TY - GEN
T1 - Modeling adhesive failure in electronic packages
AU - Chew, H. B.
AU - Guo, T. F.
AU - Cheng, L.
PY - 2006
Y1 - 2006
N2 - The numerous pores and cavities present in adhesive underfills increase the susceptibility of microelectronic packages to Type II cracking. In this work, we focus on the effects of softening-rehardening and pressure-sensitivity on adhesive failure. An axisymmetric unit-cell study is first performed to ascertain the failure mechanisms in a softening-rehardening polymer. Results show that shear banding is the dominant failure mechanism under low stress triaxiality, while internal necking is the likely failure mode for highly constrained pressure-sensitive adhesives. With this in mind, a population of discrete voids is introduced ahead of a crack in an adhesive sandwiched between elastic substrates. We show that strain softening tends to lower the stress-carrying capacity of the adhesive, while strain rehardening suppresses both the intensity and spatial extent of damage. An increase in the rate of rehardening also reduces the oblacity of the voids. For adhesives with high pressure-sensitivity, rapid voiding occurs throughout the adhesive at low loads, leading to formation of extended damage zones.
AB - The numerous pores and cavities present in adhesive underfills increase the susceptibility of microelectronic packages to Type II cracking. In this work, we focus on the effects of softening-rehardening and pressure-sensitivity on adhesive failure. An axisymmetric unit-cell study is first performed to ascertain the failure mechanisms in a softening-rehardening polymer. Results show that shear banding is the dominant failure mechanism under low stress triaxiality, while internal necking is the likely failure mode for highly constrained pressure-sensitive adhesives. With this in mind, a population of discrete voids is introduced ahead of a crack in an adhesive sandwiched between elastic substrates. We show that strain softening tends to lower the stress-carrying capacity of the adhesive, while strain rehardening suppresses both the intensity and spatial extent of damage. An increase in the rate of rehardening also reduces the oblacity of the voids. For adhesives with high pressure-sensitivity, rapid voiding occurs throughout the adhesive at low loads, leading to formation of extended damage zones.
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U2 - 10.1109/EPTC.2006.342812
DO - 10.1109/EPTC.2006.342812
M3 - Conference contribution
AN - SCOPUS:50249118331
SN - 142440665X
SN - 9781424406654
T3 - Proceedings of the Electronic Packaging Technology Conference, EPTC
SP - 787
EP - 792
BT - 2006 8th Electronics Packaging Technology Conference, EPTC
T2 - 2006 8th Electronics Packaging Technology Conference, EPTC
Y2 - 6 December 2006 through 8 December 2006
ER -