How is the shifting of CMOS nodes done and how is the node number calculated?

We have seen that the CMOS process is shifting from higher nodes to lower nodes such as 130nm to 90nm and 90nm to 65 nm etc. How is the shifting of nodes done and hows the node number calculated?

Why do we have to shift from 90-nm to 65nm and whynot say 75nm.

Thanks,
Vivek

Any idea?

It's up to stardard process, I think.

Any idea?

mainly improvement in equipment (lithography) plus solving some technical issues like doping concentration , gate leakage and substrate leakage and MOSfet engineering and tons of other stuff
y not 75nm well y not 74nm , if they have said any number , it would be questionable , but mainly i THINK this depends on the effectiveness of the reduction like from 90nm to 89nm it is not worth it as u will to do tons of R&D work plus pay tons of dollars on new equipment to get a nearly not that much performance difference so u have to do a market survey and see what will make u gain money , like some Fabs are still not going for lower nodes (AMS for instance) because they are satisfied with their own technology and have their paying custmers for this technology and of course their market study is not advising to go any lower (NOW), but someone like intel if they don't enhance their technology then they are done and to keep their performance slope they have to push their technology to the limit

Any idea?

this is what esearch can give max at the given time

and is it worth to develop

Re: Any idea?

The law of Moore is actually an economic law foreseeing how technological changes will help to go in more dense circuits in bigger wafers. Smaller means cheaper and mass production.

Re: Any idea?

Thanks all for the inputs. It does give me some idea but not very convincing. Even i am trying to find out. i will update if get some solid answers. Thanks once again.
Do add if you come across any interesting answers

Thanks,
Ukint

Any idea?

I think most of this stuff is agreed upon by the International Roadmap - they lay out a plan based upon predictions of how fast the technology will scale. Everybody tries to match or do better than the roadmap to stay competitive.