[kuschku]

In the case of 3D arrangements, you don't necessarily need to create all the layers photolithographically. You might be able to flatten N layers into 1 layer, then add a plastic coating equivalent to N-1 layers ontop, then repeat that. You'll have a very similar result to every layer being separate.

Imagine e.g. the "multiple layers of cardboard cutouts" scenery in theater vs it actually being 3D.