Manhattan

Manhattan geometry is a drawing style that uses only horizontal and vertical edges, like city streets that never cut a diagonal.

Most digital chips, and many boards, stay with that style because it is cheaper and safer to build and to check. Edges land on a grid. Width and space are easy to measure. Routers think in tracks. A 0.14 micrometer wire that only turns at right angles is a Manhattan wire. On screen it is a staircase of rectangles, or a path that snaps to 0° and 90°. Zoom in on a standard-cell block and almost every edge is axis-aligned.

Every leg is horizontal or vertical. The climb is a staircase.

The opposite habit is all-angle geometry: 45° bends, circles, waveguides, and package balls. Both can live in one file. Rules often get stricter when an edge is not Manhattan, because a spacing check must measure a true distance, not a simple Δx. Calling the style old misses why it remains. Manhattan is a manufacturing and tooling choice. Analog and photonics leave it when physics asks. Digital stays because a million wires need a discipline.

Routers, LEF tracks, and many DRC speed-ups assume Manhattan edges. A 0.14 micrometer pitch grid of horizontal metal 2 and vertical metal 3 is the usual fabric. A single 45° jog in that fabric is a special request. Keep the jog when physics needs it, and isolate it so the digital sea stays square. A diagonal next to a rectangle is Manhattan vs all-angle. A square ribbon that turns with a stair is paths: centerlines with width. How far that ribbon must stay from its neighbor is width and space.