Multi-cell piston motion membrane microelectromechanical systems (mems) apparatus and process

A method comprising:

• forming a fixed electrode structure on a device substrate;
• forming a patterned piston motion membrane array over the fixed electrode structure;
• forming an array of anchor structures that connect to a passivation layer over the fixed electrode structure;
• forming a patterned transduction membrane array that connects to the array of anchor structures and an array of posts that connects the patterned transduction membrane array to the patterned piston motion membrane array;
• release etching, via a plurality of etch release structures in the patterned transduction membrane array, the patterned piston motion membrane array, the array of anchor structures, and the array of posts to create a cavity for the patterned piston motion membrane array to translate freely along the array of anchor structures;
• and
• sealing the plurality of etch release structures in the patterned transduction membrane array to establish a predetermined pressure in the cavity.