Lithographic patterning of conductive polyaniline

Electrically conducting patterns of polyaniline are made by utilizing conve ntional semiconductor industry process. First polyaniline is spin- or spray -coated on an insulating substrate and has a conductivity of 1-100 S/cm. Af ter that UV resist is spread on top of polyaniline, exposed by UV light, de veloped and removed. As a result one has a patterned polyaniline layer in i nsulating and in conducting form on top of the substrate. The conductivity remains essentially unaffected below the resist throughout the process and polyaniline turns insulating at places where the resist is removed. The dif ference between the electrically conducting part and the electrically insul ating part is upto 10(10). When the linewidth is smaller than 100 mu m the square resistance increases slightly, because the deprotonating liquid pene trates somewhat below the resist. Linewidths down to 10 mu m have been demo nstrated. The process has been utilized in making all-polymer circuit board s having resistors and capacitors made of polyaniline.