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Abstract Defects, such as a black pads and pinholes, are generated on the Ni/Au interface after the electroless nickel immersion gold (ENIG) process. The contamination of plating solutions, including dissolution of the solder resist (SR), side reaction products, and impurities (Cu, Ni, drag-in), can be a cause of the black pad phenomenon. In this study, electroless Ni plating was investigated to determine the correlation between SR dissolution and black pad generation. Three different SR components, monomer, hardener, and photoinitiator were used to examine the effects of the properties of the coating layer. The surface morphology, plating rate, and phosphorus (P) content of the electroless Ni layer with SR additives were analyzed. The black pad mechanism by SR dissolution was examined by electrochemical analysis including the open circuit voltage (OCV) and cyclic voltammetry (CV) in a three-electrode cell. When a few ppm of SR was added, the OCV increased compared to the pure solution. CV revealed a change in hysteresis loop in the oxidation region upon the addition of SR. The contamination in the solution promotes the oxidation reaction rather than the reduction reaction. Therefore, the content of P in the contaminated solution was higher than that of the pure solution, and defects, such as black pad and pinholes, were observed. Graphical abstract Unlabelled Image Highlights • The effects of the SR dissolution on the ENIG process were investigated. • The monomer, hardener and photo initiator were used as SR components. • The correlation between SR dissolution and surface defects was determined. • The increase in the content of P by SR dissolution is considered to increase defects. [ABSTRACT FROM AUTHOR]

There is always a tradeoff between the resolution and the signal-to-noise ratio (SNR) in confocal microscopy. In particular, the pinhole size is very important for maintaining a balance between them. In this paper, we propose a method for improving the lateral resolution and image SNR in confocal microscopy without making any changes to the hardware. By using the fluorescence emission difference (FED) approach, we divide the images acquired by different pinhole sizes into one image acquired by the central pinhole and several images acquired by ring-shaped pinholes. Then, they are added together with the deconvolution method. Simulation and experimental results for fluorescent particles and cells show that our method can achieve a far better resolution than a large pinhole and a higher SNR than a small pinhole. Moreover, our method can improve the performance of classic confocal laser scanning microscopy (CLSM) to a certain extent, especially CLSM with a continuously variable pinhole. [ABSTRACT FROM AUTHOR]

We present an improvement design of a two-dimensional (2D) angular-resolved proton spectrometer for wide-angle measurement of proton beams from high-intensity laser-solid interactions. By using a 2D selective entrance pinhole array with different periods in orthogonal axes, the angular resolution along one dimension is improved by a factor of 6.7. This improvement provides the accessibility to detect the spatial fine structures of the proton energy spectrum. [ABSTRACT FROM AUTHOR]

Computer generated images are most easily generated as pinhole images whereas images obtained with optical lenses exhibit a Depth-of-Field (DOF) effect. This is due to the fact that optical lenses gather light across finite apertures whereas the simulation of a pinhole lens means that the light is gathered through an infinitesimal small aperture, thus producing sharp images at any depth. Simulating the physical process of gathering light across a finite aperture can be done for example with distributed ray tracing, but it is computationally much more expensive than the simulation through an infinitesimal aperture. The usual way of simulating lens effects is therefore to produce a pinhole image and then post processes the image to approximate the DOF. Post processing algorithms are fast but suffer from incorrect visibilities. In this paper, we propose a novel algorithm that tackles the visibility issue with a sparse set of views rendered through the optical center of the lens and several peripheral viewpoints distributed on the lens. All peripheral images are warped towards the central view to create a Layered-Depth-Image (LDI), so that all observed 3D points located on the same central view-ray are stacked on the same pixel of the LDI. Then, each pixel in the LDI is conceptually scattered into a Point-Spread-Function (PSF) and blended in depth order. While the scatter method is very inefficient on a GPU, we propose a selective-gather method for DOF synthesis, which scans the neighborhood of a pixel and blends the colors from the PSFs covering the pixel. Experiments show that the proposed algorithm can synthesize high-quality DOF effects close to the results of distributed ray tracing but at a much higher speed. [ABSTRACT FROM AUTHOR]

We examine quantitatively the instrumental factors that affect the theoretical performance and practical application of conventional pinhole collimation and focusing optics for small-angle neutron scattering (SANS) measurements. We calculate the relative performance of pinhole collimation vis-à-vis focusing by grazing incidence elliptical mirrors and compare the results with a recent ray-tracing simulation to show that the performance gains due to focusing found in the simulation arise largely from assuming a much larger sample size. We also compare measurements of the parasitic scattering from pinhole collimation with that from focusing cylindrical quartz mirrors, and a focusing refractive optic, to stress the importance of signal-to-noise as the true measure of performance for SANS instruments. [ABSTRACT FROM AUTHOR]

Barrier layers were coated by plasma enhanced atomic layer deposition. They had inevitable defects for several reasons and these defects deteriorated the diffusion barrier properties. The size of the pinhole defect decreased with the increase of the layer thickness resulting in enhanced barrier properties, until the thickness reached 20 nm for a single-component aluminum oxide (Al 2 O 3 ) or zirconium oxide (ZrO 2 ) layer. No more enhancement of barrier properties was observed with a further increase of layer thickness, since the defects tended to grow in single-component layers. Alternation of Al 2 O 3 and ZrO 2 layers prevented defect growth by covering the defects with another component, and enhanced the barrier properties when compared with single-component layers. Increase of the number of Al 2 O 3 /ZrO 2 stacks with the same total layer thickness remarkably reduced the water vapor transmission rates value to below 5 × 10 − 5 g/m 2 day at 38 °C and 100% relative humidity. The Al 2 O 3 /ZrO 2 multilayer formed on a polyethylene naphthalate substrate at optimized conditions showed light transmittance greater than 86% at a wavelength of 550 nm, for application as flexible display substrate. [ABSTRACT FROM AUTHOR]

Abstract: A three-dimensional (3D) watermark integral imaging-based watermarking algorithm operating in the cellular automata (CA) domain is presented. Instead of using conventional two-dimensional (2D) watermarking, in this proposed method, an elemental image array (EIA) obtained by recording the rays emanating from a 3D watermark through a pinhole array is used as a watermark to be embedded into the coefficients of CA-transformed pattern. A series of depth-dependent 3D plane images can be reconstructed by the volumetric computational reconstruction (VCR) technique. The embedded 2D EIA is composed of many elemental images possessing their own perspectives of the 3D watermark. The hologram-like 3D properties of the 2D EIA can make a robust reconstruction of the watermark available even though the embedded watermark data may be damaged by image-processing attacks. To embed the watermark imperceptibly, a masking model is introduced to adapt the watermark embedding strength by exploiting the characteristics of the human vision system. In addition, a CA transform with various CA bases and rule numbers can provide many transform planes for watermark embedding. To demonstrate the usefulness of the proposed method, we carry out preliminary experiments and present the experimental results. [Copyright &y& Elsevier]

We perform an optimization of pinhole neutron guide systems under systematically varying conditions. It is investigated how neutron guide systems consisting of a parabolic feeder inside the biological shielding followed by a pinhole and an elliptical guide perform with different pinhole sizes and divergence requirements. We have clarified in which situations such a guide system is a viable choice and when the parabolic feeder is necessary in terms of neutron transport. The advantage of this design is the reduction of background from fast thermal neutrons compared to a system without a pinhole, hence the smallest possible pinhole is of interest. It is found that instruments with divergence requirements of ±1.0° will have excellent neutron transport with a 3×3cm2 pinhole, while lower divergence requirements of ±0.5° can do with a smaller pinhole of 2×2cm2. The feeder effectively reduces the necessary pinhole size, and is especially beneficial for short instruments. In addition to these qualities, a feeder will often smoothen the divergence profile, mostly for longer instruments. [ABSTRACT FROM AUTHOR]

Abstract: This study investigates the effect of print head design on the electrohydrodynamic printed resolution of silk fibroin. Needles with large orifices measuring at 800μm were used to build five different print heads. The print heads were manufactured, tested, and optimized using four different silk fibroin solution concentrations of 10wt.%, 15wt.%, 20wt.%, and 22wt.% at applied voltages that ranged from 10 to 20kV with two different flow rates of 1.5μl/min and 2.0μl/min. Each print head design behaved in a unique manner in terms of printed line characteristics as the flow rate, voltage and concentration were varied. The highest printed resolution of the order of 1μm was achieved using the pinhole reservoir print head. Possible explanations for each of the observed behaviors and design criteria for future print heads are discussed. [Copyright &y& Elsevier]

Abstract: A methodology for measuring the telecentricity of illumination system in lithography tool based on the pinhole imaging is proposed. Illumination light goes through the pinhole located on the reticle plane and forms the pupil-fill image in CCD image sensor. Based on the Fresnel diffraction theory, the image intensity of source in CCD photosurface and the optimization of pinhole size are discussed. By simulating, effects of the stability of telecentricity measuring from non-uniformity of light field and pinhole defocus in different illumination patterns are analyzed respectively. Simulation results prove the effectiveness of this new method. [Copyright &y& Elsevier]

Abstract: The phenomenon of floating gate (FG) crystallization and extrinsic gate oxide breakdown (V bd) are discussed using polysilazane-base inorganic material SOD (Spin-On-Dielectric) as shallow trench isolation (STI) filling for 50nm flash memory fabrication. The pinholes are found along the FG grain boundary in wide active regions because of tensile stress induced by SOD material in STI process, thus gate oxide wears out by following wet cleaning steps. The chemical oxide formation during FG deposition can effectively inhibit gate oxide early breakdown. Moreover, FG sheet resistance (R s) in 550°C/air deposition condition can significantly reduce about 20% in comparison with 520°C/O2 and 400°C/N2 conditions. [Copyright &y& Elsevier]

Abstract: The energy resolved pinhole-imaging method can be applied for surveying the condition of neutron beam extraction systems without the need to remove them. The only condition is the access to a position where direct view of the source is available. Generally this is possible at some stages of the guide system installation or during replacement of first out of pile guide sections. Some facilities have removable sections downstream of the main shutters where the proposed measurement can be performed. The measurement is based on position sensitive neutron detection in time of flight regime. In case of continuous sources, a chopper is required, while in case of pulsed sources the time frame is provided by the source period. The proposed method can be considered an in situ reflectometry experiment. To each pixel of a reflection region corresponds a pixel of the direct view. The ratio of the neutron counts in the image pixel with respect to the corresponding direct pixel gives the reflectivity of the involved mirror plate at the angle which can be determined from the experiment geometry and at the wavelength which results from the flight length and time. The measurement gives an average reflectivity over the mirror surfaces viewed through the given pinhole position and finally the transfer function of the investigated guide sections. The accuracy of the results is affected by the alignment accuracy of the guide sections because the reflection angles are determined with respect to the theoretical positions of the mirror surfaces. As an example, the results obtained at a 100mm high and 25mm wide cold neutron beamline at the Budapest Neutron Centre are presented. [Copyright &y& Elsevier]

Abstract: A theory is developed to describe the pinhole formation and growth in magnetic tunneling junctions (MTJs) using the Kolmogorov–Avrami (KA) model. The theory relates the pinhole dynamics and the gradual degradation of the imperfect barrier layers and then the magnetic junctions under external stress. Form this study, analytical expressions of junction resistance and magnetoresistive (MR) ratio as functions of time are provided to characterize the junction degradation. [Copyright &y& Elsevier]

Abstract: We validated the Monte Carlo package, GATE, for multi-pinhole gamma-ray imaging simulations using calculations and measurements. For these studies requiring large amount of photon histories, the newly designed cluster version of GATE was used. Accordingly that validated simulator allowed us then to evaluate design parameters for 123I-experiments on a prototype multi-pinhole SPECT camera for which analytical calculations were failing due to scatter of high-energy photons. [Copyright &y& Elsevier]

Subtractive imaging in confocal fluorescence light microscopy is based on the subtraction of a suitably weighted widefield image from a confocal image. An approximation to a widefield image can be obtained by detection with an opened confocal pinhole. The subtraction of images enhances the resolution in-plane as well as along the optic axis. Due to the linearity of the approach, the effect of subtractive imaging in Fourier-space corresponds to a reduction of low spatial frequency contributions leading to a relative enhancement of the high frequencies. Along the direction of the optic axis this also results in an improved sectioning. Image processing can achieve a similar effect. However, a 3D volume dataset must be acquired and processed, yielding a result essentially identical to subtractive imaging but superior in signal-to-noise ratio. The latter can be increased further with the technique of weighted averaging in Fourier-space. A comparison of 2D and 3D experimental data analysed with subtractive imaging, the equivalent Fourier-space processing of the confocal data only, and Fourier-space weighted averaging is presented. [Copyright &y& Elsevier]

The performance of a novel and truly compact xenon-filled fast capillary discharge system has been studied by making spectroscopic and pinhole imaging measurements. A few kA current having a fast rise time was applied across the xenon-filled alumina capillary (0.8–1.2 mm diameter and 10–30 mm long) to produce radiation mostly in the EUV region (10–16 nm). The EUV radiation from the capillary was characterized by employing EUV spectrometers and a EUV pinhole camera. Time-integrated, as well as time-resolved, spectra furnished information about the radiation processes from the xenon plasma along with the wall of the capillary. A ‘super’ fast pinching effect is indicated from the pinhole images. The results obtained from the EUV spectroscopic and pinhole measurements are incorporated in this paper. This EUV source may be a strong contender for the basis of next generation lithography assembly. [Copyright &y& Elsevier]