Thin film forming method and forming device therefor

A method of forming a thin film, comprising:

• in an intermediate thin film forming step, sputtering a target comprising at least one type of metal to form an intermediate thin film comprising the metal or an incomplete reactant of the metal onto a substrate;
• in a film composition converting step, bringing the formed intermediate thin film into an active seed of a reactive gas mixed with an inactive gas having a chemically inactive property in such a manner that the intermediate thin film is reacted with the active seed of the reactive gas, and converted into a compound of the metal;
• and
• in an optical characteristic adjusting step,
• repeatedly conveying a substrate holder between a zone to perform the intermediate thin film forming step and a zone to perform the film composition converting step while controlling a conveying speed of the substrate holder for holding the substrate,
• repeatedly performing the intermediate thin film formation and the film composition conversion, and
• accordingly adjusting a film composition of a finally formed thin film to form the thin film having an optical characteristic value of a region where a hysteresis phenomenon occurs in which a change route of the optical characteristic value differs with a reactive gas flow rate in a case where a flow rate of the reactive gas is increased and a case where the flow rate is decreased.

A thin film forming apparatus comprising:

• a substrate holder which is disposed in a vacuum tank and which holds a substrate;
• a film formation process zone which is disposed in the vacuum tank and in which sputtering is performed with respect to a target comprising at least one type of metal to form an intermediate thin film on the substrate;
• a reaction process zone comprising an active seed generator for generating an active seed of a reactive gas, and disposed in the vacuum tank, in which the intermediate thin film is reacted with the active seed of the reactive gas to form a thin film;
• a partitioning mechanism for spatially separating the film formation process zone and the reaction process zone from each other;
• a substrate holder driver for driving the substrate holder in order to convey the substrate between a position facing the film formation process zone and a position facing the reaction process zone;
• and
• substrate holder conveying speed controller for controlling the substrate holder driver in a range configured to form the thin film having an optical characteristic value in a region where a hysteresis phenomenon occurs in which a change route of the optical characteristic value differs with respect to a reactive gas flow rate in a case where the flow rate of the reactive gas is increased and in a case where the rate is decreased.