4 ms·

You can only ever reach exposed surfaces. This means a very complex sequence of adding and removing layers to expose/hide things so that the currently exposed

• metadat 4y ago
  Wow, that's a remarkably informative image, thank you @ThrowawayR2.
  • tux1968 4y ago
    Steps 7, and especially 8, seem like magic without a good explanation of how they're possible.
    • bippingchip 4y ago
      That’s because they skip quite a few steps. You would first deposit a photosensitive layer, then expose it wit a pattern of light, which will allow you to selectively open up the parts you want to toch next. For step 7 for example, you create a masking layer that way, after which you etch away only the exposed parts where source and drain contacts will end up. For step 8, you do something similar. The openings you’ve etched in step 8 will allow only to dope the contacts, but you need to mask the nmos and pmos separately, otherwise you get the same doping in both transistors. A lot of the ‘magic’ to make this work is in the materials and chemistry: you need selectivity: etching that only interacts with the exposed parts. In highly scaled finfet nodes, the material combinations are very complex as you sometimes want 2, or 3 different material combinations to interact in the way you want, reliably, at nanometer scale. (Edit finfet not finger)