Last week we covered a video from Roman ‘der8auer’ Hartung where he started his mission to actually get to the die of a $2,000 USD Intel Core i9 7980XE processor. Don’t worry, he wasn’t attacking a new and functional chip. It was actually a broken one that someone passed on to him with the sole purpose of destroying it in order to retrieve the actual die. He returned yesterday with Part II of the video.
So just to recap. First he delidded the CPU using a specialized Skylake-X version of the Delid-Die Mate tool. He then cleaned up the chip, removing the liquid metal with acetone. Going outside to avoid breathing moxious fumes, Roman then heated the chip up to temperatures beyond 450 degrees Celsius. This allowed him to actually remove the die from the silicon package, an job that proved to be rather difficult due to the underfill layer of the chip which will not budge unless you get it really hot. Eventually Roman plans to do an examination of the die itself using a USB microscope which is capable of 220x zooming and image polarization.
Before that however he wants to remove the copper layer that remains on the chip. To this submerges the chip in 40% iron(III) chloride (or ferric chloride if you prefer) using an ultra sonic cleaner with temperature control functionality. This ensures that the iron (III) chloride is in the correct temperature range. After around two hours, you can see how the copper layer is starting to wear away, revealing some the die structure beneath.
What you end up with after all this work, is the actual die of the CPU can be seen, although you have to zoom in and look at it in the right light. The next step is to use glass etching paste, a similar process to that used above, just more a bit more dangerous. Not surprising as it contains hydrofluoric acid. After ten minutes or so, the CPU die is fully recovered, and looking pretty cool (as in the photo above). It’s fascinating to see the various parts of the CPU actually revealed on the die.
You can watch the video for yourself, here on the der8aeur YouTube Channel.