Methods of fabrication for flip-chip image sensor packages

• US 7,122,390 B2
• Filed: 06/14/2005
• Issued: 10/17/2006
• Est. Priority Date: 08/29/2002
• Status: Expired due to Fees

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Kinsman, Larry D.
• Primary Examiner(s): CHAMBLISS, ALONZO
• Application Number:
  US11/152,519
• Publication Number:
  US 20050233502A1
• Time in Patent Office: 490 Days
• Field of Search: None
• US Class Current: 438/26
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14634 Assemblies, i.e. Hybrid structures
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/14683 Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof not peculiar thereto H01L21/00
• CPC Class Codes: H01L 27/1469 Assemblies, i.e. hybrid integration
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/15192 Resurf arrangement of the internal vias
• CPC Class Codes: H01L 31/02005 for device characterised by at least one potential jump barrier or surface barrier
• CPC Class Codes: H01L 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80

Abstract

The present invention provides flip-chip packaging for optically interactive devices such as image sensors and methods of assembly. In a first embodiment of the invention, conductive traces are formed directly on the second surface of a transparent substrate and an image sensor chip is bonded to the conductive traces. Discrete conductive elements are attached to the conductive traces and extend below a back surface of the image sensor chip. In a second embodiment, a secondary substrate having conductive traces formed thereon is secured to the transparent substrate. In a third embodiment, a backing cap having a full array of attachment pads is attached to the transparent substrate of the first embodiment or the secondary substrate of the second embodiment. In a fourth embodiment, the secondary substrate is a flex circuit having a mounting portion secured to the second surface of the transparent substrate and a backing portion bent over adjacent to the back surface of the image sensor chip.

Claims

1. A method for fabricating an electronic device package, comprising:

forming a plurality of conductive traces on a surface of a transparent substrate, each conductive trace of the plurality of conductive traces having a first attachment point and a second attachment point;

providing an optically interactive electronic device having at least one bond pad on an active surface thereof;

bonding the at least one bond pad of the optically interactive electronic device to the first attachment point of a conductive trace of the plurality of conductive traces;

providing a backing cap having a base and sidewalls extending transversely from a perimeter of the base and at least one conductive pad on a first surface of the base thereof; and

attaching the backing cap to the transparent substrate to cover a back surface of the optically interactive electronic device and provide electrical communication between the second attachment point of the conductive trace and the at least one conductive pad on the first surface of the backing cap.

2. The method according to claim 1, wherein forming a plurality of conductive traces on a surface of a transparent substrate comprises forming the second attachment points of the plurality of conductive traces in at least one row extending adjacent a perimeter portion of the surface of the transparent substrate.

3. The method according to claim 2, further comprising:

forming the second attachment points of the plurality of conductive traces in multiple rows extending adjacent the perimeter portion of the surface of the transparent substrate.

4. The method according to claim 1, wherein forming a plurality of conductive traces on a surface of a transparent substrate comprises:

disposing a conductive or conductor-filled material onto the surface of the transparent substrate in a pattern defining the plurality of conductive traces.

5. The method according to claim 1, wherein forming a plurality of conductive traces on a surface of a transparent substrate comprises:

disposing a layer of conductive material on the surface of the transparent substrate; and

selectively etching the conductive material to define the plurality of conductive traces.

6. The method according to claim 1, further comprising:

depositing a bead of sealant material on the surface of the transparent substrate along at least one side of the optically interactive electronic device and in contact therewith.

7. The method according to claim 6, wherein the sealant material is selected to comprise one of epoxy and silicone.

8. The method according to claim 1, wherein the optically interactive electronic device is selected to comprise an image sensor.

9. The method according to claim 1, further comprising:

mounting a plurality of optically interactive electronic devices on a single transparent substrate; and

dividing the single transparent substrate to provide individual electronic device packages.

10. The method according to claim 1, wherein attaching the backing cap to the transparent substrate comprises forming a bond between the at least one backing cap conductive pad and the second attachment point of the conductive trace, the bond being selected to comprise one of a conductive or conductor-filled epoxy, a solder joint and a layer of anisotropically conductive adhesive material.

11. The method according to claim 1, further comprising:

forming an array of attachment pads on a second surface of the backing cap.

12. The method according to claim 11, further comprising:

providing a discrete conductive element on at least one attachment pad of the array of attachment pads on the second surface of the backing cap.

13. The method according to claim 12, wherein the discrete conductive element is selected to comprise one of a solder ball, a solder column, a conductive epoxy, and a conductor-filled epoxy.