An 8k FLASH, 512 bytes EEPROM, 512 bytes SRAM CPU operating 1:1 with the external world unlike those Microchip PIC’s we love to write up about :).
It’s a 350 nanometer (nm), 3 metal layer device fabricated in a CMOS process. It’s beautiful to say the least; We’ve torn it down and thought we’d blog about it!
The process Atmel uses on their .35 micrometer (um) technology is awesome.
Using a little HydroFluoric Acid (HF) and we partially removed the top metal layer (M3). Everything is now clearly visible for our analysis. After delaying earlier above, we can now recognize features that were otherwise hidden such as the Static RAM (SRAM) and the 32 working registers.
As we mentioned earlier, we used the word, “awesome” because check this out- It’s so beautifully layed out that we can etch off just enough of the top metal layer to leave it’s residue so it’s still visible depending on the focal point of the microscope! This is very important.
We removed obscuring metal but can still see where it went (woot!).The two photos above contain two of the 30+ configuration fuses present however it makes a person wonder why did Atmel cover the floating gate of the upper fuse with a plate of metal (remember the microchip article with the plates over the floating gates?)
We highlighted a track per fuse in the above photos. What do you think these red tracks might represent?