A 300mm wafer is 12 inches in diameter. When using a chip that is 1 square centimeter, a 300mm wafer includes approximately 706 chips. The 300mm wafer has 2.25 times the wafer area than a 200mm wafer or 8 inches, a higher clean room utilization efficiency, and a reduced defect density that will lower die cost. It's also much cheaper to manufacture.
TERMS OF MEASUREMENT:
Micron: A micron is a metric unit of linear measure, which equals one-millionth of a meter. The diameter of a human hair is about 100 microns. Today's semiconductors have line etched at 0.048 microns.
Nanometer: A nanometer is a metric unit of linear measure, which equals one-billionth of a meter. The semiconductor industry is now using nanometer as opposed to "microns" because the conversion is easier as it eliminates the need for decimals. For example, .13 microns is equal to 130 nanometers.