单晶SiC化学机械抛光液化学反应参数研究

Study on Chemical Reaction Parameters of CMP Solution for Single-Crystal SiC

选择影响化学机械抛光化学反应速率的参数:催化剂浓度、氧化剂浓度、抛光液的pH值、抛光液温度等进行了试验,研究了它们对基于芬顿反应的单晶SiC化学机械抛光效果的影响规律。发现只有当H_2O_2浓度高于20%、Fe_3O_4浓度高于1.25%时,增大H_2O_2、Fe_3O_4浓度,材料去除率才会显著越高,此时材料去除速率由化学液腐蚀速度与磨料机械去除速度共同决定;低于此范围时由磨料的机械作用决定。温度升高会加速H_2O_2分解,抑制羟基自由基·OH的生成,减缓化学腐蚀,降低材料去除率。当Fe_3O_4浓度、H_2O_2浓度、pH值、抛光液温度分别为1.25%、15%、7、41℃时,化学腐蚀与机械去除的协调性及磨料的分散性较好,表面粗糙度最低;当它们分别为5%、25%、9.3、15℃时,材料去除率最高。

A iming at the CMP of single-crystal SiC based on Fenton reaction, parameters which observably affect the chemical reaction rate, such as the concentration of catalyst and oxidant, pH＇and temperature of solution were studied in it. Only when the concentration of oxidant H2O2 is above 20% and the concentration of catalyst Fe3O4 is higher than 1.25%, the material removal rate can be significantly improved by enhancing the concentration of H2O2 or Fe3O4. In this case, the material removal rate is synergistically determined by the combined effect of the chemical corrosion of salution and the mechanical removal of abrasive. The increase of temperature of CMP solution will accelerate the decomposition of H2O2, so the production of ＂OH will be restricted, then the chemical reaction rate and material removal rate will slow down. The lowest surface roughness can be obtained when the concentration of Fe3O4 is 1.25%, the concentration of H2O2 is 15%, the pH value of solution is 7 and the temperature is around 41℃. The highest material removal rate can be gained when the optimal parameters are 1.25% （Fe3O4）, 15% （H2O2）,pH7 and 15℃, respectively.