A method of assembling a flip chip on a leadframe package. A locking dual leadframe (LDLF) includes a top metal frame portion including protruding features and a die pad and a bottom metal frame portion having apertures positioned lateral to the die pad. The protruding features and apertures are similarly sized and alignable. A flipped integrated circuit (IC) die having a bottomside and a topside including circuitry connected to bond pads having solder balls on the bond pads is mounted with its topside onto the top metal frame portion. The top metal frame portion is aligned to the bottom metal frame portion so that the protruding features are aligned to the apertures. The bottomside of the IC die is pressed with respect to a top surface of the bottom frame portion, wherein the protruding features penetrate into the apertures.