Electrical Trees Grown from Micron-Scale Artificial Channels Fabricated by 2PP 3D Printing

This paper reports on early-stage exploration into a new method for fabrication of micron-scale voids in polymers for electrical tree testing. A state-of-the-art 3D print technique, two-photon polymerization (2PP) lithography, was employed to print artificial channels of 4 μm in diameter. The channel was printed into a traffic-cone-shaped structure including a needle shaped void for a traditional needle electrode to sit in. The needle was glued to the cone and then cast into epoxy resin cube to form a needle-plane geometry with 2 mm insulation distance. Electrical trees grew from the artificial channel at low voltages, while a higher voltage was required to drive the tree structure to extend beyond the printed traffic cone into epoxy resin. This fabrication technique will allow experiments to determine the sensitivity of tree formation to micron scale voids in polymers.