Stacked-die MEMS resonator
A low-profile packaging structure for a microelectromechanical-system (MEMS) resonator system includes an electrical lead having internal and external electrical contact surfaces at respective first and second heights within a cross-sectional profile of the packaging structure and a die-mounting surface at an intermediate height between the first and second heights. A resonator-control chip is mounted to the die-mounting surface of the electrical lead such that at least a portion of the resonator-control chip is disposed between the first and second heights and wire-bonded to the internal electrical contact surface of the electrical lead. A MEMS resonator chip is mounted to the resonator-control chip in a stacked die configuration and the MEMS resonator chip, resonator-control chip and internal electrical contact and die-mounting surfaces of the electrical lead are enclosed within a package enclosure that exposes the external electrical contact surface of the electrical lead at an external surface of the packaging structure.
1. A multi-die package comprising:
a control die having a first surface;
electrically conductive structures extending perpendicularly from the first surface of the control die to a first exterior surface of the multi-die package to enforce a structural offset of the control die from the first exterior surface;
a microelectromechanical system (MEMS) die mounted to the control die;
at least one electrical connection between the MEMS die and the control circuit die to provide for electrical communication therebetween; and
encapsulation material disposed between and in contact with the electrically conductive structures and encapsulating the MEMS die;
wherein the control die further comprises circuitry to sense a temperature of the MEMS die and to generate correction information to adjust an electrical output of the MEMS die in dependence on sensed temperature;
wherein the first surface and the MEMS die are mounted in a manner coupled by a thermally-conductive material, so as to place the circuitry to sense the temperature and a MEMS structure with a movable element in thermal communication with one another.
2. The multi-die package of claim 1 wherein the control die comprises a complementary metal oxide semiconductor (CMOS) die.
3. The multi-die package of claim 1 wherein the electrically conductive structures are part of a common lead frame.
4. The multi-die package of claim 1 wherein the electrically conductive structures form at least part of a lateral surface of the multi-die package, the lateral surface being perpendicular to the first surface of the control die and perpendicular to the first exterior surface.
5. The multi-die package of claim 1 wherein the thermally-conductive material comprises an epoxy having silver particles.
6. The multi-die package of claim 1 wherein the at least one electrical connection comprises bondwires that electrically couple the MEMS die to the control die.
7. The multi-die package of claim 1 wherein the at least one electrical connection comprises solder bumps that electrically couple the MEMS die to the control die.
8. The multi-die package of claim 1 wherein the MEMS die comprises a resonant MEMS structure and the control die comprises circuitry to output a time-varying drive signal to the MEMS die to effect resonant motion of the resonant MEMS structure.
9. The multi-die package of claim 1 wherein the MEMS die comprises a resonant MEMS structure and said circuitry is to compensate for a frequency output of the MEMS resonant structure according to temperature sensed by said circuitry.
10. The multi-die package of claim 1 wherein the encapsulation material is disposed within a three-dimensional region of the multi-die package between the electrically conductive structures and between the first surface of the control die and the first exterior surface of the multi-die package.
11. The multi-die package of claim 1 wherein the MEMS die is flip-chip mounted to the first surface of the control die via electrically conductive elements.
12. A method of fabricating a multi-die package having a microelectromechanical system (MEMS) die and a control die having a first surface, wherein the control die comprises circuitry to sense a temperature of the MEMS die and to generate correction information to adjust an electrical output of the MEMS die in dependence on sensed temperature, the method comprising:
providing electrically conductive structures that extend perpendicularly from the first surface of the control die to a first exterior surface of the multi-die package to enforce a structural offset of the control die from the first exterior surface;
mounting the M EMS die to the control die using a thermally-conductive material, so as to place the circuitry to sense the temperature and a MEMS structure with a movable element in thermal communication with one another and in a manner such that the MEMS die and the control die are electrically-connected to one another to provide for electrical communication therebetween; and
disposing encapsulation material between and in contact with the electrically conductive structures in a manner so as to encapsulate the MEMS die.
13. The method of claim 12 wherein the control die comprises a complementary metal oxide semiconductor (CMOS) die, and wherein forming the electrically conductive structures that extend from the first surface of the control die comprises electrically coupling the electrically conductive structures with constituent electrical contacts of the CMOS die.
14. The method of claim 12 wherein the electrically conductive structures are part of a common lead frame and wherein providing the electrically conductive pillars comprises mounting the control die to the lead frame.
15. The method of claim 12 wherein forming the electrically conductive structures that extend from the first surface of the control die comprises exposing the electrically conductive structures at a lateral surface of the multi-die package, the lateral surface being perpendicular to the first surface of the control die and perpendicular to the first exterior surface.
16. The method of claim 12 wherein the thermally-conductive material comprises an epoxy having silver particles, and wherein mounting the MEMS die to the control die comprises using the epoxy to adhere the MEMS die to the control die.
17. The method of claim 12 wherein mounting the MEMS die to the controls die in a manner comprises using bondwires to electrically-couple the MEMS die to the control die.
18. The method of claim 12 wherein mounting the MEMS die to the controls die in a manner comprises using solder bumps to electrically-couple the MEMS die to the control die.
19. The method of claim 12 wherein mounting the MEMS die to the control die comprises mounting a MEMS die having a resonant MEMS structure to a control die that, when powered, outputs a time-varying drive signal to the MEMS die to effect resonant motion of the resonant MEMS structure.
20. The method of claim 12 wherein mounting the MEMS die to the control die comprises mounting a MEMS die having a resonant MEMS structure to the control die, wherein said circuitry is to compensate a frequency output in dependence on motion of the MEMS resonant structure as a function of temperature sensed by said circuitry.
21. The method of claim 12 wherein disposing encapsulation material between and in contact with the electrically conductive structures to encapsulate the MEMS die comprises disposing encapsulation material within a three-dimensional region of the multi-die package between the electrically conductive structures and between the first surface of the control die and the first exterior surface of the multi-die package.
22. The method of claim 12 wherein disposing encapsulation material between and in contact with the electrically conductive structures to encapsulate the MEMS die comprises disposing plastic encapsulant between and in contact with the electrically conductive structures and in a manner that encapsulates the MEMS die.
23. The method of claim 12 wherein mounting the MEMS die to the control die comprises mounting a die having a resonant MEMS structure to a die having circuitry to output a time-varying drive signal to the MEMS die to effect resonant motion of the resonant MEMS structure.
24. The method of claim 12 wherein mounting the MEMS die to the control die comprises flip-chip mounting the MEMS die to the first surface of the control die via electrically conductive elements.