Methods and apparatus for magnetic sensor having non-conductive die paddle

Patent metadata

Field	Value
Publication number	US-9620705-B2
Application number	US-201615049732-A
Country	US
Kind code	B2
Filing date	Feb 22, 2016
Priority date	Jan 16, 2012
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

Methods and apparatus to provide a magnetic field sensor device including a magnetic sensor element, a die having wafer bumps, wherein the magnetic sensor element is positioned in relation to the die, and conductive leadfingers having respective portions electrically connected to the wafer bumps. In embodiments, the device includes a region about the magnetic sensor element that does not contain electrically conductive material for preventing eddy current flow.

First claim

What is claimed is:

1. A magnetic field sensor device, comprising:
a magnetic sensor element;
a die having wafer bumps, wherein the magnetic sensor element is positioned in relation to the die;
a non-conductive die paddle over which the die is disposed;
conductive leadfingers having respective portions electrically connected to the wafer bumps; and
a region about the magnetic sensor element that does not contain electrically conductive leadfinger material for preventing eddy current flow.

2. The device according to claim 1 , wherein the non-conductive die paddle comprises a plastic material.

3. The device according to claim 1 , further including an underfill material proximate the wafer bumps.

4. The device according to claim 1 , further including a magnetic layer aligned with the die to affect magnetic fields proximate the die.

5. The device according to claim 4 , wherein the magnetic layer comprises a soft ferromagnetic material.

6. The device according to claim 4 , wherein the magnetic layer comprises a hard ferromagnetic material.

7. The device according to claim 1 , further including a back-bias magnet.

8. The device according to claim 1 , wherein the conductive leadfinger material is at least a given distance more than a height from the leadfingers to the magnetic sensing element.

9. The device according to claim 1 , wherein the conductive leadfinger material is at least two times a vertical height from the leadfingers to the magnetic sensing element.

10. The device according to claim 1 , wherein the magnetic sensor element is formed in the die.

11. The device according to claim 1 , wherein the magnetic sensor element includes a Hall element.

12. The device according to claim 1 , wherein the magnetic sensor element includes a magnetoresitive element.

13. The device according to claim 1 , wherein the leadfinger material extends from only one side of the magnetic field sensor device.

14. A method, comprising:
providing a magnetic sensor element;
providing a die having wafer bumps, wherein the magnetic sensor element is positioned in relation to the die;
providing conductive leadfingers having respective portions electrically connected to the wafer bumps; and
forming a region about the magnetic sensor element that does not contain electrically conductive material for preventing eddy current flow,
wherein the magnetic sensor element, the die, and the leadfingers form part of a magnetic field sensor IC package.

15. The method according to claim 14 , further providing a non-conductive die paddle on which the die is disposed.

16. The method according to claim 15 , wherein the non-conductive die paddle comprises a plastic material.

17. The method according to claim 14 , further including a magnetic layer aligned with the die to affect magnetic fields proximate the die.

18. The method according to claim 14 , further including a back-bias magnet as part of the IC package.

19. The method according to claim 14 , wherein the conductive leadfinger material is at least a given distance more than a height from the leadfingers to the magnetic sensing element.

20. The method according to claim 14 , wherein the conductive leadfinger material is at least two times a vertical height from the leadfingers to the magnetic sensing element.

21. The method according to claim 14 , wherein the magnetic sensor element is formed in the die.

22. The method according to claim 14 , wherein the magnetic sensor element includes a Hall element.

23. The method according to claim 14 , wherein the magnetic sensor element includes a magnetoresitive element.

24. The method according to claim 14 , wherein the leadfinger material extends from only one side of the magnetic field sensor device.

25. The method according to claim 14 , further including applying an underfill material proximate the wafer bumps.

26. A magnetic field sensor device, comprising:
a magnetic sensor element;
a die having wafer bumps, wherein the magnetic sensor element is positioned in relation to the die;
conductive leadfingers having respective portions electrically connected to the wafer bumps; and
a region about the magnetic sensor element that does not contain electrically conductive material for preventing eddy current flow,
wherein the leadfinger material extends from only one side of the magnetic field sensor device.

27. The device according to claim 26 , further including a non-conductive die paddle on which the die is disposed.

28. The device according to claim 26 , wherein the conductive leadfinger material is at least two times a vertical height from the leadfingers to the magnetic sensing element.

29. The device according to claim 26 , wherein the magnetic sensor element is formed in the die.

30. The device according to claim 26 , wherein the magnetic sensor element includes a Hall element.

31. The device according to claim 26 , wherein the magnetic sensor element includes a magnetoresitive element.

32. A method, comprising:
providing a magnetic sensor element;
providing a die having wafer bumps, wherein the magnetic sensor element is positioned in relation to the die; and
providing conductive leadfingers having respective portions electrically connected to the wafer bumps;
wherein a region about the magnetic sensor element does not contain electrically conductive material for preventing eddy current flow,
wherein the leadfinger material extends from only one side of the magnetic field sensor device, and
wherein the magnetic sensor element, the die, and the leadfingers form part of a magnetic field sensor IC package.

33. The method according to claim 32 , further including providing a non-conductive die paddle over which the die is disposed.

34. The method according to claim 32 , wherein the conductive leadfinger material is at least two times a vertical height from the leadfingers to the magnetic sensing element.

35. The method according to claim 32 , wherein the magnetic sensor element includes a Hall element.

36. The method according to claim 32 , wherein the magnetic sensor element includes a magnetoresitive element.

Assignees

• Allegro Microsystems Llc

Inventors

• Milano Shaun D
• Doogue Michael C
• Taylor William P

Classifications

• H10W72/5522

  comprising gold [Au] · CPC title

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W90/726

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W74/15

  on active surfaces of flip-chip devices, e.g. underfills · CPC title

• H10W74/00

  Encapsulations, e.g. protective coatings · CPC title