The Electrical OverStress (EOS) event is a transient surge with the microsecond time length. Due to the huge energy of the EOS surge and its low-frequency noise characteristics, it causes the IC chip to be easily damaged beyond its maximum tolerance. The common EOS burns are the burning of the metal layer of the wafer to form a charred black block. In addition, the Bonding Wire connecting the die pad and the package pin would also be blown by EOS. If there is a larger EOS surge energy, the appearance of the package would also be burned until it is damaged and deformed.