It covers the materials and structures used to build back-end-of-line electrical connections in a semiconductor device, including copper interconnect formation, ruthenium liner materials, and low-k or air-gap dielectric layers that separate the conductive lines. The dataset is scoped by IPC classes H01L23/532, H01L21/768 and C23C16, which together capture interconnect structure, dielectric isolation and coating/deposition claims. It excludes front-end transistor materials and most packaging-level interconnect work outside those classes.

Filings rose from 6 in 2017 to a peak of 16 in 2020, then held roughly flat through 2022 before tapering toward the most recent tracked year. Part of that apparent decline is a publication-lag artefact: patents typically publish around 18 months after filing, so the last one to two years in any dataset are undercounted rather than genuinely quiet. The flat run from 2020 to 2022 is a more reliable signal that the core structural and material claim space had matured by that point.

Filing activity concentrates among a small group of large integrated device manufacturers, a dominant foundry, and semiconductor process equipment makers, with a long tail of smaller suppliers behind them. Recent-year momentum figures show zero filings in the latest tracked year across all of the leading assignees checked, which is consistent with publication lag rather than an actual halt. The full ranked assignee table, rendered separately from this prose, gives the exact order and family counts.

Relative to the dense core claim space around copper fill and low-k dielectrics, several adjacent branches show thinner coverage: ruthenium liner adhesion layers, air-gap dielectric formation sequencing, split barrier layers combining nitrogen- and oxygen-containing portions, and electroplating-based via fill under the C25D classification. These are not guaranteed-open — they are directions that warrant a targeted freedom-to-operate search before drafting a claim, given how much of the surrounding space is already occupied.

Heavily concentrated in the United States: 213 of the 295 tracked records have a US receiving office, versus 29 at the European Patent Office, 20 filed via the WIPO/PCT route, and smaller counts in the UK, Austria and Australia. That skew means US prior art sets the practical baseline for novelty and freedom-to-operate assessments in this field, with European and PCT filings worth checking separately for jurisdiction-specific gaps rather than assumed overlap with the US corpus.