MICROELECTRONIC PACKAGES HAVING SPLIT GYROSCOPE STRUCTURES AND METHODS FOR THE FABRICATION THEREOF

• US 20170038209A1
• Filed: 08/15/2014
• Published: 02/09/2017
• Est. Priority Date: 08/15/2014
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Philip H. Bowles, Stephen R. Hooper
• Inventors: BOWLES, PHILIP H., HOOPER, STEPHEN R.
• Granted Patent: US 9,891,244 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81B 2203/051 Translation according to an axis parallel to the substrate
• CPC Class Codes: B81B 2203/053 Translation according to an axis perpendicular to the substrate
• CPC Class Codes: B81B 7/0074 3D packaging, i.e. encapsulation containing one or several MEMS devices arranged in planes non-parallel to the mounting board
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 2203/0109 Bonding an individual cap on the substrate
• CPC Class Codes: B81C 2203/0118 Bonding a wafer on the substrate, i.e. where the cap consists of another wafer
• CPC Class Codes: B81C 2203/035 Soldering
• CPC Class Codes: B81C 3/001 Bonding of two components
• CPC Class Codes: G01C 19/5783 Mountings or housings not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/18 in two or more dimensions

Abstract

Methods for fabricating microelectronic packages and microelectronic packages having split gyroscope structures are provided. In one embodiment, the microelectronic package includes a first Microelectromechanical Systems (MEMS) die having a first MEMS gyroscope structure thereon. The microelectronic package further includes a second MEMS die, which has a second MEMS gyroscope structure thereon and which is positioned in a stacked relationship with the first MEMS die. The first and second MEMS gyroscope structures overlap as taken along a first axis orthogonal to a principal axis of the first MEMS die.

Claims

1. A microelectronic package, comprising:

a first Microelectromechanical Systems (MEMS) die having a first MEMS gyroscope structure thereon; and

a second MEMS die having a second MEMS gyroscope structure thereon and positioned in a stacked relationship with the first MEMS die, the first and second MEMS gyroscope structures overlapping as taken along a first axis orthogonal to a principal surface of the first MEMS die.

2. The microelectronic package of claim 1 wherein the first and second MEMS gyroscope structures are sensitive along mutually exclusive, orthogonal axes such that the first and second MEMS gyroscope structures collectively provide the functionality of a three axis gyroscope.

3. The microelectronic package of claim 2 wherein the first MEMS gyroscope structure is sensitive along a first sense axis substantially orthogonal to the first MEMS die, and wherein the second gyroscope structure is sensitive along second and third axes orthogonal to the first axis.

4. The microelectronic package of claim 1 further comprising a non-gyroscope MEMS sensor formed on the first MEMS die proximate the first MEMS gyroscope structure.

5. The microelectronic package of claim 4 wherein the non-gyroscope MEMS sensor comprises an accelerometer located laterally adjacent the first MEMS gyroscope structure.

6. The microelectronic package of claim 4 wherein the planform surface area of the second MEMS gyroscope structure is greater than the planform surface area of the first MEMS gyroscope structure and greater than the planform surface area of the non-gyroscope MEMS sensor.

7. The microelectronic package of claim 1 wherein the first and second MEMS gyroscope structures are sensitive along at least one common sense axis, and wherein the first MEMS gyroscope structure has sensitivity greater than the sensitivity of the second MEMS gyroscope structure.

8. The microelectronic package of claim 1 further comprising:

a first hermetic cavity enclosing the first MEMS gyroscope structure; and

a second hermetic cavity enclosing the second MEMS gyroscope structure and fluidly coupled to the first hermetic cavity.

9. The microelectronic package of claim 8 wherein the first and second hermetic cavities contain a first pressure, and wherein the microelectronic package further comprises:

a non-gyroscope MEMS sensor formed on the first MEMS die proximate the first MEMS gyroscope structure; and

a third hermetic cavity enclosing the non-gyroscope MEMS sensor and containing a second pressure greater than the first pressure.

10. The microelectronic package of claim 8 further comprising:

a vent hole fluidly coupling the first and second hermetic cavities and formed through the first MEMS die; and

a cap piece sealingly bonded to the first MEMS die opposite the second MEMS die.

11. The microelectronic package of claim 8 further comprising:

a cap piece sealingly bonded between the first and second MEMS die; and

a vent hole fluidly coupling the first and second hermetic cavities and formed through the cap piece.

12. The microelectronic package of claim 1 further comprising a cap piece sealingly bonded to the first MEMS die, the cap piece positioned in a stacked relationship with the first and second MEMS die such that:

(i) the cap piece is disposed between the first and second MEMS die, or (ii) the first MEMS die is disposed between the cap piece and the second MEMS die.

13. The microelectronic package of claim 12 wherein the first MEMS die, the second MEMS die, and the cap piece comprise singulated pieces of a first MEMS wafer, a second MEMS wafer, and a cap piece wafer, respectively.

14. A microelectronic package, comprising:

a first Microelectromechanical Systems (MEMS) die having a first MEMS gyroscope structure and a MEMS accelerometer formed thereon;

a second MEMS die having a second MEMS gyroscope structure thereon and positioned in a stacked relationship with the first MEMS die;

a first hermetic cavity enclosing the first MEMS gyroscope structure and containing a first pressure;

a second hermetic cavity enclosing the second MEMS gyroscope structure, fluidly coupled to the first hermetic cavity, and containing the first pressure; and

a third hermetic cavity enclosing the MEMS accelerometer and containing a second pressure greater than the first pressure.

15. The microelectronic package of claim 14 wherein the microelectronic package has a centerline, wherein the first MEMS gyroscope structure is sensitive along a first axis parallel to the centerline, wherein the second MEMS gyroscope structure sensitive along second and third axes orthogonal to the first axis, and wherein the accelerometer is sensitive along the first, second, and third axes.

16. The microelectronic package of claim 14 further comprising:

a cap piece sealingly bonded to the first MEMS die; and

a vent hole fluidly coupling the first and second hermetic cavities and formed through one of the cap piece and the first MEMS die.

17. A method for fabricating a microelectronic package, comprising:

obtaining a first Microelectromechanical Systems (MEMS) wafer comprised of a first plurality of MEMS die, each having a first MEMS gyroscope structure thereon;

positioning the first MEMS wafer over a second MEMS wafer comprised of a second plurality of MEMS die, each having a second MEMS gyroscope structure thereon;

bonding the first and second MEMS wafers to produce a multi-wafer stack; and

singulating the multi-wafer stack to produce a plurality of microelectronic packages each including first and second MEMS gyroscope structures carried by first and second MEMS die, respectively.

18. The method of claim 17 wherein the first MEMS wafer is positioned over and bonded to the second MEMS wafer such that, for each of the plurality of microelectronic packages produced by singulation of the multi-wafer stack, the first and second MEMS gyroscope structures overlap as taken along axis orthogonal to principal surfaces of the first and second MEMS die.

19. The method of claim 17 wherein bonding comprises bonding the first MEMS wafer, the second MEMS wafer, and a cap piece wafer in a stacked relationship to produce the multi-wafer stack;

and wherein each microelectronic package produced by singulation of the multi-wafer stack further includes a cap piece bonded to the first MEMS die.

20. The method of claim 19 wherein the first MEMS wafer, the second MEMS wafer, and the cap piece wafer are bonded such that the first and second MEMS gyroscope structures are enclosed by first and second hermetic cavities, respectively.