Tool for annealing of magnetic stacks

• US 9,713,203 B2
• Filed: 03/19/2012
• Issued: 07/18/2017
• Est. Priority Date: 03/19/2012
• Status: Active Grant

• Current Assignee: III Holdings 1, LLC
• Original Assignee: III Holdings 1, LLC
• Inventors: Mani, Krishnakumar
• Primary Examiner(s): Nguyen, Hung D
• Application Number:
  US13/424,337
• Publication Number:
  US 20150031146A1
• Time in Patent Office: 1,947 Days
• Field of Search: 219635, 219601, 219653, 219638, 2194651, 2194431, 2194411, 219438, 219544, 219545, 219390, 438 3, 438795, 117 32, 117 34, 117 51, 117917, 118623, 118639, 118724, 118725
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/6719 characterized by the construction of the processing chambers, e.g. modular processing chambers
• CPC Class Codes: H05B 6/10 Induction heating apparatus, other than furnaces, for specific applications

Abstract

In one embodiment of the invention, there is provided a tool for annealing a magnetic stack. The tool includes a housing defining a heating chamber; a holding mechanism to hold at least one wafer in a single line within the heating chamber, a heating mechanism to heat the at least one wafer; and a magnetic field generator to generate a magnetic field whose field lines pass through the single line of wafers during a magnetic annealing process; wherein the holding mechanism comprises a wafer support of holding the single line of wafers between the heating mechanism and the magnetic field generator. The tool may be a rapid thermal processor retrofitted with the magnetic field generator.

Claims

1. A tool for annealing a magnetic stack, the tool comprising:

a housing defining a heating chamber;

a holding mechanism configured to hold a wafer within the heating chamber;

a heating mechanism configured to heat the wafer; and

a magnetic field generator including a plurality of elongated, parallel, current-carrying conductors that traverse a major surface of the wafer and generate a magnetic field whose magnetic field lines pass through the wafer and align a magnetic domain in the wafer in a direction that is parallel with the major surface of the wafer.

2. The tool of claim 1, wherein the heating mechanism comprises a grid of resistive conductors disposed along first and second directions.

3. The tool of claim 2, wherein the grid is configured to supply heat directly to the wafer.

4. The tool of claim 2, wherein the grid is configured to heat a heating block which in turn transfers heat to the wafer.

5. The tool of claim 2, wherein the grid and the magnetic field generator are disposed to sandwich the wafer between them.

6. The tool of claim 1, wherein the tool is a retrofitted thermal processor for a semiconductor wafer processor.

7. The tool of claim 6, wherein the retrofitted thermal processor is a rapid thermal processor.

8. A tool for annealing a magnetic stack, the tool comprising:

a housing defining a heating chamber;

a holding mechanism configured to hold a plurality of wafers in a single line within the heating chamber;

a heating mechanism including a grid of resistive conductors configured to heat the plurality of wafers; and

a magnetic field generator including a plurality of elongated, parallel, current-carrying conductors that traverse a major surface of each wafer of the plurality of wafers and generate, during a magnetic annealing process, a magnetic field whose magnetic field lines pass through the plurality of wafers and align a magnetic domain in each wafer of the plurality of wafers in a direction parallel with its respective major surface;

wherein the heating mechanism and the magnetic field generator are configured to sandwich the plurality of wafers between them.

9. The tool of claim 8, wherein the grid of resistive conductors are disposed along first and second directions.

10. The tool of claim 8, wherein the grid is configured to heat one or more heating blocks which in turn transfer heat to the plurality of wafers.

11. The tool of claim 8, wherein the heating chamber comprises a plurality of opaque quartz insulating walls.

12. The tool of claim 11, wherein the plurality of opaque quartz insulating walls comprise a glazed surface.

13. The tool of claim 8, further comprising:

a plurality of pins mounted to a pin support plate, wherein the plurality of pins are configured to receive and support a wafer including the magnetic stack; and

a lift configured to lower the pin support plate and the plurality of pins to place the wafer in close proximity to the heating mechanism.

14. The tool of claim 8, further comprising:

a heated block having a greater thermal mass than a wafer including the magnetic stack;

a plurality of pins extending through the heated block and mounted to a pin support plate, wherein the plurality of pins are configured to receive and support the wafer; and

a lift configured to lower the pin support plate and the plurality of pins to place the wafer in close proximity to the heated block.

15. The tool of claim 8, further comprising an outer housing that defines an insulating chamber between walls of the heating chamber and the outer housing.

16. The tool of claim 8, wherein the heating chamber comprises a gas inlet and a gas outlet via which pressure within the heating chamber is configured to be controlled.

17. The tool of claim 8, wherein the grid of resistive conductors is configured to directly heat the plurality of wafers.

18. A tool for annealing a magnetic stack of a wafer, the tool comprising:

a housing defining a heating chamber;

a holding mechanism configured to hold the wafer within the heating chamber;

a heating mechanism configured to heat the wafer; and

a magnetic field generator including a plurality of elongated, parallel, current-carrying conductors that traverse a major surface of the wafer and generate a magnetic field whose magnetic field lines pass through the wafer and provide a pinning layer of the magnetic stack with a common magnetic domain aligned in a direction parallel with the major surface of the wafer.

19. The tool of claim 18, wherein the heating mechanism comprises a grid of resistive conductors that are disposed along first and second directions and that are configured to supply heat directly to the wafer.

20. The tool of claim 19, further comprising:

a heating block positioned to transfer heat to the wafer;

wherein the grid is configured to heat the heating block which in turn transfers heat to the wafer.