It depends on your present education or to be more precise your present academics.

If you are still in class 12th then you can join IISc Bangalore for the 4 year Science course by qualifying JEE exam. It is totally a research oriented course.

If you are in graduation I.e engineering then you can join IISc by qualifying GATE exam.

You will have to achieve under 100 rank to get IIsc.

All the best!!