Polishing head, polishing apparatus and polishing method
In one embodiment, a polishing head includes an elastic film configured to form pressure rooms to which a pressure fluid is fed, and configured to press a substrate onto a polishing surface with a fluid pressure of the pressure fluid. The head further includes a first magnetic generator provided above a partition wall that separates the pressure rooms. The head further includes a second magnetic generator configured to form at least a portion of the partition wall or provided below the partition wall.
1. A polishing head comprising:
an elastic film configured to form pressure rooms to which a pressure fluid is fed, and configured to press a substrate onto a polishing surface by deforming the elastic film with a pressure of the pressure fluid, the pressure rooms being adjacent to each other in a first direction and expanding or contracting in a second direction that is perpendicular to the first direction due to the deformation of the elastic film;
a first magnetic generator provided above two of the pressure rooms and a partition wall that separates the two of the pressure rooms and outside the pressure rooms; and
a second magnetic generator configured to form at least a portion of the partition wall or provided below the partition wall,
wherein the first magnetic generator is an electromagnet configured to adjust a direction and an intensity of magnetic force that acts between the first magnetic generator and the second magnetic generator,
the second magnetic generator is a permanent magnet,
a pressure that presses the substrate includes a first pressure depending on the pressure of the pressure fluid fed to the pressure rooms and a second pressure depending on the magnetic force, a magnitude of the first pressure being larger than a magnitude of the second pressure, and
the elastic film comprises first portions that are positioned under the pressure rooms and a second portion that is positioned in a vicinity of the partition wall between the first portions, the first pressure mainly deforms the first portions out of the first and second portions, and the second pressure mainly acts to apply pressure to the second portion out of the first and second portions.
2. The head of claim 1 , comprising a plurality of electromagnets as the first magnetic generator and a plurality of permanent magnets as the second magnetic generator, the plurality of permanent magnets having magnetizations oriented to a same direction.
3. The head of claim 1 , wherein the second magnetic generator forms a portion of the partition wall and is provided below an elastic partition wall that forms another portion of the partition wall.
4. The head of claim 1 , wherein the second magnetic generator is an elastic magnet forming the partition wall.
5. The head of claim 1 , wherein the second magnetic generator is a rubber magnet provided in the elastic film below the partition wall.
6. The head of claim 1 , further comprising:
a third magnetic generator provided above an end portion of the elastic film; and
a fourth magnetic generator provided below the end portion of the elastic film.
7. The head of claim 6 , wherein the third magnetic generator is an electromagnet configured to control a direction and a magnitude of magnetic force acting between the third and fourth magnetic generators.
8. The head of claim 6 , wherein the fourth magnetic generator is a permanent magnet.
9. The head of claim 1 , wherein the partition wall, the first magnetic generator and the second magnetic generator have ring shapes.
10. The head of claim 1 , further comprising a pressure room formation member configured to form the pressure rooms together with the elastic film, having holes for feeding the pressure fluid into the pressure rooms, and provided between the partition wall and the first magnetic generator.
11. A polishing apparatus comprising:
a polishing table configured to retain a polishing pad; and
a polishing head configured to retain a substrate to press the substrate onto a polishing surface of the polishing pad,
the polishing head comprising:
an elastic film configured to form pressure rooms to which a pressure fluid is fed, and configured to press the substrate onto the polishing surface by deforming the elastic film with a pressure of the pressure fluid, the pressure rooms being adjacent with each other in a first direction and expanding or contracting in a second direction that is perpendicular to the first direction due to the deformation of the elastic film;
a first magnetic generator provided above two of the pressure rooms and a partition wall that separates the two of the pressure rooms and outside the pressure rooms; and
a second magnetic generator configured to form at least a portion of the partition wall or provided below the partition wall,
wherein the first magnetic generator is an electromagnet configured to adjust a direction and an intensity of magnetic force that acts between the first magnetic generator and the second magnetic generator,
the second magnetic generator is a permanent magnet,
a pressure that presses the substrate includes a first pressure depending on the pressure of the pressure fluid fed to the pressure rooms and a second pressure depending on the magnetic force, a magnitude of the first pressure being larger than a magnitude of the second pressure, and
the elastic film comprises first portions that are positioned under the pressure rooms and a second portion that is positioned in a vicinity of the partition wall between the first portions, the first pressure mainly deforms the first portions out of the first and second portions, and the second pressure mainly acts to apply pressure to the second portion out of the first and second portions.
12. The apparatus of claim 11 , further comprising a controller configured to press the substrate onto the polishing surface with the fluid pressure by feeding the pressure fluid into the pressure rooms, and configured to adjust a pressing pressure of the partition wall with magnetic force acting between the first and second magnetic generators.
13. The apparatus of claim 12 , wherein the controller adjusts a direction and a magnitude of the magnetic force by controlling a current applied to the first magnetic generator that is an electromagnet.
14. The apparatus of claim 11 , wherein the polishing head further comprises a pressure room formation member configured to form the pressure rooms together with the elastic film, having holes for feeding the pressure fluid into the pressure rooms, and provided between the partition wall and the first magnetic generator.