Digital Image Correlation Idea Phase Project Status Update Member Meeting Luxembourg Project Lead: Thilo Sack (CLS) Project Facilitator: Laurence Schultz (HDPug) May 25, 2016

Digital Image Correlation There are strong interests in understanding the reliability behavior of the stacked microvias, especially the effect of the structure designs such as the number of stacks, the pitch between the vias, and the stacking microvia on/off a buried via, etc.

Digital Image Correlation The main reliability challenges have been the microvia separation, interfacial delamination and the copper fatigue failure. Experimental evidence suggests that HDI structures experience different stresses and failure modes during thermal operation, and the challenges become tougher under the Pb-free assembly.

Project Descriptive Paragraph The Digital Image/Speckle Correlation (DISC) Project is an experimental physics-based study, which will mainly rely on a unique but mature DISC method for the measurement of the thermal stress in microvias and surrounding areas. The quantitative measurement of the strain and other deformation kinematic parameters make it possible for a mechanistic-based failure analysis. © HDP User Group International, Inc.

Digital Image Correlation

Digital Image Correlation © HDP User Group International, Inc.

Digital Image Correlation © HDP User Group International, Inc.

© HDP User Group International, Inc. Phase 1 Proposal Phase 1 of the project will make use of micro-via laminate PWBs which were at opposite ends of the reliability spectrum to see how it correlates to the ATC data from the Multi-Lam project. Three specific samples will be included in the Phase 1 evaluation: Hi CTE, 18 layer, 3 stack “off buried” Lo CTE, 12 layer, via stack “on buried” Hi CTE, 18 layer, via stack “on buried” © HDP User Group International, Inc.

© HDP User Group International, Inc. Phase 1 Proposal Leftover samples of as fabricated multi-lam project PWBs will be prepared for digital speckle correlation testing and then the test method applied to see if it can predict the reversal of some of the failure mechanisms. If so, this would advance the State of the Art both from a reliability prediction method but also from an evaluation of design trade-offs perspective. © HDP User Group International, Inc.

© HDP User Group International, Inc. Progress Several conference calls have taken place to define scope of project Samples identified for use by Bill Birch / Ivan Strasnicky Next Steps Send samples to Prof. Lu at Ryerson for sample prep and feasibility study © HDP User Group International, Inc.

Interested Members Celestica Curtiss-Wright PWB Interconnect Panasonic Hitachi Ryerson University (non-member)