王庆伟1, 2，王辰伟1, 2，周建伟1, 2, *（1.河北工业大学电子信息工程学院，天津 300130；2.天津市电子材料与器件重点实验室，天津 300130）
摘要：对铜晶圆进行化学机械抛光(CMP)，溶液组成和工艺条件为：胶体二氧化硅(平均粒径85 nm)5%(质量分数)，30% H2O25 mL/L，胍离子(Gnd+，由碳酸胍GC 或盐酸胍GC 提供)适量，抛光压力5.2 kPa，抛头转速87 r/min，抛光盘转速93 r/min，抛光液体积流速300 mL/min，时间1 min。研究了抛光液中Gnd+浓度对铜去除速率的影响，通过电化学方法及X 射线光电子能谱分析了Gnd+在铜表面的作用机制，探讨了Gnd+对铜CMP 后表面粗糙度的影响机制。一方面，随抛光液中GC 浓度的升高，铜的去除速率增大，GC 浓度为80 mmol/L 时满足去除速率高于200 nm/min 的要求；另一方面，Gnd+的引入不仅加剧了铜晶圆表面的化学腐蚀，而且使抛光液在铜晶圆表面的接触角增大，铜晶圆抛光后表面粗糙度增大。
文章编号：1004 – 227X (2019) 03 – 0114 – 05
Effect of guanidine ion on chemical mechanical polishing of copper // WANG Qing-wei, WANG Chen-wei,ZHOU Jian-wei*
Abstract: Chemical mechanical polishing (CMP) of copper wafer was conducted in a solution containing colloidal silica with an average size of 85 nm 5wt.%, 30% H2O2 5 mL/L, and a suitable amount of guanidine ion (Gnd+, comes from guanidine carbonate or guanidine hydrochloride which were abbreviated as GC and GH respectively) at a pressure of 5.2 kPa, a rotation rate of polishing head 87 r/min, a rotation rate of polishing disc 93 r/min, and a volumetric flow rate of polishing solution 300 mL/L for 1 min. The effect of Gnd+ concentration in polishing solution on the removal rate of copper was studied.The mechanism of the action of Gnd+ on copper surface during CMP was analyzed by electrochemical method and X-ray photoelectron spectroscopy. The mechanism of the effect of Gnd+ on surface roughness of copper after CMP was discussed.On one hand, the removal rate is increased with the increasing of Gnd+ concentration in polishing solution, and meets the requirement of beyond 200 r/min when the Gnd+ concentration is 80 mmol/L; on the other hand, the addition of Gnd+ not only exacerbates the chemical corrosion of copper wafer surface, but also increases the contact angle between the polishing solution and copper surface, leading to an increase in surface roughness of the polished copper wafer.
Keywords: copper wafer; chemical mechanical polishing; guanidine ion; removal rate; surface roughness
First-author’s address: School of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300130, China