I am in M.Sc.Biotech 2nd sem. I wanna pursue my 4th sem 6 months project training in USA. Is that a good idea or should I do it in India ???

It's a good idea to do something like this in USA if you are planning to apply for phd in the us, it will be a good add value for your phd application. As always its easier to do such projects india due to easy accessibility and feasibility and this would also be recognized while applying for phd.