MEMS package with flexible circuit interconnect

• US 6,469,909 B2
• Filed: 01/09/2001
• Issued: 10/22/2002
• Est. Priority Date: 01/09/2001
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Simmons, Richard L.
• Primary Examiner(s): Martin, David
• Assistant Examiner(s): BUI, HUNG S
• Application Number:
  US09/756,928
• Publication Number:
  US 20020089835A1
• Time in Patent Office: 651 Days
• Field of Search: 361/803, 361/776, 361/769, 361/795, 361/719, 361/741, 361/768, 174/52.4, 174/52, 174/175, 174/177, 257/48, 257/704, 257/690, 257/686, 439/71, 439/81, 439/67, 439/331
• US Class Current: 361/803
• CPC Class Codes: B81B 7/007 Interconnections between the MEMS and external electrical signals
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• 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

Abstract

A method of fabricating a package for a micro-electromechanical systems (MEMS) device. A flex circuit interconnect subassembly for the package is made by placing a flex circuit on a pad insert, attaching a carrier insert to the pad insert to deflect the lead portions of the flex circuit, and applying a cover insert to the pad insert, after the attachment of the carrier insert, to re-deflect the lead portions of the flex circuit toward the device bond sites. The flex circuit interconnect subassembly may be combined with an electronic device die/carrier subassembly to form a completed electronic device package. The flex circuit interconnect subassembly and the die/carrier subassembly are joined using mechanical interlocking layers. The invention is particularly suited for making such an electronic device die/carrier subassembly which has a MEMS die permanently affixed to a carrier. The carrier is advantageously utilized during the process of releasing a protective coating from the surface of the MEMS die which support the various MEMS components. The MEMS components on the MEMS die are hermetically sealed, such as by bonding a cover to the upper package body or the lower package body. The cover may have features such as ports which allow the MEMS components to interact with the external environment.

Claims

1. An interconnect subassembly comprising:

a first package insert;

a flex circuit placed on said first package insert, wherein said flex circuit has lead portions to interconnect with bond pads formed on an electronics device die;

a second package insert attached to said first package insert which deflects said lead portions of said flex circuit from a first plane toward a second plane; and

a third package insert applied to said first package insert which re-deflects said lead portions of said flex circuit toward the first plane.

2. An electronic device package utilizing the flex circuit interconnect subassembly of claim 1, and further comprising an electronic device die/carrier subassembly attached to the flex circuit interconnect subassembly.

3. The electronic device package of claim 2 wherein said electronic device die/carrier subassembly includes a carrier permanently affixed to a micro-electromechanical system (MEMS) die.

4. The electronic device package of claim 3 wherein said MEMS die has a first surface supporting one or more MEMS components, and a second surface which is attached to said carrier, said first surface further having had removed a protective coating overlying said one or more MEMS components.

5. The flex circuit interconnect subassembly of claim 1 wherein:

said first package insert is a generally rectangular pad insert having an interior void;

said flex circuit is generally rectangular and sized to fit an outer perimeter of said pad insert, with said lead portions of said flex circuit extending inwardly toward said interior void of said pad insert; and

said second package insert is a generally rectangular carrier insert, smaller than said pad insert, having at least one sloping surface abutting said lead portions of said flex circuit.

6. The flex circuit interconnect subassembly of claim 5 wherein said third package insert is a generally rectangular cover insert, smaller than said pad insert, at least one surface abutting said lead portions of said flex circuit.

7. The flex circuit interconnect subassembly of claim 6 wherein:

said carrier insert has surface features along a bottom surface adapted to allow mold material to flow inwardly; and

said cover insert serves as a molding dam to prevent said mold material from flowing inwardly.

8. An electronic device package utilizing the flex circuit interconnect subassembly of claim 1, and further comprising:

an electronic device die/carrier subassembly attached to the flex circuit interconnect subassembly, wherein the electronic device die/carrier subassembly includes a carrier permanently affixed to an electronic device die having a first surface supporting one or more electronic components, and a second surface which is attached to said carrier; and

a cover attached to the flex circuit interconnect subassembly, overlying said first surface of said electronic device die.

9. The electronic device package of claim 8 further comprising an overmold body encasing a portion of said electronic device package.