On campus interview for PhD engineering students. The recruiter asked only the behavior questions focus on collaboration, conflict, leadership, research creativity and weaknesses. They said it would take 3-4 weeks for the final decision.

Dow Chemical has this on-campus recruiting every year in August. After initial resume screening, you'll be invited to talk to one or two engineers from Dow on your campus (~45 min long). If they like you and rate you top 1 or 2 out of 10, an on-site interview will be conducted in one or two of their sites. It's a full day interview starts with a 45 min technical presentation followed by 6-7 one on one interviews. The waiting period after that was brutal (mine lasted for 7 weeks), and you need patience. But an offer will be extended to you once they make up their minds. Overall it's a very stressful but also enjoyable process, you'll have the opportunity to meet a lot of top engineers in the field. People at Dow are very nice and smart, my overall suggestion is to be confident and well prepared.