Al合金在碱性条件下CMP研究

Research of Aluminum Alloy CMP under Alkaline Condition

Al化学机械抛光是实现28 nm高k金属栅器件集成电路的关键制程,采用田口方法设计正交实验,主要研究了碱性抛光液对Al合金抛光特性的作用。围绕抛光液组分进行实验。结果表明,有机胺碱体积分数为1.5%,螯合剂体积分数为0.5%,硅溶胶磨料体积分数为15%,活性剂体积分数为0.3%,氧化剂H2O2体积分数为1%时表面粗糙度最低,同时抛光液组分中活性剂体积分数在化学机械抛光过程中对Al合金表面粗糙度影响最为显著。通过优化抛光液组分配比,化学机械抛光后Al合金表面粗糙度可降到1.81 nm(10μm×10μm)。在最佳配比,即pH值为10.51时的抛光液与传统三酸抛光液进行对比实验,Al表面粗糙度明显低于传统三酸抛光液,抛光后Al表面无划伤、无蚀坑,达到了较好的抛光效果。

Aluminum chemical mechanical polishing （CMP） is the key process to achieve the 28 nm high-k metal gate device integrates. Using Taguchi method to design the orthogonal experiment, the role of alkaline slurry on aluminum polishing characteristic was mainly studied. The result shows that when the volume fraction of alkali organic amine is 1.5% , the volume fraction of chelating agent is 0.5% , the volume fraction of silica abrasive is 15% , the volume fraction of active agent is 0. 3% , the volume fraction of oxidant H2 02 is 1% , the surface roughness is the lowest. At the same time, the volume fraction of the surfactant in the polishing slurry significantly affects the surface micro roughness aluminum alloy during the CMP. By optimizing the polishing slurry ratio of composition, the surface micro roughness of aluminum alloy can efficiently down to 1.81 nm （ 10μm×10μm） post CMP. In the best proportion the pH value of polishing slurry is 10.51, compared with traditional three-acid-type polishing slurry, the surface micro roughness of aluminum is lower than the traditional three-acid-type polishing slurry, and after the CMP a good polishing effect of aluminum with no scratches and no corrosion pit is achieved.