Mmmmm mac and cheese! Now I'm hungry.
All good guesses, and graphite is the closest! Fifty trias to Bilbous - but Laragorn gets the second prize of 49 trias for his guess of "crystal".
This is the "backside" of a Silicon wafer after something went "horribly wrong" during an etch process. Made a nice picture though.
*************************
More details?
The goal of this project was to create Si microchannels on the frontside of the wafer.
This is done by taking a Si wafer (polished on both sides) and coating both sides with 2 microns of Silicon Nitride (SiN) and cutting an image of the channels in the SiN. The SiN acts as a hard mask (think stencil) to the etchant.
We then etch the Si to form the channels. This is a timed process, so it just runs for X amount of time and is taken out of the etchant.
What happened here was that there was only 1.2 microns of SiN as a hard mask. So there wasn't enough SiN to protect for the entire time. Once the SiN was gone, the Si surface was exposed to the etchant.
So the "squares" are pin holes in the SiN that have been etching before the majority of the SiN was etched away. This shows the Si crystal lattice. It looks like inverted Pyramids when etched.
The "circles" are formed once the SiN was totally etched away. The etchant is free to attack the Si from all angles.
The "triangular"ish thingy is a hole from the front side of the wafer clear through to the back. A catastrophic failure.
