Chip that come into the museum are all scanned on a Canon 5600F flatbed scanner. It has a good (there is some better though) depth of field, and its fast. Typically chips are scanned at 300dpi, or for small ones (or ones that have a die visible) 600dpi. This keep the file sizes reasonable, yet still allows them to be studied in good detail on CPUShack.com as well our records.
There are on occasion chips that are VERY hard to scan, either the markings are very small, or very shallow. This is becoming common on more modern chips, for one the chips themselves are smaller, and second, they are most often laser marked, and there isn’t enough thickness in the package (or die on some) for the Grand Canyon engraving of the 80’s.
This is a Intel QG80331M500 IO Processor made by Intel in 2007. It is the replacement for the 80960 based I/O processors, using instead a 500 MHz XScale ARM Processor core. This scan was done at 1200 dpi, the part number is visible, barely, but the S-spec and FPO (lot code) are not. The markings are laser etched directly onto the surface of the silicon die. This is fairly common on this type of chip (as well as most all of Intel chipsets). How do we improve upon this? Bumping the resolution to 2400dpi just makes a bigger blurry picture (with more noise). What we need is better resolution, at where the scanner works best (less noise at 1200 dpi scan).
Thankfully we can use a ‘technology’ that is very much similar to how modern processors themselves are now made. Dumping water on the scanner, also known as immersion scanning.