Assessment of the REWORK operating environment for color filter glass substrate process

• Main Authors: Hsu, Chih-Yi, 許志義
• Other Authors: Bai, Hsunling
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/11825231905415136211

碩士 === 國立交通大學 === 工學院碩士在職專班永續環境科技組 === 99 === Color filters are the key components in the TFT-LCD, and the glass substrate material has the highest share of the cost for manufacturing color filters. There are some defective glass substrate products being produced from the color filter production process, they can be reused through REWORK process thus effectively reduce the manufacturing costs and avoid directing scrap waste that pollutes the environment. However, the wet etching procedure is employed in the REWORK process which uses highly corrosive HCl liquid chemicals. Under poor machine equipment and environmental management conditions, the chloride ionic pollutants would emit to the clean room environment and cause equipment corrosion problem. Under worse cases, it could even result in harmful effects on the workers. This study intends to monitor the chloride ions emitted to the clean room environment from ITO (Indium Tin Oxide) REWORK process area. The chloride airborne molecular contamination in the air environment was sampled by impingers and then analyzed by an ion chromatographer. The results show that the chloride ion concentration was up to 54592 ppbv as measured from the exhaust pipe of the recycling-wash operation of ITO REWORK process. In the process bay area and under normal equipment operation, the chloride ion concentrations in the clean room air were measured to be in the range of 12~25 ppbv. In addition, during the preventive maintenance operation, the etch tank cover was opened and the chloride ion concentrations were increased to be in the range of 90~282 ppbv. According to the analysis of the samples, the measured chloride concentrations can be well below the published ambient standards of Labor Affairs. It can also be complied with the recommended standards of Semiconductor Equipment and Materials International for the flat panel display industry. But the cleanliness of equipment and its parts can still cause bad effects in the long run. There is no good alternative liquid for replacing the HCl chemical yet. Thus the selection of corrosive resisting material as well as proper inspection and cleaning frequency are both necessary to prevent the accumulation and corrosion of choride pollutants on the equipments.