Samsung was able to smoothly transition from 90-nm to 80-nm process technology because it utilized many of the basic features of 90-nm geometries, and as a result required minimal upgrades to its fabrication lines.
The move to 80-nm circuitry was sped up by the use of a recess channel array transistor (RCAT). This three-dimensional transistor layout greatly enhances the refresh rate, which is a critical element in data storage. Samsung's RCAT also reduces cell area coverage, which allows for increased process scaling by freeing up space for chip-per-wafer growth.
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