The on-site interview process was a full day long, starting at 8:00 am and culminating in a dinner at a bowling alley ending at 10:00 pm. This was part of a college recruiting event, so I was one of five or six interviewees from several colleges. I had first spoken to Hillcrest at a career fair at my university, and they followed up with an on-campus interview. The on-site interview was a few weeks later.
There were several interviews, which mixed behavioral and technical questions. There was a "survey" which was formatted like a school exam, asking technical questions about various fields related to what the company does (electrical engineering, signal processing, geometry, programming), which we were given ample time to complete, though I spent far too much time on the geometry question. It was stressed that it is okay if we couldn't answer all of the questions, so I assume that the role of this survey was to determine what departments the candidates would best fit in, given their expertise.