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Fundamental chemistry in heterogeneous catalysis is increasingly explored using operando techniques in order to address the pressure gap between ultrahigh vacuum studies and practical operating pressures. Because most operando experiments focus on the surface and surface-bound species, there is a knowledge gap of the near-surface gas phase and the fundamental information the properties of this region convey about catalytic mechanisms. We demonstrate in situ visualization and measurement of gas-phase species and temperature distributions in operando catalysis experiments using complementary near-surface optical and mass spectrometry techniques. The partial oxidation of methanol over a silver catalyst demonstrates the value of these diagnostic techniques at 600 Torr (800 mbar) pressure and temperatures from 150 to 410 °C. Planar laser-induced fluorescence provides two-dimensional images of the formaldehyde product distribution that show the development of the boundary layer above the catalyst under different flow conditions. Raman scattering imaging provides measurements of a wide range of major species, such as methanol, oxygen, nitrogen, formaldehyde, and water vapor. Near-surface molecular beam mass spectrometry enables simultaneous detection of all species using a gas sampling probe. Detection of gas-phase free radicals, such as CH3 and CH3O, and of minor products, such as acetaldehyde, dimethyl ether, and methyl formate, provides insights into catalytic mechanisms of the partial oxidation of methanol. The combination of these techniques provides a detailed picture of the coupling between the gas phase and surface in heterogeneous catalysis and enables parametric studies under different operating conditions, which will enhance our ability to constrain microkinetic models of heterogeneous catalysis. (Less)

Chalk is a very fine-grained carbonate and can accommodate high porosity which is a key characteristic for high-quality hydrocarbon reservoirs. A standard procedure within Improved Oil Recovery (IOR) is seawater-injection which repressurizes the reservoir pore pressure. Long-term seawater-injection will influence mineralogical processes as dissolution and precipitation of secondary minerals. These secondary minerals (

The rhizosphere is arguably the most complex microbial habitat on Earth, comprising an integrated network of plant roots, soil and a highly diverse microbial community (the rhizosphere microbiome). Understanding, predicting and controlling plant-microbe interactions in the rhizosphere will allow us to harness the plant microbiome as a means to increase or restore plant ecosystem productivity, improve plant responses to a wide range of environmental perturbations, and mitigate the effects of climate change by designing ecosystems for long-term soil carbon storage. To this end, it is imperative to develop new molecular approaches with high spatial resolution to capture interactions at the plant-microbe, microbe-microbe, and plant-plant interfaces. In this work, we designed an imaging sample holder that allows integrated surface imaging tools to map the same locations of a plant root-microbe interface with submicron lateral resolutions, providing novel in vivo analysis of root-microbe interactions. Specifically, confocal fluorescence microscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used for the first time for the correlative imaging of the Brachypodium distachyon root and its interaction with Pseudomonas SW25, a typical plant growth-promoting soil bacterium. Imaging data suggest that the root surface is inhomogeneous and that the interaction between Pseudomonas and Brachypodium roots was confined to only a few spots along the sampled root segments and that the bacterial attachment spots were enriched in Na- and S-related and high-mass organic species. We conclude that the attachment of the Pseudomonas cells to the root surface is outcompeted by strong root-soil mineral interactions but facilitated by the formation of extracellular polymeric substances (EPS).

The purpose of this study is to provide an intravital noninvasive multiphoton microscopic platform for long-term ocular imaging in transgenic fluorescent mice with subcellular resolution. A multiphoton microscopic system with tunable laser output was employed. We designed a mouse holder incorporated with stereotaxic motorized stage for in vivo three-dimensional imaging of ocular surface in 3 transgenic mouse line with fluorescent protein (FP) expression to visualize distinct structures. With our imaging platform and the expression of FPs, we obtained the three-dimensional images across the whole cornea from epithelium to endothelium and in conjunctiva with subcellular resolution in vivo. Specified EGFP expression in corneal epithelium of K5-H2B-EGFP mice helped to identify both corneal and limbal epithelial cells while ubiquitous nuclear FP expression in R26R-GR mice allowed us to visualized nuclei of all cell types. Universal membrane-localized FP in mT/mG mice outlined all cell boundaries, nerve fibers, and capillaries. The simultaneously collected second harmonic generation signals from collagenous stroma provided architectural contrast. Time-lapsed recording enabled monitoring the mitotic activity of corneal epithelial cells and limbal epithelial cells. We developed an intravital multiphoton microscopic stereotaxic imaging platform and showed that, by incorporating FP-expressing transgenic mice, this platform enables in vivo 4-dimensional ophthalmic study at subcellular resolution.

The research herein focused on the first step of the phenomena of surface cleaning by hydrogen peroxide and advanced oxidation treatment, namely chronicling preferential accumulation of nanometer-scale gas bubbles at the solid–residue interface. To demonstrate this phenomenon, the authors coated asphalt onto a glass slide, then immersed the slide in 3% hydrogen peroxide (H2O2) at pH 9, then projected laser light against the opposing side of that glass slide at an angle. As a significant original contribution to science, nanoscale surface imaging quantitatively detected H2O2-induced bubbles that had 70–400 nm dimensions; and it revealed that these bubbles congregated along 50–80% of the asphalt coating's fringe. Tests further showed that when H2O2 and O3 dosing was followed by cavitation and ultrasonics, organic coatings abruptly dislodged from silica grains. With the high resolution of this Surface Imaging Spectroscopy, this laser apparatus could discern between (a) the clear glass slide, (b) reg...

International audience; Alsingle bondSi coated boron steels have been of interest for many years because of their superior mechanical properties and their excellent oxidation resistance. These high strength steels are particularly used in hot stamping processes during which the Alsingle bondSi coating undergoes multiple microstructural transformations. In this study, morphology and structure transformations are investigated using an original approach. Most of the time, the coating evolution is studied in cross section, by ex situ characterization of its different layers after heat treatment. In this work, the evolution of the surface is explored for the first time using in situ high-temperature Environmental Scanning Electron Microscopy (HT-ESEM). The austenitization step reproduced in the ESEM chamber allows a precise description of several surface changes occurring, depending on the temperature range. Among them, the main change in morphology is occurring between 650 and 800 °C and is linked to different reactions between aluminium and bi- and ternary Fe-Al-Si phases. The heating rate is also pointed out as a key parameter that affects the surface morphology. In fact, with low heating rates the surface is mostly composed of hexagonal and rectangular elements coming from τ5 (Fe2Al8Si) structuration, while needle-shaped FeAl3 structures are found for higher heating rates. In addition, it is observed that the heating rate also affects the surface roughness depending on the surface morphology. Finally, the origin of the presence of micrometrics pores appearing between 800 and 900 °C at the coating surface is discussed. Our hypothesis supported by ex situ characterization is that they result from formation of a crystallized oxide layer, probably close to α-Al2O3 structure.

Surface layer matrix-assisted laser desorption ionization mass spectrometry imaging (SL-MALDI-MSI) is a powerful new surface sensitive imaging technique to establish surface component localization of multicomponent polymer materials. This study demonstrates the ability of SL-MALDI-MSI to image defects from foreign materials, material absence, mechanical scribing, and solvent perturbation at the surface of low-molecular-weight poly(methyl methacrylate) and polystyrene thin films. The surface specificity of the SL-MALDI-MSI technique is validated by imaging polystyrene on poly(methyl methacrylate) bilayer films; only polystyrene ions are detected from the surface of the unperturbed polystyrene layer. A key process enabling SL-MALDI-MSI is the solvent-free sublimation of matrix and salt uniformly on the sample’s surface.

Exquisite control of the electrodeposition of metal films and coatings is critical to a number of high technology and manufacturing industries, delivering functionality as\ud diverse as anti-corrosion and anti-wear coatings, electronic device interconnects and energy storage. The frequent involvement of more than one metal motivates the\ud capability to control, maintain and monitor spatial disposition of the component metals, whether as multilayers, alloys or composites. Here we investigate the deposition, evolution and dissolution of single and two-component metal layers involving Ag, Cu, and Sn on Au substrates immersed in the deep eutectic solvent (DES) Ethaline. During galvanostatically controlled stripping of the metals from two-component systems the potential signature in simultaneous thickness electrochemical potential (STEP) measurements provides identification of the dissolving metal; coulometric assay of deposition efficiency is an additional outcome. When combined with quartz crystal microbalance (QCM) frequency responses, the mass change : charge ratio provides oxidation state data; this is significant for Cu in the high chloride environment provided by Ethaline. The spatial distribution (solvent penetration and external roughness) of multiple components in bilayer systems is provided by specular neutron reflectivity (NR). Significantly, the use of the recently established event mode capability shortens the\ud observational timescale of the NR measurements by an order of magnitude, permitting dynamic in situ observations on practically useful timescales. Ag,Cu bilayers of both\ud spatial configurations give identical STEP signatures indicating that, despite theextremely low layer porosity, thermodynamic constraints (rather than spatial accessibility) dictate reactivity; thus, surprisingly, Cu dissolves first in both instances. Sn penetrates the Au electrode on the timescale of deposition; this can be prevented by interposing a layer of either Ag or Cu.

Mass spectrometry imaging is becoming an increasingly common analytical technique due to its ability to provide spatially resolved chemical information. Here, we report a novel imaging approach combining laser ablation with two mass spectrometric techniques, aerosol mass spectrometry and chemical ionization mass spectrometry, separately and in parallel. Both mass spectrometric methods provide the fast response, rapid data acquisition, low detection limits, and high-resolution peak separation desirable for imaging complex samples. Additionally, the two techniques provide complementary information with aerosol mass spectrometry providing near universal detection of all aerosol molecules and chemical ionization mass spectrometry with a heated inlet providing molecular-level detail of both gases and aerosols. The two techniques operate with atmospheric pressure interfaces and require no matrix addition for ionization, allowing for samples to be investigated in their native state under ambient pressure conditions. We demonstrate the ability of laser ablation-aerosol mass spectrometry-chemical ionization mass spectrometry (LA-AMS-CIMS) to create 2D images of both standard compounds and complex mixtures. The results suggest that LA-AMS-CIMS, particularly when combined with advanced data analysis methods, could have broad applications in mass spectrometry imaging applications.

Linear oligomeric [2-(carboxymethylthio)ethylsilsesquioxanes] (LPSQ-COOH) adsorb spontaneously on muscovite mica and form smooth, well-ordered lamellar structures at the liquid-solid interface. Side carboxylic groups, having donor-acceptor character with regard to hydrogen bonds, are engaged both in multipoint molecule-to-substrate interactions and intermolecular cross-linking. The unique arrangement of silsesquioxane macromolecules, with COOH groups situated at the interface with air, produces highly hydrophilic surfaces of good thermal and solvolytic stability. Supramolecular assemblies of LPSQ-COOH were studied using atomic force microscopy (AFM), angle-resolved X-ray photoelectron spectroscopy (ARXPS) and attenuated total reflectance (ATR) FTIR spectroscopy. Comparative height profile analysis combined with ATR-FTIR studies of the spectral regions characteristic of carboxylic groups and C1s core level envelope by XPS confirmed specific interactions between LPSQ-COOH and mica.

Naturally occurring pradimicins (PRMs) show specific recognition of d-mannose (d-Man) in aqueous media, which has never been achieved by artificial small molecules. Although the Ca2+-mediated dimerization of PRMs is essential for their d-Man binding, the dimeric structure has yet to be elucidated, leaving the question open as to how PRMs recognize d-Man. Thus, we herein report the structural elucidation of the dimer by a combination of X-ray crystallography and solid-state NMR spectroscopy. Coupled with our previous knowledge regarding the d-Man binding geometry of PRMs, elucidation of the dimer allowed reliable estimation of the mode of d-Man binding. Based on the binding model, we further developed an azide-functionalized PRM derivative (PRM-Azide) with d-Man binding specificity. Notably, PRM-Azide stained Candida rugosa cells having mannans on their cell surface through conjugation with the tetramethylrhodamine fluorophore. The present study provides the practical demonstration that PRMs can serve as lectin mimics for use in glycobiological studies., ファイル公開：2020-07-18

To investigate whether retinal surface imaging by Cirrus high-definition optical coherence tomography (HD-OCT) clearly depicts the development process of a dissociated optic nerve fiber layer (DONFL) appearance after macular hole (MH) surgery. We reviewed the medical records of the patients who underwent MH surgery with internal limiting membrane peeling. The cases were then selected using three principal criteria: (1) surgeries performed by the same surgeon (S. K.), (2) pre- and postoperative Cirrus HD-OCT imaging, and (3) minimal follow-up of 3 months. All cases received a complete ophthalmologic examination. The presence/absence of a DONFL appearance was determined using a retinal surface image provided by Cirrus HD-OCT. Color fundus photographs were also used for determination if available. Fifteen cases met the criteria. A DONFL appearance was identified in 11 (73%) cases during the postoperative course by retinal surface imaging. A DONFL appearance was not detected in any OCT retinal surface image within the first postoperative month, gradually became distinct between 1 and 3 months after surgery, and remained detectable thereafter in all cases but one whose DONFL appearance became less detectable at 12 months. Indentations of the innermost retinal layer became apparent on cross-sectional OCT images as a DONFL appearance developed on OCT retinal surface images. There were two cases in which the DONFL appearance was not observed on color fundus photographs but detected on OCT retinal surface images. Retinal surface imaging provided by Cirrus HD-OCT appeared to be a promising option in evaluating a DONFL appearance after MH surgery.

Lithium ions in LiMn2O4 crystals have been shown observable by using an aberration corrected electron microscope (R005) which has achieved a sub-50 pm resolution. Based on the annular bright-field image of the observed image, surface imaging of a LiMn2O4 crystal is discussed through simulation. The present simulation showed that ABF images with large convergence angles are sensitive to the top surface profile. A vacancy locating at the top surface of the lithium or manganese atomic columns can be observable with contrast reduced by 10-25% from the columns without vacancy. [DOI: 10.1380/ejssnt.2012.454]

The scanning electron microscope (SEM) is a versatile tool for the characterisation of polymers. The nowadays available broad variety like the conventional SEM (CSEM), the variable pressure SEM (VPSEM) and the environmental SEM (ESEM) enable different investigation techniques for analysis. In this article special modes of performance are discussed. These are the low-voltage mode of the CSEM for the characterisation of surfaces without preparation, the low-vacuum mode of the ESEM utilising an imaging gas for charge compensation at nonconductive samples and the ESEM mode enabling the investigation of wet samples. These modes not only facilitate appropriate characterisations of conventional polymer specimens e.g. for the purpose of fractography, but even open the field for new in situ investigations, where the change of the sample due to e.g. a mechanical influence can be imaged time-resolved.

A fully automated atmospheric pressure ionization platform has been built and coupled with a commercial high-resolution Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS) instrument. The outstanding performance of this instrument allowed screening on the basis of exact masses in imaging mode. The main novel aspect was in the integration of the atmospheric pressure ionization imaging into the current software for matrix-assisted laser desorption ionization (MALDI) imaging, which allows the user of this commercial dual-source mass spectrometer to perform MALDI-MS and different ambient MS imaging from the same user interface and to utilize the same software tools. Desorption electrospray ionization (DESI) and desorption atmospheric pressure photoionization (DAPPI) were chosen to test the ambient surface imaging capabilities of this new ionization platform. Results of DESI imaging experiments performed on brain tissue sections are in agreement with previous MS imaging reports obtained by DESI imaging, but due to the high resolution and mass accuracy of the FTICR instrument it was possible to resolve several ions at the same nominal mass in the DESI-MS spectra of brain tissue. These isobaric interferences at low resolution are due to the overlap of ions from different lipid classes with different biological relevance. It was demonstrated that with the use of high-resolution MS fast imaging screening of lipids can be achieved without any preseparation steps. DAPPI, which is a relatively new and less developed ambient ionization technique compared to DESI, was used in imaging mode for the first time ever. It showed promise in imaging of phytocompounds from plant leaves, and selective ionization of a sterol lipid was achieved by DAPPI from a brain tissue sample.

A novel top-surface imaging process was successfully established using selective chemisorption of amine-functionalized poly(dimethyl siloxane) onto the carboxylic groups formed on the surface of diazoketo-functionalized polymer film by UV light irradiation. The chemisorbed poly(dimethyl siloxane) worked as an efficient etch mask for the subsequent oxygen plasma etching process for pattern generation. High-resolution patterns were resolved with the new imaging process.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a useful tool for the characterization of supported catalyst. Especially, the possibility of surface imaging appears very interesting. The images of not only elements distribution but also molecules or their fragments may be performed. Owing to the fast improvement of time-of-flight secondary ions mass spectrometers, obtaining the surface images with lateral resolution even below 100 nm is possible. The application of TOF-SIMS to the high resolution surface imaging of catalysts surfaces was shown. The influence of the preparation conditions of Co/ZrO2 catalyst on the dispersion and composition of the active phase was investigated. The Co+/Zr+ and CoOH+/Zr+ intensity ratio values were calculated.

Surface metallization by plasma coating enhances desorption/ionization of membrane components such as lipids and sterols in imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS) of tissues and cells. High-resolution images of cholesterol and other membrane components were obtained for neuroblastoma cells and revealed subcellular details (resolving power 1.5 mum). Alternatively, in matrix-enhanced SIMS, 2,5-dihydroxybenzoic acid electrosprayed on neuroblastoma cells allowed intact molecular ion imaging of phosphatidylcholine and sphingomyelin at the cellular level. Gold deposition on top of matrix-coated rat brain tissue sections strongly enhanced image quality and signal intensity in stigmatic matrix-assisted laser desorption/ionization imaging mass spectrometry. High-quality total ion count images were acquired, and the neuropeptide vasopressin was localized in the rat brain tissue section at the hypothalamic area around the third ventricle. Although the mechanism of signal enhancement by gold deposition is under debate, the results we have obtained for cells and tissue sections illustrate the potential of this sample preparation technique for biomolecular surface imaging by mass spectrometry.

The syntheses, spectroscopic characterization, and fluorescence quenching efficiencies of 1,1-silole− and 1,1-silafluorene−phenylenedivinylene polymers are reported. Model dimeric metallole compounds containing a phenylenedivinylene bridge have been synthesized to provide detailed structural and spectroscopic insight into conformational effects and electron delocalization. Poly((tetraphenyl)silole−phenylenedivinylene) and poly(silafluorene−phenylenedivinylene) both maintain a regioregular trans-vinylene Si−C backbone with σ*−π/π* conjugation. Various hydrosilylation catalysts were screened to evaluate their ability to produce high molecular weight polymers and to direct a strictly trans product. Molecular weights (Mw) for these polymers are in the range of 8400−9600. Fluorescence spectroscopy shows a significant bathochromic shift for the silafluorene polymer from solution to the solid state. A surface detection method for the analysis of solid particulates of TNT, DNT, PA, RDX, HMX, Tetryl, TNG, and PETN...

Two- and three-dimensional sub-surface optical beam induced current imaging of a silicon flip-chip is described and is illustrated by results corresponding to 166 nm lateral resolution and an axial performance capable of localising feature depths to around 100 nm accuracy. The experimental results are compared with theoretically modelled performance based on analytic expressions for the system point spread functions valid for high numerical apertures, and are interpreted using numerical geometric ray tracing calculations. Examples of depth-resolved feature profiling are presented and include depth cross-sections through a matrix of tungsten vias and a depth-resolved image of part of a poly-silicon wire.

Cu–Cr alloys, irradiated with a low-energy, high-current electron beam, are analyzed by high-resolution secondary ion mass spectrometry. Mass spectra and images of Cu + and Cr + surface distributions finely reveal the regions enriched in Cu and Cr. For electron beam energies above a threshold value, the formation of a non-equilibrium Cu 1− x Cr x solid solution, extending over sub-micrometer areas is highlighted for the first time. A discussion of the process leading to Cu 1− x Cr x formation is given.

This work presents atomic force microscopy (AFM) results on surface imaging of ultrathin SiO2 oxides with thickness ∼10 nm. The SiO2 was grown by 850 °C dry oxidation of (1 0 0)Si substrates which underwent RCA wet and dry hydrogen plasma procedures prior to oxidation. The pre-oxidation cleans lead to significantly smooth Si surfaces, but on the hydrogenated silicon surfaces formation of hillocks is observed. Oxidation of silicon, although yielding a smooth outer oxide surface, enhances generation of hillocks. The biggest roughness and the most nonuniform distribution of hillocks are obtained on oxides formed on silicon treated in plasma at 300 °C.

We report here a novel technique of surface imaging by X-ray reflection tomography utilizing an ordinary laboratory X-ray source. The technique utilizes the line projection, at different rotation angles, of the reflected beam from a highly reflecting patterned sample at grazing incidence. Filtered back-projection algorithm is applied to the line projection data to reconstruct an image of the pattern on the sample surface. Spatial resolution currently obtained is ~1.6 mm. Nonetheless, we have achieved high correlation between the original image and the reconstructed image. This work is the first step in future efforts of nondestructive X-ray imaging for buried surfaces and interfaces.

Application of atop-surface imaging(TSI) process by silylation to ArF lithography is desirable for ULSI production with minimum feature size for sub-120nm. We evaluated lithographic performances of non-chemically amplified positive TSI photoresist and chemically amplified negative TSI photoresist, both based on phenolic polymer. When off-axis illumination was used, 120nm and 110nm L/S patterns were obtained with non-chemically amplified resist(non-CAR) and chemically amplified resist(CAR) respectively. 100nm L/S patterns of CAR were obtained with strong off-axis illumination using binary intensity mask. CAR was superior to non-CAR in terms of lithographic performances, but inferior to non-CAR in terms of resist pattern collapse. Line edge roughness(LER) of CAR was sufficiently minimized by optimizing silylation bake temperature and it was comparable to that of single layer resist. For the prevention of resist pattern collapse in dry development process, the property of adhesion and resist rigidity is impor ant. This results can help the design of matrix resin of TSI resist for sub-100nm lithography.

The Line-Edge-Roughness (LER) of resist pattern on fine feature has been characterised by means of top/down line width measurements by SEM in Top Surface Imaging (TSI) technology. The resist surface investigation using AFM has provided a correlation between resist Surface Roughness (SR) and the formation mechanism of LER. LER has been improved to 7 nm at 0.18 @mm dense patterns by the optimisation of dry development conditions based on these resist surface investigation.

In this study, red mud (RM), an oxide waste was proposed as reinforcing, synergistic filler for the traditional epoxy intumescent coating (IC). 5.5 wt% of acid-modified and unmodified red mud were introduced into the basic intumescent formulation of ammonium polyphosphate (APP), pentaerythritol (PER) and melamine (MEL). In order to predict effect of modification on its suitability, Field emission electron scanning microscopy and Fourier transform infra red were used to obtain detailed characteristics such as the cell size, pore distribution, homogeneity and chemical composition of the red mud-epoxy carbonaceous char. Both acid-modified and unmodified RM-filled ICs produced chars with smaller and more closely packed cells compared to chars from the unfilled coating. Both coating types had hard carbonaceous metal phosphate coverings that could act as heat barriers. The unmodified red mud was found to be antagonistic to the intumescent action with an expansion of only 2 times the initial thickness. The leached, low iron-red mud produced an expansion of 15 times the initial thickness, but possessed a hollow interior. From these findings, it may be deduced that while acid leaching of red mud may improve intumescent expansion, it would be necessary to optimize the percent filler loading to improve residual mass.

The {0 0 1} surface of natural BaSO 4 was examined in air and aqueous solution using atomic force microscopy (AFM). On the atomic scale, the arrangement of ions on the {0 0 1} cleavage plane is the same (within experimental error) as in the bulk crystal. Fourier transform maps of the atomic scale AFM images yielded surface lattice parameters of a =5.54±0.04 A and b =8.84±0.03 A, indicating that AFM images can be used to obtain crystallographic data of surfaces and to assign surface symmetry as compared with bulk structure. On the micrometre-scale we observed crystallographically orientated monosteps one unit cell (along the c -axis) in height and polysteps as well as etch figures with intrinsic 2 1 screw axis symmetry after dissolution in water on an overall heterogeneous {0 0 1} cleavage plane. In addition to etch pit formation, half-unit-cell-high steps following certain crystal directions ([2 1 0] and [0 1 0]) could be observed, emphasizing the structural control of the dissolution process. Prolonged exposure of a cleaved barite surface to ambient air led to significant surface rearrangement due to the formation and reprecipitation of surface-hydration species within an adsorbed layer of water. Atomistic models of the {0 0 1} cleavage plane, crystallographically oriented step edges along [2 1 0] and [0 1 0] and etch figure boundaries are reported. From these an understanding of the growth and dissolution processes of barite was derived in addition to an explanation of observed step retreat velocities based on surface charging and energetic arguments.

Top surface imaging [TSI] resists have been the subject of sporadic interest over the last decade. Their advantages include improved depth of focus, and the ability to print high aspect ratio features with minimal reflectivity and topographic effects. However, further improvements are needed before this approach satisfies all major IC production requirements. A simple, positive tone TSI process for selective silylation of poly (p-hydroxystyrene), PHS, using 193 nm exposure wavelength has been reported. 1.2 This is a non-chemically amplified approach wherein imagewise exposure causes direct polymer crosslinking, sufficient to allow excellent selectivity during the subsequent silylation step. Poly (p-hydroxystyrene) has demonstrated the best performance for TSI thus far. The resulting images are robust enough to withstand standard IC manufacturing processes. However, photosensitivity for this process is ∼ five-fold slower than desired. This paper describes ongoing work to correct this critical deficiency. We are characterizing substituent effects for various functionality, including poly-hydroxy, nitro, chloro, chloromethyl and methyl moieties on p-hydroxystyrene, in the effort to improve our TSI 193 nm process photospeed. Initial results reported here for poly (2,4-dihydroxystyrene), 2,4-PDHS, indicate that aromatic substitution and molecular weight play significant roles in affecting both crosslinking photosensitivity and silylation rate. In support, we will present E s photospeed, silylation rate and imaging data.

In ambient air, the quality of atomic force microscope (AFM) images can be strongly affected by the capillary effect due to the formation of water meniscus between the AFM Si3N4 tips and the substrates. In view of this, we performed a direct surface modification of the bare tips using a self-assembled monolayer (SAM) of octadecyltrichlorosilane (OTS) to make the tips hydrophobic and eliminate this effect. The images, when collected with the thus obtained modified tips, showed improved performance of tips not only for hard samples but also for fragile systems. This investigation implies a chemical tip modification method to image samples with high resolution in air, by means of making the bare tips hydrophobic.

Scanning probe thermal microscopy has been used to achieve sub-surface imaging of metallic particles embedded in a polymer matrix, using a probe which can act as both ohmic heater and thermometer. A lateral resolution of the order of a micron and a depth detection of a few microns were achieved. Together with the description of the technique and the experimental results obtained, a basic theoretical framework is presented which describes heat flow and temperature distributions within a sample consisting of inclusions buried within a bulk material. Computer models have been developed to give theoretical heat flows and temperature profiles: these are compared here with the experimental data. The theoretical lateral resolution was found to be in good agreement with the experimental observation. We show that theoretical modelling can be used to calibrate the instrument for specific investigations. For example, the technique could be used quantitatively to determine and map thermal conductivity variations across heterogeneous samples, or to determine the depth at which inclusions are located in the case where the thermal conductivities of both the inclusions and the enclosing material are known as well as the geometry of the inclusions.

Near-infrared (NIR) optical imaging is a noninvasive and nonionizing modality that is emerging as a diagnostic tool for breast cancer. The handheld optical devices developed to date using the NIR technology are predominantly developed for spectroscopic applications. A novel handheld probe-based optical imaging device has been recently developed toward area imaging and tomography applications. The three-dimensional (3D) tomographic imaging capabilities of the device have been demonstrated from previous fluorescence studies on tissue phantoms. In the current work, fluorescence imaging studies are performed on tissue phantoms, in vitro, and in vivo tissue models to demonstrate the fast two-dimensional (2D) surface imaging capabilities of this flexible handheld-based optical imaging device, toward clinical breast imaging studies. Preliminary experiments were performed using target(s) of varying volume (0.23 and 0.45 cm(3)) and depth (1-2 cm), using indocyanine green as the fluorescence contrast agent in liquid phantom, in vitro, and in vivo tissue models. The feasibility of fast 2D surface imaging ( approximately 5 seconds) over large surface areas of 36 cm(2) was demonstrated from various tissue models. The surface images could differentiate the target(s) from the background, allowing a rough estimate of the target's location before extensive 3D tomographic analysis (future studies).

The surface imaging processes using germylating agents are investigated. The removability of the resist is expected to be improved by using germylation instead of silylation. The reactivity of several germylating agents with phenolic OH group is evaluated. And germylamine compounds are found to exhibit the highest reactivity among them. Three different types of surface imaging processes are demonstrated and submicron patterns are obtained with each process. Bis(triethylgermyl)amine (BGA) as the germylating agent and PLASMASK 200G-C are used for these processes. The reactivity of BGA is higher than that of HMDS.In the deep UV exposure process, the differences between the germylation and the silylation are investigated on the oxygen dry etching characteristics and the diffusion depth of the reaction. The process using the germylation by BGA is found to have higher oxygen dry etching resistance and lower swelling which corresponds to the diffusion depth in germylated area as compared with the silylation by HMDS. From these results the surface imaging process is expected to have high controllability for linewidth by using the germylation.

Top surface imaging (TSI) techniques using vapor or liquid phase silylation have been investigated extensively as alternatives to conventional resist processing. However, earlier imaging schemes such as diffusion enhanced silylated resist (DESIRE) and digital top surface imaging showed several difficulties limiting the successful application of such TSI approaches. In the case of DESIRE, additional CF4 plasma descum process was required to remove the thin layer of Si incorporated into the cross-linked regions, as some of the Si remained even in the unexposed regions. Also, difference in the cross-linking density and subsequent amount of silicon incorporation across the width of an optically projection printed feature led to non-uniform silylation profiles resulting the difficulty with critical dimension (CD) control of the feature and increased the LER of the overall process. In the case of digital TSI, even though it was developed to overcome these problems with the cross-linking-based silylation process, the concentration of active sites in the exposed polymer varies across the feature width due to the non-uniform energy deposition profile across a feature which results from the non-ideal aerial image produced using optical projection tools. In this study, we have used a diazoketo-functionalized polymer as the platform for the immobilization of amine-functionalized poly(dimethyl siloxane) (amine-PDMS). The diazoketo functional groups undergo Wolff rearrangement to generate carboxylic acid groups upon UV light exposure. This chemistry is exploited to create alternate hydrophilic/hydrophobic patterned regions by selective UV light exposure. The hydrophilic regions that contain carboxylic acid groups predominantly are further used to immobilize amine-PDMS by amide bond formation using carbodiimide coupling chemistry. Due to the high silicon content, the immobilized PDMS acts as the etch barrier for the subsequent oxygen plasma reactive ion etching (O2-RIE) process. Thus, a negative-tone pattern has been successfully generated using O2-RIE process. An amine-PDMS with a molecular weight of 900 was used in this study. Auger electron spectroscopy was employed to characterize the immobilization of amine-PDMS onto UV light exposed regions of diazoketo-functionalized polymer surface. Atomic force microscopy was used to study the surface smoothness after O2-RIE process. Scanning electron microscopy was used to image the pattern profiles formed after O2-RIE process. High resolution pattern profiles are obtained using the TSI process reported in this study.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

High-resolution geophysical methods, such as ground-penetrating radar (GPR) imaging, are increasingly applied to ichnological research. Large vertebrate and invertebrate burrows and tracks can be detected and resolved using center frequencies of > 400 MHz. Geophysical images of bioturbation structures in siliciclastic, carbonate, and evaporite (gypsum) dunes exhibit characteristic electromagnetic signal returns, which are associated with active burrow openings (ground–wave gap), filled burrows (hyperbolic diffraction and “pull up”), and large tracks (concave up patterns). The noninvasive imaging can be used for pseudo-3D visualization (closely spaced survey lines) and monitoring of biogenic activity (repeated surveys). Because biogenic structures induce distinct anomalies in geophysical records collected at frequencies typical of many geological investigations, caution must be taken to avoid misinterpreting them as primary sedimentary structures.

An imaging system for the continuous casting mold copper surface is researched and developed, to replace the on-line manual measuring method, which is used to checking Copper defects such as wearing, scratches and coating loss and other phenomena. Method: The imaging system proposes a special optical loop formed by three Mirrors, selects light source, CCD camera and lens type, designs mechanical transmission system and installation platform. Result: the optical loop and light source can insure imaging large-format object in narrow space. The CCD camera and lens determine the accuracy of horizontal scanning, and the mechanical transmission system ensures accuracy of the vertical scan. The installation platform supplies base and platform for the system. Conclusions: CCD-based copper surface imaging system effectively prevent defects such as missed measuring and low efficiency, etc. It can automatically and accurately shoot copper surface images on-line, and supply basis for image processing, defects identification and copper changing in the late.

The dry development of 0.25 μm diffusion-enhanced silylated resist structures produced in a LAM Research Corporation TCP9400 inductively coupled plasma etcher is studied. The processes consist of a low-selectivity, C 2 F 6 -containing, descum step followed by an oxygen-based main and overetch step. An extensive study, based on statistically designed experiments, shows the effect of different process parameters on anisotropy, selectivity, and the etch rates of silylated and unsilylated resist that occur when using different dry development chemistries. Solutions that independently control and enhance the selectivity and the anisotropy, while maintaining vertical profiles and acceptable etch rates, are demonstrated. Optimal processes for the different chemistries are compared. The effect that the different chemistries exert on the lithographic performance is quantified, and the strong reduction of the proximity effect, both in terms of linewidth and profiles, resulting from SO2 addition is studied. It has been demonstrated that the results also apply to sub-0.25 F m geometries and that none of the tested chemistries interfere with subsequent etching of the polysilicon substrate.

Discotic cholesteric phases with extremely small pitches were obtained with cellobiose derivatives as chiral dopants. These binary mixtures tend to form up to three distinct blue phases. An interesting property of these mixtures is that the blue phases can be supercooled to a glass-like state. Microscopic studies, reflection spectra, and Kossel diagrams all indicate that the three discotic blue phases BPDI, BPDII and BPDIII are analogous to the well-known calamitic modifications. In addition to the optical studies, we investigated the free surfaces of the frozen blue phases using atomic force microscopy.

Most surface imaging resist processes are based on selective incorporation of silicon during silylation, followed by dry development of the resist. The dry development is an important parameter in the resist processing, because it will influence the resist profile and the sensitivity to residues, and, hence, the process latitude. For the DESIRE process, the silicon diffusion profile will be more steep by applying a so called two step dry development, which will result in a steeper resist profile and less residue. For several dry development schemes, the resist profile and the sensitivity to residue are investigated. The etch selectivities corresponding to the various development processes are measured, since they play a major role in the resulting lithographic performance. Further, the useful silylation window with respect to silicon incorporation and DUV induced crosslinking is determined for each type of development. Finally, the resolution and the process latitudes resulting from the different development processes are compared.

Poly(p-vinylbenzoic acid) and its ester are opaque below 300nm and therefore useful in deep UV top surface imaging (TSI), which is a viable technique to overcome the shallow depth of focus and topography effects. In this paper are described two TSI systems utilizing the benzoic acid derivatives in the chemical amplification scheme. The first system is a single-layer negative TSI based on gas-phase silylation of poly(t-butyl p-vinylbenzoate) resist. The second case is the use of poly(p-vinylbenzoic acid) as a strippable bottom layer in conjunction with a thermally-developable, oxygen RIE barrier resist, which comprises an all-dry bilayer, positive TSI system.