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Antenna Diodes in the Pentium Processor

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Re: Antenna Diodes in the Pentium Processor

#21

Post by accrual »

beenBoutIT wrote: post #14
iakov wrote: post #12

Earlier quoted context omitted.

Your pictures give insight into such a small world, individual freaking transistors on a CPU chip! Reading textbooks and wiki is one thing, but seeing silicon spliced up and photographed up close is another. Very interesting read, and very well presented too, thank you.

It'd be interesting to see how big a CPU chip scaled up to be big enough for a human to fit in (were it hollowed out) would end up being.

Reminds me of the Monster 6502. Not quite what you're suggesting, but still a large discrete monster of a board.

https://monster6502.com/

Instead of a hedge maze maybe we can have VR "walking through a 8086 or 8088" chip style maze in the future.

Re: Antenna Diodes in the Pentium Processor

#22

Post by kens »

accrual wrote: post #15

Very cool that this would be on the front page after I picked up a Pentium-75 from my local recycler today, it's an SX969. I can hold this chip in my hand and look up to see Ken's die shots. So cool! The ceramic package these Pentiums came in are pretty unique as well - it kind of sounds like setting a piece of glass down when I set the CPU on my desk.

That Pentium is the 80502, so it's almost the same as the one in my article except that it is built with 600 nm technology instead of 800 nm and it has 200,000 more transistors. It's easy to knock the lid off the package with a chisel if you want to see the die inside.

Re: Antenna Diodes in the Pentium Processor

#23

Post by araes »

kens wrote: 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...

Reading through, appears this is mostly a manufacturing concern that goes away once the chip is actually active. Correct? The charge buildup goes away, and then there's no further need for the diode antenna.

However, second question, does any chip actually use these for anything afterward? Or are these ever built so they actually do something other than simple provide manufacturing protection?

Example, they build up charge. So then the charge build up itself is effectively used as some form of remote communication method or channel between various portions of the chip. The diode discharges and in discharging effectively acts as some form of communication transfer.

Others, or it serves multiple purposes. One during manufacturing, one after manufacturing? Safety mechanism during manufacturing, and then the charge buildup location is oscillated, purposely charged, or used as a charge outlet for some other reason?

Others, Light Emitting Diode is, kind of by the name, a diode. Any of these that basically do blinking communication or something similar? Emits light when the charge breaks down, then that is picked up and used as data transfer?

Others, not going into extensively. Tune radio and TV receivers (varactor diodes). Generate radio-frequency oscillations (like actual antennas) (tunnel diodes, Gunn diodes, IMPATT diodes).

Basically, anything other than a safety mechanism for manufacturing?

Re: Antenna Diodes in the Pentium Processor

#24

Post by nine_k »

While the discussion of IC architecture is doubtlessly interesting, I want to praise this page, and other pages on that site, for the photos of the circuits. Not only they are enlightening, they also have really great, soothing color palettes.

Re: Antenna Diodes in the Pentium Processor

#25

Post by [deleted] »

kens wrote: post #5
rietta wrote: post #3

Are the antenna diodes only there to reduce damage during manufacture or is there also impact runtime in an electromagnetic noisy environment?

The antenna diodes are only relevant during manufacturing, when a metal line is connected on one end but not the other. ESD diodes on the other hand protect inputs against electrostatic discharge when the chip is in use.

[deleted]

Re: Antenna Diodes in the Pentium Processor

#26

Post by [deleted] »

araes wrote: post #23
kens wrote: 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...

Reading through, appears this is mostly a manufacturing concern that goes away once the chip is actually active. Correct? The charge buildup goes away, and then there's no further need for the diode antenna. However, second question, does any chip actually use these for anything afterward? Or are these ever built so they actually do something other than simple provide manufacturing protection? Example, they build up…

[deleted]

Re: Antenna Diodes in the Pentium Processor

#27

Post by aphantastic »

emmelaich wrote: post #17
danecek099 wrote: post #16

I'm fascinated by the fact that we study this 31 year old technology and are amazed by the complexity

Indeed! A thought experiment I have some times is to imagine that every machine on the earth was destroyed overnight. We still have mines, people, books. How long would it take to get back to the level of industrialisation and science that would allow us to make (in this case) a 3 million transistor chip? The vast majority of people have little idea of how much intellectual effort has gone into the current state of t…

Indeed. A lady at a bar in Portland once inquired what I thought humanity’s most advanced technological achievement was, after a slight pause I said the modern microprocessor. She laughed in my face at the suggestion. But when I pressed her for an answer of her own, she refueled to say, instead would only insist that my answer was ridiculous. Odd lady.

Re: Antenna Diodes in the Pentium Processor

#28

Post by II2II »

emmelaich wrote: post #17
danecek099 wrote: post #16

I'm fascinated by the fact that we study this 31 year old technology and are amazed by the complexity

Indeed! A thought experiment I have some times is to imagine that every machine on the earth was destroyed overnight. We still have mines, people, books. How long would it take to get back to the level of industrialisation and science that would allow us to make (in this case) a 3 million transistor chip? The vast majority of people have little idea of how much intellectual effort has gone into the current state of t…

Perhaps decades. Perhaps thousands of years. It probably depends upon why those machines were destroyed. Look at World War II. European nations and Japan rebuilt relatively rapidly then rapidly built upon progress made during the war. On the other hand, we have the decline of the Roman Empire. While we may now acknowledge that the dark ages weren't as dark as our 19th century peers thought, the western world lost the will or the imagination to rebuild at large scales (which the semiconductor industry certainly is).

Re: Antenna Diodes in the Pentium Processor

#29

Post by kayson »

araes wrote: post #23
kens wrote: 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...

Reading through, appears this is mostly a manufacturing concern that goes away once the chip is actually active. Correct? The charge buildup goes away, and then there's no further need for the diode antenna. However, second question, does any chip actually use these for anything afterward? Or are these ever built so they actually do something other than simple provide manufacturing protection? Example, they build up…

You're correct that these are for manufacturing only. I've never heard of them being used for actual design purposes and that's probably because if you wanted an actual diode, you'd just use a "real" one.

Re: Antenna Diodes in the Pentium Processor

#30

Post by raverbashing »

kens wrote: 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 actually diodes? gateless fets?

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