不同晶粒尺寸和晶向分布多晶硅片弯曲应力的有限元模拟

摘要

The photoluminescence (PL ) technology was used to identify the crystal orientation of the polycrystalline silicon wafer, the elastic modulus of polycrystalline silicon wafer in different orientations was measured through the nano-indentation experiment.The finite element program was used to establish the polycrystalline silicon wafer finite element model containing the information of grain size and grain orientation,and then the elastic modulus got from the nano-indentation experiment were inputted to the model to obtain the bending strength of polycrystalline silicon wafer with different grain sizes and grain orientation distributions;the simulation results were verified by three-point bending experiment.The results show that elastic modulus and hardness of polycrystalline silicon wafter in different grain orientation distributions are different.The maximum bending stress value and the maximum stress position of the polycrystalline silicon wafer are affected by crystal orientation distribution.Grain shapes will affect the maximum bending stress.Reducing the grain size can reduce the maximum bending stress.The model’s correction is verified by the three-point bending experiment.%采用光致发光晶向识别技术分辨多晶硅片晶向的分布情况，通过纳米压痕试验测试多晶硅片在不同晶向上的弹性模量；然后利用有限元方法建立包含晶粒尺寸和晶向分布信息的多晶硅片有限元模型，将纳米压痕试验测得的不同晶向的弹性模量带入此模型，模拟得到了不同晶粒尺寸和晶向分布下多晶硅片的弯曲应力，最后通过三点弯曲试验对模拟结果进行了验证。结果表明：多晶硅片在不同晶向上的弹性模量和硬度不同；晶向分布会影响多晶硅片的最大弯曲应力和最大挠度的位置，晶粒形状会影响多晶硅片的最大弯曲应力；减小晶粒尺寸可以降低多晶硅片的最大弯曲应力；三点弯曲试验验证了所建模型的正确性。