People often take it as given that discussions of a move to 450 mm wafers are driven by high-volume low-mix fabs, such as Intel's microprocessor lines or Samsung's memory fabs. Not so fast, says TSMC. DigiTimes reports that the foundry believes larger wafers are essential for its long term growth and productivity improvement as well. (Long term meaning beyond 2012, which TSMC sees as the target for 450 mm pilot production.)
The arguments in favor of a bifurcation between high volume and high mix fab designs do have merit. On the other hand, a shift as big as a wafer size transition requires lots of resources from all along the supply chain. There are advantages to getting the whole industry on board the same train, too.