Making PhD engineers operate/maintain/monitor a wire bonding machine seems expensive.
I worked in an R&D fab (albeit, as an intern, many years ago) with an abnormal number of PhDs around (the fab was essentially a small scale test bed for new products and processes - everything tested there first before scaling up overseas). I think we had a 5:1 ratio of techs to engineers. This was in a fab that basically did nothing but R&D and low volume manufacturing for defense.
It's comparable to any kind of high-tech manufacturing where you have engineers designing/testing stuff (and designing the tools to make and test the stuff in the first place) while there have to be techs/mechanics/machine shop workers to actually do the work of making it. It's inefficient and expensive to put the engineers on that task, while they'll still need to do it from time to time.
I worked in an R&D fab (albeit, as an intern, many years ago) with an abnormal number of PhDs around (the fab was essentially a small scale test bed for new products and processes - everything tested there first before scaling up overseas). I think we had a 5:1 ratio of techs to engineers. This was in a fab that basically did nothing but R&D and low volume manufacturing for defense.
It's comparable to any kind of high-tech manufacturing where you have engineers designing/testing stuff (and designing the tools to make and test the stuff in the first place) while there have to be techs/mechanics/machine shop workers to actually do the work of making it. It's inefficient and expensive to put the engineers on that task, while they'll still need to do it from time to time.