An chip plant's real cost isn't concrete. It's the machines nobody budgets for

Chip factories have grown into some of the priciest buildings ever constructed. Machines packed inside actually cost more than the walls around them

Daniel Ceng / Anadolu via Getty Images

Companies keep announcing chip plants that cost billions, and every number sounds equally enormous. Most of that money isn't going into the building. It's going into the machines inside it, and that's the part of the bill that actually separates one announcement from another.

The machines account for 70% to 80% of a modern chip plant's total cost, according to an analysis by Construction Physics. A single facility can run $10 billion to $20 billion or more, and most of that money goes to machines, not concrete and steel. Elon Musk has proposed a $119 billion semiconductor complex in Texas, and machines would likely account for most of that price, too.

That escalation follows a predictable curve. A facility that cost about $4 million in the early 1970s grew to roughly $14 billion by 2015, doubling every four years or so under what the industry calls Rock's Law. TSMC $TSM has committed $165 billion to its Arizona campus, spread across six plants, two packaging facilities, and a research center, matching the scale Rock's Law would predict for today.

The machines that cost more than the factory shell

Samsung has committed at least $17 billion to its........

© Quartz