Hi, >I am also trying to use HNA. I contacted with Shipley and they have >S1818 and S1827. Will they work as HNA mask and can you suggest a >receipt? In my experience, Shipley S1813 doesn't like HNA, even with a good hardbake. I often use a Cr/Au (10nm/300nm) onto silicon, with masks patterned using suitable Au and Cr etchants through a S1813 mask. I've successfully completed etchtimes of 30 mins without any loss of adhesion to give nice deep profiles. Rgds Jim *********************************************** Dr Jim Thorpe Research Fellow Institute of Microwaves and Photonics School of Electronic and Electrical Engineering The University of Leeds Leeds LS2 9JT United Kingdom Tel: +44 (0)113 233 2049 (Office) Tel: +44 (0)113 233 2084 (Lab) Fax: +44 (0)113 244 9451 ***********************************************