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Solution-based processes have received considerable attention in the fabrication of electronics and sensors owing to their merits of being low-cost, vacuum-free, and simple in equipment. However, the current solution-based processes either lack patterning capability or have low resolution (tens of micrometers) and low pattern fidelity in terms of line edge roughness (LER, several micrometers). Here, we present a surface energy-directed assembly (SEDA) process to fabricate metal oxide patterns with up to 2 orders of magnitude improvement in resolution (800 nm) and LER (16 nm). Experiment results show that high pattern fidelity can be achieved only at low relative humidities of below 30%. The reason for this phenomenon lies in negligible water condensation on the solution droplet. Employing the SEDA process, all-solution-processed metal oxide thin film transistors (TFTs) are fabricated by using indium oxide as channel layers, indium tin oxide as source/drain electrodes and gate electrodes, and aluminum oxide as gate dielectrics. TFT-based logic gate circuits, including NOT, NOR, NAND, and AND are fabricated as well, demonstrating the applicability of the SEDA process in fabricating large area functional electronics.

As an important optical component in laser system, silicon mirror surface is required to have micron-level flatness and subnanometer-level roughness. The research concentrates on how to improve roughness as far as possible while maintaining flatness of silicon mirror surface during chemical mechanical polishing (CMP) process. A polishing edge effect model is established to explain the reason of flatness deterioration, and a roughness theoretical model is set up to get the limit of perfect surface roughness. Based on the models above, a polishing device is designed to maintain the surface flatness, and the optimized polishing process parameters are obtained by orthogonal tests to get a near-perfect surface roughness. Finally the maintenance of flatness and the improvement of roughness can be achieved at the same time in one step of CMP process. This work can be a guide for silicon mirror manufacture to improve optical reflection performance significantly.

Marangoni drying is a highly concerned technology in the integrated circuit (IC) manufacturing, which removes the deionization (DI) water on the wafer surface in the wet cleaning process after chemical mechanical polishing (CMP). When the wafer is withdrawn from a DI water bath, Marangoni effect is induced by the organic vapor blown at the meniscus. It contributes to the backflow and stripping of the entrained water on the wafer and then achieves an ultraclean surface. Herein, the Marangoni drying performance is experimentally investigate using a self-developed drying device. Firstly, the visible water film on the wafer surface before and after Marangoni drying is observed. It indicates that Marangoni effect dramatically increases the critical withdrawal velocity where the visible water is formed. Further, the fluorescent particles are added in DI water, and the drying performance is characterized by counting the deposited particles using a fluorescent microscope. Such a method indirectly reflects the drying performance. The experimental results show that withdrawal velocity, organic vapor flux and blown angle exert significant impacts on the drying performance.

Edge rolling plays a vital role in width control of strip rolling, where plastic deformation concentrates in the edge of the slab. Then, the center of the slab remains its initial shape. The local deformation is different from overall one which obtained in horizontal rolling. In this paper, dog-bone shape is creatively described by a continuous symmetric parabola used to describe, and based on the complex mathematical function, a kinematically admissible continuous velocity field for edge rolling is established. Finally, the upper deformation power function is yielded. Based on minimum of the power, the results in edge rolling force and torque are obtained. Some vertical rolling forces for copper and aluminum experiments are calculated by the function, and then, also the results are verified by the traditional models. Anyway, the maximum error is less than 18 %. This is a crossover study on both mathematical curve and mechanical analysis which can be seen as a combination of the theory and engineering.

The Marangoni effect induced by organic vapor has drawn considerable attention in integrated circuit manufacturing for eliminating watermark defects encountered in the wafer drying process. Accordingly, a vertical rotational Marangoni (VRM) dryer based on the combination of the Marangoni effect and centrifugal force is proposed and developed. In particular, the hydrodynamic behavior of the VRM dryer is investigated to reveal the mechanism of ultraclean drying. A three-dimensional model of the VRM dryer is proposed, and the flow field of the water film and distribution of organic species are adequately analyzed. The results show that the rotational velocity and wettability significantly affect the coverage uniformity of the water film, and the exposure region at the three-contact line leads to the watermark. Furthermore, the coupling behavior of the Marangoni effect and centrifugal force is revealed. A higher rotational velocity leads to worse integrity of the water film covering, and thus, fainter Marangoni effect. Polishing and cleaning experiments are conducted to verify the effectiveness of theoretical analysis. The results indicate that the optimized rotational velocity for the hydrophilic surface is higher than that of the hydrophobic surface. The mechanism analysis of wafer drying based on the VRM drying technology provides effective guidance for ultraclean surface manufacturing during the cleaning process.

Cleaning processes draw considerable attention in integrated circuit manufacturing because of the rapid development of technology nodes. Bare silicon wafer cleaning after chemical mechanical polishing (CMP) is one of the most difficult processes used to meet the extremely strict industrial requirements. Herein, the silicon wafer cleaning mechanism is studied in detail. The effects of megasonic and brush cleaning on nanoparticle removal are both analysed through experiments and simulations. The experimental results show that chemical concentration, megasonic vibration power, and brush clamp gap all significantly affect the cleaning performance, and that excessive megasonic power reduces the cleaning performance because more defects are introduced. A model of megasonic nozzle trajectory is also proposed, and optimized parameters, especially the relative velocity between the wafer rotation and nozzle movement, are critical to removing nanoparticles effectively. Furthermore, analysis of combining megasonic and brush cleaning shows that including megasonic cleaning improves the wafer cleaning performance by several orders of magnitude. Based on the optimized cleaning conditions, an ultraclean wafer surface is achieved after CMP.

Nanoparticle movement near a surface is greatly influenced by electrostatic and Van der Waals forces between the particle and the surface, as well as by Brownian motion. In this paper, several precise equations are derived to describe the Van der Waals and electrostatic forces between a particle and a surface when the particle is removed from the surface. These include an equation for particle displacement under the electrostatic force, and a numerical calculation for particle displacement under the Van der Waals force. Finally, a kinematic model is constructed to describe the particle distribution under the effects of the electrostatic and Van der Waals forces, as well as the particle’s Brownian motion. The results show that increasing the multiply of the particle and surface zeta potential values and decreasing the ionic strength of the detergent can prevent a particle from redepositing onto a surface.

For several decades, chemical mechanical polishing (CMP) has been the most widely used planarization method in integrated circuits manufacturing. The final polishing results are affected by many factors related to the carrier structure, the polishing pad, the slurry, and the process parameters. As both chemical and mechanical actions affect the effectiveness of CMP, and these actions are themselves affected by many factors, the CMP mechanism is complex and has been a hot research area for many years. This review provides a basic description of the development, challenges, and key technologies associated with CMP. We summarize theoretical CMP models from the perspectives of kinematics, empirical, its mechanism (from the viewpoint of the atomic scale, particle scale, and wafer scale), and its chemical-mechanical synergy. Experimental approaches to the CMP mechanism of material removal and planarization are further discussed from the viewpoint of the particle wear effect, chemical-mechanical synergy, and wafer-pad interfacial interaction.

A wear-resistant steel was hot rolled at the same finish temperature, and subsequently treated with conventional reheat quenching and tempering process (RQ&T) and direct quenching and tempering process (DQ&T), respectively. The effect of direct quenching on the microstructure and mechanical properties was investigated in detail by using optical microscope, transmission electron microscope and scanning electron microscope equipped with electron backscattered diffraction. The results showed that the microstructures of both the RQ and DQ specimens were complex constituents of lath martensite and lower bainite. Compared with the RQ specimen, the lower bainite content in DQ specimen was much higher. Furthermore, the bainite in the DQ specimen extended into and segmented the prior austenite grains, which can decrease martensite packet size. The proportion of high-angle boundary in the DQ specimen was higher than that in the RQ specimen, which may improve the impact toughness. The carbides in DQ&T specimen were much finer and distributed even dispersively because direct quenching can retain substantive defects which may provide more nucleation sites for carbide precipitation in the tempering process. Besides, the mechanical properties of DQ and DQ&T specimens were superior than those subjected to RQ and RQ&T processes, respectively.

A finite element analysis (FEA) model is developed for the chemical-mechanical polishing (CMP) process on the basis of a 12-in five-zone polishing head. The proposed FEA model shows that the contact stress non-uniformity is less dependent on the material property of the membrane and the geometry of the retaining ring. The larger the elastic modulus of the pad, the larger contact stress non-uniformity of the wafer. The applied loads on retaining ring and zone of the polishing head significantly affect the contact stress distribution. The stress adjustment ability of a zone depends on its position. In particular, the inner-side zone has a high stress adjustment ability, whereas the outer-side zone has a low stress adjustment ability. The predicted results by the model are shown to be consistent with the experimental data. Analysis results have revealed some insights regarding the performance of the multi-zone CMP.

Microstructural characteristics of different sub-regions of heat affected zone (HAZ) of low welding crack susceptibility steel weldment were investigated by using optical microscopy and scanning electron microscopy equipped with electron backscattered diffraction system. And the focus was put on the correlation between microstructural characteristics and HAZ toughness of the weldment. The results reveal that the toughness of fusion line zone (FLZ) specimens is much lower than that of fine grained HAZ (FGHAZ) specimens. The coarse inclusions in the weld metal and the large martensite-austenite constituents in the coarse grained HAZ (CGHAZ) have an obvious negative effect on the crack initiation energy of FLZ. Meanwhile, the coarse granular bainite with large effective grain decreases the crack propagation energy seriously. By contrast, fine crystallographic grains in the FGHAZ play a key role in increasing toughness, especially in improving crack propagation energy.

In this paper, an in-situ interfacial fluid pressure measurement system had been developed for 12'' CMP equipment. Using this system, the interfacial fluid behavior is studied during the polishing process of 12-inch silicon wafer. The effects of the basic polishing variables, including the slurry injection position, the down force, the rotational speed, and the slurry flow rate, on the fluid pressure are investigated systematically. The results suggest that all of these polishing variables have obvious effects on the fluid pressure: the slurry injection position with suitable center distance between the pad and angular distance to the wafer leading edge is good for uniform slurry dispersion and the fluid pressure building; the increasing down force can increase the ratio of the positive pressure and the average fluid pressure significantly; the fluid pressure increases with the rotational speed till a critical speed and then decreases; the fluid pressure increases with the slurry flow rate slightly, the slurry injection position with larger center distance has lower critical speed and has greater dependence on the slurry flow rate due to the lower slurry utilization efficiency caused by larger centrifugal spraying effect.

In this paper, a novel in-situ interfacial fluid pressure measurement system is developed for the practical chemical mechanical polishing (CMP) equipment, in which the pressure sensors are equidistantly embedded in the platen along the radial direction and sweep beneath the wafer surface during CMP. Interfacial fluid pressure mapping is realized for standard 12'' blanket wafers at the down pressure of 0.5 [?] 2.0 psi. The fluid pressure profiles from the leading edge to the trailing edge and the pressure contour maps of the fluid film across the whole wafer surface are constructed and displayed. Results reveal a large positive pressure region located near the wafer trailing edge and a small negative pressure region located near the leading edge, which is quite different from the negative dominated results of previous studies. The fluid pressure can support 15% [?] 30% of the applied pressure. The down pressure has great effect on the fluid pressure due to the wafer's bend under the applied load. When the down pressure increases, the positive pressure region expands and slightly shifts toward the outer of the pad while the negative pressure region shrinks.

In this study, two API X80 pipeline steels were fabricated by varying Ti additions, and their microstructures and fracture characteristics were analyzed to investigate the effects of Ti-enriched carbonitride on the tensile properties and Charpy impact properties. Lathy bainite, a mass of matensite/austenite (M/A), coarse cubic Ti-enriched inclusions, chain-typed Ti-enriched precipitations, weak toughness and high tensile strength were found as consequences of higher amount of Ti content. Those large scale and chain-typed Ti-enriched car-bonitrides are one kind of crack sources during fracture. The negative effect of higher amount of Ti on the impact properties is increased with decreased temperature. [ABSTRACT FROM AUTHOR]

Wafer drying induced by Marangoni effect is crucial to achieving an ultraclean surface in integrated circuit manufacturing. According to the previous opinions, the entrained water film on wafer surface was stripped by Marangoni effect, and thus the watermark defect induced by evaporation was inhibited. However, the influence of particle removal induced by Marangoni effect on the ultraclean surface preparation is lack of adequate understanding. The present work implements an experimental and numerical investigation of wafer cleaning behavior engendered by Marangoni effect during the wafer withdrawn process. The impacts of critical process parameters and substrate properties on the particle removal efficiency are systematically studied. The results show that Marangoni effect has better cleaning performance on the glass substrate compared with that of silicon and copper. The numerical simulation indicates that the Marangoni effect is more dramatic on glass substrate owing to the better wettability. Furthermore, the stress analysis reveals the adsorption force of fluorescent particle on the copper surface is stronger than that of silicon and glass. Therefore, particle cleaning on the copper surface is much more difficult. The investigation of cleaning performance driven by the Marangoni effect will contribute to a comprehensive understanding of the mechanism of ultraclean surface preparation.

Wafer drying induced by Marangoni effect is crucial to achieving an ultraclean surface in integrated circuit manufacturing. According to the previous opinions, the entrained water film on wafer surface was stripped by Marangoni effect, and thus the watermark defect induced by evaporation was inhibited. However, the influence of particle removal induced by Marangoni effect on the ultraclean surface preparation is lack of adequate understanding. The present work implements an experimental and numerical investigation of wafer cleaning behavior engendered by Marangoni effect during the wafer withdrawn process. The impacts of critical process parameters and substrate properties on the particle removal efficiency are systematically studied. The results show that Marangoni effect has better cleaning performance on the glass substrate compared with that of silicon and copper. The numerical simulation indicates that the Marangoni effect is more dramatic on glass substrate owing to the better wettability. Furthermore, the stress analysis reveals the adsorption force of fluorescent particle on the copper surface is stronger than that of silicon and glass. Therefore, particle cleaning on the copper surface is much more difficult. The investigation of cleaning performance driven by the Marangoni effect will contribute to a comprehensive understanding of the mechanism of ultraclean surface preparation.

Marangoni drying is a highly concerned technology in the integrated circuit (IC) manufacturing, which removes the deionization (DI) water on the wafer surface in the wet cleaning process after chemical mechanical polishing (CMP). When the wafer is withdrawn from a DI water bath, Marangoni effect is induced by the organic vapor blown at the meniscus. It contributes to the backflow and stripping of the entrained water on the wafer and then achieves an ultraclean surface. Herein, the Marangoni drying performance is experimentally investigate using a self-developed drying device. Firstly, the visible water film on the wafer surface before and after Marangoni drying is observed. It indicates that Marangoni effect dramatically increases the critical withdrawal velocity where the visible water is formed. Further, the fluorescent particles are added in DI water, and the drying performance is characterized by counting the deposited particles using a fluorescent microscope. Such a method indirectly reflects the drying performance. The experimental results show that withdrawal velocity, organic vapor flux and blown angle exert significant impacts on the drying performance.

In this paper, an in-situ interfacial fluid pressure measurement system had been developed for 12″ CMP equipment. Using this system, the interfacial fluid behavior is studied during the polishing process of 12-inch silicon wafer. The effects of the basic polishing variables, including the slurry injection position, the down force, the rotational speed, and the slurry flow rate, on the fluid pressure are investigated systematically. The results suggest that all of these polishing variables have obvious effects on the fluid pressure: the slurry injection position with suitable center distance between the pad and angular distance to the wafer leading edge is good for uniform slurry dispersion and the fluid pressure building; the increasing down force can increase the ratio of the positive pressure and the average fluid pressure significantly; the fluid pressure increases with the rotational speed till a critical speed and then decreases; the fluid pressure increases with the slurry flow rate slightly, the slurry injection position with larger center distance has lower critical speed and has greater dependence on the slurry flow rate due to the lower slurry utilization efficiency caused by larger centrifugal spraying effect.

In this paper, a novel in-situ interfacial fluid pressure measurement system is developed for the practical chemical mechanical polishing (CMP) equipment, in which the pressure sensors are equidistantly embedded in the platen along the radial direction and sweep beneath the wafer surface during CMP. Interfacial fluid pressure mapping is realized for standard 12″blanket wafers at the down pressure of 0.5 ∼ 2.0 psi. The fluid pressure profiles from the leading edge to the trailing edge and the pressure contour maps of the fluid film across the whole wafer surface are constructed and displayed. Results reveal a large positive pressure region located near the wafer trailing edge and a small negative pressure region located near the leading edge, which is quite different from the negative dominated results of previous studies. The fluid pressure can support 15% ∼ 30% of the applied pressure. The down pressure has great effect on the fluid pressure due to the wafer's bend under the applied load. When the down pressure increases, the positive pressure region expands and slightly shifts toward the outer of the pad while the negative pressure region shrinks.