不同pH值下过氧化氢对Ru的CMP的影响

Effects of Hydrogen Peroxide on Chemical Mechanical Polishing of Ru Under Different pH Values

研究了以H_2O_2为氧化剂,不同的pH值(2,4,6,8,10)对Ru的去除速率(vRu)和静态腐蚀速率(vSER)的影响,同时用电化学的方法研究了H_2O_2和pH值对Ru表面的动态极化曲线的影响,利用原子力显微镜对每次抛光前后的微观形貌进行了观察。实验结果表明:随着pH值的逐渐增大,Ru的去除速率和静态腐蚀速率也会随之升高,碱性条件下的vRu和vSER明显高于酸性条件。当pH值为2时,Ru表面生成致密的钝化层,阻碍了化学作用,vRu(0.31 nm/min)和vSER(0nm/min)最低;当pH值为4和6时,会生成可溶性的RuO_4,提高了化学作用,vRu和vSER相对提高;当pH值为8和10时,生成RuO_4^(2-)和RuO_4^-化学作用明显,vRu和vSER显著提高;当pH值为10时,vRu(23.544 nm/min)和vSER(2.88 nm/min)最高。同时,随着pH值的逐渐增大,Ru表面的腐蚀电位(Ecorr)不断减小,腐蚀电流密度(Icorr)不断增大,当pH值为10时,Ecorr达到最低值(0.094 V),Icorr为最高值(1.37×10^(-3)A/cm^(-2))。

The effects of different pH values（2,4,6,8,10）on the removal rate of Ru（vRu）and static corrosion rate（vSER）with H2O2 as the oxidant were investigated.Meanwhile the effects of H_2O_2 and pH values on the dynamic polarization curves of the Ru surface were studied by the electrochemical method,and the micro morphologies of the surface before and after each polishing were observed by using the atomic force microscope（AFM）.The experiment results show that the removal rate（vRu）and static corrosion rate（vSER）increase with the increase of the pH value,and the vRuand vSERin the alkaline condition are significantly higher than those in the acidic condition.When the pH value is 2,a dense passivation layer is formed on the Ru surface to hinder the chemical action,and the vRu（0.31 nm/min）and vSER（0nm/min）are the lowest.When the pH values are 4 and 6,the production of the soluble RuO_4 in the reaction can improve the chemical effect,and the vRuand vSERare relatively increased.When the pH values are 8 and 10,RuO_4^（2-）and RuO_4^-are generated,the chemical effect is obvious,and the vRuand vSERincrease significantly.When the pH value is 10,the vRu（23.544 nm/min）and vSER（2.88 nm/min）are the highest.Meanwhile,the surface corrosion potential（Ecorr）of the Ru decreases and the corrosion current density（Icorr）increases with the increase of the pH value.When the pH value is 10,the Ecorrreaches the lowest（0.094 V）,and the Icorrreaches the highest（1.37×10^（-3）A/cm^（-2））.