Laser direct write patterning technique of indium tin oxide film

Abstract

The circuit patterns of transparent conductive oxide films (TCO films) have widely formed using the traditional photolithography method. The indium tin oxide (ITO) films of flat panel displays are one of the TCO films and usually ablated using the wet etching, which is widely adopted in the semiconductor processing. However, the chemical wet etching techniques usually appear with more disadvantages in the procedure, including the chemical pollution, the under-cut effect, the swelling and the costly. Therefore, the dry etching would be replaced the photolithography procedures. The laser directing method is one of the dry etching techniques and could form the circuit pattern on the ITO glasses. Moreover, the laser directing techniques could flexibility make the circuit pattern in the TCO film and the substrate would be not eroded by the laser ablation. The investigation is interested in circuit patterning of glass substrate using the laser direct writing techniques to ablate the ITO films by a UV laser materials processing system. The UV laser is a third-harmonic Nd: YAG laser with a 355 nm of wavelength and the power is 1.0 W. In this paper, the ITO films are ablated by the UV laser materials processing system which used the different repetition rate and the feeding speeds of tables. The results of laser pattering of ITO films are measured using the optical microscope (OM) and the scanning electron microscope (SEM), and it indicates the repetition rate of laser would affect the width of line.