Microscale sensor structure with backside contacts and packaging of the same

• US 10,461,239 B2
• Filed: 12/04/2017
• Issued: 10/29/2019
• Est. Priority Date: 12/06/2016
• Status: Active Grant

• Current Assignee: Interdisciplinary Consulting Corp.
• Original Assignee: Interdisciplinary Consulting Corp.
• Inventors: Mills, David Alan
• Primary Examiner(s): Choi, Calvin Y
• Application Number:
  US15/830,348
• Publication Number:
  US 20180159017A1
• Time in Patent Office: 694 Days
• CPC Class Codes: G01L 19/0069 from the sensor to its support
• CPC Class Codes: G01L 9/0005 using variations in capacitance G01L9/0072 takes precedence
• CPC Class Codes: G01L 9/08 by making use of piezoelectric devices , i.e. electric circuits therefor
• CPC Class Codes: G01L 9/12 by making use of variations in capacitance , i.e. electric circuits therefor
• CPC Class Codes: H01L 2224/05624 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45139 Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48106 the connector being orthogonal to a side surface of the semiconductor or solid-state body, e.g. parallel layout
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/4824 Connecting between the body and an opposite side of the item with respect to the body
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 2224/73215 Layer and wire connectors
• CPC Class Codes: H01L 2224/8385 using a polymer adhesive, e.g. an adhesive based on silicone, epoxy, polyimide, polyester
• CPC Class Codes: H01L 23/13 : characterised by the shape
• CPC Class Codes: H01L 24/05 : of an individual bonding area
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/49 : of a plurality of wire connectors
• CPC Class Codes: H01L 24/73 : Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 24/85 : using a wire connector wire bonding in general B23K20/004
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00011 : Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/0665 : Epoxy resin
• CPC Class Codes: H01L 2924/0781 : being an ohmic electrical conductor
• CPC Class Codes: H01L 2924/10156 : at the periphery
• CPC Class Codes: H01L 2924/35 : Mechanical effects
• CPC Class Codes: H10N 30/074 : by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
• CPC Class Codes: H10N 30/082 : by etching, e.g. lithography
• CPC Class Codes: H10N 30/302 : Sensors
• CPC Class Codes: H10N 30/853 : Ceramic compositions
• CPC Class Codes: H10N 30/875 : Further connection or lead arrangements, e.g. flexible wiring boards, terminal pins
• CPC Class Codes: H10N 30/883 : Further insulation means against electrical, physical or chemical damage, e.g. protective coatings

Abstract

A microscale sensor structure is provided that enables backside electrical connection to flush-mounted microscale sensors without through-wafer-vias (TWVs). A flush-mounted microscale sensor can be fabricated without TWVs by providing a sensor support substrate with openings for electrical connection access to the backside of a device layer. Backside electrical connection is made to the sensing element(s) of the device layer through the openings in the support substrate. Electrical isolation of the sensing element(s) from the support substrate is accomplished through use of an insulating support substrate and/or an insulating layer between the support substrate and the device layer.

Claims

1. A microscale sensor comprising:

a device layer having a front side and a back side, the front side of the device layer being positioned for exposure to a passing fluid;

a support substrate at the back side of the device layer, the support substrate having contact openings for accessing a conductive backside surface at the back side of the device layer, wherein electrical connection to the device layer is not formed with a through-wafer via; and

wherein the microscale sensor is configured to be flush mounted.

2. The microscale sensor of claim 1, further comprising:

an electrical circuit board on which the support substrate is attached.

3. The microscale sensor of claim 2, wherein the electric al circuit board comprises one or more openings exposing the contact openings of the support substrate from a back side of the electric al circuit board.

4. The microscale sensor of claim 3, wherein the electrical connection to the device layer attaches at one end to the back side of the device layer and attaches at the other end to the back side of the electrical circuit board, passing through one of the one or more openings of the electrical circuit board.

5. The microscale sensor of claim 2, wherein the electrical circuit board comprises a printed circuit board.

6. The microscale sensor of claim 2, wherein the electrical circuit board comprises an interposer.

7. The microscale sensor of claim 1, further comprising:

a sensor electrode on the front side of the device layer; and

one or more conductive vias within the device layer extending from the sensor electrode to the back side of the device layer for the electrical connection at the back side of the device layer.

8. The sensor of claim 1, wherein a capacitive shear stress sensor is formed in the device layer.

9. The sensor of claim 1, wherein the device layer comprises a piezoelectric material.

10. The microscale sensor of claim 1, wherein the support substrate is an insulating support substrate.

11. The microscale sensor of claim 10, wherein the insulating support substrate comprises glass.

12. The microscale sensor of claim 10, wherein the insulating support substrate comprises sapphire.

13. The microscale sensor of claim 1, further comprising an isolation layer between the support substrate and the device layer.

14. The microscale sensor of claim 13, wherein the isolation layer comprises silicon dioxide.

15. The microscale sensor of claim 13, wherein the isolation layer comprises silicon nitride.

16. The microscale sensor of claim 13, wherein the device layer and the support substrate are formed from a silicon-on-insulator (SOI) wafer, the isolation layer being formed of a buried oxide layer of the SOI wafer.

17. The microscale sensor of claim 1, wherein the electrical connection to the device layer comprises a wire bond.

18. The microscale sensor of claim 17, wherein the wire bond comprises gold, aluminum, silver, copper, or a combination thereof.

19. The microscale sensor of claim 1, wherein the electric al connection to the device layer comprises a conductive adhesive.