In a message dated 98-03-16 06:34:35 EST, you write: > I would like to know if we are any nearer to having IPC SIR combs designed > to go under BGA devices? > Do the IPC have any recommendations for dealing with the situation in the > absence of these coupons? I would say no. Considering that BGAs are an array of balls designed to contact the board surface, comb patterns under BGAs is not practical. Most SIR testing that I have done relative to BGAs has involved daisy chaining the pads together, such that alternating rows of balls form the cathode and anode of the SIR test pattern. There are various ways to approach designing such an SIR test pattern, depending on what you are looking for. My own preference is to take the two center rows of balls, daisy-chain them together, and do SIR on the two parallel lines. It should give worst case. As far as I know, the IPC does not have any efforts at this time to examine SIR under BGAs. Not to say we couldn't, but right now we are focusing on test environment levels (temperature and RH for various tests). Out of curiosity, is there many others out in TechNetLand that are interested in doing SIR under BGAs? Doug Pauls Chairman, SIR Task Group ################################################################ 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 web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################