Investigation of the Chemical Structure of Ultra-Thin Polyimide Substrate for the Xenon Flash Lamp Lift-off Technology.

Seong Hyun Jang,Young Joon Han,Kwan Hyun Cho,Geonho Lee,Jae Woong Jung,Sang Yoon Lee,Jun Choi

doi:10.3390/polym13040546

Seong Hyun Jang, Young Joon Han + Show 5 more

Open Access

https://doi.org/10.3390/polym13040546

Copy DOI

Abstract

Lift-off is one of the last steps in the production of next-generation flexible electronics. It is important that this step is completed quickly to prevent damage to ultrathin manufactured electronics. This study investigated the chemical structure of polyimide most suitable for the Xe Flash lamp–Lift-Off process, a next-generation lift-off technology that will replace the current dominant laser lift-off process. Based on the characteristics of the peeled-off polyimide films, the Xe Flash lamp based lift-off mechanism was identified as photothermal decomposition. This occurs by thermal conduction via light-to-heat conversion. The synthesized polyimide films treated with the Xe Flash lamp–Lift-Off process exhibited various thermal, optical, dielectric, and surface characteristics depending on their chemical structures. The polyimide molecules with high concentrations of –CF3 functional groups and kinked chemical structures demonstrated the most promising peeling properties, optical transparencies, and dielectric constants. In particular, an ultra-thin polyimide substrate (6 μm) was successfully fabricated and showed potential for use in next-generation flexible electronics.

Highlights

Flexible electronics, such as foldable, rollable, and wearable devices, are receiving attention for their ability to maintain the performance of existing flat electronics while transforming to suit the environment of the user [1,2]
The PI substrates used in the experiment were designated as non-fluorine polyimide (BPI series) or fluorine polyimide (FPI series), and synthesized in a manner suitable to their chemical structures
The synthesized PAA samples were spin-coated onto a specially fabricated carrier glass with a Mo-light-to-heat conversion (LTHC) layer, and the PI films were produced through a thermal curing process

Summary

Introduction

Flexible electronics, such as foldable, rollable, and wearable devices, are receiving attention for their ability to maintain the performance of existing flat electronics while transforming to suit the environment of the user [1,2]. One of the most important technologies used in flexible electronics is substrate formation including lift-off process. It has been determined that PI, which has extremely high heat and chemical resistance, practical mechanical properties, and advantageous insulating properties, is suitable as a substrate component of high-technology electronic devices. Because of these characteristics, transparent PI films, which reduce the charge transfer complexes (CTCs) between intra- and inter-chain systems, have the potential to act as electrical multilayer components in flexible displays and solar cells [8,9]. The whole device, including the flexible PI substrate, is detached from the carrier substrate.

Methods

Results

Conclusion