Tool for annealing of magnetic stacks
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.
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.