Hello, that depends on the passivation cycle duration. The deposition rate is roughly about 30 nm/min (for a CHF3/CH4 plasma, depend. on process conditions). Dauksher et al. report a depo. rate of 120 nm/min for a C4F8 plasma (W.J. Dauksher et al., J. Microelctronic Engineering 57-58, pp 607-612 (2001) ). The polymer at the bottom gets completely removed during the etching cycle, while the film at the sidewall survives the etching cycle, although gets etched/sputtered at low rate. Therefore, the film thickness at the sidewalls accumulates during the various passivation cycles. A natural stop for the cumulative film thickness growth at the sidewalls is the undercutting depth: If the film is as thick as the size of the scallopes or ripples, it's no longer shadowed by the mask, hence subject of ion bombardement resulting in fast sputtering rate. In general, the film thickness may be between a few 10 nm up to ~100 nm, depending on your process conditions. The size of undercutting or of the scallopes/ripples can be considered as an upper limit. In the rare case that the deposition layer is thick enough (long passivation cycle duration), you can measure by SEM'ing the cross section of a profile. Best regards Burkhard Volland -----Ursprüngliche Nachricht----- Von: Shawn ZhangAn: mems-talk@memsnet.org Datum: Montag, 31. Mai 2004 19:46 Betreff: [mems-talk] Passivation layer thickness in DRIE >Dear Sir or Madam, >I want to know the general passivation layer (C4F8) thickness in DRIE. Is it several hundreds nanometer thick? Could you recommend the way to mesure the passivation layer thickness? Thank you very much for your help. >Regards, >Shawn >_______________________________________________ >MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list >options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk >Hosted by the MEMS Exchange, providers of MEMS processing services. >Visit us at http://www.memsnet.org/ >