Hi Igor I may talk to Dr. Garry(Igor) Kroll from ENS ( Advanced Technology Plating ): Phone: 408- 496 0740. Regards. Dr. Vladimir Gelfandbein Nayna Networks, inc. -----Original Message----- From: mems-talk-admin@memsnet.org [mailto:mems-talk-admin@memsnet.org]On Behalf Of Igor Kadija Sent: Monday, January 21, 2002 10:52 AM To: mems-talk@memsnet.org Subject: Re: [mems-talk] very uniform surface of elctroplated Nickel ? sou zou wrote: >Hi folks ! > >I am looking for some advices to get a very uniform surface of nickel electroplated layers (especially on silicon). Through my bibliography research, it seems that the trick is mainly to get an uniform current density across the coated surface (parallel current lines). The problem is the resist pattern wich does'nt allow to obtain that kind of strictly vertical current lines. Does anyone has an ingenious idea or a good web address to help me overcoming such a problem, please ? > >Thank you in advance, > >sz > _________ Dear sz: I am affraid the answer to your question is not that simple. You may find some of the information related to this matter on our website www.fibrotools.com. Briefly (if possible), the current lines direction and density depend on electric field and the electrolyte composition. Electric field again depends on a number of factors including the resist pattern. Resist pattern may affect the field distribution by many ways including the sidewalls quality (vertical, slanted, rough, clean, contaminated etc.) and by the actual pattern design (sharp points, edges etc.). With vertical current lines you may still have the problem of current density distribution since the pattern design may generate the "edge effect" thus causing excess current density in some sites of your pattern. This may be overcome with corrections in design and/or also by introducing the so called "dummy sites" (pattern sections that are not functional). You may still have the problem of uneven nickel electroplate. Under same electric field the current density also depends on electrolyte composition especially additives. If your specific pattern combined with equipment utilized in electroplating do not result in providing a uniform distribution of electrolyte and byproducts to and from the electroplated sites, the current density may be affected. This effect will be stronger as the features in your pattern become finer. Finally, assuming you met the requirements for a uniform current distribution the nickel finish may still be "rough" (depending what you consider smooth). This will be determined by the selection of electroplating solution (type of additives), electroplating parameters (temp., current density, pH etc.) and the electroplating equipment. Sincerely, IK www.fibrotools.com _______________________________________________ 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.mems-exchange.org/