硫化镉晶片抛光工艺研究

Investigation on the Polishing Process of Cadmium Sulfide Wafers

研究了硫化镉(CdS)晶片Cd面的化学机械抛光(CMP)工艺。采用硅溶胶抛光液和NaClO氧化剂,分别使用聚氨脂和磨砂革抛光垫进行粗抛和精抛实验,并研究了氧化剂掺入量、抛光转速、抛光压力等工艺条件对CdS晶片表面质量的影响。结果表明,在抛光液中氧化剂体积分数为6%左右、抛光盘的转速为90～100 r/min、压强为55～60 g/cm2条件下可得到平整度较好、表面缺陷低、表面粗糙度低的高质量抛光表面。金相显微镜和微分干涉显微镜下观测抛光片表面无划痕、无桔皮产生,原子力显微镜测试得到抛光后CdS晶片Cd面的表面粗糙度值仅为0.385 nm。

The chemical mechanical polishing （CMP） process for cadmium （Cd） surface of cadmium sulfide （CdS） wafer was studied. With the silica sol as the polishing slurry and NaCIO as the oxidant, the rough polishing and fine polishing experiments were carried out using polyurethane and nubuck polishing pads, respectively. The influences of the processing conditions of the oxi- dant amount, polishing speed and polishing pressure on the surface quality of CdS wafers were researched. The results show that the high quality polished surface with good flatness, low surface defects and low surface roughness was obtained under the conditions of the oxidant volume fraction of about 6% , the polishing speed of 90 - 100 r/min and the pressure of 55 - 60 g/cm^2. The polished surface without scratch and range peel was observed by the metallographic microscope and differential interference microscope. The AFM testing results show that the surface roughness value of the polished Cd-surface for CdS wafer is only 0. 385 nm.