Optimization of Microstructure Patterning for Flexible Bioelectronics Application

Recent advancements in flexible electronics and wearable sensors have given biomedical technology a new edge overcoming the limitations of traditional rigid silicon-based electronics. Furthermore, high flexibility of these wearable sensors enables it to conformally sit over any uneven surface helping in accurate determination of any physical, chemical, or physiological parameter associate with the surface. Conventionally expensive micro/nano photolithography techniques under strict clean room conditions are used for the development of these flexible and wearable biomedical sensors with high degree of accuracy and sensitivity. However, the developed wearable sensors need not only be extremely sensitive, but also cost effective for its successful usage. To address this, the present work discusses the use of a photo-patternable UV sheet for realization of micro patterns over flexible copper cladded surface eliminating the need of costly clean room facilities. It demonstrates the standardization of various design geometries using the photo-patternable UV sheet over the flexible surface similar to photolithography process and involves optimization of the exposure timing of the UV sheets and their development time towards various design patterns over different thick film metal surfaces. Finally, patterned micro devices like micro-electrodes were successfully realized using the above process to ascertain its efficacy.