MEMS中基底和薄膜的CMP制造技术

Fabrication of substrate and film in MEMS using CMP

化学机械抛光(Chemical&Mechanical Polishing,CMP)工艺已运用于微机电系统(Micro-Electro-Mechanical System,MEMS)中,并逐渐成为研制高品质微纳器件不可或缺的一道关键技术。区域压力调整、抛光终点检测等技术已经引入到CMP工艺,确保片内不均匀性(Within-wafer Nonuniformity,WIWNU)小于5%,同时有效减小"蝶形"和"腐蚀"等抛光缺陷。CMP在MEMS领域中的运用工艺过程更为复杂,抛光对象更为多元,表面质量要求更高。结合硅、介质层、石英、锗、铂和聚合物等自行开发的CMP工艺以及抛光后清洗处理,详细讨论和阐述CMP工艺如何运用于MEMS领域。实验结果表明,采用CMP工艺,结合抛光液改进和兆声清洗,不仅可以实现薄膜的全局平坦化,而且可以获得高品质的超薄基底、无损的硬质应变薄膜和用于低温直接键合的表面粗糙度小于0.5nm键合表面。CMP技术是研制高品质的可应用于MEMS器件的基底和薄膜的有效手段。

The chemical and mechanical polishing （CMP） process has already been applied to micro-electro-mechanical systems （MEMSs）, and it has become an indispensable and key technology for developing high-quality micro- and nano-devices. The introduction of zonal backing pressure and end point detection during the CMP process can not only guarantee a within-wafer nonuniformity of less than 5 %, but it can also effectively minimize polish defects, including dishing and erosion. The application of CMP to MEMS is more challenging in terms of complexity, target selection, and surface quality, compared to its application to semiconductors. Together with the self-developed CMP process for silicon, dielectric layers, quartz, germanium, platinum, and polymers, the application of CMP technology in the MEMS field is discussed and elaborated in detail. The experimental results show that when the CMP process is combined with slurry improvement and megasonic cleaning methods, global film planarization is observed; moreover, a high-quality ultra-thin substrate, a hard free-damage strain film, and a bonding surface with a surface roughness of less than 0.5 nm for low-temperature direct bonding are obtained. CMP technology allows for the effective fabrication of a high-quality substrate and film for MEMS devices.