Hi all, I was thinking of a process which would involve a last step of HF wet etching to create 4 micron deep trenches in silicon. I'm not sure how long the photo resist can withstand the HF. The photo resist would be Shipley 1813. I could use BOE also instead of HF but that would take even longer. Has anyone does this before? Thank you -- Shweta Humad Office: (404) 385-4306/2400