Control of size and heat affected zone for fine pitch wire bonding

• US 6,180,891 B1
• Filed: 02/26/1997
• Issued: 01/30/2001
• Est. Priority Date: 02/26/1997
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Murdeshwar, Nikhil M.
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): Cuneo, Kamand
• Application Number:
  US08/806,818
• Time in Patent Office: 1,434 Days
• Field of Search: 174/260, 174/250, 228/180.5, 228/110.1, 361/767, 361/772, 361/773, 361/776, 257/693, 257/780, 257/784, 438/617
• US Class Current: 174/260
• CPC Class Codes: B23K 20/005 Capillary welding
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• 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 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/4851 Morphology of the connecting portion, e.g. grain size distribution
• CPC Class Codes: H01L 2224/48511 Heat affected zone [HAZ]
• CPC Class Codes: H01L 2224/48644 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48699 Principal constituent of the connecting portion of the wire connector being Aluminium (Al)
• CPC Class Codes: H01L 2224/48744 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48844 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/78302 Shape
• CPC Class Codes: H01L 2224/78313 Wedge
• CPC Class Codes: H01L 2224/85045 using a corona discharge, e.g. electronic flame off [EFO]
• CPC Class Codes: H01L 2224/85075 : being inert
• CPC Class Codes: H01L 2224/85181 : connecting first on the semiconductor or solid-state body, i.e. on-chip, regular stitch
• CPC Class Codes: H01L 2224/85205 : Ultrasonic bonding
• CPC Class Codes: H01L 2224/92247 : the second connecting process involving a wire connector
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/78 : Apparatus for connecting with wire connectors
• CPC Class Codes: H01L 24/85 : using a wire connector wire bonding in general B23K20/004
• 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 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01007 : Nitrogen [N]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01018 : Argon [Ar]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/20752 : larger or equal to 20 microns less than 30 microns
• CPC Class Codes: H01L 2924/20753 : larger or equal to 30 microns less than 40 microns

Abstract

The amount of melting of the bonding wire is closely regulated, and reduction of size and improvement of uniformity of the free air ball is obtained for ball bonding at pitches of less than ninety mils even when bonding wire of reduced diameter is employed. Quenching of the bonding wire adjacent to the free air ball also limits the temperature rise in the bonding wire and the extent of a heat affected zone having less tensile strength and stiffness to less than one micron and with reduced grain enlargement. The present invention provides such a bond for electronic packaging of increased reliability, potential functionality, increased manufacturing yield and reduced process complexity.

Claims

1. A product including

a first surface,

a second surface,

a first bonding wire having a first end bonded to a first portion of said first surface by a ball bond and a second end bonded to a first portion of said second surface,

a second bonding wire having a first end bonded to a second portion of said first surface by a ball bond and a second end bonded to a second portion of said second surface, wherein the pitch between said ball bond on said first bonding wire and said ball bond on said second bonding wire on respective ones of said first and second portions of said first surface is less than 90 microns and volume of free air balls forming said ball bonds is substantially uniform.

2. A product as recited in claim 1, wherein said product is an electronic circuit package,

said first and second portions of said first surface are bonding pads on a chip, and

said first and second portions of said second surface are bonding pads on a chip carrier.

3. An electronic circuit package as recited in claim 2, wherein annealing associated with said ball bonds is confined to a thickness of less than one micron.

4. An electronic circuit package as recited in claim 2 wherein said bonding wires are of a diameter of less than one mil.