Magnetic sidewalls for write lines in field-induced MRAM and methods of manufacturing them

• US 9,620,411 B2
• Filed: 03/24/2016
• Issued: 04/11/2017
• Est. Priority Date: 12/29/2010
• Status: Active Grant

• Current Assignee: III Holdings 1, LLC (Intellectual Ventures LLC)
• Original Assignee: III Holdings 1, LLC (Intellectual Ventures LLC)
• Inventors: Mani, Krishnakumar
• Primary Examiner(s): BERNSTEIN, ALLISON
• Application Number:
  US15/080,241
• Publication Number:
  US 20160240431A1
• Time in Patent Office: 383 Days
• CPC Class Codes: G11C 11/16 using elements in which the storage effect is based on magnetic spin effect
• CPC Class Codes: H01L 21/2855 by physical means, e.g. sputtering, evaporation H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/76816 Aspects relating to the layout of the pattern or to the size of vias or trenches layout of the interconnections per se H01L23/528; CAD of ICs G06F30/00
• CPC Class Codes: H01L 21/76879 by selective deposition of conductive material in the vias, e.g. selective C.V.D. on semiconductor material, plating plating on semiconductors in general H01L21/288
• CPC Class Codes: H01L 23/5226 Via connections in a multilevel interconnection structure
• CPC Class Codes: H01L 23/5283 Cross-sectional geometry
• CPC Class Codes: H10B 61/00 Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
• CPC Class Codes: H10B 61/20 comprising components having three or more electrodes, e.g. transistors
• 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 50/85 Magnetic active materials

Abstract

In one embodiment, there is provided a non-volatile magnetic memory cell. The non-volatile magnetic memory cell comprises a switchable magnetic element; and a word line and a bit line to energize the switchable magnetic element; wherein at least one of the word line and the bit line comprises a magnetic sidewall that is discontinuous.

Claims

1. A method for manufacturing a discontinuous magnetic sidewall of at least one of a word line and a bit line, the method comprising:

defining the at least one of the word line and the bit line;

depositing layers on the at least one of the word line and the bit line;

defining a magnetic sidewall;

protecting discontinuous portions of the defined magnetic sidewall, wherein non-protected portions define exposed portions; and

removing the exposed portions.

2. The method of claim 1, wherein said depositing layers is done by Physical Vapor Deposition (PVD).

3. The method of claim 1, wherein the at least one of the word line and the bit line is defined with assistance of a hard mask.

4. The method of claim 1, wherein the magnetic sidewall is defined by performing anisotropic etching of the deposited layers.

5. The method of claim 1, wherein the magnetic sidewall is defined by performing reactive ion etching of the deposited layers.

6. The method of claim 5, wherein said performing reactive ion etching of the deposited layers uses chlorine gas mixed with argon gas.

7. The method of claim 1, wherein the discontinuous portions are rectangular.

8. The method of claim 1, wherein the discontinuous portions have an aspect ratio of 1.

9. The method of claim 1, wherein the discontinuous portions have a thickness that is less than 10 nm.

10. The method of claim 1, wherein the layers comprise an inner layer, an outer layer, and a middle layer sandwiched between the inner and outer layers.

11. The method of claim 10, wherein the middle layer is magnetic.

12. The method of claim 10, wherein the inner and outer layers are non-magnetic.

13. A method for manufacturing a discontinuous magnetic sidewall of at least one of a word line and a bit line, the method comprising:

etching a groove in a dielectric layer;

depositing layers in the groove;

defining a magnetic sidewall;

protecting discontinuous portions of the defined magnetic sidewall, wherein non-protected portions define exposed portions; and

removing the exposed portions.

14. The method of claim 13, wherein said depositing layers is done by Physical Vapor Deposition (PVD).

15. The method of claim 13, wherein the magnetic sidewall is defined by performing anisotropic etching of the deposited layers.

16. The method of claim 13, wherein the magnetic sidewall is defined by performing reactive ion etching of the deposited layers.

17. The method of claim 16, wherein said performing reactive ion etching of the deposited layers uses chlorine gas mixed with argon gas.

18. The method of claim 16, wherein:

the layers comprise an inner layer, an outer layer, and a middle layer sandwiched between the inner and outer layers; and

the inner layer is left at a bottom of the groove after the magnetic sidewall is defined.

19. The method of claim 13, wherein the discontinuous portions are rectangular.

20. The method of claim 13, wherein the discontinuous portions have an aspect ratio of 1.

21. The method of claim 13, wherein the discontinuous portions have a thickness that is less than 10 nm.

22. The method of claim 13, wherein the layers comprise an inner layer, an outer layer, and a middle layer sandwiched between the inner and outer layers.

23. The method of claim 22, wherein the middle layer is magnetic.

24. The method of claim 22, wherein the inner and outer layers are non-magnetic.