Browse Prior Art Database

Method to Improve Soldering and Replacement of Pin Grid Array Components on Complex Printed Circuit Boards

IP.com Disclosure Number: IPCOM000117505D
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Frech, R: AUTHOR [+4]

Abstract

Disclosed is a method to facilitate the soldering and replacement of pin grid array components. This approach allows lead/tin soldering and replacement of pin grid array components, even for printed circuit boards with at least seven power planes (and at least seven ground planes). The method has no negative impact on the electrical performance of the package and especially does not increase the noise level.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method to Improve Soldering and Replacement of Pin Grid Array Components
on Complex Printed Circuit Boards

      Disclosed is a method to facilitate the soldering and
replacement of pin grid array components.  This approach allows
lead/tin soldering and replacement of pin grid array components, even
for printed circuit boards with at least seven power planes (and at
least seven ground planes).  The method has no negative impact on the
electrical performance of the package and especially does not
increase the noise level.

      The solder process of pin grid array components on complex
printed circuit boards has to deal with two severe problems which
increase with the growing number of power and ground planes in the
board:
  o  insufficient hole fillet of the plated through-holes especially
      for the power/ground holes
  o  increasing thermal stress.

Conventional solutions of these problems are, e.g.:
     power/ground pin connection to alternate planes (1),
      thermal vents in the power and ground planes (1), low melt
      solder (immersion wave soldering with tin/bismuth, (2).

      The replacement of lead/tin solder by tin/bismuth is
presently not always possible, e.g., if the ball or column grid array
technology is used on the same printed circuit board or card.

      In spite of the usage of thermal vents, too much heat escapes
from the power and ground plated through-holes for complex boards
with increasing number of power and ground planes.  This is
significant, especially for the through-holes at the periphery of a
pin grid array component.  The result is insufficient hole fill.
Increasing the board temperature during soldering (or component
replacement) can solve this problem, but this increases the thermal
stress.  In consequence, board delamination or cracking of the plated
through-holes can be caused [2].

      In order to minimize...