H_2O_2基电解液的pH值对铜钌电偶腐蚀的影响

Effect of the pH Value of the H_2O_2-Based Electrolyte on the Galvanic Corrosion Between Copper and Ruthenium

研究了电解液pH值对Cu和Ru电偶腐蚀的影响,并对其控制机理进行深入的研究。选取H_2O_2作为Cu和Ru电化学电解液中的氧化剂和腐蚀剂,选用HCl和KOH溶液作为pH调节剂,采用动电位扫描这种电化学技术,表征金属铜钌表面的电化学反应。实验结果表明:在pH值低于7时,Ru在电解液中逐渐生成不溶的RuO_2·2H_2O和RuO_3,Cu仅发生腐蚀反应。在Cu和Ru的电偶腐蚀中,Cu作为阳极而加速溶解,影响器件的可靠性。在pH值高于7时,Ru可生成可溶的过钌酸盐,Cu表面含有一层致密的氧化层。在Cu和Ru电偶腐蚀中,Ru作为阳极而加速溶解,Cu得到了保护。在pH值为9时,Cu和Ru的腐蚀电位差最小为5 mV,因此在弱碱性阻挡层抛光液中可减少Cu和Ru之间的腐蚀电位差,有效抑制Cu和Ru之间电偶腐蚀现象的产生。

The influence of the electrolyte pH value on the galvanic corrosion between Cu and Ru was studied,and its control mechanism was researched.Selecting H_2O_2 as oxidant and etchant in Cu and Ru electrochemical electrolyte and using HCl and KOH solution as the pH regulator,the electrochemical reaction of the metal copper and ruthenium surface was characterized by the electrochemical potentiodynamic scanning technology.The experimental results show that when the pH value is less than 7,Ru in the electrolyte gradually generates the insoluble RuO_2·2H_2O and RuO_3,and the Cu only occurs corrosion reaction.In the galvanic corrosion of Cu and Ru with Cu as the anode,Cu dissolves acceleratively and influences the reliability of the device.When the pH value is higher than 7,Ru can generate the soluble ruthenium acid salt,there is a dense oxide layer on the Cu surface.In the galvanic corrosion of Cu and Ru with Ru as the anode,Ru dissolves acceleratively and Cu is protected.The minimum of the corrosion potential difference of Cu and Ru is 5 mV at the pH value of 9,therefore the corrosion potential difference of Cu and Ru is reduced in the weak alkaline barrier polishing liquid,the galvanic corrosion phenomenon between Cu and Ru is effectively restrained.