max_space¶

Maximum proximity distance: everything of a target layer must lie within value of a reference layer. Used for latch-up rules such as “every source/drain diffusion must be within 20 µm of a well tie”, for well-tap rules such as “a diffusion must have a tap within 15 µm”, and for guard-ring rules such as “every edge of the well is within 15 µm of the ring”. scope says what has to be in reach: every part, every polygon or every edge.

Semantics¶

This is a coverage/reach check, not a spacing check: it doesn’t flag two regions that are too close, it flags what of layers[0] is too far from any region of layers[1]. It reads backwards from the rest of the engine — a spacing rule fails on the closest pair and is satisfied by there being nothing nearby, while this one fails on the absence of a neighbour, so an empty reference layer makes everything a violation rather than nothing.

scope: part (the default): Every part of the target must lie within value of the reference; any part that does not is flagged, wherever on a shape it is. The reference is grown by value with a square structuring element (what KLayout’s sized gives rectilinear geometry) and subtracted from the target; what is left is stitched across tiles and reported once per gap.
scope: polygon: Every polygon of the target must have some part within value of the reference; a polygon that has none is flagged as a whole. The same grown reference, tested per region: a wide active block passes once its tap is in reach of any of it, where part would flag the far side of the block. A polygon exactly value away is in reach, as KLayout’s interacting counts a touch; one a DBU further is not.
scope: edge: Every edge of layers[0], an edge layer, must have layers[1] within value at some point along it; an edge with none is flagged. The partner is gathered by tile lookup over the edge’s own box grown by the limit, since an edge is not clipped to a tile.

Both region readings run on the tiled merge as core pieces — neither layer pays the value as a halo, and a dense reference such as the contacts on ties is never globally unioned.

Layers¶

layers[0] — the target that must stay close to something (an edge layer under scope: edge).
layers[1] — the reference geometry it must reach.

Parameters¶

scope: Optional. part (the default), polygon or edge, as above.
reach: Optional. square (the default) grows the reference by the value in each axis, which is what KLayout’s sized gives on rectilinear geometry, so a target diagonally off a corner is in reach out to the value in each direction. round grows it by the value in any direction, which is what a rule worded “max distance” means: GF180’s DF.13 and DF.14 read it that way, and upstream approximates the disc with an octagon (“to approximate a circle”).
within: Optional layer param (under layer_params), with scope: part or polygon. Confines the reach to that layer: the reference is grown in half-micron steps and cut back to the layer after each, so the reach goes round a slot in the layer and never crosses the gap to another region of it. This is how the GF180 well-tap rules read — the tap is grown inside the well, in steps under the well’s own spacing — so a diffusion on the far leg of a U-shaped well has no tap in reach across the slot however near the tap lies, and a tap in a neighbouring well is no tap for this one. Under part the confined reach is what is subtracted from the target. The steps are whole DBU and add up to the value exactly, since each grow snaps to the grid.

Violation markers¶

Under part, one point marker per gap, in the part of the target beyond reach. Under polygon, one point marker per unreached polygon. Under edge, the edge itself.

KLayout equivalent¶

Not a single built-in operator. part is target.not(reference.sized(value)); polygon is target.not_interacting(reference.sized(value)), the construction the GF180 deck uses for its well-tap rules; edge is the complement of a separation in its edge form — measure where the separation is within the limit and keep the edges that do not touch it.

Examples¶

- id: LU.a
  check: max_space
  layers: [PsdActivInNWell, NActivInNWell]
  value: 20.00
  layer_params:
    within: NWell

- id: DF.13_MV
  check: max_space
  layers: [pactive_56v, ntap]
  value: 15.0
  params:
    scope: polygon
  layer_params:
    within: nwell

- id: MDP.4b
  check: max_space
  layers: [mdp4b_edges, mdp4b_pcomp]
  value: 15.0
  params:
    scope: edge