A position measurement system for precision alignment of roll-to-roll printing and sensitivity analysis of thermal deformation

Roll-to-roll processing in the field of printed electronics is the process of creating electronic circuits or devices on a roll of flexible plastic or metal foil, and it can be used in the manufacture of many products, such as RFID tags, solar cells, and flexible display panels, at a much lower cost than that in the semiconductor lithography process. This process is also more efficient in producing electronic devices in a large volume than semiconductor lithography. As with lithography, roll-to-roll processing also needs to achieve accurate layer-to-layer alignment in fabricating multi-layered circuits or devices. This alignment precision, in fact, is a critical factor in determining the integration and performance of printed electronics. In other words, it is essential to achieve highly precise alignment in roll-to-roll printing for the full commercialization of printed electronics. To that end, this study proposes an alignment pattern that is directly printed on a web as a solution that can enhance the alignment precision in roll-to-roll printing. Based on this, the study also proposes a web position measurement system using optical measurement instruments and verifies its applicability and reliability. Considering the fact that tension on the web and heat generated in the process of curing may deform the web, we conducted experiments and simulations to analyze the measurement sensitivity when the web is actually deformed and we present the results of the study.