Micro-electro mechanical device made from mono-crystalline silicon and method of manufacture therefore

• US 20080138922A1
• Filed: 08/07/2002
• Published: 06/12/2008
• Est. Priority Date: 12/15/1999
• Status: Active Grant

• Current Assignee: Chang-Feng Wan
• Original Assignee: Chang-Feng Wan
• Inventors: Wan, Chang-Feng
• Granted Patent: US 7,541,214 B2
• Time in Patent Office: Days
• US Class Current: 438/52
• CPC Class Codes: B81B 2203/0118 Cantilevers
• CPC Class Codes: B81B 2203/0307 Anchors
• CPC Class Codes: B81B 2207/07 Interconnects
• CPC Class Codes: B81C 1/00095 Interconnects
• CPC Class Codes: B81C 2201/019 Bonding or gluing multiple substrate layers

Abstract

The present invention is related to a method for manufacturing micro-electro-mechanical systems (MEMS) having movable and stationary suspended structures formed from mono-crystalline silicon wafer or chip, bonded to a substrate wafer with an polymer adhesive layer that serves as spacer and as a sacrificial layer which is undercut by dry etch means. The substrate wafer contains electronic circuits for sensing and actuating the suspended structure by electrical means. Electrical interconnections between the suspended structures and the substrate can be made by etching through via holes in the suspended structure and the adhesive, depositing metal layers in the via holes, and removing the metal layers from outside the via holes. The metal layers in the via holes can also be used as pillars for supporting the suspended structures. This method can be used to manufacture inertial sensors.

Claims

1. (canceled)

2. (canceled)

3. (Canceled)

4. A method of manufacturing a micro-electro-mechanical (MEMS) device, comprising the steps of:

providing a substrate wafer having electrical elements, and a second wafer;

bonding said substrate wafer and said second wafer with an adhesive layer;

patterning a plurality of via holes in said second wafer and said adhesive layer;

etching said via holes through said second wafer and said adhesive layer;

depositing metal layers in said via holes to form electrical interconnects between said second wafer and said substrate wafer;

etching said second wafer;

etching said adhesive layer with undercut to said second wafer

forming suspended structures and fixed structures from seconded wafer;

wherein said electrical interconnects and/or said adhesive layer jointly or independently support or anchor said suspended structures.

5. The method of claim 4, wherein said electrical elements comprises integrated circuits and wherein said suspended structures and said electrical elements are configured to form integrated MEMS devices including accelerometers or gyroscopes.

6. A method of manufacturing a micro-electro-mechanical (MEMS) device, comprising the steps of:

providing a substrate wafer and a plurality of silicon chips;

applying an adhesive layer on said substrate wafer;

attaching said silicon chips at selected locations on said substrate wafer;

pressing said silicon chips and said substrate wafer together;

curing said adhesive to form a bond between said mono-crystalline silicon chips and said substrate wafer;

etching with patterns through said silicon chips; and

etching said adhesive layer to undercut said silicon chip to form suspended structures.

7. The method of claim 6, wherein said micro-electro-mechanical (MEMS) device is a gyroscope or an accelerometer.

8. The method of claim or 6, wherein the step of providing a substrate wafer further comprises the step of forming a plurality of polymer dot of predetermined pattern and thickness on said substrate wafer before said bonding.

9. (canceled)

10. The method of manufacturing a micro-electro-mechanical (MEMS) device, comprising the steps of:

providing a MEMS wafer that is manufactured with those steps described in claim or 6 prior to etching said adhesive layer;

providing a second wafer;

applying another layer of adhesive to said MEMS wafer;

curing said another layer of adhesive;

planarizing said another layer of adhesive;

applying yet another layer of adhesive to said MEMS wafer and/or said second wafer;

bonding said MEMS wafer with said second wafer with said another layer of adhesive to said MEMS wafer;

thinning and polishing said second wafer;

etching through said second wafer;

removing all the adhesive layers to form suspended structures.

12. The method of claim 10, further comprising the step of forming metal interconnect/pillars among said mono-crystalline layers.

11. (canceled)

13. (canceled)

14. (Canceled)

15. (Canceled)