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We demonstrated a coverage-controllable sidewall protective film by controlling the degree of oxidation during plasma-enhanced SiO2 atomic layer deposition (ALD) as a novel technology to suppress bowing in a high-aspect-ratio-contact (HARC) hole etch process. By depositing SiO2 protective film with atomic order on only the top-local region of patterns, to suppress bowing was achieved during HARC etch without the shrinkage of the bottom critical dimension (CD) and etch-stop. In addition, we investigated the parameters that determine the ALD coverage to estimate the coverage profile of sidewall protective film. By analyzing the relationship between activation time and ALD film thickness at each AR, we confirmed that the coverage is determined by the transport of oxygen radical based on the Knudsen transport model. Furthermore, we developed an ALD simulator from the transport model, and successfully estimated the coverage of protective film during etching to improve the verticality of the HARC profile with small bowing-bottom CD bias.

Extreme ultraviolet (EUV) lithography faces major challenges for smaller nodes due to the impact of stochastic and processing failures.1 One of the main challenges for pitch shrink at these nodes is the optimization of the trade-off between break type defects versus bridge type defects as the process window between these defect modes gets smaller.2 In this paper, we examine EUV defect reduction techniques for Chemically Amplified Resist (CAR) and Metal Oxide Resist (MOR) via coater/developer process development combined with optimized etching processes.

We demonstrated a high selective and anisotropic plasma etch of Si3N4 and SiC. The demonstrated process consists of a sequence of ion modification and chemical dry removal steps. The Si3N4 etch with H ion modification showed a high selectivity to SiO2 and SiC films. In addition, we have developed selective etch of SiC with N ion modification. On the other hand, in the patterning etch processes, the fabrication of multi-layer films requires the precision of atomic scale XY CD controllability in complex hole patterns. In order to solve the requirement, we have developed Advanced Quasi- Atomic Layer Etching (ALE) technology which achieved X-Y CD control in oval patterns, along with a wider X-Y CD control margin. Furthermore, in the memory fabrication process, it is required to vertically etch the organic film mask pattern in high aspect ratio (A/R) feature. Therefore, we have developed a new approach that combines atomic layer deposition (ALD) technique and organic film etch process. With this method, we are able to achieve the vertical mask profile. Thus, we will show that these new process technologies have a significant potential to solve critical challenges in the various processes in advanced nodes.

In patterning etch processes, the fabrication of multilayer films requires the precision of atomic scale X-Y CD controllability in complex hole patterns, and reduction of local variability such as Line Edge Roughness (LER), Line Width Roughness (LWR) and Local CDU (LCDU). In order to solve these requirements, we have developed Advanced Quasi-ALE technology which achieved reduction of LCDU, along with a wider X-Y CD control margin. In this paper, we introduce the three benefits of our atomic scale CD and variability control process technology; (1) XY CD control in oval patterns, (2) LCDU reduction and (3) wider etching window using Advanced Quasi-ALE technique. Hence, we will show that it has a significant potential to solve critical challenges in the patterning processes of N5 and beyond.

In recent years, the progression of very large scale integration of semiconductor devices and miniaturization require extension of ultra-high selectivity process and CD control technique exhibiting atomic-layer-level control. We introduce herein a state-of-the-art self-aligned contact (SAC) etching process and multilayer patterning process developed by a new patterning technology using Atomic Layer Etch (ALE) and Atomic Layer Deposition (ALD) towards the 5/7nm generation. SAC etch processes are known to require SiO2 etching capability with ultra-high selectivity to SiN. We developed a modified ALE process [Quasi-ALE] to make it more suitable for SiO2 etch. By adopting this technology to the SAC process, conventional trade-offs between SiO2 etch through capability and SiO2selectivity to SiN in the fine slit pattern is significantly improved. This achievement is enabled by Quasi-ALE’s independent controllability of the radical flux and ion flux, which precisely controls the reaction layer thickness on the surface, allowing etch process at lower ion energy region which is most effective to improve etch selectivity. The advancement of EUV lithography toward manufacturability has accelerated the need for innovation in multilayer lithography stack etches. The patterning of high quality sub lithographic patterns is becoming more challenging, especially in regards to line-roughness (LER/LWR) reduction, and selectivity enhancement of thin EUV-resist. Furthermore, patterning with universal CD shrinkage independent of the pattern types (hole, oval, L/S) is also being required. As a result of various techniques were studied for enhancement of fine pattern formation, “fusion of ALD technology and etching” was confirmed to be very beneficial for its capability of atomic-level formation of surface protection film during the etch process. This technology enabled line-roughness reduction with CD shrink control independent of the pattern-size, since the ALD step is used according to the optimum timing during the etch process, which forms uniform deposition on any type of patterns. As described, precise control of the microfabrication at atomic layer level utilizing Quasi-ALE and ALD technology is becoming mandatory in the generation of 5/7nm.

The reaction of H with solid thin films of C2H4 and C2H6 deposited on the silicon substrate at 13 K was studied using the thermal desorption method and Fourier transform-infrared (FT-IR) spectroscopy. In the reaction of H with C2H4, the formation of C2H6 as a major product and C4H10 as a minor one was observed. The high yield of C2H6 formed from the low-temperature tunneling reaction suggests the occurrence of efficient conversion of C2H4 into C2H6 on the cold dust grains. In the reaction of H with C2H6, no reaction products were detected, suggesting that the recombination reaction H + C2H5 → C2H6 prevails in the solid phase.

In the interstellar clouds, a number of oxygen-containing organic compounds such as alcohols and carbonium compounds have been observed. In order to investigate the role of grain processes for the formation and destruction of these compounds, thin films of acetone and 2-propanol deposited on the copper metal surface at 13 K were reacted with cold gas-phase H atoms (~27 K). The major products from acetone were found to be methane and alcohols (smaller than propanol). 2-propanol was not detected as a reaction product. This indicates that the disproportionation reaction is the major process, but that the recombination one is minor in the reaction of H with the intermediate (CH3)2COH radical. The reaction of H with 2-propanol led to the formation of methane, alcohols, and acetone as major products. The dependences of the film thickness, reaction time, and reaction temperature on the product yields were measured. It is suggested that the diffusion length of the H atoms in the 2-propanol film is longer than that in the acetone film, and consequently greater product yields were obtained for 2-propanol than for acetone with thicker sample films. The temperature-independent product yields in the range of 13-80 K invoke the tunneling processes in the reactions.

The reactions of H atoms with C, O, CO, and CH3CN in solid phase at 12 K were investigated by temperature-programmed mass spectrometry. In the reaction of H atoms with C atoms trapped in the CO matrix, H atoms migrate in the CO matrix and react with trapped C atoms selectively to form CH4. D2O was the major product from the reactions of D atoms with O atoms trapped in a N2O matrix. CH4 was found to be one of the final products from the reactions of H atoms with solid CO. The precursor for the formation of CH4 may be the CH2OH radical. No products were detected from the reaction of H atoms with CH3CN, suggesting that the nitrile group is not amenable to the hydrogenation reactions by H atoms at 12 K. When CH4 molecules are trapped in matrices such as CH3OH and H2O, the desorption of CH4 is greatly suppressed, i.e., from ~50 K for neat CH4 to ~100 K for CH4 in the CH3OH matrix and to ~150 K for CH4 in the H2O matrix.