I received the invitation through an Nisha. I was interviewed on site with two managers. The first one was a leading physicist and te second was the hiring manager. Each of them lasted an hour. After I passed these two interviews, I was asked to attend an HR on site screening. After this interview I did not hear from them for 3 weeks, and when I approached them they asked me to come again to receive the offer.

First were two professional interview with the managers who explains about the company, role and expectations from you. then following with a HR interview who goes to all ther details and benefits eventually offers the employment contract.