A production worthy, Tungsten Chemical Mechanical Polish (CMP) process using a commercially available K103 slurry was developed, characterized, and tested for sub-0.35μm multilevel interconnect fabrication. The effects of pre-tungsten CMP process on tungsten polish are reported in detail. A head-to-head comparison of the optimized KIO3 process with the standard Fe(NO3)3 process is described. Critical CMP tool parameters (process and hardware) were flexed using statistically valid experimental designs. The advantages and disadvantages of a post tungsten polish, oxide buff, are discussed. Across-wafer non-uniformity, specifically the enhanced polish rate of tungsten at the wafer edge, was significantly reduced with the optimized process parameters and hardware setup. Also, an automated endpoint system was utilized and a set of robust endpoint algorithms were developed to minimize the amount of oxide loss during tungsten CMP processing. Finally, the positive effects of the optimized KIO3 tungsten CMP process on interconnect integration and die yield are reported.
Optimized alignment for chemical mechanical polishing has been studied in detail to ascertain the best overall overlay and process conditions. This paper describes the methodology of alignment mark design and testing in conjunction with chemical mechanical polishing optimization for technologies of O.35um and below. The planarization of the substrate material by CMP combined with asymmetric metal deposition can cause linear alignment displacement. This study investigated chemical mechanical polish slurry types, hardware configuration, and process variables on general alignment conditions. Further study on alignment mark designs and photolithography stepper settings are investigated on a subset of optimized chemical mechanical polish conditions. An alignment condition where the result of less than O.lOum(X+3 sigma) was obtained.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.