AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP22
Etching Characteristics of Al-doped ZnO Thin Films in ICP Etcher

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: S.W. Na, Sungkyunkwan University, South Korea
Authors: S.W. Na, Sungkyunkwan University, South Korea
M.H Shin, Sungkyunkwan University, South Korea
Y.M. Chung, Sungkyunkwan University, South Korea
J.G. Han, Sungkyunkwan University, South Korea
J.-H. Boo, Sungkyunkwan University, South Korea
N.-E. Lee, Sungkyunkwan University, South Korea
Correspondent: Click to Email
Recently, the greatly increasing use of transparent conducting oxide (TCO) films such as indium tin oxide (ITO) for flat panel displays has promoted the development of inexpensive TCO materials including Al-doped ZnO (AZO). AZO films have high electrical conductivities as well as high optical transparencies. From the manufacturing viewpoint, TCO films should be easily etched in order to fabricate fine electrodes. Therefore, dry etch characteristics of ZnO and Al-doped ZnO films need to be investigated. In this study, etching characteristics of AZO thin films using inductively coupled plasma (ICP) etcher. AZO thin films with thickness of 300~400nm and different Al doping concentrations were prepared on wafer substrates by RF magnetron sputtering and photolithographic patterning of a positive photoresist mask (AZ7220) was followed. An rf power of 13.56MHz was applied to the top electrode coil to induce ICP. Bottom electrode power of 13.56MHz was applied to the substrate holder to induce self-bias voltage to the wafer. Plasma etching of AZO thin films was investigated by varying gas mixing ratio of Cl@sub2@/(Cl@sub2@+Ar) and CH@sub4@/(CH@sub4@+Cl@sub2@+Ar) chemistries, top electrode power, and bottom electrode power. Etch rate and profiles on different weight percent of AZO thin films were measured by the scanning electron microscopy (SEM). In order to understand the etching mechanism, optical emission spectroscopy (OES) and X-ray photoelectron spectroscopy (XPS) are used to investigate the chemical states of the etched surface with various gas mixing ratios. The etch rate was increased with increasing rf bottom power and top electrode power and the etch rate of >= 200 nm/min was achieved. From the various measurements, it was found that the addition of Cl@sub2@ and CH@sub4@ gases plays an important role in determining the etch arte. Etching characteristics of AZO films with different Al doping concentrations will be discussed in detail.