Humidity-related failures in electronics: effect of binary mixtures of weak organic acid activators

Piotrowska, Kamila; Verdingovas, Vadimas; Ambat, Rajan

doi:10.1007/s10854-018-9896-0

Cited by 32 publications

(18 citation statements)

References 50 publications

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“…It has been reported that dicarboxylic acids used as activators have a hygroscopic nature, thus enhance the condensation probability, 9,10 which is even more severe if they are present in binary mixtures. 11 Similar results have been reported with wave soldering fluxes containing dicarboxylic acids. 9,12 Furthermore, the thermal decomposition of typical WOAs (succinic acid, glutaric acid, adipic acid, suberic acid, DL-malic acid and palmitic acid) and containing wave soldering fluxes have been studied within simulated wave soldering conditions.…”

Section: Introductionsupporting

confidence: 78%

Investigation of the Effect of Temperature on the Properties of No-Clean Reflow Soldering Fluxes

Gacs¹,

Kocsis²,

Németh³

et al. 2020

Journal of Elec Materi

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With the decreasing size of microelectronics, corrosion-related reliability issues have become more abundant. The presence of no-clean soldering flux residues has been commonly identified as an accelerating factor for electrochemical corrosion. This paper discusses the investigation of five different commercially available no-clean fluxes, used in reflow solder pastes. At first, the initial composition and thermal behavior of the systems were characterized with gas chromatography (GC-MS) and thermogravimetric analysis. Based on the results, no differences were identified between the evaporation characteristics of the fluxes in nitrogen and in air up to 250°C. After initial investigation, the real-life thermal decomposition behavior, pH-and conductivity-changing capability of the fluxes were emulated in the temperature range of 50-250°C. To identify the potential specific effect of copper, the experiments were conducted with both direct bonded copper and glass substrates. No specific effect of copper was detected regarding the remaining amount of flux residue on the surface. Furthermore, after treating the samples at 250°C, no significant pH-or conductivity-changing capability was identified in the case of any of the investigated flux systems regardless of the substrate. Based on these results, the necessity of the follow-up cleaning steps must be reconsidered.

show abstract

Section: Introductionsupporting

confidence: 78%

Investigation of the Effect of Temperature on the Properties of No-Clean Reflow Soldering Fluxes

Gacs¹,

Kocsis²,

Németh³

et al. 2020

Journal of Elec Materi

View full text Add to dashboard Cite

show abstract

“…The mixtures had two components, with one exhibiting a higher affinity towards moisture (hygroscopicity) than the other. Therefore, the increasing order of hygroscopicity for the blend ratios was as follows: 5:1 < 1:1 < 1:5 (Piotrowska et al , 2018b). The pure WOAs were dissolved in isopropyl alcohol (99.8 per cent purity) to give 0.3 per cent wt/v and 2.5 per cent wt/v solutions of the binary mixtures of each ratio.…”

Section: Methodsmentioning

confidence: 99%

“…The leakage current was measured at each RH while varying the potential from 0 to 10 V at a sweep rate of 2 mV/s using a Bio-Logic VSP potentiostat. A detailed description of the test method can be found elsewhere (Piotrowska et al , 2018a) (Piotrowska et al , 2018b).…”

Section: Methodsmentioning

confidence: 99%

“…Activators are the chemicals that react with the metal oxides and allow for the formation of a strong metallurgical bond between the joint and molten solder. However, there are also the flux components that contribute to corrosion failures in electronics exposed to humid conditions (Verdingovas et al , 2015a) (Verdingovas et al , 2013) (Jellesen et al , 2012) (Verdingovas et al , 2015b) (Verdingovas, 2012) (Piotrowska et al , 2018b). Due to the hygroscopic nature of WOAs, the adsorption and absorption of moisture on the PCBA surface is facilitated (Verdingovas et al , 2013) at the critical relative humidity (RH) levels characteristic for each WOA.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the range of temperatures that can be experienced by the residues during the soldering process defines the residual contamination level (Jellesen et al , 2010). The physicochemical properties of activators, namely the critical RH, solubility, and dissociation constant (pK a ), become meaningful in connection with the humid conditions, where the risk of ECM exists (Piotrowska et al , 2018a) (Piotrowska et al , 2018b).…”

Section: Introductionmentioning

confidence: 99%

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Thermal decomposition of binary mixtures of organic activators used in no-clean fluxes and impact on PCBA corrosion reliability

Piotrowska

Ambat

2019

SSMT

Self Cite

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Purpose The purpose of this paper is to investigate the decomposition behavior of binary mixtures of organic activators commonly used in the no-clean wave flux systems upon their exposure to thermal treatments simulating wave soldering temperatures. The binary blends of activators were studied at varying ratios between the components. Design/methodology/approach Differential scanning calorimetry and thermogravimetric analysis were used to study the characteristics of weak organic acid (WOA) mixtures degradation as a function of temperature. The amount of residue left on the surface after the heat treatments was estimated by gravimetric measurements as a function of binary mixture type, temperature and exposure time. Ion chromatography analysis was used for understanding the relative difference between decomposition of activators in binary blends. The aggressivity of the left residue was assessed using the acidity indication gel test, and effect on reliability was investigated by DC leakage current measurement performed under varying humidity and potential bias conditions. Findings The results show that the typical range of temperatures experienced by electronics during the wave soldering process is not sufficient for the removal of significant activator amounts. If the residues contain binary mixture of WOAs, the final ratio between the components, the residue level and the corrosive effects depend on the relative decomposition behavior of individual components. Among the WOA investigated under the conventional wave soldering temperature, the evaporation and removal of succinic acid is more dominant compared to adipic and glutaric acids. Practical implications The findings are attributed to the chemistry of WOAs typically used as flux activators for wave soldering purposes. The results show the importance of controlling the WOA content and ratio between activating components in a flux formulation in relation to its tendencies for evaporation during soldering and the impact of its residues on electronics reliability. Originality/value The results show that the significant levels of flux residues can only be removed at significantly higher temperatures and longer exposure times compared to the conventional temperature range used for the wave soldering process. The potential corrosion issues related to insufficient flux residues removal will be determined by the residue amount, its composition and ratio between organic components. The proper time of thermal treatment and careful choice of fluxing formulation could ensure more climatically reliable product.

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Air Sensitivity and Degradation Evolution of Halide Solid State Electrolytes upon Exposure

Wang

Cui

et al. 2021

Adv Funct Materials

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Halide solid state electrolytes (SSEs) have attracted the attention of researchers as a new family of SSEs due to simple synthesis, high ionic conductivity, and good softness. However, until now, most of the reported works are focused on promotion of ionic conductivity, and little attention is paid to their air stability and degradation mechanism upon exposure. Herein, the degradation evolution of typical halide SSEs upon moisture is investigated in detail. It is found both Li 3 InCl 6 and Li 3 YCl 6 halide SSEs are easy to absorb water and deteriorate, and the air sensitivity is closely related to the contact area with air. In comparison, the water absorption rate of Li 3 InCl 6 is faster than that of Li 3 YCl 6 , while the amount of water absorption of Li 3 YCl 6 is larger than that of Li 3 InCl 6 , due to the higher solubility of InCl 3 compared to YCl 3 . Along with water absorption, Li 3 InCl 6 first forms a crystalline hydrate, then partially decomposes to InCl 3 and LiCl, and InCl 3 further hydrolyzes and produces acid which is corrosive; finally In 2 O 3 impurities are formed. Coating the surface of Li 3 InCl 6 with Al 2 O 3 can effectively improve the air stability. This work can help to understand the degradation mechanism of halide SSEs and provide guidance for the future design of new halide SSEs.

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Humidity-related failures in electronics: effect of binary mixtures of weak organic acid activators

Cited by 32 publications

References 50 publications

Investigation of the Effect of Temperature on the Properties of No-Clean Reflow Soldering Fluxes

Investigation of the Effect of Temperature on the Properties of No-Clean Reflow Soldering Fluxes

Thermal decomposition of binary mixtures of organic activators used in no-clean fluxes and impact on PCBA corrosion reliability

Air Sensitivity and Degradation Evolution of Halide Solid State Electrolytes upon Exposure

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