Evaluating spin-on carbon materials at low temperatures for high wiggling resistance

Weigand, Michael; Krishnamurthy, Vandana; Wang, Yubao; Qin, Lin; Guerrero, Douglas J.; Simmons, Sean; Carr, Brandy

doi:10.1117/12.2011466

Cited by 6 publications

(3 citation statements)

References 3 publications

(6 reference statements)

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“…However, as photoresist patterns with a high aspect ratio could easily result in a collapse of photoresist patterns, a hard-mask between the photoresist and the substrate film being etched has been introduced for the lithography and etching process, as shown in (i) of Figure 1 a. In general, this lithography and etching process using a hard-mask is followed by (i) hard-mask deposition (or spin-coating) on the substrate being etched, (ii) chemical–mechanical planarization (CMP) and cleaning, (iii) SiON layer chemical-vapor deposition (CVD) and photoresist spin coating, (iv) photoresist exposure and development, (v) SiON layer etching, (vi) hard-mask etching, (vii) photoresist strip, (viii) substrate film etching, and SiON strip [ 10 , 11 ]. Thus, the hard-mask supplies the transfer role of the photoresist patterns via anisotropic dry etchings, requiring high chemical, heat, and etching resistance.…”

Section: Introductionmentioning

confidence: 99%

Surface Transformation of Spin-on-Carbon Film via Forming Carbon Iron Complex for Remarkably Enhanced Polishing Rate

et al. 2022

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To scale down semiconductor devices to a size less than the design rule of 10 nm, lithography using a carbon polymer hard-mask was applied, e.g., spin-on-carbon (SOC) film. Spin coating of the SOC film produces a high surface topography induced by pattern density, requiring chemical–mechanical planarization (CMP) for removing such high surface topography. To achieve a relatively high polishing rate of the SOC film surface, the CMP principally requires a carbon–carbon (C-C) bond breakage on the SOC film surface. A new design of CMP slurry evidently accomplished C-C bond breakage via transformation from a hard surface with strong C-C covalent bonds into a soft surface with a metal carbon complex (i.e., C=Fe=C bonds) during CMP, resulting in a remarkable increase in the rate of the SOC film surface transformation with an increase in ferric catalyst concentration. However, this surface transformation on the SOC film surface resulted in a noticeable increase in the absorption degree (i.e., hydrophilicity) of the SOC film CMP slurry on the polished SOC film surface during CMP. The polishing rate of the SOC film surface decreased notably with increasing ferric catalyst concentration. Therefore, the maximum polishing rate of the SOC film surface (i.e., 272.3 nm/min) could be achieved with a specific ferric catalyst concentration (0.05 wt%), which was around seven times higher than the me-chanical-only CMP.

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Section: Introductionmentioning

confidence: 99%

Surface Transformation of Spin-on-Carbon Film via Forming Carbon Iron Complex for Remarkably Enhanced Polishing Rate

et al. 2022

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“…Recently, spin-on-carbon (SOC) has attracted attention as a hard mask material for pattern transfer into Si for mass production of advanced semiconductor devices [13,14], exhibiting pattern transfer without deformation down to critical dimension (CD) 40 nm with high etch resistance and low defectivity. Previous research has also demonstrated Si fins down to 15 nm with relatively high aspect ratios using SOC for pattern transfer [15].…”

Section: Introductionmentioning

confidence: 99%

High-efficiency diffraction gratings for EUV and soft x-rays using spin-on-carbon underlayers

et al. 2021

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We report on the fabrication and characterization of high-resolution gratings with high efficiency in the extreme ultraviolet (EUV) and soft x-ray ranges using spin-on-carbon (SOC) underlayers. We demonstrate the fabrication of diffraction gratings down to 20 nm half-pitch (HP) on Si3N4 membranes with a bilayer of hydrogen silsesquioxane (HSQ) and spin-on-carbon and show their performance as a grating mask for extreme ultraviolet interference lithography (EUV-IL). High-resolution patterning of HSQ is possible only for thin films due to pattern collapse. The combination of this high-resolution resist with SOC circumvents this problem and enables the fabrication of high aspect ratio nanostructures. Rigorous coupled-wave analysis shows that the bilayer gratings exhibit higher diffraction efficiency than what is feasible with a grating made of HSQ. We also demonstrate a simple and accurate method to experimentally measure the diffraction efficiency of high-resolution gratings by measuring the relative ratio of the dose-to-clear curves of the photoresist. The measured diffraction efficiencies are in good agreement with the theoretically predicted values. Furthermore, we verify our calculations and measurements by printing line/space patterns in chemically amplified resists down to 10 nm HP with both HSQ and bilayer grating masks using EUV-IL. The improved diffraction efficiency of the bilayers is expected to have applications not only in gratings for interference lithography, but also in Fresnel zone plates and gratings for spectroscopy in the EUV and soft x-ray ranges.

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“…CO 2 , COS, O 2 , C 4 F 8 , SF 6 , Ar etc., are usually used during hard mask etching. [8][9][10] Main etching (ME) is the reaction of C 4 F 8 , C 4 F 6 , O 2 , Ar, NF 3 with SiO 2 film. [11][12][13] The fluorine plasmas (F * ) dissociated by fluorocarbons and hydrofluorocarbons can react with ARC to generate gas then volatilize.…”

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confidence: 99%

Optimization of Etch Process for Ultra-Narrow Via in 3D NAND Flash Memory by DOE Method

Ma¹,

Li²,

Zheng³

et al. 2019

ECS J. Solid State Sci. Technol.

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With the increase of storage density in three-dimensional NAND flash memory, technical challenges become more and more severe. Specifically, the etch process of ultra-narrow via is one of the most intricate technical challenges. The critical dimension (CD) of ultra-narrow via is sensitively affected by this process. In this paper, a Design of Experiment (DOE) was presented to develop an optimized etch process. Various statistical correlations between factors and measured results were analyzed by statistical software. Tail phenomenon and cliff effect were explicated by wafer level analysis. A process regression model was employed for process window check and process optimization. Based on data analysis, modeling, and supplementary experiments, the ratio of CxFy to CxHyFz during the etching of anti-reflective coating (ARC) was identified as the most significant factor for the etch process of ultra-narrow via. DOE method is also helpful in developing advanced etch process in state-of-the-art 3D NAND flash memory.

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Evaluating spin-on carbon materials at low temperatures for high wiggling resistance

Cited by 6 publications

References 3 publications

Surface Transformation of Spin-on-Carbon Film via Forming Carbon Iron Complex for Remarkably Enhanced Polishing Rate

Surface Transformation of Spin-on-Carbon Film via Forming Carbon Iron Complex for Remarkably Enhanced Polishing Rate

High-efficiency diffraction gratings for EUV and soft x-rays using spin-on-carbon underlayers

Optimization of Etch Process for Ultra-Narrow Via in 3D NAND Flash Memory by DOE Method

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