Search

The semiconductor industry continues to shrink the device sizes while applying more complex shapes and using diverse materials, which requires parallel improvements in the quality of ultrapure reagents. The need for ultrapure reagents has led to ever-higher demands for the performance of analytical instruments used to detect ultratrace impurities. In this study, nonvolatile impurities in ultrapure reagents were quantified using a scanning mobility particle sizer (SMPS). The performances of three different sample introduction systems, i.e., an electrospray (ES), an aerosol generator with a heating chamber and a Nafion desolvation membrane (NB-II), and a MicroMist nebulizer with a heated cyclonic spray chamber and a three-stage Peltier-cooled desolvation system (MM-APEX), were evaluated for the lower limit of detection of a SMPS. The MM-APEX equipped with the SMPS was able to detect NaCl additives at a concentration of 100 parts per trillion (ppt, ng/L) in ultrapure water, which was approximately 10

HIC1 and RassF1A methylation, which cause loss of gene function, are found in various cancers, including renal cell carcinoma (RCC), and could alter cell stiffness and the content of extracellular vesicles (EVs). These physiological changes may provide a tumoral survival advantage and thus could serve as cellular biomarkers for monitoring cell transformation, although direct associations between these changes and cell transformation remain to be established. As we found HIC1 and RassF1A methylation and expression changes in RCC samples, we examined the effects of gain and loss of HIC1 and RassF1A expression on cell DNA content, cytoskeletal structure, and Piwi-interacting RNA (piRNA) expression in EVs. We found HIC1 and RassF1A hypermethylation and abnormal expression in RCC patient samples was independent of the somatic mutations found in publicly available data. Cell stiffness was reduced in accordance with disrupted cytoskeleton conformation after knockdown of HIC1 or RassF1A. Gain or loss of HIC1 expression induced instability in genomic content, abnormal RassF1A expression disturbed cytoskeletal structure, and the abnormal expression of either gene altered piRNA content in EVs. These results suggest a causal relationship between abnormal tumor suppressor gene expression, cell stiffness, and piRNA expression.

The detection of specific pesticides on food products is essential as these substances pose health risks due to their toxicity. The use of surface-enhanced Raman spectroscopy (SERS) takes advantage of the straightforward technique to obtain fingerprint spectra of target analytes. In this study, SERS-active substrates are made using Au nanoparticles (NPs) coated with a layer of polymer and followed by imprinting with a pesticide&ndash, Cypermethrin, as a molecularly imprinted polymer (MIP). Cypermethrin was eventually removed and formed as template cavities, then denoted as Au NP/MIP, to capture the analogous molecules. The captured molecules situated in-between the areas of high electromagnetic field formed by plasmonic Au NPs result in an effect of SERS. The formation of Au NP/MIP was, respectively, studied through morphological analysis using transmission electron microscopy (TEM) and compositional analysis using X-ray photoelectron spectroscopy (XPS). Two relatively similar pesticides, Cypermethrin and Permethrin, were used as analytes. The results showed that Au NP/MIP was competent to detect both similar molecules despite the imprint being made only by Cypermethrin. Nevertheless, Au NP/MIP has a limited number of imprinted cavities that result in sensing only low concentrations of a pesticide solution. Au NP/MIP is thus a specific design for detecting analogous molecules similar to its template structure.

Surface-enhanced Raman scattering (SERS) technique is competent to trace detection of target species, down to the single molecule level. The detection sensitivity is presumably degraded by the presence of non-specific binding molecules that occupy a SERS-active site (or hot spot) on the substrate surface. In this study, a silver hollow nano-sphere (Ag HNS) with cavity has been particularly designed, followed by depositing dielectric nanoparticles (Di NPs) upon Ag HNS. In the integrated nanostructures, Di NPs/Ag HNS were furthermore confirmed by cutting through the cross sections using the Focused Ion Beam (FIB) technique, which provides the Scanning Electron Microscope (SEM) with Energy-dispersive Spectroscope (EDS) mode for identifying the distribution of Di NPs upon Ag HNS. The results have indicated that Di NPs/Ag HNS exhibits small diameter of cavity, and among Di NPs in this study, Al2O3 with lower dielectric constant provides a much higher SERS enhancement factor (e.g., ~6.2 &times, 107). In this study, to detect trace amounts (e.g., 0.01 ppm) of Ampicillin in water or milk solution, Al2O3 NPs/Ag HNS was found to be more efficient and less influenced by non-specific binding molecules in milk. A substrate with integrated plasmonic and dielectric components was designed to increase the adsorption of target species and to repulse non-specific binding molecules from SERS-active sites.

Health risks posed by the exposure to trace amounts of pesticide residue in agricultural products have gained a lot of concerns, due to their neurotoxic nature. The applications of surface-enhanced Raman Scattering (SERS) as a detection technique have consistently shown its potential as a rapid and sensitive means with minimal sample preparation. In this study, gold nanoparticles (Au NPs) in elliptical shapes were collected into a layer of ordered zirconia concave pores. The porous zirconia layer (pZrO2) was then deposited with Au NPs, denoted as Au NPs (x)/pZrO2, where x indicates the deposition thickness of Au NPs in nm. In the concave structure of pZrO2, Au-ZrO2 and Au-Au interactions provide a synergistic and physical mechanism of SERS, which is anticipated to collect and amplify SERS signals and thereafter improve the enhancement factor (EF) of Au NPs/pZrO2. By taking Rhodamine 6G (R6G) as the test molecule, EF of Au NPs/pZrO2 might reach to 7.0 &times, 107. Au NPs (3.0)/pZrO2 was then optimized and competent to detect pesticides, e.g., phosmet and carbaryl at very low concentrations, corresponding to the maximum residue limits of each, i.e., 0.3 ppm and 0.2 ppm, respectively. Au NPs (3.0)/pZrO2 also showed the effectiveness of distinguishing between phosmet and carbaryl under mixed conditions. Due to the strong affinities of the phosphoric groups and sulfur in phosmet to the Au NPs (3.0)/pZrO2, the substrate exhibited selective detection to this particular pesticide. In this study, Au NPs (3.0)/pZrO2 has thus demonstrated trace detection of residual pesticides, due to the substrate design that intended to provide collective amplification of SERS.

Strontium oxide (SrO) deposited onto a porous titanium (Ti)-based scaffold (P-Ti) is a promising and novel approach for high-throughput transesterification. Notably, a highly porous and calcinated scaffold provides a load-bearable support for a continuous process, while the calcinated SrO catalyst, as it is well distributed inside the porous matrix, can extend its surface contact area with the reactant. In this work, the formation of transesterification reaction with the conversion and production of olive oil to biodiesel inside the porous matrix is particularly examined. The as-designed SrO-coated porous titanium (Ti)-based scaffold with 55% porosity was prepared via a hydrothermal procedure, followed by a dip coating method. Mechanical tests of samples were conducted by a nanoindentator, whereas the physical and chemical structures were identified by IR and Raman Spectroscopies. The results implied that SrO catalysts can be firmly deposited onto a load-bearable, highly porous matrix and play an effective role for the transesterification reaction with the oil mass. It is promising to be employed as a load-bearable support for a continuous transesterification process, such as a process for batch or continuous biodiesel production, under an efficient heating source by a focused microwave system.

Cell stiffness is a potential biomarker for monitoring cellular transformation, metastasis, and drug resistance development. Environmental factors relayed into the cell may result in formation of inheritable markers (e.g., DNA methylation), which provide selectable advantages (e.g., tumor development-favoring changes in cell stiffness). We previously demonstrated that targeted methylation of two tumor suppressor genes, hypermethylated in cancer 1 (HIC1) and Ras-association domain family member 1A (RassF1A), transformed mesenchymal stem cells (MSCs). Here, transformation-associated cytoskeleton and cell stiffness changes were evaluated. Atomic force microscopy (AFM) was used to detect cell stiffness, and immunostaining was used to measure cytoskeleton expression and distribution in cultured cells as well as in vivo. HIC1 and RassF1A methylation (me_HR)-transformed MSCs developed into tumors that clonally expanded in vivo. In me_HR-transformed MSCs, cell stiffness was lost, tubulin expression decreased, and F-actin was disorganized, DNA methylation inhibitor treatment suppressed their tumor progression, but did not fully restore their F-actin organization and stiffness. Thus, me_HR-induced cell transformation was accompanied by the loss of cellular stiffness, suggesting that somatic epigenetic changes provide inheritable selection markers during tumor propagation, but inhibition of oncogenic aberrant DNA methylation cannot restore cellular stiffness fully. Therefore, cell stiffness is a candidate biomarker for cells&rsquo, physiological status.

This study identifies a procedure for the calibration of the Z-magnification of an atomic force microscope below 10 nm by single-atom steps and gives an uncertainty evaluation. A Si(111) surface with periodically arranged single-atom steps was used as a standard reference. The lattice constant of the Si(111) is 0.312 nm, which is traced to SI units through X-ray diffraction. The 33 layers of continuous stacked single-atom steps were scanned and step heights ranging from 0.3 nm to 10 nm were measured and analyzed. The influential factors of calibration for the Z-magnification of an atomic force microscope were identified to estimate the uncertainty according to ISO/IEC Guide 98-3:2008. The relative expanded uncertainties ranged from 4.7% to 5.9%.

This study discusses the strategies on sample preparation to acquire images with sufficient quality for size characterization by scanning electron microscope (SEM) using two commercial ZnO nanoparticles of different surface properties as a demonstration. The central idea is that micrometer sized aggregates of ZnO in powdered forms need to firstly be broken down to nanosized particles through an appropriate process to generate nanoparticle dispersion before being deposited on a flat surface for SEM observation. Analytical tools such as contact angle, dynamic light scattering and zeta potential have been utilized to optimize the procedure for sample preparation and to check the quality of the results. Meanwhile, measurements of zeta potential values on flat surfaces also provide critical information and save lots of time and efforts in selection of suitable substrate for particles of different properties to be attracted and kept on the surface without further aggregation. This simple, low-cost methodology can be generally applied on size characterization of commercial ZnO nanoparticles with limited information from vendors. Keywords: Zinc oxide, Nanoparticles, Methodology

This paper is devoted to investigate an estimation methodology of micro hardness and Young’s modulus of reacted passivation layer of deposited copper thin film in dry and wet environment based a tip-grit atomic force microscope (TGAFM) scratch on copper thin film of silicon wafer. The TGAFM is a modification or attachment of a nanoor micron grit on the tip apex or cantilever beam of a closed-loop control AFM instrument. In this study, a diameter 800 nm SiO2 grit glued on the apex of the tip of AFM is used for experiment. Tip force model has been developed based on Hertzian model and Tresca criterion for stress-strain relationship from the geometries of scratch groove, depth and width to evaluate about microhardness and Young's modulus of copper thin film in regular air and DI-water. Experimental results show that the microhardness (H) is 1.62GPa and the Young's modulus (E) is 160.52GPa of copper thin film in DI-water environment. These mechanical properties of copper thin film is larger than the H= 1.52GPa and E= 126.04GPa for dry environment. Results of this study can be further explored to the grit force reaction on the passivation layer of copper film of chemical mechanical planarization (CMP) process development for semiconductor industry.

Biodegradable elastomers in the form of polyurethane nanoparticles (NPs) were successfully synthesized based on the combinations of two hydrolysis-prone polyester diols by a green water-based process. The anionic nature of the polymers successfully rendered polyurethane NPs (30-50 nm) consisting of approximately 200-300 polymer chains. The mechanical properties and degradation rate could be adjusted by the types and ratios of the component oligodiols in the soft segment. We demonstrated the feasibility using these biodegradable NPs as building blocks to generate self-assembled morphologies in nanometric, micrometric, or bulk scale, bearing excellent elasticity and biocompatibility. The elastic NPs and their various assembled forms represent a series of smart biodegradable elastomers with potential medical applications.

Nanostructures with spikes (NSPs) have been a subject of several surface-enhanced Raman scattering (SERS) applications owing to their significant Raman signal enhancement brought about by the combined effects of interspike coupling and the accumulated induction on the tips of spikes. Thus, NSPs offer great potential as a SERS-active substrate for relevant applications that require a high density of enhanced &ldquo, hot spots&rdquo, In this study, Ag NSPs were synthesized in varying degrees of agglomeration and were thereafter deposited onto a transparent adhesive tape as a flexible substrate for SERS applications, specifically, in the detection of trace amounts of pesticides. These flexible substrates were referred to as Ag NSPs/tape and optimized with an enhancement factor (EF) of ca. 1.7 &times, 107. A strong resulting signal enhancement could be attributed to an optimal degree of agglomeration and, consequently, the distances among/between spikes. Long spikes on the synthesized core of Ag NSPs tend to be loosely spaced, which are suitable in detecting relatively large molecules that could access the spaces among the spikes where &ldquo, are generally formed. Since one side of the transparent tape is adhesive, the paste-and-peel off method was successful in obtaining phosmet and carbaryl residues from apple peels as reflected in the acquired SERS spectra. In situ trace detection of the pesticides at low concentrations down to 10&minus, 7 M could be demonstrated. In situ trace detection of mixed pesticides was possible as the characteristic peaks of both pesticides were observed in equimolar mixtures of the analytes at 10&minus, 2 to 10&minus, 4 M. This study is, thus, premised upon applying for in situ trace detection on e.g., fruit skin.

As the devices scale down, HfO2 is an excellent gate dielectric material and can replace SiO2 in complementary metal-oxide semiconductor technology. However, the mechanical property-based reliability such as wear resistance and deformation mechanism are rarely understood. This paper describes the effect of annealing treatment on 20-nm-thick HfO2 films under varying applied normal forces (31.3–104.2 μN). According to grazing incident X-ray diffraction analysis, the HfO2 thin films changed from amorphous to polycrystalline structure after annealing treatment. The scratch depth relative to initial surface was proportional to normal force. In addition, plowing behavior dominated the deformation mechanism in the form of lumps along the edge of groove by atomic force microscopy images. The annealing-induced crystallization resulted in reduced penetration depth, coefficient of friction, and wear rate at all applied normal forces, indicating that the surface hardness and wear resistance of HfO2 thin films can be enhanced through appropriate annealing treatment. Furthermore, substrate effect caused negative correlation between wear resistance and normal force was not obvious to annealed samples. It could be attributed to the broadening of HfSixOy interfacial layer which enhanced the structure strength.

Accurate determination of Young's modulus and Poisson's ratio is critical when characterizing the mechanical properties of ultra-thin films. In this work, a method to simultaneously measure the Young's modulus and Poisson's ratio of thin films by X-ray techniques combined with a four-point bending fixture is presented. The four-point bending fixture was carried out to purposely induce stresses on the thin film and cause a curvature of the film/wafer system. The induced stresses were measured by the modified conventional X-ray diffraction for film measurements. At the same time, the curvature of the film/wafer system was measured by the X-ray rocking curve. With the film stress derived from the curvature according to the Stoney formula, both the Poisson's ratio and the Young's modulus were evaluated from the plot of lattice d -spacing changes (strain) versus cos 2 α sin 2 ψ . The method was applied to determine thin copper films (~ 180 nm). The estimated Poisson's ratios ranged from 0.18 to 0.24. Compared to the 0.34 for bulk Cu, the deviation between the bulk and the film properties was above ~ 30%. The Young's modulus of the films is 116.7 ± 2.9 GPa, which was comparable to those reported in the literature for ~ 128 GPa.

Nanoscale scratches are applied using an atomic force microscope (AFM) to investigate the mechanical aspect of the material removal process in chemical–mechanical polishing. The scratching experiments are carried out with the AFM, whose probe has an SiO2 particle (radius ~ 400 nm) bonded to it, at low normal forces in deionized (DI) water and a slurry. The experimental results show that the scratch depth increases with increasing normal force. Under a constant force, the scratch depth of the surface in the slurry is significantly larger than that in DI water. This is due to a soft passivation layer generated during chemical interactions on the copper surface. The passivation layer significantly affects the coefficient of friction (COF) and wear rate. At a low scratch depth (below 20 nm), the COF obtained in DI water is ~ 1.74 times larger than that obtained in the slurry. The wear rate obtained in the slurry is larger than that obtained in the DI water.

10-nm-thick atomic layer deposited HfO 2 films were characterized in terms of wear resistance and indentation hardness to investigate the thermal annealing induced impacts on mechanical properties. The wear resistance of ultra-thin films at low loads was characterized using nano-scratch tests with an atomic force microscope. The depth of the nano-scratches decreases with increasing annealing temperature, indicating that the hardness of the annealed films increases with the annealing temperatures. Surface nanoindentation was also performed to confirm the nanoscratch test results. The hardness variation of the annealed films is due to the generation of HfSi x O y induced by the thermal annealing. X-ray photoelectron spectroscopy measurements proved that the hardness of formed HfSi x O y with increasing annealing temperatures. The existence of HfSi x O y broadens the interface, and causes the increase of the interfacial layer thickness. As a result, the surface hardness increases with the increasing HfSi x O y induced by the thermal annealing.

In this study, we proposed an anti-reflection (AR) texture constructed with nano-scale silicon dioxide particle dispersed in Accuglass® T-11 solution to form the structure on the glass by two-steps spin coating technique. We demonstrated the transmittance of the glass with AR texture will be enhanced about 2 % under optimal manufactured conditions. And we have proposed the simulated out-door endurance testing of AR texture which can provide the acceptable transmittance at different relative humidity levels. Based on these findings, we believe that the AR texture with SiO2 nanospheres on the cover glass can be useful in the applications of solar cell, thermal collector, and display device under appropriate environmental conditions.

The mechanical properties of the extracellular matrix play an important role in bio-microenvironment activities. Herein, atomic force microscope (AFM) was used to measure the interaction between Au and Ag nanoparticle (NP) clusters on the surface of human fetal lung cells. Using (3-mercapto-propyl) triethoxysilane (MPTMS), NP clusters were grafted onto the apex of AFM tip, and then, the adhesion force between the tip and the cell was analyzed. The measured adhesion force increased from 92 pN for AFM tip to 332 pN for that modified with MPTMS. The increase is most probably contributed by the nonspecific interactions between the apex of the modified AFM tip and the surface of the cells. The adhesion forces between the surface of NPs clusters grafted AFM tip and that of lung cells were dramatically reduced as NPs clusters were replaced by MPTMS. For the former, as the Au NPs cluster was applied, the adhesion force reached to 122 pN, whereas it significantly augmented with the addition of the cluster's size and dimension on the AFM tip. For the case of Ag cluster grafted on AFM tip, its adhesion force with the surface of the cells significantly lowered and reduced to 56 pN. Presumably, the electrostatic or van der Waals force between the two surfaces results in the variation of measurements. It is also very likely that the cell-surface interactions are probably varied by the nature of the contact surfaces, like the force-distance of attraction. The result is significant for understanding the the nature of the interactions between the surface of NPs and the membrane of lung cells.

The authors critically reviewed published lists of nanoobjects and their physico-chemical properties deemed important for risk assessment and discussed metrological challenges associated with the development of nanoscale reference materials (RMs). Five lists were identified that contained 25 (classes of) nano-objects; only four (gold, silicon dioxide, silver, titanium dioxide) appeared on all lists. Twenty-three properties were identified for characterisation; only (specific) surface area appeared on all lists. The key themes that emerged from this review were: 1) various groups have prioritised nano-objects for development as “candidate RMs” with limited consensus; 2) a lack of harmonised terminology hinders accurate description of many nano-object properties; 3) many properties identified for characterisation are ill-defined or qualitative and hence are not metrologically traceable; 4) standardised protocols are critically needed for characterisation of nano-objects as delivered in relevant media and as administered to toxicological models; 5) the measurement processes being used to characterise a nano-object must be understood because instruments may measure a given sample in a different way; 6) appropriate RMs should be used for both accurate instrument calibration and for more general testing purposes (e.g., protocol validation); 7) there is a need to clarify that where RMs are not available, if “(representative) test materials” that lack reference or certified values may be useful for toxicology testing and 8) there is a need for consensus building within the nanotechnology and environmental, health and safety communities to prioritise RM needs and better define the required properties and (physical or chemical) forms of the candidate materials., JRC.D.2-Standards for Innovation and sustainable Development

Ultra-thin hafnium dioxide (HfO2) is used to replace silicon dioxide to meet the required transistor feature size in advanced semiconductor industry. The process integration compatibility and long-term reliability for the transistors depend on the mechanical performance of ultra-thin HfO2 films. The criteria of reliability including wear resistance, thermal fatigue, and stress-driven failure rely on film adhesion significantly. The adhesion and variations in mechanical properties induced by thermal annealing of the ultra-thin HfO2 films deposited on silicon wafers (HfO2/SiO2/Si) are not fully understood. In this work, the mechanical properties of an atomic layer deposited HfO2 (nominal thickness ≈10 nm) on a silicon wafer were characterized by the diamond-coated tip of an atomic force microscope and compared with those of annealed samples. The results indicate that the annealing process leads to the formation of crystallized HfO2 phases for the atomic layer deposited HfO2. The HfSixOy complex formed at the interface between HfO2 and SiO2/Si, where the thermal diffusion of Hf, Si, and O atoms occurred. The annealing process increases the surface hardness of crystallized HfO2 film and therefore the resistance to nano-scratches. In addition, the annealing process significantly decreases the harmonic contact stiffness (or thereafter eliminate the stress at the interface) and increases the nano-hardness, as measured by vertically sensitive nano-indentation. Quality assessments on as-deposited and annealed HfO2 films can be thereafter used to estimate the mechanical properties and adhesion of ultra-thin HfO2 films on SiO2/Si substrates.

The material removal mechanism of chemical mechanical polishing is simplified as a single nanoparticle scratching the surface of a Cu film based on contact mechanics that relates the size of scratches to the applied force. Scratch experiments were carried out using an atomic force microscope with a SiO2 spherical tip with a radius of 400 nm at low normal forces under three environmental conditions, namely air, deionized (DI) water, and slurry. The experimental results show that for a given force, the scratch depth in a slurry environment is significantly larger than that in a DI water environment, which is due to the slurry chemically interacting with the Cu film surface to generate a soft passivation layer. Consequently, the wear rate in the slurry environment was significantly larger than wear rates in the air environment and in the DI water environment, due to the soft passivation layer generation in the slurry environment. The coefficient of friction (COF) in an air environment is ∼205% and ∼356% larger than those in DI water and slurry environments, respectively, at a given scratch depth. The difference in the COF is due to the effect of buoyancy force in the liquids.

To meet challenges for a smaller transistor feature size, ultra-thin HfO2 high-k dielectric has been used to replace SiO2 for the gate dielectric. In order to accurately analyze the ultra-thin HfO2 films by grazing incidence X-ray reflectivity (GIXRR), an appropriate material model with a proper layer structure is required. However, the accurate model is difficult to obtain, since the interfaces between layers of the ultra-thin HfO2 films are not easily identified, especially when post-deposition annealing process is applied. In this paper, 3.0 nm HfO2 films were prepared by atomic layer deposition on p-type silicon wafer, and annealed in Ar environment with temperatures up to 1000 °C. The layer structures and the role of the interfacial layer of the films in the post-deposition annealing processes were evaluated by X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The experimental results and analysis showed that layer thicknesses, crystal phases and chemical structures of the ultra-thin HfO2 films were significantly dependent on annealing temperatures. The binding energy shifts of Hf 4f, O 1s, and Si 2p elements revealed the formation of Hf silicate (Hf–O–Si bonding) with increasing annealing temperatures. Due to the silicate formation and increasing silicon oxide formation, the interface broadening is highly expected. The structure analysis of the GIXRR spectra using the modified material structure model from the XPS analysis confirmed the interfacial broadening induced by the post-deposition annealing.

To achieve efficient Cu-Chemical–Mechanical Polishing planarization at miniaturized device dimensions, there is a need for a better understanding of the surface integrity induced by the process. Surface quality and stresses are the two selected indices in this article to evaluate the Cu-CMP process induced surface integrity. The thickness of the passivation layer and the penetration depth of abrasives are considered as the main effects for the generations of surface qualities and residual stress. Experimental validation on copper films on silicon wafer was performed by CMP with different pads and slurries to generate varied residual stresses and surface qualities. Depth of scratches and surface roughness were measured by the atomic force microscope. The stress measurements of the thin films were performed by a Grazing Incident X-ray diffraction instrument with its principles based upon modified sin2Ψ method. Accordingly, the surface roughness and stress were related to the thickness of the passivation layer and the CMP process conditions. When the penetration depth is larger than the passivation layer thickness, the roughness values are mainly decided by the selection of pads and the resultant penetration depth. In addition, the residual stress profiles are dependent on the CMP process conditions which include the slurries and pad parameters. The stress profile obtained for the slurry SDK with soft pad Politex composed smallest maximum tensile stress below the surface and a steady transition of stress profile compared to the stress profile obtained at the initial condition. At the condition for the same slurry SDK, but with a hard pad of IC1000, the CMP process induced larger maximum stress and sharper profile transition.

Characterizing surface roughness in nanoscale nondestructively is an urgent need for semiconductor and wafer manufacturing industries. To meet the need, an optical scatter instrument in bidirectional ellipsometry has been developed for characterizing nanoscale surface roughness, in particular, on the wafers after chemical–mechanical polishing. The polarized angular dependence of out-of-plane light-scattering from nanoscale surface roughness is analyzed and characterized. These analysis and characterization results show strong correlations of surface roughness and angular dependence of bidirectional ellipsometric parameters for full field light-scattering. The experimental findings prove good agreement with theoretical predictions for different surface roughnesses. As a result, the nanoscale surface roughness can be accurately measured and characterized by the angular dependence and the polarization of light scattered from surface.

Measurements of the diameter and size distribution of nanoparticles on wafers are critical parameters in the semiconductor industry, essential to control transistor quality and increase production rate. A goniometric optical scatter instrument (GOSI) has been developed that employs polarized light scattering to make measurements of the diameter and size distribution of nanoparticles on bare and thin film coated wafers. This scatter instrument is capable of distinguishing various types of optical scattering characteristics, which correspond to the diameters of the nanoparticles and thin film thickness, on or near the surfaces using the Mueller matrix calculation in Bobbert and Vlieger (1986) [1]. The experimental results of the GOSI system show good agreement with theoretical predictions for nanoparticles of diameter 100, 200, and 300 nm on wafers coated with thin films of 2, 5, and 10 nm thickness. These results demonstrate that the polarization of light scattered by nanoparticles can be used to determine the size of particulate contaminants on bare and thin film coated silicon wafers.

Trace detection of common pesticide residue is necessary to assure safety of fruit and vegetables, given that the potential health risk to consumers is attributed to the contamination of the sources. A simple, rapid and effective means of finding the residue is however required for household purposes. In recent years, the technique in association with surface-enhanced Raman scattering (SERS) has been well developed in particular for trace detection of target molecules. Herein, gold nanoparticles (Au NPs) were integrated with sol-gel spin-coated Zirconia nanofibers (ZrO2 NFs) as a chemically stable substrate and used for SERS application. The morphologies of Au NPs/ZrO2 NFs were adjusted by the precursor concentrations (_X, X = 0.05&ndash, 0.5 M) and the effect of SERS on Au NPs/ZrO2 NFs_X was evaluated by different Raman laser wavelengths using rhodamine 6G as the probe molecule at low concentrations. The target pesticides, phosmet (P1), carbaryl (C1), permethrin (P2) and cypermethrin (C2) were thereafter tested and analyzed. Au NPs/ZrO2 NFs_0.3 exhibited an enhancement factor of 2.1 &times, 107, which could detect P1, C1, P2 and C2 at the concentrations down to 10&minus, 8, 10&minus, 7, 10&minus, 7 and 10&minus, 6 M, respectively. High selectivity to the organophosphates was also found. As the pesticides were dip-coated on an apple and then measured on the diluted juice containing sliced apple peels, the characteristic peaks of each pesticide could be clearly identified. It is thus promising to use NPs/ZrO2 NFs_0.3 as a novel SERS-active substrate for trace detection of pesticide residue upon, for example, fruits or vegetables.

Small angle X-ray scattering (SAXS) was used to characterize the cross section of nanoline gratings fabricated with electron beam lithography (EBL) patterning followed by anisotropic wet etching into a single crystal silicon substrate. SAXS results at normal incidence clearly bear the signature of positional dependent linewidth within the gratings; such non-uniformity is subsequently confirmed with scanning electron microscopy. The proximity effect of EBL is believed to be the cause of the spatial variations of linewidth. To quantitatively fit the SAXS results the linewidth near the periphery of the patterned field needs to be 80% greater than that in the central region, whereas the cross section of nanolines can be modeled as a simple rectangular shape, as expected from the anisotropic wet etching process.

Demands for substrate and film surface planarizations significantly increase as the feature sizes of Integrated Circuit (IC) components continue to shrink. Chemical Mechanical Polishing (CMP), incorporating chemical and mechanical interactions to planarize chemically modified surface layers, has been one of the major manufacturing processes to provide global and local surface planarizations in IC fabrications. Not only is the material removal rate a concern, the qualities of the CMP produced surface are critical as well, such as surface finish, defects and surface stresses. This paper is to examine the CMP produced surface roughness on tungsten or W thin films based on the CMP process conditions. The W thin films with thickness below 1000 nm on silicon wafer were chemical-mechanical polished at different down pressures and platen speeds to produce different surface roughness. The surface roughness measurements were performed by an atomic force microscope (DI D3100). Results show that the quality of surface finish (R a value) is determined by the combined effects of down pressures and platen speeds. An optimal polishing condition is, then, possible for selecting the down pressures and platen speeds.

Residual stress induced by machining is complex and difficult to predict, since it involves mechanical loads, temperature gradients or phase transformation in the generation mechanism. In this work, an experiment with a statistical design for the residual stress tensor was performed to investigate the residual stress profile on a machined surface. In order to understand the generation mechanism of residual stress in machining, three variables and workpiece materials were carefully selected to focus on the mechanical loads and avoid the temperature gradients and phase transformation on the machined surface. The mechanical loads considered here included the chip formation force at the primary shear zone and the plowing force at the tool tip–workpiece contact. Depths of cut and rake angles were selected to alter the chip formation force, and the tool tip radius was designed to emphasize the plowing effect. The workpiece material was aluminum 3003. The experimental results showed that the chip formation force provides basic shapes of the residual stress profile for a machined surface. It decides the depth of the peak residual stress below the surface. However, the plowing force was the dominating effect on the surface residual stress, causing high stresses on the surface. The plowing force can shift the surface stress from tensile to compressive. Additionally, the measured stress tensor proved that in-plane shear stress exists for the machined surface.

Bidirectional ellipsometry has been developed as a technique for distinguishing among various scattering features near surfaces. The polarized angular dependence of out-of-plane light-scattering by the nanoparticles on wafer is calculated and measured according to Rayleigh limit. These calculations and measurements yield angular dependence of bidirectional ellipsometric parameters for out-of-plane scattering. The experimental data show good agreement with theoretical predictions for different diameter of nanoparticles. The results suggest that improvements for accuracy are possible to perform measurements of scattering features from nanoparticles. The angular dependence and the polarization of light scattered by nanoparticles can be used to determine the size of nanoparticulate contaminants on silicon wafers.

Subsurface residual stresses of tungsten films induced by Chemical Mechanical Polishing (CMP) processes were investigated by the Grazing Incident X-Ray Diffraction (GIXRD). Basis of the GIXRD measurement was introduced and the experiments were conducted for residual stress of tungsten film measurements. Experimental procedures of the GIXRD measurements were presented. The obtained residual stresses value of tungsten films from 800 nm to 400 nm varies from 1086.1 ± 105.2 MPa to 1670.6±103.4 MPa prior and after CMP process.

A novel linear piezomotor is developed for machine tool applications. The linear piezomotor consists of three piezoelectric actuators and one monolithic flexure frame which reduces the total number of mechanical elements and interfaces and integrates all the elements. Positioning performance tests are carried out on the linear piezomotor to identify its positioning resolution and accuracy. A laser interferometer is used in the open-loop test to investigate the resolution and positioning behavior, while a linear encoder is used in the closed-loop test to study the positioning accuracy of the linear piezomotor. A discussion is provided on the enhancement of the stiffness and positioning accuracy of the linear piezomotor.

Deformation induced by contact force from the tip is the major measurement uncertainty using atomic force microscope (AFM) for the apex height of nanoparticles. Additionally, the contact force by the AFM tip is difficult and not reliable in traditional tapping and contact modes. In this work, the contact forces applied by the AFM were varied using a peak-force tapping method, which is unique technique to perform force-controlled scanning, to characterize the deformation of nanoparticles. The obtained measurement results were compared with a theoretical model developed for predicting the deformation between PS nanoparticles and tip/substrate. It was found that the deformation occurred at low force as 0.5 nN for polystyrene nanoparticles on mica substrate. The deformation was fully plastic. In addition, the deformation has a linear relationship with contact force, which is consistent with contact mechanics model.

As transistor feature sizes scaling down, the ultra-thin HfO 2 high-k dielectric has been used to replace SiO 2 for the gate dielectric for a better EOT. Grazing Incidence X-ray Reflectivity (GIXRR) is an accurate instrument to analyze the ultra-thin HfO 2 films non-destructively based on an appropriate material model. However, the interfaces between layers of the ultra-thin HfO 2 and other oxide films are not easily identified, especially when post-deposition annealing (PDA) process is applied. In this work, X-ray Photoelectron Spectroscopy (XPS) was used to evaluate the layer structures which were post-annealed up to 1000 °C using furnaces in the Ar ambiances. The experimental results and analysis showed that layer thicknesses, crystal phases and chemical structures of the ultra-thin HfO 2 films were significantly dependent on annealing temperatures. The structure analysis of the GIXRR spectra using the modified material structure model from the XPS analysis confirmed the interfacial broadening induced by the post-deposition annealing.

Bidirectional ellipsometry has been developed as a technique for distinguishing among various scattering features near surfaces. The out-of-plane polarized light-scattering by metallic nanoparticles on wafer is calculated and measured. These calculations and measurements yield angular dependence of bidirectional ellipsometric parameters for out-ofplane scattering. The experimental data show good agreement with theoretical predictions for different diameter of gold spheres. The results suggest that improvements for accuracy are possible to perform measurements of scattering features from metallic nanoparticles. The polarization of light scattered by metallic nanoparticles can be used to determine the size of nano-particulate contaminants on silicon wafers.

High‐k materials, such as HfO2, Al2O3, and many others, have been employed to replace the SiO2 insulator in the gate dielectric device in order to offer significant gate leakage reduction. In this study, the physical properties of hafnium dioxide (HfO2) thin films were analyzed and characterized in the cases of ‘as‐deposited’ and ‘post‐deposition annealing’ (PDA). Ultra‐thin hafnium dioxide films of thickness 2.5, 5 and 10 nm were deposited on Si (100) substrates using atomic layer deposition (ALD) at temperature of 300° C. After deposition, the films were annealed using furnace in Ar ambient for 10 minutes at 450° C, 550° C, 650° C and 750° C. The thickness, density, roughness and the crystalline evolution of the HfO2 films were investigated by Grazing Incidence X‐Ray Reflectometry (GIXRR) and Grazing Incidence X‐Ray Diffraction (GIXRD) for both as‐deposited and post‐annealing conditions. Transmission Electron Microscope (TEM) was used to provide image verification of the two‐layer model applied in XRR f...

Light scattering has shown its powerful diagnostic capability to characterize optical quality surfaces. In this study, the theory of bidirectional reflectance distribution function (BRDF) was used to analyze the metallic nanoparticles’ sizes on wafer surfaces. The BRDF of a surface is defined as the angular distribution of radiance scattered by the surface normalized by the irradiance incident on the surface. A goniometric optical scatter instrument has been developed to perform the BRDF measurements on polarized light scattering on wafer surfaces for the diameter and distribution measurements of metallic nanoparticles. The designed optical scatter instrument is capable of distinguishing various types of optical scattering characteristics, which are corresponding to the diameters of the metallic nanoparticles, near surfaces by using the Mueller matrix calculation. The metallic nanoparticle diameter of measurement is 60 nm on 2 inch thin film wafers. These measurement results demonstrate that the polarization of light scattered by metallic particles can be used to determine the size of metallic nanoparticles on silicon wafers.

The diameter and distribution measurements of nanoparticles on wafers are critical parameters in the semiconductor industry to ensure the quality of the transistors and increase the production rate. A goniometric optical scatter instrument has been developed at CMS / ITRI to readily perform polarized light scattering measurements for the diameter and distribution measurements of nanoparticles on wafers. The designed scatter instrument is capable of distinguishing various types of optical scattering characteristics, which are corresponding to the diameters of the nanoparticles, near surfaces by using the Mueller matrix calculation. The measurement range of nanoparticle diameters is 50 nm to 350 nm on 4 inches to 8 inches thin film wafers. These results demonstrate that the polarization of light scattered by particles can be used to determine the size of particulate contaminants on silicon wafers.

Critical dimension small angle X-ray scattering (CD- SAXS) is a metrology platform that is capable of measuring the average cross section and linewidth roughness (LWR) in test patterns with pitches ranging from 10 to 500 nm with sub-nm precision. These capabilities are obtained by measuring and modeling the scattering intensities of a collimated X-ray beam with sub-nm wavelength from a periodic pattern, such as those found in optical scatterometry targets. In this work, we evaluated the capability of both synchrotron-based and laboratory-scale CD-SAXS for characterizing LWR from measurements of periodic line/space patterns fabricated with extreme ultraviolet (EUV) lithography with sub-50 nm linewidths and designed with programmed roughness amplitude and frequency. For these patterns, CD-SAXS can provide high precision data on cross section dimension, including sidewall angle, line height, linewidth and pitch, as well as the amplitude of LWR. We will also discuss the status of ongoing efforts to compare quantitatively the CD- SAXS data with top-down scanning electron microscopy (CD- SEM) measurements.

Critical dimension small angle X-ray scattering (CD-SAXS) is a metrology platform capable of measuring the average cross section and line width roughness (LWR) with a sub-nm precision in test patterns with line widths ranging from 10 to 500 nm. The X-ray diffraction intensities from a collimated X-ray beam of sub-Angstrom wavelength were collected and analyzed to determine line width, pitch, sidewall angle, LWR, and others structural parameters. The capabilities of lab-scale and synchrotron-based CD-SAXS tools for LWR characterization were tested by measuring a set of identical patterns with designed roughness amplitude and frequency. These test patterns were fabricated using EUV lithography with sub-50 nm linewidths. To compensate for the limited photon flux from the lab-based X-ray source, the incident beam of the lab system was collimated to a less extent than the synchrotron beam-based tool. Consequently, additional desmearing is needed to extract information from data obtained from lab-based equipment. We report the weighted nonlinear least-squares algorithm developed for this purpose, in addiiton to a comparison between the results obtained from our lab system and the synchrotron beam-based tool.

200-nm-thick organosilicate films deposited by mixture of tetraethyl orthosilicate (TEOS) and methyltrimethoxysilane (MTMS) dissolving in different cetrimonium bromide (CTAB)/ethanol ratios were characterized in terms of pore size determination and its distribution. Under the toluene ambient, the pores would adsorb the gas hence elevating the whole film density. The X-ray reflectivity (XRR) equipped with mass flow control was utilized to detect the film density increasing. By fitting with Gaussian function and conversing with Kelvin's equation, the pore size was increased from 6.2 to 10.8 A as the CTAB/ethanol ratio increasing to 0.075. It was attributed to the ethanol and CTAB enhanced the TEOS hollow droplets stability and dissolvability. As the CTAB/ethanol ratio is further increased, the pore size is reversely decreased, owing to the formation of solid microspheres. The non-destructive XRR measurement can evaluate the sub-nano pore sizes and its size distribution, which would fascinate the development and characterization of back-end of line process.

Proceedings of the 14th International Conference, Taipei, Taiwan, 17th–21st June, 2013 Organized by: Center for Measurement Standards/Industrial Technology Research Institute Mechanical and Systems Research Laboratories/Industrial Technology Research Institute National Taiwan University National Cheng Kung University National Taiwan University of Science and Technology National Tsing Hua University Greetings from Chairman of International Programme Committee When Professor Ken Stout and I founded this series of conferences in the United Kingdom more than thirty years ago, we did not anticipate its longevity or its success. Since that first meeting at Leicester, the conference has been often held in England, but also in several other European countries: France, Poland and Sweden, as well as in the United States. Ken, sadly no longer with us, would be proud of what it has achieved and has come to represent. Generations of researchers have presented their new ideas and innovations here which are now embodied in many textbooks and international standards. But this conference in 2013 marks a new departure and perhaps a new future. For the first time it is being held in Asia, reflecting the historic rise of the economies of the Pacific Rim, adding modern technology to their long-existing traditions of ordered insight and precise craftsmanship. Many of you have travelled far to attend this meeting, and we hope you will feel your trouble has been rewarded. We have an excellent selection of papers from all over the world from many of the world's experts, embodying the consolidation of tested ideas as well as the latest advances in the subject. These will be set in context by a glittering array of keynote and invited speakers. On behalf of the International Programme Committee, I am glad to acknowledge the hard work of the members of the Local Organising Committee in putting the programme together and making all the arrangements, and to accept their hospitality. It is my privilege and pleasure to welcome you all to the 14th International Conference on Metrology and Properties of Engineering Surfaces here in Taipei. Tom Thomas Halmstad, 1st June 2013 Greetings from Chairman of Local Organizing Committee It is the great honor of Center for Measurement Standards (CMS), metrology group of Industrial Technology Research Institute (ITRI), to host the 14th International Conference on Metrology and Properties of Engineering Surfaces (Met & Props 2013) from 17–21 June, 2013, in Taipei, Taiwan. In collaboration with four local universities, National Taiwan University (NTU), National Cheng-Kung University (NCKU), National Taiwan University of Science and Technology (NTST) and National Tsing-Hua University (NTHU), we have spent more than one year to prepare this Conference since the approval by the International Programme Committee (IPC). With the guidance from the IPC, we are able to go through the laborious, but important, process of paper selection and review from more than 100 submissions, and also to maintain the tradition in gathering the high quality and state-of-the-art papers. Finally, more than 65 full papers are collected in the programme (oral and poster), and over 120 surface metrologists from 17 countries (or economies) will attend the Conference. As stated in the preface by Professor Thomas, this series of conferences were founded by Tom and late Professor Ken Stout in the United Kingdom more than thirty years ago. I was lucky to join Ken's research group in Birmingham, and to start my journey over surface metrology in 1989, under the financial support from ITRI. With the encouragement from Professor Liam Blunt and endeavors of my colleagues, we are able to hold the Conference first time in emerging Asia, and to ''carry on the heritage and pave the way to the future'' (a Chinese proverb) in surface metrology. Taiwan is also known as Formosa, from Portuguese Ilha Formosa, which means ''Beautiful Island''. Besides the inspiring scientific arrangements, I encourage you to taste Taiwan's wonderful gourmet cuisine, and to explore the beauty of the sweet-potato-shaped island. I wish you a joyful, fruitful and memorable stay. Victor TY Lin, PhD Chairman Local Organizing Committee Met & Props 2013 International Programme Committee Professor Mohamed El Mansori (Arts et Metiers ParisTech, France) Professor H Zahouani (Ecole Centrale de Lyon, France) Professor B-G Rosen (Halmstad University, Sweden) Professor Tom R Thomas (Halmstad University, Sweden) Professor Liam Blunt (University of Huddersfield, UK) Professor Richard Leach (National Physical Laboratory, UK) Professor Chris Brown (Worcester Polytechnic Institute, USA) Dr Jia-Ruey Duann (Center for Measurement Standards, ITRI, Taiwan) International Scientific Committee Professor H Zahouani (Ecole Centrale de Lyon, France) Dr Rolf Kruger-Sehm (Physikalisch-Technische Bundesanstalt, Germany) Professor Pawel Pawlus (Rzeszow University of Technology, Poland) Professor B-G Rosen (Halmstad University, Sweden) Professor Tom R Thomas (Halmstad University, Sweden) Professor Liam Blunt (University of Huddersfield, UK) Professor Derek Chetwynd (University of Warwick, UK) Professor Jane Jiang (University of Huddersfield, UK) Professor Richard Leach (National Physical Laboratory, UK) Professor Paul Scott (University of Huddersfield, UK) Dr Andrew Yacoot (National Physical Laboratory, UK) Professor Chris Brown (Worcester Polytechnic Institute, USA) Dr Chris Evans (University of North Carolina at Charlotte, USA) Professor Jay Raja (University of North Carolina at Charlotte, USA) Dr Ted Vorburger (National Institute of Standards and Technology, USA) Dr Andrew Baker (National Measurement Institute, Australia) Professor David Lee Butler (Nanyang Technological University, Singapore) Dr Benny Cheung (The Hong Kong Polytechnic University, China) Professor Yetai Fei (Hefei University of Technology, China) Dr Kazuya Naoi (National Metrology Institute of Japan, Japan) Dr Heui-Jae Pahk (SNU Precision Co. Ltd., Korea) Professor Jiu-Bin Tan (Harbin Institute of Technology, China) Ms. Siew-Leng Tan (National Metrology Centre (NMC/A*STAR), Singapore) Mr. A. Tonmueanwai (National Institute of Metrology, Thailand (NIMT), Thailand) Professor Kazuhisa Yanagi (Nagaoka University, Japan) Local Organizing Committee Dr Victor Tzeng-Yow Lin (Center for Measurement Standards, ITRI, Taiwan) Professor Kuang-Chao Fan (National Taiwan University, Taiwan) Professor Jen-Fin Lin (ASME Fellow, National Cheng Kung University, Taiwan) Professor Chao-Chang Chen(National Taiwan University of Science and Technology, Taiwan) Professor Shih-Chieh Lin (National Tsing Hua University, Taiwan) Professor Liang-Chia Chen (National Taiwan University, Taiwan) Professor Fang-Jung Shiou (National Taiwan University of Science and Technology, Taiwan) Professor Chun-Hui Chung (National Taiwan University of Science and Technology, Taiwan) Professor Pin-Chuan Chen (National Taiwan University of Science and Technology, Taiwan) Dr Wen-En Fu (Center for Measurement Standards, ITRI, Taiwan)