DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain a reliable TFT by reducing contaminating impurities in the TFT, in a semiconductor device using the TFT.SOLUTION: A reliable TFT can be obtained by removing contaminating impurities on a surface of a film existing in the film of a TFT on a glass substrate by contacting acidic solution containing fluorine with a surface of the film and flowing the acidic solution in a fixed direction. The acidic solution is buffered hydrofluoric acid having mixing ratio 1:50 of hydrofluoric acid and ammonium fluoride by volume ratio.