The influence of voids in solder joints on thermal performance and reliability investigated with transient thermal analysis

Hanß, Alexander; Liu, E; Schmid, Maximilian; Elger, Gordon

doi:10.1109/therminic.2015.7389623

Cited by 16 publications

(4 citation statements)

References 3 publications

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“…Equation ( 3) is used on all, and the normalization is performed in an interval from 100 to 1000 µs. The region of interest is the highest peak, where an increase of 0.05 can be interpreted as a failure [43][44][45]. Zth(t) is calculated afterward from ΔTJ(t) and the power step from PHeat to PSense with Equation ( 1), and it is the basis for any evaluation in TTA.…”

Section: Transient Thermal Analysis (Tta)mentioning

confidence: 99%

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Comparison of Nondestructive Testing Methods for Solder, Sinter, and Adhesive Interconnects in Power and Opto-Electronics

et al. 2020

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Reliability is one of the major requirements for power and opto-electronic devices across all segments. High operation temperature and/or high thermomechanical stress cause defects and degradation of materials and interconnects, which may lead to malfunctions with costly or even life-threatening consequences. To avoid or at least reduce failures, nondestructive testing (NDT) methods are common within development and production of power and opto-electronics. Currently, the dominating NDT methods are X-ray, scanning acoustic microscopy (SAM), and transient thermal analysis (TTA). However, they have different strengths and weaknesses with respect to materials and mechanical designs. This paper compares these NDT methods for different interconnect technologies, i.e., reflow soldering, adhesive, and sintered interconnection. While X-ray provided adequate results for soldered interfaces, inspection of adhesives and sintered interconnects was not possible. With SAM, evaluation of adhesives and sintered interconnects was also feasible, but quality depended strongly on the sample under test. TTA enabled sufficiently detailed results for all the interconnect applications. Automated TTA equipment, as the in-house developed tester used within this investigation, enabled measurement times compatible with SAM and X-ray. In the investigations, all methods revealed their pros and cons, and their selection has to depend on the sample under tests and the required analysis depth and data details. In the paper, guidelines are formulated for an appropriate decision on the NDT method depending on sample and requirements.

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Section: Transient Thermal Analysis (Tta)mentioning

confidence: 99%

“…An exemplary evaluation of the data can be seen in Figure 4b with the same dataset as in Figure 4a. Equation ( 3) is used on all, and the normalization is performed in an interval from 100 to 1000 µ s. The region of interest is the highest peak, where an increase of 0.05 can be interpreted as a failure [43][44][45].…”

Section: Transient Thermal Analysis (Tta)mentioning

confidence: 99%

Comparison of Nondestructive Testing Methods for Solder, Sinter, and Adhesive Interconnects in Power and Opto-Electronics

et al. 2020

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“…This allowed the detection of errors in the solder joint, like voids or not wetted pad. Voids decrease the thermal performance of the LED module, and therefore reduce the lifetime of the LEDs (Hanss et al, 2015).…”

Section: Solder Joint Inspection By X-raymentioning

confidence: 99%

Residual free solder process for fluxless solder pastes

Hanß

Elger

2018

SSMT

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Purpose For soldering, flux is essential because it enables the wetting of the molten solder. Fluxless soldering, i.e. residue-free soldering with the aid of gaseous activators, has been known for many years, but is only well established in the field of opto- and microwave electronics where the solder is applied as preform. In high-volume SMD applications where solder paste is printed, this technology is rarely used until now. The reducing effect of a gaseous activator like formic acid vapor on certain solder alloys is known in practice. However, the corresponding reactions which occur under soldering conditions in nitrogen atmosphere have so far not been systematically investigated for different solder alloys. This study aims to analyze the different chemical reaction channels which occur on the surface of different solders, i.e. catalytical dissociation of formic acid on the pure or oxidized metal surface and the formation and evaporation of metal formates. Based on this analysis, a residue-free solder process under formic acid is developed for solder paste applications. Design/methodology/approach In this paper, different solder alloys (SnAgCu, SnPb, BiSn, In) were analyzed with thermal gravimetric analysis (TGA) under formic acid flow. Details on mass change depending on the soldering temperature are presented. Activation temperatures are estimated and correlated to the soldering processes. Based on the analysis, fluxless solder pastes and suitable soldering processes are developed and presented. Major paste properties such as printability are compared to a commercial flux solder paste. High-power flip chip LEDs which can be assembled directly on a printed circuit board are used to demonstrate the fluxless soldering. Likewise, the soldering results of standard paste and fluxless paste systems after a reflow process are evaluated and compared. Findings The experimental results show that TGA is an efficient way to gain deeper understanding of the redox processes which occur under formic acid activation, i.e. the formation of metal formates and their evaporation and dissociation. It is possible to solder residue-free not only with preforms but also with a fluxless solder paste. The resulting solder joints have the same quality as those for standard solder paste in terms of voids detected by X-ray and mechanical shear strength. Originality/value In the fluxless soldering process, the reduction of oxide layers, and therefore the wetting of the solder spheres, is enabled by gaseous formic acid. After the soldering process, no cleaning process is necessary because no corrosive residues are left on the circuit boards and components. Therefore, soldering using solder paste without aggressive chemical ingredients has a high market potential. Expensive preforms could be replaced by paste dispensing or paste printing.

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“…On the other hand, the thermo-mechanical reliability of these components has been a focal point of research [ [4] , [5] , [6] , [7] , [8] ]. The performance of FCLEDs relies heavily on the material of the FCLED, the interconnecting solder material, and the substrate material of the printed circuit board (PCB).…”

Section: Introductionmentioning

confidence: 99%

Effect of solder void on mechanical and thermal properties of flip-chip light-emitting diode: Statistical analysis based on finite element modeling

Jo,

Sim,

Park

et al. 2024

Heliyon

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The influence of voids in solder joints on thermal performance and reliability investigated with transient thermal analysis

Cited by 16 publications

References 3 publications

Comparison of Nondestructive Testing Methods for Solder, Sinter, and Adhesive Interconnects in Power and Opto-Electronics

Comparison of Nondestructive Testing Methods for Solder, Sinter, and Adhesive Interconnects in Power and Opto-Electronics

Residual free solder process for fluxless solder pastes

Effect of solder void on mechanical and thermal properties of flip-chip light-emitting diode: Statistical analysis based on finite element modeling

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