Josef, we used to deal with a similar problem by scribing silicon first, then dipping in LN2 (makes the polymer extremely brittle), and then breaking. Not elegant, but might work for you Mac McReynolds Process Development Manager Caliper Life Sciences 605 Fairchild Drive Mountain View, CA 94043-2234 Tel: 650-623-0710 Fax: 650-623-0521 Please Join us at LabFusion 2004 "From technologies to knowledge" June 12th - 16th in Boston www.labautomation.org/LF/LF04/index.htm and join us for a special Caliper evening Monday June 14th!