| 摘要 |
PURPOSE: A method for manufacturing a thin film transistor(TFT) is provided to form a pattern having a superior profile by controlling an etch selectivity according to an etching area, and to prevent a short-circuit of a lower metal layer by using a dry-etching method. CONSTITUTION: A thin film transistor includes a gate electrode(72), a source/drain electrode composed of Mo, a semiconductor layer(76a) and an ohmic contact layer(78b) composed of n+ a-Si:H. The source/drain electrode and the ohmic contact layer except an upper portion of a back channel region of the semiconductor layer are plasma-etched to form the first source/drain electrode and the first ohmic contact layer. Only the upper portion of the back channel region of the semiconductor layer is opened. The source/drain electrode and the ohmic contact layer are simultaneously plasma-etched to form the second source/drain electrode and the second ohmic contact layer, so that an etch selectivity of the molybdenum to the impurity semiconductor material becomes higher than 10:1.
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