Season's Greetings to All
 Could some one please cast some light for me on the following
 contrasting information regarding the pad size for pbga and microbga:
 Quoting from IPC-7095 Design and Assembly Process Implementation
   for BGA ( May 1999  Proposal Issue): On Para. 6.2 Attachment Sites
 "6.2.1 Big Vs Small Land and impact on routing:
          The diameter of the solder land can affect both the reliability of
the solder
           joint and also the routing of conductors. Several studies have
          shown that large solder land  (up to 0.8 mm in diameter ) increase

          the fatigue life of PBGA packages. However the larger the lands,
          the less room for routing between lands."
   On the other  hand , quoting from an application note published by Amkor:


http://www.amkor.com/customer_center/assembly_and_test/white_papers/appnotes
_0800.pdf
   on page 13 : "'life increases by up to 20% for smaller PCB pads"
   Which makes sense from the point of getting a higher standoff.
 Obviously both sources refer to the issue, when one has the option,
 which is limited anyhow , in which way to go,
 whether to increase or decrease  the pad size .

 Mickey
 ECI Telecom