Bump characterization with MR/GMR head as transducer

With a magneto-resistive (MR) head as transducer, this paper report a method and experimental results of fast in-situ characterization of laser textured bumps over disk surface. The thermally induced change of the resistance of MR head is used to conduct fast analysis of the uniformity of bump width, bump pitch interval, and bump height in the laser textured landing zone of a magnetic disk. Two modes of the tester setup are discussed. One mode is for the fast detection of the above mentioned uniformity within one disk revolution. Another mode is for mapping the selected bumps or all the bumps in a selected sector or a sub-zone of the textured landing zone. The setup can be used in both on-line and off-line analysis of the laser bump uniformity in media manufacturing process