Strain Guidance for PCBAs
Wednesday, December 7, 2022

Section: Board Assembly

Project Leaders

Project Leader: Jagadeesh Radhakrishnan (Intel) Co-Project Leaders: Matt Kelly (IBM)

Statement of Work & Project Statement


The IPC9704 standard was revised February 2012 (now IPC9704A) to encompass the impact of Pb-free electronics and to incorporate consistent strain gage placement/measurement techniques to monitor printed circuit board assembly (PCBA) flexure within a manufacturing environment. With the intent of making IPC9704A strictly a methodology document, appendices A and B that were present in original IPC9704 documentation were removed. These appendices are very important. They outline strain limits and provide reference for rate limited strain guidance for eutectic solder. New Pb-free content additions within these appendices are intended to form the basis of a new white paper guidance document. The legacy SnPb guidance will be maintained in the white paper. The benefit of this new approach is to ensure that new Pb-free strain limiting guidance can be more easily updated in a timely manner, as new information becomes available. This project team is being formed to develop such a white paper.

Scope of Work

  • Will encompass various Pb-free technologies and materials – SnAgCu based alloys, laminates, PCB thickness
  • Intended to provide manufacturing strain guidance for Pb-free BGA only (by package attributes – BGA pitch, package body side and package type along with pad design) based on existing data collection
  • Planned to make recommendation for further testing, if necessary, based on existing data collection
  • Recommendations will be provided to the IPC/JEDEC committee for further industry review and feedback/comments.
  • Develop BGA strain guidance will apply to primary attach and rework manufacturing process operations

This project did not do a final report.