Direct-Write and Aerosol Jet Processes with Evaluation for Additively Printed Electronics

Abstract

Printed electronics, with their eco-friendliness, cost-effectiveness, and scalability, are becoming popular as a replacement for traditional silicon electronics. Flexible batteries, wearable sensors, and screens are just a few of its applications. With ongoing research to improve its performance and surface morphologies, the technology is appropriate for the developing wearable industrial sector due to its durability and malleability. The advantages of printable electronics over conventional production methods include fewer steps in the process, less resource consumption, and a smaller environmental effect. Printable circuits can be used with flexible substrates like plastic films. In this study, the major focus is on the development of flexible hybrid electronics using additive printing techniques. The study includes the process development for additively printed traces initially with various ink materials. Additive printed electronics lack standard test protocols which have also been addressed through this study. The process development of printed traces is later tested for its flex reliability in order to address the failure mode and reliability analysis of the printed traces. The analysis of printed trace reliability could help us understand its real-world lifespan. Due to a lack of standards, the performance of the additively printed traces is benchmarked with the subtractive flexible samples performance which are accepted under industrial standards. The initial study of conductor materials such as silver and copper gives a strong baseline to attach active and passive components using additively printed bonding materials to build Flexible Hybrid Electronics (FHE). The developed recipes were implemented in two application circuits, namely, LC filter and amplified inverting circuit. To understand the reliability of the attached components using various bonding materials a folding test has been conducted to evaluate the number of cycles to failure. The cycles to failure data quantification would help us in evaluating the bonding materials for various applications. The study includes the process development requirements for multilayer development as it becomes critical to partially cure the samples until the last stage. The study addresses the need for encapsulation of the developed FHE for a better life and improves the reliability of the developed circuits. Overall, this study covers a range of topics related to developing FHE using additive printing techniques, including developing processes for additively printing traces, and bonding materials, evaluating the flex reliability of printed traces, analyzing various materials, and developing standard test protocols. By doing so, the researchers aim to improve our understanding of these techniques and materials to develop fully functional FHE products.