Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "javaguy11111" <javaguy11111@...> wrote:
>
>  Are you trying to mount MEMs devices on a pcb or using a pcb for making MEMs devices?
> 

I am etching copper patterns which operate as the MEMS
(the field calls it MEMS although there's nothing mechanical).
I have pictures on my blog here,
http://88proof.com/synthetic_biology/blog/archives/280

The pictures show pretty poor etch results which 
I am trying to improve using the best SMT techniques first.
Pad size/spacing is 1mm x 1mm with 0.125mm gap, or smaller!

Other researchers in the field have made similar MEMS
on flexi boards.  I can list some interesting articles
if interested.  These boards move liquid droplets across
surfaces (even vertical surfaces).  Though this requires
maybe >+1000V.

Something tangentially interesting, some researchers used
an "aborted etch" method with multiple dips in etch and
multiple mask steps, to make copper traces of different 
heights.  Not useful for standard PCB however they were
able to use it as MEMS for nanoparticle separation.
They used ferric chloride as the etchant and found it 
to be a linear etch, so the copper "steps" could be 
precisely made.   These steps were 10um to 50um or 
something.



> 
> --- In Homebrew_PCBs@yahoogroups.com, "jc805sb" <jc805sb@> wrote:
> >
> > 
> > I am etching general pcb's and also etching pcb's 
> > for MEMS devices.  The MEMS uses copper pads as small as 
> > possible so I am attempting to get down to 0.125mm (0.005")
> > and am trying the laminator+toner transfer with treated
> > paper and "GreenTRF" process.  Others do this for SMT
> > according to online sources so I am hopeful it will work.
> >
>