Improvement of ITO Etch Rate and Uniformity by enhanced-ICP Technique

초록

Indium-tin-oxide(ITO) is now being used widely as a transparent electrode with high optical trasmittance and excellent electrical conductivity. As the wet etch technique of ITO has several problems, such as isotropic etch profile and etch rate dependent film characteristics, dry etch technique has been applied to form ITO film-electrodes. Although the dry etch technique of ITO with organic gas chemistry provides good anisotropic etch profile, it has the problem of low etch rate. And as the size of applicable substrate, such as for the flat panel display(FPD), increases, the uniformity of etch rate on large area becomes one of the most important issues. Here, we report improved etch characteristics of ITO on large area by applying the 'Enhanced-ICP'(Inductively Coupled Plasma) technique with an appropriate design of experiment (DOE), based on Taguchi method, to obtain better etch rate with organic gases. The unit ICP antenna for large area plasma source is arrayed to form 2x2. The tech rate of ITO with E-ICP operation showed improvemint of about 50% than normal-ICP operation, as consistent to the previous report for the photoresist etch by E-ICP operation. A better etch uniformity is also obtained on 350x300mm substrate with E-ICP operation