Study on subsurface damage of wafer silicon containing through silicon via in thinning
Study on subsurface damage of wafer silicon containing through silicon via in thinning
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含硅通孔晶圆减薄过程中亚表面损伤研究
DOI：
10.1140/epjp/i2019-12591-4
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发表时间：
2019
影响因子：
3.4
通讯作者：
He Liping
中科院分区：
文献类型：
--
作者：
Xu Yixin;Wang Miaocao;Zhu Fulong;Liu Xiaojian;Liu Yuhong;He Liping
采用分子动力学模拟方法研究了不同加载条件下含硅通孔（TSV）硅片的减薄机理。纳米磨削过程是由刀具挤压引起的晶格滑移和畸变引起的。当研磨深度较低时，硅表面会出现非晶硅。当磨削深度达到1.5nm时，工件亚表面出现纳米孪晶缺陷。我们比较了Si-SiO2界面和硅内部缺陷的深度。结果表明，纳米孪晶向界面扩展，导致损伤加深。在40 ~ 100 m/s之间，提高磨削速度可以略微降低界面损伤深度，而硅内部缺陷主要受磨削深度的影响。在40 ~ 100 m/s的速度范围内，法向力和切向力均随速度的增加而减小。摩擦系数计算结果表明，磨削深度越大，摩擦系数越大。在40至100 m/s的速度范围内，较高的速度降低了金刚石磨料颗粒和工件表面的摩擦系数。最后根据实际接触面计算出接触应力。当深度为1.0nm时，接触应力最大，为11.99GPa。
Molecular Dynamics (MD) simulations are carried out to study the thinning mechanism of silicon wafer containing through silicon via (TSV) at different loading conditions. The nano-metric grinding process is explained by lattice slip and distortion induced by tool extrusion. When the grinding depth is relatively low, amorphous silicon will appear on the surface of the silicon. The nano-twin defects appear on the subsurface of the workpiece as the grinding depth reaches 1.5nm. We compared the depth of the defect at the Si-SiO2interface and inside the silicon. The results show that the nano-twins extend to the interface leading to a deeper damage. Between 40 and 100m/s, increasing the grinding speed can slightly reduce the depth of interface damage, while the defects inside the silicon are mainly affected by the grinding depth. Moreover, both normal and tangential force decrease with the increase of speed from 40 to 100m/s. The friction coefficient calculation results show that the larger the grinding depth, the larger the friction coefficient. Higher speeds reduce the friction coefficient of the diamond abrasive particles and the workpiece surface over the speed range from 40 to 100m/s. At last, the surface contact stress is calculated based on the actual contact surface. With the depth of 1.0nm, the contact stress is the largest,i.e.11.99GPa.