兆声化学机械复合抛光及其抛光均匀性的实现

Realization of Polishing Uniformity in Megasonic Vibration Assisted Chemical Mechanical Polishing

在匹配层结构压电换能器的基础上,通过对兆声压电振子的振动模式进行控制,在横向尺度上实现了兆声抛光工具头振动振幅的均匀化,进而开展了有/无兆声作用下硅片的化学机械抛光实验.抛光后,无兆声作用硅片的表面粗糙度Ra均值达到0.072μm,兆声作用硅片的表面粗糙度Ra均值达到0.020μm.测量了被抛光硅片的平面度,相对于无兆声作用硅片的平面度的PV值28μm,兆声作用硅片PV值显著下降,为21μm.可见,相对于传统化学机械抛光,兆声化学机械复合抛光能够有效地改善原有抛光工艺,提高硅片抛光表面质量,实现其抛光均匀性.

To obtain the uniform vibration amplitude of megasonic polishing tools in transverse direction,the matching layer structure of megasonic polishing vibrator was adopted and the vibration mode of the piezoelectric vibrator was controlled. Silicon wafers were polished with megasonic vibration assisted chemical mechanical polishing（ MA-CMP） and traditional CMP respectively. Experimental results indicate that the surface roughness Rawas reduced from 0. 072 μm to 0. 020 μm in coarse polishing by using MACMP. And the PV value of flatness of silicon wafer is 21 μm and 28 μm with and without megasonic assistance,respectively. It is clear that the use of MA-CMP has the potential to facilitate better polished surface quality and polishing uniformity than using traditional CMP in the same situation.