Although EUV masks have been available for engineering development for many years, countless inventions and innovations have been required to make “HVM EUV masks” at the quality and scale necessary to enable EUVL lithography, thus driving the whole semiconductor industry to the sub-5-nm regime. Lithographic patterning using EUV light at 13.5 nm has enabled the industry to forge a new path in which finer resolution geometries can be patterned more quickly and more efficiently on wafer, enabling a new wave of complex chip designs supporting the new era of artificial intelligence computing.

Innovations spanning the mask industry and tireless engineering have matured EUV mask making from concept and feasibility to a full HVM production quality over the past two to three decades. In this special section, we will explore current and future EUV mask-making challenges, solutions, and opportunities. As many of these topics have been addressed in recent years, this special section will provide a review of key technical topics and solutions. This is therefore a unique opportunity to share ongoing and recent experimental work to enable the new EUV patterning paradigm. Potential topics include but are not limited to:

• EUV blank manufacture, inspection, and qualification for current and future HiNa EUV masks
• EUV mask pellicle technology, including novel mounting and membrane related technology, CNT films, stabilization techniques, and characterization.
• Key innovations in EUV masks, resists, and deposition of key materials
• E-beam writer advancements
• Reticle inspection solutions in the mask shop and the fab, with and without pellicles
• EUV mask cleaning and repair techniques.
• Repair verification methodologies and equipment
• Key metrology systems focused on EUV masks
• Software in of support data manipulations and corrections in OPC and the mask fabrication process
• Physical handling challenges of EUV masks at the mask shop, the wafer fab, and in the scanner.

All papers will undergo the standard peer-review process for the Journal of Micro/Nanopatterning, Materials, and Metrology (JM ³). Manuscripts should be submitted to SPIE according to the journal guidelines at http://spie.org/jm3. A cover letter indicating that the submission is intended for this special section should be included. For more information, please contact the guest editor or jm3@spie.org.

High numerical aperture (NA) scanners allow continued extension of Moore’s law at 13.5 nm wavelength and come with various technical and economic challenges. In this special section, we explore the current and future challenges of high NA scanners at 2 nm node and beyond. As many of these topics have been addressed in some form over the past several years, in this special section we will bring a review of key technical topics. At this moment, the integration of the 0.55 NA system is in full progress. Therefore, this is also a unique opportunity to share early experimental work. Potential topics include but are not limited to:

• High NA tool overview including light source
• High NA optics, manufacturing challenges
• Anamorph imaging in high NA lithography, stitching
• Computational imaging aspects of high NA imaging
• Overlay optimization using half field exposure tool
• High NA resists – managing stochastics, high resolution, and low thickness.
• High NA patterning challenges and double patterning
• High NA metrology challenges
• High NA mask writing, mask choices, and new materials
• Metrology aspects of high NA imaging.

All papers will undergo the standard peer-review process for the Journal of Micro/Nanopatterning, Materials, and Metrology (JM³). Manuscripts should be submitted to SPIE according to the journal guidelines at http://spie.org/jm3. A cover letter indicating that the submission is intended for this special section should be included. For more information, please contact the guest editor or jm3@spie.org.

As the adoption of extreme ultraviolet (EUV) lithography in high volume manufacturing continues to expand and EUV nodes continue to shrink, the application of at-wavelength metrology, inspection, and characterization is becoming increasingly critical. Several factors drive the importance of at-wavelength metrology techniques in the EUV regime, but first and foremost on the list is the fact that EUV lithography relies on the use of highly specialized Bragg coatings (multilayers). Such structures are highly chromatic by design and can only be fully characterized at the design wavelength. This fact is particularly critical in all applications related to metrology, inspection, and characterization of the mask.

Another important characteristic of EUV light is that at a photon energy of 92 eV, EUV photons are significantly more energetic than typical binding energies. The relevance of this is that EUV-induced radiation chemistry can differ significantly compared to deep UV and/or electron-induced chemistry. This is important both from the radiation damage perspective as well as from the EUV resist chemistry perspective. Understanding these effects requires the use of at-wavelength characterization tools.

Finally, from the perspective of wafer metrology, utilizing the shorter wavelengths in the EUV and soft-x-ray regime provides important resolution margin compared to DUV metrology solutions. Moreover, the chemical sensitivity in this wavelength regime provides a mechanism to measure molecular states of buried interfaces which opens up new possibilities in device characterization.

This JM³ special section will highlight challenges and solutions unique to EUV and soft-x-ray metrology, inspection, and characterization. Please submit a technology review, consolidation of existing learning, or original technical paper related to this field. Potential topics could include but are not limited to:

• EUV mask inspection (patterned and blank)
• EUV mask defect review
• EUV/soft-x-ray metrology light sources
• EUV mask and patterning materials characterization
• EUV/soft-x-ray wafer metrology
• EUV radiometry

All papers will undergo the standard peer-review process for the Journal of Micro/Nanopatterning, Materials, and Metrology (JM³). Manuscripts should be submitted to SPIE according to the journal guidelines at http://spie.org/jm3. A cover letter indicating that the submission is intended for this special section should be included. For more information, please contact the guest editor or jm3@spie.org.