MEMS device with two-stage motion limit structure

A microelectromechanical systems (MEMS) device comprising:

• a substrate;
• a proof mass spaced apart from the substrate and capable of moving relative to the substrate, wherein the proof mass is configured to pivot about a first axis of rotation, and the proof mass includes a first section on one side of the first axis of rotation and a second section on an opposing side of the first axis of rotation, the first section being formed with greater mass than the second section;
• and
• a motion limit structure comprising an arm structure flexibly coupled to a first one of the proof mass and the substrate, the arm structure extending from the first one of the proof mass and the substrate proximate the first section of the proof mass, the arm structure is configured to pivot about a second axis of rotation that is parallel to the first axis of rotation, and the arm structure has a first contact region and a second contact region, wherein the first contact region and the first stop region are displaced away from the second axis of rotation by a first distance in a direction parallel to a surface of the substrate, the second contact region and the second stop region are displaced away from the second axis of rotation by a second distance in the direction parallel to the surface of the substrate, the second distance being less than the first distance, wherein:
• in response to a shock force imposed upon the proof mass that causes the proof mass to move, the first contact region is configured to contact a first stop region on a second one of the proof mass and the substrate;
• and
• following contact of the first contact region with the first stop region and upon a continuation of the shock force imposed upon the proof mass, the second contact region is configured to contact a second stop region on the second one of the proof mass and the substrate such that contact of the second contact region with the second stop region reduces a contact force between the first contact region and the first stop region.

A microelectromechanical systems (MEMS) device comprising:

• a substrate;
• a proof mass spaced apart from the substrate and capable of moving relative to the substrate, the proof mass is configured to pivot about a first axis of rotation, and the proof mass includes a first section on one side of the first axis of rotation and a second section on an opposing side of the first axis of rotation, the first section being formed with greater mass than the second section;
• and
• a motion limit structure comprising a cantilevered arm structure having a first end flexibly coupled to the proof mass at a pivot location, wherein the arm structure extends from the first section of the proof mass and is configured to pivot about a second axis of rotation that is parallel to the first axis of rotation, the second axis of rotation is displaced away from the first axis of rotation in a direction parallel to a surface of the substrate, and the arm structure has a first contact region and a second contact region, the second contact region being positioned closer to the pivot location than the first contact region, wherein the first contact region and the first stop region are displaced away from the second axis of rotation by a first distance in a direction parallel to a surface of the substrate, the second contact region and the second stop region are displaced away from the second axis of rotation by a second distance in the direction parallel to the surface of the substrate, the second distance being less than the first distance, and wherein:
• in response to a shock force imposed upon the proof mass that causes the proof mass to move, the first contact region is configured to contact a first stop region on a second one of the proof mass and the substrate;
• and
• following contact of the first contact region with the first stop region and upon a continuation of the shock force imposed upon the proof mass, the second contact region is configured to contact a second stop region on the second one of the proof mass and the substrate such that contact of the second contact region with the second stop region reduces a contact force between the first contact region and the first stop region.

A microelectromechanical systems (MEMS) device comprising:

• a substrate;
• a proof mass spaced apart from the substrate and capable of moving relative to the substrate, wherein the proof mass is configured to move in a first direction substantially parallel to a surface of the substrate;
• and
• a motion limit structure comprising a cantilevered arm structure having a first end flexibly coupled to a first one of the proof mass and the substrate at a pivot location, the arm structure extending from the first one of the proof mass and the substrate proximate a first edge of the proof mass, the arm structure is configured to pivot about an axis of rotation that is perpendicular to the surface of the substrate, and the arm structure has a first contact region and a second contact region, the second contact region being positioned closer to the pivot location than the first contact region, wherein:
• in response to a shock force imposed upon the proof mass that causes the proof mass to move, the first contact region is configured to contact a first stop region on a second one of the proof mass and the substrate;
• and
• following contact of the first contact region with the first stop region and upon a continuation of the shock force imposed upon the proof mass, the second contact region is configured to contact a second stop region on the second one of the proof mass and the substrate such that contact of the second contact region with the second stop region reduces a contact force between the first contact region and the first stop region.