碱性纳米SiO_2溶胶在化学机械抛光中的功能

Function of nano-SiO_2 slurry for chemical mechanical polishing in alkaline media

纳米SiO2是一种性能优越的功能材料,化学机械抛光(CMP)过程的精确控制在很大程度上取决于对纳米SiO2功能的认识。但是目前对碱性纳米SiO2在CMP过程中的功能还没有完全弄清楚,探讨它在CMP中作用是提高CMP技术水平的前提。纳米SiO2溶胶的表面效应使其表面存在大量的羟基,在CMP过程中纳米SiO2表面羟基与碱反应生成硅酸负离子,硅酸负离子再与硅反应来降低纳米SiO2的表面能量,同时达到除去硅的目的。综上所述,碱性纳米SiO2在CMP的过程中不仅起到了磨料的作用,同时参加了化学反应,在此基础上提出了在碱性条件下纳米SiO2与硅的反应机理。

Nano-SiO2 is a kind of functional material which has superior performance.In order to achieve a highly reliable CMP process it is necessary to examine the function of nano-SiO2.However,at present the function of nano-SiO2 for chemical mechanical polishing process in alkaline media is not well understood yet.A definitive understanding of the function is thus important to enhancement of the CMP process.There is a large number of hydroxyl,which react with alkaline forming silicate anion,on the nano-SiO2 sol surface due to the surface effect.Then silicate anion reacts with silicon in order to decrease nano-SiO2 surface energy.Meanwhile the silicon is removed.As described above,it is anticipated that the nano-SiO2 during CMP process not only function as abrasive but also take part in the chemical reaction.The reaction mechanism for nano-SiO2 is proposed based on the characteristic of nano-SiO2 for chemical mechanical polishing in alkaline media.