In this study, interfacial reactions of electrolytic Ni and electroless Ni(P) metallization of the ball-grid-array (BGA) substrate with the molten n–9Zn (wt.%) eutectic solder alloy were investigated, focusing on the shear strengths and the identification of the intermetallic compound IMC) phases at various reflow periods. Zn-containing Pb-free solder alloys were kept in molten condition (240 ◦...

A new method of assembling MEMS is being developed that uses solder surface tension force to manipulate and assemble MEMS 3-D structures. Modeling is critical to design solder joints for precision assembly. An accurate model has been developed based on the principle of surface energy minimization. Using Surface Evolver software, this model considers three-dimensional MEMS configurations with di...

Title of Document: EFFECTS OF SOLDER-DIPPING AS A TERMINATION RE-FINISHING TECHNIQUE Shirsho Sengupta, M.S., Mechanical Engineering, June 2006 Directed By: Prof. Michael G. Pecht, Chair Professor, Mechanical Engineering Solder-dipping may be used to replace tin-rich finishes with eutectic tin-lead for tinwhiskering risk mitigation purposes. However, re-finishing also subjects electronic parts t...

Surface-micromachined microelectromechanical systems (MEMS) are two dimensional in their “as fabricated” form. Surface-micromachined MEMS can be assembled after fabrication to realize systems with a more three-dimensional form and function. One reliable method of assembly, suited to commercial mass production, is to use the surface tension of microsized droplets of molten solder to assemble the...

Using detailed finite element models, a fracture analysis of solder bumps and under bump metallurgy (UBM) in flip-chip packages is carried out. Our objective is to identify likely fracture modes and potential delamination sites at or near these microstructural components. In order to study flip-chips, whose dimension spans from sub-micron thickness UBM layers to several millimeters wide package...

The integration and miniaturization trend of the electronic packaging leads to much finer pitch of the device and package lead terminations. Several reliability concerns and issues that were previously not encountered are now surfacing. The objective of this thesis work is to investigate the reliability of the package-to-board interconnection from the perspective of solder joint metallurgy. It ...

Objective(s) To determine the potential toxic effects of manual soldering flux cored solder wire on lung of the rat as an experimental model. Materials and Methods A total number of 48 adult male rats were divided into experimental (n= 30) and control (n= 18) groups. Based on exposure time to solder fume, each group was further subdivided into 2, 4 and 6 week subgroups. Rats of experimental ...

Recent investigations have revealed that Pb-free solder joints may be fragile, prone to premature interfacial failure particularly under shock loading, as initially formed or tend to become so under moderate thermal aging. Depending on the solder pad surface finish, different mechanisms are clearly involved, but none of the commonly used surface finishes appear to be consistently immune to embr...

S ince the advent of through-hole printed wiring boards in the 1950s, surface-mount technology has advanced through chip capacitors and resistors to high-density multilayer hybrids and printed circuit boards. Throughout this 40-year span, solder paste has been the accepted technology for component attach.' The present trend toward fine-pitch resolution ( t0.020") and multilayer constructions of...

Title of Document: CONSTITUTIVE PROPERTY TESTING AND RELIABILITY ASSESSMENT OF LEADFREE SOLDER JOINT Yuri Lee, Master, 2010 Directed By: Professor Bongtae Han, Department of Mechanical Engineering A modified single lap shear test configuration, based on the Iosipescu geometry, is proposed to characterize mechanical properties of solder alloys. In the method, an auxiliary device (extension unit)...