I worked in Government R&D microdevice fab for years and it was a lot of fun but hard work. What made it fun is always working on something new and challenging (inventing new processes), but in a relatively low stress environment with a lot of other absolutely brilliant people (like I was dumbest person in the room, all the time, every time).

I would not consider working in a production fab for the going salaries these days... mostly boring work, on-call all the time, in bunny suit most of the day, bean-counters controlling all of the major decisions. Screw that... life is too short and we all die at the end.