NOVELTY - A polyimide thin film is cleaned. The film is pre-dried in vacuum condition to remove volatile substance in film. An aluminum back electrode is formed on polyimide thin film. A zinc oxide thin film buffer layer is formed on aluminum back electrode. A NIP amorphous silicon thin film is formed on buffer layer at specific sputtering conditions. An aluminum front electrode is formed on P-type film, and flexible amorphous silicon thin film solar battery is manufactured.    USE - Manufacture of flexible amorphous silicon thin film solar battery.    ADVANTAGE - The flexible amorphous silicon thin film having favorable flexibility and improved photoelectric conversion efficiency is manufactured by a simple method with high productivity.    DETAILED DESCRIPTION - A polyimide thin film as a flexible substrate is cleaned. The film is pre-dried in vacuum condition at 200-300 degrees C to remove volatile substance in film. An aluminum back electrode is formed on polyimide thin film. A zinc oxide thin film buffer layer is formed on aluminum back electrode. The temperature and vacuum degree of substrate are 200-300 degrees C and 10-3 to 10-4 Pa, respectively. The ratio of argon to oxygen is 15:0-35:0. The sputtering power, pressure and time are 80-150 W, 1 Pa and 1-2 hours, respectively. A N-type microcrystal silicon thin film is provided on buffer layer. The flow rate of phosphine and silicon hydride during formation of film is 20-40 sccm and 10-15 sccm respectively. The sputtering pressure and time are 1 Pa and 1-2 minutes, respectively. The radio frequency power is 80-150 W. The temperature of substrate is 180-240 degrees C. I-type amorphous silicon thin film is formed on microcrystal thin film with radio frequency power of 80-150 W, silicon hydride flow rate of 20-40 sccm, substrate temperature of 180-240 degrees C and sputtering time of 40-1 minutes. A P-type amorphous silicon carbide thin film is formed on I-type film with same radio frequency power, substrate temperature and sputtering pressure. The flow rate of boron hydride, methane and silicon hydride are 25 sccm, 35 sccm and 40 sccm, respectively. The sputtering time is 30 seconds to 1 minute. A NIP amorphous silicon thin film is formed on buffer layer. An aluminum front electrode is formed on P-type film, and flexible amorphous silicon thin film solar battery is manufactured.