This is an interesting insight into the challenges of porting a TSMC fab from Taiwan to Arizona.
There are hundreds of variables that differ, even just based on geography, any one of which can kill nano-scale wafer yields and mean the difference between 90% ("printing money") and 30% ("bleeding cash") yields.
For example, the harder stone bedrock in Arizona has a higher natural resonant frequency than in Taiwan, requiring the fab design to be adjusted to that variable.
Other variables are local air, water, power, suppliers, and culture, all of which differ from Taiwan and require modifications to the original fab design.
TSMC Arizona: chipmaking is the art of killing variables [video] · HackerTrans
There are hundreds of variables that differ, even just based on geography, any one of which can kill nano-scale wafer yields and mean the difference between 90% ("printing money") and 30% ("bleeding cash") yields.
For example, the harder stone bedrock in Arizona has a higher natural resonant frequency than in Taiwan, requiring the fab design to be adjusted to that variable.
Other variables are local air, water, power, suppliers, and culture, all of which differ from Taiwan and require modifications to the original fab design.