Stretching-induced interconnect delamination in stretchable electronic circuits

O van Der Sluis (1, 2) , y y Hsu (3, 4) , P H M Timmermans (1) , M Gonzalez (3) , J P M Hoefnagels (2)

1 Philips Applied Technologies
2 TU/e - Eindhoven University of Technology [Eindhoven]
3 IMEC INTPAC / REMO
4 KU Leuven - Catholic University of Leuven = Katholieke Universiteit Leuven

Stretchable electronics offer increased design freedom of electronic products. Typically, small rigid semiconductor islands are interconnected with thin metal conductor lines on top of, or encapsulated in, a highly compliant substrate, such as a rubber material. A key requirement is large stretchability, i.e. the ability to withstand large deformations during usage without any loss of functionality. Stretching induced delamination is one of the major failure modes that determines the amount of stretchability that can be achieved for a given interconnect design. During peel testing, performed to characterize the interface behaviour, the rubber is severely lifted at the delamination front while at the same time fibrillation of the rubber at the peel front is observed by ESEM analyses. The interface properties are established by combining the results of numerical simulations and peeling experiments at two distinct scales: the global force-displacement curves and local rubber lift geometries. The thus quantified parameters are used to predict the delamination behaviour of zigzag and horseshoe patterned interconnect structures. The accuracy of these finite element simulations is assessed by a comparison of the calculated evolution of the shape of the interconnect structures and the fibrillation areas during stretching with experimental results obtained by detailed in-situ analyses. Stretching induced interconnect delamination 2 (a) zigzag interconnect compliant substrate square pad (b) Figure 1. (a) Stretchable electronics: rigid islands with brittle components in a stretchable matrix interconnected with thin metal conductor lines (from www.stella-project.de) ; (b) patterned zigzag interconnection with square pads for the electrical connection

Mots clés: 6835; 4655; 4650

O van Der Sluis, y y Hsu, P H M Timmermans, M Gonzalez, J P M Hoefnagels. Stretching-induced interconnect delamination in stretchable electronic circuits. Journal of Physics D: Applied Physics, 2011, 44 (3), pp.34008. ⟨10.1088/0022-3727/44/3/034008⟩. ⟨hal-00588681⟩