The development of EUV resists is one of the major challenges for the deployment of high-NA EUV lithography , which is on the roadmap for high-volume manufacturing of future semiconductor technology nodes. Resist performance is admittedly governed by a resolution-roughness-sensitivity (RLS) tradeoff. This study reports on the EUV resist progress achieved during the last year in the framework of the resist screening program by PSI and ASM L. An extensive performance characterization of different resists was carried out using the XIL-II beamline EUV interference lithography (EUV-IL) tool at the Swiss Light Source (SLS). We present the upgraded screening metrology used in 2020 at PSI enabling increased confidence in results. We report material performance towards patterning lines/spaces features with respect to the key parameters of RLS: half-pitch (HP), dose-to-size (DtS), line-width-roughness (LWR), as well as Z-factor for overall performance consideration. General progress in EUV resist development is reviewed by considering several resist platforms available today from different vendors. Different molecular and chemically amplified resist materials are demonstrated as viable for 16 nm resolution technology nodes. One chemically-amplified resist vendor shows suitable materials for 13-nm-resolution technologies while exhibiting potential for further downscaling. We present different metal-oxide resists screening with resolutions down to 10 nm HP. We finally discuss the overall progress of materials achieved between 2019 and 2020 towards reaching high-NA.

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Three-dimensional imaging using Time-of-flight (ToF) sensors is rapidly gaining widespread adoption in many applications due to their cost effectiveness, simplicity, and compact size. However, the current generation of ToF cameras suffers from low spatial resolution due to physical fabrication limitations. In this paper, we propose CS-ToF, an imaging architecture to achieve high spatial resolution ToF imaging via optical multiplexing and compressive sensing. Our approach is based on the observation that, while depth is non-linearly related to ToF pixel measurements, a phasor representation of captured images results in a linear image formation model. We utilize this property to develop a CS-based technique that is used to recover high resolution 3D images. Based on the proposed architecture, we developed a prototype 1-megapixel compressive ToF camera that achieves as much as 4× improvement in spatial resolution and 3× improvement for natural scenes. We believe that our proposed CS-ToF architecture provides a simple and low-cost solution to improve the spatial resolution of ToF and related sensors.

The introduction of novel photoresists is a critical enabler of future technology nodes, including the upcoming high-NA EUVL deployment. The development of EUV materials is investigated within the scope of a resist screening program between ASML and PSI. In this work, the EUV interference lithography tool at PSI is used to study materials performance in terms of the resolution-roughness-sensitivity tradeoff, with an emphasis on ultimate resolution. Here, we review the development status of different platforms by considering recent results obtained in the first half of 2021 (H1-2021). Patterning resolution of 11 nm half-pitch is achieved with both CAR and non-CAR materials, which indicates steady progress in the global resist development. Perspectives of this work are discussed towards enabling 8 nm half-pitch resolution solutions.

As EUV lithography becomes the new standard for electronic chip manufacturing, identifying suitable materials for higher resolution patterning stands out as a prominent challenge to reach future technology nodes. Innovative approaches to patterning are becoming more and more relevant as conventionally used photoresists approach their limitations. In this work we use the Interference Lithography tool at the Paul Scherrer Institute (Swiss Light Source) for screening of EUV Lithography materials. We highlight the EUV lithography exposure mechanism of secondary electron chemistry and its versatility in inducing a solubility switch in photosensitive materials by using a chicken egg-white albumin protein cluster as a resist to obtain sub-100 nm patterns.