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 high cycle fatigue (HCF) cracking behaviors in the SnPb solder joints were investigated experimentally via in situ observations with scanning electron microscope (SEM). The results indicate that the HCF cracks incubate at the toe of the solder joints and propagate mainly along an angle from 20 to 45 tilted to the applied stress axis differing greatly from the propagation behaviors reported ...

Miniaturisation of electronic equipment, such as those found in a notebook computer, palm held devices, cell phones etc., requires high-density packing of electronic components onto printed circuit boards (PCB). To join the interconnections, solder materials are used to bond microprocessor chips and board during assembly. In the Reflow process case, the board assembly passes through a furnace w...

The ultimate life of a microelectronics component is often limited by failure of a solder joint due to crack growth through the laminate under a contact pad (cratering), through the intermetallic bond to the pad, or through the solder itself. Whatever the failure mode proper assessments or even relative comparisons of life in service are not possible based on accelerated testing with fixed ampl...

This paper investigates methodologies for locating and identifying the components on a printed circuit board (PCB) used for surface mount device inspection. The proposed scheme consists of two stages: solder joint extraction and protective coating extraction. Solder joints are extracted by first detecting all the highlight areas, and then recognizing and removing the invalid highlight areas whi...

To better understand the effect of repeated reverse stress in solder joints, a new testing method was developed. Tin-silver solder joints were fabricated, constrained between Cu blocks, and then subjected to repeated shear loading in a tensile tester. Constant strain amplitudes were applied to simulate service conditions. However, large loads were used to accelerate the damage accumu­ lation. M...

Solder joints formed in microgravity are inferior to Earth gravity. They mechanically weaker and less electrically conductive due voids forming the when soldering microgravity. Surface tension lack of gravitational buoyancy combine prevent flux water vapors from escaping molten solder absence gravity, resulting more porous joints. Additionally, corrosive vapor products remain trapped causing fu...

Low-cycle, lap-shear fatigue behavior of Sn-based, Pb-free solder alloys, Sn3.5Ag, Sn-3.5Ag-Cu, Sn-3.5Ag-Bi, and Sn-0.7Cu, were studied at room temperature using specimens with printed circuit board (PCB)/solder/PCB structure under total displacement of ±10 μm, 12 μm, 15 μm, and 20 μm. The fatigue lives of various solder joint materials, defined as 50% load drop, were correlated with the fractu...

The near eutectic 60%-40Pb alloy is the most commonly used solder for electrical interconnections in electronic packages. This alloy has a number of processing advantages (suitable melting point of 183°C and good wetting behavior). However, under conditions of cyclic strain and temperature (thermomechanical fatigue), the microstructure of this alloy undergoes a heterogeneous coarsening and fail...