There was a company in Worcester Ma. that made IC chips, it was Sprague Electric.
They made custom chips for assorted customers, and did it by the 10s of thousands.
A friend was chief engineer for them, got to tour the plant several times, day and night.
The best part was that I got to use their fabulous lab at night for calibrating some of my ham equipment.
They had the top of the line of everything in test equipment, even computers, I would drool over it all.
They had copy cameras that would have been quality enough for spy satellite use,
they were for making the mask.
Jim told me the camera lenses IIRC were 30-40 thousand each, made by American Optical.
Camera assemblies were mounted on concrete bases 10 feet deep in the ground,
and had anti-vibration units under the cameras.
It was a clean room, I could not go in there without a half hour of showers and vacuuming,
it looked much like a bio lab and so did much of the production floor.
They, my guessing, reduced a drawing from about 4X5 feet down to a quarter of an inch.
Originally in the early 1900s they made all sorts of capacitors, and did right up into the 60s.
About 1975 they were gone, operations moved elsewhere,
my friend did not go with them wherever they went.