Foundry is the fancy semiconductor word for factory. You have to admit, silicon foundry does sound cool.
Another term used for this is a ‘fabrication plant’ or ‘fab’. All chips come from fabs, but when a fab is used to produce ASICs for other companies (ie the company that owns the fab is not the one that designed the chip) then it is typically referred to as a foundry. SkyWater, TSMC, Global Foundries are foundries that produce chips for many different ASIC design houses.
From SkyWater’s website
The SkyWater facility was originally established by Minnesota based Control Data Corporation (CDC) in the 1980s. The CDC fab was acquired by Cypress Semiconductor in 1991. During the Cypress era, the facility was expanded and upgraded multiple times, keeping pace with Moore’s Law into the late 2000s and was known for being a US-based production facility that was competitive with Asian-based fabs. SkyWater spun-off from Cypress in 2017 with private equity backing from Minnesota based Oxbow Industries.
The course itself is very self sufficient, and on top of that you have the community behind it. People are happy to help and review your work. I would definitely recommend the course!