Focused Ion Beam Milling Simulator — Top-Down 2D

A focused ion beam (FIB) system fires a finely focused stream of gallium ions at a solid surface and mills away material atom by atom through physical sputtering — no mask, no chemistry, no resist, unlike optical or electron-beam lithography. This 2D companion to the 3D FIB simulator renders the exact same Sigmund/Yamamura-style angular sputter-yield model as a bird's-eye heatmap: tilt the incidence angle and watch the yield rise as the collision cascade moves closer to the surface, peak at θ≈58°, then collapse again near grazing incidence as ions reflect instead of embedding. Pick a mill pattern — an open-area box, a line trench, an alignment cross, or a circular via — set the beam dose, pan and zoom the grid, and watch a live cross-section profile build up alongside the top-down view with real sputter-yield, mill-rate and depth readouts, exactly the mechanism used to prepare TEM lamellae and edit circuits in real fabs.