High Performance Etching of ITO Films by Inductively Coupled Plasma using HI

Abstract

The etching process of ITO (Indium Tin Oxide) is used to form pixel electrodes of the liquid crystal displays. Though the wet etching is the mainstream in ITO etching process now, the dry etching is needed as making the pixel minute. There are few reports which systematically examine the etching characteristics by using various etching gases though some methods are proposed as for the ITO dry etching. We paid attention to inductively coupled plasma (ICP) which easily obtained high-density plasma, and examined the etching characteristics of ITO films systematically used HI, HBr, HCl and Cl₂. As the result, ITO was able to be etched vertically without damaging the photoresist by using ICP of HI mixed with Ar.The damage to the photoresist was larger than that of HI in other etching gases. In addition, a high etch rate was obtained in HI compared with the case to use other etching gases. ICP used HI showed excellent characteristics in the dry etching of the ITO films.