The electrochemical migration（ECM） behavior and mechanism of immersion silver processing circuit board（PCB-ImAg）and hot air solder leveling circuit board（PCB-HASL） under the 0.1 mol/L Na2SO4 absorbed thin liquid...The electrochemical migration（ECM） behavior and mechanism of immersion silver processing circuit board（PCB-ImAg）and hot air solder leveling circuit board（PCB-HASL） under the 0.1 mol/L Na2SO4 absorbed thin liquid films with different thicknesses were investigated using stereo microscopy and scanning electron microscopy（SEM）.Meanwhile,the corrosion tendency and kinetics rule of metal plates after bias application were analyzed with the aid of electrochemical impedance spectroscopy（EIS）and scanning Kelvin probe（SKP）.Results showed that under different humidity conditions,the amount of migrating corrosion products of silver for PCB-ImAg was limited,while on PCB-HASL both copper dendrites and precipitates such as sulfate and metal oxides of copper/tin were found under a high humidity condition（exceeding 85%）.SKP results indicated that the cathode plate of two kinds of PCB materials had a higher corrosion tendency after bias application.An ECM model involving multi-metal reactions was proposed and the differences of ECM behaviors for two kinds of PCB materials were compared.展开更多
Effects of Cu underlayer on the structure of Fe50Mn50 films were studied. Samples with a structure of Fe50Mn50（200 nm）/ Cu(tCu) were prepared by magnetron sputtering on thermally oxidized silicon substrates at room ...Effects of Cu underlayer on the structure of Fe50Mn50 films were studied. Samples with a structure of Fe50Mn50（200 nm）/ Cu(tCu) were prepared by magnetron sputtering on thermally oxidized silicon substrates at room temperature. The thickness of Cu underlayer varied from 0 to 60 nm in the intervals of 10 nm. High-vacuum annealing treatments, at different temperatures of 200, 300 and 400 ℃ for 1 h, respectively, on the Fe50Mn50（200 nm）/ Cu（20 nm） thin films were performed. The surface morphologies and textures of the samples were measured by field emission scan electronic microscope （FE-SEM） and X-ray diffraction（XRD）. Energy dispersive X-ray spectroscopy （EDX） and Auger electron spectroscopy（AES） were used to analyze the compositional distribution. It is found that Cu underlayer has an obvious induce effect on （111） orientation of Fe50Mn50 thin films. The induce effects of Cu on （111） orientation of Fe50Mn50 changed with the increase of Cu layer thickness and the best effect was obtained at the Cu layer thickness of 20 nm. High-vacuum annealing treatments cause the migration of Mn atoms towards surface of the film and interface between Cu layer and substrate. With the increasing annealing temperature, migration of Mn atoms is more obvious, which leads to a Fe-riched Fe-Mn alloy film.展开更多
基金Project(51271032)supported by the National Natural Science Foundation of China
文摘The electrochemical migration（ECM） behavior and mechanism of immersion silver processing circuit board（PCB-ImAg）and hot air solder leveling circuit board（PCB-HASL） under the 0.1 mol/L Na2SO4 absorbed thin liquid films with different thicknesses were investigated using stereo microscopy and scanning electron microscopy（SEM）.Meanwhile,the corrosion tendency and kinetics rule of metal plates after bias application were analyzed with the aid of electrochemical impedance spectroscopy（EIS）and scanning Kelvin probe（SKP）.Results showed that under different humidity conditions,the amount of migrating corrosion products of silver for PCB-ImAg was limited,while on PCB-HASL both copper dendrites and precipitates such as sulfate and metal oxides of copper/tin were found under a high humidity condition（exceeding 85%）.SKP results indicated that the cathode plate of two kinds of PCB materials had a higher corrosion tendency after bias application.An ECM model involving multi-metal reactions was proposed and the differences of ECM behaviors for two kinds of PCB materials were compared.
基金Project(19974005) supported by the National Natural Science Foundation of China
文摘Effects of Cu underlayer on the structure of Fe50Mn50 films were studied. Samples with a structure of Fe50Mn50（200 nm）/ Cu(tCu) were prepared by magnetron sputtering on thermally oxidized silicon substrates at room temperature. The thickness of Cu underlayer varied from 0 to 60 nm in the intervals of 10 nm. High-vacuum annealing treatments, at different temperatures of 200, 300 and 400 ℃ for 1 h, respectively, on the Fe50Mn50（200 nm）/ Cu（20 nm） thin films were performed. The surface morphologies and textures of the samples were measured by field emission scan electronic microscope （FE-SEM） and X-ray diffraction（XRD）. Energy dispersive X-ray spectroscopy （EDX） and Auger electron spectroscopy（AES） were used to analyze the compositional distribution. It is found that Cu underlayer has an obvious induce effect on （111） orientation of Fe50Mn50 thin films. The induce effects of Cu on （111） orientation of Fe50Mn50 changed with the increase of Cu layer thickness and the best effect was obtained at the Cu layer thickness of 20 nm. High-vacuum annealing treatments cause the migration of Mn atoms towards surface of the film and interface between Cu layer and substrate. With the increasing annealing temperature, migration of Mn atoms is more obvious, which leads to a Fe-riched Fe-Mn alloy film.
