SENSOR AND A METHOD OF MANUFACTURE OF A SENSOR

• US 20130241543A1
• Filed: 03/14/2012
• Published: 09/19/2013
• Est. Priority Date: 03/14/2012
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Stenson, Bernard, O'Brien, Stephen, Canty, Matthew Thomas
• Granted Patent: US 9,817,087 B2
• Time in Patent Office: Days
• US Class Current: 324/252
• CPC Class Codes: G01R 33/0052 Manufacturing aspects; Manufacturing of single devices, i.e. of semiconductor magnetic sensor chips devices based on galvano-magnetic effect or the like H10N50/85
• CPC Class Codes: G01R 33/096 anisotropic magnetoresistance sensors
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

A method of manufacture of a sensor, the method comprising, in a first fabrication facility, forming one or more components of the sensor on a substrate; and in a second fabrication facility depositing a sensor layer, such as a magnetoresistive sensor, onto the substrate or over the one or more components. Otherwise contaminating effects of depositing magnetoresistive materials can thus be confined to the second fabrication facility, permitting more advanced fabrication equipment and techniques to be employed in the first fabrication facility.

Claims

1. A magnetoresistive sensor comprising:

a substrate;

a plurality of shorting bars; and

at least one magnetoresistive element formed over the substrate and the plurality of shorting bars, the at least one magnetoresistive element abutting and in electrical contact with the shorting bars.

2. A sensor as claimed in claim 1 wherein the shorting bars are angled with respect to a magnetically easy axis of the at least one magnetoresistive element.

3. A sensor as claimed in claim 1 wherein the plurality of shorting bars are inset into an insulating layer formed over the substrate.

4. A sensor as claimed in claim 1 further comprising an insulating layer formed above the magnetoresistive element.

5. A sensor as claimed in claim 1 wherein the shorting bars comprise tungsten.

6. A sensor as claimed in claim 1 wherein the magnetoresistive layer comprises Permalloy.

7. A sensor as claimed in claim 1 further comprising a plurality of conductive tracks in a connection layer configured to interconnect the at least one magnetoresistive element and at least one other circuit element, the connection layer being disposed between the substrate and the at least one magnetoresistive element, and further comprising an insulator disposed adjacent the shorting bars so as to prevent the shorting bars from directly making electrical contact with the conductive tracks.

8. A sensor as claimed in claim 7 further comprising vias for connecting the at least one magnetoresistive sensor to selected ones of the conductive tracks, said vias comprising tungsten and extending through the insulator.

9. A semiconductor integrated circuit comprising a sensor as claimed in claim 1.

10. A method of manufacture of a sensor, the method comprising:

in a first fabrication facility, forming one or more components of the sensor on a substrate; and

in a second fabrication facility depositing a sensor element onto the substrate or over the one or more components.

11. A method as claimed in claim 10 comprising:

in the first fabrication facility;

forming a plurality of shorting bars inset into the surface of a first dielectric layer or the substrate; and

in a second semiconductor fabrication facility;

depositing a sensor element over the plurality of shorting bars and the first dielectric layer or the substrate.

12. A method as claimed in claim 10 further comprising, in the first fabrication facility, forming first and second conductors to make electrical contact between the sensor element and electronic circuits formed on the substrate, or to external contacts.

13. A method as claimed in claim 10 wherein the sensor comprises a first dielectric layer and a second dielectric layer, and wherein the method further comprises:

depositing the second dielectric layer;

depositing a first conductive layer over the second dielectric layer;

etching the first conductive layer to form the first and second conductors;

depositing the first dielectric layer, and etching the first dielectric layer to expose selected portions of the first and second conductors for making contact with the sensor element.

14. A method as claimed in claim 10 further comprising:

depositing a flipping coil conducting layer;

removing at least part of the flipping coil conducting layer to form a flipping coil; and

depositing the second dielectric layer over the flipping coil.

15. A method as claimed in claim 10 wherein the substrate comprises silicon.

16. A method as claimed in claim 13 wherein at least one of the first dielectric layer and the second dielectric layer comprises silicon dioxide or silicon nitride.

18. A method as claimed in claim 10 wherein the plurality of shorting bars comprise tungsten.

19. A method as claimed in claim 11 wherein forming the shorting bars comprises forming a plurality of depressions in at least one of the substrate or the first dielectric layer, and depositing tungsten into the depressions.

20. A method as claimed in claim 19 further comprising performing at least one of chemical mechanical polishing (CMP) and etch back processes to remove tungsten from above a surface of the substrate or the first dielectric layer.

21. A method as claimed in claim 10 further comprising fabricating at least one integrated circuit on the semiconductor wafer in the first fabrication facility.

22. A method as claimed in claim 21 wherein one or more of the at least one integrated circuits is arranged to process signals from a sensing element formed by the sensor layer.

17. A method as claimed in 10 wherein the sensor element comprises Permalloy.

23. An integrated circuit, comprising:

a substrate;

a metallic layer patterned so as to form a plurality of conductive tracks for interconnecting circuit elements;

a thin film element; and

an insulating layer between the metallic layer and the thin film element, where connections between the thin film element and selected ones of the conductive tracks are made by metallic interconnectors extending though the insulating layer so as to connect the thin film element to other circuit components, the thin film element being positioned over the metallic interconnectors.

24. An integrated circuit as claimed in claim 23 wherein the thin film element has magnetoresistive properties.

25. An integrated circuit as claimed in claim 24 further comprising shorting bars formed in direct electrical and touching contact with the thin film element.

26. An integrated circuit as claimed in claim 25 wherein the shorting bars are surrounded by the insulating layer and the thin film element, such that the shorting bars do not physically contact with the plurality of conductors in the metallic layer.

27. An integrated circuit as clamed in claim 23 wherein the thin film element is a thin film resistor.

28. An integrated circuit as claimed in claim 23 wherein the thin film element is formed of at least two materials with different Seebeck coefficients, such that the at least two materials form a thermocouple.

29. An integrated circuit as claimed in claim 28 wherein at least one of the at least two materials comprises Bismuth Telluride.

30. An integrated circuit as claimed in claim 28 wherein the thermocouple is connected to at least one of a buffer, amplifier, or a signal processing circuit.

31. A method of manufacture of a sensor having a thin film sensor layer, the method comprising, in a first fabrication facility, forming one or more components of the sensor on a substrate, except the sensor layer.

32. A method of manufacture of a sensor, the method comprising receiving, at a second fabrication facility, a sensor comprised of one or more components or the sensor except a sensor layer on a substrate and depositing a sensor layer over the one or more components in the second fabrication facility.