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排序方式: 共有1354条查询结果,搜索用时 15 毫秒
101.
Marian Zeman 《Welding International》2013,27(2):83-90
This study evaluated both the joint strength of copper wire on a copper substrate with tin plating and the joint reliability of copper wire bonding after heat treatment. The suitable tin thickness and bonding conditions, which are stage temperature, wire bonding power and bonding time, were chosen by the peel test after copper wire bonding. Tin thickness of 10 m showed a high bonding rate under the conditions of stage temperature 373 K, bonding power 500–700 mW and bonding time 30 50 ms. Before heat treatment, the peel strength of the copper wire on the copper substrate with tin plating conditions was weaker than that of gold wire on a gold substrate. After heat treatment for more than 70 h at 298 K, the peel strength of the copper wire became higher than that of the gold wire and twice as high as the initial bonding strength. The tin layer remained between the copper wire and copper substrate before heat treatment. When the samples were held at 298 K, tin reacted with copper and turned into a Cu–Sn intermetallic compound. Upon completion of this reaction at 298 K for over 70 h, the soft tin layer between the copper wire and copper substrate disappeared. Therefore, the peel strength of copper wire after heat treatment increased. These results were observed by scanning electron microscope images of the interface between the copper wire and copper substrate before and after heat treatment. 相似文献
102.
Hitoshi Tanaka Morimasa Tanimoto Akira Matsuda Takeo Uno Masaaki Kurihara Shoji Shiga 《Journal of Electronic Materials》1999,28(11):1216-1223
Pb-free solderable surface finishing is essential to implement Pb-free solder assembly in order to meet with the growing demand
of environmental consciousness to eliminate Pb from electronic products. Two types of widely applicable Pb-free surface finishing
technologies are developed. One is the multilayer-system including Pd with Ni undercoat. Heat-resistance of Pd enables whole-surface-plating
on to leadframe before IC-assembling process. The other is the double-layer-system with low-melting-point-materials, for example,
thicker Sn underlayer and thinner Sn-Bi alloy overlayer, dilutes Sn-Bi alloy’s defects of harmful reactivity along with substrate
metal and mechanical brittleness with keeping its advantages of solder-wettability and no whisker. 相似文献
103.
Rajen S. Sidhu Shantanu V. Madge Xin Deng Nikhilesh Chawla 《Journal of Electronic Materials》2007,36(12):1615-1620
We report on the nature of the orientation of Ag3Sn and the Ag3Sn/Sn interface in Sn-3.5Ag solder. Orientation imaging microscopy (OIM) and transmission electron microscopy (TEM) were used
to characterize the orientation and nature of the interface, respectively. OIM and TEM showed that Sn-3.5Ag containing spherical
Ag3Sn particles does not have a preferred orientation with respect to the Sn matrix. However, needle-like Ag3Sn formed during slower cooling appeared to have a preferred orientation within individual Sn colonies. The interface between
Sn and Ag3Sn appeared to be incoherent, as confirmed by high-resolution TEM analysis. 相似文献
104.
The electromigration-induced failure of Sn95/Sb5 flip chip solder bumps was investigated. The failure of the joints was found
at the cathode/chip side after current stressing with a density of 1×104 A/cm2 at 150°C for 13 sec. The growth of intermetallic compounds (IMCs) was observed at the anode side after current stressing.
Voids were found near the current crowding area in the cathode/chip side, and the (Cu,Ni)6Sn5 IMC at the cathode/chip end was transformed into the Sn phase. The failure mechanism for Sn95/Sb5 flip chip solder joint
is proposed in this paper. 相似文献
105.
A new and novel electrically conducting ‘polymeric-inorganic’ composite cation-exchange material; polyaniline Sn(IV) tungstoarsenate was prepared by incorporating polyaniline into inorganic ion-exchanger material. It possessed improved ion-exchange capacity, high chemical and thermal stabilities, reproducibility and selectivity for some specific metal ions. Kinetic study of exchange for some divalent metal ions of alkaline earths and transition metals was carried out under the conditions favoring a particle diffusion-controlled ion-exchange phenomenon and some physical parameters such as self diffusion coefficient D0, energy of activation Ea and entropy of activation ΔS* were determined. The temperature dependence of electrical conductivity of this composite material with increasing temperatures was measured by using 4-in-line-probe DC electrical conductivity measuring-technique. The conductivity values lie in the semiconductor region, i.e. in the range of 10−3 S cm−1 that follow the Arrhenius equation. The energy of activation of electrical conduction for the composite was also calculated. 相似文献
106.
Jong-Hwan Park Jong-Hyun Lee Yong-Ho Lee Yong-Seog Kim 《Journal of Electronic Materials》2002,31(11):1175-1180
The reaction characteristics of molten Au/Sn eutectic solder with potential diffusion-barrier materials of optoelectronic
packages were investigated. The characteristics were studied by reflowing the solder on Pt, Ni, and Co plates, respectively,
and by measuring the thickness of the reaction product. In addition, the dissolution rate of Pt into the solder was measured.
The results indicated that Pt, which is commonly used as the diffusion-barrier layer in the under-bump metallurgy (UBM) of
optoelectronic packages, reacts readily with the molten solder, resulting in discontinuous reaction products at the solder/Pt
interface. Cobalt, on the other hand, reacted with the solder at an order of magnitude slower rate than that of Pt and provided
an effective barrier against the reaction with the solder. 相似文献
107.
D. Pan I. Dutta S. G. Jadhav G. F. Raiser S. Ma 《Journal of Electronic Materials》2005,34(7):1040-1046
The creep behavior of Pb-10wt.%Sn, a common high-lead solder used in microelectronic packaging, was studied by impression
creep testing of ball-gridarray (BGA) solder balls attached to an organic substrate, both above and below the solvus temperature
(408 K). Below the solvus temperature, the solder microstructure consists of roughly equiaxed grains of the Pb-rich solid
solution α, which contains <5wt.%Sn in solution, with a coarse dispersion of Sn-rich β precipitates. Here, the creep behavior
of the solder is controlled by dislocation climb via dislocation core diffusion, yielding n≈4 and Q≈60 kJ/mole. Above the
solvus temperature, where the entire 10wt.%Sn is in solution, the creep mechanism becomes controlled by viscous glide of dislocations,
limited by solute drag, with n≈3 and Q≈92 kJ/mole. Based on experimental data, creep equations for the as-reflowed solder
in the two temperature regimes are given. Comparison of the present data with those available in the literature showed good
agreement with the proposed laws. 相似文献
108.
Minna Arra Dongkai Shangguan Erro Ristolainen Toivo Lepistö 《Journal of Electronic Materials》2002,31(11):1130-1138
Solder balling in Sn/Ag/Cu solder pastes was studied in this work. Three different solder pastes, several different reflow
profiles and conditions, and two stencil thicknesses were used in the investigation. During the first phase, called the verification
phase, the solder pastes were checked to ensure they met the minimum requirements. In the process-screening phase, the reflow
profile was varied. Results show that besides flux chemistry, reflow atmosphere plays the major role in solder balling. The
average number of solder balls with the best paste was one fifth of that with the worst paste. Furthermore, with all the pastes,
the number of solder balls dropped close to zero when nitrogen atmosphere was used. Another finding during the reflow process
screening was the influence of the stencil thickness on the solder-balling result. With a thinner stencil, two of the pastes
exhibited significant solder balling. This is assumed to be caused by the different ability of fluxes to withstand oxidation
during the preheating in the reflow process. In the last phase, the effect of the solder-paste particle size on solder balling
was studied more closely. The flux chemistry was kept unchanged, and the solder particle size was varied between type 3 and
type 4. The results show that, with type 4 paste, significantly more solder balls are formed compared to type 3 paste. It
was also confirmed that, regarding the reflow profile, the ramp-up rate from 150°C to 217°C and the reflow atmosphere were
the most significant factors that determine the solder-ball formation for both types of paste. 相似文献
109.
Cu-15Ni-8Sn-0.4Si合金铸态组织结构及成分偏析研究 总被引:6,自引:1,他引:6
用金相、扫描电镜及电子能谱微区成分分析等方法对添加少量Si的Cu-15Ni-8Sn合金的铸态组织结构及成分偏析进行了研究。结果发现:Cu-15Ni-8Sn-0.4Si合金的铸态组织分为三层,除具有明显的枝晶外,还有块状的(Cu、Ni)3Sn相和溶有少量Cu的Ni2Si和Ni3Sn相组成的第二层,在两层之间为组织形态复杂的过渡区。宏观上铸态组织存在Sn的反偏析,Sn的含量从外到内呈现下降趋势。与非真空熔铸相比真空熔铸能明显改善Cu-15Ni-8Sn-0.4Si合金反偏析现象。均匀化退火对改善Sn的反偏析作用不大;枝晶组织可基本消除,但Ni、Si元素形成的化合物仍难以完全溶解。添加少量Si的Cu-15Ni-8Sn合金由于Ni2Si和Ni3Si相的形成,通过阻碍晶粒长大和时效沉淀而强化合金。 相似文献
110.
采用碳热还原法以及沥青裂解包覆技术,制备具有核壳结构的Sn/C复合负极材料,对采用改性天然石墨与人造石墨作为内核的效果作了比较,并分析研究壳层的厚度对材料综合性能的影响.结果表明,采用改性天然石墨作为内核能更有效分散Sn金属颗粒,另外沥青裂解碳包覆层的厚度对材料的循环稳定性具有较大的影响.以改性天然石墨为内核,具有(10%+20%)双层包覆结构的负极样品具有最佳的综合性能,首次库伦效率为76.3%,54周的容量保持率为99%.材料结构的设计以及结构的合成工艺是解决锡基合金负极材料体积效应的重要途径. 相似文献