Comment by Tuna-Fish
5 days ago
> Except silicon, power, and water (and a tiny amount of plastic/paper for packaging), what else does a fab need that only produces DRAM? If true, then power is far and away the most variable input cost.
Borrowing costs can be wildly variable and are the main cost of making silicon. All the "inputs" over the lifecycle of a fab are so completely dwarfed by the initial capital costs that you can pretty much ignore them in any economic analysis. The cost of making chips is the cost of borrowing money to pay for capital costs, and the depreciation of the value of that capital.
This theory sounds nice, but do you have any sources to share? For example, I assume a fab runs for about 20-30 years. The labor inputs must be very high over this period. Basically, there are no poorly paid people inside a fab. And wouldn't "wildly variable borrowing costs" also affect oil and gas who need to finance the research phase and construction of the plant?
> For example, I assume a fab runs for about 20-30 years.
If only.
20 years ago, fabs were being built to use 90nm class technology. Chips made on such an old node are so cheap today it can't pay even fraction of a percent of the capital costs of the plant per year. So all of it's capital has to have been depreciated a long time ago.
The oldest process node in high-volume production for memory is currently 1α, which started production in January 2021. It is no longer capable of making high-end products and is definitely legacy, and also has to have essentially depreciated all of the capital costs. The time a high-end fab stays high-end and can command premium prices, and during which it has to depreciate all the capital is ~3-5 years. After that either you push the plant to produce legacy/low price and low margin items, or you rebuild it with new tools with costs >$10B.
Also, even if fabs did last 20-30 years, the capital costs would dominate.
> And wouldn't "wildly variable borrowing costs" also affect oil and gas who need to finance the research phase and construction of the plant?
I don't understand? Nothing else costs anywhere near as much capital to produce than silicon chips. Thanks to the inexorable force of Moore's second law, fabs are machines that turn capital investment into salable product, nothing like it has ever existed before.
Micron Fab 6 is about 2300 staff (including 1000 contractors).
Even if you pay them all 500k per year, that's "only" about a billion a year in payroll.
The New York fab plan costs something like 20 billion more or less now to build, with 100 billion over 20 years.
Also, maybe the calculus is different right now in the US, but it used to be the semiconductor workers were expected to have PhDs coming out of their ears but were not actually paid very well, with salaries in Taiwanese fabs being around the $50-60k mark, and lower paid workers being more like $20k or less. Presumably US fabs will be automated to an even greater extent due to labour costs.
So it's very possible that servicing debt on the capital outlay is substantially more expensive than the payroll.