Internal electrical contact for enclosed MEMS devices

• US 8,564,076 B1
• Filed: 01/30/2013
• Issued: 10/22/2013
• Est. Priority Date: 01/30/2013
• Status: Active Grant

• Current Assignee: Invensense Incorporated (TDK Corporation)
• Original Assignee: Invensense Incorporated (TDK Corporation)
• Inventors: Huang, Kegang, Lim, Martin, Daneman, Michael J., Seeger, Joseph, Shin, Jongwoo
• Primary Examiner(s): Malsawma, Lex
• Application Number:
  US13/754,462
• Time in Patent Office: 265 Days
• Field of Search: 257/414, 257/E23.016
• US Class Current: 257/414
• CPC Class Codes: B81B 2207/098 Arrangements not provided for in groups B81B2207/092 - B81B2207/097
• CPC Class Codes: B81B 7/0064 for protecting against electromagnetic or electrostatic interferences
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 1/00301 Connecting electric signal lines from the MEMS device with external electrical signal lines, e.g. through vias
• 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 2203/019 characterised by the material or arrangement of seals between parts
• CPC Class Codes: B81C 2203/031 Anodic bondings

Abstract

A MEMS device is disclosed. The MEMS device comprises a MEMS substrate. The MEMS substrate includes a first semiconductor layer connected to a second semiconductor layer with a dielectric layer in between. MEMS structures are formed from the second semiconductor layer and include a plurality of first conductive pads. The MEMS device further includes a base substrate which includes a plurality of second conductive pads thereon. The second conductive pads are connected to the first conductive pads. Finally, the MEMS device includes a conductive connector formed through the dielectric layer of the MEMS substrate to provide electrical coupling between the first semiconductor layer and the second semiconductor layer. The base substrate is electrically connected to the second semiconductor layer and the first semiconductor layer.

Claims

1. A MEMS device comprising:

a MEMS substrate, the MEMS substrate includes a first semiconductor layer, a second semiconductor layer and a dielectric layer in between;

wherein MEMS structures are formed from the second semiconductor layer and includes a plurality of first conductive pads;

a base substrate which includes a plurality of second conductive pads thereon;

wherein the second conductive pads are connected to the first conductive pads; and

a conductive connector formed through the dielectric layer of the MEMS substrate to provide electrical coupling between the first semiconductor layer and the second semiconductor layer, whereby the base substrate is electrically connected to the second semiconductor layer and the first semiconductor layer.

2. The MEMS device of claim 1, wherein the plurality of first conductive pads comprise germanium.

3. The MEMS device of claim 1, wherein the plurality of second conductive pads comprise aluminum.

4. The MEMS device of claim 1, wherein the MEMS substrate includes one or more etched vias filled by conductive material to form the conductive connector.

5. The MEMS device of claim 4, wherein the one or more etched vias are formed through both the second semiconductor layer and the dielectric layer.

6. The MEMS device of claim 4, wherein the conductive material filling the one or more vias comprises any of polysilicon, germanium, and tungsten.

7. The MEMS device of claim 4, wherein the conductive material filling the one or more vias comprises any of aluminum, titanium, and titanium nitride.

8. The MEMS device of claim 1 further comprising a seal ring, the seal ring comprising a continuous ring to form an enclosure surrounding the MEMS structures and formed by a connection of one of the first conductive pads and one of the second conductive pads.

9. The MEMS device of claim 8, wherein the one of the first conductive pads is electrically connected to the first semiconductor layer.

10. The MEMS device of claim 8, wherein the one of the first conductive pads is not electrically connected to the first semiconductor layer.

11. The MEMS device of claim 8, wherein the conductive connector is positioned in the enclosure of the seal ring.

12. The MEMS device of claim 8, wherein the conductive connector is positioned outside the enclosure of the seal ring.

13. The MEMS device of claim 8, wherein the conductive connector is positioned within the seal ring.

14. The MEMS device of claim 8, wherein the seal ring provides a hermetic seal.

15. The MEMS device of claim 1, wherein the connection between the first conductive pad and second conductive pad is a eutectic bond.

16. The MEMS device of claim 1, wherein the MEMS structures are electrically isolated from the first semiconductor layer.

17. The MEMS device of claim 1, wherein surface of the first semiconductor layer facing the second semiconductor layer includes cavities therein.

18. The MEMS device of claim 1, wherein the first semiconductor layer and the second semiconductor layer comprise any of single crystal silicon materials or polysilicon materials.