Jim, Regarding the use of a test die in the BGA. It depends on what you are looking for in your test program. For BGA devices the presence of silicon does affect the joint reliability. The low Cte of the silicon seems to concentrate strain at the solder joints directly below the edge of the die. The joints that fatigue fail first tend to be the corner joints and the joints below the edges of the die. If all you are looking for in your testing is assembly solder joint reliability under temperature cycling conditions then a full test die is not needed. All the BGA needs is non active silicon and daisy chain connections to allow you to monitor joint integrity. Daisy chained dummy BGA components with no functional silicon are available off the shelf from Topline Components as well as vendors of BGA's for assembly process development. A full test die is useful if you are interested in getting power dissipation data for the BGA, or the board and system design, They can also be used to get stress, and humidity reliablility data for the BGA design. Apparently calibrating on silicon strain gauges and and humidity sensors is difficult, though I have not done this myself. Use of on silicon heaters and temperature measurement works very satisfactorily. The heaters can be used for power cycling and the junction temperature can be measured in the finished design. This is useful for checking the results of thermal models. Whether you need to use test die depends on what sort of business you are in. Using a full test die will add cost and time for procurement and packaging. If all you are interested in is solder joint life, then I don't think they are worth the extra. Jeremy Drake Design to Distrbution Ltd. Stoke on Trent, England. Original Message>> ================ This is a re-submittal. Apparently 1st one didn't make it out. I have heard of special test die (ie. silicon) developed to support reliability testing of surface mount solder joints; especially LCCs and BGAs. These die typically did continuity but also included other features such as * power cycling capability * strain gage measurement of stresses on die * ability to measure (on die) temperature and/or humidity/moisture content We are beginning to layout a test vehicle for BGA efforts and want to include a die in the vehicle (based on the literature that the die significantly effects the strains in the part during temp cycling and thus it's "life) and were considering using some special die (assuming that they were available). We assume we would have to pay to have these die "mounted" and wire bonded into the BGA vehicles we plan on testing. My questions are: a) Does anyone have any experience with using these "special test die" in life testing for SMD joints? If so, in hindsight was the "extra expense" worthwhile or not?? b) Does anyone know of any sources for the die? P/Ns? Capabilities (e.g. continuity, powercycling, etc). Thanks for your time. =============================== Jim Maguire Senior Principal Engineer Boeing Defense & Space Group PO Box 3999 M/S 3W-97 Seattle, WA 98124-2499 Phone (206)657-9063 Fax 657-8903 Email: [log in to unmask] ================================ =============================== Jim Maguire Senior Principal Engineer Boeing Defense & Space Group PO Box 3999 M/S 3W-97 Seattle, WA 98124-2499 Phone (206)657-9063 Fax 657-8903 Email: [log in to unmask] ================================ *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: TechNet- [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************