Sensor device and related fabrication methods

• US 9,046,546 B2
• Filed: 04/27/2012
• Issued: 06/02/2015
• Est. Priority Date: 04/27/2012
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Lin, Yizhen
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): COTEY, PHILIP L
• Application Number:
  US13/458,537
• Publication Number:
  US 20130283912A1
• Time in Patent Office: 1,131 Days
• Field of Search: 735/141.6, 737/17, 737/00, 737/16, 737/24, 737/08, 737/15
• US Class Current: 1/1
• CPC Class Codes: G01L 13/025 using diaphragms
• CPC Class Codes: G01L 15/00 Devices or apparatus for measuring two or more fluid pressure values simultaneously
• 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 19/02 Arrangements for preventing, or for compensating for, effects of inclination or acceleration of the measuring device; Zero-setting means for aneroid barometers G01L7/14
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0047 Diaphragm with non uniform thickness, e.g. with grooves, bosses or continuously varying thickness
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: G01L 9/125 with temperature compensating means non electric temperature compensating means G01L19/04
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

Apparatus and related fabrication methods are provided for a sensor device. An exemplary sensor device includes a first structure including a first sensing arrangement and a second sensing arrangement formed therein and a second structure affixed to the first structure. The second structure includes a cavity aligned with the first sensing arrangement to provide a first reference pressure on a first side of the first sensing arrangement and an opening aligned with the second sensing arrangement to expose the first side of the second sensing arrangement to an ambient pressure.

Claims

1. A sensor device comprising:

a first structure including a first sensing arrangement and a second sensing arrangement formed therein;

a second structure affixed to the first structure, wherein the second structure includes;

a cavity aligned with the first sensing arrangement to provide a first reference pressure on a first side of the first sensing arrangement; and

an opening aligned with the second sensing arrangement to expose the first side of the second sensing arrangement to an ambient pressure; and

a third structure coupled to a second side of the first structure to provide a sealed chamber adjacent to the second side of the first sensing arrangement and the second side of the second sensing arrangement, the sealed chamber providing a second reference pressure on the second side of the first sensing arrangement and the second reference pressure on the second side of the second sensing arrangement, wherein the first reference pressure and the second reference pressure are different.

2. The sensor device of claim 1, wherein:

the first sensing arrangement includes a first diaphragm region to deflect in response to a difference between the first reference pressure and the second reference pressure; and

the second sensing arrangement includes a second diaphragm region to deflect in response to a difference between the ambient pressure and the second reference pressure.

3. The sensor device of claim 1, further comprising a third sensing arrangement formed in the first structure, wherein:

the third structure provides the sealed chamber adjacent to the second side of the third sensing arrangement.

4. The sensor device of claim 1, further comprising a molding compound encapsulating the third structure.

5. The sensor device of claim 1, further comprising a third sensing arrangement formed in the first structure.

6. The sensor device of claim 5, wherein the third sensing arrangement comprises an inertial sensing arrangement.

7. The sensor device of claim 1, wherein:

the first sensing arrangement comprises a first pressure sensing arrangement; and

the second sensing arrangement comprises a second pressure sensing arrangement.

8. The sensor device of claim 7, wherein:

the first reference pressure is at vacuum; and

the second reference pressure on the second side of the first sensing arrangement and the second side of the second sensing arrangement is at partial vacuum.

9. The sensor device of claim 1, wherein:

the first sensing arrangement comprises a first pressure sensing arrangement; and

the second sensing arrangement comprises a second pressure sensing arrangement.

10. The sensor device of claim 9, the first pressure sensing arrangement including a first diaphragm region and the second pressure sensing arrangement including a second diaphragm region, deflection of the first diaphragm region being influenced by the first reference pressure, wherein deflection of the second diaphragm region is influenced by the ambient pressure and independent of the first reference pressure.

11. The sensor device of claim 10, further comprising control circuitry to determine a pressure metric indicative of the ambient pressure based on a relationship between a first electrical signal from the first sensing arrangement and a second electrical signal from the second sensing arrangement, wherein the first electrical signal is influenced by the deflection of the first diaphragm region and the second electrical signal is influenced by the deflection of the second diaphragm region.

12. The sensor device of claim 1, wherein:

the first sensing arrangement includes a first diaphragm region;

the second sensing arrangement includes a second diaphragm region exposed to an ambient pressure;

the cavity comprises a second sealed chamber adjacent to a first side of the first sensing arrangement, the second sealed chamber having the first reference pressure, wherein first diaphragm region deflects in response to a difference between the first reference pressure and the second reference pressure and the second diaphragm region deflects in response to a difference between the ambient pressure and the second reference pressure.

13. The sensor device of claim 12, further comprising an integrated circuit die having control circuitry formed thereon, the control circuitry being coupled to the sensor device to determine a pressure metric indicative of the ambient pressure based on a relationship between a first electrical signal from the first sensing arrangement and a second electrical signal from the second sensing arrangement, wherein the first electrical signal is influenced by the deflection of the first diaphragm region and the second electrical signal is influenced by the deflection of the second diaphragm region.

14. The sensor device of claim 13, further comprising a package substrate structure having the sensor device and the integrated circuit die affixed thereto, wherein the package substrate structure includes a second opening aligned with the second sensing arrangement to expose the second diaphragm region to the ambient pressure.

15. The sensor device of claim 12, further comprising:

an inertial sensing arrangement; and

a substrate of semiconductor material having the first sensing arrangement, the second sensing arrangement, and the inertial sensing arrangement formed therein, wherein the sealed chamber encompasses a side of the inertial sensing arrangement.

16. A method of fabricating the sensor device of claim 1, the method comprising:

forming the second structure having the cavity;

affixing the second structure to the first side of the first structure at the first reference pressure, the cavity providing a second sealed chamber at the first reference pressure adjacent to the first side of the first sensing arrangement of the first structure in response to affixing the first structure to the second structure;

forming the opening in the second structure, the opening being aligned with the second sensing arrangement of the first structure to expose the first side of the second sensing arrangement to the ambient pressure; and

affixing the third structure to the second side of the first structure at the second reference pressure, the third structure being configured to provide the sealed chamber at the second reference pressure adjacent to the second side of the first sensing arrangement and the second sensing arrangement in response to affixing the third structure to the first structure.

17. The method of claim 16, further comprising:

forming a first diaphragm region for the first sensing arrangement on the first structure, the first side of the first diaphragm region being adjacent to the second sealed chamber when the second structure is affixed to the first structure;

forming a second diaphragm region for the second sensing arrangement on the first structure, the opening in the second structure being aligned with the second diaphragm region to expose the first side of the second diaphragm region to the ambient pressure; and

forming openings in the first structure to expose the second side of the first diaphragm region and the second side of the second diaphragm region to the second reference pressure.

18. The method of claim 17, further comprising forming a third sensing arrangement in the first structure, wherein the third sensing arrangement is at the second reference pressure when the third structure is affixed to the first structure.