We didn't have the semiconductor science needed to make effective ICs until we started building them.
The logic is relatively easy, but the materials science needed to decide what to lithograph, using which materials, and in what order, is post-WWII, and probably couldn't have been invented much earlier.
It takes a lot of work to work out ideal doping factors and diffusion rates, estimate charge distributions across junctions, calculate propagation speeds, and eliminate leakage.
But more - the chemistry of semiconductor doping and deposition is often rather nasty, and it would have been a huge challenge to industrialise it before WWII.
well most chips these days are done with FETs which don't really need semiconductors in the way we usually think about them ... and FETs were invented (and largely forgotten) before bipolar transistors ... but doped semiconductors does make it easy to make FETs
The logic is relatively easy, but the materials science needed to decide what to lithograph, using which materials, and in what order, is post-WWII, and probably couldn't have been invented much earlier.
It takes a lot of work to work out ideal doping factors and diffusion rates, estimate charge distributions across junctions, calculate propagation speeds, and eliminate leakage.
But more - the chemistry of semiconductor doping and deposition is often rather nasty, and it would have been a huge challenge to industrialise it before WWII.