US Patent 7947432 Pattern formation method

After forming a lower layer film, an intermediate layer film and a first resist film on a substrate, a first resist pattern is formed by performing first exposure. Then, after a first intermediate layer pattern is formed by transferring the first resist pattern onto the intermediate layer film, a second resist film is formed thereon, and a second resist pattern is formed by performing second exposure. Thereafter, a second intermediate layer pattern is formed by transferring the second resist pattern onto the intermediate layer film. After removing the second resist film, the lower layer film is etched by using the second intermediate layer pattern as a mask, so as to form a lower layer pattern.