How to Reverse Engineer a Chip

Have you ever wondered how you could look at a chip and map out its schematic? [Robert Baruch] wants to show you how he does it and he does in a new video (see below).  The video assumes you know how to expose the die because he’s made a video about that before.

This video focuses on using his Beaglebone-driven microscope stage to get high-resolution micrographs stitched together from smaller shots. A 3D-printed sample holder keeps the part from moving around. Luckily, there’s software to stitch the images together. Once he has the die photo, he will etch away the metal to remove the passivation, the metal layer, and the silicon dioxide under the metal and takes another set of photos.

[Robert] loads the images into Inkscape so he can trace over the various components of the device and add labels. Then he uses KiCAD to produce the schematic. The end result is an entry on the Project 54/74 wiki. The project we’ve mentioned before that aims to document this historically significant family of ICs.

If you want to duplicate his efforts, be warned that you need some fairly nasty chemicals, so be careful. Real labs use hydrofluoric acid to etch glass, which is especially nasty. [Robert] uses Armour Etch, which is slower but a bit safer and easy to get and store.

A 74LS01–the subject of the video–only has 8 transistors. Imagine trying to do even a simple CPU like an 8008 with about 3,500 smaller transistors. We recommend coffee and patience.

Filed under: classic hacks