Sensor module with mold encapsulation for applying a bias magnetic field

• US 8,080,993 B2
• Filed: 03/27/2008
• Issued: 12/20/2011
• Est. Priority Date: 03/27/2008
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Theuss, Horst, Wietschorke, Helmut
• Primary Examiner(s): LeDynh, Bot L
• Application Number:
  US12/056,776
• Publication Number:
  US 20090243595A1
• Time in Patent Office: 1,363 Days
• Field of Search: 324173-174, 324/207.2, 324/207.21, 324/207.25, 324/249, 324251-252, 735/143.1, 735/143.9, 123/612, 123/617, 257421-427, 327510-511, 438/15
• US Class Current: 324/251
• CPC Class Codes: B29C 45/14639 for obtaining an insulating effect, e.g. for electrical components
• CPC Class Codes: B29C 70/78 Moulding material on one side only of the preformed part
• CPC Class Codes: B29K 2995/0008 Magnetic or paramagnetic
• CPC Class Codes: G01D 5/147 influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other
• CPC Class Codes: G01P 1/026 for speed measuring devices, e.g. pulse generator
• CPC Class Codes: G01P 3/487 delivered by rotating magnets
• CPC Class Codes: G01R 33/0047 Housings or packaging of magnetic sensors packaging of semiconductor devices H01L23/00; Holders
• CPC Class Codes: H01L 2224/48091 Arched
• 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

Abstract

A method of manufacturing a sensor module includes providing a substrate comprising a magnetically sensitive sensor element. The sensor element and the substrate are encapsulated with at least one mold material that is configured to apply a bias magnetic field to the sensor element.

Claims

1. A method of manufacturing a sensor module, comprising:

providing a substrate comprising a magnetically sensitive sensor element;

encapsulating the sensor element and the substrate with at least one mold material that is configured to apply a bias magnetic field to the sensor element; and

applying a non-magnetic structure over the sensor element prior to the encapsulation, wherein the non-magnetic structure has one of a substantially conical shape and a substantially convex shape.

2. The method of claim 1,

wherein the at least one mold material encapsulates the sensor element, the non-magnetic structure, and the substrate.

3. The method of claim 2, wherein the non-magnetic structure comprises a polymer material.

4. The method of claim 2, wherein the non-magnetic structure comprises a photoresist material.

5. The method of claim 1, wherein the bias magnetic field is perpendicular to a plane of the sensor element.

6. The method of claim 1, wherein the mold material comprises a plurality of magnetic particles.

7. The method of claim 1, wherein the encapsulation is performed by an injection molding process or a compression molding process.

8. The method of claim 1, wherein the sensor element is a giant magneto resistance (GMR) element.

9. The method of claim 1, wherein the sensor element is a Hall element.

10. The method of claim 1, and further comprising:

applying at least one electrical interconnect to the substrate.

11. The method of claim 10, wherein the at least one electrical interconnect comprises at least one bond wire, and wherein the at least one mold material encapsulates the at least one bond wire.

12. The method of claim 1, wherein the substrate comprises a semiconductor die.

13. The method of claim 1, wherein the substrate comprises a plurality of magnetically sensitive sensor elements, and wherein the method further comprises:

applying a non-magnetic structure over each of the sensor elements prior to the encapsulation; and

wherein the at least one mold material encapsulates the plurality of sensor elements, the non-magnetic structures, and the substrate.

14. The method of claim 1, and further comprising:

applying the substrate to a carrier structure.

15. The method of claim 14, wherein the carrier structure is a lead frame.

16. The method of claim 14, wherein the at least one mold material encapsulates the sensor element, the substrate, and the carrier structure.

17. A sensor module, comprising:

a substrate comprising a magnetically sensitive element;

a non-magnetic structure positioned over the magnetically sensitive element, wherein the non-magnetic structure has one of a substantially conical shape and a substantially convex shape; and

at least one mold structure encapsulating the magnetically sensitive element and the substrate, the at least one mold structure configured to apply a bias magnetic field to the magnetically sensitive element.

18. The sensor module of claim 17,

wherein the at least one mold structure encapsulates the magnetically sensitive element, the non-magnetic structure, and the substrate.

19. A sensor module, comprising:

a semiconductor substrate comprising a magnetically sensitive element;

a polymer structure positioned over the magnetically sensitive element, wherein the polymer structure has one of a substantially conical shape and a substantially convex shape; and

a mold with magnetic particles encapsulating the polymer structure, the magnetically sensitive element, and the substrate, the mold configured to apply a bias magnetic field to the magnetically sensitive element.

20. A method of manufacturing a sensor module, comprising:

providing a substrate comprising a plurality of magnetically sensitive sensor elements;

encapsulating the sensor elements and the substrate with at least one mold material that is configured to apply a bias magnetic field to the sensor elements; and

applying a non-magnetic structure over each of the sensor elements prior to the encapsulation, wherein the at least one mold material encapsulates the plurality of sensor elements, the non-magnetic structures, and the substrate, wherein the non-magnetic structure has one of a substantially conical shape and a substantially convex shape.