Fig. 1: The schematic and advantage of standing ceramic circuit boards (S-CCBs) and mechanism of the fabrication procedure of sacrificial-coating-assisted electric-field-driven (EFD) micro-3D printing.

a The schematic of commercial ceramic circuit boards (CCBs) with a large line width and low film thickness. b The schematic of S-CCBs with a small line width and large film thickness. c Chart comparing line width versus film thickness for different fabrication methods. DBC direct bonding copper^17,18, IJP inkjet printing^18,19, AJP aerosol jet printing^49,50, DPC direct plating copper^19,20, LAM laser-activated metallization^21,22,23,40, SP screen printing^24,25,26, LPBF laser powder bed fusion²³. The inset demonstrates cross-section of the wire of CCBs and S-CCBs, W_s is line width, H_s is the film thickness. d The uneven charges distributed on the rough Al₂O₃ causes unstable jet, e charges distributed uniformly on the sacrificial coating (SC)-Al₂O₃ makes a stable jet. f The change of electric field intensity along the X-axis on the surface of Al₂O₃ and SC-Al₂O₃. g The silver wires cannot be stacked with high aspect-ratio (AR) on the Al₂O₃, h fine silver wires with high AR can be printed on the SC-Al₂O₃. i Contact angle of the silver paste on the Al₂O₃ and SC-Al₂O₃. j The silver wires shrink locally on the Al₂O₃ with holes, k the silver wires shrink uniformly on the SC-Al₂O₃. l Thermal gravity (TG) analysis curves of the silver paste with/without sacrificial coating. m The appearance of a circuit on the Al₂O₃ substrate with a line width of 40 μm and size of 45 mm × 45 mm, which is similar to the resolution of the commercially printed circuit board (PCB). n A scaled integrated circuit with a line width of 10 μm and size of 5 mm × 5 mm. o The high magnification image of subfigure (l). p The SEM image of a 4 layers printed silver wire with a line width of 10 μm and an AR of 1.37 (thickness of 13.7 μm). Source data are provided as a Source Data file.