A Roll-to-Roll Photolithography Process for Establishing Accurate Multilayer Registration on Large Area Flexible Films

Roll-to-roll (R2R) flexible electronics manufacturing techniques may eventually provide a solution for continuous production of high quality flexible display devices at a significant cost reduction. The new display applications that can be enabled by using R2R technologies include inexpensive display, large area display, and etc. In this work, the R2R photolithography system and dependent materials and processes are used to establish baseline data for fabrication, registration and overlay of micron sized patterns on unsupported plastic in pieces and carried by a web. Enabling the use of unsupported plastic film is the first step in understanding the R2R overlay registration process for fabrication of high quality flexible displays. Test verniers with up to 0.1 micron measurement precision were used to read the overlay offsets. Micro-sized features with one micron overlay accuracy have been achieved on photoresist coated free standing 5 mil thick Dupont Melinex^® ST507 polyethylene terephthalate (PET) substrate. Rohm & Haas LC-100 photoresist was used in this work. Soda lime glass substrates (Telic) were also used to establish the tool and process fundamental limits.