Event
CALCE Webinar - Temperature-Humidity-Bias and Temperature Cycling Reliability of Printed Electronics
Thursday, April 17, 2025
11:00 a.m.-12:00 p.m.
https://web.calce.umd.edu/seminars/cws20250417.htm
Electronic assemblies are being realized in novel non-planar (curvilinear and 3D) form factors, thanks to additive manufacturing (3D printing) methods. Aerosol jet printing (AJP) is emerging as one of the leading additive manufacturing methods for printed hybrid electronics (PHEs). This new combination of materials, processes, and architectures requires a new understanding of the associated reliability physics to obtain full advantage of this technology and realize its industrial potential. This presentation focuses specifically on the reliability of AJP PHE circuits under temperature-humidity-bias (THB) conditions and temperature cycling (TC) conditions. The conductive ink used in these studies is sintered nanoparticle-based silver (AgNP).
PHE coupons for electrochemical migration (ECM) under temperature-humidity-bias conditions are fabricated by depositing AgNP interdigitated comb-pattern traces (motivated by IPC 9201) and polymeric dielectric layers with the AJP process onto FR4-Cu substrates. ECM is important because it leads to various failure modes due to conductive dendritic growth, such as dielectric breakdown, leakage currents, and short circuits. A set of baseline ECM durability tests are also conducted using geometrically identical specimens that are fabricated with conventional Cu conductors. The end outcome is an empirical acceleration model for ECM degradation of additively printed silver traces, and a comparison to the THB degradation rate of conventional (subtractive) Cu traces.
PHE coupons for the TC study are fabricated by depositing AgNP conductor traces and polymeric dielectric layers with the AJP process onto copper-based printed wiring board (PWB) substrates. PWB substrates are made of two materials (Glass-FR4 composite and Ceramic), to generate different levels of thermomechanical strains in the silver conductors. Specimens are cycled at -40oC/125oC, and the number of temperature cycles-to-failure (CTF) is measured from the test. Weibull characteristic life and variability are estimated for each substrate type. Failure analysis is conducted to identify the failure sites and failure modes. Finite element analysis (FEA) is used to quantify the resulting local thermo-mechanical deformation history at the critical failure region. The end outcomes are life and acceleration models for TC degradation of printed silver traces, which relate the estimated strain history at the failure site to the CTF.
In conclusion, this study assesses the temperature-humidity-bias reliability and temperature cycling reliability of Aerosol-Jet printed conductive AgNP traces, to push the envelope further in realizing printed hybrid electronics for realistic application conditions.
About the Presenters:
Abhijit Dasgupta is Jeong H. Kim Professor of Mechanical Engineering at the University of Maryland (UMD), with research experience in the microscale and nanoscale mechanics and reliability physics of engineered materials used in conventionally and additively manufactured heterogeneous flexible electronic systems and intelligent microsystems. He holds a Ph.D. in Theoretical and Applied Mechanics from the University of Illinois at Urbana-Champaign (UIUC) and has been a principal investigator at the Center for Advanced Life Cycle Engineering (CALCE) at UMD for over 30 years, conducting research in reliability physics, design for reliability, accelerated stress testing, and real-time health management. He has published over 300 articles and conference papers; served on editorial boards of three international archival journals; presented over 50 workshops and short courses; helped form research and educational roadmaps for the electronics industry, and provided consulting services to numerous industry leaders. He has presented numerous keynote talks at international conferences, received 6 best-paper awards, and received 8 major awards in recognition of his research and educational contributions. He is an ASME Fellow, past Chair of the ASME Electronic and Photonic Packaging Division (EPPD), past member of the ASME Design, Manufacturing, and Materials Segment Leadership Team (DMM-SLT), and Current Chair of the Reliability Technology Working Group in the Heterogeneous Integration Roadmap (HIR) Team sponsored by IEEE/ASME/SEMI/IEPS/EDS.
