CeO_(2)磨料在介质化学机械抛光及后清洗中应用的研究进展

Research Progress of Application of Ceria Abrasive in Chemical Mechanical Polishing and Post⁃cleaning of Dielectriclayer

氧化铈(CeO_(2))磨料在化学机械抛光(CMP)效率、选择性以及表面质量等方面的表现优异,是目前浅沟槽隔离和层间电介质CMP的主要磨料,如何提高二氧化硅(SiO2)介质抛光速率(MRR)并改善表面质量是目前的研究热点。增强CeO_(2)⁃SiO2间的相互作用会大幅加快介质的去除率,但Ce—O—Si化学键的形成会导致CMP后清洗工艺的难度加大,因此,晶圆表面残余CeO_(2)磨料的有效去除被广泛关注。本文概述了CeO_(2)在二氧化硅CMP及后清洗工艺中的应用研究进展,并对CeO_(2)磨料的附着、去除机理进行了归纳分析。重点综述了复合磨料对CMP性能的影响以及水抛光工艺、物理及化学等方法的清洗效果。同时,对氧化铈作磨料的STI CMP及后清洗工艺中所面临的问题进行了总结,以期为其提供有价值的思考。

Ceria(CeO_(2))abrasive generally has excellent performance in chemical mechanical polishing efficiency,selec⁃tivity and surface quality.It is the main abrasive for CMP of shallow trench isolation(STI)and inter⁃level dielectric(ILD).How to improve the material removal rate(MRR)of SiO2 dielectric and the surface quality is the research focus at present.En⁃hancing the interaction between CeO_(2)and SiO2 will greatly accelerate the material removal rate of dielectric.However,the for⁃mation of Ce-O-Si chemical bond will aggravate the difficulty of post CMP cleaning process.Therefore,the effective remov⁃al of residual ceria abrasive on the wafer surface has been widely studied.In this paper,the application and research status of CeO_(2)in silica CMP and post⁃cleaning process are summarized,and the adhesion and removal mechanism of ceria abrasives are analyzed.The influence of composite abrasives on CMP performance and the effect of cleaning methods such as water polishing process,physical and chemical cleaning are reviewed.At the same time,the problems to be further studied in the process of STI CMP with ceria abrasive and post⁃cleaning are prospected,in order to provide valuable thinking for its research and devel⁃opment.