I had the same problem with the matrix. If you have polystring all the matrix
does is permanently engrave it. Try using ST-22 its a solvent.

-----Original Message-----
From: mhlisea@buphy.bu.edu
Subject: [mems-talk] wet etching for crosslinked PS

hi,anyone can give me suggestion how to remove crosslinked polystyrene
using wet etching or isotropic plasma etching? Is there any solvent which
can dissolve crosslinked PS?
I am using PS nanoporous template to build nanohouse:filling Au into
nanoporous and cover the surface as roof. The pore is 20nm in diameter and
spacing is 30nm and template thickness is 30nm. That is why it is
difficult to remove the crosslinked PS(the matrix) underneath the Au roof.