Hello, It sounds like you have tried a "scribe and break" process. This is when you use a diamond tip to scribe the top surface of the silicon then apply pressure on the backside to break the cleave mark. It could be that the wafer is too stressed and not able to break properly. How is the wafer thinned to the 30µm thickness? The thinning process is critical to reduce the stress of the wafer. I would guess it was ground then lapped or polished. You can also use a dicing saw to cut he wafer to final substrate or die size. This uses a diamond blade to cut through the wafer, which is mounted on an adhesive tape or could be waxed onto another silicon wafer for better support. You can choose the blades specification to achieve the best cut quality. If you like I can supply you with the names of companies that perform dicing, grinding and scribing services. They could perform some test cuts to show you the results. Or if you are looking to cut your wafers in house I can also point you in the right direction. You can then decide what your best option is. Thank you, Mario Robles Tanaka Systems, Inc. 2577 Leghorn Street Mountain View, CA 94043 650-966-8001 ofc 650-966-1881 fax www.dicingblades.com -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Esteban Broitman Sent: Tuesday, April 15, 2003 8:57 AM To: mems-talk@memsnet.org Subject: [mems-talk] cleaving of ultra-thin Si wafers Does anybody know how to "cleave" ultra thin Si wafers? I need to cut, from ultra-thin (30 microns) Si wafers, substrates of ~ 10 x 20 mm. I tried to use different kind of diamonds, but I always have the same problem: the substrate is not more "flexible", if I try to bent it, it cracks in many parts. I suspect that I am generating defects during the cutting of the substrates that propagate during the bending. Any suggestion?. Thanks for the reply to my e-mail: broitman@andrew.cmu.edu E. Broitman ---------------------------------- Dr. Esteban Broitman Senior Research Associate Department of Chemical Engineering Carnegie Mellon University Pittsburgh, PA 15213 Phone: (412) 268-9537 FAX: (412) 268-7139 ---------------------------------- _______________________________________________ MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk Hosted by the MEMS Exchange, providers of MEMS processing services. Visit us at http://www.memsnet.org/