Wafer encapsulated microelectromechanical structure and method of manufacturing same

Abstract

There are many inventions described and illustrated herein. In one aspect, the present inventions relate to devices, systems and/or methods of encapsulating and fabricating electromechanical structures or elements, for example, accelerometer, gyroscope or other transducer (for example, pressure sensor, strain sensor, tactile sensor, magnetic sensor and/or temperature sensor), filter or resonator. The fabricating or manufacturing microelectromechanical systems of the present invention, and the systems manufactured thereby, employ wafer bonding encapsulation techniques.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the course of the detailed description to follow, reference will be made to the attached drawings. These drawings show different aspects of the present inventions and, where appropriate, reference numerals illustrating like structures, components, materials and/or elements in different figures are labeled similarly. It is understood that various combinations of the structures, components, materials and/or elements, other than those specifically shown, are contemplated and are within the scope of the present inventions.

FIG. 1A is a block diagram representation of a mechanical structure disposed on a substrate and encapsulated via at least a second substrate;

FIG. 1B is a block diagram representation of a mechanical structure and circuitry, each disposed on one or more substrates and encapsulated via a substrate;

FIG. 2 illustrates a top view of a portion of a mechanical structure of a conventional resonator, including moveable electrode, fixed electrode, and a contact;

FIG. 3 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the first substrate employs an SOI wafer;

FIGS. 4A-4G illustrate cross-sectional views (sectioned along dotted line A-A′ of FIG. 2) of the fabrication of the mechanical structure of FIGS. 2 and 3 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 5 illustrates a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2, wherein microelectromechanical system includes electronic or electrical circuitry in conjunction with micromachined mechanical structure of FIG. 2, in accordance with an exemplary embodiment of the present inventions;

FIGS. 6A-6D illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 5 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIGS. 7A-7C, and 8A and 8B illustrate cross-sectional views of two exemplary embodiments of the fabrication of the portion of the microelectromechanical system of FIG. 5 using processing techniques wherein electronic or electrical circuitry (at various stages of completeness) is formed in the second substrate prior to encapsulating the mechanical structure via securing the second substrate to the first substrate;

FIG. 9 illustrates a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2, wherein micromachined mechanical structure of FIG. 2 includes an isolation trench to electrically isolate the contact, in accordance with an exemplary embodiment of the present inventions;

FIGS. 10A-10I illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 9 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 11 illustrates a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2, wherein micromachined mechanical structure of FIG. 2 includes isolation regions and an isolation trench (aligned therewith) to electrically isolate the contact, in accordance with an exemplary embodiment of the present inventions;

FIGS. 12A-12J illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 11 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 13A illustrates a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2, wherein micromachined mechanical structure of FIG. 2 includes isolation regions and an isolation trench (aligned therewith), including an oppositely doped semiconductor (relative to the conductivity of second substrate 14b), to electrically isolate the contact, in accordance with an exemplary embodiment of the present inventions;

FIGS. 13B and 13C illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 13A at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 14 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an embodiment of the present inventions wherein the microelectromechanical system employs three substrates;

FIGS. 15A-15H illustrate cross-sectional views (sectioned along dotted line A-A′ of FIG. 2) of the fabrication of the mechanical structure of FIGS. 2 and 14 at various stages of a process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 16 illustrates a cross-sectional view of an embodiment of the fabrication of the microelectromechanical system of FIG. 14 wherein electronic or electrical circuitry (after fabrication) is formed in the third substrate according to certain aspects of the present inventions;

FIG. 17 illustrates a cross-sectional view of an exemplary embodiment of the present inventions of the microelectromechanical system including a plurality of micromachined mechanical structures wherein a first micromachined mechanical structure is formed in the second substrate and a second micromachined mechanical structure is formed in the third substrate wherein a fourth substrate encapsulates one or more of the micromachined mechanical structures according to certain aspects of the present inventions;

FIG. 18 illustrates a cross-sectional view of an exemplary embodiment of the present inventions of the microelectromechanical system including a plurality of micromachined mechanical structures wherein a first micromachined mechanical structure is formed in the second substrate and a second micromachined mechanical structure is formed in the third substrate wherein a fourth substrate encapsulates one or more of the micromachined mechanical structures and includes electronic or electrical circuitry according to certain aspects of the present inventions;

FIG. 19 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates and cavities are formed in the first and third substrates;

FIGS. 20A-20H illustrate cross-sectional views (sectioned along dotted line A-A′ of FIG. 2) of the fabrication of the mechanical structure of FIGS. 2 and 19 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 21 illustrates a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2, wherein the first cavity is formed in the second substrate and a second cavity is formed in a third substrate according to certain aspects of the present inventions;

FIG. 22 illustrates a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2, wherein the first and second cavities are formed in the second substrate, according to certain aspects of the present inventions;

FIG. 23 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates and the second and third substrates include the same conductivity types;

FIGS. 24A-24I illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 23 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 25 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates and the first and second substrates include the same conductivity types;

FIGS. 26A-26H illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 25 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 27 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates which include the same conductivity types;

FIGS. 28A-28I illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 27 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 29 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates which include the same conductivity types;

FIGS. 30A-30I illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 29 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIGS. 31A-31D illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 27 at various stages of an exemplary process that employs grinding and/or polishing to provide a desired surface, according to certain aspects of the present inventions;

FIG. 32 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates;

FIGS. 33A-33I illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 32 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 34 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates wherein an insulative layer is disposed between each of the substrates;

FIGS. 35A-35L illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 34 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 36 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates wherein an insulative layer is disposed between two of the substrates;

FIGS. 37A-37I illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 36 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 38 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates wherein an insulative layer is disposed between two of the substrates and isolation trenches and regions electrically isolate the contact;

FIGS. 39A-39K illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 38 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 40 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates wherein an intermediate layer (for example, a native oxide layer) is disposed between two of the substrates;

FIGS. 41A-41H illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 40 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIGS. 42A and 42B are cross-sectional views (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of exemplary embodiments of the present inventions wherein the microelectromechanical system employs three substrates wherein an intermediate layer (for example, a native oxide layer) is disposed (for example, deposited or grown) between two of the substrates;

FIGS. 43A-43K illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical systems of FIGS. 42A and 42B at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 44 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates and the processing techniques include alternative processing margins;

FIGS. 45A-45I illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 44 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 46A is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates and the processing techniques include alternative processing margins wherein the isolation trenches include an over etch;

FIG. 46B is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates and a selected trench includes alternative processing margins;

FIGS. 47A-47D and 48A-48C are cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an embodiment of the present inventions having alternative exemplary processing techniques, flows and orders thereof;

FIGS. 49A-49G, 50A-50G and 51A-51J are cross-sectional views (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of exemplary embodiments of the present inventions having alternative processing techniques, flows and orders thereof relative to one or more of substrates;

FIG. 52 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates wherein isolation regions are implanted in a cover substrate to electrically isolate the contact;

FIGS. 53A-53H illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 52 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 54 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein the microelectromechanical system employs three substrates wherein isolation regions include an insulation material (for example, a silicon nitride or silicon dioxide);

FIGS. 55A-55K illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 54 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 56 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein a contact area is etched and formed in one of the “cover” substrate to provide for electrical conductivity with the an underlying contact area;

FIGS. 57A-57J illustrate cross-sectional views of an exemplary flow of the fabrication of the portion of the microelectromechanical system of FIG. 56 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 58 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of an exemplary embodiment of the present inventions wherein bonding material and/or a bonding facilitator material is employed between substrates;

FIGS. 59A-59G and 59J-59L illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 58 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIG. 60 is a cross-sectional view (sectioned along dotted line A-A′ of FIG. 2) of a portion of the moveable electrode, fixed electrode, and the contact of FIG. 2 of another exemplary embodiment of the present inventions wherein bonding material and/or a bonding facilitator material is employed between substrates;

FIGS. 61A-61K illustrate cross-sectional views of the fabrication of the portion of the microelectromechanical system of FIG. 58 at various stages of an exemplary process that employs an encapsulation technique according to certain aspects of the present inventions;

FIGS. 62-64 illustrates cross-sectional views of several embodiments of the fabrication of microelectromechanical systems of the present inventions wherein the microelectromechanical systems include electronic or electrical circuitry formed in a substrate, according to certain aspects of the present inventions; and

FIGS. 65 and 66A-66F are block diagram illustrations of various embodiments of the microelectromechanical systems of the present inventions wherein the microelectromechanical systems includes at least three substrates wherein one or more substrates include one or more micromachined mechanical structures and/or electronic or electrical circuitry, according to certain aspects of the present inventions.

Claims

1. A microelectromechanical device comprising: a first substrate;a chamber;a microelectromechanical structure, wherein the microelectromechanical structure is (i) formed from a portion of the first substrate and (ii) at least partially disposed in the chamber;a second substrate, bonded to the first substrate, wherein a surface of the second substrate forms a wall of the chamber; anda contact, wherein: a first portion of the contact is (i) formed from a portion of the first substrate and (ii) at least a portion thereof is disposed outside the chamber; anda second portion of the contact is formed from a portion of the second substrate.

2. The microelectromechanical device of claim 1 wherein the second substrate includes polycrystalline silicon, porous polycrystalline silicon, amorphous silicon, silicon carbide, silicon/germanium, germanium, or gallium arsenide.

3. The microelectromechanical device of claim 2 wherein the first substrate includes polycrystalline silicon, porous polycrystalline silicon, amorphous silicon, silicon carbide, silicon/germanium, germanium, or gallium arsenide.

4. The microelectromechanical device of claim 2 wherein: the first portion of the contact is a semiconductor material having a first conductivity;the second substrate is a semiconductor material having a second conductivity; andthe second portion of the contact is a semiconductor material having the first conductivity.

5. The microelectromechanical device of claim 4 wherein the second portion of the contact is a polycrystalline or monocrystalline silicon that is counterdoped to include the first conductivity.

6. The microelectromechanical device of claim 1 further including a trench, disposed in the second substrate and around at least a portion of the second portion of the contact.

7. The microelectromechanical device of claim 6 wherein the trench includes a first material disposed therein to electrically isolate the second portion of the contact from the second substrate.

8. The microelectromechanical device of claim 6 wherein the first material is an insulation material.

9. The microelectromechanical device of claim 1 wherein the first substrate is an semiconductor on insulator substrate.

10. The microelectromechanical device of claim 1 wherein the first and second substrates are bonded using fusion bonding, anodic-like bonding, silicon direct bonding, soldering, thermo compression, thermo-sonic, laser bonding and/or glass reflow.

11. A microelectromechanical device comprising: a first substrate;a second substrate, wherein the second substrate is bonded to the first substrate;a chamber;a microelectromechanical structure, wherein the microelectromechanical structure is (i) formed from a portion of the second substrate and (ii) at least partially disposed in the chamber;a third substrate, bonded to the second substrate, wherein a surface of the third substrate forms a wall of the chamber; anda contact, wherein: a first portion of the contact is (i) formed from a portion of the second substrate and (ii) at least a portion thereof is disposed outside the chamber; anda second portion of the contact is formed from a portion of the third substrate.

12. The microelectromechanical device of claim 11 wherein the second substrate includes polycrystalline silicon, porous polycrystalline silicon, amorphous silicon, silicon carbide, silicon/germanium, germanium, or gallium arsenide.

13. The microelectromechanical device of claim 12 wherein the third substrate includes polycrystalline silicon, porous polycrystalline silicon, amorphous silicon, silicon carbide, silicon/germanium, germanium, or gallium arsenide.

14. The microelectromechanical device of claim 12 wherein: the first portion of the contact is a semiconductor material having a first conductivity;the third substrate is a semiconductor material having a second conductivity; andthe second portion of the contact is a semiconductor material having the first conductivity.

15. The microelectromechanical device of claim 14 wherein the second portion of the contact is a polycrystalline or monocrystalline silicon that is counterdoped to include the first conductivity.

16. The microelectromechanical device of claim 17 further including a trench, disposed in the third substrate and around at least a portion of the second portion of the contact.

17. The microelectromechanical device of claim 16 wherein the trench includes a first material disposed therein to electrically isolate the second portion of the contact from the third substrate.

18. The microelectromechanical device of claim 16 wherein the first material is an insulator material.

19. The microelectromechanical device of claim 16 further including an isolation region disposed in the second substrate such that the trench is aligned with and juxtaposed to the isolation region.

20. The microelectromechanical device of claim 19 wherein: the first portion of the contact is a semiconductor material having a first conductivity;the isolation region is a semiconductor material having a second conductivity; andthe second portion of the contact is a semiconductor material having the first conductivity.

21. The microelectromechanical device of claim 20 wherein the trench includes a first material disposed therein to electrically isolate the second portion of the contact from the second substrate.

22. The microelectromechanical device of claim 16 wherein the first material is a semiconductor material having the second conductivity.

23. The microelectromechanical device of claim 11 further including an isolation region, disposed in the first substrate such that the first portion of the contact is aligned with and juxtaposed to the isolation region.

24. The microelectromechanical device of claim 11 further including: a first isolation region, disposed in the first substrate such that the first portion of the contact is aligned with and juxtaposed to the first isolation region; anda second isolation region, disposed in the second substrate such that the second portion of the contact is aligned with and juxtaposed to the second isolation region.

25. The microelectromechanical device of claim 24 wherein: the first and second portions of the contact are semiconductor materials having a first conductivity; andthe first and second isolation regions are semiconductor materials having the second conductivity.

26. The microelectromechanical device of claim 25 further including a trench, disposed in the third substrate and around at least a portion of the second portion of the contact.

27. The microelectromechanical device of claim 26 wherein the trench includes a first material disposed therein to electrically isolate the second portion of the contact from the third substrate.

28. The microelectromechanical device of claim 27 wherein the trench is aligned with and juxtaposed to the second isolation region.

29. The microelectromechanical device of claim 28 wherein the first material is an insulator material.

30. The microelectromechanical device of claim 11 wherein the second and third substrates are bonded using fusion bonding, anodic-like bonding, silicon direct bonding, soldering, thermo compression, thermo-sonic, laser bonding and/or glass reflow.