IPC International Community magazine an association member publication
Issue link: https://iconnect007.uberflip.com/i/1542698
JANUARY 2026 I I-CONNECT007 MAGAZINE 57 You mentioned another case where the sol- der joint strength seemed to have shifted for no apparent reason. Tell more about that. Yes, in another case example, we had a previously reliable board design where the designer's choice of component was common. Again, suddenly, we began seeing failures in the life cycle testing around fractured shoulder connections, something we had not encountered before, and it consistently showed up on all 32 connections to that specific component: a QFN type of component. What happened here? It turns out that using a component performing fine on a four layers of copper is not always a simple case of a carry- over, copy/paste type of approach to eight layers of copper . Eight layers of thick, heavy copper vs. just four layers with the same plastic body of the QFN component give you two very different CTEs. That is why, at just one quarter of the intended lifespan testing, all the joints were showing fractures. Simply using a SAC305 type of alloy with the QFN solder connections on a thick board was not suitable, so the fix here was the implementation of a niche process, an underfill process tailored for the QFN. This gave the extra robustness for the solder connections, that was necessary to survive the lifecycle testing. Tibi, what advice do you give designers and assemblers to be more mindful of this type of change, and hopefully, to circumvent them from ever happening in the first place? Just doing copy/paste in the context of using the same component with the same solder paste on next generation products may be dangerous and very costly without the proper testing prior to launch in manufacturing. The bottom line is that reliability is a holistic approach. Isolated improvements are not enough; a systematic approach is essential. DFR and risk mitigation must be proactive. DFX methodology (DFM, DFA, DFT, DFO) early in the design phase reduces risks, preventing costly failures later. Component and material selection, process development, and process control are critical for a reliable product and compliance with industry stan- dards ensures consistency. Thank you, Tibi. It is always a pleasure catching up with you and very educational. DESIGN007 Table 1: Applicable IPC specifications on cleanliness and contamination from the perspective of the presentation Area Key IPC Specs Purpose Board design IPC-222X Series Design requirements and considerations, including cleanliness Assembly cleanliness requirements ( CH 8) IPC-J-STD-001 Defines allowable contamination and process validation Ionic cleanliness overview IPC-WP-019 Clarifying the cleanliness chapter in J-STD-001 Visual cleanliness (assemblies) IPC-A-610 Acceptability of visible residues Bare board contamination IPC-601X Series (601) Defines PCB fabrication cleanliness limits Cleaning process guidance IPC-CH-65 How to clean, measure, and troubleshoot Cleanliness test methods IPC-TM-650 2.3.25 (ROSE), 2.3.28 (IC), 2.6.3.7 (SIR) How to measure ionic contamination and reliability