Laser direct writing of thick hybrid polymer microstructures

This work presents patterning of thick (10-50 μm) hybrid polymer structures in ORMOCER (Organically Modified Ceramics) by rapid laser direct writing (LDW). ORMOCERs combine polymer-like fabrication processes with glass-like surface chemistry that is beneficial for biochips. In our study, different process parameters of laser-writer were studied, in order to find the optimal dose for each of the laser beam spot sizes and for different ORMOCOMP^® layer thickness. LDW enables superior control over structure geometry and different shapes i.e. pillars, ridges and triangles were written in a single step on silicon substrate. Round pillars of height ~ 49 μm (spinned at 2000 rpm) were obtained using optimized process parameters of laser writer. The ORMOCOMP^® triangles of ~ 10 μm height corresponding to spin coating at 10000 rpm with 30°, 45° and 90° angles were obtained. The sharpness of corners in these triangles (a few micrometers) indicates that LDW of ORMOCOMP^® microstructures has advantages over proximity lithography and is useful for applications requiring high definition and edge roughness. Microfluidic directional wetting (fluidic diode) replicated in ORMOCOMP^® by LDW was also tested. The objective of this work is to design and to fabricate micrometer range chips patterned by LDW for microfluidic applications.