Shah Sharath

Am doing third year mechanical engineering and am very much interested in doing my master degree will it help for me to place in R&D sector what else i suppose to do

'Will it help' - Yes it will. But will it 'ensure' that you get a job - no.

Masters degree would be a right step in the direction in which you wish to move. But finally getting a job that you dream of is dependent on several parameters. Your best bet is to find out the skills / experience / education / certifications your dream job requires and start working on acquiring them. Does this answer your question?