Defect Inspection Wafer Notch Orientation and Defect Detection Dependency

Defect detection and defect control are crucial for yield improvement in semiconductor industry. A discrepancy between detected defects compared to yield data regarding a common defect type was found. Historical data show a different behavior was seen on different product groups. A product design analysis on affected layer shows a striking difference in the Terminal Metal Layer (TML) line orientation between those product groups. A particle deposition system was used to distribute a fixed number of PSL spheres on to wafers prior etch process and defect inspections with different wafer notch orientations were performed at the final step. Those deposited PSL spheres prior etch process resulted in extra pattern defects at the inspection step. Extra pattern defects were mostly detected using a certain wafer notch orientation recipe to the majority of TML line orientation compared to the other one. This case study discusses the influence of a defect inspection wafer notch orientation to the defect capture rate on TML layer. Based on this result, the industry should consider the majority line orientation of respective layer on each inspection step when creating a new defect scanning recipe, especially for TML layer.

Experimental Investigation on the Axially Loaded Performance of Notched Hexagonal Concrete-Filled Steel Tube (CFST) Column

This study aimed to investigate the static performance of notched hexagonal concrete-filled steel tube (CFST) stub columns through axial loading. Notch length, notch location, and notch direction in 14 CFST stub columns were experimentally studied. Stress process, failure mechanism, and ultimate strength in the notched CFST columns were analyzed. Results show that notches in steel tubes can weaken the restraining effect of steel pipes on core concrete and induce a decrease in the ultimate strength of specimens. The failure mode of components is greatly affected by notch orientation. The notch is closed under axial compression in the horizontally notched specimen, and the slotting indicates outward buckling in the vertically notched specimen. Based on the test results, a method for calculating the ultimate strength of notched hexagonal CFST columns was established. This research encourages the extensive application of these structures in civil engineering.

Experimental Study on Bi-Axial Mechanical Properties of Warp-knitted Meshes with and without Initial Notches

Warp-knitted meshes have been widely used for structural reinforcement of rigid, semi-rigid, and flexible composite materials. In order to meet the performance requirements of different engineering applications, four typical warp-knitted meshes (rectangular, square, circular, and diamond) were designed and developed. The mechanical behaviors of these meshes under mono-axial and multi-axial tensile loads were compared. The influence of the initial notch length and orientation on the mechanical performance was also analyzed. The results showed that the biaxial tensile behavior of warp-knitted meshes tended to be more isotropic. The anisotropy level of the diamond warp-knitted mesh was the lowest (λ = 0.099), while the rectangular one was the highest (λ = 0.502). The notch on a significantly anisotropic mesh was propagated along the direction of larger modulus, while for a not remarkably anisotropic mesh, notch propagation was probably consistent with the initial notch orientation. The breaking strength of warp-knitted meshes with the same initial notch orientation decreased with the increase in notch length in both the wale and course directions. For warp-knitted meshes with the same initial notch length, the breaking strength in the wale direction was kept stable at different notch orientations, while that in the course direction decreased remarkably with notch orientation from 0° to 90°.

Fracture Toughness of Different Locations in API X80 Pipeline Steel on Low Constraint SENT Specimens

With the considerable use of high-grade pipeline steel in onshore and offshore project, welded joints are recognized as the weak link in pipeline because of the non-uniform microstructural regions induced by welding heat input. At first, the microstructural of different regions in API X80 pipeline welded joints was characterized and quantified by SEM, which indicate that the pipeline steel is a typical acicular ferrite steel. In this paper we investigated the J-integral resistance curve (J-R curve) in different locations of API X80 pipeline welded joints through low constraint SENT specimens with side grooves at room temperature. The effect of notch orientation (longitudinal-radial (L-R) and transverse-radial (T-R)) on resistance curve were investigated in base metal, which reveal the orientation almost have no effect on resistance curve. As the welded joints adopted in this study is two-pass steel arc welds, so the J-R curves of the inner surface, the outer surface and through-thickness surface notches specimens in the weld metal were investigated. The inner surface sample have the highest toughness through three samples because of the effect of second pass welding process. The effect of constraint on resistance curve was conduct between low constraint SENT specimen and high constraint SENB specimen, which found that the lower constraint corresponding to the higher resistance curve. After finishing the test, crack advancing plan of different positions were etched and observed by OM to demonstrate that the crack path always in the region which we would like to test.

Effect of TiO2 and ZnS Fillers on the Bending Characteristics of GFRP Composites under Varied Flaw Configurations

In the present work an attempt has been made in order to investigate the bending strength and flextural strength of the TiO2 and ZnS filled Glass Fabric Reinforced Polymer (GFRP) composites. The volume fractions in the matrix were chosen as 1, 2 and 3%. The effect of notch orientation on interlaminar and translaminar bending characteristics has been evaluated and Bending strength has been evaluated for specimens with edge cracks with varied crack lengths. The results have showed that, the addition of filler up to 2 vol% has increased the strength of the composite and ZnS as filler is preferred over TiO2.