Roll-to-roll sputter deposition on flexible glass substrates

Abstract

Flexible glass is very thin glass below 100μm, and flexible enough to be wound in a roll. Flexible glass is a very attractive substrate when we consider the roll-to-roll production of flexible displays, because it has thermal stability up to the temperature range for the display fabrication, excellent barrier properties, a very smooth surface and high transparency. However, the roll-to-roll deposition on the flexible glass is still not easy because of the fragility of the glass and the number of the reports is limited.In this paper, we demonstrated successful roll-to-roll depositions of ITO on flexible glass 50μm and 100μm thick, 300mm wide and up to 50m long, using a compact sputter roll-coater with some modifications for the flexible glass handling. A 190nm ITO coating deposited on the 50μm thick flexible glass showed the sheet resistance to be as low as 7.5Ω/sq when heating the substrate to about 250°C. We also demonstrated continuous roll-to-roll deposition of 24nm ITO on 100μm thick and 50m long flexible glass substrate. The properties of this coating were revealed to have 102Ω/sq sheet resistance and 90% light transmission. Through these experiments, we demonstrated the feasibility to use flexible glass as the substrate for the roll-to-roll vacuum deposition process.