Compared with large complex thin - wall castings, civil products have lower requirements on casting quality. However, for the latter, shorten the production cycle, improve the production efficiency of the problem becomes more prominent. The gelation process of common silica sol mainly depends on the dehydration and drying of silica sol, which takes longer time than the gelation of chemical hardening ethyl silicate. Ethyl silicate shell using ammonia dry each layer can be completed in 2h, and the final hardening of silica sol generally takes more than 12h, for some deep holes and other difficult to dry parts of the need for a longer time. At the same time, because the Investment Casting shell needs to be made in layers, each layer needs to be fully dried, to ensure that the lower shell immersion coating will not cause the problem of remelting off, and immersion coating itself, water will be immersed in the dried shell, resulting in a long overall drying cycle. It is a schematic diagram of the production cycle of silica sol shell investment casting under general conditions. As can be seen from the figure, shell making time accounts for more than 50% of the whole casting production cycle. To shorten the delivery time and shell making cycle is the core of the problem. The key factors to shorten the shell-making period can be divided into two aspects: internal cause and external cause. The main internal cause is the characteristics of the binder, and the external cause is the drying condition. Silica Sol Casting industry in China is developing rapidly and its application is also very extensive. Tianhui Machine Co.,Ltd , https://www.thcastings.com
The imaging technology that is the icing on the cake for quantum computing is here!
Recently, a groundbreaking paper published in *Science Advances* introduced a novel non-invasive imaging technology capable of peeking inside the internal structures of silicon crystals. This innovation holds the potential to revolutionize the testing of traditional silicon-based chips and could pave the way for advancements in the field of quantum computing.
An international team comprising researchers from the University of Linz in Austria, University College London, the Swiss Federal Institute of Technology in Zurich, and the Swiss Federal Institute of Technology in Lausanne collaborated to adapt existing microscopy techniques. Specifically, they utilized Scanning Microwave Microscopy (SMM) to examine artificially introduced impurities within silicon chips. A key advantage of this method is that it doesn’t cause any damage to the chip during the imaging process—something that is crucial when dealing with delicate semiconductor materials, which are often doped with impurities to enhance their conductivity and optical properties.
The researchers employed a scanning microwave microscope to analyze samples, focusing on the electrical properties of phosphorus atoms arranged in a precise pattern beneath the silicon crystal's surface. Using this approach, they were able to successfully detect between 1,900 and 4,200 densely packed atoms located 4 to 15 nanometers below the surface. While other methods like Secondary Ion Mass Spectrometry (SIMS) can also detect these impurities, SMM stands out due to its non-destructive nature.
In an email exchange with *IEEE Spectrum*, Georg Gramse, head of the laboratory at the University of Linz, Austria, emphasized the broader implications of this technology:
“From the perspective of scanning silicon chips, this new development holds immense promise for the global semiconductor industry. As chip integration continues to shrink, the measurement process becomes increasingly challenging and time-consuming, often risking damage to the chip itself.â€
Further evidence of the technique’s efficacy can be seen in the comparison between SMM and Vector Network Analyzer (VNA) measurements for materials, which show remarkable consistency. These new imaging capabilities are particularly significant for advancing phosphorus-silicon quantum computers, as they enable seamless integration with existing detection tools. This breakthrough could dramatically accelerate the creation of three-dimensional structures by applying the technique iteratively during lithography processes.
Looking ahead, Gramse noted, “Currently, our focus is on understanding the physical properties of the phosphorus atomic layer, which represents a critical next step toward the realization of phosphorus-silicon quantum computers.â€
This innovative technology not only addresses current limitations in chip testing but also opens new frontiers in quantum computing research, marking a pivotal moment in the evolution of semiconductor science.