RDL Adhesion Strength Measurement
Section: Packaging

Project Leaders

Project Leader: Lisa Chen, Intel

Project Co-Leader: Yanchun Deng, AT&S

Project Co-Leader: Frank Wang, Unimicron

Statement of Work and Project Statement ‚Äč


RDL (redistributed layer) adhesion for advanced substrates, fan-out wafer level packaging (FO-WLP) and panel level packaging (PLP) is critical for packaging lifetime quality. Poor adhesion strength can lead to circuit patterning quality and package reliability issues. RDL is exposed to the manufacturing process environment, which may cause degradation in the adhesion to other materials, such as the encapsulant, insulation, die, carrier wafer, substrate, panel, etc. 

Currently, there is no global standard to measure narrow (20µm and below) RDL adhesion strength. The only available measurement standard is an IPC standard that is for wider Cu trace adhesion to printed circuit boards. It is critical for the industry to have a means to identify potential quality risks due to insufficient adhesion strength.

Purpose of Project

The objective of the RDL Adhesion Strength Measurement project is to evaluate adhesion strength measurement methodologies and characterize RDL mechanical performances. The project will also establish potential common requirements for key material properties so that packaging companies and users have identical qualification requirements.

The project will take the following approach:

  • Evaluate the applicable adhesion strength measurement methodologies, validate selected methodologies and develop experimental guidelines.
  • Apply the defined methodology to characterize RDL adhesion for several material sets and conditions. This may include accelerated stress testing of the test coupon or test vehicle to assess the relationship between adhesion and package reliability.
  • Apply the validated methodologies and guidelines to characterize the RDL for FO-WLP and PLP. 


Adhesion Testing of Fine Line Patterns in Integrated Packages,” Frank Wang, Unimicron Technology Corp., iNEMI Session at IMPACT 2023, October 25, 2023; Taipei, Taiwan (available to members only)

RDL Adhesion Study for Advanced Packages,” presented by Steven Martell (Nordson), Wafer-Level Packaging Symposium, Session 2: Advanced Manufacturing and Test / Test Metrology for Advanced Manufacturing (February 14, 2023: Fremont, California) (Available to members only; requires log-in).  This presentation is based on information from iNEMI’s RDL Adhesion Strength Measurement Project.

Presentation from the call-for-participation webinar (March 2 & 3, 2021)



Masahiro Tsuriya