Mems devices utilizing a thick metal layer of an interconnect metal film stack

A Microelectromechanical System (MEMS), comprising:

• a substrate;
• a released proof mass disposed over a first area of the substrate and having:
• a first body region comprising a thick metal layer over a thin metal layer, the thick metal layer having a film thickness that is at least five times greater than that of the thin metal layer;
• and
• a first sensing structure comprising the thin metal layer, but lacking the thick metal layer;
• a frame disposed over a second area of the substrate, the frame having:
• a second body region comprising at least one of the metal layers;
• and
• a second sensing structure comprising the thin metal layer, but also lacking the thick metal layer, and separated from the first sensing structure by a gap to register a change in capacitance with displacement of the proof mass relative to the frame.

A Microelectromechanical System (MEMS) gyroscope or accelerometer, comprising:

• a substrate including CMOS circuitry;
• a released proof mass electrically coupled to the CMOS circuitry and formed in thin film metal interconnect layers over the CMOS circuitry, and including a plurality of first coupling fingers cantilevered from the substrate, wherein the proof mass includes a first body region including a thick metal layer separated from a thin metal layer, the thick metal layer having a film thickness that is at least five times greater than that of the thin metal layer, and wherein the first coupling fingers comprise the thin metal layer, but lack the thick metal layer;
• and
• a frame surrounding at least two sides of the proof mass and electrically coupled to the CMOS circuitry and forming the thin film metal interconnect layers, wherein the frame includes a plurality of second coupling fingers interdigitated with the first coupling fingers to register a change in capacitance in response to deflection in one or more spring physically connecting the proof mass to the frame, the one or more spring
• comprising at least the thin metal layer, but lacking the thick metal layer.

A method of forming a Microelectromechanical System (MEMS), the method comprising:

• receiving a substrate;
• patterning body regions of a proof mass and surrounding frame in a metal film stack including a thick metal layer separated from a thin metal layer by dielectric, the thick metal layer having a film thickness that is at least five times greater than that of the thin metal layer;
• and
• patterning sensing structures of the proof mass and frame into a metal film stack including the thin metal layer, but lacking the thick metal layer;
• and releasing the proof mass from the substrate.