MEMS COMPONENTS AND METHOD OF WAFER-LEVEL MANUFACTURING THEREOF

• US 20160229685A1
• Filed: 09/19/2014
• Published: 08/11/2016
• Est. Priority Date: 07/08/2013
• Status: Active Application

• Current Assignee: Motion Engine inc
• Original Assignee: Motion Engine inc
• Inventors: Boysel, Robert Mark
• Granted Patent: US 10,273,147 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 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2207/012 the micromechanical device and the control or processing electronics being separate parts in the same package
• CPC Class Codes: B81B 2207/015 the micromechanical device and the control or processing electronics being integrated on the same substrate
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81B 2207/095 through the lid
• CPC Class Codes: B81B 7/007 Interconnections between the MEMS and external electrical signals
• CPC Class Codes: B81C 1/00238 Joining a substrate with an electronic processing unit and a substrate with a micromechanical structure
• CPC Class Codes: B81C 2201/013 Etching
• CPC Class Codes: B81C 2203/0792 Forming interconnections between the electronic processing unit and the micromechanical structure

Abstract

A MEMS and a method of manufacturing MEMS components are provided. The method includes providing a MEMS wafer stack including a top cap wafer, a MEMS wafer and optionally a bottom cap wafer. The MEMS wafer has MEMS structures patterned therein. The MEMS wafer and the cap wafers include insulated conducting channels forming insulated conducting pathways extending within the wafer stack. The wafer stack is bonded to an integrated circuit wafer having electrical contacts on its top side, such that the insulated conducting pathways extend from the integrated circuit wafer to the outer side of the top cap wafer. Electrical contacts on the outer side of the top cap wafer are formed and are electrically connected to the respective insulated conducting channels of the top cap wafer. The MEMS wafer stack and the integrated circuit wafer are then diced into components having respective sealed chambers and MEMS structures housed therein.

Claims

1. A method of manufacturing MEMS components, comprising the steps of:

bonding a MEMS wafer stack to an integrated circuit wafer, the MEMS wafer stack having an inner side and an outer side, the MEMS wafer stack comprising a top cap wafer and a MEMS wafer, the top cap wafer having opposed inner and outer sides and insulated conducting channels extending through the top cap wafer between the inner side and the outer sides;

the MEMS wafer having opposed first and second sides and insulated conducting channels extending through the MEMS wafer between the first side and the second side of the MEMS wafer, the MEMS wafer also including MEMS structures patterned therein, the top cap wafer and the MEMS wafer providing respective top and side walls for defining at least part of hermetically sealed chambers housing the corresponding MEMS structures, the inner side of the top cap wafer facing the first side of the MEMS wafer and the insulated conducting channels of the top cap wafer and of the MEMS wafer being aligned to form insulated conducting pathways;

integrated circuit wafer has an inner side with electrical contacts, such that the inner side of the MEMS wafer stack is bonded to the inner side of the integrated circuit wafer such that the insulated conducting pathways extend from the electrical contacts of the integrated circuit wafer, through the MEMS wafer, through the top cap wafer, to the outer side of the MEMS wafer stack;

forming electrical contacts on the outer side of the top cap wafer, the electrical contacts being respectively connected to the insulated conducting channels of the top cap wafer; and

dicing the MEMS wafer stack and the integrated circuit wafer into MEMS components such that the MEMS components comprise the hermetically sealed chambers and MEMS structures.

2. The method according to claim 1, wherein step a) comprises:

patterning the insulated conducting channels on the inner side of the top cap wafer such that the insulated conducting channels extend from the inner side of the top cap wafer and partially through the top cap wafer;

bonding the first side of the MEMS wafer to the inner side of the top cap wafer; and

patterning the insulated conducting channels, the MEMS structures and the sidewalls of the sealed chambers on the second side of the MEMS wafer and through the MEMS wafer.

3. The method according to claim 2, comprising a step of removing a portion of the outer side of the top cap wafer so as to isolate the insulated conducting channels, said step being performed after the step of patterning the insulated conducting channels or after the step of bonding the MEMS wafer to the integrated circuit wafer.

4. The method according to claim 1 wherein the wafer stack further includes a bottom cap wafer having opposed inner and outer sides and insulated conducting channels extending through the bottom cap wafer between the inner side and the outer side, the inner side of the bottom cap wafer facing the second side of the MEMS wafer, the insulated conducting channels of the bottom cap wafer being respectively aligned with the insulated conducting channels of the MEMS wafer and forming part of the insulated conducting pathways, and wherein the bonding step further comprises bonding the outer side of the bottom cap wafer to the inner side of the integrated circuit wafer, the outer side of bottom cap wafer corresponding to the outer side of wafer stack.

5. The method according to claim 4, wherein step a) comprises the sub-steps of:

patterning the insulated conducting channels of the top cap wafer on the inner side of the top cap wafer such that the insulated conducting channels extend from the inner side of the top cap wafer and partially through the top cap wafer, and patterning the insulated conducting channels of the bottom cap wafer on the inner side thereof such that the insulated conducting channels extend from the inner side of the bottom cap wafer and partially through the bottom cap wafer;

bonding the first side of the MEMS wafer to the inner side of the top cap wafer;

patterning the insulated conducting channels, the MEMS structures and the sidewalls of the sealed chambers on the second side of the MEMS wafer and through the MEMS wafer; and

bonding the second side of the MEMS wafer to the inner side of the bottom cap wafer.

6. The method according to claim 5, comprising a step of removing a portion of the outer side of the bottom and top cap wafers so as to isolate their respective insulated conducting channels, said step being performed after the step of bonding the second side of the MEMS wafer step.

7. The method according to claim 4, wherein step of forming electrical contacts comprises forming electrical contacts on the outer side of the bottom cap wafer, the electrical contacts of the bottom cap wafer being respectively connected to the insulated conducting pathways.

8. The method according to claim 7, wherein step of bonding the MEMS wafer stack is performed by solder-bonding the electrical contacts of the bottom cap wafer to electrical contacts of the integrated circuit wafer.

9. The method according to claim 1, comprising a step of bonding one of the MEMS components obtained from dicing of the MEMS wafer stack to a printed circuit board (PCB).

10. The method according to claim 1, wherein, the insulated conducting channels of the top cap wafer and of the MEMS wafer are fabricated using a trench fill process.

11. The method according to claim 1, wherein the top and bottom cap wafers are made of a silicon material, and the insulated conducting channels of the top cap wafer and of the MEMS wafer are fabricated by etching trenches around a conductive plug of the silicon material, and by filling the trenches of the top cap wafer with an insulating material.

12. The method according to claim 1, wherein the insulated conducting channels of at least one of the top cap wafer and the MEMS wafer is fabricated by etching channels into the corresponding top cap wafer or the MEMS wafer, lining the channels with an insulating material and filling the channels with a conductive material.

13. A MEMS (microelectromechanical system) component, comprising:

a top cap wafer having an inner side and an outer side and insulated conducting channels extending between the inner side and the outer side through a thickness of the top cap wafer, the outer side being provided with electrical contacts connected to the insulated conducting channels;

a MEMS wafer having a first side and a second side and insulated conducting channels extending between the first side and the second side through a thickness of the MEMS wafer, the MEMS wafer including a MEMS structure patterned therein, the inner side of the top cap wafer and the first side of the MEMS wafer being bonded with respective insulated conducting channels aligned to form insulated conducting pathways; and

an integrated circuit wafer having an inner side and an outer side, the inner side of the integrated circuit wafer including electrical contacts, the inner side of the integrated circuit wafer facing the second side of the MEMS wafer such that electrical contacts of the integrated circuit wafer are electrically connected to the electrical contacts of the top cap wafer with the insulated conducting pathways, the top cap wafer and the MEMS wafer providing a top cap wafer side wall and a MEMS wafer side wall defining at least part of a hermetically sealed chamber that houses the MEMS structure.

14. The MEMS component according to claim 13, wherein the top cap wafer and the MEMS wafer comprise a silicon material and the integrated circuit wafer is a CMOS wafer.

15. The MEMS component according to claim 13, wherein conducting portions of the insulated conducting channels of the top cap wafer include filled trenches.

16. The MEMS component according to claim 13, wherein the insulated conducting channels of the top cap wafer and of the MEMS wafer comprise a conductive plug of a silicon material surrounded by insulating material and/or by an air gap.

17. The MEMS component according to claim 13, wherein the insulated conducting channels of the top cap wafer and/or of the MEMS wafer comprise etched channels lined with an insulating material and filled with a conductive material.

18. The MEMS component according to claim 13, comprising a bottom cap wafer having an inner side and an outer side and insulated conducting channels extending through the bottom cap wafer between the inner side and the outer side, the inner side of the bottom cap wafer being bonded to the second side of the MEMS wafer, the insulated conducting channels of the bottom cap wafer being respectively aligned with the insulated conducting channels of the MEMS wafer and forming part of the insulated conducting pathways, the outer side of the bottom cap wafer being bonded to the integrated circuit wafer, the insulated conducting pathways extending from the electrical contacts of the integrated circuit wafer and successively through the bottom cap wafer, the MEMS wafer and the top cap wafer to the electrical contacts of the top cap wafer.

19. The MEMS component according to claim 13, comprising at least one of an inertial sensor, an accelerometer, a gyroscope and a pressure sensor.

20. The MEMS component according to claim 18, wherein at least one of the top cap wafer and the bottom cap wafer comprises:

additional electrical contacts on the outer side of said at least one of the top cap wafer and the bottom cap wafer, said additional electrical contacts being electrically connected to integrated circuits of the integrated circuit wafer; and

electrodes operatively coupled to the MEMS structure and to the additional electrical contacts, respectively.