TY - GEN
T1 - An inverse procedure for estimating the Anand viscoplastic constitutive model parameters for copper free-air ball
AU - Paranjothy, Sai Sudharsanan
AU - Subbarayan, Ganesh
AU - Jung, Dae Young
AU - Sammakia, Bahgat G.
N1 - Publisher Copyright: © Copyright 2015 by ASME.
PY - 2015
Y1 - 2015
N2 - Due to its superior mechanical and electrical properties, as well as low cost, Cu is gradually replacing Au as wire bonding material. However, since copper is a stiffer material, it requires greater bonding force, which in turn increases risk of bond pad cratering and inter-layer dielectric (ILD) fracture. A critical challenge to numerically modeling the pad cratering or ILD fracture is the availability of appropriate constitutive models for the Cu free-air balls (FAB). In this work we first present rate and temperature dependent force-displacement response of micron-sized Cu FAB characterized using a custom-built highprecision microtester. From the experimental forcedisplacement data, Anand viscoplastic constitutive model parameters are obtained using an inverse finite element analysis procedure, where the material parameters are iterated through an automated procedure until the finite element and experimental force-displacement responses match. The constitutive model parameters to describe the FAB behavior at low and intermediate strain rates and at high temperatures are obtained and reported in this paper.
AB - Due to its superior mechanical and electrical properties, as well as low cost, Cu is gradually replacing Au as wire bonding material. However, since copper is a stiffer material, it requires greater bonding force, which in turn increases risk of bond pad cratering and inter-layer dielectric (ILD) fracture. A critical challenge to numerically modeling the pad cratering or ILD fracture is the availability of appropriate constitutive models for the Cu free-air balls (FAB). In this work we first present rate and temperature dependent force-displacement response of micron-sized Cu FAB characterized using a custom-built highprecision microtester. From the experimental forcedisplacement data, Anand viscoplastic constitutive model parameters are obtained using an inverse finite element analysis procedure, where the material parameters are iterated through an automated procedure until the finite element and experimental force-displacement responses match. The constitutive model parameters to describe the FAB behavior at low and intermediate strain rates and at high temperatures are obtained and reported in this paper.
UR - https://www.scopus.com/pages/publications/84953911271
U2 - 10.1115/IPACK2015-48653
DO - 10.1115/IPACK2015-48653
M3 - Conference contribution
T3 - ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2015, collocated with the ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels
BT - Advanced Electronics and Photonics, Packaging Materials and Processing; Advanced Electronics and Photonics
PB - American Society of Mechanical Engineers
T2 - ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems, InterPACK 2015, collocated with the ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels
Y2 - 6 July 2015 through 9 July 2015
ER -