On Jun 15, 2015, at 15:07 , Noel Chiappa <jnc at
mercury.lcs.mit.edu> wrote:
One wonders why some manufacturer didn't realize there was money to be made
in smaller cards (now less competition, but still enough demand to drive the
prices up) and keep making them.
Because the chip fab equipment that was used to make the dies in the spaller parts has
probably already been retired in favor for equipment suitable for smaller process
geometries, and there's no point in making dies with storage capacity smaller than
what fits in the minimum die size dictated by the pad ring necessary for the I/O. There
actually is a lower limit to memory capacity, beyond which the cost cannot be reduced and
the die cannot be shrunk. We call such chips "pad limited", as in the I/O pads
dictate a minimum die size, and the die will cost almost exactly the same (save for minor
yield variations) whether the middle is filled with gates or not.
I don't think that the hangups of a very few people justify ignoring the economics of
semiconductor manufacturing.
--
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/