It personality based, talk about your likes and not likes, some technical, but just wants to see if you fit in. Nothing crazy, just trying to see if you're a good fit to the team off your vibes.

I got hired on after an intern conversion but I've sat in on some interviews. The core part is the technical presentation on a topic of your choosing (usually previous research) to your potential department. Followed by some panel interviews with different groups of staff.

Phone interviews are more behavioral and getting to know your background. If you proceed to final rounds, be prepared to give a presentation to the department about a project of yours and be able to answer in-depth questions about implementation and theory