摘要
硅片表面纳米级污染颗粒的检测与去除是集成电路制造(Integrated Circuit,IC)的关键环节.本文主要对纳秒级脉冲激光作用至硅片表面后纳米颗粒的动力学过程及颗粒成分在线检测方法进行了研究.搭建了双脉冲激光测量实验系统,并通过实验对300 nm Cu颗粒进行了双脉冲激光实验观测,通过分析表征颗粒运动轨迹的击穿光谱特征,从实验上观测到了清洗激光作用后颗粒沿垂直硅片表面向上的运动轨迹.在综合考虑空气碰撞阻力、颗粒重力的影响下,建立了激光清洗后颗粒的运动模型,并与实验相结合求解了运动模型参数,计算获得了清洗激光作用后颗粒的初始速度和激光作用时间内颗粒的平均加速度.本文为激光诱导晶圆表面纳米颗粒去吸附以及激光至纳米颗粒动力学过程研究提供了一种模型方法,也为集成电路污染源在线检测提供了一种重要方法.
Nano-scale particle stripping and inspection on silicon wafer are critical issues for Integrated Circuit(IC)manufacture industry. As more new materials are used in IC manufacture, not only particle itself but also its composition should be inspected. Particles are mainly adhered by the van der waals force. One of potential particle desorption method is laser cleaning which is environment friendly. However, the mechanism of laser cleaning is not clear and more studies should be done for laser ablation. In this paper, the kinetic process of nano particle on silicon wafer induced by nanosecond pulsed laser as well as the on-line detection method of particle composition were studied. A potential method of nano particle dynamic analysis and particle composition inspection were presented. A dual nanosecond pulse laser system both wavelengths at 532 nm is designed in which one laser pumps the particles away from wafer surface almost without damage, the other laser breakdowns the particles in air above the wafer surface to obtain the emission lines of the contaminated particles of 300 nm Cu by a spectroscopy with CCD. Particle motion trail in z direction was observed after laser cleaning by analyzing particle spectral features. The particle dynamic model after stripping was established in which the resistance of air collision and gravity were included. And the model parameters were obtained by calculation using experimental results. The initial velocity of particle at the end of laser pulse and the average acceleration during laser interaction were calculated which were 7.6 m/s and 7.6 × 108 m/s2 respectively. The sensitivity of the dual laser system was evaluated which was between 2.1 × 1013 to 5.1 × 1013 atoms/cm2. As result, it is found that the gravity of the particle should not be ignored and the velocity divergence between different stripping particles is existed. The study not only provides a methodology for the study of laser-induced removal of nano particles on the wafer surface and laser induced nano particl
作者
刘立拓
王春龙
余晓娅
石俊凯
黎尧
陈晓梅
周维虎
Liu Li-Tuo;Wang Chun-Long;Yu Xiao-Ya;Shi Jun-Kai;Li Yao;Chen Xiao-Mei;Zhou Wei-Hu(Institute of Microelectronics,Chinese Academy of Sciences,Beijing 100094,China;Liberation Army 32180,Beijing 100012,China;Key Laboratory of Experimental Physics and Computational Mathematics,Beijing 100094,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第16期158-165,共8页
Acta Physica Sinica
基金
国家自然科学基金(批准号:61404171)
国家重点研发计划(批准号:2019YFB2005600)资助的课题。
关键词
纳米颗粒运动模型
激光诱导击穿光谱
激光清洗机理
成分检测
dynamic model of nano particle
laser induced breakdown spectroscopy
laser cleaning
composition inspection
