Fabrication and design rules of three dimensional pyrolytic carbon suspended microstructures

Fabrication of suspended pyrolytic carbon 3D-microstructures from SU-8 was studied in variable pyrolysis temperatures. The dimensions of suspended parts were from 3 µm to 1500 µm in length with one to four anchor points. The pyrolysis temperatures were 800 °C to 1100 °C, and the resulting pyrolysed carbon structures were analyzed in terms of shrinkage, surface roughness, electrical resistivity and carbon bond type. The structural stability of the suspended structures is strongly dependent on the number of anchor points. The successful parameter range, structure design rules and the common failure mechanisms are discussed. The temperature dependency on material properties is studied and analyzed. We observed changes in three stages of the pyrolysis process that impact on the final structural shape and stability.