METHOD FOR MANUFACTURING THIN-FILM TRANSISTOR, METHOD FOR MANUFACTURING TFT SUBSTRATE, AND METHOD FOR CLEANING SUBSTRATE

PROBLEM TO BE SOLVED: To provide a method for manufacturing a thin-film transistor capable of reducing particles to adhere in a drying step, a method for manufacturing a TFT substrate, and a method for cleaning a substrate.SOLUTION: A method for manufacturing a thin-film transistor includes the steps of: forming gate electrodes 13a and 13b above a substrate 11; forming a gate insulating layer 14 above the gate electrodes 13a and 13b; and forming a contact hole 14H by removing a part of the gate insulating layer 14. The step of forming the contact hole 14H further includes the steps of: exposing the gate insulating layer 14 and developing it with a developer; removing the developer by cleaning a surface of the gate insulating layer 14 with a cleaning liquid composed primarily of an amphiphilic solvent; arranging a liquid-repellent solution showing a liquid repellent property to the surface of the gate insulating layer 14 on the gate insulating layer 14 after the developer removing step; and removing the liquid-repellent solution from the gate insulating layer 14 using gravity applied to the liquid-repellent solution and/or inertial force.