Comment by culi

For multi-patterning DUV, each patterning/etching step accumulates defect risk. Actually now that I'm reading about it, 20% is the better end of the spectrum. I don't think technology could possibly improve it much beyond that.

I believe the theoretical maximum yield for multi-patterning DUV at 5nm and 7nm is 30-40%

It's not economically sustainable/viable long term. China is only doing it because they've been forced to by the trade war Trump started against them in his first term (Biden didn't really back down either and now Trump 2 tried to ramp it up even higher). China is okay with such low yields because its supposed to be a temporary solution until they achieve domestic EUV tech.