Yield improvement for displays’ color filters surface by establishing a precision reclaim-module

Abstract

An effective surface micromachining process for yield improvement was developed using microelectromechanical etching as a precision reclaim-module for indium tin oxide (ITO) thin-film nanostructures from the displays’ color filter surface of thin film transistor liquid crystal displays (TFT-LCDs). The low yield of ITO thin-film deposition is an important factor in optoelectronic semiconductor production. By establishing a recycling process using the ultra-precise removal of thin-film nanostructures, the optoelectronic semiconductor industry can effectively recycle defective products, minimizing both production costs and pollution. For the etching-process, an adequate gap-width between the negative-electrode and the ITO surface, a high flow velocity or a higher working temperature of the electrolyte, results in a higher removal rate for ITO thin-films. Also, adequate feed rate of the workpiece (displays’ color filter) combined with enough electrical power produces a fast removal rate. Pulsed direct current can improve the effect of dregs discharge and is advantageous to associate with the fast feed rate of the workpiece, but it raises the current rating. A smaller edge radius and a small width of the negative-electrode provide a larger discharge space and better etching effect. Microelectromechanical etching requires only a short period of time to remove the ITO thin-film easily and cleanly.