An integrated circuit is provided. The integrated circuit includes an RFID tag configured to store various administrative information after testing at a wafer level in response to a radio frequency signal, and an interface unit configured to perform the function of an interface between the integrated circuit and the RFID tag for storing the information in the RFID tag. An antenna of the RFID tag is formed using a wire and a lead frame. A method for writing information of an integrated circuit is also provided. The method includes the steps of performing a wafer processing of an integrated circuit having a RFID tag; performing a wafer level test of the integrated circuit; transmitting and receiving a radio frequency signal to store various administrative information in the RFID tag; and storing a chip confirmation code in the RFID tag.