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论文类型：期刊论文

发表时间：2011-10-01

发表刊物：MACHINING SCIENCE AND TECHNOLOGY

收录刊物：SCIE、EI、Scopus

卷号：15

期号：4

页面范围：415-428

ISSN号：1091-0344

关键字：larger silicon wafer; laser cleaning; laser energy threshold model; micro-particles

摘要：High cleaning quality for silicon wafers without damage is a challenge in laser cleaning technologies. Laser cleaning of Al2O3 micro-particles, which are the main contaminants of silicon wafer lapping and polishing solutions used in industry, from silicon wafers was studied for determining laser energy for high efficient particle removal while not causing damage to the wafers. As the cleaning force is generated from laser-energy absorption and conduction of the wafer, heat-conduction model on silicon wafer was developed during laser irradiation using a finer finite element method, from which cleaning force exerting on the particles greater than the adhesion force between the particle and the substrate, but less than the wafer damage energy of laser input was determined. Calculations of the laser energy threshold values for both particle cleaning and wafer damage were conducted for silicon wafers of 200 mm in diameter and 0.2 mm in thickness, and they were found to be about 60 mJ/cm(2) and 320 mJ/cm(2), respectively. The laser energy threshold model was finally verified experimentally using a KrF Excimer laser and found to be in good agreement with the experimental data. With the cleaning parameters from the model, the cleaning efficiency of as high as 98% has been achieved.