Microklin

Microklin is a family of photo-curable, epoxy-based resins used in microfabrication to produce high-aspect-ratio microstructures on silicon, glass, and polymer substrates. Sold as negative-tone photoresists, Microklin resins form crosslinked networks upon ultraviolet exposure, enabling durable features for microfluidic channels, MEMS components, and optical microstructures.

Composition and processing: The standard formulation combines an epoxy oligomer, crosslinking monomers, and a photoinitiator system. After coating on a substrate by spin coating, a soft bake removes solvent. Exposure with near-UV light (typically 365–405 nm) defines the pattern, followed by a post-exposure bake to promote crosslinking. Development uses organic solvents such as PGMEA or cyclopentane-based cleaners, with a final hard bake to improve thermal stability.

Properties: Microklin resists exhibit high glass-transition temperatures, strong chemical resistance, minimal shrinkage, and good optical clarity, with typical thickness ranges of a few to several tens of micrometers.

Applications: widely used in microfluidics, soft-lithography masters for PDMS replication, MEMS structural layers, and micro-optical components.

History: The Microklin family was developed in the late 1990s by research groups seeking high-temperature, solvent-resistant resists for microfabrication. Since then, multiple manufacturers have offered compatible formulations, with variations in sensitivity and resolution.

Safety and handling: as with other epoxy-based photoresists, Microklin components can cause skin and eye irritation. Use appropriate PPE and proper ventilation; handle waste according to local regulations.