Electromigration tests of SnAg solder bump samples with 15 µm bump height and Cu under-bump-metallization (UBM) were performed. The test conditions were 1.45ˆ10 4 A/cm 2 at 185˝C and 1.20ˆ10 4 A/cm 2 at 0˝C. A porous Cu 3 Sn intermetallic compound (IMC) structure was observed to form within the bumps after several hundred hours of current stressing. In direct comparison, annealing alone at 185˝C will take more than 1000 h for porous Cu 3 Sn to form, and it will not form at 170˝C even after 2000 h. Here we propose a mechanism to explain the formation of this porous structure assisted by electromigration. The results show that the SnAg bump with low bump height will become porous-type Cu 3 Sn when stressing with high current density and high temperature. Polarity effects on porous Cu 3 Sn formation is discussed.
The precursor of LaMnO3 obtained by the reaction of metal salt with potassium
hydroxide was subjected to hydrothermal condition in an autoclave then the precipitate was treated in different temperatures (600-900°C). The effect of precursor type and hydrothermal crystallization conditions on the morphology of lanthanide manganese grains was investigated. The morphology and the structure of the products was studied by transmission electron microscope (TEM) and X-ray diffraction (XRD). Different shapes of LaMnO3 can be obtained by controlling prepare condition and treated temperature. The XRD results showed the formation of perovskite-type LaMnO3.
Fe3O4 nanoparticles were simply prepared by a wet chemical solution method. In this method, poly (N-vinyl-2-pyrrolidone) (PVP) was used as surface modified reagent to control the shape of the product. Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) were used to characterize the asprepared Fe3O4 nanoparticles. Furthermore, the magnetic properties of the sample were investigated by a VSM (vibrating sample magnetometer) technique.
The present practice of managing reticle haze defectivity involves reticle inspection at regular intervals, coupled with inspection of print-down wafers in between reticle inspections. The sensitivity of the reticle inspection tool allows it to detect haze defects before they are large enough to print on the wafer. Cleaning the reticle as soon as the reticle inspector detects haze defects could result in a shorter reticle lifetime. Thus there is strong motivation to develop a methodology to determine what size defect on the reticle results in a printable defect on the wafer. Printability depends upon several variables in the litho process as well as whether the defect resides in a high-MEEF (Mask Error Enhancement Factor) or low-MEEF area of the die. 1 Trying to use wafer inspection to identify the first appearance of haze defects may require inspector recipe settings that are not suited to a practical wafer scan.A novel method of managing such defects is to map the coordinates of the defects from the reticle onto the wafer, and apply a separate, hyper-sensitive threshold to a small area surrounding the given coordinates. With this method, one can start to correlate the size of the defects printed on the wafer to the light transmission rate from the corresponding site on the reticle scan, and thus can predict the starting point at which the haze defects on the reticle are likely to print on the wafer. The experiment described in this paper is a first step in exploring the feasibility of this method to help track the growth of nascent haze defects and optimize the timing to rework the reticles. The methodology may have extendibility to other applications in which hyper-sensitive wafer inspection at localized areas within the die would be beneficial, such as monitoring weak spots found by Optical Rule Check, Process Window Qualification, electrical test or failure analysis.
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