Implementation of CoWP metal caps into Cu/low-k integration schemes requires a wet stripper that not only gives efficient cleaning but also has good compatibility to CoWP and low-k dielectrics. This paper describes a novel non-fluoride CoWP compatible stripper, developed based on a systematic study of the effect of stripper components, i.e. solvent, corrosion inhibitor, and stripper pH. Electrochemical methods were used to characterize galvanic corrosion of the CoWP/Cu couple and to estimate CoWP etch rate. Our studies showed that a traditional fluoride stripper caused severe damage to CoWP capping layer. The new stripper achieved a good balance between cleaning efficiency and compatibility to CoWP and low-k dielectrics, and demonstrated significant advantages in electrical properties over the traditional fluoride stripper. © 2009 Elsevier B.V. All rights reserved.
Wu, A., Baryschpolec, E., Rao, M., Schaller, M., Bartsch, C., Leppack, S., & Ott, A. (2010). Development of compatible wet-clean stripper for integration of CoWP metal cap in Cu/low-k interconnects. In Microelectronic Engineering (Vol. 87, pp. 1685–1688). https://doi.org/10.1016/j.mee.2009.11.048