Micro-Fabrication of All Silicon 3 Meter GC Columns Using Gold Eutectic Fusion Bonding

Abstract

This work highlights a new bonding technique for micro-fabrication of an all silicon 3 meter gas chromatography column that could withstand the temperature cycling required for axial temperature programming. Proper separation of a complex gas mixture using a miniaturized GC column is critical in improving the overall performance of a lab on a chip system for environmental monitoring, medical diagnoses, and gas impurity measurement. To improve upon current methodology the column was first fabricated using micro-fabrication processes; experimentally validated using a high performance 3 meter GC column coated with OV-1 stationary phase. This process demonstrates that the bonding quality of the GC column to a 200 μm thick silicon lid was improved when using a new gold eutectic bonding technique. Furthermore, a new quality control technique was developed in order to test the overall bonding quality of the bonded pieces by fixing the bottom column and applying a mechanical shear force to the top lid. This method could ultimately be used for quality control of each individual bonded columns. The gold bonded interface of the gold diffusion bonded area is further characterized using surface analysis. In the end, the utility of the column was demonstrated by separating 21 organic compounds with different Kovats retention index and molecular weights in less than five minutes.