forbidden¶

What a rule forbids outright. An operation over the rule’s layers has to come out empty, and every region it leaves is a violation. Without an op the layers themselves are forbidden: a derived layer whose whole purpose is to compute the error set, or a layer the process simply doesn’t support in this flow. With one, the residual of a boolean or a selection over the listed layers is.

Semantics¶

op chooses what is read:

(none): Every connected region of every listed layer. Used for marker rules whose condition is “this geometry must not exist”, typically a derived layer such as antenna Ant.i’s pactiv_con ∩ Recog.diode − Recog.esd − (NWell ∪ PWell.block), the set of p-diodes sitting outside any well; and for device layers a flow doesn’t support at all. An edge layer is read the same way, one violation per segment.
uncovered: The part of layers[0] that the union of the remaining layers leaves bare: target − (cover₁ ∪ cover₂ ∪ …). Unlike min_enclosure, this handles “covered by A or B” directly and flags a target that misses the cover entirely, not just one short on margin. With scope: polygon the whole target polygon is reported whenever any part of it lies outside the covers, once, instead of its bare parts.
overlap: The geometric intersection of all listed layers: “A on B is not allowed”.
apart: The regions of layers[0] that touch none of the remaining layers: “every MIM cap needs its via”. A shared edge counts as touching. With rows and cols a region is apart unless it holds an array of the one partner layer at least that large, at one location: the rows and columns are only an array if every crossing holds a partner, so four vias in a line or bent into an L do not pass for a 2×2, and value is how far apart two rows may be and still be one location (GF180 MT30.8: a via is small against thick top metal, one of them is not a connection). Vias are lined up into rows and columns by their markers, with a tenth of value as the tolerance for the drift within a row.
touching: The regions of layers[0] that touch any of the remaining layers, a shared edge included: “marker X must not touch Y”.
beyond: Every shape on every other layer of the layout past the outer edge of layers[0], typically the seal ring. The boundary layer is merged, its largest region taken as the ring, and the bounding box of that region’s outer contour is the edge nothing may cross. A shape with a vertex outside is flagged once, at that vertex. Layers listed in the rule’s ignore are skipped.

Every reading but beyond is evaluated as a derived layer on the tiled merge cache (Virtual layers) and read as stitched regions, so a region spanning several tiles is reported once and no layer is unioned globally. beyond reads the raw layout, since it looks at every layer there is; it is the one check that needs the whole layout flattened, and a deck using it cannot point it at a lazily built derived layer.

An exemption by label: a rule with a text and a label layer param drops every residual region carrying a text on that layer which matches text (exact, or a prefix when it ends in *). A marked structure is the designer’s word that the region is meant.

Layers¶

(none), beyond: One or more layers, all forbidden; for beyond the one boundary layer.
uncovered, apart, touching: layers[0] is the target, layers[1..] the covers or partners, read as their union.
overlap: Two or more layers, whose common intersection must be empty.

Parameters¶

op: uncovered, overlap, apart, touching or beyond; absent for the layers themselves.
scope: part (default) or polygon; with op: uncovered only.
rows / cols: With op: apart only: the array of the partner a region must hold, either one defaulting to 2; value is then the reach between two rows of it in µm.
text with layer_params: label: The exemption label and the text layer it is drawn on.

value is unused otherwise (set it to 0.0 by convention).

Violation markers¶

One point violation per residual region, at a representative point inside it; one edge violation per segment of a forbidden edge layer; for beyond, one point per offending shape at its first vertex outside, tagged with the raw GDS layer and datatype it came from.

KLayout equivalent¶

layer.output(...) on an already derived layer; target.not(c1.join(c2, …)); target.not_inside(c1.join(c2, …)) for scope: polygon; a.and(b, …); target.not_interacting(p1.join(p2, …)); target.interacting(p1.join(p2, …)); and every drawn shape outside the ring’s extent, filtered by an ignore list, for beyond. The exemption is .not_interacting(candidates.interacting_with_text(...)).

Examples¶

- id: npnG2.b
  check: forbidden
  layers: [NpnTieNoTrans]
  value: 0.0
- id: Cnt.g
  check: forbidden
  layers: [ContSquare, Activ, GatPoly]
  value: 0.0
  params:
    op: uncovered
- id: Cnt.j
  check: forbidden
  layers: [ContOnGatPoly, Activ]
  value: 0.0
  params:
    op: overlap
- id: MIM.h
  check: forbidden
  layers: [MIM, TopVia1, Vmim]
  value: 0.0
  params:
    op: apart
- id: MT30.8
  check: forbidden
  layers: [mt308_x, mt308_via]
  value: 2.0
  params:
    op: apart
    rows: 2
    cols: 2
- id: Seal.l
  check: forbidden
  layers: [EdgeSeal]
  value: 0.0
  params:
    op: beyond
  ignore:
    - Passiv
    - Pad