Browse Prior Art Database

Ball Grid Array and Column Grid Array Module Solder Paste Fixtures / Handlers

IP.com Disclosure Number: IPCOM000112922D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 88K

Publishing Venue

IBM

Related People

Isaacs, PD: AUTHOR [+3]

Abstract

Disclosed is a Ball Grid Array (BGA) and a Column Grid Array (CGA) module fixture to facilitate solder paste screening with ease of handling.

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This is the abbreviated version, containing approximately 53% of the total text.

Ball Grid Array and Column Grid Array Module Solder Paste Fixtures
/ Handlers

   Fig.  1 displays the following:

A  BGA and CGA module solder paste fixture/handler

B  Module solder stencil template

C  BGA or CGA module cavity

D  BGA or CGA module retainer

E  Module retainer spring

F  Locating holes

G  Material removed for weight reduction

      Disclosed is a Ball Grid Array (BGA) and a Column Grid Array
(CGA) module fixture to facilitate solder paste screening with ease
of handling.

BGA and CGA module solder paste fixtures have the following features:

o   The fixtures utilize the BGA/CGA Module solder stencil template
    with the following advantages:

    -   The template supports the solder paste stencil to prevent
        sagging of the stencil to all for more consistent screening
        of solder paste.

    -   The template thickness supports the stencil in such a way
        that the solder volume that is actually screened correlates
        to the solder volume that would be screened with a much
        thicker stencil without the corresponding problem of plugging
        the stencil openings that are associated with thicker
        stencils.

    -   The thickness of, and the opening in, the stencil and the
        thickness of the template are optimized to provide the proper
        solder paste volume.

    -   The template provides support such that the volume of solder
        paste deposited has a much tighter variance in volume
        distribution and the solder paste deposit is better defined.

    -   The ratio of the template opening and remaining web between
        holes is optimized to adequately support the solder paste
        stencil and small enough not to remove or smear solder paste
        when the module and template are separated.

    -   The template prevents the solder stencil from touching the
        solder balls or solder columns and therefore also prevents
        the stencil from damaging the solder balls or solder columns

       Fig.  2 displays the following:

    A  Module solder stencil template...