SemiAccurate's Charlie Demerjian claims TSMC shut down 28nm production about three weeks ago to make unnamed changes to the process. The site has no explanation as to why TSMC took such a drastic step, but notes that yields didn't seem to be the issue. AMD reportedly still has a lot of 28nm inventory, but if the news is true it could be pretty bad for NVIDIA's Kepler launch.
Sources tell SemiAccurate that the stoppage was quite sudden, and production should resume in short order. One source said that by the end of March, volumes would be back to where they were before if not a lot better. Checks with the channel have confirmed an abrupt stop in 28nm chip shipments, not that there were many to begin with. TSMC is privately promising a quick and planned down time with a resumption in production very soon.
Whether wafers in process were continued, paused, or scrapped is not known. If the parts that were started can be continued on once the switches are flipped back to ‘go’, the production blip won’t be that bad. Because all are saying the whole episode will be but a bad memory by month’s end, we believe that wafers were just paused. If that were not the case, if production restarted today, you would not be seeing new chips coming out until June.
Legit Reviews spoke to AMD and NVIDIA employees about this rumor and reports they could not confirm or deny it.