Design, materials, and assembly process of high‐density packages with a low‐temperature lead‐free solder (SnBiAg)

Lau, John H.; Gleason, Jerry; Schroeder, V.; Henshall, G.A.; Dauksher, Walter; Sullivan, Bob

doi:10.1108/09540910810871520

Cited by 11 publications

(9 citation statements)

References 6 publications

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“…It should be emphasized that the “reliability” obtained from DFR as shown in Lau et al (2008) is not the same as the reliability (probability) obtained from reliability tests. For example, the life (number of cycle‐to‐failure) of the solder joint from reliability tests depends on the percent failed (or survived), i.e.…”

Section: Introductionmentioning

confidence: 93%

“…Most reliability tests are very expensive and time consuming. Thus, before and after the reliability testing, design for reliability (DFR) and failure analysis (FA), respectively, have been very useful and important tools for investigating/establishing/improving solder joint reliability, as shown in Figure 1 of Lau et al (2008).…”

Section: Introductionmentioning

confidence: 99%

“…As shown in Figure 1 of Lau et al (2008), right after the reliability tests, FA should then be done on the failed samples to understand the reason for their failure. This information is very useful for:providing the failure locations, failure modes, and failure mechanisms;verifying the reliability test data;verifying the DFR analysis results;understanding why it failed and how to fix it (or do better);for the next round of DFR and reliability testing; andchoosing acceleration models to determine the acceleration factors since most of the reliability tests are naturally “accelerated”.In this paper, temperature cycling and shock and vibration tests on high‐density lead‐free packages assembled on printed circuit boards (PCBs) with a SnBiAg solder paste are reported and the failed samples are analyzed.…”

Section: Introductionmentioning

confidence: 99%

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Reliability test and failure analysis of high‐density packages assembled with a low‐temperature lead‐free solder (SnBiAg)

Lau

Gleason²,

Schroeder³

et al. 2008

Soldering &Amp; Surface Mount Technology

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PurposeThe High Density Packaging Users Group Consortium has conducted a study of process development and solder‐joint reliability of high‐density packages on printed circuit boards (PCB) using a low‐melting temperature lead‐free solder. The purpose of this paper is to investigate the reliability tests (e.g. temperature cycling and shock and vibration) and failure analysis (FA) of high‐density packages on PCB with the low‐melting temperature lead‐free solder (Sn‐57 wt%Bi‐1 wt%Ag).Design/methodology/approachThe design for reliability, materials, and assembly process aspects of the project have been discussed in “Design, materials, and assembly process of high‐density packages with a low‐temperature lead‐free solder (SnBiAg)” also published in this journal issue. In this study, reliability tests (e.g. temperature cycling and shock and vibration) and FA of high‐density packages on PCB with the low‐melting temperature lead‐free solder (Sn‐57 wt%Bi‐1 wt%Ag) are investigated.FindingsLead‐free solder‐joint reliability of high‐density packages, such as the PBGA388, PBGA256, PBGA208, PBGA196, PBGA172, PQFP80, and TSSOP56 were determined by temperature cycling, shock, and vibration tests. Temperature cycling test data for over 8,100 cycles between 0 and 100°C in a 44 min. cycle were statistically analyzed. Shock and vibration test data based on the HP Standard Class Bi‐II Products SPEC have also been reported.Originality/valueCurrently there is a lack of experimental and simulation data and field experience in respect of one of the critical issues for industry – that of solder joint reliability in lead‐free soldering. The paper contains some important research results and recommendations.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reliability test and failure analysis of high‐density packages assembled with a low‐temperature lead‐free solder (SnBiAg)

Lau

Gleason²,

Schroeder³

et al. 2008

Soldering &Amp; Surface Mount Technology

Self Cite

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“…Although BiSn solder joints have better mechanical strength than classical 63Sn37Pb solder joints, they are more brittle, and their fatigue resistance is also lower (Mei and Morris, 1992). However, these "defects" can be rectified by alloying a small amount of Ag (2 Wt.%) (Lau et al, 2008). As an advantage of its low melting point, the eutectic BiSn alloy has a low CTE value (15 ppm/°C), which is lower by one-third of that of eutectic PbSn.…”

Section: Introductionmentioning

confidence: 99%

Reliability studies of InnoLot and SnBi joints soldered on DBC substrate

Skwarek

Illés

Witek

et al. 2018

SSMT

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Purpose This paper aims to investigate the quality and reliability of solder joints prepared from Pb-free alloys on direct bounded Cu (DBC) substrates. Two types of solder alloys were studied: Sn90.95Ag3.8Cu0.7Sb1.4Ni0.15Bi3.0, with a high melting point of 225°C, and Sn42Bi58, with low a melting point of 138°C. Design/methodology/approach Capacitor components of size 1806 were soldered on DBC substrates by using convection reflow soldering and vacuum vapor-phase soldering technologies. A part of the samples was subjected to the thermal shock test. The structure of the solder joints and the content of the voids were investigated using three-dimensional X-ray tomography. The mechanical strength of the joints was evaluated using the shear force test, and the microstructure of the joints was studied on metallographic cross sections by using scanning electron microscopy. Findings It was found that the number of voids is not related directly to the mechanical strength of the solder joints. The mechanical strength of the solder joints depends more on the amount of Ag3Sn precipitation, Au precipitation and the intermetallic layer in the solder joints. In some cases, the thermal shock test caused micro-cracks around the Au precipitation because of a mismatch of Au, AuSn4 and Sn in terms of coefficients of thermal expansion. Originality/value DBC substrates are usually used for power electronics, where the quality of the solder joints is even more important than in the case of commercial electronics.

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“…By adding elements as silver the SnBi alloy's ductility can be improved [2]. As a result, alloys of the composition SnBi57Ag1 have a high potential for application in SMT [3].…”

Section: Introductionmentioning

confidence: 99%

Computed-Tomography-Based Analysis of Voids in SnBi57Ag1 Solder Joints and Their Influence on the Reliability

Rauer

Volkert

Schreck

et al. 2014

J Fail. Anal. and Preven.

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The first area of research in this article focuses on the characterization of solder joints that contain voids by means of computed tomography (CT). This non-destructive test method made it possible to detect both cracks and voids in solder joints, to define their precise positions, and to capture the void volume of each void. In addition to CT, we carried out metallographic examinations so that we could demonstrate the interaction of both methods. In the process, CT was used to localize the defect and metallography to display the defect in high resolution. The article goes on to discuss the question of whether voids have an effect on the thermo-mechanical reliability of SnBi57Ag1 solder joints. For this purpose, the solder joints were first classified by their void area ratio using radioscopy. In order to analyze the effect of the void area ratio on the reliability of the joint, the assembly underwent an accelerated aging process through thermal shock testing according to IPC 9701. Subsequently, the shocked assemblies were sheared. With the shear values after 1000 cycles, we were able to show that the voids affect the reliability of the SnBi57Ag1 solder joints only slightly and that the joints were hardly damaged. By means of CT examinations performed prior to the thermal shocks, cracks starting from the meniscus tip could be attributed to the temperature changes. These cracks may be crucial when they occur with cracks found on macrovoids inside the meniscus.

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Design, materials, and assembly process of high‐density packages with a low‐temperature lead‐free solder (SnBiAg)

Cited by 11 publications

References 6 publications

Reliability test and failure analysis of high‐density packages assembled with a low‐temperature lead‐free solder (SnBiAg)

Reliability test and failure analysis of high‐density packages assembled with a low‐temperature lead‐free solder (SnBiAg)

Reliability studies of InnoLot and SnBi joints soldered on DBC substrate

Computed-Tomography-Based Analysis of Voids in SnBi57Ag1 Solder Joints and Their Influence on the Reliability

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