RDL Adhesion Strength Measurement, Phase 2

Statement of Work and Project Statement

Statement of Work (Version 1.0; March 12, 2025)
Project Statement (Version 1.0; March 12, 2025)

Background & Previous Work

Good RDL (redistributed layer) adhesion strength is critical over the lifetime of packaging — poor adhesion can lead reliability issues. RDLs are exposed to the manufacturing environment, which can lead to degraded adhesion between the RDL and other materials, such as encapsulant, insulation, die, carrier wafer, substrate, panel, etc. Furthermore, as RDL line spacing shrinks, it becomes more challenging to characterize adhesion strength.

Phase 1 of the RDL Adhesion Strength Measurement Project evaluated adhesion strength measurement methodologies and characterized RDL mechanical performances. The project team measured adhesion in trace features with widths below 20um, applying peel and shear test methods at these small length scales. They also gained insights into the physical mechanical responses using finite element modelling.

Focus of Phase 2

Phase 2 will extend the application of the selected trace adhesion measurement methodologies used in Phase 1, applying the selected test methodologies to a wider range of materials, RDL dimensions, and stress conditions. The team will also characterize adhesion degradation by exposing samples to defined temperature and humidity conditions.

Measurement techniques, procedures and results will be recommended to SEMI global standard development so the industry can use standardized measurement methodologies to characterize RDL patterns. Data will be validated by establishing correlations between package reliability and RDL adhesion for the various material interfaces and surface treatments.