高速全晶圆薄膜厚度均匀图像在CMP工艺快速评定中的应用

应用高速度、高点密度熏覆盖全晶圆的薄膜检测仪得到的膜厚均匀图像来对CMP工艺进行快速评定。高点密度、全晶圆的膜厚均匀图像能即时显现出CMP工艺中的非对称性膜厚均匀问题并为根源分析和工艺改进提供快速反馈。对一些用常规的稀疏抽样点薄膜测量方法难以检测到但常见的CMP工艺中导致非对称性膜厚均匀问题熏例如垫片异常熏抛光机头安装不当熏空白晶圆nanotopography等进行比较分析和探讨。

Rapid CMP Process Characterization Through Fast Full Wafer Film Thickness Mapping

A high density, full wafer film thickness mapping metrology tool (～30,000-pt/8"-wafer) is employed in a rapid CMP process characterization study to capture asymmetric polishing non-uniformity issues and provide fast feedback for root cause analysis and process correction. This study examined some of the common contributors to the asymmetric film non-uniformity, such as pad anomaly, improper carrier mount, and substrate nanotopography, etc, which are otherwise missed by a conventional sparse measurement. The visualization of whole wafer film thickness variation reveals the characteristic signature for each of the film non-uniformity case, thus providing real time feedback that permits the identification of the root cause for each failure case.