Measurement of Defects in Spin Coated Polyimide Films

Polyimide is a material often used in thin film neural microelectrodes. In this work, we processed thin films from three different polyimide precursors, Pyralin PI2611, Durimide 7510 and U-Varnish S, and tested them with respect to their defect density. We regard defects as areas of any size where the insulation of the thin film is damaged. All three materials were measured with a defect density less than 0.2 cm^-2. To obtain a defect free polyimide layer it is crucial to process the precursor in a particle free environment.