Reliability Assessment of Encapsulated Flexible Hybrid Electronic Assemblies Under Board-Level Drop Test

Flexible-hybrid electronics (FHE) are gaining increasing traction in consumer electronics. This surge in the popularity of FHE can be attributed to the capacity to conform to diverse shapes in addition to weight reduction and a slim profile. The FHEs need to be encapsulated using encapsulants to mitigate the effects of shock loads. Most of the prior research on FHE is focused on the printing process development and process performance. The reliability of the FHEs under drop and vibration is not well understood. This paper focuses on the assessment of the survivability of direct-write additive printed electronics, the evaluation of the reliability of encapsulants in promoting drop-survivability, and the analysis of the failure modes in encapsulated additively printed FHE. In this paper, FHE circuits are printed using a direct write platform and encapsulated to improve reliability, followed by board-level drop testing. The boards are tested at a G-level of 40G, typical of automotive applications. The number of shock events to failure has been assessed for the FHEs, and the reliability of the various encapsulant materials has been investigated. The failed samples have been analyzed to understand the specific failure modes. The study could have practical implications for manufacturers developing FHEs for consumer and harsh environmental applications, and it provides valuable insights into the survivability and failure modes of encapsulated FHEs.