Multilayer structures for magnetic shielding

• US 7,795,708 B2
• Filed: 06/02/2006
• Issued: 09/14/2010
• Est. Priority Date: 06/02/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Katti, Romney R.
• Primary Examiner(s): Tran; Minh-Loan T
• Assistant Examiner(s): YEUNG LOPEZ, FEIFEI
• Application Number:
  US11/445,874
• Publication Number:
  US 20070278628A1
• Time in Patent Office: 1,565 Days
• Field of Search: None
• US Class Current: 257/659
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/49109 outside the semiconductor or solid-state body
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• 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 2924/0102 Calcium [Ca]
• CPC Class Codes: H01L 2924/15156 Side view
• CPC Class Codes: H01L 2924/16195 Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H05K 9/0075 Magnetic shielding materials
• CPC Class Codes: H05K 9/0088 comprising a plurality of shielding layers; combining different shielding material structure

Abstract

A magnetic shield is presented. The shield may be used to protect a microelectronic device from stray magnetic fields. The shield includes at least two layers. A first layer includes a magnetic material that may be used to block DC magnetic fields. A second layer includes a conductive material that may be used to block AC magnetic fields. Depending on the type of material that the first and second layers include, a third layer may be inserted in between the first and second layers. The third layer may include a non-conductive material that may be used to ensure that separate eddy current regions form in the first and second layers.

Claims

1. A magnetic shield for shielding a microelectronic device from magnetic field effects, the magnetic shield comprising:

a first magnetic shield; and

a second magnetic shield, wherein the first and second magnetic shields each comprise;

a first layer comprising a magnetic conductive material;

a second layer comprising a non-magnetic conductive material; and

a third layer comprising a non-conductive material, wherein the third layer is interposed between the first layer and the second layer, and

wherein the first and second magnetic shields are separated by the microelectronic device.

2. The magnetic shield as in claim 1, wherein the magnetic conductive material is a high permeability material selected from the group consisting of NiFe and NiMoFe.

3. The magnetic shield as in claim 2, wherein the first layer has a thickness that is greater than about 10 mils.

4. The magnetic shield as in claim 1, wherein the second layer has a thickness that is tailored to attenuate alternating current magnetic fields.

5. The magnetic shield as in claim 1, wherein the second layer comprises a strata of conductive layers, wherein the conductive layers are separated from each other by an non-conductive layer interposed between each layer of the strata of conductive layers.

6. The magnetic shield as in claim 1, wherein the non-magnetic conductive material comprises a conductor selected from the group consisting of Al, Cu, and AlCu.

7. The magnetic shield as in claim 6, wherein the second layer has a thickness that is greater than about 20 mils.

8. The magnetic shield as in claim 1, wherein the non-conductive material comprises at least one of an epoxy or a dielectric material.

9. The magnetic shield as in claim 1, wherein the non-conductive material comprises a ferrite material.

10. The magnetic shield as in claim 1, wherein the third layer is directly adjacent to the first layer and the second layer.

11. The magnetic shield as in claim 1, the microelectronic device comprises a magnetoresistive random access memory (MRAM) device.

12. A magnetic shield for shielding a microelectronic device from magnetic field effects, the magnetic shield comprising:

a first layer comprising a magnetic conductive material;

a second layer comprising a non-magnetic conductive material; and

a third layer comprising a non-conductive material, wherein the third layer is interposed between the first layer and the second layer, and wherein the first, second, and third layers form a magnetic shield layer adjacent to the microelectronic device, and

wherein the second layer comprises a strata of conductive layers, wherein the conductive layers are separated from each other by an non-conductive layer interposed between each layer of the strata of conductive layers.

13. The magnetic shield as in claim 12, wherein the magnetic conductive material is a high permeability material selected from the group consisting of NiFe and NiMoFe.

14. The magnetic shield as in claim 12, wherein the non-magnetic conductive material comprises a conductor selected from the group consisting of Al, Cu, and AlCu.

15. The magnetic shield as in claim 12, wherein the non-conductive material comprises at least one of an epoxy or a dielectric material.