International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Eutectic (63% tin-37% lead) or near-eutectic (40% tin-60% lead) tin-lead solder is widely used for creating electrical interconnections between the printed wiring board (PWB) and the components mounted on the board surface. For components mounted directly on the PWB mounting pads, that is, surface mounted components, the tin-lead solder also constitutes the mechanical interconnection. Eutectic solder has a melting point of 183°C (361°F). It is important to realize that its homologous temperature, defined as the temperature in degrees Kelvin over its melting point temperature (T(m)), also in degrees Kelvin, is defined as T/T(m). At room temperature (25°C = 298K), eutectic solder's homologous temperature is 0.65. It is widely acknowledged that materials having a homologous temperature ≥ 0.5 are readily subject to creep, and the solder joints of printed wiring assemblies are routinely exposed to temperatures above room temperature. Hence, solder joints tend to be subject to both thermal fatigue and creep. This can lead to premature failures during service conditions. The geometry, that is, the lead configuration, of the joints can also affect failure. Various geometries are better suited to withstand failure than others. The purpose of this paper is to explore solder joint failures of dual in-line (DIP) integrated circuit components, leadless ceramic chip carriers (LCCCs), and gull wing and J-lead surface mount components mounted on PWBs.

Thesis (M.S.)--State University of New York at Binghamton, Department of Mechanical Engineering, 2005. / Includes bibliographical references (leaves 70-72).

Lead-free solders such as SnAg and SnAgCu are used extensively as replacements of SnPb solders in microelectronics packaging. But these alloys have several drawbacks, such as poor wetting ability and formation of intermetallic compounds (IMC). Doping of rare earth element (RE) on SnAg alloys has been found to improve the wetting property, reduce IMCs and their growth, and refine the microstructure which results in improved mechanical properties of the solder. This study focuses on establishing the quantitative effects of RE doping on the microstructure and mechanical behavior of 96.5Sn3.5Ag alloy. SnAg alloys with different amounts of Lanthanum were made. Specimens were cast under typical reflow conditions, and then aged at different temperatures for three different aging times. Quantitative microscopy was conducted on samples with different amounts of La doping. It was found that doping greatly reduces the grain size, as well as the size of the intermetallic particles Ag3Sn. However, the inter-particle spacing remains relatively unaffected by the La doping amount. Creep tests at various temperatures and strain rates were conducted. The results show that La doping increases creep resistance of the SnAg alloy by ~15%. The creep test result can be fit into a modified microstructure dependent Anand model. A new constitutive law was also proposed to account for the hierarchal microstructure over multiple length scales. Specifically, at the sub micrometer scale, the SnAg eutectic region is treated as a particulate-reinforced composite with the Ag3Sn being the particle and Sn being the matrix. At the micrometer length scale, the solder alloys is treated as a two-phase composite with the Sn dendrite as the particle and the SnAg eutectic region as the matrix. Good agreement was found between the model predictions and the creep test results. Fatigue test was performed on bulk samples. It was found that RE doping increases the fatigue life of SnAg alloy by a factor of 5.

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2008. / Includes bibliographical references.

The aim of this masterś thesis is to investigate properties of lead-free low-temperature solders after termal aging. The theoretical part is focused on various types of lead - free solders, pastes used for the manufacture of electrical circuits by thick-film technology and methods of testing the properties of the soldered joints. The practical part deals with the design and production of test substrates for testing the solder joints formed between the SMD component and the ceramic substrate. Two solder bismuth-containing solder was selected for testing, the SAC solder was selected as the reference. After aging with temperature cycling from -30 ° C to 115 ° C, the data obtained by testing the mechanical strength of the solder joint by the shear test is evaluated.

This work deals research of the reliability of leed-free solder joints. It summarizes the basic knowledge of lead-free solder alloys, soldering and testing process, the soldered joints. The work is done selecting the most important factors entering into the soldering process. The method of the DOE sought the optimal combination of factors, which would correspond to the highest quality solder joints.

This work deals with flushing monitoring of spreading velocity on solder finishes Niau, OSP, Sn deposited on copper plated base material FR4 using digital cameras. After the reflow process is measured by length of spreading solder and size of wetting angle. It evaluates and compares the time dependence of velocity of spreading solder, length of solder spreading and wetting angle for NiAu, OSP, Sn finishes at different temperatures reflow and surface treatment.

This thesis deals with the design and implementation of a device for measuring pull strength by surface mounted devices (SMD). It analyzes the theory of pull strength testing of solder joints with emphasis on standard IEC 62137-1-3 and describes the selection of components utilized to create mechanical construction and electrical parts. These electronic parts made or innovated in this work were control system based on microcontroler Atmega164P, power circuit for stepper motor and communication of measure equipment TEST 321 with PC. The whole design is complemented by simulation of mechanical stress to the critical components using ANSYS. The conclusion summarizes the most important parameters of this equipment.

The project deals with the overall design and construction of equipment called the desiccators for brazing in a protective atmosphere. The device was designed and manufactured cooling and heating element. For the soldering various temperature profiles have been defined and adjusted, as for SnPb as well for lead-free solders. There was a realization of samples were measured and analyzed. Finally were realized micro sections for lead free solder.

This thesis examines the inuence of nitrogen atmosphere on the quality of the solder joint lead-free solder paste. For the solder paste were measured and set temperature proles. Thesis includes the implementation and measurement of samples in a protective nitrogen atmosphere and without a protective atmosphere. These measurements are compared, and the conclusions were drawn for the inuence of nitrogen atmosphere. The reliability and the quality of the soldered joints were investigated.