Originally developed and patented by IBM in 1989 and commercially introduced by MicroChem Corporation in 1996, SU-8 rapidly found wide use in UV and X-ray lithography as a negative tone photoresist for microsystem technology applications [1]. Its very low optical absorption in UV and X-ray ranges leads to uniform exposure conditions for thicknesses up to a few millimetres resulting in high structural quality and excellent sidewall verticality. Cured SU-8 is highly resistant to solvents, acids and bases and has excellent thermal stability, making it attractive for applications in which the SU-8 is considered as a permanent part of the device. For instance, it is used in fabrication of X-ray lenses [2], metamaterials [3], single-mode and multi-mode optical waveguides [4], [5], and micro channels for bio applications [6].