Paul van Gerven
12 February

ASML’s and Imec’s joint High-NA Lab in Veldhoven is about to open its doors to chipmakers, kicking off the next stage in high-NA development: getting the process technology and associated infrastructure ready.

Chipmakers will soon be able to try their hand at high-NA EUV lithography. As the assembly of the world’s first fully functioning high-NA tool nears completion, the High-NA Lab in Veldhoven will be ready to receive customers in Q1, ASML’s head of high-NA product development Greet Storms told reporters on Friday.

Offering access as soon as the first new-generation tool becomes available is a lesson learned from the previous lithography transition, Storms said. Precious time is saved by putting the EXE:5000 pre-production system to work in Veldhoven as soon as it’s completed, instead of shipping it to long-standing partner Imec in Leuven, which usually would be the first to receive next-gen lithography equipment. All in all, this strategy will save about a year.

The High-NA Lab is run jointly by ASML and Imec. It will partly function as a shared-learning facility to develop high-NA process technology (per Imec’s usual formula) and will partly allow ASML’s customers private access to the tool. In addition to the ability to expose and develop wafers, there’s an assortment of metrology tools available on-site. For more elaborate experiments, wafers can be sent to the home base or nearby Imec for further processing and measurement.

Top secret

Although the completion of the high-NA tool, the most complex piece of machinery ever made, marks an essential step to continue scaling of chip features, several hurdles remain before the technology is ready for prime time. Resist, reticles and metrology tools need to evolve to be able to create sharp prints with smaller details than ever.

ASML special

One key challenge is controlling defects and line-edge roughness, which occur as a result of statistical fluctuations in the way photons hit the wafer. As chip structures get smaller, it becomes progressively difficult to keep such so-called stochastic effects in check.

Additionally, increasing the numerical aperture (NA) – high-NA moves to an NA of 0.55, up from 0.33 – decreases the available depth of field, meaning that projected features are in acceptably sharp focus in a smaller ‘band’ than chipmakers are accustomed to. This necessitates the use of thinner resist layers, which capture fewer photons, thus exacerbating stochastic effects.

After simulations and approximation experiments using low-NA EUV tools, the High-NA Lab offers the first opportunity to start tackling this and other critical issues in real life. Chipmakers will be happy to get a head start on formulating their top-secret high-NA chipmaking recipes as well.

ASML high NA cleanroom Veldhoven 025
High-NA tools are assembled from fully formed and validated modules. Here, the reticle stage module is moved into position. Credit: ASML

Confidence

In another move demonstrating the expedited roll-out of high-NA, ASML recently started shipping an EXE:5000 system to Intel, so even before the first prototype is fully up and running. This approach is enabled by a radically modular design, which allows for all eight modules that come together to form the bus-sized tool to be fully tested and validated in isolation. During a tour of its high-NA manufacturing facilities, ASML showed journalists several of such modules being poked and prodded in preparation for additional shipments later this or next year.

Contrary to recent speculation in the media, ASML won’t ship ten high-NA tools this year. A spokesperson said it will be “a number” of them in 2024, understood to mean less than a handful. The equipment manufacturer has racked up a double-digit number of orders so far, at least one system from every logic and memory maker already using EUV, plus Rapidus, Japan’s aspiring leading-edge foundry.

There’s some uncertainty surrounding the insertion of high-NA into mass production. Although Intel is going full steam ahead, TSMC and possibly Samsung are reported to take a more cautious approach. ASML denies the lukewarm reception, calling high-NA “clearly the most cost-effective solution”. Greet Storms said the industry would see large-scale adoption in the 2026/2027 time frame.

Underlining its confidence, ASML has recently demolished office space at its headquarters to make room for additional high-NA manufacturing facilities. The firm is planning to ship 20 high-NA tools per year by 2028.

Main picture credit: ASML