Scatterometry for gate all around (GAA) technology enablement (Conference Presentation)

Charley, Anne-Laure; Mertens, Hans; Horiguchi, N.; Leray, Philippe; Figueiro, Nivea; Sendelbach, Matthew; Koret, Roy; Ger, Avron; Wolfling, Shay

doi:10.1117/12.2300972

Cited by 2 publications

(1 citation statement)

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“…Optical CD (OCD) scatterometry is also emerging as a potential fast metrology technique for cavity depth measurement 5 – 9 However, this technique is model-based and suffers from potential correlations between the numerous geometrical parameters present in a complex 3D GAA device.…”

Section: Introductionmentioning

confidence: 99%

Model-free measurement of lateral recess in gate-all-around transistors with micro hard-X-ray fluorescence

Bogdanowicz

Oniki

Kenis

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

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The processing of gate-all-around (GAA) Si transistors requires several isolated and vertically stacked nanometer-thick Si sheets or wires. For this purpose, the sacrificial SiGe layers of a SiGe/Si superlattice are etched selectively and laterally. Controlling the quantity of etched SiGe material, i.e., the so-called SiGe cavity depth, is critical for optimal device performance. Unfortunately, this critical dimension can only be measured by time-consuming cross-sectional transmission electron microscopy (TEM), which results in limited statistics and hence insufficient control of the cavity depth across wafers and batches. This paper evaluates the capabilities of micro hard x-ray fluorescence (μHXRF) for the determination of cavity depth as a fast and non-destructive alternative to TEM. As we show, μHXRF provides cavity depth values in excellent agreement with TEM. In addition, two critical advantages of the technique demonstrated here are that, thanks to the very high energy of the incoming and emitted X-rays, the SiGe volume is extracted without requiring any complex model and without any correlation to other geometrical parameters of the complex GAA device.

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