I am referring to the 10nm, 7nm and 5nm manufacturing processes used by Intel and TSMC, where TSMC is offering 5nm what ever that means.
I don’t understand semiconductor manufacturing, however searching and reading through some pages, it seems to indicate the chip density. I would love to understand what that means.
Also, why does it matter iff we are able to pack more chips into a small area? The CPU and chips are already quite small, so I cannot imagine a smart phone benefitting from it. Also doesn’t more chips in a smaller area mean more heat dissipation?
In: Engineering
The smaller the number, the smaller the transistor (the basic unit of which computers are made). The smaller the transistor, the more you can pack into a given area, and thus the more computing power.
Also smaller transistors, which are basically switches in this context, can flip faster and with less power, meaning less heat per computation and higher clock speeds.
Lastly, smaller transistors mean a smaller circuit. Smaller circuits mean less wait time for signals to travel between transistors and yet higher speeds.
Win/win/win, that’s why the number is so important.
The nm rating refers to the width of the gate of a transistor:
[https://www.gaussianwaves.com/gaussianwaves/wp-content/uploads/2016/03/Ntype-MOSFET-width-length-dimensions.png](https://www.gaussianwaves.com/gaussianwaves/wp-content/uploads/2016/03/Ntype-MOSFET-width-length-dimensions.png)
Smaller transistors can run faster, with less power, and (should) cost less to produce. For something like a laptop, you run the smaller chips at the same speed as before to get power savings. For performance, you run the smaller chip at a higher clock. Plus the manufacturer is happy because they get more chips per silicon wafer.
Total transistor count is a separate subject. You can do things like make quad core cpus which vastly increases transistor count, but using the same size transistors.
> Also doesn’t more chips in a smaller area mean more heat dissipation?
Not until recently-ish.
There’s an observation called [Dennard Scaling](https://en.wikipedia.org/wiki/Dennard_scaling). In short, it says that a given _area_ of transistors (i.e. 2mm^2 ) will use the same amount of power, and thus dissipate the same amount of heat, regardless of the size of the transistors contained within.
Sadly, the observation started to break down around 2006, so nowadays we are running into significantly more issues with thermal dissipation.
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