scholarly journals ESTIMATION OF TOPOGRAPHIC DEFECTS DIMENSIONS OF SEMICONDUCTOR SILICON STRUCTURES

2018 ◽  
Vol 9 (1) ◽  
pp. 74-84
Author(s):  
S. F. Sianko ◽  
V. A. Zelenin
Keyword(s):  
Calculation Method ◽  
Target Surface ◽  
Curvature Radius ◽  
Surface Geometry ◽  
Semiconductor Wafer ◽  
Semiconductor Silicon ◽  
Quantitative Characteristics ◽  
Silicon Structures ◽  
Analytical Expressions ◽  
Acceptability Criteria

The effect of non-flatness of semiconductor wafers on characteristics of manufactured devices is shown through defocusing of an image of a topological layout of a structure being formed and through reduction of resolution at photolithographic processing. For quality control of non-flatness the Makyoh method is widely used. However, it does not allow obtaining quantitative characteristics of observed defects, which essentially restricts its application. The objective of this work has been developing of a calculation method for dimensions of topographic defects of wafers having semiconductor structures formed on them, which has allowed determining acceptability criteria for wafers, depending on defects dimensions and conducting their timely penalization.A calculation method under development is based on deduction of relationships linking distortion of image elements to curvature of local sections of a semiconductor wafer that has formed structures. These structures have been considered to be image finite elements and within this range the curvature radius has been assumed to be constant. Sequential calculation of deviation of element ends from ideal plane based on determining their curvature radius has allowed obtaining geometry of a target surface in a set range of elements. Conditions of image formation and requirements to structures have been determined.Analytical expressions relating a deviation value of elements of a light-to-dark image with surface geometry have been obtained. This allows conducting effective quantitative control of observed topographic defects both under production and research conditions. Examples of calculation of topographic defects of semiconductor silicon wafers have been provided. Comparison of the obtained results with the data obtained by conventional methods has shown their complete conformity.

Mechanical behavior of butt curved adhesive joints subjected to bending

2021 ◽  
Vol 63 (7) ◽  
pp. 639-644
Author(s):  
Yaşar Ayaz ◽  
Çitil Şerif
Keyword(s):  
Mechanical Behavior ◽  
Applied Load ◽  
Adhesive Bonding ◽  
Great Influence ◽  
Lap Joints ◽  
Three Dimensions ◽  
Cohesive Zone Modeling ◽  
Radius Of Curvature ◽  
Curvature Radius ◽  
Surface Geometry

Abstract Factors such as the surface geometry of a joint, the direction of the applied load, and the type of adhesive used have a great influence on the strength of a joint in adhesive bonding. In adhesively bonded joints (ABJ), it is possible to improve surface geometry by forming various geometric surfaces. ABJs are not very resistant to peeling stress, thus requiring that a bonding model be analyzed according to the direction of the applied load to prevent peeling stress. In this study, a butt curved joint was prepared from aluminum plates (A2024-T3) to improve the surface geometry of the joint. The mechanical behavior of the joints in three-dimensions and subjected to bending were investigated depending on an increase in the curvature radius. The adhesive DP810 was used for bonding. The finite element analysis was performed in ANSYS and cohesive zone modeling was used for a simulation of the damage growth in the adhesive layer. The results of bilinear and exponential models were found to be more appropriate to the experimental results. When the radius of curvature increases, the damage load carried decreases in the butt curved lap joints. It was seen that decreases in the curvature radius significantly decrease normal stress.

Influence of distribution parameters of rough surface asperities on the contact fatigue life of gears

2019 ◽  
Vol 234 (6) ◽  
pp. 821-832
Author(s):  
Wen Yuqin ◽  
Tang Jinyuan ◽  
Zhou Wei
Keyword(s):  
Fatigue Life ◽  
Calculation Method ◽  
Contact Fatigue ◽  
Radius Of Curvature ◽  
Curvature Radius ◽  
Quantitative Calculation ◽  
Distribution Parameters ◽  
Contact Fatigue Life ◽  
The Mean ◽  
Meshing Process

The influence of the distribution parameters of asperities, i.e. mean radius of curvature of asperities β, density of asperities η, and standard deviation of asperity heights σ, on the contact fatigue life of gears is first studied in this paper. Based on the elastic–plastic contact model of asperities, the surface contact pressure and subsurface stress field during the gear meshing process are calculated by the iterative calculation method. According to the multi-axis fatigue life model, the calculation method of fatigue life under different distribution parameters of asperities in the gear meshing process is obtained. The quantitative calculation results of fatigue life and measured distribution parameters of asperities are analyzed. The relationship between the fatigue life and the distribution parameters of asperities on the measured gear surface is calculated and analyzed quantitatively. The following conclusions are drawn: (1) when the roughness value Ra is less than 0.3 µm, the contact fatigue life of gears with rough surfaces is close to that of smooth surfaces; (2) when the roughness value Ra ranges from 0.5 µm to 0.9 µm, the contact fatigue failure occurs near the surface (micro-pitting); (3) under the same roughness value Ra, the contact fatigue life of the gear decreases with the decrease of the density of the asperity and the mean curvature radius of the asperity. The mean radius of curvature of the asperity has a greater influence on the contact fatigue life than the density of the asperity.

scholarly journals Segmentation of Change in Surface Geometry Analysis for Cultural Heritage Applications

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4899
Author(s):  
Sunita Saha ◽  
Jacek Martusewicz ◽  
Noëlle L. W. Streeton ◽  
Robert Sitnik
Keyword(s):  
Cultural Heritage ◽  
Target Surface ◽  
Segmentation Method ◽  
Surface Geometry ◽  
Time Intervals ◽  
Measurement Results ◽  
Local Distance ◽  
Geometrical Data ◽  
Point To Point ◽  
Geometry Analysis

This work proposes a change-based segmentation method for applications to cultural heritage (CH) imaging to perform monitoring and assess changes at each surface point. It can be used as a support or component of the 3D sensors to analyze surface geometry changes. In this research, we proposed a new method to identify surface changes employing segmentation based on 3D geometrical data acquired at different time intervals. The geometrical comparison was performed by calculating point-to-point Euclidean distances for each pair of surface points between the target and source geometry models. Four other methods for local distance measurement were proposed and tested. In the segmentation method, we analyze the local histograms of the distances between the measuring points of the source and target models. Then the parameters of these histograms are determined, and predefined classes are assigned to target surface points. The proposed methodology was evaluated by considering two different case studies of restoration issues on CH surfaces and monitoring them over time. The results were presented with a colormap visualization for each category of the detected change in the analysis. The proposed segmentation method will help in the field of conservation and restoration for the documentation and quantification of geometrical surface change information. This analysis can help in decision-making for the assessment of damage and potential prevention of further damage, and the interpretation of measurement results.

scholarly journals Estimating of Bending Force and Curvature of the Bending Plate in a Three-Roller Bending System Using Finite Element Simulation and Analytical Modeling

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1204
Author(s):  
Ionel Gavrilescu ◽  
Doina Boazu ◽  
Felicia Stan
Keyword(s):  
Finite Element ◽  
Plastic Hinge ◽  
Plate Thickness ◽  
Practical Importance ◽  
Vertical Displacement ◽  
Curvature Radius ◽  
Bending Force ◽  
Wide Range ◽  
Bending Process ◽  
Analytical Expressions

Many industries such as shipbuilding require steel bending plates in a wide range of radii, thus bending machines are often designed and produced on a custom basis in shipyards. From a design perspective, however, the bending force and the radius of the bending plate as a function of vertical displacement of the upper roller must be known. In this paper, a hybrid numerical–analytical approach is proposed to investigate the three-roller bending process for two plates of steel used in the naval industry. Firstly, the bending process is modeled using the finite element (FE) method and regression models for the bending force as a function of plate thickness and vertical displacement of the upper roller were constructed. Then, based on the findings from FE analysis, using the bent bar theory, two analytical expressions for the bending force were derived. Using geometric and deformation compatibilities, analytical expressions for the vertical displacement of the upper roller as a function of the curvature of the bending plate were also developed. The FE results suggest that the cross section of the plate is practically a plastic hinge in the tangent area of the upper roller and that the deformation compatibilities must be considered in order to estimate the curvature radius of the bending plate using analytical formulations. These results are of practical importance in designing rolling machines to estimate the setting parameters.

scholarly journals Projection of Flat-Plane Fluxmap Images Onto Non-Flat Receiver Surfaces

2011 ◽  
Author(s):  
Julius Yellowhair ◽  
Charles E. Andraka
Keyword(s):  
Flat Plate ◽  
Target Surface ◽  
Software Tool ◽  
Product Evaluation ◽  
Surface Geometry ◽  
Beam Characterization ◽  
Flux Profile ◽  
Analytical Tools ◽  
Engine Systems ◽  
Absorber Surface

When designing or evaluating a dish concentrator system, it is desirable to determine the incident flux profile on the receiver surface, regardless of the absorber surface geometry. During the design process, analytical tools are used to predict flux profiles. During product evaluation, a flux-mapper (beam characterization system) can be used to measure the flux profile on a flat target surface. Radiosity concerns typically limit flux mapping measurements of dish-engine systems to a flat plate target. We propose and demonstrate an analytical method to project such a measured flat-target flux profile onto a non-flat receiver surface. We analytically estimate the angular content of the flux profile, and use this estimate combined with the measured flat-plate flux profile to project an estimate of the flux pattern onto another receiver surface. In this paper, we analytically demonstrate the technique. We first model a dish concentrator using CIRCE2. We then develop an analytic flux-map, in CIRCE2, on a flat target, simulating a flux-mapper output. Next, we use our new software tool and the CIRCE2 angular flux binning to project this flux pattern onto a non-flat receiver surface. Finally, we run a CIRCE2 model of the same dish with the non-flat target geometry, and compare this CIRCE2 output to the projected data. We also demonstrate the technique using a measured flux-map from a dish system in the field.

Optimization Design of Cylinder Grating Used for Non-Contact Speed Measurement

2013 ◽  
Vol 312 ◽  
pp. 95-100
Author(s):  
Guo Sheng Zhang ◽  
Yan Xu
Keyword(s):  
Light Intensity ◽  
Optimization Design ◽  
Optical Path Length ◽  
Grating Period ◽  
Curvature Radius ◽  
Length Variation ◽  
Speed Measurement ◽  
Total Light ◽  
Analytical Expressions ◽  
Fraunhofer Approximation

In order to realize the detection of diffractive light after the image segmentation using cylinder grating, the parameters of a cylinder grating was optimized using the wave optics theory. By analyzing the relation of optical path length variation with the diffraction angle of single cylinder lens diffraction, and by Fraunhofer approximation, the analytical expressions of cylinder lens diffraction was given. By setting parameters to calculate and simulate, it was found that to increase the ratio of curvature radius and grating period could effectively reduce the spatial distribution of the diffraction light intensity. For the gratings that already exist, by reducing the ratio of refractive index of the gratings material and environment, the spatial light distribution of the grating could be reduced. If the cylinder grating period is too small, the overlap part of images segmentation light diffraction intensity will increase. But it occupies smaller proportion of the total light intensity. After the optimization design of cylinder grating, the results showed that it could be used for non-contact speed measurement in the range of some parameter.

scholarly journals Control of local stress in semiconductor silicon structures

2018 ◽  
Vol 9 (3) ◽  
pp. 254-262
Author(s):  
S. F. Sianko ◽  
V. A. Zelenin
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Local Stress ◽  
Local Deformation ◽  
Residual Stress Distribution ◽  
Semiconductor Structure ◽  
Curvature Radius ◽  
Silicon Structures ◽  
Semiconductor Circuits ◽  
Film Substrate

Residual stress distribution in multilayer semiconductor structure is complicated and has a significant impact on device characteristics and yield, therefore their study is one of the actual tasks of modern device engineering. Purpose of the present work was to develop methods of estimation of actual residual stress distribution at the whole area of semiconductor structure and its elements as well.The estimation of residual stress distribution at the area of semiconductor structure was carried out on the basis of determining of local deformation of some areas of the structure by Makyoh topography. This method is based on consequent measurements of intensity of Makyoh image elements of the structure along the chosen direction followed by calculation of micro-geometrical profile and curvature radius.The estimation of residual stress of topological elements Si–SiO system was carried out by means of calculation of interference pictures obtained in a film-substrate gap after separating of film edge from substrate along open window perimeter.Analytical expressions relating semiconductor structure image characteristics with their deformation were developed by means of finite elements method. The expressions allow determining of local residual stress of chosen area of the structure. The examples of stress calculations in real structures are given.Proposed residual stress calculation methods allow to take into consideration character and curvature form of substrate, and also to estimate their magnitude in real topological elements of semiconductor circuits.

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