Optimization of BEOL R&C monitoring macros for accurate representation of circuit performance

Abstract

R (line resistance) and C (coupling capacitance) parameters are among the critical parameter list or even wafer acceptance criteria in volume production. Process engineers rely on R and C monitoring macros to tune processes to meet targets and control specs. However, the performance and capability of the R and C macros are much impacted by their own design. Therefore, properly designed R and C monitoring macros to represent genuine R and C performance in the product are critical. In this study, we show R and C monitoring macros were designed to make sure the same metal density is implemented at the underlying metal layer (CA/CB level) and on-layer. Furthermore, the desired pattern density is desired to be set as representative of the prime die at areas of interest (for example, SRAM, logic/analog devices or other active circuits). Therefore, resulting metal line profiles are consistent and corresponding RC plots represent the genuine RC performance.