they called me for an HR phone screening where they asked me some behavioral questions then i talked to the Hiring manager who asked about my interest, resume, etc. then i had many rounds of interview with people within the department who asked me about my resume, research experience, etc.

Multi-stage behavioral based interview. The interviewers were professional and friendly. Questions ranged from experience to times where challenges were faced. The overall experience was good even though an offer was not made.