Papers by Keyword: Wetting

Abstract: In advanced semiconductor manufacturing, deep hydrophilic nanoholes are found in various applications, which require a wet clean after patterning. In this work, we use an in-situ ATR-FTIR spectroscopy technique to characterize the wetting of nanoholes in a silica matrix by UPW and electrolyte solutions. Wetting was much slower than predicted by a numerical model, while temperature cycling evidenced the formation of unexpectedly stable gas pockets in the wetted nanoholes. Water structuring in the nanoholes was characterized by an analysis of the OH stretching peak. Besides, monitoring the dissolution of CO2 in the wetted nanoholes allowed to compare the diffusivity in the nano-confined solutions with that in bulk solutions. Our results strongly suggest that the gas pockets were stabilized by the decreased gas diffusivity resulting from water structuring.

Abstract: Efficient cleaning of contaminations in the semiconductor industry is a determining factor in ensuring the good quality of the electronics products. We present here the dynamic wetting characterization of a fluid on top of DTI structures using ultra-high frequency acoustic method. The dynamics of the fluid will be established using a PDMS micro-channel placed on top of the structures, in order to obtain conditions as close as possible to those used in the industrial process. Wetting state of the DTI structures is determined based on the measured acoustic reflection coefficient.

Abstract: Performance of the semiconductor devices is solicited by reliable metallic electrical connections. Any bad electrical connection may one of the major sources of noise and low mechanical strength, hence reducing the performance and life of the device. Apart from the successful synthesis or development of semiconductor devices or solders; the technique to carry out soldering process plays a vital role to attain reliable and reproducible electrical connections. This paper demonstrates the soldering process on gold thin films using In-3.0%Ag eutectic soldering alloys considering the three fundamental aspects of the process i.e. scavenging, wetting and aging. Scavenging and wetting behaviors of the solder were evaluated at various temperatures and different fluxes, respectively. Effect of aging was evaluated by shear testing after aging for various durations. It was observed that using the soldering temperature somewhere between 160-190 °C with 20 wt.% salicylic acid flux is favorable for better wetting and scavenging characteristics. A post solder aging (at 95 °C for 12 hours) seamed to facilitate improvement in mechanical strengths.

Abstract: The use of dental implants of titanium and its alloys has proved to be effective, through well established and documented parameters, both in the dimensions and in the manufacturing processes and also in the surgical techniques. There are clinical situations where there is a need to reduce the diameter of the implants, below 3.75 mm in diameter. In the current state of art of the implant technology it is desirable that these also have surfaces capable of decreasing the period of osseointegration. In the present work, to improve the mechanical strength of the material, an alloy of 80% of Ti and 20% of Zr % in mass was proposed and elaborated, aiming its use as biomaterial. Physical, chemical, microstructural and mechanical characterization was carried out. The surfaces of the treated samples were observed using: scanning electron microscopy (SEM); semi quantitatively chemically analyzed using dispersive energy spectroscopy (EDS: wettability of the samples was determined and, finally, the roughness was measured using optical profilometry. For the conditions used in the present work, it was concluded, that the best surface treatment for the TiZr 80/20 alloy was acid etching with 1% vol. hydrofluoric acid for 5 minutes, as this treatment presented the most prominent results of wettability and roughness simultaneously.

Abstract: We present a result of a study of reactive wetting of surface of low carbon steel by liquid alloys CuSnBiPbGa, CuSnBiPbIn and CuSnBiInCd of equiatomic composition. Dependences of contact angle and spot diameter of wetted surface on temperature and time were studied. Liquid alloy CuSnBiPbGa begins wetting of surface of steel at 900 °C; spreading rate at higher temperatures increased by 8 times. Liquid alloy CuSnBiPbIn begins wetting surface of steel at 780°C, but spreading speed is almost unchanged with the further increase in temperature. Liquid alloy CuSnBiInCd begins wetting of surface of steel at a temperature of 570°C, and spreading is in a flash in nature. We studied microstructure and chemical composition of diffusion layers, formed at the spreading of liquid alloys of equiatomic composition CuSnBiPbGa, CuSnBiPbIn and CuSnBiInCd on steel surface. In all experiments at boundary with substrate a ductile transition layer of a solid solution of iron-based is formed. The thickness of diffusion layer side depends on the alloy composition. The widest diffusion layers formed for alloy CuSnBiInCd, and the most narrow - for alloy CuSnBiPbGa. We detected in segregations of copper and gallium atoms for bimetallic sample "CuSnBiPbGa+steel", of copper and tin atoms for samples "CuSnBiPbIn+steel" and "CuSnBiInCd+steel" in diffusion layers. The results of these studies have significance for the design of soldering technology and application of protective coatings on steel products.

Abstract: The article discusses aspects of the production and use of composites based on carbon-filled cement matrices. It is shown that the main problem in the technology of such composites is the regulation of the processes of structure formation and uniform distribution of the electrically conductive phase throughout the volume, to ensure stable electrical characteristics of the material. A method for solving the problem of improving the physical, mechanical and thermal properties of carbon-filled Portland cement composites by regulating the surface properties of carbon fillers, in order to reduce their concentration in the composite and the content of the aqueous phase, is proposed. It is shown that the modification of the carbon filler surface using the water-repellent agent PMS-20 reduces the adhesion work at the interface, which makes it possible to reduce the concentration of the electrically conductive phase in the composite and improve its physical, mechanical and thermal characteristics.

Abstract: The temperature- and time-dependent penetration of surface structures is examined in thermal joining between polypropylene and aluminum. Experimental and numerical investigations were carried out for spot joints in order to describe the main effects on structure penetration. Further investigations were performed in a half-section setup to gain information directly from the joining zone. The thermal expansion of the thermoplastic material as well as the temperature distribution in the melting layer were identified as key parameters for structure filling on the metal surface.

Abstract: This paper is describing an investigation of surfactants influence on zinc sulfide wetting by non-polar liquids and sphalerite concentrates pressure leaching parameters. Zinc sulfide preferential wettability by oil was tested in presence anionic surfactants with different chemical structures. Interfacial tension was determinated by the maximum liquid drop volume method. It allows to determine surfactant potential effectivity on pressure leaching of sphalerite concentrate. It is found that SDBS decreases zinc sulfide wettability by non-polar liquids in a greater degree than SDS and Ls. Combined addition of Ls and SDBS allowed to receive residues with optimal coarseness, eliminate pellet formation and increase zinc extraction.

Abstract: In this paper, a preliminary study in the wetting behavior and interface reaction between active Sn-Ag-4Ti solder alloy and C-plane sapphire was given. An in-situ observation of Sn-Ag-4Ti alloy on C-plane sapphire revealed a decrease in contact angles at temperature close to 550°C. Moreover, sapphire/sapphire and sapphire/copper sandwich joints were brazed using Sn-3.5Ag-4Ti alloy at 500 ^oC, 550°C and 600 °C to investigate the microstructure evolution and interface reaction. Microstructure characterization and element analysis indicated that the temperature affected the diffusion of active Ti element by modifying the formation of Sn-Ti intermetallics compounds in Sn-Ag-Ti solder alloy. The absorption of Ti together with the release of Al from sapphire suggested the interface reaction between Sn-Ag-Ti alloy and sapphire was triggered at 550°C.

Abstract: Interfacial behavior of Al and α-Al₂O₃ are investigated via molecular dynamic simulation (MD) employing reactive force fields parameterized for Al and Al₂O₃. The main result of this work is elucidating the wetting behavior and interface chemistry of molten aluminum on the α-Alumina (0001) surface through MD simulations. Wetting and interface chemistry are studied at 8 different temperatures from 700 to 1400 K for four different droplet sizes: with 16, 24, 32 and 40 Å diameters. Chemical reactions are observed at all temperatures and sizes in addition to diffusion between droplet and substrate atoms into each other during the wetting process. To define the level of wetting, we characterized contact angles of aluminum droplets on alumina substrates for all temperatures and sizes by using a method developed by Hautman and Klein. Chemical reactions are more extensive for the small droplets (16 and 24 Å) due to their larger surface to volume ratio in comparison to the larger droplets (32, and 40 Å) of droplets.