A向蓝宝石晶片化学机械抛光研究

Study on chemical mechanical polishing of A-plane sapphire wafer

采用正交试验和单因素实验,研究了磨粒种类(包括SiO_(2)、Al_(2)O_(3)和CeO_(2))和抛光工艺参数(包括抛光压力、抛光盘转速和抛光液流量)对A向蓝宝石(1120)化学机械抛光(CMP)效果的影响。通过超精密分析天平计算材料去除率,原子力显微镜观察抛光表面形貌。结果表明:在A向蓝宝石晶片CMP抛光过程中,胶体SiO_(2)磨粒比Al_(2)O_(3)和CeO_(2)磨粒的抛光效果好。抛光工艺参数对A向蓝宝石材料去除率的影响程度主次顺序为抛光压力、抛光盘转速和抛光液流量。当抛光压力为14.5 kPa,抛光盘转速为80 r/min,抛光液流量为90 mL/min时,A向蓝宝石晶片抛光效果最优,材料去除率达到2 366 nm/h,表面粗糙度(Ra)为0.80 nm左右。

The effects of different abrasives i.e.SiO_(2),Al_(2)O_(3),and CeO_(2),and process parameters i.e.polishing pressure,disc rotation speed,and slurry flow rate on chemical mechanical polishing(CMP)of A-plane sapphire(1120)were studied by orthogonal test and single-factor experiments.The material removal rate was calculated by weighing method using an ultra-precision analytical balance,and the morphology of polished surface was observed by atomic force microscopy.The results showed that the CMP effectiveness of colloidal SiO_(2) abrasives was better than that of Al_(2)O_(3) and CeO_(2) abrasives for A-plane sapphire wafer.The effects of the said process parameters on the material removal rate in CMP of A-plane sapphire wafer were in the following descending order:polishing pressure>disc rotation speed>slurry flow rate.The polishing effectiveness was the best with a material removal rate of 2366 nm/h and a surface roughness(Ra)of about 0.80 nm at polishing pressure 14.5 kPa,disc rotation speed 80 r/min,and slurry flow rate 90 mL/min.