The interaction of extreme ultraviolet (EUV) light with matter is a critical step in EUV lithographic processes, and optimization of the optical material properties of all elements in the lithographic chain (from optical coatings and pellicles to photoresists) is crucial to harnessing the full power of EUV lithography. To optimize these materials, accurate measurements of EUV absorption and reflection are needed to extract the corresponding actinic optical properties and structural parameters. Here, we report on actinic EUV metrology-based absorption and reflection measurements enabled by coherent table-top EUV sources based on high-harmonic generation. We demonstrate the capabilities and flexibility of our setup with measurements on crystalline films, photoresist systems, and carbon nanotube membranes and provide extracted optical parameters, absorption kinetics, and 2D transmission maps, respectively. These results showcase the power of lab-based actinic inspection methods based on compact, coherent EUV sources for providing crucial data for material optimization and lithographic simulation.
In the manufacturing of CMOS devices, the golden standard for determining yield at various stages of production is electrical testing. This allows for the identification of failing devices or early yield failures before proceeding to subsequent steps. However, the failure of electrical tests can occur due to various reasons inherent to the structures of the devices. Additionally, a comprehensive analysis is necessary to ascertain the root cause of the failure mechanism once a device does not pass the electrical tests.
The interaction of EUV light with matter is a critical step in EUV lithographic processes and optimization of the optical material parameters of photoresists and reflector/absorber stacks is crucial to harness the full power of EUV lithography. To optimize these materials, accurate measurements of EUV absorption and reflection are needed to extract the corresponding actinic optical properties and structural parameters. Here, we report on two endstations within imec’s AttoLab that enable actinic EUV absorption and reflection measurements. We commission these tools with measurements on model thin film and photoresist systems and provide extracted optical parameters as well as absorption kinetics, respectively. These results showcase the power of these tools for providing crucial data for material optimization and lithographic simulation.
The continuous need to shrink dimensions using EUV lithography has posed challenges and opportunities for patterning materials and processes. Scaling BEOL interconnect structured is a key element to performance improvement of functional devices. In this paper, we investigate the impact of various factors on the patterning of EUV single exposure vias, to find effective strategies to shrink critical dimension (CD) with improved critical dimension uniformity (CDU), local critical dimension uniformity (LCDU) and decrease in defectivity. This work is based on patterning a system on chip (SoC) random logic via layer at minimum horizontal interconnect wire pitch of 28nm, which is the limit of single exposure interconnect with 0.33 NA EUV tools. This design uses aggressive CPP/Mx gear ratio of 3/2 which is equivalent to 38nm to 34nm pitch orthogonal via arrays, thus, examining the impact of the primary patterning parameter and illumination source co-optimized with OPC treatment of rectangular vias. The via patterns are transferred to bottom dielectrics to study the evolution of LCDU and defectivity through etch.
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