Sequential polymer lithography for chemical sensor arrays

A simple process for the deposition of up to six different polymers in selected areas to be used as sensitive layers in chemical sensor arrays is presented. The process is based on photolithographic processes and takes advantage of the balance between UV exposure dose, material tone and developers used. The sensing properties of the deposited films in the array were characterized by the in situ monitoring of volume expansion upon exposure to analytes using white light reflectance sspectroscopy. The swelling properties of processed films are compared to the unprocessed ones for the purpose of examining the variation induced by the processing steps (exposure and development circles). Additionally, the repeatability of the processes as well as the effect of analyte sequence is examined. This process offers good control of the lateral dimensions and the thickness of the polymeric films and allows for the parallel fabrication of sensors based on different transduction mechanisms including mass sensitive and stress induced bending chemical sensors.