Film patterning method, array substrate, and manufacturing method thereof

A film patterning method, comprising:

• applying photoresist on a film to be patterned;
• performing exposure and development on the photoresist, a region corresponding to a completely removed portion of the photoresist after the exposure and the development being a first region;
• post-baking the photoresist, so that the photoresist is melted and collapsed to change the region corresponding to the completely removed portion into a second region, the second region exposing the film, wherein the photoresist, after the post-baking, forms into a mask pattern;
• and
• patterning the film by using the mask pattern as a mask,
• wherein a size of the first region in a direction parallel to a plane where the film is located is a first size, a size of the second region in the direction parallel to the plane where the film is located is a second size, the second size is smaller than the first size, and a planar shape of the first region and the second region comprises at least one selected from the group consisting of a circle and a line.