Fabrication of Two-Layer Thin-Film Magnetic-Field Microprobes on Freestanding SU-8 Photoepoxy

Development and testing of a two-sided magnetic-field microprobe using freestanding SU-8 photoepoxy as the insulating material are presented. Sputter-deposited thin-film silver conductors, patterned using a modified lift-off technique, were used as the loop and shielding traces on opposite sides of the SU-8 dielectric. Removal of the patterned probes from a silicon-carrier substrate was done by wafer dicing individual probes and undercutting a sacrificial silicon dioxide layer on the wafer surface. Assembly of the probe was accomplished using gold wire and electrically conductive epoxy on a printed circuit platform. Test measurement results indicate that the magnetic field from each of the two 500-¿m-wide circuit traces separated by a 100-¿m spacing can be readily resolved.