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Comment by comex | Hacker News Reader

Can you be more specific about what the difference is?

With photolithography, what most chips are made with, the resist is developed by exposing it to UV light. A mask is used so that the desired parts of the resist are left behind, and the rest is washed away. Contact photolithography places the mask directly against the silicon wafer because it helps the optics during exposure, but the mask doesn't directly remove the resist.

In nanoimprint lithograhy, a stamp is pressed into the resist on wafer and leaves the desired pattern behind.

The difference is that the resist is removed mechanically instead of chemically.

How does the stamp not get damaged or degrade over time? Or is this part a consumable / easily replaced?

It might help you to look up https://en.wikipedia.org/wiki/Mimeograph and possibly other copying techniques. More approachable examples include CD / DVD https://en.wikipedia.org/wiki/Compact_disc_manufacturing or earlier vinyl record production methods.

For the case of chip lithography they'd probably make source masks, copy the first generation a time or two, and use those secondary source masks to produce consumable 'stamps' for production.

Hopefully the stamps maintain sufficient quality across at least a couple batches (50-100+?) of wafers.

I highly doubt it will be that much initially. Silicon is pretty hard.

The stamp doesn't touch the silicon or any other solid material, it hovers just above.

It only touches a liquid photo-resist that is spread on the wafer. The stamp is transparent, which allows UV light to shine though and exposes the photo-resist, which solidifies into a mask matching the stamp.

Ah ok! I thought the two were actually in contact. Ok, in that case they might get some life out of them.

It's how cheap holograms are made. They are simply stamped into the material rather than that there is a photographic step during mass manufacturing.

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