Patent attributes
Disclosed are a method and an apparatus for applying a liquid onto a substrate. The method for treating a substrate, the method includes: a liquid supplying step of supplying a treatment liquid for forming a liquid film on the substrate while rotating the substrate; and a liquid diffusing step of diffusing the treatment liquid discharged to the substrate by rotating the substrate, after the liquid supplying step. The liquid diffusing step includes: a primary diffusion step of rotating the substrate at a first diffusion speed; and a secondary diffusion step of rotating the substrate at a second diffusion speed, after the primary diffusion step. The second diffusion speed is higher than the first diffusion speed. Accordingly, the treatment liquid can be applied to the substrate again by performing the secondary diffusion step, making it possible to adjust the thickness of a photosensitive film.