Mircomagnetic latching switch packaging

• US 20030011450A1
• Filed: 05/20/2002
• Published: 01/16/2003
• Est. Priority Date: 05/18/2001
• Status: Active Grant

• Current Assignee: Schneider Electric Industries SAS (Schneider Electric SE)
• Original Assignee: Magfusion, Inc. (Schneider Electric SE)
• Inventors: Shen, Jun, Stafford, John, Godavarti, Prasad S., Tam, Gordon
• Granted Patent: US 6,894,592 B2
• Time in Patent Office: Days
• US Class Current: 335/78
• CPC Class Codes: H01H 2050/007 Relays of the polarised type, e.g. the MEMS relay beam having a preferential magnetisation direction
• CPC Class Codes: H01H 50/005 using micromechanics

Abstract

Packages for a micromachined magnetic latching switch, and methods for assembling the packages are described. In one aspect, a substrate is defined by opposing first and second surfaces. A micromagnetic switch integrated circuit (IC) chip is mounted to the first surface. A contact pad on the chip is coupled to a trace on the first surface. A permanent magnet is positioned closely adjacent to the chip. A cap is attached to the first surface. An inner surface of the cap forms an enclosure to enclose the chip on the first surface. The chip can be alternatively mounted to the inner surface of the cap. The chip can be oriented in a standard or flip-chip fashion. In another aspect, a moveable micro-machined cantilever is supported by a surface of a substrate. A cap is attached to the surface. An inner surface of the cap forms an enclosure that encloses the cantilever on the surface of the substrate. A permanent magnet is positioned closely adjacent to the cantilever. An electromagnet is attached to the inner surface or an outer surface of the cap.

Claims

1. A package for a micromagnetic latching switch, comprising:

a substrate defined by opposing first and second surfaces, wherein said substrate includes a conductively filled via, wherein said via couples a trace on said first surface of said substrate to a solder ball pad on said second surface of said substrate;

a micromagnetic switch integrated circuit (IC) chip that is mounted to said first surface, wherein a contact pad on said chip is coupled to said trace;

a permanent magnet positioned closely adjacent to said chip; and

a cap attached to said first surface, wherein an inner surface of said cap forms an enclosure to enclose said chip on said first surface.

2. The package of claim 1, wherein said permanent magnet is attached to said inner surface of said cap.

3. The package of claim 1, further comprising:

a bond wire that couples said contact pad on said chip to said trace.

4. The package of claim 1, wherein said chip is flip chip mounted to said first surface.

5. The package of claim 4, wherein said permanent magnet is attached to said chip.

6. The package of claim 1, further comprising a solder ball attached to said solder ball pad.

7. A package for a micromagnetic latching switch, comprising:

a substrate defined by opposing first and second surfaces, wherein said substrate includes a conductively filled via, wherein said via couples a trace on said first surface of said substrate to a solder ball pad on said second surface of said substrate;

a cap attached to said first surface, wherein an inner surface of said cap forms an enclosure that encloses a portion of said first surface;

a micromagnetic switch integrated circuit (IC) chip that is mounted to said inner surface; and

a wire bond that couples a contact pad on said chip to said trace.

8. The package of claim 7, further comprising:

a permanent magnet positioned closely adjacent to said chip.

9. The package of claim 8, wherein said permanent magnet is mounted on said first surface.

10. A method for assembling a micromagnetic latching switch package, comprising the steps of:

(A) mounting a micromagnetic switch integrated circuit (IC) chip to a first surface of a substrate;

(B) coupling a contact pad on the chip to a trace on the first surface;

(C) positioning a permanent magnet closely adjacent to the chip; and

(D) attaching a cap to the first surface to enclose the chip on the first surface with an inner surface of the cap.

11. The method of claim 10, wherein step (C) includes the step of:

attaching the permanent magnet to the inner surface of the cap.

12. The method of claim 10, further comprising the step of:

(E) coupling the contact pad on the chip to the trace with a wire bond.

13. The method of claim 10, wherein step (A) includes the step of:

mounting the chip to the first surface in a flip chip orientation.

14. The method of claim 13, wherein step (C) includes the step of:

attaching the permanent magnet to the chip.

15. The method of claim 10, further comprising the step of:

(E) attaching a solder ball to a solder ball pad on a second surface of the substrate.

16. The method of claim 10, further comprising the step of:

(E) coupling a trace on the first surface of the substrate to a solder ball pad on a second surface of the substrate.

17. The method of claim 16, wherein step (E) comprises the steps of:

forming a via through the substrate between the first surface and the second surface; and

conductively filling the via.

19. The method of claim 18, further comprising the step of:

(D) coupling a trace on the first surface of the substrate to a contact pad on a second surface of the substrate.

20. The method of claim 19, wherein step (D) comprises the steps of:

forming a via through the substrate between the first surface and the second surface; and

conductively filling the via.

21. The method of claim 18, further comprising the step of:

(D) positioning a permanent magnet closely adjacent to the chip.

22. The method of claim 21, wherein step (D) comprises the step of:

mounting the permanent magnet on the first surface.

24. The package of claim 23, wherein said electromagnet includes:

a conductor; and

an insulator layer that insulates said conductor.

25. The package of claim 23, wherein said permanent magnet is attached to a second surface of said substrate.

26. The package of claim 23, wherein said electromagnet is attached to said inner surface.

27. The package of claim 23, wherein said electromagnet is coupled to said inner surface, further comprising:

a magnetic layer formed between said inner surface and said electromagnet.

28. The package of claim 23, wherein said electromagnet is attached to an outer surface of said cap.

29. The package of claim 28, further comprising:

a magnetic layer formed on said electromagnet.

18. A method for assembling a micromagnetic latching switch package, comprising the steps of:

(A) attaching a cap to a first surface of a substrate to enclose at least a portion of the first surface with an inner surface of the cap;

(B) mounting a micromagnetic switch integrated circuit (IC) chip to the inner surface; and

(C) coupling a contact pad on the chip to a trace on the first surface using a wire bond.

23. A package for a micromagnetic latching switch, comprising:

a substrate that has a surface;

a moveable micro-machined cantilever supported by said surface of said substrate

a cap attached to said surface of said substrate, wherein an inner surface of said cap forms an enclosure that encloses said cantilever on said surface of said substrate;

a permanent magnet positioned closely adjacent to said cantilever; and

an electromagnet attached to said cap.

30. A method for assembling a micromagnetic latching switch package, comprising:

(A) supporting a moveable micro-machined cantilever on a surface of a substrate;

(B) attaching a cap to the surface of the substrate to enclose the cantilever on the surface of the substrate with an inner surface of the cap;

(C) positioning a permanent magnet closely adjacent to the cantilever; and

(D) attaching an electromagnet to the cap.

31. The method of claim 30, further comprising the step of:

(E) forming the electromagnet, wherein step (E) includes the step of;

forming an insulating layer around a coil conductor.

32. The method of claim 30, wherein step (C) includes the step of:

attaching the permanent magnet to a second surface of the substrate.

33. The method of claim 30, wherein step (D) includes the step of:

attaching the electromagnet to the inner surface.

34. The method of claim 30, wherein step (D) includes the step of:

forming the electromagnet on the inner surface.

35. The method of claim 30, wherein step (D) includes the steps of:

forming a magnetic layer on the electromagnet; and

attaching the magnetic layer to the inner surface.

36. The method of claim 30, wherein step (D) includes the steps of:

forming a magnetic layer on the inner surface; and

forming the electromagnet on the magnetic layer.

37. The method of claim 30, wherein step (D) includes the step of:

attaching the electromagnet to an outer surface of the cap.

38. The method of claim 30, wherein step (D) includes the step of:

forming the electromagnet on an outer surface of the cap.

39. The method of claim 37, further comprising the step of:

forming a magnetic layer on the electromagnet.

40. The method of claim 38, further comprising the step of:

forming a magnetic layer on the electromagnet.