Inspection processes for read/write heads require high-precision non-contact metrology functions to control tight Z-axis tolerances in the read/write gap measurements and Z dimension variations from the side rails to the top surface of pole-tip features.
Metrology platforms for head inspection must therefore supplement their X-Y edge-finding capabilities with fast and accurate Z-axis functions, using either highly repeatable video auto-focus or integrated laser options to capture critical 3-dimensional features.