Covers for micromechanical sensors and other semiconductor devices

• US 5,610,431 A
• Filed: 05/12/1995
• Issued: 03/11/1997
• Est. Priority Date: 05/12/1995
• Status: Expired due to Fees

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Martin, Jacob H.
• Primary Examiner(s): Crane, Sara W.
• Assistant Examiner(s): POTTER, ROY KARL
• Application Number:
  US08/440,528
• Time in Patent Office: 669 Days
• Field of Search: 257/704, 257/417, 257/626, 257/418, 257/419, 257/415
• US Class Current: 257/415
• CPC Class Codes: G01P 1/023 for acceleration measuring devices
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/10253 Silicon [Si]

Abstract

A cover for a micromechanical device through which input/output connections to the device are made. The cover includes at least two doped semiconductor standoffs supporting an insulative layer. One or more metalized vias extend from a top surface of the insulative layer, or from a bottom surface of the base, to a respective standoff. Electrical connection is made to the covered device through the metalized vias and doped semiconductor standoffs. The covered chip may be vacuum sealed by providing a ring-like standoff which borders the covered device when the cover is bonded to the base. The resulting covered chip is adaptable for various chip mounting techniques, including flip chip mounting, side mounting combined with either tape automated bonding (TAB) or conductive epoxy connections, or epoxy chip attachment with wire bonding connections. In one embodiment, conductive bumps are formed on the top surface of the insulative cover layer to accommodate flip chip mounting. In another embodiment, conductive traces are run across the top surface of the insulative layer to interconnect the vias to respective edge positioned pads which are electrically interconnected by one of various techniques to pads on a wiring board.

Claims

1. A cover for a micromechanical device comprising:

at least two conductive supports; and

an insulative layer having a top surface and a bottom surface disposed over said at least two conductive supports, said insulative layer having at least one metalized via disposed therethrough to extend from said top insulative layer surface to a respective one of said conductive supports.

2. The cover recited in claim 1 wherein said at least two conductive supports are comprised of silicon doped with boron.

3. The cover recited in claim 1 wherein said insulative layer is comprised of PYREX™

.

4. The cover recited in claim 1 further comprising at least one conductive bump disposed on said top surface of said insulative layer in electrical contact with said at least one metalized via.

5. The cover recited in claim 1 wherein said top surface of said insulative layer has at least one conductive trace thereon for electrically interconnecting said at least one metalized via to a conductive pad.

6. The cover recited in claim 5 wherein said conductive pad is positioned adjacent to an edge of said insulative layer.

7. A micromechanical structure comprising:

a base supporting a micromechanical device; and

a cover bonded to a top surface of said base, said cover comprising;

at least two conductive supports; and

an insulative layer having a top surface and a bottom surface disposed over said at least two conductive supports, said insulative layer having a metalized via disposed therethrough to extend from said top surface of said insulative layer to a respective one of said conductive supports.

8. The micromechanical structure recited in claim 7 wherein said device is a micromechanical inertial sensor.

9. The micromechanical structure recited in claim 7 wherein said at least two conductive supports are comprised of silicon doped with boron.

10. The micromechanical structure recited in claim 7 wherein said cover is anodically bonded to said base.

11. The micromechanical structure recited in claim 7 wherein said cover is diffusion bonded to said base.

12. The micromechanical structure recited in claim 7 wherein said insulative layer is comprised of PYREX™

.

13. The micromechanical structure recited in claim 7 wherein said base is comprised of PYREX™

.

14. The micromechanical structure recited in claim 7 further comprising at least one conductive bump disposed on said top surface of said insulative layer in electrical contact with said at least one metalized via.

15. The micromechanical structure recited in claim 7 wherein said top surface of said insulative layer has at least one conductive trace thereon for electrically interconnecting said at least one via to a conductive pad.

16. The micromechanical structure recited in claim 15 wherein said conductive pad is positioned adjacent to an edge of said micromechanical structure.