The most-cited records in this corpus include filings on multilayer mirror deposition, assist layers, PECVD films, and maskless microlens systems, with citation counts ranging from roughly 238 to 308 within the searched dataset. These older filings, several dating to the early 2000s, established foundational claims that later entrants had to design around. Current top filers by volume include the leading EUV scanner maker and major optics suppliers, though recent-year momentum data shows most of them with zero new filings in the latest year, reflecting the broader slowdown across the field rather than any single company's retreat.

Filing volume peaked at 58 families in 2022 and has been flat or declining since, based on 829 total families tracked from 2015 through mid-2026. This pattern typically appears once a technology's core architecture stabilises — in this case, EUV scanners moving from development into production deployment at leading foundries. It does not mean innovation has stopped; it means new filings are more likely to refine existing source, mirror and dose-control designs than to stake out entirely new platform approaches. Publication lag of roughly eighteen months also means the final one to two years of any trend are undercounted.

817 of the 829 families in this dataset carry a G03F classification, the core photolithography and photomechanics subclass, making it by far the most contested claim territory. Semiconductor devices (H01L, 206 records) and optical elements (G02B, 161 records) are the largest adjacent areas. Particle and radiation handling (G21K) and X-ray technique (H05G) each carry under 100 records, suggesting source-hardware and radiation-handling claims are comparatively less crowded than mirror and mask claims within the core subclass.

Based on IPC distribution, the classes adjacent to the core G03F cluster — particularly G21K (particle and radiation handling) and H05G (X-ray technique) — carry substantially lower filing volume than the core subclass, at 95 and 91 records respectively against 817 in G03F. That gap points to source-hardware and radiation-handling sub-areas, such as source-power recovery mechanisms and in-situ stochastic defect detection, as places where claim space may be less occupied. Any white-space read should be confirmed against the specific prior art in that sub-area before committing a filing strategy, since thin IPC counts can also reflect indexing practice rather than genuine gaps.

Receiving-office data shows filings concentrated heavily in the United States (500 filings), with the PCT route (101), Europe (99), Taiwan (30), Japan (19) and the Netherlands (14) following well behind. On the assignee side, co-filing is rare — only 10 co-assignee pairs exist across all 829 families, and the strongest links tie a single optics supplier to named inventors and university groups rather than to other manufacturers. That combination of a few dominant filing venues and very limited collaboration suggests IP in this field is built largely in-house within a small number of organisations.