碱性抛光液对铜布线电特性的影响

随着互连电路的规模发展到亚微米级,互连延迟已经成为超过门延迟的重要因素。减小延迟在互连结构中是不可避免的问题。化学机械抛光是最适合在多层铜互连结构中达到平整化目的的手段。出于对整体过程的考虑,我们将考察化学机械抛光对铜晶圆片电特性的影响。在这篇文章中,我们将考察两种抛光液在化学机械抛光中的影响,一种抛光液是酸性抛光液,来自于SVTC,另一种是碱性抛光液,由河北工业大学提供的。着重考察了三个方面的特性,电阻,电容和漏电流。电阻测试结果显示,河北工业大学提供的抛光液抛光后,电阻更小。而被两种抛光液抛光后的电容则相差不多,电容值分别为1.2 E^-10F 和1.0 E^-10F。同样,河北工业大学提供的抛光液抛光后的漏电流是1.0E^-11A,低于SVTC提供的酸性抛光液。结果显示,河北工业大学提供的碱性抛光液会产生小的碟形坑和氧化物损失,优于SVTC提供的酸性抛光液。

Effect of alkaline slurry on the electric character of the pattern Cu wafer

As interconnect circuits are scaled down to deep submicron regime, the interconnect delay becomes increasingly dominant over intrinsic gate delay. It is inevitable to change the material of interconnections to reduce the RC delay time. Chemical mechanical polishing (CMP) is the most suitable approach towards using copper in a multilevel metallization scheme. For process integration considerations, we will investigate the impacts of CMP on electrical characteristics of the pattern Cu wafer .In this paper, we investigate the impacts of the CMP process with two kinds of slurry, which one is acid slurry of SVTC and the other is FA/O alkaline slurry purchased from Tianjin Jingling Microelectronic Material Limited. There are three aspects investigated, resistance , capacitance and leakage current .The result shows that after polished by the slurry of FA/O, the resistance is lower than the SVTC. After polished by the acid slurry and FA/O alkaline slurry, the difference of capacitance is not very large. The values are 1.0 E-10F and 1.2 E-10F respectively. The leakage current of film polished by the slurry of FA/O is 1.0E-11A, which is lower than the slurry of SVTC. The results show that the slurry of FA/O produced less dishing and oxide loss than the slurry of SVTC.