Devices (memory, cpus, video chips, etc) get more complex all the time, which means more transistors, which means bigger. The bigger the chips, the more important it is to use a large wafer in order to avoid waste. Wafers are round, and chips are square, so there is always a certain amount of waste, but the larger the chips is relative to the wafer, the more the waste. Plus there are handling considerations as well.
Where line widths /feature sizes fit in is that by reducing sizes you can make the chips smaller, which reduces the problems listed above. Thus to a certain extent by going to smaller feature sizes you can reduce the need for going to larger wafers.
None of this is related to the need for photomasks, only to improving yields of chips.
Carl |
