Shielded PC board for magnetically sensitive integrated circuits

• US 6,625,040 B1
• Filed: 08/31/2000
• Issued: 09/23/2003
• Est. Priority Date: 08/31/2000
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Tuttle, Mark
• Primary Examiner(s): Gandhi, Jayprakash N.
• Application Number:
  US09/653,558
• Time in Patent Office: 1,118 Days
• Field of Search: 361/748, 361/762, 361/777, 361/800, 361/816, 361/818, 361/803, 174/35.R, 174/255, 174/256, 257/659
• US Class Current: 361/816
• CPC Class Codes: G11C 11/14 using thin-film elements
• CPC Class Codes: G11C 5/04 Supports for storage elements , e.g. memory modules; Mounting or fixing of storage elements on such supports
• CPC Class Codes: H05K 1/0233 Filters, inductors or a magnetic substance

Abstract

A method and packaging device which provide a magnetically permeable shield for integrated circuits containing magnetic field sensitive circuit elements are disclosed. One or more magnetic shields are provided on, or embedded within, a printed circuit board and additional shielding elements are provided over the printed circuit board.

Claims

1. A printed circuit board for supporting integrated circuits sensitive to external magnetic fields, said printed circuit board comprising:

a support body having at least one surface containing locations for supporting at least one magnetic memory structure of said integrated circuits; and

a magnetically shielding structure coupled to said support body for shielding at least one surface of said integrated circuits supported on said support body, wherein said magnetically shielding structure comprises one or more separate layers of electrically non-conductive magnetic material, each of said layers coupled to a surface of said support body, said one or more separate layers forming a discontinuous shield of integrated circuits.

2. The printed circuit board of claim 1, wherein said magnetically shielding structure shields top and bottom surfaces of said integrated circuits supported on said support body.

3. The printed circuit board of claim 1, wherein said magnetically shielding structure comprises at least one layer of magnetic shielding material located on said first surface of said support body.

4. The printed circuit board of claim 1, wherein said magnetic material comprises MFe₂O₄, wherein M is at least one atom selected from the group consisting of Mn, Fe, Co, Ni, Cu, and Mg.

5. The printed circuit board of claim 1, wherein said magnetic material comprises a material which includes conductive particles.

6. The printed circuit board of claim 5, wherein said magnetic material comprises a material which includes nickel particles.

7. The printed circuit board of claim 5, wherein said magnetic material comprises a material which includes cobalt particles.

8. The printed circuit board of claim 5, wherein said magnetic material comprises a material which includes iron particles.

9. The printed circuit board of claim 1, further comprising at least one of said integrated circuits mounted on said support body.

10. The printed circuit board of claim 1, wherein said magnetic memory structure is a magnetic random access memory device.

11. The printed circuit board of claim 1, wherein said support body is a memory module support.

12. The printed circuit board of claim 11, wherein said memory module support has plug in connectors on at least one edge.

13. The printed circuit board of claim 1, wherein said magnetically shielding structure is patterned to underlie said locations for supporting said integrated circuits.

14. The printed circuit board of claim 1, wherein said magnetically shielding structure is patterned to be positioned over said locations for supporting said integrated circuits.

15. The printed circuit board of claim 1, wherein said magnetic material is selected from the group consisting of ferrites, manganites, chromites, and cobaltites.

16. The printed circuit board of claim 1, wherein said magnetically shielding structure coupled to said support body encloses a plurality of integrated circuits sensitive to external magnetic fields.

17. The printed circuit board of claim 16, wherein said magnetically shielding structure further comprises one or more separate layers of electrically non-conductive magnetic material formed under each of said integrated circuits.

18. A printed circuit board for supporting integrated circuits sensitive to magnetic fields, said printed circuit board comprising:

a support body for supporting at least one magnetic random access memory structure of said integrated circuits; and

a magnetically shielding structure coupled to said support body for shielding at least one surface of said integrated circuits supported on said support body, wherein said magnetically shielding structure comprises one or more separate layers of electrically non-conductive magnetic material, each of said layers coupled to a surface of said support body, said one or more separate layers forming a discontinuous shield for said integrated circuits.

19. The printed circuit board of claim 18, wherein said magnetic material comprises MFe₂O₄, wherein M is at least one atom selected from the group consisting of Mn, Fe, Co, Ni, Cu, and Mg.

20. The printed circuit board of claim 18, wherein said magnetic material comprises a material which includes conductive particles.

21. The printed circuit board of claim 20, wherein said conductive particles are selected from the group consisting of nickel particles, cobalt particles and iron particles.

22. The printed circuit board of claim 18, wherein said magnetic material is selected from the group consisting of ferrites, manganites, chromites, and cobaltites.

23. The printed circuit board of claim 18, wherein said magnetically shielding structure coupled to said support body encloses a plurality of integrated circuits sensitive to external magnetic fields.

24. A method of packaging a semiconductor device comprising:

electrically coupling at least one integrated circuit sensitive to magnetic fields to a printed circuit board, said printed circuit board having at least one surface containing locations for supporting said integrated circuit;

contacting at least one surface of said printed circuit board with a magnetically shielding material formed of one or more separate layers of electrically non-conductive material said one or more separate layers forming a discontinuous shield for said integrated circuit, said magnetically shielding material shielding at least one surface of said integrated circuit from external magnetic fields;

forming at least one layer of said magnetically shielding material embedded within said printed circuit board; and

mounting an integrated circuit chip of said integrated circuit on said printed circuit board, said integrated circuit chip containing a magnetic memory structure which may be affected by external magnetic fields.

25. The method of claim 24, wherein said act of contacting said printed circuit board with said magnetically shielding material includes shielding top and bottom surfaces of said integrated circuit with said magnetically shielding material.

26. The method of claim 24, wherein said magnetically shielding material comprises a magnetic material selected from the group consisting of ferrites, manganites, chromites and cobaltites.

27. The method of claim 24, wherein said magnetic material comprises MFe₂O₄, wherein M is at least one atom selected from the group consisting of Mn, Fe, Co, Ni, Cu, and Mg.

28. The method of claim 24, wherein said magnetic material comprises a material which includes conductive particles.

29. The method of claim 28, wherein said conductive particles are selected from the group consisting of nickel particles, iron particles and cobalt particles.

30. The method of claim 24 further comprising the act of patterning said magnetically shielding material to form a magnetically shielding pattern underlying said locations for supporting said integrated circuits.

31. The method of claim 24 further comprising the act of patterning said magnetically shielding material to form a magnetically shielding pattern overlying said locations for supporting said integrated circuits.

32. The method of claim 24, wherein said magnetic memory structure is a magnetic random access memory device.

33. The method of claim 24, wherein said magnetically shielding material encloses a plurality of integrated circuits sensitive to external magnetic fields.

34. The method of claim 33, wherein said magnetically shielding material further comprises one or more separate layers of electrically non-conductive magnetic material formed under each of said integrated circuits.