Preliminary Evaluation of DIP/Socket Connection Reliability

The availability and recent use of large-scale integration and field programmable memory dual in-line packages (DIP's) has resulted in increased use of DIP sockets and also increased need for reliability data on DIP/socket connections. This experimental study was implemented to explore the reliability of various DIP/socket combinations in terms of contact resistance performance after being subjected to various environmental tests. The parameters explored were 1) DIP lead material and finishes, 2) socket contact finishes and configurations, and 3) insertion levels of 1, 5, and 15 insertions of the DIP's into the sockets. Three different Dip/socket interfaces were studied: Au/Au, Au/solder, and solder/solder. These were distributed over 20 combinations of 5 DIP's and 4 sockets. Thermal aging, temperature cycling, temperature cycling with high humidity, an industrial atmosphere test, and a control group were the 5 environments used. Although the tests are not complete, the major preliminary conclusions are as follows. 1) High contact resistance at the DIP/socket interface is a significant failure mode for DIPs that are socketed. Proper choice of DIP lead and socket finishes and socket design can reduce the probability of this type failure. 2) The gold/gold contact is the best DIP/socket combination tested. 3) Thick gold plating is superior to thin gold plating. 4) The gold/solder contacts are generally unacceptable. 5) The solder/solder contact did not perform well in the study and its use is not recommended. 6) Increasing the number of insertions of the DIP into the socket generally cause increased contact resistance as environmental tests progress.