EUV mirror interference lithography

Researchers from the Paul Scherrer Institute developed an EUV lithography technique that can produce conductive tracks with a separation of just five nanometers by exposing the sample indirectly rather than directly.

Called EUV mirror interference lithography (MIL), the technique uses two mutually coherent beams that are reflected onto the wafer by two identical mirrors. The beams then create an interference pattern whose period depends on both the angle of incidence and the wavelength of the light. In addition to the 5nm resolution, the conductive tracks were found to have high contrast and sharp edges.

“Our results show that EUV lithography can produce extremely high resolutions, indicating that there are no fundamental limitations yet. This is really exciting since it extends the horizon of what we deem as possible and can also open up new avenues for research in the field of EUV lithography and photoresist materials,” said Dimitrios Kazazis of the Laboratory of X-ray Nanoscience and Technologies at PSI in a statement.

The method is currently too slow for industrial chip production and can produce only simple and periodic structures. However, the team sees it as a resource for early development of new photoresists and plans to continue research to improve its performance and capabilities. [1]

Artificial sapphire dielectrics

Researchers from Shanghai Institute of Microsystem and Information Technology created artificial sapphire dielectric wafers made of single-crystalline aluminum oxide (Al₂O₃).

“The aluminum oxide we created is essentially artificial sapphire, identical to natural sapphire in terms of crystal structure, dielectric properties and insulation characteristics,” said Tian Zi’ao, a researcher at SIMIT, in a release.

“By using intercalation oxidation technology on single-crystal aluminum, we were able to produce this single-crystal aluminum oxide dielectric material,” added Di Zengfeng, a researcher at SIMIT, in a release. “Unlike traditional amorphous dielectric materials, our crystalline sapphire can achieve exceptionally low leakage at just one-nanometer level.”

The researchers hope the improved dielectric properties could lead to more power-efficient devices. [2]

Accelerating computation on sparse data sets

Researchers from Lehigh University and Lawrence Berkeley National Laboratory developed specialized hardware that enables faster computation on data sets that have a high number of zero values, frequent in the fields of bioinformatics and physical sciences. The hardware is portable and can be integrated into general-purpose multi-core computers.

“The accelerating sparse accumulation (ASA) architecture includes a hardware buffer, a hardware cache, and a hardware adder. It takes two sparse matrices, performs a matrix multiplication, and outputs a sparse matrix. The ASA only uses non-zero data when it performs this operation, which makes the architecture more efficient. The hardware buffer and the cache allow the computer processor to easily manage the flow of data; the hardware adder allows the processor to quickly generate values to fill up the empty matrices,” explained Berkely Lab’s Ingrid Ockert in a press release. “Once these values are calculated, the ASA system produces an output. This operation is a building block that the researcher can then use in other functions. For instance, researchers could use these outputs to generate graphs or they could process these outputs through other algorithms such as a Sparse General Matrix-Matrix Multiplication (SpGEMM) algorithm.”

The ASA architecture could accelerate a variety of algorithms. Microbiome research is presented as an example, where it could be used to run metagenomic assembly and similarity clustering algorithms such as Markov Cluster Algorithms that quickly characterize the genetic markers of all of the organisms in a soil sample. [3]

References

[1] I. Giannopoulos, I. Mochi, M. Vockenhuber, Y. Ekinci & D. Kazazis. Extreme ultraviolet lithography reaches 5 nm resolution. Nanoscale, 12.08.2024 https://doi.org/10.1039/D4NR01332H

[2] Zeng, D., Zhang, Z., Xue, Z. et al. Single-crystalline metal-oxide dielectrics for top-gate 2D transistors. Nature (2024). https://doi.org/10.1038/s41586-024-07786-2

[3] Chao Zhang, Maximilian Bremer, Cy Chan, John M Shalf, and Xiaochen Guo. ASA: Accelerating Sparse Accumulation in Column-wise SpGEMM. ACM Transactions on Architecture and Code Optimization (TACO) Volume 19, Issue 4, Article No.: 49, Pages 1-24 https://doi.org/10.1145/3543068

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