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Antenna Diodes in the Pentium Processor

righto.com

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Re: Antenna Diodes in the Pentium Processor

#35
post #2

Author here: I know this is a very obscure topic, but hopefully it will be interesting to some. Let me know if there are any questions...

Late to the show, but this only works because the deposited charge always has the same sign, correct? For instance, if the ions used are positive icons (electrons stripped), the surface elements get positively charged, and the diodes drain that charge to the substrate. But, in operation, the surface elements are negatively charged, so the diodes block. (Right? Or is it the other way around?)

Re: Antenna Diodes in the Pentium Processor

#37

Do we have the technology to automate reading of decapped chips so that we can reconstruct the logic, something like "OCR"? It seems like such a thing would be hard if it has to deal with all these weird details.

It exists, though I don't know of any free or open versions

Re: Antenna Diodes in the Pentium Processor

#38
post #2

Author here: I know this is a very obscure topic, but hopefully it will be interesting to some. Let me know if there are any questions...

Late to the show, but this only works because the deposited charge always has the same sign, correct? For instance, if the ions used are positive icons (electrons stripped), the surface elements get positively charged, and the diodes drain that charge to the substrate. But, in operation, the surface elements are negatively charged, so the diodes block. (Right? Or is it the other way around?)

The diodes break down nondestructively under the voltage, getting rid of the charge regardless of polarity. During operation of the chip, the diodes are reverse biased, so they have no effect.

Re: Antenna Diodes in the Pentium Processor

#39
post #2

Author here: I know this is a very obscure topic, but hopefully it will be interesting to some. Let me know if there are any questions...

Great article! > Note that when the chip is completed, every transistor gate is connected to another transistor's source or drain (which provides the signal to the gate) That's a very curious assertion, which made me think a bit more (it feels incorrect at first but on a second thought it looks correct) I would think of "pure input pins" but I suppose those have pull-up or pull-down "resistors" which in silicon are a…

Yes, input pins are kind of an exception; the source or drain providing the voltage is external.

Re: Antenna Diodes in the Pentium Processor

#40
post #34
post #2

Author here: I know this is a very obscure topic, but hopefully it will be interesting to some. Let me know if there are any questions...

This is amazing! How did you get the pictures?

I spent a long time with various chemical processes to remove the layers of the chip before discovering that 1500-grit sandpaper works shockingly well. Then I took the pictures with my metallurgical microscope and stitched the images together with a program called Hugin. I wrote a blog post about the process: https://www.righto.com/2015/12/creating-high-resolution-inte...
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