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钌作为下一代14 nm超大规模集成电路阻挡层新材料,有着重要的研究意义,然而对阻挡层进行化学机械抛光时,由于Ru和Cu的化学性质与硬度均不相同,Ru和Cu很难达到适合的速率选择比。研究了在以NaClO为氧化剂时,磨料质量分数、pH值、NaClO溶液体积分数、FA/OⅠ螯合剂体积分数以及抗蚀剂BTA对Ru化学机械抛光的影响,同时研究了NaClO和FA/OⅠ螯合剂的协同作用对Ru和Cu的去除速率和电偶腐蚀的影响。实验结果表明,以NaClO为氧化剂时,随着pH值升高,Ru去除速率和静态腐蚀速率均随之升高,NaClO能够大幅度提高Ru和Cu的去除速率,FA/OⅠ螯合剂的加入能够小范围提高Ru和Cu的去除速率,同时FA/OⅠ螯合剂可以减缓Ru和Cu之间的电偶腐蚀,最终通过调节抗蚀剂的质量浓度,可以实现Ru和Cu速率可控,达到合适的速率选择比。
Ruthenium is of great significance as a new barrier material for the next generation of 14 nm VLSI devices. However, due to the different chemical properties and hardness of Ru and Cu, chemical mechanical polishing of the barrier layer makes Ru and Cu difficult to achieve Suitable rate selection ratio. The effects of NaClO as oxidant, abrasive mass fraction, pH value, volume fraction of NaClO solution, volume fraction of FA / OⅠ chelator, and chemical mechanical polishing (BTA) on Ru chemical mechanical polishing were investigated. The effects of NaClO and FA / The synergetic effect of mixture on the removal rate and galvanic corrosion of Ru and Cu. The experimental results show that with NaClO as oxidant, both the removal rate of Ru and the static corrosion rate increase with the increase of pH, NaClO can greatly improve the removal rate of Ru and Cu, the addition of FA / In a small area, the removal rates of Ru and Cu are increased. At the same time, the FA / OⅠ chelating agent can slow down the galvanic corrosion between Ru and Cu. Finally, by adjusting the mass concentration of the resist, the Ru and Cu rates can be controlled to reach the appropriate Rate selection ratio.