Fabrication of Metallic Microchannel Mold using X-ray LIGA for Microfluidic Applications

Metallic microchannel mold for microfliudic applications is demonstrated based on X-ray LIGA technology. High aspect ratio microchannel made of SU-8 photoresist was constructed on a stainless substrate to create a mold template using X-ray lithography generated by synchrotron light source. Following X-ray lithography, the SU-8 mold template was filled with electroplated nickel to produce the required mold insert structure. To achieve a good bonding between the electroplated nickel and the stainless steel substrate, the electroplated surface was activated with sulfuric and Wood's strike before nickel was electrodeposited. The over-electroplated structure was lapped and polished to obtain the final thickness. SU-8 mold template was finally removed and cleaned by plasma, resulting in the metallic microchannel mold for microchannel replication. A 10:1 mixture of pre-polymer PDMS was cast on to the metallic mold and peeled off to create the replicated PDMS microchannel. Replicated microchannel was attached on a glass substrate and injected with liquid to investigate the leakage problem. The proposed method can deliver the rapid replicated microchannel which is not complicated and simply applied for microfluidic applications.