Precision overlay registration of micron sized features on unsupported flexible films

Roll-to-roll (R2R) flexible electronics manufacturing techniques may eventually provide a solution for continuous production of high quality flexible electronics devices at a significant cost reduction. The goal of the Center of Advanced Microelectronic Manufacturing (CAMM) is to establish and demonstrate tooling, materials and processes for roll-to-roll (R2R) flexible electronics manufacturing capability [1]. In this work, the roll-to-roll (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 process. 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 LC100 photoresist was used in this work. Soda lime glass substrates (Telic) were also used to establish the tool and process fundamental limits.