After attending an information session at my graduate school, I received a phone call that could have been considered a "phone interview" consisting of me explaining my graduate work, offering some time for me to ask questions, and ending with an invite to the Intel campus for an onsite interview. The call lasted 20-30 minutes.
The onsite interview started with a 1 h presentation of my graduate work followed by three 45 min interviews (2 technical, 1 behavioral) and lunch with an engineer. The technical interviews started with my elevator pitch of my graduate work followed by follow up questions from the interviewer with time for me to ask questions of my own. The behavioral questions were akin to those that can be found via an internet search, e.g. "How have you handled a conflict with a supervisor in the past?" All in all, the interviews were informal and conversational.