Issue link: https://iconnect007.uberflip.com/i/1515637
40 DESIGN007 MAGAZINE I FEBRUARY 2024 results in the formation of voids, primarily on the cathodic side of the solder joint. Conclusions As the nickel-free finishes exhibit simi- lar high-frequency signal loss properties, it becomes important to evaluate other charac- teristics of these finishes. In this article, high- speed ball shear, drop shock performance and solder joint electromigration tests have been thoroughly undertaken for standard ENEPIG, thinner EN ENEPIG's, standard and modi- fied EPIG (no EN) as well as immersion silver, OSP, and a new silver-gold surface finish. All surface finishes were compared across the performance requirement matrix and a quality function deployment (Figure 5) was constructed to produce a data-driven tool to align surface finish performance against design needs. As it shows, there is no one perfect sur- face finish that fits every application. Fabrica- tors would pick the performance criteria with corresponding importance rating and evaluate the surface finishes according to their specific needs. DESIGN007 References 1. "Reassessing Surface Finish Performance for Next Generation Technology, Part 1," by F. Xu, M. Bunce, J. Coonrod, Design007 Magazine, June 2023. 2. "Reassessing Surface Finish Performance for Next Generation Technology," by F. Xu, M. Bunce, E. Long, and J. Watkowski, IPC APEX Expo, Jan 2023. 3. "The Effects of PCB Fabrication on High Fre- quency Electrical Performance," by John Coonrod, IPC APEX EXPO, 2015. 4. "Failure mechanisms of solder interconnects under current stressing in advanced electronic packages," by Y.C. Chan and D. Yang, Progress in Materials Science, 55 (2010) 428-475. 5. "Electromigration and Thermomigration in Pb- Free Flip-Chip Solder Joints," by C. Chen, H.M. Tong, K.N. Tu, Annual Review of Materials Research, 40 (2010) 531-555. Frank Xu, Ph.D, is surface finish technology man- ager at MacDermid Alpha Electronics Solutions. Martin Bunce is product director for MacDermid Alpha Electronics Solutions. John Coonrod is technical marketing manager for Rogers Corporation. Figure 5: Quality function deployment (QFD) matrix of various surface finishes.