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

• US 8,629,539 B2
• Filed: 01/16/2012
• Issued: 01/14/2014
• Est. Priority Date: 01/16/2012
• Status: Active Grant

• Current Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Original Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Inventors: Milano, Shaun D., Doogue, Michael C., Taylor, William P.
• Primary Examiner(s): NGO, NGAN V
• Application Number:
  US13/350,970
• Publication Number:
  US 20130181304A1
• Time in Patent Office: 729 Days
• Field of Search: 257/676, 257/702, 438/123, 438/124
• US Class Current: 257/676
• CPC Class Codes: G01R 33/0029 Treating the measured signals, e.g. removing offset or noise
• 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 33/0076 Protection, e.g. with housings against stray fields
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: G01R 33/09 Magnetoresistive devices
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/4826 Connecting between the body and an opposite side of the item with respect to the body
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 23/3107 the device being completely enclosed
• CPC Class Codes: H01L 23/3142 Sealing arrangements between parts, e.g. adhesion promotors
• CPC Class Codes: H01L 23/49503 characterised by the die pad
• CPC Class Codes: H01L 23/49506 an insulative substrate being used as a diepad, e.g. ceramic, plastic H01L23/49531 takes precedence
• CPC Class Codes: H01L 23/49541 Geometry of the lead-frame
• CPC Class Codes: H01L 23/49575 : Assemblies of semiconductor devices on lead frames
• CPC Class Codes: H01L 24/17 : of a plurality of bump connectors
• 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 2924/00014 : 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 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/15747 : Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/30107 : Inductance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H10N 50/01 : Manufacture or treatment
• CPC Class Codes: H10N 50/10 : Magnetoresistive devices
• CPC Class Codes: H10N 50/80 : Constructional details
• CPC Class Codes: H10N 52/00 : Hall-effect devices integrated devices or assemblies of multiple devices H10N59/00
• CPC Class Codes: H10N 52/01 : Manufacture or treatment
• CPC Class Codes: H10N 52/101 : Semiconductor Hall-effect devices
• CPC Class Codes: H10N 52/80 : Constructional details

Abstract

Methods and apparatus to provide an integrated circuit package having a conductive leadframe, a non-conductive die paddle mechanically coupled to the leadframe, and a die disposed on the die paddle and electrically connected to the leadframe. With this arrangement, eddy currents are reduced near the magnetic field transducer to reduce interference with magnetic fields.

Claims

1. A device, comprising:

a conductive leadframe;

a non-conductive die paddle positioned in relation to the leadframe;

a die disposed on the die paddle;

at least one electrical connection from the die to the leadframe; and

a magnetic layer with the die to affect magnetic fields proximate the die.

2. The device according to claim 1, further including a magnetic transducer coupled to the die.

3. The device according to claim 2, wherein the magnetic transducer forms a part of the die.

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

5. The device according to claim 4, wherein the back bias magnet is screen printed.

6. The device according to claim 1, wherein the magnetic layer comprises a soft ferromagnetic material.

7. The device according to claim 1, wherein the magnetic layer comprises a hard ferromagnetic material.

8. The device according to claim 1, wherein the magnetic layer comprises a soft ferromagnetic material to provide a flux concentrator.

9. The device according to claim 1, wherein the die paddle comprises a plastic material.

10. The device according to claim 1, wherein the device comprises a Hall element.

11. The device according to claim 2, wherein the magnetic transducer comprises a magnetoresistive element.

12. The device according to claim 1, wherein the die does not overlap with any of the leadframe.

13. The device according to claim 2, wherein the magnetic transducer does not overlap with any of the leadframe.

14. A method, comprising:

employing a conductive leadframe;

forming a non-conductive die paddle in relation to the leadframe;

placing a die on the non-conductive die paddle to form an assembly;

forming at least one electrical connection between the die and the leadframe;

overmolding the assembly to form an integrated circuit package; and

forming a magnetic layer aligned with the die.

15. The method according to claim 14, further including coupling a magnetic transducer to the die.

16. The method according to claim 14, further including forming the non-conductive die paddle from a plastic material.

17. The method according to claim 15, further including molding the plastic die paddle.

18. The method according to claim 14, wherein the magnetic layer comprises a hard ferromagnetic material.

19. The method according to claim 14, wherein the magnetic layer comprises a soft ferromagnetic material.

20. The method according to claim 14, wherein the leadframe does not overlap with the die.

21. The method according to claim 15, wherein the magnetic transducer does not overlap with any of the leadframe.

22. The method according to claim 15, further including molding the magnetic layer within the die paddle.

23. The method according to claim 15, further including overmolding the die paddle, the die, and the magnetic layer.

24. The method according to claim 14, further including positioning a Hall element in the die.

25. The method according to claim 14, further including positioning a magnetoresistive element.