In this study, an ink-jet printed poly(methylmethacrylate)(PMMA) solution with mixed organic solvent to form insulator was presented. A detail observation of ring edge behavior for Ink-Jet Printing (IJP) device and its process parameters relation had been evaluated. One of the layer structure consisted of a thin layer of adhesive polymer (polyvinyl acetate: PVA) between bottom electrode and printed insulator layer, and then to treat the spincoated thin PVA with CF4-plasma to raise the contact angle up to 40∼50 degrees. Besides, a mixed solvent comprised of one solvent having lower boiling point and another one having higher boiling point was used to improve the ring-effect as well. Heating the platform as the droplet is landing also mitigates the effect of coffee-ring. Single-layer insulator device is very easy to be leakage, so triple-layered insulator device is made and then has better capacitance characteristic. Experimental results indicated that the leakage current for ink-jet fabricated multi-layered insulator was about 10nA/cm2 at 3V, and the dielectric constant for the printed insulator was about 3.0.
Chia-Hsun Chen, Yuh-Zheng Lee, Chung-Wei Wang, Ming-Huan Yang, Kevin Cheng, Jane Chang, Chung-Ping Liu, Sha-Man Wang, "Ink-Jet Printed Passive Electronic Components: Metal-Insulator-Metal Device" in Proc. IS&T Digital Fabrication Conf., 2005, pp 76 - 78, https://doi.org/10.2352/ISSN.2169-4451.2005.21.2.art00025_3