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Multiple Lamination

Idea/Definition Information
Summary: 

The extended process time at high temperatures in multiple lamination designs coupled with multiple assembly cycles and rework cycles may cause stress that are undocumented. This project will attempt to provide statistically accurate data on multiple heat cycle stresses.

If you are interested in this project and would like to subscribe to the project mailing list, please click here (members only) or email the project facilitator, Jack Fisher - fish5er@hdpug.org.
 

Background: 

Many industry professionals are worried about the impact of ROHS on long term PWB reliability. With peak temperature differentials of approximately 30 degrees C, laminate parameters like CTE, Tg, and Modulus of elasticity are of major concerns. The stress on vias due to differential expansion and PTH failure modes like foil cracks, post separation, barrel cracks and corner cracks are all worrisome.

Problem: 

The extended process time at high temperatures in multiple lamination designs coupled with multiple assembly cycles and rework cycles may cause stress that are undocumented. This project will attempt to provide statistically accurate data on multiple heat cycle stresses.

Approach: 

A controlled experiment testing multiple lead free laminate survivality with a non-lead free control.

            Potential specifications are:

                        3 - lamination cycles

• 6X@288ºC – cross-sections

• 6X@260ºC Reflow – cross-sections

• IST

• Other testing? TBD

 

–Evaluate at 1mm and 0.8mm pitch

• Buried Via Array

• Through Via Array

• Stacked Microvias (2) on Buried Via Array

 

Initial Proposal San Jose 0211