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Tag: Semiconductor

  • [Economy] Japan Doesn’t Make the Chips — It Makes the Machines That Make Them, and Leads the World in Patents Too

    The most advanced chips in your phone, your car, and the AI models running in the cloud are usually associated with Taiwan or South Korea — but only a handful of countries can supply the machines that make those chips in the first place. Japan quietly controls this chokepoint in the global semiconductor supply chain, with companies like Tokyo Electron, SCREEN Holdings, and DISCO ranking among the world’s top makers of semiconductor manufacturing equipment. That strength shows up just as clearly in the patent world. Drawing on data from the Japan Patent Office and specialist patent-analytics firms, here’s a look at Japanese equipment makers’ patent trends, what they reveal, and one especially notable patent.

    World-Leading in Both Patent Quantity and Quality

    In the “2025 Patent Asset Scale Ranking for the Semiconductor Equipment Industry,” published by the patent analytics firm Patent Result, Tokyo Electron ranked first in the world with 814 registered patents and a score of 22,256.5 points. Applied Materials of the US came in second (586 patents, 18,413.5 points), and SCREEN Holdings placed third (329 patents, 7,836.9 points). This “patent asset scale” isn’t a simple count of filings — it’s calculated by multiplying each patent’s prominence (such as how often it’s cited) by its remaining term, so it measures not just volume but how many genuinely impactful patents a company holds.

    Even more interesting is the 2024 “Blocking Power Ranking.” This tallies how many times a company’s patents were actually cited by examiners as prior art when rejecting other companies’ applications. Here too, Tokyo Electron topped the list with 937 citations, followed by SCREEN Holdings (428), Applied Materials (347), DISCO (277), and ULVAC (154) — Japanese companies took four of the top five spots. The more often a rival’s new invention gets bounced back with, in effect, “we already patented that,” the more that company’s technology has become foundational to the industry.

    Ranking (Year)1st2nd3rd
    Patent Asset Scale (2025)Tokyo ElectronApplied MaterialsSCREEN HD
    Blocking Power (2024)Tokyo ElectronSCREEN HDApplied Materials
    Bar chart comparing Tokyo Electron, Applied Materials, and SCREEN Holdings on 2025 Patent Asset Scale points and 2024 Blocking Power citation counts
    Source: Patent Result, 2025 Patent Asset Scale Ranking and 2024 Blocking Power Ranking (semiconductor equipment industry)

    Three Things the Patent Data Reveals

    1. Citation counts matter more than filing volume as a measure of real strength.
    In a field like semiconductor equipment, where technology builds cumulatively, foundational inventions with broad applicability tend to get cited again and again as grounds for rejecting later filings. Tokyo Electron topping both rankings isn’t just about filing a lot of patents — it’s evidence the company holds foundational technology that rivals simply can’t route around.

    2. Strength is concentrated in front-end processes (deposition, etching, cleaning).
    Looking at the substance of the top-ranked patents, most cluster around “front-end” technologies that work directly on the wafer — deposition, etching, and cleaning. As chips keep shrinking, the value of nanometer-precision processing and cleaning technology keeps rising, so depth of patents in this area translates directly into competitiveness.

    3. These companies have been filing with a global market in mind from the start.
    According to Tokyo Electron’s own disclosures, the company has maintained a global patent filing rate — the share of patents also filed overseas — of roughly 75% for six consecutive years. Securing rights simultaneously not just in Japan but in the major chipmaking countries and regions (the US, China, South Korea, Taiwan) reflects a filing strategy that tracks the company’s global market share.

    One Standout Patent: A Cleaning-Equipment Patent That’s the Industry’s Biggest “Wall”

    A patent’s value isn’t just about how many there are — it’s also about how much it blocks competitors from filing around it. A good example is Tokyo Electron’s patent covering technology that cleans a wafer’s front surface, its beveled edge (the angled cut at the rim), and its back surface all in a single cleaning tool. According to Patent Result’s 2024 survey, this patent was cited more often than any other as grounds for rejection in competitors’ patent examinations — meaning rival makers’ new cleaning-technology filings have repeatedly run into this one idea.

    Cleaning may sound like an unglamorous step, but a semiconductor becomes defective the moment a single invisible speck of dust lands on it. The idea of efficiently cleaning three differently shaped surfaces — front, back, and edge — in one machine is a foundational technology whose value only grows as miniaturization advances. It’s a good example of an unflashy technology that quietly props up the industry from behind the scenes.

    The Bottom Line

    Behind the flashy headlines about semiconductors themselves, the Japanese companies that build the machines that make them maintain a world-class presence in patents, both in quantity and quality. As demand for AI and leading-edge logic chips keeps growing, the patent competition around front-end technologies like deposition, etching, and cleaning looks set to intensify further.

    Patent Result, “2025 Patent Asset Scale Ranking for the Semiconductor Equipment Industry: Top 3 Are Tokyo Electron, AMAT, and SCREEN”
    Patent Result, “2024 Blocking Power Ranking for the Semiconductor Equipment Industry: Top 3 Are Tokyo Electron, SCREEN, and AMAT”
    Tokyo Electron, “Intellectual Property and Intangible Assets”

  • [Science] Beyond Copper: The Battle Over Next-Generation Chip Interconnects

    Inside every semiconductor chip, transistors are wired together by interconnects thinner than one ten-thousandth the width of a human hair. Copper (Cu) has been the workhorse material for these wires for decades, but it is now running into a physical wall as chips keep shrinking. At the VLSI Symposium, an international conference held in Kyoto in June 2025, Tokyo Electron and imec, the Belgium-based research institute, jointly presented new research into what could replace copper in future chips. Their presentation offers a window into where interconnect technology is headed next.

    Why copper wiring is nearing its limit

    Copper has long been the default choice for on-chip wiring because it conducts electricity well and is relatively easy to process. But once wire widths shrink to around 40 nanometers (nm; one nanometer is one-billionth of a meter) or below, copper’s resistance actually starts to rise rather than fall. As wires get thinner, electrons collide more often with the wire’s surface and with the boundaries between metal grains, making it harder for current to flow smoothly. Higher resistance means slower signals and higher power consumption. Since further miniaturization is inevitable, finding a replacement for copper has become a shared challenge across the industry.

    The presentation: ruthenium and semi-damascene wiring

    The joint presentation by Tokyo Electron and imec at VLSI 2025 was titled “Selective Deposition and Ruthenium Superfill for A10-and-Beyond Interconnects.” Ruthenium (Ru) is drawing attention as a metal whose resistance rises more gradually than copper’s as wires get thinner.

    The key idea is a fabrication approach called “semi-damascene.” Conventional copper wiring has relied mainly on the “damascene” process: a trench is etched into the insulating layer first, then filled with metal, and the surface is polished flat. Semi-damascene works differently. A metal film is first deposited across the entire wiring layer, and the unwanted portions are then removed by etching to directly carve out the wiring pattern, skipping the trench-and-fill step altogether. This makes it easier to build the finer, more three-dimensional wiring structures that future chips will need. The new presentation outlined a technical path for depositing ruthenium evenly, even into the narrowest gaps, when this process is used, a property known as “superfill.”

    Why this matters

    In AI chips packed densely with computing circuits, power loss and signal delay in the interconnects can limit the performance of the entire chip. The fact that Tokyo Electron, an equipment maker, is co-developing the interconnect process itself with imec, a materials research hub, signals something important: the practical realization of next-generation interconnects is no longer just about sourcing the right material, it has become a contest over deposition and processing equipment technology.

    AI computation depends on huge numbers of transistors exchanging large amounts of data. Even if transistors get faster, high wire resistance delays signals and increases heat and power use. Interconnects are like the roads of a chip, and their quality helps determine overall performance. That is why the search for a copper replacement is as important to semiconductor progress as transistor scaling itself.

    Why ruthenium looks promising

    As an interconnect material, copper becomes less attractive the thinner it gets. In a talk at IEDM 2020 (summarized in a series by EE Times Japan), imec compared the resistance of vias, the vertical connections between wiring layers. Taking a 14 nm copper via with a 2 nm barrier layer as the reference value of 1, a 10 nm copper via comes to 2.16, more than double, while ruthenium was calculated at 0.59 at 14 nm without a barrier layer. These are calculated comparisons that assume particular dimensions and structures, not direct measurements of actual products. Ruthenium is valued because its resistance is low, it does not need the barrier layer (a thin film that stops copper from diffusing into surrounding insulation) that copper requires, and it can be shaped by etching.

    Conceptual chart: copper resistance rises steeply as wires thin while ruthenium rises gently
    Conceptual schematic: not measured data. Crossover guide per Semiconductor Engineering (2022).

    imec’s 16 nm-pitch ruthenium lines

    On June 3, 2025, imec reported, in a presentation at the IITC 2025 conference, ruthenium lines at 16 nm pitch made with a semi-damascene process. The average resistance was 656 ohms per micrometer, and 40% of the 16 nm-pitch structures met the target resistance predicted from thin-film resistivity (corresponding to 8 nm-wide local wiring). At 18 to 22 nm pitch, full-wafer yield of more than 90% was reported. The work targets the first local wiring layer (M0) of logic chips from the A7 generation onward. This was a different conference from the VLSI Symposium presentation by Tokyo Electron and imec described above.

    Hurdles before real-world use

    Even in imec’s report, only 40% of structures at 16 nm pitch met the target resistance, and yields above 90% were obtained in the 18 to 22 nm pitch range. Remaining issues include optimizing the patterning of ruthenium and suppressing changes in its shape caused by heat. Replacing copper with ruthenium is still at the research stage.

    Table of candidate interconnect materials: copper, ruthenium, molybdenum and cobalt
    Candidate materials and their roles (compiled by Xsciens from Gall 2016 and Semiconductor Engineering 2022).

    Xsciens Editorial Note

    “Copper to ruthenium” is not a done deal; it is a research question about where copper’s limit sits and which materials could take over beyond it.

    • Results versus mass production. What the conference presentations show are research-stage results. Independent work agrees that the direction is plausible: a materials study from Rensselaer Polytechnic Institute (Gall, 2016) found that some metals such as rhodium, iridium and nickel can outperform copper in very narrow wires, while molybdenum, cobalt and ruthenium roughly match it, so ruthenium is one candidate among several.
    • The crossover is a guide, not a line. A commonly cited guide is that ruthenium becomes less resistive than copper below a cross-section of roughly 300 nm² (about 17 × 17 nm), but the exact point depends on barrier thickness, grain structure and process. The figure in this article is a conceptual schematic, not measured data.
    • What to watch next. Etching without damaging the metal (oxidation is a known challenge), uniformity across a whole wafer, cost, and whether cheaper options such as molybdenum take the middle layers while ruthenium takes the thinnest ones.
    • Our imagination (speculation) — We wonder whether this kind of wiring change might eventually let phones and data centers do the same computing with less wasted heat, which could mean longer battery life or lower cooling needs. But a new material also brings new factory processes and costs, so how much of this reaches everyday products is still unknown. This is our speculation, not a forecast.

    References for this note: Gall, “Electron mean free path in elemental metals”, Journal of Applied Physics 119, 085101 (2016) (Rensselaer Polytechnic Institute), Semiconductor Engineering, “How Far Will Copper Interconnects Scale?” (Dec 15, 2022)

    Key terms

    • Pitch: the distance between the centers of neighboring wires
    • Via: a vertical connection between upper and lower wiring layers
    • Barrier layer: a thin film that keeps copper from diffusing into the surrounding insulating film
    • Superfill: deposition that fills even narrow trenches and gaps with metal evenly
    • A10, A7: names for next-generation chip nodes (the letter A stands for the angstrom, one tenth of a nanometer); they do not necessarily indicate an actual physical dimension

    Whether copper will actually be replaced by ruthenium in chip wiring remains a research question, not a settled fact. But tracking what gets presented at international conferences like this one reveals where the next bottlenecks in semiconductor scaling lie, and where equipment makers are looking for solutions. The unglamorous work of wiring a chip is turning out to be one of the front lines that will determine how far AI-era chip performance can go.

    Sources: Tokyo Electron Newsroom, “2025 IEEE Symposium on VLSI Technology and Circuits”, imec, “Semi-damascene metallization: an inflection point in back-end-of-line processing”, imec press release (June 3, 2025), EE Times Japan