Consisted of 3 interview phases. 1) Approx 1-hr individual phone interview with HR representative. 2) approx 1.5- hr Individual F2F interview with hiring manager, and 3) a 3-hr panel interview with 5 engineering leads from varous levels and areas of the company. In my case, thois was followed up by additional individual interviews/introductions with various leads and several lab tours. These 3 phases were all spread out over 4 weeks, with the final panel interview and toure lasting all day. It was very intense, and based as much if not more on how I handeled stress and rediculously short deadlines as it was on my technical knowledge. Lots of subjective philosophical questions on "how would you handle this situation with a upstream supplier or engineering team", etc..