The reason is to prevent ball collapse which maintains BGA standoff height
for improved thermal cycling reliability.

Regards,
Bruce Misner

-----Original Message-----
From: Lum Wee Mei [mailto:[log in to unmask]]
Sent: Thursday, June 05, 2003 3:36 AM
To: [log in to unmask]
Subject: [TN] BGA substrate pad


Hello,

Just wonder anyone can provide the reason or how the pad on the BGA
substrate
is between 75 - 80% of the ball size?

Regards,
Wee Mei

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