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A Greener Chip Manufacturing Process
gardenermike writes "A new chip manufacturing process has been developed which uses UV light instead of high temperatures to prepare the silicon. This could lead to cheaper chips and greener factories if it pans out. Apparently the main problem is defects in the material, which are currently 'ironed out' as a side-effect of the extreme temperatures used."
Semi-arbitrary. Each whole generation is half the feature size of the generation before, starting from 0.650 micron (650nm). In between are "half" generations counting down from 1000micron.
Half generations: 1000, 500, 250, 130, 65, 32, 16
Whole generations: 650, 350, 180, 90, 45, 22
The precise digits are chosen for convenience and actual processes vary a bit up and down for a given technology node. Each node requires new equipment. By moving from node to node together, manufacturers share some of the cost of development. Still, odd ball nodes do exist. DRAM's are often manufactured at intermediate dimentions and 150nm is used by some foundaries.
Many fabless chip makers will skip half generations. I know a lot of manufacturers went straight from 350 to 180. Still, the choice to skip or not is mostly economic. If a node lands durring a recession, fabless chip makers are likely to hold off until the node that follows. The fabs don't really have a choice. They have to produce each generation in sequence, at least at small scale, or they will not have the technological base to start work on the nodes that follow.
The sizes are governed by 2 factors, the wavelength of the UV light used, currently 193nm, transitioning to the 157nm for the 45nm chips, and the diffraction gratings/refraction of immersion fluid/polarization of said fluid, etc. used. Due to the physics behind this (i wont bore you with the long equations, because i dont want to do them again) there's basically certain points at which these effects add up to the greatest possible resolution/intensity/etc. Any more in depth and i'd have to dig up my lithography text, and i dont really want to :)
drunk chemists
The inter-metal-layer oxide that is begin replaced by low-K dielectrics is/was not formed by oxidation but by chemical vapour deposition. This oxide process is targetted at gate or isolation dielectrics. High-K dielectrics are in the roadmap to replace oxide at the gate dielectric, but development is much slower than people thought 5-6 years ago. In fact, it may never happen before we switch to different materials altogether.