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As the fabrication technology used in FPDs(flat-panel displays) advances, the size of these panels is increasing and the pattern size is decreasing to the um range. Accordingly, a cleaning process during the FPD fabrication process is becoming more important to prevent yield reductions. The purpose of this study is to develop a FPD cleaning system and a cleaning process using a two-phase flow. The FPD cleaning system consists of two parts, one being a cleaning part which includes a two-phase flow nozzle, and the other being a drying part which includes an air-knife and a halogen lamp. To evaluate the particle removal efficiency by means of two-phase flow cleaning, silica particles 1.5 µm in size were contaminated onto a sixinch silicon wafer and a four-inch glass wafer. We conducted cleaning processes under various conditions, i.e., DI water and nitrogen gas at different pressures, using a two-phase-flow nozzle with a gap distance between the nozzle and the substrate.The drying efficiency was also tested using the air-knife with a change in the gap distance between the air-knife and the substrate to remove the DI water which remained on the substrate after the two-phase-flow cleaning process. We obtained high efficiency in terms of particle removal as well as good drying efficiency through the optimized conditions of the two-phaseflow cleaning and air-knife processes.

No abstract

In the present study, the effectiveness of tetramethyl ammonium hydroxide (TMAH) in removing benzotriazole (BTA) layer from Cu surface after chemical mechanical polishing (CMP) is evaluated through electrochemical impedance spectroscopy studies. Since the insitu electrochemical impedance spectroscopy (EIS) measurements could not be applied to characterize the cleaning process, ex situ EIS measurement is used in the present work. The impedance data is modeled by electrical equivalent circuit (EEC) analysis and the polarization resistance values are calculated. The BTA removal for various concentrations of TMAH is quantified from polarization resistance values. Contact angle, scanning electron microscopy and x-ray photoelectron spectroscopy measurements were also conducted to complement the studies. The results show TMAH is effective in removing the BTA layer and that when part of the BTA is removed, the residual BTA appear as nodules. Some of the native oxides and hydroxides on the Cu surface are also removed by TMAH. When the slurry contains 0.1% (wt) BTA, a minimum concentration of 0.5% (wt) TMAH and a minimum cleaning time of 60 s are required for complete removal of BTA from the Cu surface.