I am etching a microfluidics channel into Corning 2947 soda lime glass
using a 1:1 mixture of (BOE 6:1) : (BOE 10:1) from Baker.  The etch profile
is unpredictable, often with strange crystal-like bumps within the etched
channel.  These bumps are definitely glass, not salt.  No amount of rinsing
or cleaning removes it. Can anyone explain the strange etch phenomenon in
this picture?

http://neuron.chem.psu.edu/particulates_or_what.jpg

This channel was etched (unagitated) for 24 minutes in the above etch
mixture.  The depth of etch is ~10µm, and the crystal-looking features are
raised bumps, measuring up to 6-8µm in height.  I use a gold/chrome
sacrificial layer to mask the etch, and I am certain that all the
resist/masking was sufficiently removed where the bumps are before etching.
 Can anyone help?  I have asked everyone in our cleanroom, but nobody
knows.  They don't use soda lime.

Thank you for helping!

Drew Manica