集成电路制造过程中,基于工件旋转磨削原理的超精密磨削技术是硅片平整化加工和图形硅片背面减薄的重要加工方法,但磨削加工不可避免会在硅片的表面/亚表面产生损伤,研究磨削硅片的亚表面损伤分布对于分析硅片发生弯曲或翘曲变形的原因,确定后续工艺的材料去除厚度都具有重要的指导意义。采用角度截面显微观测法研究工件旋转法磨削硅片的亚表面损伤深度沿晶向和径向的变化规律及光磨对磨削硅片的亚表面损伤分布的影响。结果表明,无光磨条件下磨削硅片的亚表面损伤深度在整个硅片表面分布不均匀,亚表面损伤深度沿周向在〈110〉晶向处大于〈100〉晶向,沿径向从中心到边缘逐渐增大;光磨条件下磨削硅片的亚表面损伤深度在整个硅片表面几乎是均匀的,且光磨后的硅片亚表面损伤深度明显小于无光磨条件下硅片亚表面损伤深度。
During the integrated circuit manufacturing process, ultra-precision grinding based on the principle of wafer rotation grinding is an important method in flattening of silicon wafers and in back-thinning of the completed device wafers, but the surface/subsurface damage is generated inevitably in ground silicon wafers. The subsurface damage distribution in ground silicon wafer has great significance in analyzing the reason of wafer bow/warp and determining the wafer removal thickness of subsequent process. Using the angle cross-section microscopy, the subsurface damage distributions in different crystal orientations and radial locations of silicon wafers ground with wafer rotation grinding method are investigated, and the effect of spark-out process on the subsurface damage distribution is analyzed. The experiment results show that in the ground wafer without spark-out process, the subsurface damage depth in 〈110〉 crystal orientation is larger than that in 〈I00〉 crystal orientation and the subsurface damage depth increases along the radical direction from the centre to the edge; but in the ground wafer with spark-out process, the subsurface damage depths in different crystal orientations and radial locations are almost the same. And the subsurface damage depth in ground silicon wafers with spark-out process is significantly smaller than that without spark-out process.