The surface characteristics of under bump metallurgy (UBM) in electroless nickel immersion gold (ENIG) deposition

This paper discusses on the surface characteristics of each of the seven set-up process steps prior completion of under bump metallurgy (UBM) deposition. The Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) techniques were used to obtain the surface roughness and morphology of each deposition process. The elemental analysis using Energy Disperse X-Ray (EDX) and precision micro-cross-section using Focus Ion Beam (FIB) was also used in this study. The first zincation process has high surface roughness but preserved surface morphology of initial thin-film surface. The second zincation provides the improved surface roughness due to the replacement aluminum layer with ion zinc in the solution. Smooth surfaces leads to better shear strength. However, second zincation will affect the Al thickness, hence excessive attacks on Al layer may cause reliability problem.     

Enrichment of carotene from palm oil by organic solvent nanofiltration

Palm oil is one of the richest sources of natural plant carotene with typical concentration of about 0.5–0.7 g/L. Unfortunately, during physical refining of palm oil, most of the carotenes were destroyed by high temperatures and this represents a loss of potential source of natural carotene. Various techniques have been developed to extract and recover carotenes from palm oil, however these processes often require high energy usage, and usually renders the oil useless for further consumption. Recently, organic solvent nanofiltration (OSN) has become an important method for molecular separation particularly for the separation of low molecular weight bioactive compounds. This work presents the application of OSN membranes for the separation of carotene from a crude palm oil/solvent system. Several commercial OSN membranes (DuraMem and PuraMem series) fabricated from polyimide were evaluated for their separation abilities. PuraMem 280 showed the best selectivity performance, with the concentration of carotene in permeate oil increased from 0.60 to 0.79 g/L when hexane was used as the solvent. Runs by using DuraMem 150, DuraMem 300 and DuraMem 500 showed low or no selectivity between carotene and triglyceride in all solvents. It was found that the rejection of carotene depends strongly on the type of solvents. A coupled solution diffusion and film theory was also utilized to model carotene transport through OSN membrane. It was demonstrated that OSN can serve as an alternative for the direct carotene recovery from palm oil and can be potentially applied for other minor compounds recovery from vegetable oils.     

Effect of Ag Content and the Minor Alloying Element Fe on the Mechanical Properties and Microstructural Stability of Sn-Ag-Cu Solder Alloy Under High-Temperature Annealing

This study compares the high-Ag-content Sn-3Ag-0.5Cu with the low- Ag-content Sn-1Ag-0.5Cu solder alloy and the three quaternary solder alloys Sn-1Ag-0.5Cu-0.1Fe, Sn-1Ag-0.5Cu-0.3Fe, and Sn-1Ag-0.5Cu-0.5Fe to understand the beneficial effects of Fe on the microstructural stability, mechanical properties, and thermal behavior of the low-Ag-content Sn-1Ag-0.5Cu solder alloy. The results indicate that the Sn-3Ag-0.5Cu solder alloy possesses small primary β-Sn dendrites and wide interdendritic regions consisting of a large number of fine Ag₃Sn intermetallic compound (IMC) particles. However, the Sn-1Ag-0.5Cu solder alloy possesses large primary β-Sn dendrites and narrow interdendritic regions of sparsely distributed Ag₃Sn IMC particles. The Fe-bearing SAC105 solder alloys possess large primary β-Sn dendrites and narrow interdendritic regions of sparsely distributed Ag₃Sn IMC particles containing a small amount of Fe. Moreover, the addition of Fe leads to the formation of large circular FeSn₂ IMC particles located in the interdendritic regions. On the one hand, tensile tests indicate that the elastic modulus, yield strength, and ultimate tensile strength (UTS) increase with increasing Ag content. On the other hand, increasing the Ag content reduces the total elongation. The addition of Fe decreases the elastic modulus, yield strength, and UTS, while the total elongation is still maintained at the Sn-1Ag-0.5Cu level. The effect of aging on the mechanical behavior was studied. After 720 h and 24 h of aging at 100°C and 180°C, respectively, the Sn-1Ag-0.5Cu solder alloy experienced a large degradation in its mechanical properties after both of the aging conditions, whereas the mechanical properties of the Sn-3Ag-0.5Cu solder alloy degraded more dramatically after 24 h of aging at 180°C. However, the Fe-bearing SAC105 solder alloys exhibited only slight changes in their mechanical properties after both aging procedures. The inclusion of Fe in the Ag₃Sn IMC particles suppresses their IMC coarsening, which stabilizes the mechanical properties of the Fe-bearing SAC105 solder alloys after aging. The results from differential scanning calorimetry (DSC) tests indicate that the addition of Fe has a negligible effect on the melting behavior. However, the addition of Fe significantly reduces the solidification onset temperature and consequently increases the degree of undercooling. In addition, fracture surface analysis indicates that the addition of Fe to the Sn-1Ag-0.5Cu alloy does not affect the mode of fracture, and all tested alloys exhibited large ductile dimples on the fracture surface.     

Design of Wideband Rectangular-Shaped Coupler with Virtual Short Stubs for Wireless Communication Applications

This article presents the design of the sectional rectangular-shaped directional couplers with tight coupling of 3-dB over frequency of 2–6 GHz. The designed coupler consists of two substrates and one common ground plane between the substrate layers. It also formed by two conducting strips with virtual short stubs are placed to the middle section at the top and bottom layer, which coupled through three-section rectangular slots at the ground plane. The effect of these additional stubs in the design is studied and observed. The design and analysis are performed with the use of full-wave electromagnetic simulation software package, CST Microwave Studio. This designed coupler has been fabricated and its wideband performance is verified.     

3,4-Dichlorophenoxyacetate interleaved into anionic clay for controlled release formulation of a new environmentally friendly agrochemical

A new layered organic–inorganic nanohybrid material, zinc-aluminum-3,4-dicholorophenoxyacetate (N3,4-D) in which an agrochemical, 3,4-dichlorophenoxyacetic acid (3,4-D), is intercalated into zinc-aluminum-layered double hydroxide (ZAL), was synthesized by coprecipitation method. A well-ordered nanomaterial was formed with a percentage loading of 53.5% (w/w). Due to the inclusion of 3,4-D, basal spacing expanded from 8.9 Å in ZAL to 18.7 Å in N3,4-D. The Fourier transform infrared study shows that the absorption bands of the resulting nanohybrid composed of both the 3,4-D and ZAL further confirmed the intercalation episode. Thermal analysis shows that ZAL host enhances the thermal stability of 3,4-D. Controlled-release experiment shows that the release of 3,4-D in the aqueous media is in the order of phosphate > carbonate > sulfate > chloride. These studies demonstrate the successful intercalation of the 3,4-D and its controlled release property in various aqueous media.     

Senior managers’ perception on green information systems (IS) adoption and environmental performance: Results from a field survey

Based on a Belief-Action-Outcome framework, we produced a model that shows senior managers’ perception of both the antecedents to and the consequences of Green IS adoption by a firm. This conceptual model and its associated hypotheses were empirically tested using a dataset generated from a survey of 405 organizations. The results suggest that coercive pressure influences the attitude toward Green IS adoption while mimetic pressure does not. In addition, we found that there was a significant relationship between Green IS adoption, attitude, and consideration of future consequences. Finally, we found that only long term Green IS adoption was positively related to environmental performance.     

Molecular Weight Determination of Palm Olein Polyols by Gel Permeation Chromatography Using Polyether Polyols Calibration

Natural oil polyols have been intensively developed and successfully used for the production of various polymers, notably polyurethanes. The need to access the average molecular weight (MW) and the MW distribution (MWD) has led to the efforts to have a precise and reliable determination method. A series of commercial polyether polyols, with well‐defined MW, was used as a gel permeation chromatography (GPC) calibration standard to determine the MW of palm olein polyols. This GPC analysis was compared to the one calibrated against the commercially available polystyrene (PS) standards and to the number‐average molecular weight (M_n) obtained via vapor pressure osmometry (VPO) technique. For example, the M_n obtained for palm olein polyol E‐135 calibrated against polyether polyols was 2,537 Da, which was closer to the M_n via VPO (1,618 Da), than the M_n obtained using PS as calibration standards (3,836 Da). Hence, this GPC analysis using polyether polyols as calibration standards can offer reassured determination of MWD of palm olein polyols.     

Synthesis of gallium nitride nanostructures by nitridation of electrochemically deposited gallium oxide on silicon substrate

Gallium nitride (GaN) nanostructures were successfully synthesized by the nitridation of the electrochemically deposited gallium oxide (Ga₂O₃) through the utilization of a so-called ammoniating process. Ga₂O₃ nanostructures were firstly deposited on Si substrate by a simple two-terminal electrochemical technique at a constant current density of 0.15 A/cm² using a mixture of Ga₂O₃, HCl, NH₄OH and H₂O for 2 h. Then, the deposited Ga₂O₃ sample was ammoniated in a horizontal quartz tube single zone furnace at various ammoniating times and temperatures. The complete nitridation of Ga₂O₃ nanostructures at temperatures of 850°C and below was not observed even the ammoniating time was kept up to 45 min. After the ammoniating process at temperature of 900°C for 15 min, several prominent diffraction peaks correspond to hexagonal GaN (h-GaN) planes were detected, while no diffraction peak of Ga₂O₃ structure was detected, suggesting a complete transformation of Ga₂O₃ to GaN. Thus, temperature seems to be a key parameter in a nitridation process where the deoxidization rate of Ga₂O₃ to generate gaseous Ga₂O increase with temperature. The growth mechanism for the transformation of Ga₂O₃ to GaN was proposed and discussed. It was found that a complete transformation can not be realized without a complete deoxidization of Ga₂O₃. A significant change of morphological structures takes place after a complete transformation of Ga₂O₃ to GaN where the original nanorod structures of Ga₂O₃ diminish, and a new nanowire-like GaN structures appear. These results show that the presented method seems to be promising in producing high-quality h-GaN nanostructures on Si.