First you do a half hour phone session. If good, you go on for a on site interview set. Lots of technical questions and some behavioral. I interviewed with some highly awkward and unprofessional people, along with a few good ones (Hiring manager included). One guy seemed like he was trying to stump me, bad attitude, abrupt, insulting and was very rude about my work, my thesis, etc. He also brought up borderline "illegal" questions that you should never ask anyone at the interview (actually a few of them did this). Most 1:1 interviews was just tech question after tech question with no look at my work, background or questions on who I am. They didnt care about much of me, only if I could answer a lot of technical questions and if I fitted in with them politically. Hiring manager was very kind, but seemed like he doesn't have enough say to keep people he likes. I did very well I thought, but since I didnt remember equations off the top of my head, especially after feeling extremely anxious being consistently and uncomfortably grilled (the guy said he was trying to stump me), I was suddenly labeled as I didnt know my stuff according to hiring manager when I talked to him after I was given a email decision by HR. I did however told him he forgot a negative once I did remember the equation, which he responded: well, I guess you are right, after he tried to prove me wrong....just bad. HR is kind, and the other folks are nice. Its a cubical farm with bad lighting, so I am not that disappointed, however I dont like being told I dont know my material if I cannot remember an non-typical equation that I dont use daily. HR being located in a different time zone and disconnected from opposite coast does not help this process, but they are very professional and kind if you have any concerns or questions.