Method of integrating MEMS device with low-resistivity silicon substrates

• US 6,559,530 B2
• Filed: 09/19/2001
• Issued: 05/06/2003
• Est. Priority Date: 09/19/2001
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Hinzel, David H., Linder, Lloyd F., Goldsmith, Charles L.
• Primary Examiner(s): Jackson, Jerome
• Application Number:
  US09/956,402
• Publication Number:
  US 20030054584A1
• Time in Patent Office: 594 Days
• Field of Search: 257/684, 257/728, 257/415
• US Class Current: 257/684
• CPC Class Codes: B81B 7/0006 Interconnects
• CPC Class Codes: B81B 7/007 Interconnections between the MEMS and external electrical signals
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/13025 the bump connector being disposed on a via connection of the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2924/10158 at the passive surface

Abstract

A method of integrating MEMS devices with non-MEMS circuitry requires fabricating non-MEMS devices on a substrate in a conventional fashion. A thick dielectric layer is deposited on the completed devices, and the MEMS devices fabricated on the dielectric layer. Vias through the dielectric layer interconnect the MEMS devices to the non-MEMS electronics. The interposed dielectric layer allows the common substrate to have characteristics that best suit the non-MEMS components, without degrading the MEMS performance. Another approach involves bonding together two separate wafers—one for the MEMS devices and one for non-MEMS electronics. A package lid, having filled vias formed therethrough, is bonded to the MEMS wafer, sealing the MEMS devices within. The non-MEMS wafer is mounted to the lid, with the vias effecting the necessary interconnections between the two wafers. This enables the MEMS devices and the non-MEMS electronics to function as a single IC, while retaining the established processes associated with each component type.

Claims

1. A device which includes microelectromechanical system (MEMS) devices and non-MEMS devices fabricated on respective substrates, comprising:

a first substrate on which at least one MEMS device is fabricated,

a lid bonded to said first substrate which encapsulates said MEMS devices,

at least one via through said lid, each of said vias filled with a conductive material, and

a second substrate on which at least one non-MEMS device is fabricated, said second substrate bonded to the side of said lid opposite said first substrate such that at least one of said MEMS devices is interconnected to at least one of said devices on said second substrate via at least one of said vias.

2. The device of claim 1, wherein said lid is glass.

3. The device of claim 1, wherein said lid is anodically bonded to said first substrate.

4. The device of claim 1, wherein said lid hermetically seals said MEMS devices.

5. The device of claim 1, wherein said first substrate has a resistivity of >

10,000 Ω

-cm.

6. The device of claim 1, wherein said second substrate comprises silicon-germanium (SiGe).

7. The device of claim 1, wherein said first substrate further comprises vias filled with a conductive material such that, when said device is mounted to a printed circuit board (PCB), said vias through said first substrate interconnect said device to said PCB.

8. A device which includes microelectromechanical system (MEMS) devices and non-MEMS devices fabricated on respective substrates, comprising:

a high-resistivity substrate on which at least one MEMS device is fabricated and which includes at least one via therethrough, said at least one via filled with a conductive material,

a glass lid anodically bonded to said first substrate which hermetically seals said MEMS devices,

at least one via through said lid, each of said vias backfilled with a conductive material, and

a low-resistivity substrate on which at least one non-MEMS device is fabricated, said low-resistivity substrate bonded to the side of said lid opposite said high-resistivity substrate such that at least one of said MEMS devices is interconnected to at least one of said non-MEMS devices on said high-resistivity second substrate via at least one of said vias.

9. The device of claim 8, wherein said low-resistivity substrate comprises silicon-germanium (SiGe).

10. The device of claim 8, wherein said high-resistivity substrate has a resistivity of >

10,000 Ω

-cm.

11. The device of claim 8, further comprising a printed circuit board (PCB), said device mounted to said PCB such that said at least one via through said first substrate interconnects said device to said PCB.