From the article: "Amazon licensed much of the technology from ARM, the company that provides the basic technology for most smartphone chips. It made the chip through TSMC, a Taiwanese company."

Amazon became an ARM architecture licensee and had their variant manufactured for them by TSMC.

I find the characterization "home grown" as a stretch here, had they designed their own instruction set etc I might agree.

That said, the interesting thing about this article is that given Intel's margins, a company like Amazon feels they can take on the huge cost of integrating a CPU, support chips, and related components to achieve $/CPU-OP margins that are better than letting Intel or AMD eat all of that design and validation expense.

This sort of move by Amazon and AMD's move to aggressively price the EPYC server chips, really puts a tremendous amount of pressure on Intel.