James, It is pretty typical to have problems removing wafers from the platen of an Autoetch or Rainbow system when the chamber is vented. The service techs will tell you to put a small fragment of vinyl glove, cleanroom wipe, or a similar object on the platen when you are aligning the transport system at atmospheric pressure, to prevent wafer breakage from stiction. The stiction problem should not be too acute with the chamber under vacuum, however. I had a similar problem on my 490 when one lift pin got partially pulled out, so it contacted the wafer before the other 3. You might try aligning all four lifter pins with a wafer and a small bubble level. Make sure the leveling of the wafer when lifted is the same as the leveling on the platen. Having all 4 hit at the same time seems to help spread the force over the whole wafer rather than at one single lift point. The pins are simply pressed into holes in the lifter assembly, so you can pull them straight out with a pliers, and push them back in the same way. Just raise the lifter pins in the Macro page, and push or pull them into the holes in the platen until everything is level. It wouldn't hurt to check the tips of the pins either to see if they are pointy or rounded off. They should be flat at the top, without any kinks or bends. I have successfully run thin quartz wafers without breakage in our machine, and they seem to break if you barely touch them. Lam Research does not support this etch platform any more, but Aspect Semiquip in Phoenix, AZ (USA) provides good support and spares. http://www.aspectsys.com No relationship, but I have been pretty happy with them so far. Al Raisanen Rochester Institute of Technology -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of James Dekker Sent: Thursday, March 20, 2003 9:21 AM To: mems-talk@memsnet.org Subject: [mems-talk] LAM etcher troubles We are using a somewhat dated Lam etcher (autoetch 490) as an oxide etcher and it has developed a peculiar problem. Occasionally, (and it is more frequent than desired) it will break SOI wafers. The best diagnosis seems to be that the wafers are sticking to the platen. This sticking problem happens to both double side polish (DSP) and SSP SOI wafers, and also to non-SOI dummy wafers. However, the thin (380 um) SOI seem to be weaker and so they break when the lifting fingers try to raise the wafer from the cathode. (we have manually unloaded some wafers after etching and it takes quite a bit of effort to pry them from the cathode). Has anybody encountered this before and is a solution known? Thanks James Dekker, Research Engineer VTT Microelectronics Research center Tekniikantie 17, Espoo P.O.Box 1208, FIN-02044 VTT, FINLAND _______________________________________________ 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/