Development of a multi-layer SU-8 process for terahertz frequency waveguide blocks

This paper presents the development of a multilayer SU-8 process for use in fabricating terahertz frequency waveguide blocks. This process consists of anisotropic silicon etching to form an octagonal horn antenna, lithographic definition of SU-8 layers, and planarization of those layers through lapping. A 1.6 THz waveguide block is fabricated using this process and compared with blocks formed using computerized numerically controlled (CNC) milling and laser-hardened polymer techniques. The SU-8 process demonstrates better accuracy with the advantage of batch processing when compared with these other techniques.