Patent ID: 7250248

Claim:
A method for forming a pattern that uses a photomask, comprising the steps of: a) forming a resist film on a substrate; b) irradiating the resist film with the exposure light via the photomask; and c) developing the resist film irradiated with the exposure light so as to pattern the resist film, wherein the photomask comprises on a transparent substrate: a semi-light-shielding portion having a light-shielding property with respect to the exposure light; a light-transmitting portion surrounded by the semi-light-shielding portion and having a light-transmitting property with respect to the exposure light; and a peripheral portion surrounded by the semi-light-shielding portion and positioned in a periphery of the light-transmitting portion, the semi-light-shielding portion and the light-transmitting portion transmit the exposure light in a same phase, the peripheral portion transmits the exposure light in a phase opposite to that of the semi-light-shielding portion and the light-transmitting portion, and is spaced apart from the light-transmitting portion by a predetermined distance, a surface of the transparent substrate in a formation region for the light-transmitting portion is exposed, a first phase shift film that transmits the exposure light in a phase opposite to that of the light-transmitting portion is formed on the transparent substrate in a formation region for the peripheral portion, the first phase shift film and a second phase shift film that transmits the exposure light in a phase opposite to that of the light-transmitting portion are laminated sequentially on the transparent substrate in a formation region for the semi-light-shielding portion, and a multilayered structure of the first phase shift film and the second phase shift film has a transmittance that allows the exposure light to be transmitted partially and transmits the exposure light in a same phase as that of the light-transmitting portion.