You can buy premix etch from Transene Company, I recommend that you dilute
the etch in the bottle 5 parts water to 1 part etch. It etches fast lots of
lateral under cut. The best way to etch is on a spray etcher.

Rick

Rick Morrison
Radant Mems Inc.
255 Hudson Road
Stow Ma, 01775
Tel- 978-562-3866
EMAIL  rmorrison@radanttechnologies.com