Micro-fluidic injection molded solder (IMS)

• US 8,162,200 B2
• Filed: 06/09/2011
• Issued: 04/24/2012
• Est. Priority Date: 03/06/2009
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Buchwalter, Stephen L., Gruber, Peter A., Lauro, Paul A., Nah, Jae-Woong
• Primary Examiner(s): Ward, Jessica L
• Assistant Examiner(s): Patel, Devang R
• Application Number:
  US13/156,736
• Publication Number:
  US 20110233262A1
• Time in Patent Office: 320 Days
• Field of Search: 228/33, 228/256, 228/180.21, 228/180.22, 264/145, 264/152, 156/256, 294/28, 222/251, 222/288, 222/564, 222/591
• US Class Current: 228/33
• CPC Class Codes: B23K 2101/42 Printed circuits
• CPC Class Codes: B23K 3/0638 for viscous material feeding, e.g. solder paste feeding B23K3/0623 takes precedence
• CPC Class Codes: B23K 3/08 Auxiliary devices therefor cleaning pipes or tubes or systems of pipes or tubes, e.g. before soldering, B08B9/02
• CPC Class Codes: H01L 21/4853 Connection or disconnection of other leads to or from a metallisation, e.g. pins, wires, bumps
• CPC Class Codes: H01L 2224/0554 External layer
• CPC Class Codes: H01L 2224/0555 Shape
• CPC Class Codes: H01L 2224/0556 Disposition
• CPC Class Codes: H01L 2224/0557 the external layer being disposed on a via connection of the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/05571 the external layer being disposed in a recess of the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05647 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05655 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 24/11 Manufacturing methods for bumps on insulating substrates H01L21/4853
• 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/01006 Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01023 : Vanadium [V]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01042 : Molybdenum [Mo]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01087 : Francium [Fr]
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H05K 1/111 : Pads for surface mounting, e.g. lay-out
• CPC Class Codes: H05K 2201/09472 : Recessed pad for surface mounting recess in pad H05K2201/09745; Recessed electrode of component
• CPC Class Codes: H05K 2203/0126 : Dispenser, e.g. for solder paste, for supplying conductive paste for screen printing or for filling holes
• CPC Class Codes: H05K 3/3457 : Solder materials or compositions; Methods of application thereof
• CPC Class Codes: Y10T 156/1062 : Prior to assembly
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

A portion of compliant material includes four walls defining a slot. The slot has a relatively large cross-section end in fluid communication with a solder reservoir, and also has a relatively small cross-section end opposed to the relatively large cross-section end. The slot has a generally elongate rectangular shape when viewed in plan, with a length perpendicular to a scan direction, a width, parallel to the scan direction, associated with the relatively large cross section end, and a width, parallel to the scan direction, associated with the relatively small cross section end. The slot is configured in the portion of compliant material such that the relatively small cross-section end of the slot normally remains substantially closed, but locally opens sufficiently to dispense solder from the reservoir when under fluid pressure and locally unsupported by a workpiece. Methods of operation and fabrication are also disclosed.

Claims

1. A method comprising the steps of:

providing a sheet of elastomeric material;

cutting a first incision along a surface of said material to form a first straight wall making an angle, α

, with horizontal, said first incision describing a line along said surface of said sheet;

cutting a second incision along said surface of said material to form a second straight wall making an angle, β

, with horizontal, said second incision beginning at said line along said surface of said sheet, such that a slot is formed, said slot having a relatively large cross-section end that gradually narrows to a relatively small cross-section end opposed to said relatively large cross-section end, said relatively small cross-section end being located at said line along said surface of said sheet; and

securing said sheet to a solder reservoir such that said relatively large cross-section end is in fluid communication with a bottom surface of said solder reservoir.

2. The method of claim 1, wherein α

=β

, such that said slot is V-shaped when viewed in cross-section along a length perpendicular to a scan direction.

3. The method of claim 2, wherein α

and β

each range from about 30 degrees to about 70 degrees.

4. The method of claim 2, wherein α

and β

each range from about 45 degrees to about 60 degrees.

5. The method of claim 1, wherein α

is about 90 degrees and β

ranges from about 30 degrees to about 70 degrees.

6. The method of claim 5, wherein β

is about 45 degrees.

7. The method of claim 1, wherein said relatively small cross-section end of said slot, when locally open under said fluid pressure, has a width parallel to a scan direction of from about 2 microns to about 10 microns.

8. The method of claim 1, wherein said first and second straight walls have a length of from about 1 inch to about 12 inches.