I had 3 interviews, total process took ~2 weeks.
I applied for the internship position and also forwarded my resume to a recruiter through a friend who worked at Tesla. Recruiter responded back quickly and scheduled an interview in few days. However, he canceled the interview because the position was filled by that time. Again, in few days, the recruiter contacted to ask me if I am interested to have a position at Gigafactory at Reno. He then scheduled an interview with the hiring manager. It was 30 minutes interview, the manager asked me about my research and works and why I chose specific process/material etc. I got a response within a day and the recruiter scheduled another interview with my potential mentor. That interview was more technical, he asked me about my research and asked some textbook questions related to crystal structure-mechanical property relation, and relevant heat treatment, how to choose a material for a job etc. After that, I heard back from the recruiter about another interview with my on-site manager at Reno (the actual hiring manager works from Palo Alto). It was more like a behavioral interview, he asked me about what I do in my pastime etc. These 3 interviews happened in 5 days. I got an offer letter in the early next week.