Recycling a slurry for reuse in chemical mechanical planarization of tungsten wafer: Effect of chemical adjustments and comparison between static and dynamic experiments
Effects of chemical additives in slurry on tungsten CMP (W-CMP). Experiments under static and dynamic conditions and results. Discrimination effects of chemistry on the mechanical removal of tungsten. Design of experiments methodology. Recycle polishing slurries to reduce consumables, the limitation of industrial water rejection and lower solid wastes.
a wafer surface (cm2)  angstrm aq. aqueous c concentration (moll?1) c0 initial concentration (moll?1) cmp chemical and mechanical polishing cufs post-filtrated and concentrated after used slurry cus concentrated after used slurry cvd chemical vapor deposition di. desirability (%) d0 defectivity (number of particles deposited on a wafer) doe design of experiments w tungsten weight loss (g) eq. equivalent (1 eq.=0.36mm) i or fe iron ferric nitrate in inches k rate constant for h2o2 decomposition (h?1) lp0 initial permeability (lh?1m?2bar?1) mwco molecular weight cut-off (kda) n number of experiments nu within wafer non uniformity (%) ox. ac. oxalic acid pat. patent pou slurry at point of use reference ? tungsten thin deposit layer density (kgm?3) rr dynamic removal rate (min?1) s membrane area (m2) sds sodium dodecyl sulfate srr static removal rate (min?1) surf. surfactants t time (minutes) t time (hours) tmp trans membrane pressure (bar) us used slurry w tungsten