Xenon Flash Lamp Lift-Off Technology without Laser for Flexible Electronics

Abstract

This study experimentally investigated process mechanisms and characteristics of newly developed xenon flash lamp lift-off (XF-LO) technology, a novel thin film lift-off method using a light to heat conversion layer (LTHC) and a xenon flash lamp (XFL). XF-LO technology was used to lift-off polyimide (PI) films of 8.68–19.6 μm thickness. When XFL energy irradiated to the LTHC was 2.61 J/cm2, the PI film was completely released from the carrier substrate. However, as the energy intensity of the XFL increased, it became increasingly difficult to completely release the PI film from the carrier substrate. Using thermal gravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR) and transmittance analysis, the process mechanism of XF-LO technology was investigated. Thermal durability of the PI film was found to deteriorate with increasing XFL energy intensity, resulting in structural deformation and increased roughness of the PI film surface. The optimum energy intensity of 2.61 J/cm2 or less was found to be effective for performing XF-LO technology. This study provides an attractive method for manufacturing flexible electronic boards outside the framework of existing laser lift-off (LLO) technology.

Photonic Lift-off Process to Fabricate Ultrathin Flexible Solar Cells

“…Overall, these results demonstrate that the PLO process can aid in fabricating lightweight, ultrathin (<20 μm) solar cells that could be attractive for space and stratospheric applications. Further, this process, as demonstrated, also enables monolithic device fabrication on the top of polymeric films, not requiring transferring the completed devices to foreign substrates after lift-off, which is a typical step in other lift-off mechanisms. − …”

“…The temperature at the LAL–PI interface greatly exceeds this during the PLO process, resulting in the release of the PI film and device layer. In this way, PLO is fundamentally similar to the laser lift-off process − but with the advantage of large-area illumination…”

“…Lift-off methods using localized heating with a laser have become attractive . However, beam-width limitations pose a challenge to process throughput . Another problem is that excimer lasers operating with ultraviolet (UV) wavelength lead to ashing of organic and polymer materials due to their strong light absorption .…”

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

“…The cured PI films on the LTHC carrier glass were placed on the stage and then triggered by XFL pulses. The applied XFL Energy was fixed at a pulse height of 500 V, and the exposure time was varied from 1–7 ms [ 17 ]. The thicknesses of released films were 12 μm.…”

“…Bian et al [ 10 ] reported that lowering the excimer laser fluence and increasing the number of scans reduces the thickness of polyimide film during the LLO process. Lee et al [ 17 ] reported a new lift-off process using a Xe Flash lamp power source and a specially developed light-to-heat conversion (LTHC) layer. At this time, no studies have reported the investigations of differently structured polymer substrates in the new lift-off process.…”