SMD pads have the solder mask opening smaller than the metal pad, so the mask itself defines the exposed pad area; NSMD pads have the opening larger than the pad, so the copper edge is exposed and the mask plays no role in defining the pad boundary. The distinction matters for patent claims because a large share of the filings in this dataset, including highly cited records like US8232641B2, claim specific combinations or zone-based mixes of the two structures rather than either structure in isolation. Reviewing claim language for whether a patent covers SMD, NSMD, or a defined mix across substrate zones is the first filter for freedom-to-operate work in this area.

Filing is concentrated at the top: the leading assignee in this dataset holds 485 of the 4,149 records in scope, and the top five assignees combined account for 38.5% of all records, rising to 51.4% for the top ten. Beyond that group there is a long tail of smaller filers, so most freedom-to-operate and licensing due diligence should start with the ranked leaders before extending to the wider field. Recent-year momentum also varies sharply within that leading group, with some large filers showing year-over-year declines in latest-year filings even as their cumulative portfolios remain the largest in the field.

Filings rose from 153 in 2017 to a peak of 372 in 2023, then declined from 284 in 2021 to 229 in 2024, a 19% drop over that three-year window. Figures for 2025 and 2026 are still incomplete in any patent dataset because publication typically lags actual filing by around 18 months, so the apparent tail-off in the most recent years should not be read as a real slowdown yet. The more reliable read is the 2021-to-2024 comparison, which shows the field cooling modestly from its 2023 peak rather than accelerating further.