Browse Prior Art Database

Surface Mount Micro-Screener

IP.com Disclosure Number: IPCOM000114121D
Original Publication Date: 1994-Nov-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 85K

Publishing Venue

IBM

Related People

Huston, GA: AUTHOR [+4]

Abstract

Disclosed is a surface mount micro-screener that easily screens local areas with solder paste, solder cream, or a conductive epoxy for local area attach or rework of surface mount components, e.g., Ball Grid Array (BGA), Column Grid Array (CGA), Flip Chip Attach (FCA), Straddle Mount Connectors, Quad Flat Package (QFPs), etc.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Surface Mount Micro-Screener

      Disclosed is a surface mount micro-screener that easily screens
local areas with solder paste, solder cream, or a conductive epoxy
for local area attach or rework of surface mount components, e.g.,
Ball Grid Array (BGA), Column Grid Array (CGA), Flip Chip Attach
(FCA), Straddle Mount Connectors, Quad Flat Package (QFPs), etc.

      A "micro-screener" was designed and built that easily allows
the application of solder paste to a local site or area regardless of
whether there are adjacent components to the area that requires
solder paste.  This technique extends to FCA attach or rework.  For
straddle mount connectors a controlled volume of solder paste can be
locally placed for attach or rework.

      Using this approach, solder paste could be placed on a site.
The module could be placed "into" the solder paste and then mass
reflowed.
 Identifier Description for Figs. 1, 2, 3, and 4.
 Identifier Description
 A    Stencil openings for BGA, CGA, FCA QFPs, Straddle Mount
       Connectors, etc.
 B    Stiffener/Handle
 C    Stencil
 D    Micro-screener stiffener/handle
 E    Squeegee
 F    Solder paste, solder cream, conductive epoxy, conductive medium
 G    Printed circuit board or appropriate substrate.
 H    Non-skid medium, eg.  double sided tape, rubber tape, etc.

Site preparation for module attach process:
 1.  Optional:  On a clean card place a mask or Polyimide tape on
      three sides of the site to act as a dust pan for any extra
solder
      paste.
 2.  Place double stick tape adjacent to one side of the area to be
      screened on the side where the heel of the screener will be
      placed.
 3.  Align micro-screener over the pads either visually or with
      optical or video aids.
 4.  Set the heel of the micro-screener into the double sticky tape.
 5.  Place a bead of solder paste, or...