Ion beam etching is a microfabrication process essential for fabricating Josephson junctions. Josephson junctions, which involve nanometer-thick insulating and superconducting layers, require extreme precision. Ion beam etching selectively removes only unnecessary components, creating a clean and uniform junction surface and optimizing intermetal contact characteristics to ensure stable supercurrent flow. This precision processing technology is a key enabler for high-performance qubit implementation and large-scale quantum chip fabrication.