Hi again.

I have actulally been doing some electroplating: Cu onto Al MEMS structures
although I am still not happy with the reliability/repeatability..

Electroplating onto enclosed surfaces (eg onto the insides of narrow
cylinders) is a problem since the ion current does not penetrate into the
cylinder, it is all "used up" by the surface close to the ends of the
cylinder (this is the traditional 'throw' problem). The traditional
macroscopic solution is to run an electrode down the centre of the
cylinder, but you can not do this. You could look at electroless plating
solutions which rely on local chemical activity and do not have the same
throw problems. You might, however, need to pump these solutions through
your microchannels.

What is your surface to be plated? Electroless systems typically replace
one metal with another (but I am not an expert on this).

>Hi,
>Could someone give me some information on limits of electroplating in MEMS
>devices. How thin layers can be deposited ? Can electroplating be used to
>put thim metal coatings on surfaces which are 'invisible' from the ouside
>(e.g. encapsulated microchannels) ?
>Thanks on foerhand for your replies !
>Wouter
>
>Wouter van der Wijngaart
>Kungl. Tekniska H gskolan      Tel:    +46 - (0)8 - 790 66 13
>S3, Elektrisk m tteknik        Fax:    +46 - (0)8 - 10 08 58
>100 44  Stockholm              Minicall:       +46 - (0)740 - 26 71 28
>Sweden                 e-mail: wouter@s3.kth.se
>http://www.s3.kth.se/instrlab/staff/wouterw.html
>
>
>



Dr Alan Wilson
Defence Science and Technology Organization, Australia
               on attachment to the
       Center for Integrated Systems, Room 206X,
   Stanford University, Stanford CA 94305-4075, USA.

E'mail: alan@sensors.stanford.edu  (alan.wilson@dsto.defence.gov.au)

Tel (+1 650) 725 4197  Fax (+1 650) 725 9020