Text Shorts in LVS

A text short is when the same net shape, pin shape, or substrate layer carries two different labels. Technically it is just a labelling conflict, so strictly speaking there is no electrical risk. However, it should still be fixed before tape-out, because a text short can mask a genuine problem - for instance two truly different nets that happen to share a label, or an actual open. So it is not safe to tape out with a text short unresolved.

KEY A text short is one shape carrying two labels - electrically harmless, but it can hide a real short or open, so fix it before tape-out.

Antenna Violations at 28nm

At 28nm there are two kinds of antenna violation.

• The first is the metal-area to gate-area ratio on a single layer.
• The second is the cumulative metal-area to gate-area ratio across layers.

Etching is done layer by layer, and even if charge is removed after each lower layer, small amounts can remain or build up again. Collectively this residual charge can still destroy a gate, because at smaller nodes the gate is very short and extremely sensitive to slight charge build-up. In cumulative-area mode the tool considers metal segments on the current layer plus all lower-layer segments, computing antenna_ratio = all connected metal areas / total gate area.

KEY 28nm shows single-layer and cumulative antenna violations; residual charge across layered etching can still destroy the sensitive short-channel gate.

Increasing the GRC Cell Size

No. ICC gives the user no control over the GRC (global routing cell) size. It is calculated dynamically by the tool and is not a fixed value; by default the GRC width equals the standard-cell row height.