The photomask controls which portions of the thick SU-8 layer receive ultraviolet light. Those illuminated regions are then post-exposure baked, which crosslinks the epoxy photoresist and makes them resistant to development. Uncrosslinked regions are removed, leaving the intended relief geometry. This sequence transfers the mask design into a physical mold for later replication.
Post-exposure baking is the step that strengthens the illuminated SU-8 by promoting crosslinking within the epoxy photoresist. Development can then remove the uncrosslinked material while retaining the exposed pattern. Because the bake follows photomask exposure, it connects the optical patterning step to formation of a stable relief structure that can define microscale device features.
Liquid PDMS is cast against the completed relief structure, so it occupies the channels, chambers, and other patterned spaces. Curing solidifies the material while preserving the geometry imposed by the mold. After replication, the PDMS part can serve as a microfluidic platform whose architecture reflects the original patterned master.
Fabrication relies on a substrate, thick SU-8 epoxy photoresist, a photomask, ultraviolet exposure, and a post-exposure bake. A development step removes uncrosslinked resist, while liquid PDMS is used afterward for casting and curing. Together, these components convert a two-dimensional mask design into a three-dimensional microfluidic structure.
Researchers use these molds when biological experiments require reproducible microscale channels, chambers, or related structures. The replicated PDMS devices support cell culture, tissue engineering, and diagnostics, while also enabling studies of cellular behavior under controlled conditions. The mold therefore provides a fabrication foundation for experiments where device geometry helps establish a consistent biological environment.
Successful casting and curing preserve the master’s microscale architecture in PDMS, producing a device with reproducible channels, chambers, or related features. That physical consistency helps establish controlled conditions across biological studies. Researchers can consequently examine cellular behavior or build tissue-engineering and diagnostic platforms around a defined device layout.