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1.
The interfacial intermetallics between Cu and solder were studied for four Sn-Pb compositions at the annealing temperatures
of 125°C, 150°C, and 175°C for up to 30 days. The η-phase (Cu6Sn5) layer formed during reflow continues to grow during annealing. An additional layer of ɛ-phase (Cu3Sn) forms at the η/Cu interface after an incubation annealing time. The thickness results fit a power-law relationship against
time with average exponents 0.69 and 0.44 for the η phase and the ɛ phase, respectively. On prolonged annealing, the proportions
of the individual phases in the total layer reach a steady state. 相似文献
2.
元素铅既对人体存在神经毒性也对环境产生重金属污染,因此,无铅焊料的研究倍受封装业的重视。文章采用温度循环下有限元数值模拟方法,针对4种焊料5种配比包括SnPb(60/40,10/90)、SnPbAg(5/92.5/2.5)、SnAg(96.5/3.5)和SnAgCu(95.5/3.8/0.7),定量评估QFP焊点的塑性应变。给出焊料各参数对于焊点塑性应变的影响程度,第一主元分析显式为△Ps≈-2.56△(Q/R),相应的Y向塑性应变均值降低为优化前的11%。所得的结果可为QFP封装时的焊料选择提供新的设计参考。 相似文献
3.
无铅波峰焊设备的特点 总被引:1,自引:0,他引:1
相对于传统的Sn-Pb焊料,无铅焊料需要较高的焊接温度,而且润湿性差,另外免清洗助焊剂和水溶性助焊剂的固体含量低,活性温度高和活性区间窄。无铅焊料和助焊剂的特性决定了无铅波峰焊设备在结构和材料选用上有很大不同。通过对无铅波峰焊设备的各个部分的特点进行分析,为传统的旧波峰焊设备的改造提供参考。 相似文献
4.
Knowledge of phase equilibria of the Sn-Ag-Cu-Ni quaternary system at the Sn-rich corner is important for the understanding
of the interfacial reactions at the Sn-Ag-Cu/Ni contacts, which are frequently encountered in recent microelectronic products.
Various Sn-Ag-Cu-Ni alloys were prepared and equilibrated at 250°C. The alloys were then quenched and analyzed. The phases
were determined by metallography, compositional analysis, and x-ray diffraction (XRD) analysis. No quaternary phases were
found. The isoplethal sections at 60at.%Sn, 70at.%Sn, 80at.%Sn, and 90at.%Sn at 250°C are determined. The phase equilibrium
relationship was proposed based on the quaternary experimental results and the 250°C isothermal sections of the four constituent
ternary systems, Sn-Ag-Cu, Sn-Ag-Ni, Sn-Cu-Ni, and Cu-Ag-Ni. Because there are no ternary phases in all these three systems,
all the compounds are in fact binary compounds with various solubilities of the other two elements. 相似文献
5.
Phase equilibria of Sn-In based micro-soldering alloys 总被引:1,自引:0,他引:1
I. Ohnuma Y. Cui X. J. Liu Y. Inohana S. Ishihara H. Ohtani R. Kainuma K. Ishida 《Journal of Electronic Materials》2000,29(10):1113-1121
The phase equilibria of Sn-In-X (X=Ag, Bi, Sb, Zn), the most basic information necessary for the development of Pb-free micro-soldering
alloys, were studied using the CALPHAD method. Thermodynamic analyses for describing the Gibbs energies of the constituent phases were made by optimizing the obtained
data on the experimental phase diagrams, and such data in the literature, including data on thermochemical properties. The
present results combined with the thermodynamic database which was recently developed by our group [I. Ohnuma et al., J. Electron. Mater. 28, 1164 (1999)] provide various information on phase equilibria such as liquidus and solidus surfaces, isothermal and vertical
section diagrams, mole fractions of the phase constitutions, etc., and thermodynamic properties such as activity, heat of
mixing, surface energy, viscosity, etc., in multi-component soldering alloy systems including the elements of Pb, Bi, Sn,
Sb, Cu, Ag, Zn, and In. Typical examples for the phase diagrams and thermodynamic properties of Sn-In-X ternary systems are
shown. The application of the database to the alloy design for Pb-free solders is also presented. 相似文献
6.
Development of nano-composite lead-free electronic solders 总被引:1,自引:0,他引:1
Inert, hybrid inorganic/organic, nano-structured chemicals can be incorporated into low melting metallic materials, such as
lead-free electronic solders, to achieve desired levels of service performance. The nano-structured materials technology of
polyhedral oligomeric silsesquioxanes (POSS), with appropriate organic groups, can produce suitable means to promote bonding
between nano-reinforcements and the metallic matrix. The microstructures of lead-free solder reinforced with surface-active
POSS tri-silanols were evaluated using scanning electron microscopy (SEM). Wettability of POSS-containing lead-free solders
to copper substrate was also examined. Steady-state deformation of solder joints made of eutectic Sn-Ag solder containing
varying weight fractions of POSS of different chemical moieties were evaluated at different temperatures (25°C, 100°C, and
150°C) using a rheometric solids analyzer (RSA-III). Mechanical properties such as shear stress versus simple shear-strain
relationships, peak shear stress as a function of rate of simple shear strain, and testing temperature for such nano-composite
solders are reported. The service reliability of joints made with these newly formulated nano-composite solders was evaluated
using a realistic thermomechanical fatigue (TMF) test profile. Evolution of microstructures and residual mechanical property
after different extents of TMF cycles were evaluated and compared with joints made of standard, unreinforced eutectic Sn-Ag
solder. 相似文献
7.
Solder joints used in electronic applications undergo reflow operations. Such operations can affect the solderability, interface
intermetallic layer formation and the resultant solder joint microstructure. These in turn can affect the overall mechanical
behavior of such joints. In this study the effects of reflow on solderability and mechanical properties were studied. Nanoindentation
testing (NIT) was used to obtain mechanical properties from the non-reflow (as-melted) and multiple reflowed solder materials.
These studies were carried out with eutectic Sn-3.5Ag solders, with or without mechanically added Cu or Ag reinforcements,
using Cu substrates. Microstructural analysis was carried out on solder joints made with the same solders using copper substrate. 相似文献
8.
Hwa-Teng Lee Ming-Hung Chen Huei-Mei Jao Chin-Jui Hsu 《Journal of Electronic Materials》2004,33(9):1048-1054
This study investigates the influence of adding Sb on the microstructure and adhesive strength of the Sn3.5Ag solder. Both
solidus and liquidus temperatures increase as Sb additions increase. Adding 1.5wt.%Sb leads to the narrowest range (6.6°C)
between the solidus and liquidus temperature of the solder. Adding Sb decomposes the as-soldered ringlike microstructure of
Sn3.5Ag and causes solid-solution hardening. The as-soldered hardness increases with increasing Sb addition. For long-term
storage, adding Sb reduces the size of the rodlike Ag3Sn compounds. The hardness also increases with increasing Sb addition. Adding Sb depresses the growth rate of interfacial
intermetallic compounds (IMCs) layers, but the difference between 1% and 2% Sb is not distinct. For mechanical concern, adding
Sb improves both adhesive strength and thermal resistance of Sn3.5Ag, where 1.5% Sb has the best result. However, adding Sb
causes a variation in adhesive strength during thermal storage. The more Sb is added, the higher the variation reveals, and
the shorter the storage time requires. This strength variation helps the solder joints to resist thermal storage. 相似文献
9.
10.
Hongqin Wang Hui Zhao Dusan P. Sekulic Yiyu Qian 《Journal of Electronic Materials》2008,37(10):1640-1647
Reactive wetting of solders on Cu and Cu6Sn5/Cu3Sn/Cu substrates was investigated using both (1) the wetting balance, and (2) the hot-stage real time, in situ visualization of the triple-line movement. To understand the phenomenology of the spreading behavior better, comprehensive
real-time in situ observations were performed. It was found that the wetting time during the wetting balance tests for both the lead solder
(63SnPb) and lead-free solder systems (Sn0.7Cu and Sn3.5Ag) is shorter on Cu substrates than it is on Cu6Sn5/Cu3Sn/Cu substrates. The wetting force was not remarkably different on these two substrates for the same solder system. The hot-stage
tests indicate a more pronounced spreading of 63Sn-Pb on Cu6Sn5/Cu3Sn/Cu substrates, along with a much larger spreading area. Spreading of lead-free solders in terms of the triple-line kinetics
studied by using the hot-stage visualization shows no significant difference in the spreading evolution either over Cu or
over Cu6Sn5/Cu3Sn/Cu substrates. 相似文献