Flexible device and component reliability study using simulations

Abstract

With the miniaturization of mobile electronic devices, the flexible electronics are being used more and more in the industry, such as the flexible printed circuit (FPC) and flexible displays [1]. With the products becoming flexible and bendable, the reliability could become a serious issue in some cases if not designed properly. Examples of such concerns are bending and impact reliability. Unfortunately, there is no any systematic method for analyzing the reliability of the flexible electronics that we want to follow at this stage. In this paper, the reliability of the FPC and the flexible displays are discussed. Specifically, ball drop simulation, and three-point bending and twisting simulation are used to analyze the reliability of the flexible displays; and simulations of bending FPC with different component layout patterns are computed in order to understand the mechanical behaviour of the FPC under the corresponding load conditions. Based on the comparison of maximum von Mises stresses, design suggestions are given. Moreover, based on the practical design of the flexible device, a simulation method for bending the device along wrist is presented to simulate the phenomena within the device during its practical use. At the same time, system level simulation model is built to simulate the assembly process. Finally, according to the simulation results, the device reliability is evaluated and design suggestions are provided.

Bending Setups for Reliability Investigation of Flexible Electronics

“…Even the connection to fast moving parts with very high lifetime cycles, for example, read heads of optical drives, is achieved using flexible film connections. The investigation of the dynamic bending reliability of the components is indispensable [ 97 ].…”

The Contact Characteristics and NMOS performance of ACF-Bonded ultra-thin chip-on-flex (UTCOF) interconnects for bendable electronics

“…The package module with bending curvature of 1.25 inch passed the functionality test [8]. For UTCOF package, a number of studies about bending capacity, peeling strength, failure mode, reliability and electrical performance of interconnect have been presented [9] [10]. However, the relationship between electrical performances of devices and interconnections when a real die used in the package after various processes are still lack investigation critically.…”