Die stacking with controlled tilt and angular alignment

A micro-electromechanical system (MEMS) device comprising:

• a first MEMS component comprising a mass suspended above a first substrate and coupling the cover to the first substrate;
• a cover coupled to the first substrate disposed above the mass of the first MEMS component;
• an alignment recess formed at a top surface of the cover, wherein the alignment recess has a first length and a first width at a center of the alignment recess;
• and wherein the alignment recess has a second length that is less than the first length and a second width that is less than the first width at each of four corner regions of the alignment recess;
• a second substrate disposed on the top surface of the cover above the alignment recess, the second substrate having a third length that is greater than the second length and having a third width that is greater than the second length;
• and
• wherein the second substrate is bonded to the cover within the recess by die attachment material disposed within the alignment recess such that corners of the second substrate rest on a surface of the cover surrounding the alignment recess and the second substrate is bonded to the cover by the die attachment material within the alignment recess.

A method comprising:

• disposing a cover above a first micro-electromechanical system (MEMS) component comprising a mass suspended above a first substrate and coupling the cover to the first substrate;
• forming an alignment region on the top surface of the cover, the alignment region comprising:
• landing surfaces at four corners of the alignment region that extend to a first height above the top surface of the cover within the alignment region;
• a first raised notch partially surrounding a first landing surface at a first corner of the alignment region and extending above the first landing surface;
• and
• a second raised notch partially surrounding a second landing surface at a second corner of the alignment region that is diagonally opposite the first corner and extending above the second landing surface;
• and
• disposing a second substrate within the alignment region such that corners of the second substrate rest on corresponding landing areas in the alignment region with a first corner of the second substrate resting within the first raised notch and a second corner of the second substrate resting within the second raised notch;
• wherein positions of the first raised notch and the second raised notch define a first axis parallel to the top surface of the cover and positions of the first corner and the second corner of the second substrate define a second axis parallel to the top surface of the cover;
• wherein the first axis and the second axis are angularly aligned to within less than two degrees of rotation;
• and
• wherein elevations of the landing areas define a first plane and the second substrate is disposed within a second plane that is parallel to the first plane to within less than two degrees of tilt.

A first micro-electromechanical system (MEMS) device comprising:

• a cover disposed above a first MEMS component comprising a mass suspended above a first substrate and coupling the cover to the first substrate;
• an alignment region formed on the top surface of the cover, the alignment region comprising:
• landing surfaces at four corners of the alignment region that extend to a first height above the top surface of the cover within the alignment region;
• a first raised notch partially surrounding a first landing surface at a first corner of the alignment region and extending above the first landing surface;
• and
• a second notched feature partially surrounding a second landing surface at a second corner of the alignment region that is diagonally opposite the first corner and extending above the second landing surface;
• and
• a second substrate disposing within the alignment region such that corners of the second substrate rest on corresponding landing areas in the alignment region, wherein a first corner of the second substrate rests with the first raised notch and a second corner of the second substrate rests within the second raised notch;
• wherein positions of the first notch and the second notch define a first axis parallel to the top surface of the cover and positions of the first corner and the second corner of the second substrate define a second axis parallel to the top surface of the cover;
• wherein the first axis and the second axis are angularly aligned to within less than two degrees of rotation;
• and
• wherein the elevations of the landing areas define a first plane and the second substrate is disposed within a second plane that is parallel to the first plane to within less than two degrees of tilt.