Greetings May I suggest a little different less costly/ faster approach? I use a photo imagable PI with a wet etch process. We use this from< 1 micron to approx 50 micron. Take a look at the HD website The definition is very good. Regards Walter www.elume.com .. -----Original Message----- From: kris [mailto:crikxo@yahoo.com] Sent: Sunday, October 23, 2005 2:11 PM To: mems-talk@memsnet.org Subject: [mems-talk] Grass during polyimide etch Hello All, I have the problem of occurance of grass during polyimide etch in O2 plasma. The polyimide i hvae used was PI2611. I went with low power and low pressures for the O2 plasma etch. (100mT, 100W). Aluminum was used as a hard mask for the polyimide. After etching 15 microns of PI in O2 plasma, i have observed grass in the etched regions. I presume that the grass arised due to the Al sputtering during O2 plasma that deposited in the regions where the PI was supposed to be etched and finally causing the micromasking of the polyimide in these regions resulting in grass. Can somebody suggest me in eliminating the grass. I would appreciate your help. Thanks, Kris