Backside GMR Magnetic Microscopy for flip chip and related microelectronic devices

The applicability of GMR Magnetic Microscopy for current paths on flip chip die and interposer is shown. For non thinned samples (200 mum die thickness), interposer currents may be attributed to the interposer signal routing in the 1 mA current regime. With decreasing die thickness the discrimination of on-die currents versus interposer currents becomes possible. Below about 80 mum die thickness, on-die current paths, carrying sub-100 muA currents may be identified by comparison with die layout.