STUDY OF PROCESS IMPACT ON K VALUE OF LOW K DIELECTRIC MATERIAL USED IN CU / LOW K DUAL DAMASCENE INTERCONNECT

Abstract

This project evaluated the baseline unit process step and the impact on the dielectric k value of CoralTM was evaluated using IME Cu interconnect process tools and analysis techniques. Secondly, the process conditions at key unit process steps and their impact on k value were evaluated. Furthermore, additional process treatment and their impact on k value were also evaluated. The measurements from the mercury probe had acceptable variation which was less than 1.6% within a period of three weeks. The next two experiments showed that soft O2 recipe followed by soft forming gas recipe produced a lower dielectric constant. However, the dielectric constant was increased after cleaning. The in-situ and non-in-situ ashing experiment showed that in-situ soft O2 recipe followed by soft forming gas recipe produced a lower dielectric constant. The plasma treatment study showed that the etching recipe without any plasma treatment produced a lower dielectric constant. The polymerisation study showed that the recipe with higher concentration of polymerisation gas produced a lower dielectric constant. Lastly, the standard recipe for metal 2 produced a lower dielectric constant after etching and stripping, but the standard recipe for SiC layer produced a lower dielectric constant after cleaning.