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We introduce state-of-the art small-contact etching by a new patterning technique using atomic layer etching (ALE) for sub-5 nm technology generation. In small-contact etching, SiO 2 is etched by using a TiN hard mask with the progress of the miniaturization process. However, when applying the conventional method to small-contact etching with a TiN mask, etch stop is caused by excess deposition on the SiO 2 film. From the results of surface analysis by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy-energy-dispersive X-ray spectroscopy (TEM-EDX), it is considered that the deposition is formed by the reaction of fluorocarbon (FC) plasma and TiN. To solve this problem, we have developed a quasi-ALE technique to improve the ALE process to make it more suitable for SiO 2 etching. By adopting this technique to small-contact etching with a TiN hard mask, etch stop was significantly reduced. Quasi-ALE precisely controls the surface reaction by controlling the radical flux and ion flux independently. Therefore, the reaction of FC plasma and TiN leading to etch stop can be minimized. Quasi-ALE can resolve the etch-stop issue due to the TiN mask used in the conventional method.

We introduce a state-of-the-art self-aligned contact (SAC) process and patterning process developed by new patterning technology using Atomic Layer Etch (ALE) and Atomic Layer Deposition (ALD) towards 5/7nm generation. SAC process is known to require SiO2 etching capability with ultra-high selectivity to SiN. We developed Quasi-ALE technique to improve ALE process to make it more suitable for SiO2 Etch. By adopting this technology to SAC process, the conventional trade-offs between fine process control and SiO2 selectivity to SiN in the fine slit pattern is significantly improved. On the other hand, in the patterning process, CD shrink technique without CD loading is one of the key requirements. By integrating ALD process into the etching flow, we developed a process that can control the CD shrink amount in the atomic layer level without causing CD loading.