According to SK Hynix's recently published 2024 Sustainability Report, the company plans to replace nitrogen trifluoride (NF3) with more environmentally friendly gases that have a lower global warming potential (GWP) in semiconductor cleaning processes. Specifically, Hynix will adopt high-purity fluorine gas mixtures (F2 Mix) as the cleaning gas.

In the etching process of semiconductor production, structures are etched into semiconductor materials, typically carried out in etching machines. The materials generated during the etching process deposit on the walls of the etching tool, necessitating a separate cleaning process. Traditionally, NF3 has been used for cleaning in most cases, but there are also etching machines on the market that utilize high-purity F2/N2 gas mixtures.

These mixtures can effectively remove SiO2 and Si3N4 compounds in an environmentally friendly manner and can serve as a substitute for NF3 as a cleaning gas. In contrast to NF3, which has a GWP value of 17,900, the GWP of the F2/N2 gas mixture is zero. Additionally, the F2/N2 gas mixture can replace other cleaning gases, such as CF4 or C2F6.

SOLVAY has developed and filed patents for various fluorine gas mixtures, including Solvaclean®, which serves as an environmentally friendly gas for CVD cleaning processes. Although its cleaning speed is similar to that of traditional alternatives, it uses less gas per cycle, making it more efficient. It is noteworthy that if F2 is released into the environment, it will immediately decompose into HF, which is absorbed by moisture and ultimately washed away by rain, thus having no impact on the atmosphere. The GWP of the Solvaclean® product is zero.

Currently, Hynix, along with chip manufacturers like Samsung, is actively seeking to expand the application of high-purity fluorine gas mixtures (F2 Mix).

Additionally, the use of hydrogen fluoride (HF) is also on the rise, as HF is widely used in low-temperature etching equipment, with a GWP value of 1 or lower, significantly lower than the fluorocarbon gases (such as CF4 and C4F8, with GWP values of 6,030 and 9,540, respectively) previously used for NAND channel hole etching.

This shift in gas usage is expected to impact the performance of related specialty gas companies.

Article source:

https://mp.weixin.qq.com/s/2SI570OTheo5NjNEk5eZmw