INDIUM TIN OXIDE DRY-ETCHING USING HBR GAS FOR THIN-FILM-TRANSISTOR LIQUID-CRYSTAL DISPLAYS

The dry etching technique for indium tin oxide (ITO) films has been in vestigated using HBr gas with a conventional parallel-plate-type react ive ion etching apparatus in order to fabricate ITO fine patterns for thin-film transistor addressed liquid crystal displays (TFT-LCDs). Etc hing rates of amorphous ITO and poly-ITO were almost the same, unlike the case with ITO wet etching. This demonstrates that the ITO etching rate using HBr gas is independent of the film characteristics. A scann ing electron microscopy study of etched ITO films showed that the reac tion products were not deposited on the sample surface, although the r esist surface was roughened. Al films, which are the underlayers of IT O films for TFT-LCDs, were not etched by HBr gas only. Therefore, high ITO/Al selectivity can be obtained by HBr gas.