PNNL

Abstract

Stretchable wiring and stretchable bonding between rigid chip/component and stretchable substrate are two of the key factors for stretchable electronics. Here, a low cost and highly stretchable paste is developed with Ag micro flakes and PDMS, which can be used to fabricate stretchable wirings and bondings under a low curing temperature of 100 °C with printing method. Recoverabilities as recovery time and recovery resistance of the wirings and bondings are defined and discussed. The wiring with a low resistivity of 8.7 × 10-5 ·cm shows much better recoverability than nanowire based wirings due to the flake nature of the Ag particles. When stretched to 50% and 100% of strain, the resistance of the patterned wiring increases to only 1.1 and 2.1 times, respectively. Moreover, the resistance of the wiring during 20% tensile cyclic test remains within 1.1 times even after 1000 cycles, showing long time durability. On the other hand, the paste is also used as a bonding material to assemble a zero-Ohm chip on the stretchable substrate to fabricate a stretchable demo, whose resistance increased to only 1.9 times when stretched to 50% of strain. The developed pastes can be expected to make various stretchable wirings, bondings and packaging structures by simple printing process, enabling mass production of stretchable electronic devices.