Finger biometric sensor assembly including direct bonding interface and related methods

1. A finger biometric sensor assembly comprising:

a finger biometric sensor integrated circuit (IC) die having a finger sensing area;

a cover layer aligned with the finger sensing area; and

a direct bonding interface between the finger biometric sensor IC die and the cover layer.

2. The finger biometric sensor assembly of claim 1 wherein the direct bonding interface comprises a hydrophilic direct bonding interface.

3. The finger biometric sensor assembly of claim 1 wherein the direct bonding interface comprises a hydrophobic direct bonding interface.

4. The finger biometric sensor assembly of claim 1 wherein the direct bonding interface comprises silicon oxynitride.

5. The finger biometric sensor assembly of claim 1 wherein the direct bonding interface comprises silicon oxide.

6. The finger biometric sensor assembly of claim 1 wherein the direct bonding interface has a dielectric constant in a range of 4-6.

7. The finger biometric sensor assembly of claim 1 wherein the direct bonding interface has a thickness less than 1 micron.

8. The finger biometric sensor assembly of claim 1 wherein the finger biometric sensor IC die comprises an uppermost passivation layer over the finger sensing area.

9. The finger biometric sensor assembly of claim 1 wherein the cover layer comprises sapphire.

10. The finger biometric sensor assembly of claim 1 wherein the cover layer comprises glass.

11. The finger biometric sensor assembly of claim 1 wherein the cover layer has a thickness in a range of 100-300 microns.

12. The finger biometric sensor assembly of claim 1 wherein the cover layer and the finger biometric sensor IC die have a combined thickness in a range of 150-200 microns.

13. The finger biometric sensor assembly of claim 1 further comprising a colored layer between the cover layer and the finger biometric sensor IC die.

14. An electronic device comprising:

a housing;

a user input device carried by the housing; and

a finger biometric sensor assembly carried by the user input device comprising

a finger biometric sensor integrated circuit (IC) die having a finger sensing area,

a cover layer aligned with the finger sensing area, and

a direct bonding interface between the finger biometric sensor IC die and the cover layer.

15. The electronic device of claim 14 wherein the direct bonding interface comprises a hydrophilic direct bonding interface.

16. The electronic device of claim 14 wherein the direct bonding interface comprises a hydrophobic direct bonding interface.

17. The electronic device of claim 14 wherein the direct bonding interface comprises silicon oxynitride.

18. The electronic device of claim 14 wherein the direct bonding interface comprises silicon oxide.

19. The electronic device of claim 14 wherein the user input device comprises a pushbutton switch input device.

20. A method of making a finger biometric sensor assembly comprising:

aligning a finger sensing areas of a finger biometric sensor integrated circuit (IC) die with a cover layer; and

forming a direct bonding interface between the finger biometric sensor IC die and the cover layer.

21. The method of claim 20 wherein forming the direct bonding interface comprises forming a hydrophilic direct bonding interface.

22. The method of claim 20 wherein forming the direct bonding interface comprises forming a hydrophobic direct bonding interface.

23. The method of claim 20 wherein forming the direct bonding interface comprises forming a direct bonding interface comprising silicon oxynitride.

24. The method of claim 20 wherein forming the direct bonding interface comprises forming a direct bonding interface comprising silicon oxide.

25. The method of claim 20 wherein forming the direct bonding interface comprises forming the direct bonding interface based upon a plasma treatment.

26. The method of claim 20 wherein the direct bonding interface is formed at a temperature of less than 200° C.