Solder Alloy Patents: Who Leads, Where the Gaps Are 2026
- Filing has cooled since its 2018 peak. 231 families published that year against a partial 3 in the latest year, with the 2022 midpoint of 102 confirming a flat-to-declining trend rather than a slowdown that just looks that way because of publication lag.
- B23K and C22C dominate the claim space. 3,371 records sit in welding/soldering/brazing and 2,193 in alloys, meaning most defensible ground in joint composition and process has already been staked out by incumbents.
- Consolidation shows up in co-assignee pairs, not new entrants. The strongest co-filing relationships link established solder-industry names filing 43, 37 and 16 shared families respectively — evidence of joint R&D among incumbents rather than a wave of new competitors.
Filing growth compares 2021 (208 records) with 2024 (74) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 3,832 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks 3,832 patent families filed between 2015 and mid-2026 that combine solder alloy or solder paste terminology with claims touching intermetallic compound formation, wetting behaviour, thermal fatigue, reflow profiles or joint reliability, filtered to the B23K35, H01L23 and C22C13 IPC classes. That combination captures the metallurgy of the joint itself rather than the broader universe of surface-mount assembly or PCB design.
Because publication lags filing by roughly 18 months, the last one to two years in any trend chart will always look thinner than they eventually turn out to be. The receiving-office spread — concentrated in the United States, Europe and Japan with a smaller but real China and PCT presence — points to a field still prosecuted mainly through the traditional electronics-manufacturing centres.
Filing trend and technology composition
Two views of the same 3,832 families: how filing volume has moved year over year, and which IPC subclasses carry the claim density.
A peak in 2018, then a plateau
Filings ran from 124 in 2017 up to a peak of 231 in 2018, back down to 102 at the 2022 midpoint, and down further toward the partial count in the latest year. Read the tail end cautiously — recent filings are still publishing — but the shape from 2018 to 2022 alone is a real decline, not an artefact of lag.
Claim density concentrated in joining and alloy classes
B23K (welding, soldering and brazing) covers 3,371 of the 3,832 families and C22C (alloys) covers 2,193, meaning most records claim either the joining process or the alloy composition itself. H05K and H01L appear at meaningfully lower counts, and B32B and C23C are thin at 70 and 59 respectively — the layered-product and coating angles on solder joints are comparatively open.
Shares are the percentage of the 3,832 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Solder Alloys and Interconnect Metallurgy with Eureka
This page is one run against one query. Ask Eureka your own question about solder alloys and interconnect metallurgy and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this space
Lead-free solder alloy, solder ball and electronic member (NIPPON MICROMETAL CORPORATION, 2009)
A lead-free Sn-Ag-Cu solder alloy tuned with small additions of Ni (1.0-2.0% Ag, 0.3-1.0% Cu, 0.005-0.1% Ni, balance Sn) to improve impact and vibration resistance. The claims specify how the intermetallic layer forms at the Cu electrode interface: a Cu3Sn layer directly on the Cu electrode, with a Cu6Sn5 layer forming on top of it, and control over the Cu atomic site substitution in that structure.Filed pre-dataset (2009) but still a foundational reference for Ni-doped SAC alloy claims within this corpus.
View full filing| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6165885A | Method of making components with solder balls | 271 |
| 2 | JP1986075553A | Electronic part | 234 |
| 3 | US5492266A | Fine pitch solder deposits on printed circuit board process and product | 219 |
| 4 | US6224690B1 | Flip-Chip interconnections using lead-free solders | 201 |
| 5 | US5261593A | Direct application of unpackaged integrated circuit to flexible printed circuit | 196 |
| 6 | US5872051A | Process for transferring material to semiconductor chip conductive pads using a transfer substrate | 190 |
| 7 | US5985456A | Carboxyl-containing polyunsaturated fluxing adhesive for attaching integrated circuits | 180 |
| 8 | US6337445B1 | Composite connection structure and method of manufacturing | 176 |
| 9 | US5327013A | Solder bumping of integrated circuit die | 176 |
| 10 | US5520752A | Composite solders | 167 |
Citation counts inside a searched corpus favour older filings that have had more time to accumulate citations; treat this as a map of influential prior art, not of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three read-throughs from the trend, classification and citation data that matter more than the raw counts.
The composition-tuning wave has largely broken
Filings peaked in 2018 and were already down to 102 by the 2022 midpoint. That decline predates the recent-year publication lag, so it reflects a real cooling in new solder-composition filings rather than a reporting gap.
Process claims outnumber pure-alloy claims
More records sit in B23K (the joining process) than in C22C (alloy composition alone), suggesting reflow profile, wetting and joint-formation claims are as contested as the metallurgy itself. A new filing needs to clear both fences, not just the compositional one.
Consolidation runs through partnerships, not acquisitions
The strongest co-assignee relationships in the dataset link established solder manufacturers and chemical suppliers, with the top pair sharing 43 families. That points to joint development agreements as the mechanism holding this field together, rather than single-company dominance.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to solder alloys and interconnect metallurgy, with the prior art for and against each one.
Who holds the ground, and where it is open
Momentum has flattened across the named assignees tracked in the latest year, several showing a full year-over-year drop to zero filings. That is consistent with the overall filing decline rather than any single company exiting the field.
Legacy solder manufacturers have pulled back new filings
Several of the longest-standing names in this dataset show zero filings in the latest tracked year, some down -100% year over year. This reads as a mature claim position being maintained rather than actively extended.
Joint R&D pairs cut across alloy suppliers and electronics makers
Co-assignee pairs link solder-material specialists with major electronics manufacturers, indicating that new alloy work is increasingly validated jointly with an end-use partner rather than filed solo.
Prosecution still centres on the US, Europe and Japan
The United States and EPO together account for the largest share of receiving-office filings, with Japan third and China and PCT filings smaller but present — a signal that enforcement strategy in this field still runs primarily through traditional manufacturing jurisdictions.
| Assignee | Recent year | YoY |
|---|---|---|
| Senju Metal Industry Co., Ltd. | 0 | -100% |
| Senju Sperian Co., Ltd. | 0 | — |
| Indium Corporation | 0 | -100% |
| Alpha Assembly Solutions, Inc. | 0 | -100% |
| Panasonic Corporation (Japan) | 0 | — |
| International Business Machines Corporation (IBM) | 0 | — |
| Alpha Metals, Inc. | 0 | — |
| Alpha Setec Chemicals and Solder Industries Pte Ltd | 0 | — |
Where to take this analysis
The landscape points to a mature, consolidating field with specific thin spots. These are the natural next steps for a freedom-to-operate or whitespace review.
Map the intermetallic-layer claim thicket
The most-cited prior art and the representative filing both centre on Cu3Sn/Cu6Sn5 layer control at the copper interface. A claim-by-claim comparison of that cluster would show exactly how much room remains for new dopant or layer-sequencing approaches.
Explore claim charts in EurekaTrack the co-assignee network over time
The strongest co-filing pairs suggest active joint development agreements. Watching whether these pairs keep filing jointly, or split, is an early signal of where the next wave of alloy IP will originate.
Monitor assignee activity in EurekaCommon questions about solder alloy patents
The dataset shows filings peaking at 231 in 2018 and falling to 102 by 2022, well before any publication-lag effect would explain a drop. This pattern usually means the core compositional space — lead-free SAC alloys with minor dopants like Ni, Bi or Co — had already been claimed heavily by the mid-2010s, leaving later filers with narrower room to differentiate. It does not mean the underlying technology stopped mattering; joint reliability and thermal fatigue remain active manufacturing concerns, but the patenting activity around alloy composition itself has cooled.
Several established solder-industry and electronics manufacturers appear repeatedly in this dataset's co-assignee pairs, including joint filings between major Japanese solder material suppliers and electronics makers. Rather than one dominant single filer, the picture is a cluster of long-standing incumbents who show flat or declining year-over-year filing counts in the most recent tracked year, consistent with a field where the core claim positions are already established and being maintained rather than expanded.
B23K covers welding, soldering and brazing — so it captures process claims: how the joint is formed, reflow profiles, fluxing and wetting behaviour. C22C covers alloys, capturing the compositional claims — the specific ratios of Sn, Ag, Cu, Ni and other elements in the solder itself. In this dataset, B23K appears in 3,371 of 3,832 families and C22C in 2,193, meaning most patents claim the joining process, and a large subset additionally or separately claim the alloy composition. A freedom-to-operate review needs to check both classes, since a product can infringe a process claim even with a novel alloy.
This filing from NIPPON MICROMETAL CORPORATION claims a lead-free Sn-Ag-Cu solder alloy with a narrow compositional window (roughly 1.0-2.0% Ag, 0.3-1.0% Cu, 0.005-0.1% Ni by mass) and, critically, a specific interfacial structure: a Cu3Sn intermetallic layer forming directly on the copper electrode with a Cu6Sn5 layer forming on top of it. Anyone developing a Ni-doped SAC alloy for solder balls or bumps needs to check whether their composition and resulting interface structure falls inside this claimed window, since it is one of the more specific compositional-plus-structural claims in the corpus.
The IPC composition data shows B32B (layered products and laminates) at only 70 records and C23C (coating and surface deposition) at just 59, both far thinner than the 3,371 in B23K and 2,193 in C22C. That gap suggests claims combining solder joints with layered-laminate structures, or coating-based approaches to improving wetting rather than bulk alloy composition changes, are comparatively under-claimed relative to the core process and composition space. These are narrower niches, but ones where a new entrant is less likely to run into a dense prior-art thicket.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.