• Title/Summary/Keyword: wetting test

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Wettability Evaluation by Wetting Balance Test and Wetting Characteristics of Solders (웨팅밸런스법을 통한 젖음성 평가와 솔더의 젖음 특성)

  • Jeon, Wook Sang;Rajendran, Sri Harini;Jung, Jae Pil
    • Journal of the Microelectronics and Packaging Society
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    • v.26 no.3
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    • pp.1-6
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    • 2019
  • Wettability is an important factor to decide solderability of solder, flux, other soldering-related materials and soldering conditions. The wettability also affects the reliability of solder joint. Wetting balance test is a good method for quantitatively measuring wettability between solder and substrate. The wetting balance test is easy to reproduce the wetting experiment and to measure the wetting time and force. And this test provides wetting curve to calculate the surface tension of the molten solder. Development of new solder has been continued in accordance with various and harsh environment in the electronics industry. In this paper, the principle of wetting balance test and recent research issues including nano-composite solder are explained.

Wettability Analysis of Solders using Wetting Balance Test (Wetting Balance Test를 이용한 솔더의 젖음성 분석)

  • Jung, Do-hyun;Lim, Dong-uk;Baek, Bum-gyu;Yim, Song-hee;Yoon, Jong-hyuk;Jung, Jae Pil
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.2
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    • pp.1-9
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    • 2017
  • Recently, there has been a continuous researches on solders having sophisticated and improved performance due to demand for high-density and miniaturization of electronics, and development of solder for automotive electronics which can be used in harsh environment. When developing a new solder alloy, there is a wettability of solder on substrate for things to consider, and the wetting balance test is one of the methods for measuring that one. In this paper, the wetting balance test is introduced, and the calculus of the surface tension of solder and the contact angle between solder and substrate using wetting curve obtained is introduced too. In detail, the principle and test method of the wetting balance test, the introduction of the parameters with important meaning in the wetting curve, the method of calculating the contact angle as well as the surface tension of the solder using the shape of the solder meniscus.

A Study on Wettability and Defects Behavior of Flow-soldered Joint using Low Residue Flux (저잔사 플럭스를 사용한 플로우 솔더링부의 젖음성 및 결함거동에 관한 연구)

  • 최명기;이창열;정재필;서창제;신영의
    • 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.

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The Fluxless Wetting Properties of TSM-coated Glass Substrate to the Pb-free Solders (TSM(Top Surface Metallurgy)이 증착된 유리기판의 Pb-free 솔더에 대한 무플럭스 젖음 특성)

  • 홍순민;박재용;박창배;정재필;강춘식
    • Journal of the Microelectronics and Packaging Society
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    • v.7 no.2
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    • pp.47-53
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    • 2000
  • The fluxless wetting properties of TSM-coated glass substrate were evaluated by the wetting balance method. We could estimate the wettability of the TSM with new parameters obtained from the wetting balance test for one side-coated specimen. It was more effective in wetting to use Cu as a wetting layer and Au as a protection layer than to use Au itself as a wetting layer. The SnSb solder showed better wettability than SnAg, SnBi, and SnIn solders. The contact angle of the one side-coated glass substrate to the Pb-free solders could be calculated from the farce balance equation by measuring the static force and the tilt angle.

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The Fluxless Wetting Properties of UBM-Coated Si-Wafer to the Pb-Free Solders (UBM이 단면 증착된 Si-Wafer에 대한 Pb-free 솔더의 무플럭스 젖음 특성)

  • 홍순민;박재용;김문일;정재필;강춘식
    • Journal of Welding and Joining
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    • v.18 no.6
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    • pp.74-82
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    • 2000
  • The fluxless wetting properties of UBM-coated Si-wafer to the binary lead-free solders(Sn-Ag, Sn-Sb, Sjn-In, Sn0Bi) were estimated by wetting balance method. With the new wettability indices from the wetting curves of one side coated specimen, the wetting property estimation of UBM-coated Si-wafer was possible. For UBM of Si-chip, Au/Cu/Cr UBm was better than au/Ni/TI in the point of wetting time/ At general reflow process temperature, the wettability of high melting point solders(Sn-Sb, Sn-Ag) was better than that of low melting point one(Sn-Bi, Sn-In). The contact angle of the one side coated Si-plate to the solder could be calculated from the force balance equation by measuring the static state force and the tilt angle.

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Changes in Absorbency and Drying Speed of a Quick-drying Knit Fabric by Repeated Laundering

  • Roh, Eui-Kyung;Kim, Eun-Ae
    • Journal of the Korean Society of Clothing and Textiles
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    • v.34 no.12
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    • pp.2062-2072
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    • 2010
  • This research evaluates the change of the water absorbency and drying speed of a quick-drying knit fabric by repeated laundering and laundering conditions and investigates the influence of laundering conditions on the functional properties of the knit fabric. Four factors of laundering conditions were studied: detergent, water hardness, water temperature, and frequency of rotation. Knit fabrics were washed for 25 laundering cycles in a drum-type washing machine with nine different laundering conditions derived from an orthogonal array. The properties of knit fabrics were measured with a drop absorption test, a strip test, and a drying time test. Relaxation shrinkage pointed to a change in the structural characteristics of the knit fabric. Wetting time was faster and wickability was greater in the knit fabrics that underwent 5 laundering cycles; in addition, there were no obvious changes in wetting time and wickability. The detergent was the most important factor in wetting time (40.4%) and wickability (60% or above). Water hardness, water temperature and RPM had less of an effect on wetting time and wickability. There were no significant differences between the levels of laundering conditions (except for detergent) on wetting time and wickability. Drying times with neutral and alkali were slower by repeated laundering; however, there was no obvious change in drying time. Hardness, water temperature and RPM had less of an impact on drying time.

A Study on the Wetting Properties of UBM-coated Si-wafer (UBM(Under Bump Metallurgy)이 단면 증착된 Si-wafer의 젖음성에 관한 연구)

  • 홍순민;박재용;박창배;정재필;강춘식
    • Journal of the Microelectronics and Packaging Society
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    • v.7 no.2
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    • pp.55-62
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    • 2000
  • The wetting balance test was performed in an attempt to estimate the wetting properties of the UBM-coated Si-wafer on one side to the Sn-Pb solder. The wetting curves of the one and both side-coated UBM layers had the similar shape and the parameters characterizing the curve shape showed the similar transition tendency to the temperature. The wetting property estimation was possible with the new wettability indices from the wetting curves of one side-coated specimen; $F_{min}$, $F_{s}t_{s}$ and $t_s$. For UBM of Si-chip, Au/Cu/Cr UBM was better than Au/Ni/Ti in the point of wetting time. The contact angle of the one side coated Si-plate to the Sn-Pb solder could be calculated from the force balance equation by measuring the static state force and the tilt angle.

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Wet to Shrink: an Approach to Realize Negative Expansion upon Wetting

  • Sun, L.;Huang, W.M.
    • Advanced Composite Materials
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    • v.18 no.2
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    • pp.95-103
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    • 2009
  • Composites can be designed to have special properties, and even such properties that are difficult to find in nature. We propose a simple approach to realize negative expansion upon wetting, i.e., contraction upon wetting, using swelling materials. The key parameters in one-dimensional case are investigated, and the possible configurations for two and three-dimensional cases are presented. The feasibility is demonstrated through a simple test.

Experimental investigation on loading collapse curve of unsaturated soils under wetting and drying processes

  • Uchaipichat, Anuchit
    • Geomechanics and Engineering
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    • v.2 no.3
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    • pp.203-211
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    • 2010
  • An experimental program of isotropic loading tests on a compacted kaolin using a conventional triaxial equipment modified for testing unsaturated soils was perform to investigate a loading collapse curve of unsaturated soils along wetting and drying paths. The test data are presented in terms of effective stress on a range of constant suction. The suction hardening behavior was observed for both wetted and dried samples. With the use of an appropriate effective stress parameter, the unique relationship for loading collapse curve for wetting and drying processes was obtained.

The Compressive Strength and Durability Characteristics of Lime-Cement-Soil Mixtures (석회-시멘트 혼합토의 압축강도 및 내구 특성)

  • Oh, Sang-Eun;Yeon, Kyu-Seok;Kim, Ki-Sung;Kim, Yong-Seong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.1
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    • pp.83-91
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    • 2012
  • In this study, the compressive strength characteristics of lime-cement-soil mixtures, composed of lime, soil, and a small amount of cement, were investigated by performing the unconfined compression tests, the freezing and thawing tests, the wetting and drying tests and the permeability tests. The specimens were made by mixing soils with cement and lime. The cement contents were 0, 6, 8 and 10 %, and the lime contents were 2, 4, 5, 10, 15 and 20 % in weight. Each specimen was cured at constant temperature in a humidity room for 3, 7 and 28 days. The compressive strength characteristics of the lime-cement-soil mixtures were then investigated using the unconfined compression tests, freezing and thawing tests and the wetting and drying tests. Based on the test results, a discussion was made on the applicability of the lime-cement-soil mixtures as a construction material.