One of the most innovative and developed flexible transparent substrate materials in the last few years is flexible glass. This Tutorial course is intended for engineers, technicians, and others involved with vapor deposition of thin films by magnetron sputtering, and who is interested in a better understanding of challenges and opportunities of thin film processing on flexible glass.

With thicknesses below 200 μm glass is thin enough to be flexible and opens as a new substrate material a wide range of new application fields. For applications - e.g., displays, OLEDs, or sensors - flexible glass enables realization of thin, light, robust, curved, and conformable devices.

Besides the challenge of substrate handling, the functionalization of the surface by thin films using PVD deposition methods also has to be optimized for further processing of a device. The thermal and dimensional stability of the coated substrate influences device fabrication and processing in sheet-to-sheet and roll-to-roll.

Due to the low thickness of flexible glass, the handling generally presents challenges for manufacturers of thin-film coatings. Mechanical film stress is here one of the main influences of the bendability of flexible glass. The sputtering process parameters have to be adjusted for multiple processing procedures, to improve processing stability and manufacturing of high quality films. Experimental results will be used to illustrate the challenges during thin film processing on flexible glass. The influence of selected process parameter for high deposition rate sputtering on the film- and substrate-stress will be discussed. Several examples of functional layer stacks on flexible glass, such as transparent conductive coatings, anti-reflective coatings, and infrared-blocking coatings including their properties will be demonstrated. The properties of these functional layers and layer stacks will be compared with those on flexible polymer substrates.

Transparent conductive oxides (TCOs) are also key materials in optoelectronic applications; mainly indium tin oxide (ITO) and indium zinc-oxide (IZO) are the most popular materials. For highly conductive TCO films thermal pre and post- annealing process steps are standard in film processing. Recently, ultra-short time annealing methods like flash lamp annealing (FLA) in the millisecond time-range, are gaining more importance for improved performance of thin films and surfaces refinement and will be also discussed in this Tutorial. The ability of FLA enables new options for high quality TCO film fabrication, also on flexible glass.

The focus of the Tutorial is pointing out critical parameters of thin-film sputter deposition for an improved handling and performance of flexible glass, and will showing possible path ways forward for optimized thin film processing on flexible glass. The Tutorial course concludes with a detailed discussion of the challenges, chances and solutions of flexible glass processing.