Showing papers by "Ming Li published in 2005"
TL;DR: In this article, nano-sized amorphous CaSiO3 and β-wollastonite (β-CS) powders were produced by chemical precipitation method and subsequent heat treatment, using Ca(NO3)2·4H2O and Na2SiO 3·9H 2O as the starting materials, polyethylene glycol as the dispersant.
56 citations
TL;DR: In this article, the diffusion barrier performances of Mo, Mo-N and Mo/Mo-N metallization layers deposited by sputtering Mo in Ar/N2 atmospheres were studied.
52 citations
30 Aug 2005
TL;DR: In this article, the effects of alloying elements, such as lanthanum, titanium, aluminum, and chromium, on the oxidation resistance, the wetting properties and the tensile properties of Sn-Zn based lead-free solder were studied.
Abstract: In this work, the effects of alloying elements, such as lanthanum, titanium, aluminum, and chromium, on the oxidation resistance, the wetting properties and the tensile properties of Sn-Zn based lead-free solder were studied. The results show that, under the condition of experiment, alloying additions of Al and Cr can significantly improve the oxidation resistance of Sn-9Zn solder, and Ti have a less effect. Further experiments show that the addition of Al worsens the wetting properties of Sn-9Zn solder, but Cr does not have unfavorable effect on the wetting properties and the melting point of Sn-9Zn solder. The effect of Cr alloying content on the oxidation resistance of Sn-9Zn solder was further studied, and the results indicate that increasing Cr content can enhance the oxidation resistance. To some extent the addition of Cr can improve the elongation of Sn-9Zn solder, but has a less effect on the tensile strength of that.
10 citations
30 Aug 2005
TL;DR: The most important factor that causes delamination between copper alloy lead frame and epoxy mold compound is copper oxide as mentioned in this paper, and the most important factors that influence the formation of oxide film on copper substrate, oxidation mechanism of several leadframe copper alloys was investigated.
Abstract: The most important factor that causes delamination between copper alloy lead frame and epoxy mold compound is copper oxide. To identify the factors that influence the formation of oxide film on copper substrate, oxidation mechanism of several lead-frame copper alloys was investigated. The oxide film structure of copper alloy was found to be CuO/Cu/sub 2/O/Cu by AES analysis. Various copper alloys had great difference in CuO/Cu/sub 2/O ratio. Oxidation rate of copper alloy was further studied by measuring the oxide thickness as a function of time at 320/spl deg/C. The results showed that C5191 and C7025 had lower oxidation rate than EFTEC64T and C194, which promoted the growth of CuO. The calculation from AES depth profile of copper atom confirmed that grain boundary diffusion coefficients of C5191 and C7025 were nearly two magnitudes smaller than those of EFTEC64T and C194. At a low temperature (usually below half of melting point), the growth of oxide film is mainly dominated by the grain boundary diffusion. It was found by SPM analysis that copper alloys with smaller grain size had more paths for copper atom to diffuse from substrate to the interface of oxide and air, thus leading to higher oxidation rate. The segregation effect of solute elements of copper alloys at the oxide/substrate interface also played an important role in the growth of oxide.
5 citations