Many Types Of Defects Research Articles

A Novel Defect Inspection Method for Semiconductor Wafer Based on Magneto-Optic Imaging

The defects of semiconductor wafer may be generated from the manufacturing processes. A novel defect inspection method of semiconductor wafer is presented in this paper. The method is based on magneto-optic imaging, which involves inducing eddy current into the wafer under test, and detecting the magnetic flux associated with eddy current distribution in the wafer by exploiting the Faraday rotation effect. The magneto-optic image being generated may contain some noises that degrade the overall image quality, therefore, in this paper, in order to remove the unwanted noise present in the magneto-optic image, the image enhancement approach using multi-scale wavelet is presented, and the image segmentation approach based on the integration of watershed algorithm and clustering strategy is given. The experimental results show that many types of defects in wafer such as hole and scratch etc. can be detected by the method proposed in this paper.

Numerical modelling crack propagation under Mode II fracture in plain concretes containing siliceous fly-ash additive using XFEM method

Many types of defects occurs in complex concrete materials. Therefore one can use various theoretical micro-crack models to simulate real behaviour of such materials. In order to apply any model it is necessary to carry out proper experiments to estimate fracture toughness for Modes I and II, to be able to perform simulation of the material response.For experiments we used structural concretes containing siliceous fly-ash additives. Mode II fracture toughness for fictitious cracks and their development was carried out using specimens for two concrete mixtures: (a) concrete without siliceous fly-ash (FA), (b) concrete with 20% FA additive. Compact Shear Specimens (CSSs) – 150×150×150 concrete cube with two fictitious cracks were used for tests under quasi-static loading.A new 3-D numerical model for CSS used for experimental testing of the Mode II fracture was created using XFEM. In calculations we used peak principal stress criterion for description of the crack grow, taking into account own experimental data concerning strength and fracture mechanics parameters. The calculated results with the newly formulated 3-D CSS numerical model coincide with experimental tests very well. There was a convergence of: cracks shapes, FQ, critical force values that enabled initial crack development and force–displacement graphs.

The Association Analysis of TBX6 Polymorphism With Susceptibility to Congenital Scoliosis in a Chinese Han Population

A case-control association study was conducted to investigate the genetic etiology for congenital scoliosis (CS) in a Chinese Han population. To identify whether TBX6 polymorphisms are associated with susceptibility to CS in a Chinese Han population. CS is a 3-dimensional deformity of the spine, resulting from defection of normal vertebral development. Although there are many types of defects observed in CS, all result from abnormal formation and segmentation of the vertebral precursors, called somites. Developmental studies in animal models have identified many genes regulating somite formation and segmentation. T-box factor, TBX6, is a prerequisite for somite segmentation in vertebrates. In mouse TBX6 knockouts, the phenotypes are similar with that of some human birth defects, such as CS, raises the possibility that TBX6 gene may be a potential susceptibility gene for CS, so we investigated the relations between TBX6 polymorphisms and CS. Two known single-nucleotide polymorphisms (SNPs) of TBX6 gene were genotyped among 254 Chinese Han subjects (127 CS patients and 127 controls with matched sex and age) by GenomeLab SNPstream genotyping system. The 2 markers (the only tagging SNP and a functional SNP) with minor allele frequency above 5% were analyzed by the allelic and genotypic association analysis, the genotype-phenotype (CS patients were divided into type I 31 cases [failure of formation], type II 46 cases [a failure of segmentation], and type III 50 cases [mixed defects]) association analysis, and the haplotype analysis. The single SNP analysis showed allele frequency of rs2289292 (exon 8, the only tagging SNP) and rs3809624 (5' untranslated region) demonstrated significant difference between CS cases and controls (P = 0.017 and P = 0.033). No SNP was found to be correlated with clinical phenotype. Moreover, the 2 makers (rs2289292 and rs3809624) in TBX6 gene were found to be in strong linkage disequilibrium (D' = 1.0; gamma = 0.984; 95% confidence interval, 0.96-1.0; LOD = 57.48) in the controls. Both global haplotype analysis and individual haplotype analysis showed that the haplotype of SNP1/SNP2 showed significant association with the disease (P = 0.017), G-A haplotype was more frequently observed in controls than in cases (odds ratio, 0.71; 95% confidence interval, 0.51-0.99). This is the first report on SNPs of TBX6 gene in CS that suggests genetic variants of TBX6 gene is associated with CS and may play an important role in mediating susceptibility to developing CS in the Chinese Han population.

Opals: Status and Prospects

The beauty of opals results from a densely packed, highly ordered arrangement of silica spheres with a diameter of several hundred nanometers. Such ordered nanostructures are typical examples of materials called photonic crystals, which can be formed by known microstructuring methods and by self-assembly. Opals represent a self-assembly approach to these structured media; such an approach can lead to novel materials for photonics, photocatalysis, and other areas. Although self-assembly leads to many types of defects, resulting in the surprising and very individual appearance of natural opals, it causes also difficulties in technological applications of opal systems.

FPD용 컬러 필터의 수지 얼룩 결함 형상화에 관한 연구

Detecting defects on FPD (Flat Panel Display) color filter before the full panel is made is important to reduce the manufacturing cost. Among many types of defects, the low contrast blemish such as Suzi Mura is difficult to detect using standard CCD cameras. Even skilled inspectors in the inspection line can hardly identify such defects using bare eyes. To overcome this difficulty, point spectrometer has been used to analyze the spectrum to differentiate such defects from normal color filters. However, scanning ever increasing-size color filters by a point spectrometer takes too long time to be used in real production line. We propose a system using a spectral camera which can be viewed as a line scan camera composed of an array of point spectrometers. Three types of lighting system that exhibit different illumination spectrums are devised together with a calibration method of the proposed spectral camera system. To visualize the defect areas, various processing algorithms to identify and to enhance the small differences in spectrum between defective and normal areas are developed. Experiments shows 85% successful visualization. of real samples using the proposed system.

Modeling of Fluid Flow and Heat Transfer in Twin-Roll Casting of Aluminum Alloys

A two-dimensional finite element based mathematical model of coupled turbulent fluid flow, heat transfer, and solidification in horizontal twin-roll thin strip casting was developed. Basic formulations for simulating the coupled thermal and flow fields are described in this paper. A k-e turbulence model was used to calculate the turbulent viscosity in the melt pool. A variable viscosity model was used to model the mushy region. Inlet velocity, strip/roll heat transfer coefficient, alloy composition, and melt superheat were the main process variables considered. The effect of the above process variables on the sump depth, mean strip exit temperature, roll surface temperature, and temperature gradients inside the roll, was analyzed. Twin-roll thin strip casting of aluminum alloys, is an ef- ficient way of obtaining hot-rolled strips directly from the molten metal. In this process, the molten metal is fed from a refractory feed tip into the gap between the steel rolls. The material undergoes a considerable amount of hot rolling be- fore it leaves the rolls. The heat is extracted from the melt by the water-cooled rolls. The process involves solidification of liquid metal and rolling of solidified metal before it leaves the kissing point, which is the point of least roll separation, of the two rollers. Solidification of molten metal starts at the point of first metal-roll contact and is over before the kissing point. The process has many advantages over the conventional casting technique. The primary advantages are of reduced number of steps of operation and very high cooling rates. A very high cooling rate provides microcrystalline structure with improved mechanical properties. But the process also suffers from many types of defects in the cast strip, which is pronounced at higher casting speeds and inlet temperatures. Increasing the casting speed leads to an increase in the mean exit strip temperature and thus rolling force decreases. 1) The major defects encountered are the centerline segregation, heat line formation, sticking, and surface cracks due to the induced thermo-mechanical stresses. Extent or the severity of these defects is very sensitive to the process conditions. Proper op- timization of these process conditions can lead to minimiza- tion of these defects. Hence, a detailed analysis of fluid flow and heat transfer is necessary to find the effect of these vari- ous process parameters on the extent of these defects. Various mathematical models 2-7) have been suggested in the literature to predict the fluid flow, heat transfer, and so- lidification in twin-roll casters. Most of the papers deal with fluid flow modeling in vertical twin-roll casters, but only a few papers 6, 7) deal with the fluid flow modeling in horizon- tal twin-roll casters. Miyazawa and Szekely 2) were the first

Thermal Conductivity of Diamond Films: 0.5 μm to 0.5 mm

AbstractA review of the thermal properties of chemical‐vapor‐deposited (CVD) diamond ranging in thickness from 0.5 μm to 0.5 mm is presented. The typical columnar microstructure of the material has a strong influence on the thermal properties, causing a steep gradient in both the in‐plane (κ‖) and normal (κ⊥) conductivities, as well as considerable anisotropy. Data for κ‖ from above room temperature down to liquid helium temperatures for high‐quality thick samples has revealed several types of phonon scattering centers preferentially located along grain boundaries. This model of dirty grain boundaries provides a framework for understanding the conductivity of thinner, lower‐quality material. The general difficulty of identifying microscopic sources of thermal resistance in CVD diamond is discussed, especially in view of the tendency for the concentrations of many types of defects to be highly correlated with each other. Finally, recent work on interfacial resistance between CVD diamond and Si substrate shows that the columnar microstructure has a strong influence for high‐quality films as thin as 2 μm.

The use of echocardiography in pediatric interventional cardiac catheterization procedures.

The last decade saw a dramatic change in the management of congenital heart defects. The introduction and development in echocardiography and Doppler modalities enable definitive diagnosis of congenital lesions without cardiac catheterization. At the same time, new therapeutic procedures for congenital defects using the catheter as a channel for different procedures were developed. These therapeutic procedures have replaced cardiac surgery in many types of defects. The new developments in echocardiography and Doppler modalities provide accurate imaging and visualization of the transcatheter devices and brought these two imaging modalities into a close marriage. The use of echocardiography and Doppler in the catheterization laboratory became a must, especially when used in atrial (ASD) and ventricular septal defect (VSD) closure. In this article we will detail the role of echocardiography in the different transcatheter interventional procedures in the catheterization laboratory. Those include atrial septostomy, blade atrial septectomy, balloon dilation, ASD closure, VSD closure, patent ductus anterior closure, and pericardiocentesis.

Digital IC device testing by transient signal analysis(TSA)

The Letter presents a new approach to testing digital circuits that uses the variations in the transient signals generated within digital circuits as a defect detection method. The IDD transients on the supply rails and voltage transients at selected test points are sampled over a test interval. Simulation experiments show that variations in the transient waveforms between defective and nondefective circuits exist and that these variations are sensitive to many types of defects even when they appear on off-sensitised paths. These variations can be analysed using pattern recognition techniques, and neural processing is proposed as the means of identifying the transient waveforms of defective devices .

Integration of chemical-mechanical polishing into CMOS integrated circuit manufacturing

Planarization by chemical-mechanical polishing (CMP) has been exploited by IBM in the development and manufacture of CMOS products since 1985. Among the products that use this technology are the 4-Mbit DRAM (which uses polysilicon, oxide, tungsten-line and tungsten-stud planarization) and its logic family (which uses four oxide and four tungsten-stud planarization steps). CMP is also used in the planarization of oxide shallow isolation trenches, as in the 16-Mbit DRAM. Reduced sensitivity to many types of defects is possible with CMP. A wafer that is truly flat is easier to clean, eliminates step coverage concerns, provides for better photolithographic and dry etch yields, and generally minimizes complications from prior level structures. Oxide CMP reduces sensitivity to certain pre-existing defects, such as crystalline inclusions or foreign material in an interlevel dielectric. Metal CMP can reduce the incidence of intralevel shorts relative to conventional RIE processing. Random defects associated with CMP, such as slurry residues and mechanical damage, are controlled by careful optimization of the post-polish clean and of the polish process itself. Systematic defects, such as incomplete planarization over very large structures, are controlled by process optimization and prudent design limitations. These include such things as constraints on the image size, the distance between images, and/or the local pattern density. Since its introduction in the 4-Mbit DRAM, there has been a steady increase in the use of chemical-mechanical polishing in IBM CMOS products. The number of steps, processes and materials polished continue to rise, both in current and planned future products. Individual applications range from the simple removal of back-side films to complex insulator or metal planarization requiring high removal uniformity. The process tolerances delivered by CMP have decreased faster than image size, even in the face of dramatic increases in circuit and layout complexity. CMP tools are installed in IBM semiconductor manufacturing and development sites worldwide. Chemical-mechanical polish processes and applications provide unique leverage to IBM products, and are a crucial part of both current and planned IBM CMOS technologies.

Effect of Thermal ramping rate on defect formation in oxygen-implanted silicon-on-insulator material

Integrated circuits on SIMOX (Separation by IMplantation of OXygen) have higher speed, radiation hardness, and higher temperature capability. Defects in the top Si layer inhibit bipolar applications and may affect CMOS(Complementary Metal-On-Semiconductor) device yield, operation and reliability. As-implanted SIMOX has many types of defects, including short stacking faults(SFs), multiply faulted defects(MFDs), and {113} defects. In annealed SIMOX, new defects form during the ramping cycle. The effect of thermal ramping rate on the development of new defects has received only limited study. In this work, the effects of rapid thermal annealing(RTA) and thermal ramp rate on defect density and structural change were studied.Two set of samples were prepared with different oxygen doses. First, one set of (100) Si wafers was implanted with a high dose of 1.8×l018cm−2 at 200 KeV at 620°C. A rapid thermal anneal(RTA) wafer was obtained from a lamp anneal for 1 minute at 1320°C using a ramp rate of 50°C/sec. A portion of this sample was then conventionally annealed in a tube furnace for 5 hours at 1320°C. Another set of (100) Si wafers was implanted with a low dose of 3×l015cm−2 at 25°C. Different samples were then annealed at 1250°C for 30 sec using three ramp rates of 50°C/sec, l°C/sec and 0.1°C/sec. Cross-sections of the samples were studied with conventional transmission electron microscopy (CTEM) at 200 KeV.

Plasma coating of surfaces and how to assess and avoid defects

Within the area of surface engineering Plasma Coating has become a very effective process for improving the surface characteristics of engineering components for tribological, thermal/corrosion protection applications etc. Plasma coating techniques vary from high temperature to low temperature operation in vacuum deposition or in open air spraying process and there are a great number of variables in some of these plasma coating techniques and unless the condition is right the coating produced will be defective. There are many types of defects which need to be avoided in Plasma Coating Technology. However, it is not an easy task to assess some of these defects accurately and new assessment techniques are still being developed. In this review paper the types of defects which are usually encountered in Plasma Coating are illustrated in relation to the various assessment techniques currently used by researchers in order to avoid them.

Automatic Detection of Defects among Small Pins Group — Inspection of Connector-Plug Pins by the Use of Image Processing Associated with Neural Network

Summary Some defects among a large number of electronic connector plug pins inserted into a board. being inspected manually today. can be automatized by the proposed system which consists of an image processor associated with Neural Network. Images which are caught by ITV camera is first processed to binary signals. then input to the first layer of the network. which is composed of other 2nd and 3rd layers. each of which is programed by so-called “Back-Propagation” algorithm. The network learns many types of defects in advance and decides a strength of each net. with which compares the actual image of pins. Fundamental features of the proposed system was made clear and the network could well detect such defects as bended, buckled and mis-positioned pins.

木材表面欠点の自動検出と識別の基礎研究

There are many types of defects in wood, some of which reduce strength of structure parts or spoil the appearance of furniture parts. To make efficient use of valuable wood free from such defects, it is desired to develop an automated inspection system which is able to locate the position and extent of each defect present and to identify the type of defect at each location. In this paper, we propose an automatic inspection method to detect and discriminate surface defects in wood. The essential points of the method are as follows : Input gray level image of testing wood is divided into a number of regions and several tonal property measures are extracted from image of each region, and fuzzy clustering technique is adopted for detection and discrimination of surface defects. Applying the proposed method to inspection tests of actual lumbers, we obtained the following results : (1) Defect detection can be achieved almost completely. (2) Discrimination rate ranges from 25 to 82% depending on the type of defect, and this indicates that more research is needed.

Detection of defects on the surface of microelectronic structures

Many types of defects on photolithographic masks can be detected by using only local pattern properties specified by general design rules. No comparison between adjacent chip images or an external data base is required, eliminating the need for high metrological precision. A number of detection criteria such as local deviations from straightness or admissible contour angles were tested on simulated images containing various defect types. Usable algorithms that could be implemented as high-speed circuits permitting data throughputs at TV rates are discussed. >

Aem analysis of defects in processed Si wafers

The analytical electron microscope is particularly well suited for the characterization of many types of defects observed in semiconductor materials. One type of common defect which has been shown to occur in some devices is an electrically-active rod defect which has a detrimental effect on some properties. In the present AEM investigation Si devices which exhibited a significant degradation in certain electrical properties (excess junction leakage) were examined in order to ascertain the cause of this phenomenon.The starting material in the process was n-type (100) silicon wafers. The initial processing step was the growth of 200nm of LPCVD SiO2. During the processing sequences wafers were subjected to temperatures up to 900°C.