Large area cleaning and activation of flexible ultra-thin glass by nonthermal atmospheric-pressure plasma

Abstract

Flexible ultra-thin glass is used as a substrate or packaging material in microelectronics engineering, where the level of cleanliness determines the quality of the final product. Surface properties of glass are governed by a surface nano-layer. Besides cleaning from coarse impurities, the demand is also for nano-decontamination, where standard cleaning proves insufficient. In microelectronics and printed flexible electronics, the bonding of thin structures deposited using printed conductive inks on glass substrates is of essential importance. The non-thermal, atmospheric-pressure plasma generated by diffuse coplanar surface barrier discharge (DCSBD) was studied as an effective pre-treatment method for cleaning and activation of glass surfaces, implementable into large-scale in-line manufacturing. Two industrial adaptations of DCSBD system were applied on two types of ultra-thin flexible glass to compare the effects of plasma treatment of glass in both relaxed, and bent state. DCSBD "Air-pillow"with a planar discharge unit is designed for contactless treatment of smooth flat largearea surfaces. A roll reactor with a concavely curved DCSBD unit is intended to exemplify its integration into roll-to-roll manufacturing. The effect of plasma treatment and its stability was analyzed with water contact angle measurement and X-ray photoelectron spectroscopy. Significant wettability improvement was achieved with both applied DCSBD geometries, with better effect uniformity and durability after using the DCSBD in the planar configuration.