Method of fabricating bottom gate type organic thin film transistor

A method of fabricating a bottom gate type organic thin film transistor, the method comprising the acts of:

• forming a gate conductive layer pattern on a substrate;
• forming a gate insulating layer on an exposed portion of the surface of the substrate and the gate conductive layer pattern;
• forming source/drain electrodes on the gate insulating layer to expose a portion of the surface of the gate insulating layer above on the gate conductive layer pattern;
• forming an organic semiconductor thin film on the exposed portion of the surface of the gate insulating layer;
• forming on the organic semiconductor thin film a passivation layer pattern exposing a portion of the surface of the organic semiconductor thin film;
• and
• forming an organic semiconductor thin film pattern by etching the exposed surface of the organic semiconductor thin film using the passivation layer pattern as an etch mask,
• wherein the passivation layer pattern is composed of a mixture in which a lubricant oil is mixed with a polymer comprising rubber, rubber of isoprene group, or rubber of butylene group or an organic melted in the lubricant oil are mixed.