• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.122-122
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• 2009

금속기판과 액체금속의 젖음성은 일반적으로 액적법 (sessile drop)에 의해 고체와 액체간의 접촉각 측정을 통해서 알 수 있다. 이러한 방법에 의한 젖음성 실험결과는 고체와 액체계면에서의 반응이 무시될 수 있는 경우에 적용가는 하지만 연속용용도금공정과 같이 용융된 금속내부로 강판이 인입되는 과정에서 계면반응이 동적으로 진행되는 과정에서의 젖음성을 모사하기에는 이러한 방법의 신뢰성이 떨어지는 문제점이 있다. 따라서 본 연구에서는 실제 용융도금공정과 유사하게 소둔열처리된 저탄소강판이 환원성분위기내에서 Zn 및 Zn-Al 용융도금욕 내부로 연속적으로 인입되는 과정에서의 젖음력 및 접촉각 등의 측정을 통해 실제 도금공정상의 도금성과 젖음성의 연관성을 규명하고자하였다. 연구결과 일반적인 Zn 도금욕의 경우 젖음성이 양호하지만 Al함량이 높은 경우에는 젖음성이 좋지 못한 것으로 나타났다.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.4
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• pp.7-15
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• 2000

The purpose of this work is to evaluate the solderahility and characteristics of solder joints. Bridge defect of solder joint was examined in natural atmosphere and $N_2$ condition. Consequently, wettability was excellent for each of Sn-Pb plated Cu specimen, Sn plated Cu specimen, and Cu polished in $N_2$ condition. The wetting time in $N_2$ condition was shorter than that of natural atmosphere condition, showing the decreasing values of about 0.2~0.45 seconds. The max. wetting force under the $N_2$ condition was more increasing that of natural atmosphere condition, showing the increasing values of about 1.8~2.8 N. With the result of wetting balance test, the wetting time ($t_2$) and wetting farce according to increasing amount of $N_2$ from 10 1/min to 30 1/min, the wetting time ($t_2$) was reduced about 0.25 second and wetting force was increased about 2.3 N. In non-cleaning flux, when $N_2$ gas is applied, it is compensated to decrease of wettability. In the case of using the $N_2$ gas, the wettability was improved. The reason for improving wettability is due to preventing the formation of dross. The generation rate of bridge in $N_2$ condition decreased than that of natural atmosphere, and when the specimen had a fine pitch, the rate of bridge defects was considerably decreased in $N_2$ condition, showing the decreasing rate of 25~75%.

• Journal of Welding and Joining
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• v.16 no.6
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• pp.77-85
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• 1998

Effects of non-cleaning and cleaning fluxes on the wetting properties and defects at flow soldered joints were investigated. Non-cleaning flux (R-type of 3.3% solid content) and cleaning flux (RMA-type of 15% solid content) were used. Wetting test was accomplished by wetting balance method with changing surface state of wetting specimen, CU. Sn-37%Pb solder was used for wetting test and flow soldering. As experimental results, the wetting time for vertical force from the surface tension being zero was mainly affected by surface state of the wetting specimen. Non-cleaning flux had a good wettability compared with cleaning flux. In case of non-cleaning flux, conveyor speed had a great affection to defects of bridge, icicle, and poor solder.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.83-90
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• 2017

In this paper, we evaluated the solderability of thin electroless nickel-electroless palladium-immersion gold (ENEPIG) plating layer for fine-pitch package applications. Firstly, the wetting behavior, interfacial reactions, and mechanical reliability of a Sn-3.0Ag-0.5Cu (SAC305) solder alloy on a thin ENEPIG coated substrate were evaluated. In the wetting test, maximum wetting force increased with increasing immersion time, and the wetting force remained a constant value after 5 s immersion time. In the initial soldering reaction, $(Cu,Ni)_6Sn_5$ intermetallic compound (IMC) and P-rich Ni layer formed at the SAC305/ENEPIG interface. After a prolonged reaction, the P-rich Ni layer was destroyed, and $(Cu,Ni)_3Sn$ IMC formed underneath the destroyed P-rich Ni layer. In the high-speed shear test, the percentage of brittle fracture increased with increasing shear speed.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.1
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• pp.59-64
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• 1999

This paper investigated optimum drying time of PCB and the relationship between humidity in PCB and solderability. As experimental results, soldering was improved with increasing drying time. The wetting time of a dry specimen was shorter about 0.2 seconds than that of a wet specimen. The wetting force was Increased by 2~4mN after drying the wet specimen. When PCB was dried over 30 minute, solder defects and tensile strength of soldered joints was optimized. Effects of drying tome of PCB on the soldering, wetting curve, soldered shape, solder ball, and tensile strength, were investigated.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.123-128
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• 2018

Effect of activators in flux on the printability and wettability of a solder paste was evaluated in this study. The activators in this study were dicarboxylic acids, which were oxalic acid (n = 0), malonic acid (n = 1), succinic acid (n = 2), glutaric acid (n = 3), adipic acid (n = 4), and pimelic acid (n = 5). When the solder pastes were observed with a SMT scope, solder with glutaric acid showed clean and shiny surface when it was melted. Slump ratio of the solder pastes was low when the carbon numbers of the dicarboxylic acid were 1-3. Spreadability was high when the carbon number was over 2. Zero cross time of wetting balance test was under 1 sec when the carbon number was over 3. When activator was oxalic acid or malonic acid, zero cross time was over 1 sec and maximum wetting force was low. Fluxes with the oxalic acid and malonic acid showed decomposition at the temperature close to melting point. Among the dicarboxylic acids, glutaric acid provided excellent slump, spreadability, and wettability.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.43-47
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• 2001

Sn-3Ag-8Bi-5In was developed for the intermediate melting point solder. Although In-contained solder is expensive, its melting point is lower than these of Sn-Ag-Cu alloys. Sn-3Ag-8Bi-5In solder used for this research has a melting range of 188~$204^{\circ}C$. On this study wetting characteristics of Sn-3Ag-8Bi-5In were evaluated in order to investigate its availability as a Pb-free solder. Wettabilities of Sn-37Pb and Sn-3.5Ag solders were also studied to compare these of the Sn-3Ag-8Bi-5In. Experimental results showed that the zero-cross-time and wetting time at $240^{\circ}C$ for the Sn-3Ag-8Bi-5In were 1.1 and 2.2 second respectively. These values are a little better than these of Sn-37Pb and Sn-3.5Ag solders. The equilibrium wetting farce of the Sn-3Ag-8Bi-5In was 5.8 mN at $240^{\circ}C$, and it was tuned out to be a little higher than that of Sn-3.5Ag and lower than that of Sn-37Pb.