A structure for a system of chip packages includes a master substrate and
at least one subset substrate of the master substrate. The subset
substrate includes a portion of the master substrate that has an
identical pin out pattern as the portion of the master substrate. The
subset substrate has identical internal net lists as the portion of the
master substrate. The subset substrate is adapted to accommodate a
smaller chip than the master substrate. The master substrate is the
largest substrate in the system. The invention also prepares a system of
chip packages. The invention selects a master substrate and then selects
a subset substrate of the master substrate.