TOOL FOR ANNEALING OF MAGNETIC STACKS

• US 20150031146A1
• Filed: 03/19/2012
• Published: 01/29/2015
• Est. Priority Date: 03/19/2012
• Status: Active Grant

• Current Assignee: III Holdings 1, LLC (Intellectual Ventures LLC)
• Original Assignee: MagSil Corporation
• Inventors: Mani, Krishnakumar
• Granted Patent: US 9,713,203 B2
• Time in Patent Office: Days
• US Class Current: 438/3
• 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 at least one wafer in a single line within the heating chamber;

a heating mechanism configured to heat the at least one wafer; and

a magnetic field generator configured to generate a magnetic field whose magnetic field lines pass though the single line of wafers during a magnetic annealing process.

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 at least one wafer.

4. The tool of claim 3, wherein the grid is configured to heat a heating block which in turn transfers the heat to the at least one wafer.

5. The tool of claim 3, wherein the magnetic field generator comprises a plurality of elongate conductors configured to be energized to generate the magnetic field.

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

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

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

9. A method for annealing a magnetic stack, the method comprising:

modifying a thermal processor for semiconductor wafer processing by retrofitting a magnetic field generator thereto; and

performing thermal and magnetic annealing processes on the magnetic stack with the modified thermal processor.

10. The method of claim 9, wherein the magnetic field generator comprises a plurality of elongate current-carrying conductors.

11. The method of claim 9, wherein the magnetic field generator and a thermal heater of the thermal processor sandwich the magnetic stack.

12. 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 conductors configured to generate, during a magnetic annealing process, a magnetic field whose magnetic field lines pass though the plurality of wafers;

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

13. The tool of claim 12, wherein:

the heating mechanism comprises a grid of resistive conductors disposed along first and second directions; and

the grid is configured to heat the plurality of wafers.

14. The tool of claim 13, wherein the grid is configured to heat one or more heating blocks which in turn transfer heat to the plurality of wafers.

15. The tool of claim 12, wherein the heating chamber comprises a plurality of opaque quartz insulating walls.

16. The tool of claim 15, wherein the plurality of opaque quartz insulating walls comprise a glazed surface.

17. The tool of claim 12, 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.

18. The tool of claim 12, 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.

19. The tool of claim 12, further comprising an outer housing that defines an insulating chamber between walls of the heating chamber and the outer housing.

20. The tool of claim 12, wherein the heating chamber comprises a gas inlet and a gas outlet via which pressure within the heating chamber is configured to be controlled.