Dear Fellows, I am using AZ50. I got the data sheet relating film thickness and spin speed. But the thickness I got is always significantly less than the suggested values. E.g., 1250 rpm for 40 um (from curve: 55), 1000 rpm for 50 (lately got 40 often) um (from curve: 65), and 750 rpm for 60 um (from curve: 85). I got this PR recently and it is just manufactured, and I use it when the PR warmed up to room temperature. If there is some advice you can provide me? Thanks, Happy Lunar Dog Year, Zeta Tak For Yu