ASME’s Journal of Electronic Packaging Features Article from iNEMI Project

• By: iNEMI
• On: 09/05/2024 17:05:53
• In: iNEMI Blog

Information from iNEMI's Moisture Induced Expansion Metrology for Packaging Polymetric Materials Project is highlighted in ASME's Journal of Electronic Packaging. The article, “Experimental Method to Measure High-Temperature Hygroscopic Swelling in Laminate Core, Epoxy Mold Compounds and Dielectric Build-Up Films,” discusses use of a technique developed by the iNEMI team to analyze high-temperature hygroscopic swelling characterization of different epoxy mold compounds (EMCs) and dielectric build-up films (DBFs). The new metrology recommended by the team extends swelling strain measurement capabilities beyond current temperature limits of existing commercial measurement techniques. 

Electronic packaging is made up of polymeric materials that absorb moisture from the environment during substrate fabrication, packaging assembly and test processing. This moisture can cause material hygroscopic swelling and induce hygro-stress, which can lead to component warpage, delamination or popcorn failure during reflow or reliability tests.  

This iNEMI project was organized with the goal of enabling the materials sector to better understand quantifiable material properties at higher temperatures and moisture concentrations. Knowledge of the moisture properties of polymeric materials is critical for optimizing package material and design to minimize moisture-related failures. However, hygro-swelling properties are not widely available due to a lack of measurement methods and a temperature limitation of 20-120°C with existing commercial measurement techniques.

The Moisture Induced Expansion Metrology for Packaging Polymetric Materials Project developed an experiment-based assessment of metrology options for characterization of materials expansion measurement and has recommended a new metrology for moisture-induced CTE that extends capabilities beyond current temperature limits to enable measurement at higher temperatures. The ultimate goal is to give materials companies a better understanding of quantifiable material properties at higher temperatures and moisture concentrations to enable them to develop innovative new materials that minimize the risk of failure due to moisture and humidity.

The team's approach maintains specimens in a saturated state using a high-pressure enclosure, while digital image correlation (DIC) is used to measure in situ strain change in the specimen due to hygrothermal expansion. Hygroscopic swelling strain is obtained by removing the thermal strain component. This enables swelling characterization measurements above the temperature and humidity capability of typical commercial instruments. 

The results showed that moisture-induced swelling is significant compared with thermal expansion and increases substantially with temperature above the glass transition temperature (Tg). EMCs were found to absorb more moisture and swell more compared to DBFs with comparable properties. The coefficient of hygroscopic swelling (CHS) for DBFs and EMCs was quite similarly low at low temperatures, but for EMCs, the CHS increased more at high temperatures. Results are compared against analytical solutions, other measurement methods, and published data.

Authors & Publication Dates

The article is now available online (published August 24) and will be included in the March 2025 edition of the print publication. The authors are:     

• Ian Chin (Intel), project leader 
• Wei Keat Loh (Intel)
• Seow Chien Kee (Intel)
• Yi He (Intel)
• Zulkifly Abdullah (Universiti Sains Malaysia)
• Masahiro Tsuriya (iNEM), project manager

If you have any questions or need additional information about this or other iNEMI packaging projects, please contact Masahiro Tsuriya (m.tsuriya@inemi.org).