Several years ago there was some development of 450mm wafers back when 193nm was state of the art. Today there is a trend to making larger and larger devices on existing lines which would favor the larger wafer. 300mm lines are now the main high production format with factories cranking out upwards of 100,000 wafers per month.
Some devices make on 300mm lines barely have 100 units produced per wafer. A larger 450mm wafer can increase production of larger sized devices. Silicon can be made in large enough sized blocks for 450mm easily.
Semiconductor logic is a huge part of the global economy. It is estimated to be growing at 4% annually and at $90 billion the outlook for the industry is great.
While 450mm wafers have to be slightly thicker which reduces the number of wafers from a given silicon ingot, the advantages outweigh the disadvantages.
It seems that existing 300mm wafers are holding with new foundries over the last decade. It suggests that 450mm does not justify the development in a $12 billion factory. The advantage over time with 450mm is lower unit cost for devices.
Regardless of false claims of feature size, the industry is all crowded around 55 million transistor per square millimeter. The density per square millimeter is a more reliable measure of progress with design and engineering. One barrier is how thin a MOSFET gate can be which was known as far back as 1959 when the MOSFET was first developed with the goal of higher frequency radios.
Organic semiconductor research has been developing over the last several years. Growing Demand for Biodegradable and Low-Cost Semiconductors are the leading motivators