AZ 4620 at 3000 rpm is ~9 u.   Try 1500 rpm or so.

Jason Tauscher
Silicon Designs, Inc.
[email protected]
(425)391-8329


----- Original Message -----
From: Marc A. Unger 
To: 
Sent: Thursday, May 13, 1999 9:57 AM
Subject: Re: Rapid printing of high lines


>
> The mold can be made in less than a day, but the mask (for the
> photolithography) still takes time (a few days).  If there is a printer
> than can print ~10 um high lines, that would obviously a lot faster.  And
> why not prototype as fast as possible?
>
> We are already investigating the use of thick resist.  Anyone happen to
> know a set of conditions for patterning an AZ type resist at 10-20 microns
> thick?
>
> -Marc Unger
> [email protected]
>
> > One way to achieve this is to use a thick resist - something like AZ4620
> > (I thinks Shipley also makes a thick resist?).
> > This type of photoresist can be spun on with different thicknesses (up
to
> > 100um thick) by varying the rpm spin speed and time.  Therefore, you can
> > use the masks you already have and do not need to etch away the
> > substrate(unless you need deeper channels).  Another solution could be
to
> > use SU-8(the patternable one) which also has controllable thickness.
> >
> > Also, why do you say that the process is slow for prototyping?  It seems
> > that the mold can be made in less than a day(even with etching), and the
> > PDMS can be "molded" within a few hours.  Is this what you think is
slow?
> > Or is your etching taking a long time?  Le me know if you would like to
> > discuss this more.
> >
> > -Angela Rasmussen
> > The George Washington University
> > The Institute of MEMS and VLSI Technologies
> >
> >
> >  On Wed, 12 May 1999, Marc A. Unger wrote:
> >
> > >
> > > Hi There -
> > >
> > > We're doing some "soft" lithography - i.e. PDMS casts of Si molds.  Up
> > > until now, we've been patterning resist and doing bulk etching of Si
to
> > > make our molds.  This works fine, but it's kind of slow for
prototyping.
> > > Does anyone know a way to "print" a pattern 10-15 microns high
directly
> > > on a smooth substrate?  ("Smooth" is relative; things as rough as a
> > > overhead transparency will probably still work.)  It would be a bonus
if
> > > the process allows adjusting the height of the lines.
> > >
> > > By the way, laser printers and thermal transfer printers seem to make
lines
> > > about 5 microns high.  So if anyone knows a way to make a laser
printer
> > > or thermal transfer printer print twice or three times on the same
area,
> > > that might be worth a try, too.
> > >
> > > I will summarize replies back to the list.
> > >
> > > Thanks in advance,
> > >
> > > Marc Unger
> > > Caltech Applied Physics
> > > [email protected]
> > >
> > >
> >
> >
> >
>
>