The problem of semiconductor shortages is well known. It is the anticipated shortage of process gases, which are essential for advanced process control.

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3D NAND memory is finding its way into more and more devices, not only cell phones and personal computers, but also automobiles and data center computers. As demand for memory increases, manufacturers are responding by adding additional layers to their 3D NAND chips.

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Increased memory demand and these additional layers will increase the use of tungsten hexafluoride gas in the chip manufacturing process, which is expected to be in short supply by 2024. Growth in 3D NAND production is also driving demand for nitrogen trifluoride NF3, which likewise is expected to be in short supply within a few years.

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This confirms the helium shortage over the past two years. However, the semiconductor industry consumes only about 5% of global production of helium (most helium is used for medical diagnostic imaging (MRI) applications), and specialty gases such as WF6 are the primary gases used in semiconductor manufacturing.

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Advanced metrology platforms such as ASTON from Atonalp can answer the problem of process gas shortage by enabling in-situ monitoring that can optimize the consumption of WF6 gas.
As the number of layers in memory devices increases, tungsten is used to make word lines; applied as a WF6 gas, its ability to form very good conformal coatings allows it to penetrate the tiniest nooks and crannies of a stack of multilayered 3D NAND memory devices It can also be used as a

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To apply tungsten, the gas used is WF6, which decomposes to leave tungsten metal and generate hydrogen fluoride (HF) gas as a typical byproduct.

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A major challenge is that emission spectroscopy cannot be used for in-situ control of tungsten deposition because ALD processes either do not use plasma or use weak remote hydrogen plasma. Similarly, residual gas analyzers (RGAs) cannot be used for in-situ measurement of mass production because their filament ionization sources are attacked by the corrosive HF gas byproduct.

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These conventional solutions do not provide the in-situ monitoring needed to optimize the use of WF6 in the ALD cycle. The solution to this problem is an advanced metrology platform, such as Atonarp's Aston, which integrates a plasma ionization solution. This is the only system available today that allows in-situ monitoring that can optimize WF6 gas usage.

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While gas shortages are expected for the next several years, Aston's efficiency improvements will reduce dependence on WF6 and other process gases that are expected to be in short supply. Using Aston's in-situ metrology to run the process smarter will minimize the impact of supply shortages and of course reduce overall costs.