This Note describes the suitability of a number of techniques of potential use in studying cracking in lead-free solder joints, and hence their use in assessing joint lifetimes. Cracks induced into solder joints of chip resistors on FR4 substrates, were studied using micro-sectioning, dye penetration, mechanical test and thermal conductivity techniques. The work previously reported [1] has been...

To improve a cost performance and the reliability of PC boards, an inspection of BGA is required in the surface mount process. Types of defects at BGA solder joints are solder bridges, missing connections, solder voids, open connections and miss-registrations of parts. As we can find mostly solder bridges in these defects, we pick up this to detect solder bridge in a production line. The proble...

The trend of miniaturization, light weight, high speed and multifunction are common in electronic assemblies, especially, for portable electronic products. In particular, board-level solder joint reliability, in term of both mechanical (e.g., drop impact) and thermo-mechanical (e.g., thermal cycling) loads is of great concern for portable electronic products. The transition to lead-free solder ...

A submodeling technique using MSC/PATRAN program and ABAQUS nonlinear finite element code, combined with a Taguchi design-of-experiments approach, was used to optimize the shear strength of spherical ball attachment on an aluminum nitride substrate. In the current design, the sphere is brazed onto a gold solder pad on the backside of the substrate using a gold-tin solder. In the present study, ...

For electronic products, interconnect failures may occur due to mechanisms such as fatigue, creep, corrosion, and mechanical over-stress. Regardless of the failure mechanism, interconnect degradation often starts at a surface and propagates inward. DC resistance, which has been used by the electronics industry to monitor the reliability of board level interconnects, does not offer an adequate m...

Solder joint reliability of SMT components connected to printed circuit boards is well documented. However, much of the testing and data is related to high-strain energy thermal cycling experiments relevant to product qualification testing (i.e., -55C to 125C). Relatively little information is available on low-strain, high-cycle fatigue behavior of solder joints, even though this is increasingl...

Board-level solder joint reliability is very critical for handheld electronic products during drop impact. In this study, board-level drop test and finite element method (FEM) are adopted to investigate failure modes and failure mechanisms of lead-free solder joint under drop impact. In order to make all ball grid array (BGA) packages on the same test board subject to the uniform stress and str...

The solder joint reliability of ceramic chip resistors assembled to laminate substrates has been a long time concern for systems exposed to harsh environments such as those found in automotive and aerospace applications. This is due to a combination of the extreme temperature excursions experienced by the assemblies along with the large coefficient of thermal expansion mismatches between the al...

This paper describes the interaction of the NEMI recommended lead-free solder for reflow assembly (Sn3.8Ag0.7Cu) with different commercial printed wiring board (PWB) platings. It also discusses the effects of plating type and manufacturer on the strength of the lead-free solder joints. PWBs from two different manufacturers with the same four types of plating were examined. The platings were org...

The effects of a third element, namely silver, copper, zinc, or antimony, on the microstructure and mechanical properties of eutectic tin-bismuth (Sn–Bi) solder were investigated. The investigation showed that, except for zinc, the addition of a trace amount of the third element improves the ductility of the Sn–Bi solder owing to the formation of a fine, homogeneous ternary eutectic microstruct...