Coating film forming method and coating film forming apparatus

1. A coating film forming method, comprising:

holding a substrate by a substrate holder;

forming an air flow on a front surface of the substrate by exhausting an atmosphere around the substrate;

supplying a coating liquid configured to form a coating film on the front surface of the substrate;

forming, after moving a covering member configured to cover the substrate from a first position to a second position relative to the substrate on which the coating liquid is supplied, the air flow in a gap formed by the covering member placed at the second position and the front surface of the substrate being rotated at a first rotation number such that a flow velocity of the air flow becomes larger than a flow velocity of the air flow obtained when the covering member is placed at the first position; and

rotating the substrate at a second rotation number higher than the first rotation number to adjust a film thickness distribution of the coating film by throwing the coating liquid off from a peripheral portion of the substrate,

wherein the covering member is an annular member formed along a circumference of the substrate,

the annular member includes an annular first portion whose circumferential edge is located at a position closer to a central portion of the substrate than a circumferential edge of the substrate or is located to face the peripheral portion of the substrate; and an annular second portion facing a region of the substrate inwardly positioned from the peripheral portion, and

a height from the substrate to the first portion is larger than a height from the substrate to the second portion.

2. The coating film forming method of claim 1 ,

wherein the forming of the air flow in the gap comprises forming the air flow such that drying of the coating film is slower at the peripheral portion of the substrate than at a portion of the substrate more centrally located than at the peripheral portion.

3. The coating film forming method of claim 1 ,

wherein the supplying of the coating liquid comprises rotating the substrate at a third rotation number larger than the first rotation number to diffuse the coating liquid supplied on a central portion of the substrate toward the peripheral portion thereof.

4. The coating film forming method of claim 1 ,

wherein the rotating of the substrate at the second rotation number is performed in a state that a gap formed between the front surface of the substrate and the covering member is larger than the gap in the forming of the air flow in the gap or in a state that the covering member is retreated from above the substrate.

5. The coating film forming method of claim 1 ,

wherein the first rotation number is in a range from 10 rpm to 500 rpm.

6. The coating film forming method of claim 1 ,

wherein the second rotation number is equal to or larger than 1000 rpm.

7. The coating film forming method of claim 1 ,

wherein the substrate on which the coating liquid is supplied has an irregularity pattern formed on the front surface thereof.

8. A coating film forming method, comprising:

holding a substrate by a substrate holder;

forming an air flow on a front surface of the substrate by exhausting an atmosphere around the substrate;

supplying a coating liquid configured to form a coating film on the front surface of the substrate;

forming, after moving a covering member configured to cover the substrate from a first position to a second position relative to the substrate on which the coating liquid is supplied, the air flow in a gap formed by the covering member placed at the second position and the front surface of the substrate being rotated at a first rotation number such that a flow velocity of the air flow becomes larger than a flow velocity of the air flow obtained when the covering member is placed at the first position; and

rotating the substrate at a second rotation number higher than the first rotation number to adjust a film thickness distribution of the coating film by throwing the coating liquid off from a peripheral portion of the substrate,

wherein a diameter of an outer circumference of the covering member is smaller than a diameter of the substrate such that the covering member does not cover a peripheral edge of the substrate.

9. The coating film forming method of claim 8 ,

wherein an opening is formed at a central portion of the covering member, and

a diameter of the opening is in a range from 30 mm to 80 mm.

10. The coating film forming method of claim 8 ,

wherein the forming of the air flow in the gap comprises forming the air flow such that drying of the coating film is slower at the peripheral portion of the substrate than at a portion of the substrate more centrally located than at the peripheral portion.

11. The coating film forming method of claim 8 ,

wherein the supplying of the coating liquid comprises rotating the substrate at a third rotation number larger than the first rotation number to diffuse the coating liquid supplied on a central portion of the substrate toward the peripheral portion thereof.

12. The coating film forming method of claim 8 , wherein the rotating of the substrate at the second rotation number is performed in a state that a gap formed between the front surface of the substrate and the covering member is larger than the gap in the forming of the air flow in the gap or in a state that the covering member is retreated from above the substrate.