Stacked imager package

• US 7,824,961 B2
• Filed: 01/14/2009
• Issued: 11/02/2010
• Est. Priority Date: 09/26/2006
• Status: Active Grant

• Current Assignee: Smartsens Technology (Cayman) Co., Ltd.
• Original Assignee: International Business Machines Corporation
• Inventors: Gambino, Jeffrey P., Rassel, Richard J., Sprogis, Edmund J., Leidy, Robert K., Jaffe, Mark D., Adkisson, James W., Luce, Stephen E.
• Primary Examiner(s): POTTER, ROY KARL
• Application Number:
  US12/353,549
• Publication Number:
  US 20090124047A1
• Time in Patent Office: 657 Days
• Field of Search: 257/E21.532, 438/109, 438/118, 438/106, 438/125, 438/110
• US Class Current: 438/109
• 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 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/16146 the bump connector connecting to a via connection in the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/16227 the bump connector connecting to a bond pad of the item
• CPC Class Codes: H01L 2224/17181 On opposite sides of the body
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2225/06513 Bump or bump-like direct electrical connections between devices, e.g. flip-chip connection, solder bumps
• CPC Class Codes: H01L 2225/06517 Bump or bump-like direct electrical connections from device to substrate
• CPC Class Codes: H01L 2225/06541 Conductive via connections through the device, e.g. vertical interconnects, through silicon via [TSV] manufacturing via connections per se H01L21/76898
• CPC Class Codes: H01L 25/0657 Stacked arrangements of devices
• CPC Class Codes: H01L 27/14618 Containers
• 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 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/15151 the die mounting substrate comprising an aperture, e.g. for underfilling, outgassing, window type wire connections

Abstract

An imaging system for use in a digital camera or cell phone utilizes one chip for logic and one chip for image processing. The chips are interconnected using around-the-edge or through via conductors extending from bond pads on the active surface of the imaging chip to backside metallurgy on the imaging chip. The backside metallurgy of the imaging chip is connected to metallurgy on the active surface of the logic chip using an array of solder bumps in BGA fashion. The interconnection arrangement provides a CSP which matches the space constraints of a cell phone, for example. The arrangement also utilizes minimal wire lengths for reduced noise. Connection of the CSP to a carrier package may be either by conductive through vias or wire bonding. The CSP is such that the imaging chip may readily be mounted across an aperture in the wall of a cell phone, for example, so as to expose the light sensitive pixels on the active surface of said imaging chip to light.

Claims

1. A method of interconnecting chips in a chip package, comprising:

forming backside metallurgy on a first chip;

connecting said backside metallurgy on said first chip to pads on an active surface of said first chip by conductors extending from said backside metallurgy to said pads; and

connecting metallurgy on an active surface of a second chip to said backside metallurgy by an array of interchip solder bumps.

2. The method as set forth in claim 1 wherein said pads on said active surface of said first chip are positioned around the peripheral region of said active surface.

3. The method as set forth in claim 2 wherein said active surface of said first chip includes thereon an array of sensing elements located within said pad positions around said peripheral region of said active surface of said first chip.

4. The method as set forth in claim 3 wherein said conductors are around-the-edge conductors extending conformally around the edge of said first chip to said pads.

5. The method as set forth in claim 3 wherein said conductors are through via conductors extending through said first chip to said pads.

6. The method as set forth in claim 3 wherein said first chip is a sensing chip having said array of sensing elements located within said pad positions around said peripheral region of said active surface of said first chip and said second chip is a logic chip and wherein said sensing chip is mounted across an aperture in the wall of a carrier package so as to expose said sensing elements.

7. The method as set forth in claim 6 wherein said sensing chip and said logic chip are electrically connected to said carrier package by wire bonding.

8. The method as set forth in claim 7 wherein said second chip is a logic chip and the backside of said logic chip is mounted on said carrier package.

9. The method as set forth in claim 8 wherein said logic chip is electrically connected to said carrier package by being wire bonded at one end to pads on said logic chip and at the other end to pads on said carrier package.

10. The method as set forth in claim 8 wherein said logic chip is connected to said carrier package by an array of solder bumps with at least some of said solder bumps of said array of solder bumps connected by through vias to selected one said interchip solder bumps.

11. The method as set forth in claim 10 wherein the planar area of said logic chip is smaller than the planar area of said sensing chip.