---------- Greetings and Salutations J. Fjelstad, What are typical thata JA and thata JC values for the Tessera microBGA (tm) packages? I'm mainly wondering if this design could be used for conduction cooled applications. Also, is this reduction it stress technique only limited to micro? What about 1 and 1.27 mm designs? We are not a big user of BGA but we can get backed into a corner with design trade-offs. Thank You, Kevin Thorson Loral Defense Systems - Eagan [log in to unmask] ---------- From: TechNet-request To: TechNet Subject: Re: Protection of BGA Solder Joints Date: Saturday, February 17, 1996 12:27AM Hello Roger, Hitachi is a licensee of the Tessera microBGA (tm) package and is developing their capability for volume manufacture at this time. One unique ability of the Tessera technology is to decouple the mismatch in coeffiecients of thermal exapansion between the silicon and the FR-4 by means of a patented compliant interposer. Recently completed finite element modelling performed by Tessera shows a near 20x reduction in stress in the solder ball joints using this technology. Should you desire more information please feel free to contact me and I will provide you with contacts in Japan working the project. Regards, J. Fjelstad