• 한국정밀공학회지
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• 제26권7호
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• pp.112-119
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• 2009

The purpose of this study is to evaluate the evaluation of process yield performed by using Sn & Cu treatment on the surface to optimize process condition for Lead-free solder application. The materials which are used for the New Surface Treatment study are Semi-Dulling plating for high speed Sn/Cu alloy of Soft Alloy GTC-33 Pb free known as "UEMURA Method" and plating substrate is alloy 42.Especially in lead-free plating process, it is important to control plating thickness and Copper composition than Sn/Pb plating. Evaluated and controlled plating thickness $12{\pm}3um$, Copper composition $2{\pm}1%$, plating particle and visual inspection. The optimization of these parameters and condition makes it makes possible to apply Sn/Cu Lead-free solder from Sn/Pb alloy.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.481-486
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• 2002

We have investigated the effects of plating materials for Cu lead (Sn-lOPb, AwPdJNi, Sn-3.5Ag, Sn-3Bi and Sn-0.7Cu) on properties of QFP joints using a Sn-8Zn-3Bi solder. The results were compared with the joints using Sn-3. 5Ag-0. 7Cu and Sn-37Pb solders. As a result, the joints with the Sn-3.5Ag, Sn-3Bi and Sn-0.7Cu plated Cu lead had the reliability comparable to those of the Sn-3.5Ag-0.7Cu and Sn-37Pb soldered joints with respect to the joint strength after the high temperature holding tests at 348K to 423k. In particular, the joint with the Sn-3.5Ag plated Cu lead had the best reliability. This is caused by the low growth rate of a Cu-Sn interfacial reaction layer that degrades the joint strength of the soldered joints. Consequently, the Sn-3.5Ag plating was found to be most feasible plating for the Sn-8Zn-3Bi soldered joint.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1337-1342
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• 2008

The whisker grows at the plating of a lead frame so that it causes the serious problem like the short. To prove this case, many people have studied the cause and influence of the tin whisker growth. This study explains the grain size affects the growth of the whisker in the lead frame. By these studies about the whisker, the whisker growth is discovered by stresses generated by the intermetallic compound and CTE mismatch in both plating and base metal. The stresses or lattice defect generated in the plating process changes grain structure of plating. Consequently, these various stresses are stabilized by forming unspecified whiskers through lots of grain boundaries. Because the grain boundary is the path of the whisker growth, the smaller grain size exists, the more whiskers grow.

• 한국표면공학회지
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• 제19권3호
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• pp.92-108
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• 1986

An electroplating on the lead frame fabricated from domestic copper plate was studied experimentally. In this study, nickel was plated on the thin copper lead frame and silver layer was coated on the nickel film in the cyanide electrolyte. The effect of process variables such as current density, plating time, coating thickness and flow rate of electrolytic solution on the properties of coating was investigated. Some samples on each step were fabricated during electroplating. The results obtained from polarization measurement, observation of SEM photograph, adhesion test of coating and microhardness test are as follows. On silver plating, polarization resistance of potentiostatic cathodic polarization curve is reduced as the flow rate of Ag electrolytic solution increases. And above resistance is also reduced when the minor chemicals of sodium cyanide and sodium carbonate are added in potassium silver cyanide bath. The reduced polarization resistance makes silver deposition on the cathode easy. An increase in the current density and the coating thickness causes the particle size of deposit to coarsen, and consequently the Knoop microhardness of the coating decreases. On selective plating an increase in the flow rate of plating solution lead to do high speed plating with high current density. In this case, the surface morphology of deposit is of fine microstructure with high Knoop hardness. An increasing trend of the adhesion of coating was shown with increasing the current density and flow rate of electrolytic solution.

• 한국표면공학회지
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• 제32권3호
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• pp.211-213
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• 1999

In the future, restrictions are likely to be imposed on the use of lead in the electronics industry. In dealing with such a move, we have been developing Pb-free Sn-Ag plating process to replace presently available Sn-Pb process. In this paper, the result of a basic comparison test between Sn-Pb plating and Sn-Ag plating is reported.

• 마이크로전자및패키징학회지
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• 제11권3호
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• pp.1-7
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• 2004

주석 도금은 특정 환경하에서 위스커를 발생시키며, 이는 전자부품의 불량을 초래한다. 최근 세계곳곳에서는 환경보호를 위해 "무연"의 사용을 권고하고 있다. 본 논문에서는 두 종류 무연 도금 재료에서 도금 온도와 신뢰성시험 하에서 성장하는 위스커를 평가하였다. 도금 온도가 높아질수록 표면에 형성되는 도금 입자의 크기는 커지고, 위스커의 성장은 작아진다. 또한 온도 순환시험에서 성장한 위스커는 무광택 Sn 도금은 굽은 모양을, 무광택 Sn-Bi에서는 줄무의 모양이 관찰되었고, Sn 도금에 비해 Sn-Bi에서 위스커가 작게 성장하였다. 무광택 Sn 도금된 FeNi42 리드프레임은 TC 300 사이클에서 직경이 $7.0{\~}10.0{\mu}m$이고, 길이가 $25.0{\~}45.0{\mu}m$인 위스커가 성장하였다. 또한 Cu는 300 사이클에서는 표면에 노듈(핵 상태)만이 관찰되었고, 600 사이클에서 길이가 $3.0{\~}4.0{\mu}m$의 위스커로 성장하였다. TC 600 사이클 후 FeNi42는 계면에서 ${\~}0.34{\mu}m$의 얇은 $Ni_3Sn_4$가, Cu에서는 두께가 $0.76{\~}l.14{\mu}m$인 $Cu_6Sn_5$와 ${\~}0.27{\mu}m$의 $Cu_3Sn$ 화합물들이 두껍게 성장하였다. 따라서 FeNi42 리드프레임은 열팽창계수의 차이, Cu에서는 금속간 화합물의 형성이 위스커의 성장에 영향을 미치는 주요 인자이다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1999년도 추계학술발표회 초록집
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• pp.15-15
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• 1999

In chip plating, several parameters must be taken into consideration. Current density, solution concentration, pH, solution temperature, components volume, chip and media ratio, barrel geometrical shape were most likely found to have an effect to the process yields. The 3 types of barrels utilized in chip plating industry are the conventional rotating barrel. vibrational barrel (vibarrel), and the centrifugal type. Conventional rotating barrel is a close type and is commonly used. The components inside the barrel are circulated by the barrel's rotation at a horizontal axis. Process yield has known to have higher thickness deviation. The vibrational barrel is an open type which offers a wide exposure to electrolyte resulting to a stable thickness deviation. It rotates in a vertical axis coupled with multi-vibration action to facilitate mixed up and easy transportation of components, The centrifugal barrel has its plated work centrifugally compacted against the cathode ring for superior electrical contact with simultaneous rotary motion. This experiment has determined the effect of barrel vibration intensity to the plating thickness distribution. The procedures carried out in the experiment involved the overall plating process., cleaning, rinse, Nickel plating, Tin-Lead plating. Plating time was adjusted to meet the required specification. All other parameters were maintained constant. Two trials were performed to confirm the consistency of the result. The thickness data of the experiment conducted showed that the average mean value obtained from higher vibrational intensity is nearer to the standard mean. The distribution curve shown has a narrower specification limits and it has a reduced variation around the target value, Generally, intensity control in vi-barrel facilitates mixed up and easy transportation of components, However, it is desirable to maintain an optimum vibration intensity to prevent solution intrusion into the chips' internal electrode. A cathodic reaction can occur in the interface of the external and internal electrode. $2HD{\;}+{\;}e{\;}{\rightarrow}20H{\;}+{\;}H_2$ Hydrogen can penetrate into the body and create pressure which can cause cracks. At high intensity, the chip's motion becomes stronger, its contact between each other is delayed and so plating action is being controlled. However, the strong impact created by its collision can damage the external electrode's structure thereby resulting to bad plating condition. 1 lot of chip was divided into two equal partion. Each portion was loaded to the same barrel one after the other. Nickel plating and tin-lead plating was performed in the same station. Portion A maintained the normal barrel vibration intensity and portion B vibration intensity was increased two steps higher. All other parameters, current, solution condition were maintained constant. Generally, plating method find procedures were carried out in a best way to maintained the best plating condition. After plating, samples were taken out from each portion. molded and polished. Plating thickness was investigated for both. To check consistency of results. 2nd trial was done now using different lot of another characteristics.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2003년도 추계학술발표회초록집
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• pp.107-107
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• 2003

• 공업화학
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• 제17권4호
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• pp.343-348
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• 2006

본 연구는 전기분해반응과 이온교환반응이 결합된 하이브리드 공정을 통하여 반도체 부품제조 시 발생하는 도금세정폐수 중에 함유되어 있는 시안을 분해시키고 은, 구리 등의 유가금속은 음극에 석출하고자 하였다. 역세공정 후에도 탈착되지 않은 이온들은 다음과 같은 전해조건으로 강염기성 음이온교환수지로부터 은을 회수하였다. Amberlite IRA 400 (산화전극 1.15 V, 알루미늄전극 1.3 V)과 Amberlite IRA 402 (산화전극 1.10 V, 알루미늄전극 1.2 V)에서의 실험결과 10~30 min 동안에 90~95%의 Ag을 회수할 수 있었다.

• 마이크로전자및패키징학회지
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• 제20권2호
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• pp.29-32
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• 2013

본 연구에서는 LED 리드프레임 상에 Sn-3.5wt%Ag를 무전해도금하여 표면 거칠기와 반사율을 측정하였다. Sn-3.5wt%Ag를 도금하기에 앞서 Sn-3.5wt%Ag 도금층의 반사율을 향상시키기 위하여 Cu 전해도금을 실시하였다. 도금 후 도금액의 교반속도와 온도가 도금층의 표면 거칠기와 반사율에 어떠한 영향을 미치는지 알아보기 위하여 각각의 도금인자에 대해서 표면 거칠기와 반사율을 측정하고자 하였다. 교반속도가 100~300 rpm으로 증가함에 따라 표면 거칠기는 0.513 ${\mu}m$에서 0.266 ${\mu}m$으로 감소하였으며, 반사율은 1.67 GAM에서 1.86 GAM으로 증가하였다. 또한 온도가 $25{\sim}45^{\circ}C$로 증가함에 따라 표면 거칠기는 0.507 ${\mu}m$에서 0.350 ${\mu}m$으로 감소하였으며, 반사율은 1.68 GAM에서 1.84 GAM으로 증가하였다.