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ReallyGene t1_jeeox4t wrote

Reply to comment by richiehustle in ELI5: Why computer chips nanometers progress is gradual? Why can not the technology bump up to the lowest nm possible immediately since the concept and mechanisms of it is already known and studied by richiehustle

Because an individual photolithography machine costs millions of dollars to build.

The first prototype usually costs several times that.

To get smaller features, you have to keep using shorter and shorter wavelengths of light.

The latest machines use ultraviolet light. So, in order to see what's happening, you need UV cameras, and software to convert the images to something the human eye can perceive.

Then, you need to develop techniques that can etch those tiny features; it's roughly analogous to writing with a marker; what works when the letters are 4" tall doesn't work when they're 1/8".

You need ultra pure chemicals in an ultra clean environment. But many of those chemicals require special handling and materials to transport and apply them. Those materials in turn require exotic techniques to make and machine them.

So you might have to become the world expert in welding a particular metal, at incredibly small scale, without contaminating anything.

The world is full of failed attempts at all of these things.

You might spend hundreds of millions of dollars just to fail.

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Aggietallboy t1_jefg66v wrote

Please also remember that we're already doing voodoo fuckery where the "x nm process" is already smaller than the wavelength of the light doing the process.

In order to get much smaller, you're no longer talking about "light" but rather other high frequency EM radiation, which, as you're pointing out, we don't necessarily have the technology to

A) reliably generate that EM radiation precisely

or

B) use that frequency of radiation to achieve the equivalent photolithography.

There's also going to be (if there isn't already) a point at which the insulative properties of the silicon substrate aren't sufficient to keep the electrical signal isolated in the circuits.

There's also one more element at play, and that's the size of the element silicon itself:

A silicon atom is 1.92 Angstroms wide.

1 nm = 10 angstroms.

Silicon's "Lattice Constant" - how the atoms are arranged in a crystal is 5.4 angstroms wide (.54 nm)

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