Counterfeiting of integrated circuit (IC) is a growing concern in the semiconductor industry. Counterfeiting involves economical and safety issues. Both semiconductor companies and embedded system designers are looking for traceability solution in order to get assurance in IC they use. This letter proposes to use Electromagnetic (EM) radiated emission from Integrated Circuits (IC) to create a unique fingerprint for each IC. We have proposed to use a variability-aware circuit configuration which would exploit EM fingerprint for each IC. Our measurement results on two different field-programmable gate array (FPGA) families over several test boards validates this scheme. As a last step, post-processing on the obtained EM measurements is done to get a unique FPGA signature which could be used for the purpose of authentication.