PURPOSE: To provide a method for manufacturing a thin film transistor having a source electrode and a drain electrode of a high dimensional accuracy.
CONSTITUTION: A method for manufacturing a thin film transistor, in which a gate electrode 2, a gate insulating film 3 and an operating semiconductor film 4 are sequentially laminated in this order on a transparent insulating board 1 and a source electrode 7a and a drain electrode 7b are aligned to be disposed on the film 4 through an insulating film 5, comprises the steps of forming a metal film 7 on the film 4, forming a mask 8 covering source electrode and drain electrode forming regions in contact with the film 7, and removing the film 7 with the mask 8 used as a mask by dry etching. The method has the step of forming the electrodes 7a and 7b. In the dry etching, as etching gas, mixture gas of chlorine series gas containing chlorine atoms and helium gas is used, and a flow rate of the helium gas is increased larger than that of the chlorine series gas.
WATANABE KAZUHIRO
SOEDA SHINICHI
