IC-processed polymer nano-liquid chromatography system on-a-chip and method of making it

A method of fabricating a high pressure nano-liquid chromatography system on-a-chip, the method comprising:

• providing a substrate having a front first side and having a back second side;
• wherein the substrate has a layer disposed on the front first side;
• etching in two places the substrate from the back second side to form two holes and two diaphragm regions in the substrate adjacent to the holes;
• wherein the two diaphragm regions have the layer disposed on the front first side disposed on two diaphragms;
• from the front first side, etching the layer disposed on the front first side above the two diaphragm regions in the substrate to remove the layer over the diaphragms;
• patterning a sacrificial material on the front first side of a substrate to define a column region which covers the diaphragm regions,
• forming an encapsulant over the front first side of the substrate and the sacrificial material;
• wherein forming the encapsulant comprises depositing Parylene, and prior to deposition of Parylene, a moat is etched into the substrate adjacent to the channel to receive and anchor the deposited Parylene;
• etching through the diaphragm regions from the back second side to open an inlet hole and an outlet hole;
• removing the sacrificial material defining a column region through the inlet hole and the outlet hole to form the column region,
• wherein the method further comprises forming a epoxy passivating layer over the encapsulant,
• wherein the system provides a pressure limit of 1000 psi or greater.