电火花线切割单晶硅变质层与裂纹分析

Analysis on Deterioration Layer and Cracks of Monocrystalline Silicon Cut by WEDM

以电火花线切割的单晶硅为研究对象,建立了传热学数学模型,利用ANSYS仿真软件进行模拟计算,得到了放电区域的瞬态温度场和应力场分布。对电火花线切割后的硅片表面沿纵向进行了分层择优腐蚀试验,观察腐蚀表面形貌沿纵向的变化情况,确定了变质层厚度,总结出了放电参数对硅片表面变质层厚度的影响规律,并与模拟计算结果进行了对比,证明了所建模型的正确性。研究结果表明:放电电压和脉冲宽度是影响变质层厚度的主要因素;出现在变质层中的裂纹会随着放电能量的增加而急剧扩展,能量增大到一定程度后可扩展至晶体区,可以认为此时裂纹的深度即是变质层厚度。

Using monocrystalline silicon cut by WEDM as the research object a diathermanous and mathematics model was establish.Analogue computation was carried out with ANSYS simulation software,and the distribution of transient temperature and stress field were obtained.Then a hierarchical preferential etch experiment along the vertical orientation of monocrystalline silicon surface cut by WEDM was carried out to observe the corrosion morphology changes,the thickness of the deterioration layer was determined.The law of the deterioration layer thickness affected by electrical parameters was summed up and comparing to the simulation results,the correctness of the model was proved.The results show that： discharge voltage and pulse width are main factors which affect the deterioration layer thickness;the crack appeared in the metamorphic layer will increase rapidly as the discharge energy increases,and even can be expanded to crystal zone when energy increases to a certain degree.At this point the depth of the crack can be regarded as metamorphic layer thickness.