James- As a relatively new user and designer of PBGA, here's an off the top of my head list of issues: 1. Eutectic solder joint reliability, especially under conditions of high-shock and extreme temperature dormant storage for military applications: How can we better model and analyze the solder array? How can we create accurate predictions of fatigue life, using a better understanding of the evolution of alloy microstructure, as it affects joint lifetime (see Darrell Frear, of Sandia Labs, papers over the last 10 years). When is underfilling required for extreme environment applications for PBGAs? 2. For thin, 2-layer PBGA substrates, a better understanding of compromised solder joint reliability, where balls are located on the opposite side of the substrate, near the edge of the die. At what point will thicker, stiffer substrates, and "compliant" die atttach joints or materials, be able to mitigate this problem? 3. Improved moisture resistance (JEDEC level 2 or 1) for PBGA: what improvements in PBGA organic substrates, die attach materials, and die encapsulant/overmolding are required? 4. For Au wire bonded PBGAs: a better understanding of "gold embrittlement" issues, when eutectic solder balls are attached to Au over Ni substrate platings. How does the intermetallic layer evolve and grow with time and exposure to elevated temperatures? What Au plating thicknesses, or percent Au in solder joint levels, will lead to solder joint reliability problems? 5. PBGA solder ball coplanarity control, for more producable assemblies using PBGA components. What complanarities are required as a function of pre-attachment ball height? 6. PBGA will probably dominate over ceramic. The use of PWB-based substrates and eutectic PbSn will continue to make PBGA the more attractive and lower cost option. -Michael Alderete > ---------- You wrote... > ------------------------------ > > Date: Wed, 16 Sep 1998 08:30:40 -0500 > From: "Michaud, James (STP)" <[log in to unmask]> > Subject: Re: X-ray for open joints on BGA's ? > > Marcelo - > > Hello. I am a Reliability Engineer working for a Medical > Electronics > company. We're currently reviewing BGA reliability. We'll be producing > equipment for hospital Emergency Rooms. > > I've noticed the discussion on BGAs you've been involved in. > I'm concerned about BGA reliability issues. You mentioned > "there is > a lot that the industry still do not know about reliability." In your > opinion, > what are the most critical BGA reliability issues? Our guys > think > plastics are better than ceramics. What do you think? > > James Michaud > Guidant-CRM/CPI > Dept. 5512, MS F240 > 4100 Hamline Ave. N. > St. Paul, MN 55112-5798 > (612) 582-7842 > > > > > ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################