Built-in electrical test structures are measured for lead-to-lead shorting
during the fabrication of MR elements on a wafer. The test structures are
fabricated in the same fashion as the MR elements, however, the active
sensor region or track width is omitted from the test structures. Thus,
the left and right leads for each test structure are electrically
isolated from each other in their "track width" region. If there is
lead-to-lead shorting on a test structure, then the left and right leads
are electrically connected in the track width region. A simple resistance
measurement between the left and right leads determines the extent of any
lead shorting by giving a quantitative resistance value.