An inventive method tracks IC devices through the assembly steps in a manufacturing process. Prior to die attach, a laser scribe marks the lead frame of each of the devices with a coded hole matrix that gives each device a unique ID code. During die attach, an optical hole reader retrieves the ID code of each of the IC devices, and a computer system stores the retrieved ID codes in association with the lot numbers of the ICs attached to the lead frames. The ID codes of the devices are then read at each step in assembly so the devices can be tracked through assembly individually, rather than by lots. As a result, the devices can proceed through assembly in a more efficient, continuous manner (i.e., without breaks between lots).