They can make their own ingots and ultra pure chemicals, and turbopumps and ion implantation machines and spin coaters CVD machines and and the HEPA filters for

They can make their own ingots and ultra pure chemicals, and turbopumps and ion implantation machines and spin coaters CVD machines and and the HEPA filters for the cleanroom, and the remote servers that control the licensing dongle for the robot arm that movies the thingie from "A" to "B"? Sand to "hello world" is a tall order. There is a pyramid of industry that supports the entire thing. Even Sand -> 99.9999 % Si (purification & Czochralski crystal growth) needs multi‑story furnaces, vacuum pulling stations, 10 MW of steady power, and months of process engineering. All of have huge dependency chains. Even modern "mild" events like supply chain disruptions would be enough to shut down any sort of non-toy level production in short order. So yeah, a university as it currently stands can make a microchip, relying on all of these dependency chains being in operational order. But I don't doubt that would quickly no longer be the case if you had a hot war or societal collapse. The exponential growth in processor capabilities relied on a global manufacturing infrastructure from the 1970s until today. To do the same level of progression would require much of that infrastructure. Assuming someone managed to strategically nuke every major foundry / chemical / machine supplier, but leave everything else the same? Sure, maybe we get back to our present tech in 15-20 years. Assume it's the result of a societal collapse? No way in hell.