Data contracts / ledger

Defect density (D0)

Point-in-time daily ledger of Defect density (D0) — every move dated and sourced.

Coverage window

2026-06-07 → 2026-08-27 (844 rows)

Computed from the backing series at page-render time — never typed by hand.

History honesty

History accrues in place from the ledger start (2026-06-06) — append-only, never backfilled; depth before the start cannot exist.

Cadence

Ledger snapshots daily at 08:00 UTC; movements appear only when a value actually moves. Empty window = nothing moved.

Revision policy

Append-only: a frozen day is never edited or deleted (database-enforced). Corrections are registered in data_corrections and served alongside; restatements surface via /api/v1/changes.

Sources (source)

Analyst Consensus, Initial Yield Reports (162) · Analyst Consensus based on ~50-60% Yield Reports (162) · Industry Expert Consensus (Mature FinFET) (104) · TechInsights Teardown Analysis, Analyst Reports (81) · Industry Expert Consensus (Historical Challenges) (81) · Industry Expert Consensus (Mature Planar) (81) · Based on historical 0.09 IEDM disclosure + Improvement (79) · Industry Expert Consensus (Samsung EUV, penalty vs TSMC N7) (23)

Known gaps

Known-gaps review pending — the coverage boundaries above are computed and current, but the curator’s qualitative gaps assessment has not been written yet. We state that rather than inventing one.

Access

Fully open

API: /api/v1/snapshot

Machine-readable

/api/v1/catalog/ledger-defect_density/contract