Overlay accuracy on a flexible web with a roll printing process based on a roll-to-roll system

• Published in: Review of scientific instruments 2015-05, Vol.86 (5), p.055108-055108
• Main Authors: Chang, Jaehyuk, Lee, Sunggun, Lee, Ki Beom, Lee, Seungjun, Cho, Young Tae, Seo, Jungwoo, Lee, Sukwon, Jo, Gugrae, Lee, Ki-yong, Kong, Hyang-Shik, Kwon, Sin
• Format: Article
• Language: English
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.4921495

For high-quality flexible devices from printing processes based on Roll-to-Roll (R2R) systems, overlay alignment during the patterning of each functional layer poses a major challenge. The reason is because flexible substrates have a relatively low stiffness compared with rigid substrates, and they are easily deformed during web handling in the R2R system. To achieve a high overlay accuracy for a flexible substrate, it is important not only to develop web handling modules (such as web guiding, tension control, winding, and unwinding) and a precise printing tool but also to control the synchronization of each unit in the total system. A R2R web handling system and reverse offset printing process were developed in this work, and an overlay between the 1st and 2nd layers of ±5μm on a 500 mm-wide film was achieved at a σ level of 2.4 and 2.8 (x and y directions, respectively) in a continuous R2R printing process. This paper presents the components and mechanisms used in reverse offset printing based on a R2R system and the printing results including positioning accuracy and overlay alignment accuracy.