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Unbiased roughness measurements: Subtracting out SEM effects, part 2
摘要： The measurement of roughness of small lithographic patterns is biased by noise in the scanning electron microscopes (SEMs) used to make the measurements. Unbiasing the roughness measurement requires the measurement and subtraction of the image noise based on its unique frequency behavior. Improvement to prior white noise removal is achieved by applying a pink noise model. This pink noise removal technique was applied to roughness measurements made with different electron doses (frames of integration), different operating voltages, and different generations of SEM tools. Effective noise removal to create accurate unbiased estimates of the roughness was achieved over a wider range of SEM tool parameter settings than has been previously achieved. As a result, unbiased roughness measurements can now be used to characterize and improve stochastic variability in semiconductor lithography and patterning.
关键词： SEM effects,pink noise model,roughness measurements,electron doses,SEM tools,operating voltages
更新于2025-09-09 09:28:46
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A novel surface roughness measurement method based on the red and green aliasing effect
摘要： A common requirement in many machine learning algorithms is that the training data is sufficient. However, in the visual measurement of surface roughness, this requirement often can't be meet due to the reason that it is time-consuming and expensive to process and label the training samples. To address this issue, this paper proposes a novel method to establish an advanced roughness predictive model with less standard training samples based on inductive transfer learning. The experimental results show that the proposed method has superior measurement performance, and can maintain the average relative error of 12.57% even when the training data is insufficient. This indicates that the proposed method can provide a new strategy for improving the visual roughness measurement performance.
关键词： Roughness measurement,Index design,Inductive transfer learning,Machine vision
更新于2025-09-09 09:28:46
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The Porter-Whitesides Discrepancy: Revisiting Odd-Even Effects in Wetting Properties of n-Alkanethiolate SAMs
摘要： This review discusses the Porter-Whitesides discrepancy in wetting properties of n-alkanethiolate self-assembled monolayers (SAMs). About 25 years ago, Whitesides and coworker failed to observe any odd-even effect in wetting, however, Porter and his coworker did, albeit in select cases. Most previous studies agreed with Whitesides’ results, suggesting the absence of the odd-even effect in hydrophobicity of n-alkanethiolate SAMs. Recent reports have, however, found the odd-even effect in hydrophobicity of n-alkanethiolate SAMs on smooth substrates, indicating that hydrophobicity, and analogous interfacial properties, of n-alkanethiolate SAMs significantly depends on the properties of substrate. Unfortunately, the Whitesides and Porter papers do not report on the quality of the surfaces used. Based on recent work, we inferred that the original discrepancy between Whitesides and Porter can be attributed to the quality of the surface. Odd-even effect of SAMs in charge transport, capacitance, friction, and SAM structure are also discussed in this review to inform the general discussion. The discrepancy between Porter's group and Whitesides’ group could be due to surface roughness, morphology, oxidation, and adventitious contaminants.
关键词： hydrophobicity,roughness,odd-even effect,self-assembled monolayer
更新于2025-09-09 09:28:46
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Thermal Shock Performance of DBA/AMB Substrates Plated by Ni and Ni–P Layers for High-Temperature Applications of Power Device Modules
摘要： The thermal cycling life of direct bonded aluminum (DBA) and active metal brazing (AMB) substrates with two types of plating—Ni electroplating and Ni–P electroless plating—was evaluated by thermal shock tests between ?50 and 250 ?C. AMB substrates with Al2O3 and AlN fractured only after 10 cycles, but with Si3N4 ceramic, they retained good thermal stability even beyond 1000 cycles, regardless of the metallization type. The Ni layer on the surviving AMB substrates with Si3N4 was not damaged, while a crack occurred in the Ni–P layer. For DBA substrates, fracture did not occur up to 1000 cycles for all kind of ceramics. On the other hand, the Ni–P layer was roughened and cracked according to the severe deformation of the aluminum layer, while the Ni layer was not damaged after thermal shock tests. In addition, the deformation mechanism of an Al plate on a ceramic substrate was investigated both by microstructural observation and ?nite element method (FEM) simulation, which con?rmed that grain boundary sliding was a key factor in the severe deformation of the Al layer that resulted in the cracking of the Ni–P layer. The fracture suppression in the Ni layer on DBA/AMB substrates can be attributed to its ductility and higher strength compared with those of Ni–P plating.
关键词： DBA,cracking,Ni–P electroless plating,Ni electroplating,reliability,grain boundary sliding,AMB,thermal shock test,roughness,metallization
更新于2025-09-09 09:28:46
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SiC-TiC nanocomposite for bulk solar absorbers applications: Effect of density and surface roughness on the optical properties
摘要： In this study, the potential of SiC-TiC nano-composites as solar absorbers has been studied. For solar thermal applications, materials with high solar absorptance and low emittance are ideally sought for (spectral selectivity). A semi-molecular sol-gel synthesis route leading to nanometric homogenous composites was described. The resulting SiC-TiC nanocomposite powder was sintered at different temperatures to produce samples with various relative densities (from 57% to 96%). The samples morphology and composition were characterized by several techniques including Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray Spectroscopy (EDX), X-Ray Diffraction (XRD), carbon and oxygen elemental analyses. The link between the surface roughness and the relative density was precised and the effects on the optical properties (0.25–25 μm wavelength range) were studied. Comparisons were made with pure SiC and pure TiC samples with various relative densities. Overall, the sample emittance was found to strongly decrease with the increase in the relative density, leading to a great increase in the spectral selectivity, despite a little decrease in the solar absorptance. The TiC-SiC composite has an intermediate reflectance compared to the pure SiC and the pure TiC samples. With an absorptance of 0.76, an emittance of 0.44 and a selectivity of 1.74, the denser SiC-TiC could be a good candidate for bulk solar applications.
关键词： Concentrated Solar Power,TiC,Selectivity,Density,SiC,Roughness
更新于2025-09-09 09:28:46
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Organic-inorganic composite nanocoatings with superhydrophobicity and thermal stability
摘要： Purpose – This paper aims to investigate the thermal stability and hydrophobicity of difference alkyl chain of silanes with silicon (Si) micro- and nanoparticles. Design/methodology/approach – Sol-gel methods have been used to design superhydrophobic glass substrates through surface modi?cation by using low-surface-energy Isooctyl trimethoxysilane (ITMS) and Ethyl trimethoxysilane (ETMS) solution. Hierarchical double-rough scale solid surface was built by Si micro- and nanoparticles to enhance the surface roughness. The prepared sol was applied onto glass substrate using dip-coating method and was dried at control temperature of 400°C inside the tube furnace. Findings – The glass substrate achieved the water contact angle as high as 154 6 2° and 150.4 6 2° for Si/ITMS and Si/ETMS ?lms, respectively. The Si/ITMS and Si/ETMS also were equipped with low sliding angle as low as 3° and 5°, respectively. The Si micro- and nanoparticles in the coating system have created nanopillars between them, which will suspend the water droplets. Both superhydrophobic coatings have showed good stability against high temperature up to 200°C as there are no changes in WCA shown by both coatings. Si/ITMS ?lm sustains its superhydrophobicity after impacting with further temperature up to 400°C and turns hydrophobic state at 450°C. Research limitations/implications – Findings will be useful to develop superhydrophobic coatings with high thermal stability. Practical implications – Sol method provides a suitable medium for the combination of organic-inorganic network to achieve high hydrophobicity with optimum surface roughness. Originality/value – Application of different alkyl chain groups of silane resin blending with micro- and nanoparticles of Si pigments develops superhydrophobic coatings with high thermal stability.
关键词： Superhydrophobic,Organic coatings,Thermal stability,Coatings,Hierarchical roughness
更新于2025-09-09 09:28:46
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Hyperspectral Terahertz Tomography in Amplitude Contrast
摘要： Hyperspectral Terahertz Tomography in amplitude contrast is presented using a time-domain spectroscopy system in the spectral range 0.3 - 2.5 THz. The Fourier transformed signal data is used to reconstruct test objects’ cross-sections at multiple frequencies using standard filtered backprojection. The full hyperspectral set of images reconstructed at around 300 adjacent spectral points is used to trace the combined contribution of Beer-Lambert volume attenuation, Fresnel reflection losses and Rayleigh roughness scattering losses, which is in good overall agreement with the experimental results. The image quality for Styrofoam (refractive index around 1.02, attenuation coefficient < 1 mm-1) test objects is best in the range 0.8 - 2.0 THz depending on the porosity of the material.
关键词： THz,time-domain spectroscopy,hyperspectral imaging,Rayleigh roughness,hard-field tomography
更新于2025-09-09 09:28:46
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Experimental investigation of white-light interferometry based on sub-dark-field illumination
摘要： In this work, a fast imaging method based on sub-dark -field illumination in white-light interferometry is presented. Applying this method, we successfully resolved the surface profile of test structures even for a smooth surface with a roughness of the order of a few angstroms. The true-colour sequence band is presented, which provides the relationship between the surface colours and the optical path difference. Several characteristics (e.g., basic colour, image contrast, thickness variations, and so on) for the white-light interference images are discussed in detail. Pair images with sub-dark-field illumination in the principal interference fringe were also observed and analysed.
关键词： Interferometry,White light interferometer,Interference microscope,Measurement of roughness
更新于2025-09-09 09:28:46
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Plasma Impact on PI Roughness
摘要： The standard pillar bump structure [1-3] is shown in Figure 2. Polyimide Re-passivation (PI) layer is widely used for pillar bump structure due to the increasingly stringent reliability requirements [4-5]. PI layer serves as stress buffer layer which can enhance the structure reliability performance. And PI will be the direct surface contact material to FCBGA molding compound, so the PI surface roughness is a key factor to the adhesion between PI and molding compound. Lower surface roughness will cause delamination between PI and molding compound while higher surface roughness may cause flip chip process issue like back-grinding tape residue due to higher adhesion between PI and back-grinding tape [6-7]. During the pillar bump process, the PI surface roughness is influenced by many plasma steps like gas and so on. In the present paper, plasma process parameters such as gas, process power and process time are studied in order to get the correlation between these process parameters and PI surface roughness result. This correlation can be used to further study the surface roughness with the assembly site required at the assembly process. As depicted in Figure 3, there are distinctions in the diffraction values of Selected Area Diffraction Pattern (SADP) in different process steps (PI Curing, O2 Descum, RF, Etch, Ar Descum). The influence of different gases plasma on PI surface roughness is quite significant, among which O2 plasma has more significant impact than others, which provides guidance for further research of PI surface roughness in FCBGA
关键词： PI surface roughness,Plasma,PI layer,Adhesion
更新于2025-09-09 09:28:46
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Experimental study on surface generation in optical glass with fluid jet polishing process
摘要： Fluid jet polishing process is an inexpensive technique and capable to produce ultra-smooth surface. In fluid jet polishing process, the surface generation mainly depends upon the size and type of the abrasive particle, the jet pressure, the exposure time, the impact angle, etc. In this work, experimental investigation were carried out to study the influence of different slurry exposure time on surface roughness of optical glass with varying jet pressure, particle diameter and type of particle at 30o impact angle. The surface roughness measurement and surface morphology characterisation were done to understand the surface changes.
关键词： particle size,jet pressure,exposure time,abrasives,surface roughness
更新于2025-09-09 09:28:46