Devices using a metal layer with an array of vias to reduce degradation

• US 7,940,249 B2
• Filed: 10/31/2006
• Issued: 05/10/2011
• Est. Priority Date: 11/01/2005
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: AuthenTec Incorporated (Apple Inc.)
• Inventors: Perreault, George
• Primary Examiner(s): Shalwala; Bipin
• Assistant Examiner(s): Holton; Steven E
• Application Number:
  US11/591,242
• Publication Number:
  US 20070098228A1
• Time in Patent Office: 1,652 Days
• Field of Search: 345173-178, 178 1801- 1811, 200/600, 148/33.2, 324686-688, 382/124, 382/312, 382/316
• US Class Current: 345/173
• CPC Class Codes: G06V 40/1329 Protecting the fingerprint sensor against damage caused by the finger

Abstract

A device in accordance with the present invention has a top metal layer that shows increased resistance to degradation such as abrasion, erosion, or both. A device in accordance with the present invention includes a device layer and a top metal layer. The device layer includes contact sensing elements and has a plurality of depressions that extend into the device layer. The first metal layer overlies or is adjacent to the contact sensing elements and extends into the depressions. Preferably, a surface of the metal layer opposed to the device layer is contoured to the depressions. In some embodiments the top metal layer makes electrical connections to the contact sensor, but in other embodiments it does not. Preferably, the device forms a finger swipe sensor, and the contact sensing elements are coupled to finger swipe processing electronics.

Claims

1. A device comprising:

a device layer containing contact sensing elements and having a plurality of device layer depressions that extend into the device layer; and

a top metal layer overlying the device layer and extending into the depressions, the top metal layer also having a plurality of top metal layer depressions corresponding to the plurality of device layer depressions.

2. The device of claim 1, wherein a surface of the metal layer opposed to the device layer is contoured to the plurality of device layer depressions.

3. The device of claim 1, wherein the device layer further comprises a second metal layer electrically coupled to the first metal layer.

4. The device of claim 3, wherein the second metal layer is coupled to a ground.

5. The device of claim 1, wherein the plurality of device layer depressions comprise vies.

6. The device of claim 5, wherein the vias are arranged in a plurality of rows.

7. The device of claim 6, wherein vias in adjacent rows are offset from one another.

8. The device of claim 6, wherein vies in adjacent rows are aligned with one another.

9. The device of claim 1, wherein the plurality of device layer depressions comprise troughs.

10. The device of claim 9, wherein the troughs have elongated widths that extend in a direction perpendicular to a swipe direction of the device.

11. The device of claim 1, wherein the top most device layer that defines the device layer depressions is a passivation layer.

12. The device of claim 11, wherein the first metal layer is directly coupled to the passivation layer.

13. The device of claim 1, wherein the contact sensing elements comprise finger swipe sensing elements.

14. The device of claim 1, wherein the contact sensing elements comprise finger placement sensing elements.

15. The device of claim 1, wherein the contact sensing elements comprise analog pressure sensing elements.

16. The device of claim 1, wherein a surface of the first metal layer is exposed.

17. A contact sensor comprising:

a device layer containing contact sensing elements; and

a metal layer desposited above the device layer and patterned in acute planes that extend to and from the device layer.

18. The contact sensor of claim 17, wherein the contact sensing elements are capacitive sensing elements.

19. The contact sensor of claim 17, wherein the contact sensing elements are anyone of optical sensing elements, electromagnetic sensing elements, and thermal sensing elements.

20. The contact sensor of claim 17, wherein the device layer comprises integrated circuitry fabricated on a semiconductor substrate.

21. The contact sensor of claim 17, wherein the device layer comprises a plurality of vias and the metal layer extends into the plurality of vias.

22. The contact sensor of claim 21, wherein each of the plurality of vias has an aspect ratio of at least 10:

1.

23. The contact sensor of claim 17, wherein the metal layer does not overlie the contact sensing elements.

24. The contact sensor of claim 17, wherein the metal layer overlies the contact sensing elements.

25. A device comprising:

a contact sensing layer comprising multiple contact sensing elements and multiple patterned features that extend into the contact sensing layer; and

an exposed metal layer that extends into the multiple patterned features and having an exposed surface contoured to walls of the multiple patterned features, wherein the multiple patterned features divide the metal layer into multiple segments in a swipe direction of the device.

26. The device of claim 25, wherein the multiple patterned features comprise rows of vias.

27. The device of claim 26, wherein vias in adjacent rows are aligned with one another.

28. The device of claim 26, wherein vias in adjacent rows are offset from one another.

29. The device of claim 25, wherein the multiple patterned features comprise troughs.

30. The device of claim 25, further comprising a host module coupled to the device layer, wherein the host module is selected from the group consisting of a personal digital assistant, a cell phone, and a digital camera.

31. A method of fabricating a contact sensor comprising:

forming a contact sensing layer having a surface, one or more contact sensing elements, and patterned features that extend into the contact sensing layer; and

forming a metal layer over the contact sensing layer, wherein the metal layer extends into the patterned features and has an exposed surface contoured to the patterned features.

32. The method of claim 31, wherein forming the contact sensing layer comprises forming a passivation layer over the one or more contact sensing elements, wherein the passivation layer is patterned with the patterned features.

33. The method of claim 31, further comprising coupling the one or more contact sensing elements to finger swipe processing electronics.

34. The method of claim 31, further comprising coupling the one or more contact sensing elements to finger placement processing electronics.

35. The method of claim 31, further comprising coupling the one or more contact sensing elements to pressure sensitive processing electronics.

36. The method of claim 31, wherein the patterned features comprise a plurality of vias.

37. The method of claim 36, wherein the plurality of vias form an ordered array.

38. The method of claim 36, wherein the patterned features comprise a plurality of troughs.

39. The method of claim 38, wherein each of the plurality of troughs has an elongated width that extends in a direction perpendicular to a swipe direction of the contact sensor.