Coating method, coating apparatus and recording medium
A coating sequence includes supplying a resist liquid onto a wafer under a condition that a liquid puddle of the resist liquid is formed at a central portion thereof; supplying, while rotating the wafer at a first rotation speed where the liquid puddle stays at an inner side than an edge of the wafer, a diluting liquid and moving a supply position of the diluting liquid from an outside of the liquid puddle to an edge portion thereof; moving, after the moving of the supply position from the outside to the edge portion, the supply position from the edge portion to the outside while continuously rotating the wafer at the first rotation speed; and rotating, after the moving of the supply position from the edge portion to the outside, the wafer at a rotation speed higher than the first rotation speed to diffuse the resist liquid toward the edge.
1. A coating method, comprising:
(a) forming a liquid puddle of a processing liquid having viscosity ranging from 1000 cP to 7000 cP at a central portion of a surface of a substrate by supplying the processing liquid onto the surface of the substrate and, after a preset time, stopping the supplying of the processing liquid;
(b) after the forming of the liquid puddle of the processing liquid and after the stopping of the supplying of the processing liquid, starting to supply, while rotating the substrate at a first rotation speed set to allow the liquid puddle to stay at an inner side than an edge of the substrate, a diluting liquid to an outside of the liquid puddle and onto the surface of the substrate and moving a supply position of the diluting liquid from the outside of the liquid puddle to an edge portion of the liquid puddle such that the supplied diluting liquid directly contacts the liquid puddle;
(c) after the moving of the supply position of the diluting liquid from the outside of the liquid puddle to the edge portion of the liquid puddle, moving the supply position of the diluting liquid from the edge portion of the liquid puddle to the outside of the liquid puddle while continuing to rotate the substrate at the first rotation speed; and
(d) after the moving of the supply position of the diluting liquid from the edge portion of the liquid puddle to the outside of the liquid puddle, stopping the supplying of the diluting liquid and rotating the substrate at a rotation speed higher than the first rotation speed to allow the processing liquid to be diffused toward the edge of the substrate,
wherein the supplying of the diluting liquid is continuously performed from when the supplying of the diluting liquid is started in step (b) until the supplying of the diluting liquid is stopped in step (d).
2. The coating method of claim 1 ,
wherein the forming of the liquid puddle of the processing liquid at the central portion of the surface of the substrate comprises supplying, while rotating the substrate at a second rotation speed equal to or higher than the first rotation speed, the processing liquid onto the surface of the substrate under a condition that the liquid puddle of the processing liquid is formed at a first region including a rotation center of the substrate and the processing liquid is suppressed from adhering to a second region at an outer side than the first region,
the moving of the supply position of the diluting liquid from the outside of the liquid puddle to the edge portion of the liquid puddle comprises moving the supply position of the diluting liquid from the second region to an edge portion of the first region, and
the moving of the supply position of the diluting liquid from the edge portion of the liquid puddle to the outside of the liquid puddle comprises moving the supply position of the diluting liquid from the edge portion of the first region to the second region.
3. The coating method of claim 2 ,
wherein the rotating, after the moving of the supply position of the diluting liquid from the edge portion of the liquid puddle to the outside of the liquid puddle, of the substrate at the rotation speed higher than the first rotation speed comprises:
rotating the substrate at a third rotation speed which is higher than the first rotation speed and allows a mixed solution of the processing liquid and the diluting liquid to be diffused toward the edge of the substrate, and
rotating, after the rotating of the substrate at the third rotation speed, the substrate at a fourth rotation speed which is higher than the third rotation speed and allows the processing liquid to be diffused toward the edge of the substrate.
4. The coating method of claim 2 ,
wherein a supply of the diluting liquid onto a position at the inner side than the edge of the substrate is started before the moving of the supply position of the diluting liquid from the second region to the edge portion of the first region.
5. The coating method of claim 4 ,
wherein the supply of the diluting liquid is started after setting the rotation speed of the substrate to be a fifth rotation speed lower than the first rotation speed.
6. The coating method of claim 5 ,
wherein the substrate is rotated at the fifth rotation speed one or more rounds after the supply of the diluting liquid is started and before the moving of the supply position of the diluting liquid is started.
7. The coating method of claim 4 ,
wherein, after the moving of the supply position of the diluting liquid from the edge portion of the first region to the second region, the supply of the diluting liquid is stopped in a state that the supply position of the diluting liquid is located at the inner side than the edge of the substrate.
8. The coating method of claim 4 ,
wherein the supply of the processing liquid onto the surface of the substrate is started in a state that the surface of the substrate is dried, and the supply of the diluting liquid is started in a state that the second region is dried.