Normally closed in-channel micro check valve

A check valve assembly comprising:

• a channel having a width in a range of from about 10 μm to about 400 μm connected to a substrate, said channel including a front portion and a rear portion;
• and
• a check valve connected to the substrate between the front portion of the channel and the rear portion of the channel, said check valve having a width in a range of from about 50 μm to about 500 μm, and comprising
• a valve seat connected to the front portion of the channel;
• a collapsed chamber positioned on the substrate and adjacent to the valve seat;
• and
• a sealing cap connected to the collapsed chamber, said sealing cap including an edge portion adapted to contact a sealing area of the valve seat in a closed position, thereby sealing the check valve.

A method for fabricating a check valve, comprising:

• depositing a first polymer layer on a substrate;
• depositing a sacrificial layer having a shape corresponding to a chamber on the first polymer layer;
• depositing a second polymer layer on the sacrificial layer to form the chamber;
• forming a valve seat over the chamber, said valve seat having a perimeter including a contacting edge;
• forming a sealing cap on the chamber, said sealing cap having a perimeter including a sealing edge that overlaps the contacting edge of the valve seat;
• removing the sacrificial layer;
• and
• collapsing the chamber, thereby pulling the sealing edge into sealing contact with the contacting edge.