Unpowered Opens Test with X-Ray Laminography

Last year’s ITC started a lecture series on unpowered opens testing. All papers last year recognized the importance of an effective method of detecting solder opens and all used some electrical method to detect solder opens, the most common manufacturing defect on today’s surface mount printed circuit boards. However non-electrical methods are available today with significant benefits such as high fault coverage of all pins, no need for bed-of-nails fixtures, capability to detect opens on almost all component types and also capability to detect marginal opens, the opens that pass an electrical test today, but are likely to fail in the near future. In figure 2, the K-pin did not make contact with the solder during the reflow process. Because of surface tension a very different shape of the solder is formed. The analysis of the mechanical characteristics of these two solder joints will clearly detect the solder open.