CATBeamTech以碳纳米管X射线技术挑战半导体市场，瞄准HBM缺陷检测

Je-hwang Ryu, CEO of CATBeamTech. (Photo: THE ELEC)

CATBeamTech has expanded its business beyond medical X-ray solutions into the semiconductor industry. Its core technology leverages Carbon Nanotube (CNT)-based X-rays to identify internal defects in High Bandwidth Memory (HBM).

CATBeamTech is currently conducting Proof of Concept (PoC) evaluations for its CNT X-ray equipment with domestic and international memory manufacturers. Upon receiving HBM sample wafers from memory makers, CATBeamTech images cross-sections to inspect for defects at specific locations. During performance verification, potential clients provide a mixed batch of normal and defective samples, and the equipment's performance is evaluated by comparing its classification results against the client's answer key.

HBM features a vertically stacked structure of DRAM chips in 4, 8, 12, or 16 layers. CATBeamTech identifies defects such as micro-bump failures connecting individual DRAM dies, die lifting, and warping.

As the number of stacked layers increases, early inspection becomes critical. Discovering a defect after completing the stacking process results in financial losses that compound across all preceding manufacturing steps. By identifying anomalies mid-process, CATBeamTech helps minimize these losses.

The observed defects are quantified: if the defect count exceeds normal thresholds, the system flags an anomaly for process management. "In the industry, there are rumors that certain memory makers' HBM yield is below 50%," said Je-hwang Ryu, CEO of CATBeamTech. "By tracking defect counts inside HBMs, we can help manage overall yield."

X-ray inspection is a non-destructive semiconductor testing method used to check for internal HBM defects. Through sampling inspection, process errors can be detected and addressed early. The system scans key points on a wafer to evaluate overall alignment and can trigger a secondary, high-precision inspection for suspicious areas. Companies like SEC and Zeiss also produce similar equipment.

CATBeamTech's primary advantage lies in its ability to build fully customized equipment. Parameters such as inspection speed and detectable defect size can be adjusted to client specifications because the company directly manufactures its own equipment, components, and CNT sources.

The equipment can detect defects ranging from 10 to 100 nanometers. According to CEO Ryu, competitors typically observe defects at the 500-nanometer level, giving CATBeamTech a precision advantage of 5 to 50 times. However, smaller defect detection involves a trade-off, such as longer inspection times. For commercialized products, CATBeamTech is developing technology optimized for 100-nanometer-level defect detection, balancing speed and resolution.

X-ray inspection works by transmitting electron-generated X-rays through the target object to observe its internal structure. CATBeamTech utilizes carbon nanotubes (CNTs) as its electron emitters. Traditional X-ray devices emit electrons by heating a filament, whereas CNTs emit electrons via an electric field without requiring thermal heating. Compared to filament sources, CNTs offer faster inspection speeds and are easier to miniaturize. They also enable precise output control, varying X-ray power based on the thickness and density of the target material.

With its CNT-based X-ray technology, CATBeamTech was selected by the Ministry of Small and Medium-sized Enterprises and Startups (MSS) as a promising semiconductor startup under the 'Deep-Tech Startup 1000+' project. Selected companies receive funding from the MSS for commercialization and R&D.

Q&A

Q: What is the Deep-Tech Startup Project?

A: It refers to sectors that the Ministry of Small and Medium-sized Enterprises and Startups (MSS) considers deep-tech, which includes semiconductors, defense, and healthcare. We were selected as a deep-tech company in the semiconductor sector, where they provide us with support. It allows us to further refine and systemize various technologies.

Q: Does the government give you money?

A: They give us funding, and they also serve as a bridge. They provide great guidance in terms of networking and connecting us with client companies.

Q: How much money do they give?

A: Around 1 billion KRW. We originally started with medical and component technology, so the industrial side was somewhat unfamiliar and was an area we didn’t know well. The project provided a great opportunity for us to enter this market rapidly.

Q: Were you selected because you already possess deep-tech technology? Or were you selected as one of the candidates to create deep-tech technology?

A: They look at both. Core technological capability is essential, and a company must possess materials or component technology. Furthermore, the derivative directions and applications must fall under deep-tech criteria to be selected.

Q: Could you please provide a brief introduction to your company and its proprietary technology?

A: Our company is a materials, components, and equipment company. For materials, we directly possess Carbon Nanotube (CNT) technology and synthesize CNTs in-house. Using CNTs, applications can extend to displays, X-rays, or even powder forms for other materials companies. However, our initial primary direction was chosen as X-rays.

We also manufacture X-ray components using electrons emitted from the tips of CNTs. Instead of importing X-ray sources, we possess various proprietary platforms. Because of this, just as bathroom, restaurant, and kitchen lightings are all different depending on their application, we can adapt our X-ray sources to fit specific needs—such as what semiconductor feature to look at, how high throughput needs to be, or how small or large of an object we need to observe.

Q: You previously appeared on our interview channel to introduce your CNT source X-ray technology and overall company background—viewers can refer to the link we’ll provide. You’ve used self-manufactured CNT X-ray sources to inspect internal structures and improve yields in sectors like batteries. I hear your recent focus is on HBM?

A: As the AI market grew dramatically, the world became covered in talks about artificial intelligence. With that, the need to look inside the HBMs used within core GPUs has grown significantly. The reason is that low yields are a widely known issue in this market, which also makes memory prices extremely expensive. Memory prices have risen considerably, but looking ahead, chips will be stacked up to 16 layers. If a problem occurs, the whole thing has to be thrown away.

If you build the 1st floor and inspect it, then build the 2nd floor and inspect it, and keep building if there are no issues, it works fine. But if there’s a problem on the 2nd floor and you keep building the 3rd, 4th, and 5th floors, that entire unit has to be discarded. That is why early inspection is currently so necessary.

Q: You compared it to an apartment, where each floor has structural components and plumbing connections. HBM is similar: if micro-bumps are poorly formed, cracked, or voided, electricity won't flow properly and causes failures. Your company's solution can observe this non-destructively, correct?

A: That is correct. Proper stacking means the micro-bumps are in their proper positions. If you look at a cross-section of the bumps using CT, you can count them. If they are misaligned, you won't be able to count the bumps normally in that cross-sectional view. Therefore, if this inspection goes well and allows normal counting across 2, 3, 4, up to 8 layers, the unit is confirmed as good. In short, processing the numerical values measured from images into statistical data—that is the direction our company is taking.

Q: Why do you process it statistically? Isn't it enough to just see if there is a defect?

A: Yes, seeing if there's a problem is the field called inspection. But in our field, metrology, numbers are key. Those numbers are ultimately converted into data linked directly to yield management. Usually, a separate team handles related tasks and manages yield by compiling statistics during device manufacturing.

Q: So inspection is "looking at it," and metrology is "counting it"?

A: Yes, exactly. Because it expresses exactly where and how a problem occurred as a number, it allows for proactive prevention. That difference is why we aim for metrology.

Q: You are a company that uses visual inspection to perform counting technology. One thing I wondered about is: isn't using X-rays to look inside HBM already a widely used technology? Companies like SEC and Zeiss are already in this market. Since everyone uses X-rays, I wondered what your differentiation is. Is it higher resolution, or are there other differences?

A: Obtaining X-ray images, building 3D volume data (CT data), and providing those results are the same. Our strength lies in directly possessing the X-ray source technology itself. It can be compared to a screwdriver: you need to use the exact right tool for the situation to identify problems quickly. This means our key advantage is providing solutions that perfectly match customer customization needs.

Recently, we have also been leveraging Artificial Intelligence (AI) technology to meet customer criteria—shooting images faster, lowering costs, improving visibility, and enhancing our overall customization capabilities. Companies like Zeiss mostly focus on general-purpose equipment. However, our advantage of being based in South Korea allows us to collaborate closely with clients here.

Q: You mentioned that holding the CNT source technology allows you to build equipment in whatever form the customer wants. What specific customer requirements might exist?

A: Even when looking inside HBM, requirements differ. In some cases, they only need to look at micro-bumps, while in others, they need to inspect die lifting or warping. Depending on the case, they might need to use a single X-ray source, five sources, or in extreme cases, around 50 sources. Accurately understanding customer needs and designing matching system structures to deliver solutions is our major point of differentiation from existing companies.

Q: How about speed and maintenance? Regarding lifespan, isn't CNT shorter compared to filaments?

A: Technology has advanced significantly, so lifespans are now at a similar level. Technically, filaments use a heating method, whereas carbon nanotubes can be viewed as digital X-ray sources. Filaments are analog technology, while CNTs are digital. Filaments are bulb technology, whereas CNTs are LED technology. A bulb setup uses only a single source because turning it on and off like digital equipment is difficult, so it stays continuously lit. In contrast, CNT technology can be turned on and off very easily.

Therefore, if multiple sources are required depending on the inspection target, they can be deployed as an array. If a certain area is thick or dense, we can use a stronger X-ray; if density is low, we can use a lower-output X-ray. Offering customized configurations is a massive advantage of CNT.

Q: For example, when getting a CT scan at a hospital, the machine rotates and takes time. Are you saying that instead of rotating the source, you can arrange sources in a circular array to capture images at once?

A: Exactly. X-ray sources used in hospital CT scanners are filaments, meaning there is only one X-ray source inside. Because it generates heat, it requires a cooling system. Then, large power modules called generators are needed.

It also requires high-grade bearings, and when all the mechanical components for maintaining stability are added up, it weighs several tons. When that technology transitions to digital, industrial applications gain the exact same benefits. Our company's starting point was originally to change the paradigm in the medical field, and we are now able to realize those same advantages in industrial fields.

Q: Is it true that your equipment can identify defects down to the 10-nanometer level?

A: We are a company holding technology solutions aimed at reaching the 10-nanometer domain. Competitors' typical specification is around 500nm, or 0.5 micrometers. We possess the core X-ray technology and focal point control technology mentioned earlier. Optical tech is required, and by harmonizing layout, magnification, and vibration control, we can observe down to 10 nanometers.

Q: Are you able to see down to 10 nanometers right now?

A: Yes, although 10 nanometers isn't visible with crystal-clear precision; it ranges between roughly 10 and 100 nanometers. Since other companies are usually around 0.5 microns, we can see much better. There is a market for high-end equipment that maximizes resolution, but equipment used in mass production lines has size limitations. Under those production constraints, 10 nanometers obviously cannot be seen.

Q: How long does it take to inspect a single HBM?

A: It depends on whether it is a 4-layer or 8-layer stack, but inspecting a single point usually takes about 10 to 60 minutes.

Q: What does "a single point" mean?

A: An HBM cross-sectional sample is about 10mm × 10mm in size, and we are looking at one specific point on that sample.

Q: Then clients cannot use this for 100% total inspection; they would use it for sample testing?

A: Correct. If it's a 300mm wafer, it has four quadrants. They can inspect them one by one or two by two to obtain information that represents the overall alignment state.

Q: So it would mainly be used during the development process?

A: Right. Some teams look at it during development, and some look at it at the final stage. I believe it must be used during development to catch yields effectively.

Q: Do you mean they take a rough look first, and if there seems to be a problem, they bring it over to take a precise image of that exact spot?

A: Exactly. The 1st step is a screening inspection, and the 2nd step is a precision inspection. In screening, they might use a fast CT scan or look only with basic X-rays.

Q: If a suspicious area appears under X-ray, do you perform statistical processing on that region?

A: We inspect only the suspicious area. We inspect the representative point, check a certain surrounding area, and then move on to the next process.

Q: Is there high market demand for this?

A: As known in the industry, current (HBM) yields are quite poor. Some companies are rumored to be below 50%. It's not great from a resource efficiency standpoint.

Q: Speaking as a non-expert, wouldn't doing 100% total inspection be more effective for boosting yield? Is total inspection not possible with X-rays?

A: It is possible. However, due to the current AI boom, even if chips are discarded, semiconductor makers' customers have enormous product demand and keep asking for continuous supply. That's why the current ecosystem was formed. But looking ahead at the next 10 years, normal manufacturing processes must include yield management. That way, our great domestic semiconductor makers can maintain their gap over China and latecomers while preparing for the future. We want to contribute with our core analysis and yield management technology.

Q: So you're saying they currently don't do total inspection. Is it because they can't, or because they choose not to?

A: Both. Defects aren't easily visible, and inspecting takes too much time.

Q: But your company's solution isn't a total inspection method either, is it?

A: Right now, we are at the PoC stage—demonstrating the concept and establishing the inspection logic.

Q: What point are prospective clients most interested in? Are they drawn to seeing finer details than others, or is it your proprietary source tech and faster inspection speed?

A: Clients have teams closer to R&D labs and teams closer to production factories. Naturally, R&D teams value precision even if speed is slower, while factory teams say, "It can be less precise, just make it fast." Both needs exist.

Speeding up the inspection makes images slightly less clear or blurry, while spending more time yields clearer images. It's a trade-off.

Q: Who are you currently talking with?

A: We are speaking with all major semiconductor clients, including Korean and US companies.

Q: They must be memory makers. When did discussions regarding HBM begin?

A: We started last year.

Q: How much does a single unit cost?

A: It depends on inspection speed and logistics integration, but prices generally range between 500 million and 3 billion KRW. If it needs to shoot fast while maintaining crisp clarity, it's 3 billion KRW; if it shoots relatively slowly with lower resolution, it's 500 million KRW.

Q: Are PoCs currently underway?

A: Yes.

Q: What does running a PoC entail? Are you receiving wafers and chips to inspect them, or is equipment installed on-site somewhere?

A: Customer requests are like: "We'll give you samples, show us what comes out." They ask for visualization data first.

Q: Do they tell you which specific points to capture?

A: They ask things like: "What can you see?", "Can you count the numbers?", etc.

Q: Can results be improved using AI as well?

A: We need to guide it toward enhancing both inspection precision and speed.

Q: So you receive samples, inspect them, send back the results, and continue that cycle?

A: Yes, we are continuously exchanging data. Inspecting HBM extracted from commercially available GPUs can be freely promoted. What we showed today is a sample from a disassembled Nvidia board we purchased, since client samples cannot be disclosed. Clients ask us questions while already knowing the correct answers.

Q: Meaning if it's a defective sample, the defect should show up?

A: They mix normal samples and defective samples together when handing them to us.

Q: It sounds like solving a puzzle. They evaluate whether you can see it or not?

A: Yes, so they already know the answer.

Q: Do they tell you how many points you got right?

A: Yes, they share the evaluation results with us.

Q: Are you getting 100 points right now?

A: Sometimes we get 50 points, and sometimes we get around 95 points.

Q: Why do the scores vary? Is it because points were captured incorrectly?

A: Sometimes they specify the points, and sometimes they don't. When inspecting at the 10-nanometer scale, there are countless points, so we scan an area of about 20 micrometers within a 100-micrometer field at a resolution capable of resolving 10-nanometer features.

If there's a void, we quickly catch that empty space, or if alignment is bad, we look for areas where bump counting fails. There are various parameters and elements to look at, so we tailor solutions to client requirements.

Q: What score satisfies the customer?

A: Customers unconditionally want 100 points.

Q: Does that mean they aren't satisfied even with 95 points? Why do scores come out at 70 or 90 points?

A: It requires a process. You have to start from 50 to get to 60, and go through 60 to reach 70. No matter how smart we are or how many solutions we have, that process is about getting familiar with customer demands and understanding each other. So even if we hit 50, 60, 70, and eventually 100 points, when they bring another application next time, we can climb the scoring ladder much faster.

Our ultimate target is 100 points. If hitting 100 points makes it impossible to meet speed requirements, we might compromise in the 90-point range.

Q: If it's 100 points, it will obviously be used as a good unit, but whether it scores 90 or 50 points, shouldn't defective units be discarded?

A: They have to be discarded, but the client knows best how much margin they can allow. Having a void doesn't automatically mean the product won't function at all. Looking at the Nvidia B200, the government mentioned acquiring 250,000 units last year. Those cost around 50 million KRW each, with cost of goods sold (COGS) at about 50%. Since eight HBMs are in a B200, dividing 25 million KRW by eight puts one HBM at roughly 3 million KRW.

Q: People don't usually calculate it quite like that, though.

A: Yes, it's a simplified calculation. If an 8-layer stack goes in, we used to buy individual DRAMs for PC memory for 50,000 KRW each. Though it's a different memory type, an 8-layer DRAM stack would technically be a lower-cost item on its own. But when packaged as an HBM unit, it comes to around 3 million KRW. Clients can simply calculate that discarding some units still leaves high profit margins.

Q: You are currently receiving chips, sending back data, and getting scored. When do you expect this to generate actual revenue?

A: I believe that even at 80 to 90 points, clients will adopt it and adjust it internally for application. Actual line deployment might differ.

Q: Are they not using it currently?

A: They do use inspection, but our equipment offers better resolution. That is where our competitive edge lies.

Q: Is it because you build customized systems tailored to their concepts?

A: Yes. They don't reveal exact details, but judging by their reactions, follow-up projects continue. That indicates a relationship we can build upon.

Q: If this leads to actual adoption, how many units could you sell?

A: Selling one unit leads to selling two, and once the client feels confident, they could purchase up to 50 units.

Q: When investors ask if things are going well, what do you tell them?

A: We tell them that we are actively exchanging data with current HBM clients.

Q: When do you tell investors revenue will materialize?

A: Working hard on HBM inspection has created derivative technologies and spin-off products, which are already generating revenue.

Q: What are those specifically?

A: Components that go into semiconductor manufacturing equipment, such as valves. Since these components also require non-destructive testing, we built and sold inspection equipment for gas nozzles and CVD equipment parts. To investors, we explain that while HBM inspection is our pinnacle goal, we have created intermediate step-by-step product milestones along the way.

Q: CEO Ryu, once you achieve clear revenue results, please visit us again to share the news.

A: Please invite me anytime. Two years ago we discussed batteries, last year we discussed carbon nanotube materials, and now we aim to become a company specialized in HBM inspection.

I’d like to leave one final thought: the battery and display markets have largely shifted toward China, where competition is intensifying. In contrast, South Korea holds a dominant position in the HBM market. To protect this leadership, yield inspection technology is vital. Proper yield inspection will allow Korean semiconductor makers to maintain their gap over Chinese competitors for a long time. We want to contribute to that effort with our core analysis and yield management technologies.