Fig. 2: Self-assembled micro-coils (exemplified for coil pair sample design).
From: Tailoring electron beams with high-frequency self-assembled magnetic charged particle micro optics
a Sketch of the microfabricated layer stack and structures before the self-assembly process with a micrograph of four adjacent structures on the wafer. The planar structure has a width of wc = 1.8 mm and is as long as the conductor stripe (length lc = 2.6 mm) with a width of 50 µm, which later on forms the micro-coil. The structures contain openings forming an aperture for the electron beam. b Sketch and micrograph of the self-assembled micro-coils which are produced by etching of the sacrificial layer (SL) and swelling the hydrogel layer (HG). The conducting metal layer is placed on top of a polyimide layer (PI) c 6-inch wafer with 1069 out of 1214 functional integrated micro-coils. d Generation of magnetic field with a micro-coil when current passes through the conductor. e FEM simulation of the magnetic flux density generated by a coil driven by Ic = 100 mA current shows that the coil can provide high fields of about 3–4 mT. f Distribution of the maximum breakdown current for the micro-coils fabricated on one wafer reveals a mean break down current of 93.0 mA. g The axial magnetic response of the soft ferromagnetic microwire (inset) with the transversal anisotropy reveals almost linear hysteresis free field dependence in the range from −0.2 to 0.2 mT external field.
