【作者】 张平；

【导师】 李振华； 卞保民；

【作者基本信息】 南京理工大学 ， 光学工程， 2007， 博士

【摘要】 激光等离子体冲击波清洗是一项前沿性的表面吸附颗粒清除技术，该技术以清洗定位准确、可重复清洗、适用范围广等潜在优势丰富了干法清洗，为半导体工业加工中的基片、掩模板清洗提供了一种新的途径。本论文从理论和实验两方面对该技术中涉及到的气态介质中激光等离子体冲击波传播特性、颗粒移除机制、微米颗粒的移除实验及基片安全工作距离等作了较为系统深入的研究，取得以下创新性成果：提出“zig-zag”多光束偏转方法测量激光等离子体冲击波在常压和低压空气介质中的中近场传播；建立了实验装置，在一次实验中获得了同一激光等离子体冲击波的波前传播特性规律，为激光等离子体冲击波清洗颗粒的理论计算和寻找最佳工作压强提供了客观依据。基于颗粒吸附平面基片的JKR模型，从冲击波与颗粒作用角度出发，改进颗粒滚动模型，得到了基片上颗粒滚动移除的范围；进而针对滚动模型无法解释凹槽中的颗粒移除，提出了颗粒弹出机制，该机制合理解释了基片上吸附颗粒的移除且给出了颗粒弹出所需冲击波的最低阈值。对吸附有10μm、20μm标准聚苯乙烯颗粒的平面基片进行了清洗实验，发现颗粒清洗中冲击波阈值与弹出模型相对应，并研究了工作距离变化、能量变化、粒径变化对基片表面清洗效果的影响。针对激光等离子体冲击波清洗过程中的基片宏观和微观破坏，分别通过缩短工作距离和金属探针探测的方法进行了研究，发现了240mJ激光能量下基片宏观安全工作距离应大于0.50mm，并研究了等离子体外射带电粒子空间飞行距离变化规律。本论文的研究成果为激光等离子体冲击波清洗这一新兴技术的深入发展提供了有价值的参考。更多还原

【Abstract】 Laser-induced plasma shock wave cleaning technology is an advancing cleaning method for the removal of adhered particles on surface, which riches the dry cleaning method and provides a new way for wafers and masks cleaning in semiconductor industry fabrication depending on its potential advantages such as high accurate position, repeatability, comprehensive applicability. This paper studies the related fields both in theory and experiment such as: laser-induced plasma shock propagation characteristics in gas medium, particle removal mechanism, experiments on micron particle removal, and safety working gap of wafer, which is a systemic and profound research. The innovation achievements are listed as following:Present a new "zig-zag" multiple beam deflection method to study the laser-induced plasma shock waves propagation in the middle and near filed both in standard atmosphere and sub-atmosphere. Based on the experimental equipment, the propagation characteristics of the same laser-induced plasma Shockwave are obtained in one experiment, which provides the objective proof for the particle removal calculation and the research of optimal pressure of laser-induced plasma shock wave cleaning.Based on the JKR model of adhered particles, rolling removal model, setting out from the view angle of shockwave-particle interaction, is modified, which shows the removal range of the particles on wafer. Moreover, a new saltation removal model of particle is established due to the failed explain of rolling mechanism on the particle removal in groove, which gives a reasonable explain for particles removal on wafer and shows the minimum shockwave strength threshold of particle saltation model.Laser-induced plasma shock wave cleaning method is utilized to remove the 10μm and 20μm particles, in which the Shockwave threshold in particle cleaning corresponds to the saltation model. Moreover, the influences of working gap variation, energy variation, and particle diameter variation are also studied.As for the macroscoy and microscopy damage to wafer in cleaning process, varying working gap and probe detection methods are utilized respectively. The macroscopy safety working gap should be larger than 0.50mm with laser energy of 240mJ and the variation rule of flying distance of ejecting charged particles of plasma is also studied.The results of this paper can be a valuable reference to the further development of laser-induced plasma Shockwave cleaning.更多还原