Pattern Forming Method

The present invention is a pattern forming method includes steps of: forming a resist underlayer film by using a composition for forming a resist underlayer film on a substrate to be processed; forming a resist middle layer film on the resist underlayer film; forming a resist upper layer film on the resist middle layer film; forming a pattern in the resist upper layer film; transferring the pattern to the resist middle layer film; transferring the pattern to the resist underlayer film; forming the pattern in the substrate to be processed; trimming the resist underlayer film; and forming a staircase-shaped pattern in the substrate to be processed. The composition for forming a resist underlayer film contains a resin and an organic solvent. The resin represented by the following formula (1) is used. This provides: a pattern forming method capable of accurately forming a staircase-shaped pattern by using a composition for forming a resist underlayer film having excellent dry-etching resistance over conventional KrF resists and having excellent film formability and substrate adhesion.