Thanks for posting this. Many of these lenses date back to the days when chips were taped out by hand and had thousands of transistors if that many. Exacto knives and rubylith was all it took. Layers were pin registered on a big light table.
Our latest chip has 21 billion transistors on it. Dozens of mask layers. The very newest silicon processes use 13nm extreme UV light and mirrors, not lenses. Some sort of black magic is involved I think as it would otherwise be impossible!
