Abstract: A diamond conditioner or dresser is needed to regenerate the asperity structure of the pad and recover its designed ability in chemical mechanical polishing (CMP) process. In this paper a new design of diamond conditioner is made by shaping a sintered matrix of polycrystalline diamond (PCD) to form teethed blades. These blades are arranged and embedded in epoxy resin to make a designed penetration angle, called the blade diamond disk. The dressing characteristics of pad surface textures are studied by comparison with conventional diamond conditioner. It is found that the height variation of the diamond tip of blade diamond disk is significantly smaller than the conventional diamond disk. The dressing rate of blade diamond disk is lower than that of the conventional diamond disk, and hence the pad life is prolonged. As a result, reduction of the cost CMP is expected. In addition the pad surface roughness Ra of about 3.79μm is less than Ra of about 4.15μm obtained after dressing using a conventional diamond disk.
Abstract: This paper discusses some issues in micromechanical property of a newly developed Quad Flat No-lead (QFN) 3D stacked die package using three-point bending test approach. The relevant test methodologies were carried out in order to observe the flexural stress, strain, maximum load and deflection of the package. While performing the test, these QFN packages were positioned on the three points test bench, and the specific applied load was then applied and moved down until the package was clearly bent and broken. The related findings indicated that the maximum load was found to be at 251.52 N and the maximum deflection was obtained at 0.41 mm. The results were important for setting related testing parameters (load, stress and strain) before applying the three point cyclic bending test on the QFN stacked die package as the future work.
Abstract: Zinc oxide (ZnO) and Dysprosium (Dy) doped ZnO nano films have been successfully prepared by radio frequency (RF) magnetron sputter. Then the crystal structure, morphology and optical of the films were investigated. All the samples have a preferred orientation with the (0 0 2) orientation perpendicular to the substrates. The surface morphology of the films changes greatly with the increasing of doping content. Agglomeration appears when the doping content is excess, which may result from the recrystallization of the small crystalline grain. The average transmittance in the visible range all exceeds 80% for the different doping content ﬁlms and the band gap increases from 3.26eV to 3.34eV.
Abstract: Diamond wire saw is the leading technology for use in slicing hard brittle material. This paper provides a brief review of its research progress in the most recent years. According to the bonding material kinds of diamond wire saw, it can be classified into three main categories, i.e. metallic bonding materials, organic bonding materials, and resin bonding materials. In the past decade, several new major technical developments in fixed abrasive diamond wire saw have emerged. This paper investigates the related literature on four different types of fixed abrasive diamond wire saws, presents their manufacturing processes and machining performance, and compares the tension and anti-abrasion of the wire saws, removal efficiency of slicing, and their applications in silicon slicing.
Abstract: Zinc stannate Zn2SnO4 (ZTO) nanoparticles were synthesized via a hydrothermal process utilizing sodium carbonate (Na2CO3) as a weak basic mineralizer. The samples were hydrothermally treated at 150, 200, and 250oC for 48 h. The X-ray diffraction (XRD) patterns show that the highly-crystalline ZTO nanostructure could be formed in a well-dispersed manner for the 250°C sample at a particle size of less than 50 nm. As determined from transmission electron microscopy (TEM) results, ZTO nanoparticles are face-centered cubic single crystals agglomerated together. The Raman spectra results showed that the ZTO nanocrystals have a spinel structure. Furthermore, photocatalytic activity was tested with methylene blue (MB) by UV irradiation. The ZTO synthesized by the 2 M Na2CO3 mineralizer at 250oC demonstrated excellent photocatalytic activity. The ZTO treated three different ways had three distinct UV-Visible absorption curves, which directly influences their corresponding photocatalytic activity.
Abstract: Underfilling is the preferred process to reduce the impact of the thermal stress that results from the mismatch in the coefficient of thermal expansion (CTE) between the silicon chip and the substrate in Flip Chip Packaging. Voids formation in underfill is considered as failure in flip chip manufacturing process. Voids formation possibly caused by several factors such as poor soldering and flux residue during die attach process, voids entrapment due moisture contamination, dispense pattern process and setting up the curing process. This paper presents the optimization of two steps curing profile in order to reduce voids formation in underfill for Hi-CTE Flip Chip Ceramic Ball Grid Array Package (FC-CBGA). A C-Mode Scanning Aqoustic Microscopy (C-SAM) was used to scan the total count of voids after curing process. Statistic analysis was conducted to analyze the suitable curing profile in order to minimize or eliminate the voids formation. It was shown that the two steps curing profile provided solution for void elimination.
Abstract: The ZnO films were deposited on Si substrate by radio frequency (RF) magnetron sputtering. The effects of the Ar/O2 ratios on the structural characteristics and the internal stress in the ZnO films have been studied. The SEM images shows that the ZnO grains are nano-sized and tightly packed. The ZnO films are highly c-axis oriented with the (002) plane parallel to the substrate. The samples has a stress of the order of 1.0 × 1010 dyn/cm2. It is found that the size of ZnO crystal grains distinctly depends on the stress in the ZnO films. In order to deposite ZnO films with good crystalline quality, the stress caused by the growth process can be depressed by adjusting the Ar/O2 ratios.
Abstract: Silicon was electrodeposited by electrochemical reduction of silicon tetrachloride in propylene carbonate solvent on an alloy of nickel-titanium-niobium and nickel, which were used as working electrodes respectively. The effect of two substrates as working electrodes on the electrodeposition ability of the silicon was investigated by scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS). Results show that using an alloy of titanium, nickel and niobium as working electrode is better than nickel in the morphology and deposition yield of silicon.