InSb晶片化学抛光研究

Study of Chemical Polishing of InSb Wafers

机械抛光会给InSb晶片表面造成一定程度的机械损伤,增加表面的粗糙度,从而影响器件的性能。化学抛光可以有效地去除表面划痕,改善晶片的表面形貌,降低粗糙度。用低浓度的溴-甲醇溶液对机械抛光后的InSb晶片进行了化学抛光,并对化学抛光前后的InSb晶片进行了表面形貌、总厚度偏差(TTV)、粗糙度、表面组分和杂质对比分析。实验结果表明,用低浓度的溴-甲醇溶液对InSb晶片进行化学抛光,腐蚀速率平稳且容易控制,能有效去除表面划痕,从而得到光滑、平坦的表面。晶片表面的粗糙度为6.443nm,TTV为3.4μm,In/Sb原子比接近1。与传统的腐蚀液CP4-A、CP4-B相比,用低浓度的溴-甲醇溶液对InSb晶片进行化学抛光,可以获得更低的表面粗糙度和TTV,且In/Sb的原子比更接近于1。

Mechanical polishing can result in mechanical damage at the surface of an InSb wafer to a certain extent, increase the ＇surface roughness of the wafer and affect the performance of the final device. However, chemical polishing can remove the surface scratch of the wafer and decrease the surface roughness. The InSb wafer is polished mechanically and further polished with a low concentration Br2- MeOH solution. The morphology, total thickness variation （TTV）, roughness, surface composition and impurity of the polished and unpolished InSb wafers are compared. The result shows that when the InSb wafer is polished with a low concentration Br2-MeOH solution, the erosion rate is stable and can be controlled easily and the surface scratch can be removed effectively and hence a flat mirror-like surface can be obtained. The chemically polished wafer has its surface roughness of 6.443nm, a TTV of 3.4~rn and an atomic ratio of In/Sb close to unity. Compared with the traditional CP4-A and CP4-B etching solution, the low concentration Br2-MeOH solution is more suitable for polishing the InSb wafers chemically.