Three-way microvalve device and method of fabrication

A method of fabricating a three-way pressure-balanced micro-valve device, the method comprising:

• providing a bottom substrate,
• micromachining the bottom substrate so as to form in the bottom substrate a bottom fluid chamber having a depth extending partially into the bottom substrate,
• forming, in the bottom substrate, at least one fluid port that passes completely through the bottom substrate, so as to fluidically connect to the bottom fluid chamber,
• providing a top substrate,
• micromachining the top substrate so as to form in the top substrate a top fluid chamber having a depth extending partially into the top substrate,
• forming, in the top substrate, at least one fluid port that passes completely through the top substrate, so as to fluidically connect to the top fluid chamber,
• micromachining the top substrate to include a valve seat or sealing ring around one of the at least one fluid port in the top substrate,
• providing a middle substrate, and
• micromachining the middle substrate so as to be a membrane layer with one or more openings to allow fluid to flow from the top fluid chamber to the bottom fluid chamber, or to allow fluid to flow from the bottom fluid chamber to the top fluid chamber, wherein the membrane layer is located near or at the center of a fluid chamber including the top fluid chamber and the bottom fluid chamber, and wherein the bottom substrate or the top substrate includes a plurality of ports.