Robust characteristics of semiconductor-substrate temperature measurement by autocorrelation-type frequency-domain low-coherence interferometry

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For the etching of organic films in H2/N2 plasma, etched profiles are significantly determined by substrate temperature. Here, we control the substrate temperature variation within 3 °C during processing by modulating the plasma-discharge time. The evolution of the cross-sectional profile of line-and-space patterns was observed every 10 s. At 60 and 100 °C, sidewall etching was observed during overetching, but not at 20 °C. During the main etching, the sidewalls were protected by the adsorption of by-products at various temperatures. Moreover, we investigated the temperature dependence of protection layer formation by analyzing the surface components of the organic film. The CN layer formed by N radicals has a protective effect that depends on the components of the CN layer. It was found that the ratio of C–N sp3 to C–N sp2 in the sidewall was highest at 100 °C. By evaluating the radical contribution to CN layer formation, C–N sp3 bonds were observed to be formed by ions and radiation-assisted reaction.

Section: Experimental Methodsmentioning

confidence: 99%

Temperature dependence of protection layer formation on organic trench sidewall in H₂/N₂plasma etching with control of substrate temperature

Fukunaga

Tsutsumi

Takeda

et al. 2017

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“…22) Substrate temperature is monitored by an optical interferometric method. 23) Following the monitor, feedback was applied autonomously in real time to maintain optimal plasma conditions 24) (Fig. 7).…”

Section: Plasma Processing In Semiconductor Manufacturingmentioning

confidence: 99%

Science-based, data-driven developments in plasma processing for material synthesis and device-integration technologies

Kambara

Kawaguchi

Lee

et al. 2022

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Low-temperature plasma processing technologies is essential for material synthesis, device fabrication, and surface treatment. The development of plasma-related products and services requires an understanding of the multiscale complex behaviors of plasma and the hierarchical integration of plasma generation, energy and mass transports through sheath region, surface reactions, and other processes. The importance of science-based and data-driven approaches to controlling systems is argued. The state-of-the-art of deep learning, machine learning, and artificial intelligence in low-temperature plasma science and technology is reviewed. In this review, the requirements and challenges for plasma parameter prediction and processing recipe discovery are asserted by researchers in the fields of material science and plasma processing. It also outlined a science-based, data-driven approach for development of virtual metrology in plasma processes.

“…One control technique is to accurately control the wafer temperature using accurate temperature measurement technology, such as autocorrelation-type frequency domain low coherence interferometry. 33,34) Further investigation is required to achieve highly accurate HAR hole etching.…”

Section: Formation Of Sidewall Striation During High Aspect-ratio Hol...mentioning

confidence: 99%

Formation mechanism of sidewall striation in high-aspect-ratio hole etching

Omura

Hashimoto

Adachi

et al. 2019

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We investigated the formation mechanism of sidewall striations in etched holes with high aspect ratios, with focus on the roles of energetic ions and fluorocarbon radicals. Striations were observed on the sidewalls of holes with high aspect ratios in stacked dielectric films, despite the smooth sidewall of the mask. Argon plasma treatment increased the degree of striation on the carbon mask, while striation was prevented with a cyclic process consisting of a fluorocarbon deposition step and an argon plasma treatment step. The blanket films were irradiated with oblique ion beams in order to simulate the surface reactions on the sidewalls of high aspect ratio holes. Argon ion beams oriented 85° from the surface normal formed severe striations on the blanket fluorocarbon film surface, despite the low roughness of the SiO2 film surface. A thicker fluorocarbon film was observed in regions with striations than deeper regions with smooth sidewalls. The striations formed on the fluorocarbon films at the sidewalls of high aspect ratio holes and transferred to the dielectric films laterally as the hole diameters increased. In addition, as etching proceeded, striations began to form at the deeper regions, depending on the aspect ratios.