TY - JOUR
T1 - Flip Chip Bonding on Stretchable Printed Substrates; The Effects of Stretchable Material and Chip Encapsulation
AU - Malik, Muhammad Hassan
AU - Kaczynski, Jaroslaw
AU - Zangl, Hubert
AU - Roshanghias, Ali
PY - 2023/1/24
Y1 - 2023/1/24
N2 - Stretchable printed electronics have recently opened up new opportunities and applications, including soft robotics, electronic skins, human-machine interfaces, and healthcare monitoring. Stretchable Hybrid systems (SHS) leverage the benefits of low-cost fabrication of printed electronics with high-performance silicon technologies. However, direct integration of silicon-based devices on conventional stretchable substrates such as thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS) is extremely challenging due to their temperature instability. In this study, a recently developed thermoset, stretchable substrate (BeyolexTM) with superior thermal and mechanical properties was employed to realize HSS via direct flip chip bonding. Here, ultra-thin chips (UTC) with a fine-pitch, daisy-chain structure were flip-chip bonded by using anisotropic conductive adhesives, while the complementary circuitry was facilitated via screen-printed, stretchable silver tracks. The bonded samples successfully passed the reliability assessments after being subjected to cyclic 30% stretch tests for 200 cycles. The potential benefits of chip encapsulation after integration with the stretchable substrate to withstand larger strains were demonstrated by both mechanical simulation and experimental results.
AB - Stretchable printed electronics have recently opened up new opportunities and applications, including soft robotics, electronic skins, human-machine interfaces, and healthcare monitoring. Stretchable Hybrid systems (SHS) leverage the benefits of low-cost fabrication of printed electronics with high-performance silicon technologies. However, direct integration of silicon-based devices on conventional stretchable substrates such as thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS) is extremely challenging due to their temperature instability. In this study, a recently developed thermoset, stretchable substrate (BeyolexTM) with superior thermal and mechanical properties was employed to realize HSS via direct flip chip bonding. Here, ultra-thin chips (UTC) with a fine-pitch, daisy-chain structure were flip-chip bonded by using anisotropic conductive adhesives, while the complementary circuitry was facilitated via screen-printed, stretchable silver tracks. The bonded samples successfully passed the reliability assessments after being subjected to cyclic 30% stretch tests for 200 cycles. The potential benefits of chip encapsulation after integration with the stretchable substrate to withstand larger strains were demonstrated by both mechanical simulation and experimental results.
KW - Stretchable hybrid systems (SHS), ultra-thin chips (UTC), hybrid integration, printed electronics, anisotropic conductive paste (ACP), stretchable, Beyolex
M3 - Article
VL - 8
JO - Flexible and Printed Electronics
JF - Flexible and Printed Electronics
IS - 1
ER -