterning the second substrate and the bonding layer to form a transducer layer of an inertial sensor and a pressure sensor fixed electrode of a pressure sensor.

12. The method of claim 11 further comprising forming a sacrificial layer on the first substrate, the bonding layer being formed on the sacrificial layer, wherein the sacrificial layer is an etch stop for the patterning the second substrate and the bonding layer.

13. The method of claim 12 further comprising removing the sacrificial layer to release the transducer layer and the pressure sensor fixed electrode from the first substrate.

14. The method of claim 13 further comprising forming a passivation layer on the first substrate, the sacrificial layer being formed on the passivation layer, wherein the passivation layer is an etch stop for the removing the sacrificial layer.

15. The method of claim 11 further comprising:

forming vias within the first substrate, the vias being configured to provide input/output signals to the pressure sensor and the inertial sensor.

16. A method for forming a multi-sensor system, the method comprising:

forming an inertial sensor fixed electrode and a movable electrode on a first substrate;

forming a passivation layer on the inertial sensor fixed electrode and the movable electrode;

forming a sacrificial layer on the passivation layer,

forming a bonding layer on the sacrificial layer;

bonding a second substrate to the bonding layer;

patterning the second substrate and the bonding layer to form a transducer layer of an inertial sensor and a pressure sensor fixed electrode of a pressure sensor.

17. The method of claim 16 wherein the patterning the second substrate and the bonding layer further forms a connecting structure, the method further comprising mounting a third substrate to the connecting structure.

18. The method of claim 17 further comprising forming a transducer layer cavity within the third substrate, the transducer layer cavity being aligned with the transducer layer.

19. The method of claim 16 further comprising forming a pressure sensor port extending at least partially through the first substrate and aligned with the movable electrode.

20. The method of claim 20 wherein the pressure sensor port extends entirely through the first substrate, the passivation layer being exposed through the pressure sensor port.