Whether it is Qualcomm or any other organization, the criteria for hiring students remains the same-look for the brightest one.
There is no magic for getting into Qualcomm, it is a simple routine procedure. Firstly, you have to get shortlisted for interview by clearing their technical and aptitude test, which covers questions from various courses taught in Electronics during the span of four years.
Now that you have been shortlisted, you need to go through a minimum of two technical interviews and one HR interview. The number of interviews may increase depending on their choice. (Usually this happens if they have to choose between two closely matched students)
Questions asked in interviews are regular ones, which you should be able to answer if you have put in a fair bit of effort in that course. They also ask a few reasoning questions to test your problem solving skills. That apart, they judge you on your confidence level and presence of mind, apart from you CGPA, your research and academic history (including even your rank in JEE Mains and Advanced). I agree this is not a criteria to get selected, however it does provide an insight as to how good a student he/she is.
HR interviews are usually not eliminators, though I have seen a friend of mine getting eliminated after HR. I have no idea why such a thing happened.