Photoresist Strip & Wafer Cleaning Patents: Leaders & Trends 2026
- Filing has plateaued, not grown. The midpoint year (2022) sat at 7 families and the peak came only in 2024 at 12 — a flat-to-declining curve, not a boom.
- Megasonic cleaning claims dominate the citation graph. The five most-cited records in this corpus are almost all megasonic or wet-cleaning system patents, some dating back to the 1990s, still shaping freedom-to-operate today.
- Chemistry claims are the thin slice. C11D (detergents & cleaning compositions) accounts for only 20 of 217 records against 155 in H01L and 149 in B08B — most of the claim space is equipment and process, not formulation.
Filing growth compares 2021 (3 records) with 2024 (12) — 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 217 records in scope (CR5), not by the ranked leaders only.
What this patent set covers
Photoresist strip and wafer cleaning sits at the intersection of semiconductor device fabrication (H01L21) and general cleaning engineering (B08B3, C11D7). The search pulls records that combine process language — particle removal efficiency, megasonic cleaning, watermark control, chemistry consumption — with these classification codes, isolating the wet-clean and dry-strip steps that sit between etch and the next deposition or implant.
Two hundred and seventeen families span 2015 through the partial 2026 year, filed through the USPTO, CNIPA, WIPO, EPO, KIPO and JPO in that order of volume. The technology composition leans heavily toward equipment and system claims rather than chemical formulation, which shapes where the open claim territory actually sits.
Filing trend and technology mix
Publication counts understate the most recent one to two years because of the typical 18-month lag between filing and publication; treat the tail of any trend chart as a floor, not a ceiling.
A flat curve with one late peak
Filings were effectively zero in 2017, climbed toward a midpoint of 7 families in 2022, and peaked at 12 in 2024 — the most recent complete year on record. That shape reads as a mature, incrementally-filed field rather than one attracting a new wave of entrants.
Equipment and process outweigh chemistry
H01L (155 records) and B08B (149) dominate the classification mix, with H10P appearing in 133 — together pointing to system, tool and integration claims. C11D, the detergent/cleaning-composition class, carries only 20 records, and B06B (mechanical vibration generation, relevant to megasonic/ultrasonic cleaning) sits at 14. B24B (grinding/polishing) and C23G (metal surface cleaning) are the smallest slices at 5 each.
Shares are the percentage of the 217 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Photoresist Strip and Wafer Cleaning with Eureka
This page is one run against one query. Ask Eureka your own question about photoresist strip and wafer cleaning and every answer comes back with the patent numbers behind it.
Try EurekaThe records everyone in this field cites
Fast single-article megasonic cleaning process for single-sided or dual-sided cleaning
A fast single-article megasonic cleaning system is used to clean substrates such as semiconductor wafers and flat panel display glass at frequencies of 400 kHz to 20,000 kHz or higher. The technique delivers a single-wafer cleaning process that cuts cleaning time from the 10-20 minutes typical of earlier systems to 15-60 seconds by concentrating megasonic energy on one wafer via a transducer, or a pair of transducers, positioned parallel to the substrate and covering more than roughly 40% of the substrate area.Filed by Busnaina, Ahmed A. — published 2001-08-16.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5656097A | Semiconductor wafer cleaning system | 274 |
| 2 | US6039059A | Wafer cleaning system | 189 |
| 3 | US20020029788A1 | Method and apparatus for wafer cleaning | 162 |
| 4 | US20090130849A1 | Chemical mechanical polishing and wafer cleaning composition comprising amidoxime compounds and associated me… | 156 |
| 5 | US5800626A | Control of gas content in process liquids for improved megasonic cleaning of semiconductor wafers and microel… | 150 |
| 6 | US20030083214A1 | Semiconductor wafer cleaning agent and cleaning method | 109 |
| 7 | US5908509A | Semiconductor wafer cleaning system | 106 |
| 8 | US5520205A | Apparatus for wafer cleaning with rotation | 92 |
| 9 | US5980647A | Metal removal cleaning process and apparatus | 81 |
| 10 | US6070284A | Wafer cleaning method and system | 79 |
Citation counts favour older filings simply because they have had longer to accumulate references within a searched corpus; treat this table as a map of foundational claims, not of current market importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three read-throughs matter for anyone deciding where to file or where to license in this space.
The field peaked recently but is not accelerating
Filings rose from near zero in 2017 to a midpoint of 7 in 2022 and a peak of 12 in 2024. That is growth, but slow growth relative to a 217-family total spread across eleven years — this is an incrementally-refreshed field, not one seeing a surge of new capital or new entrants.
Chemistry claims are the underweight branch
Detergent and cleaning-composition claims (C11D7) make up less than a tenth of the corpus against 155 H01L and 149 B08B records. Most protected ground is equipment design, process sequencing and system integration rather than the cleaning chemistry itself.
Old megasonic system patents still anchor freedom-to-operate
The most-cited record in the set, a semiconductor wafer cleaning system patent, carries 274 citations, and three of the top five most-cited records are megasonic or wet-clean system claims. New filers in single-wafer or megasonic cleaning should check against this older core before assuming clear ground.
A small inventor cluster drives the megasonic sub-area
Only 10 co-assignee pairs appear in the whole set, and the strongest pairing — Verhaverbeke Steven with Truman J Kelly — recurs at 13 shared filings, with two further pairings involving the same lead inventor at 11 each. Megasonic cleaning IP here traces back to a tight, identifiable group rather than a broad industry base.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to photoresist strip and wafer cleaning, with the prior art for and against each one.
Who holds the ground
Recent-year momentum across the leading assignees is flat: every name tracked in the latest-year momentum view shows zero filings in the most recent year, consistent with the overall plateau in the trend chart and with publication lag masking filings still working through the pipeline.
Large tool makers hold historical volume, not recent momentum
Assignees with the deepest historical filing counts in this set — spanning materials and equipment suppliers, foundries and diversified electronics manufacturers — show no filings in the latest tracked year, though this likely reflects publication lag as much as a real pullback.
A named inventor group anchors the megasonic sub-field
Steven Verhaverbeke appears across the strongest co-assignee pairings in the dataset, alongside Truman J Kelly, Alexander Ko and Rick R Endo. This points to a durable, individually-attributable body of megasonic and single-wafer cleaning claims rather than one filed under a single corporate umbrella.
Filing is US-centred with a rising China share
The United States receives the largest share of filings at 106, with China second at 39 and WIPO PCT filings at 19. Europe, South Korea and Japan trail behind, suggesting most applicants still treat the US as the primary jurisdiction for this technology before extending coverage elsewhere.
| Assignee | Recent year | YoY |
|---|---|---|
| Applied Materials, Inc. | 0 | — |
| VERTEQ INC | 0 | — |
| Hangzhou Zhongxi Electronic Technology Co., Ltd. | 0 | — |
| Taiwan Semiconductor Manufacturing Company (TSMC) | 0 | — |
| International Business Machines Corporation (IBM) | 0 | — |
| VERHAVERBEKE STEVEN | 0 | — |
| TRUMAN J KELLY | 0 | — |
| KO ALEXANDER | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether you are filing, licensing or clearing a design.
Map your process step against the classification mix
If your work sits in cleaning chemistry rather than equipment, you are filing into the thinnest slice of this corpus (20 C11D records) — a search that starts from the composition angle rather than the system angle will surface different prior art.
Explore the IPC breakdownCheck freedom-to-operate against the oldest, most-cited records
The top-cited megasonic and wet-clean system patents in this set predate most current filings by two decades and still anchor the citation graph; any single-wafer or megasonic cleaning claim should be checked against them first.
Review the key patents tableWatch the Verhaverbeke co-filing cluster
A small, named inventor group holds the densest co-assignee pairings in megasonic cleaning; tracking their continuation filings is a more targeted signal than watching corporate assignees alone.
See collaboration patternsCommon questions about this patent landscape
The corpus shows a mix of large equipment and materials suppliers, a major foundry, and a diversified electronics manufacturer holding the bulk of historical filings, alongside a distinct cluster of megasonic cleaning patents tied to named inventors including Steven Verhaverbeke. No single assignee dominates outright; filing counts are spread across roughly 217 families with the largest holders each accounting for a modest share. Anyone doing competitive tracking should watch both the corporate assignees and the independent inventor cluster separately, since their filing behaviour differs.
Filing activity in this dataset is flat to slightly rising rather than growing quickly: the midpoint year 2022 recorded 7 families, and the peak so far, in 2024, reached only 12. Given the roughly 18-month lag between filing and publication, the most recent one to two years are undercounted in any raw trend chart, but even accounting for that lag the overall shape is a mature field with incremental rather than accelerating output. This matters for licensing strategy: it is not a space where a wave of new entrants is currently crowding in.
Megasonic cleaning uses high-frequency acoustic energy, typically in the hundreds of kHz to low MHz range, to dislodge particles from a wafer surface without the mechanical damage risk of lower-frequency ultrasonic methods. It shows up heavily in this dataset because several of the most-cited records in the corpus, some dating to the 1990s, are megasonic cleaning system patents, and the B06B classification (generating mechanical vibrations) is well represented alongside the core B08B cleaning class. Later filings in single-wafer and dual-sided megasonic cleaning, including the featured representative record here, build directly on that earlier system-level IP.
The classification mix points to cleaning chemistry, watermark-free rinse sequencing, and metal-surface cleaning integration as comparatively thin branches: C11D chemistry records total only 20 against 155 H01L and 149 B08B records, and C23G metal-surface cleaning sits at just 5. These are areas where the equipment and system-level claim space is already dense but the formulation and integration angles are less thoroughly claimed, making them a more promising starting point for a new filing than the crowded core system classes.
Age alone does not remove a patent from consideration for freedom-to-operate purposes if it is still in force in relevant jurisdictions, and even after expiry its claims define prior art that later filings must design around. US5656097A, the most-cited record in this corpus at 274 citations, along with several other 1990s-era wafer cleaning system patents, still shapes how later megasonic and single-wafer cleaning claims are drafted, because so much subsequent work cites back to that system-level architecture. Any new filer in single-wafer wet cleaning should check current legal status and claim scope of these anchor patents rather than assume they are moot simply because they are old.
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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.