铜互连线低压无磨料化学机械平坦化技术

Technology of Abrasive-Free Slurry for Copper Interconnections Chemical Mechanical Planarization at Low Down Pressure

摘要:

在低压无磨料条件下，利用碱性FA/O型螯合剂具有极强螯合能力的特性，对铜互连线进行化学机械平坦化，获得了高抛光速率和表面一致性。提出了铜表面低压无磨料抛光技术的平坦化原理，在分析了抛光液化学组分与铜化学反应机理的基础上，对抛光液中的主要成分FA/O型螯合剂、氧化剂的配比和抛光工艺参数压力、抛光机转速进行了研究。结果表明：在压力为6.34 kPa和抛光机转速为60 r/min时，抛光液中添加5%螯合剂与1%氧化剂(体积分数, 下同)，抛光速率为1825 nm/min，表面非均匀性为0.15

Abstract:

The characteristics of FA/O chelating agent with extremely strong chelating ability were used for the chemical-mechanical planarization of copper interconnection on the conditions of abrasive-free slurry and low down pressure to obtain a high polishing rate and a fine within-wafer non-uniformity (WIWNU). The planarization principle of the abrasive-free alkaline slurry technology of the copper surface at low down pressure was put forward. Based on the analyzing of the planarization principle and the chemical reaction mechanism in abrasive-free alkaline slurry at low down pressure the main ingredient and prescription of slurry(containing FA/O chelating agent and oxidizer ) and polishing technological parameter (pressure and speed) were investigated. The results indicate that the polishing rate can reach 1825 nm/min and WIWNU is 0.25 when the down pressure is 6.3 kPa, the polishing machine speed 60 r/min, the slurry contains 5vol% chelating agent and 1 vol% oxidizer.