Hello everyone,

     I'm currently working on process development for a multilayer
     microwave integrated circuit. My final metallization layer is
     aluminum, and I would like to minimize undercutting, so I am
     considering a Barium Chloride type of dry etching procedure,

     However, I recently learned about the ion-milling technique. It claims
     to have virtually no undercut, and high yields. A careful choice of
     photoresist must be made as the process generates much heat.

     Anyone have any experience with ion milling? I would appreciate a list
     of references, and some advice as to if this process is suitable for
     microwave integrated circuits. I've already consulted the Jan '85
     paper from Microwaves and RF.

     Thanks in advance,

     Avinash Kane
     Raytheon Systems Company
     Solid State Microwave
     Fullerton, California
     [email protected]