Eli5- How are incredibly small hardware piece built?


Eli5- How are incredibly small hardware piece built?

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The standard method is called photolithography and basically works by selectively removing stuff:

1. Put a layer of your building material on a surface. The goal is now to remove the parts you don’t want with some acid.

2. Put a layer of a special material on top that can resist the acid, but can be destroyed by light or altered in a way such that it isn’t resistant to the acid anymore.

3. Shine a laser on the parts you don’t want to keep – this is the essential step that allows us to create fine structures since we can focus a laser much finer than we can apply some material.

4. Now put the acid onto the whole surface – parts that were touched by the laser light in step 3 are etched away, the others remain.

5. Now remove the coating layer that remains (from step 2) with some chemical that doesn’t attack the building material from step 1.

Then you end up with very fine structures on top of some bulk. You can also repeat this for additional layers (though usually you don’t stack too many since the surface is no longer flat, so precision gets worse.

Now, there are variations of this technique (for example, you might use a material in 3. that becomes resistant to acid after shining light on it and such), but this is the main idea. Of course, it’s not easy at all to get the right amount of stuff, focus the lasers (and move them correctly) and so on. Usually, there’s also an additional chemical step required between 3 and 4 because the laser light only alters the coating layer and you still need to remove it.

It depends on what you mean by “incredibly small” and “hardware”.

If by “hardware” you mean things you might find at a hardware store, then small parts are often made from sheet metal. If this is the kind of “hardware” you are asking about, here are a couple of videos that show how small complicated parts can be made from sheet metal.

This first video does a god job of showing the overall process. I’d call it a small part, but not incredibly small:


This next video shows a smaller part, but it doesn’t show the process. It’s still probably not incredibly small, so maybe this isn’t the kind of “hardware” you are asking about.