Focus ring and manufacturing method therefor
There is provided a focus ring capable of preventing a part of a heat transfer sheet from adhering to and remaining on a mounting table. The focus ring is arranged to surround a periphery of a substrate mounted on the mounting table having a temperature control device. Further, the focus ring includes a flexible heat transfer sheet. Furthermore, the focus ring is in contact with the mounting table via the heat transfer sheet, and the heat transfer sheet has a contact surface in contact with the mounting table and an anti-adhesion layer formed on the contact surface.
1. A focus ring arranged to surround a periphery of a substrate mounted on a mounting table having a temperature control device, the focus ring comprising:
a flexible heat transfer sheet,
wherein the focus ring is in contact with the mounting table via the heat transfer sheet, and
the heat transfer sheet has a contact surface in contact with the mounting table and an anti-adhesion layer formed on the contact surface, wherein the anti-adhesion layer is located between said contact surface of the heat transfer sheet and a mounting surface of the mounting table,
wherein the anti-adhesion layer contains heat conductive particulates,
the heat transfer sheet is formed in an annular shape, and
the anti-adhesion layer is not formed on areas of said contact surface within at least about 1 mm from an inner periphery of the heat transfer sheet toward an outer periphery thereof, and within at least about 1 mm from an outer periphery of the heat transfer sheet toward an inner periphery thereof, in a radial direction of the annular shape of the heat transfer sheet, so that respective gaps are formed between said contact surface of the heat transfer sheet and the mounting surface of the mounting table at said areas where the anti-adhesion layer is not formed.
2. The focus ring of claim 1 , wherein the anti-adhesion layer is a part of the heat transfer sheet, and the anti-adhesion layer is formed by irradiating an ultraviolet ray to the contact surface to harden the contact surface.
3. The focus ring of claim 2 , wherein the anti-adhesion layer is formed by irradiating the ultraviolet ray having a wavelength of about 120 nm to about 400 nm at an illuminance of about 1 mW/cm 2 to 1000 mW/cm 2 such that a total irradiation amount is in a range from about 10 mJ/cm 2 to about 1,000,000 mJ/cm 2 .
4. The focus ring of claim 1 , wherein the heat conductive particulates contain boron nitride or graphite.
5. The focus ring of claim 1 , wherein the anti-adhesion layer contains heat conductive particulates, and
the anti-adhesion layer is formed by irradiating an ultraviolet ray to the contact surface to harden the contact surface.
6. The focus ring of claim 1 , wherein a width of the anti-adhesion layer in the radial direction is equal to or larger than about 50% of a width of the contact surface in the radial direction.
7. The focus ring of claim 1 , wherein an Asker C hardness of the heat transfer sheet is in a range from about 3 to about 60.
8. The focus ring of claim 1 , wherein a storage modulus of the heat transfer sheet at a temperature of about 25° C. is in a range from about 0.5 MPa to about 10 MPa.