Regeneration of a Solution for Electroless Copper Plating

The possibility of electrochemical regeneration of a solution for electroless copper plating by membrane electrolysis was studied. The conditions of anodic dissolution of copper in a spent solution for electroless copper plating, under which the concentration of copper ions increases at a rate exceeding by an order of magnitude that of their deposition in the course of electroless copper plating, were examined. A scheme for regeneration of spent solutions for electroless copper plating was suggested.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 586–590.Original Russian Text Copyright © 2005 by Turaev, Kruglikov.     

生物凝胶电镀法制备铜纳米多孔膜

采用生物凝胶电镀法制备铜纳米多孔膜。 电镀电压为5 V,阳极为铜片,实验探究了电镀液成分、电镀时间、阴极衬底及沉积电压对电镀层表面形貌的影响。 采用扫描电子显微镜(SEM)和X射线衍射(XRD)对样品形貌和晶型进行表征,得出制备铜膜的最佳条件。 结果表明,电镀的铜膜颗粒尺寸在100 nm左右,晶粒平均尺寸为25 nm,存在较强的(111)织构,而且XRD结果表明,附着的壳聚糖凝胶对铜膜有保护作用,防止其被氧化。 同时采用电化学工作站对其过程中的电镀电流进行实时测量,电流变化曲线表明电镀进行到一定时间后,电流趋于一个很小的稳定值,壳聚糖凝胶阻止了镀液中铜离子的进一步沉积。     

电位活化现象与金属电沉积初始过程的研究

进行了恒电流电位-时间曲线和循环伏安曲线的测定，显示了铁电极进行氰化物镀铜时，镀层沉积前铁表面的电位活化过程. 对铁电极上焦磷酸盐镀铜的初始过程研究表明，由于铜的析出电位较正，铜是在未活化的电极表面上沉积的，因此镀层的结合强度很差.采用氩离子溅射和X射线光电子能谱相结合的方法，检测焦磷酸盐镀铜层和铁基体界面区含氧量的变化，证明了氧化层的存在. 通过添加辅助络合剂和控制起始电流密度的方法，可以增强无氰电镀时阴极的极化. 当铜的析出电位负于铁基体的活化电位时，可显示出铁表面的电位活化过程，定量测量镀层的结合强度也与氰化物电镀相近.     

陶瓷表面无敏化活化法微细化学镀铜

本文提出一种新的化学镀铜工艺,与激光微细刻蚀技术相结合可在Al2O3基底上实现无敏化活化化学镀铜,获得光亮致密、分辨率较高(40μm),导电性良好的化学镀层.     

基于氯化胆碱离子液体的铜电沉积研究（英文）

采用恒电流和恒电位方法,基于含有氯化铜溶液的乙二醇-氯化胆碱或硫脲-氯化胆碱离子液体,室温下在钢阴极上进行了铜的电沉积. 利用扫描电子显微镜和X-射线衍射技术研究了各种实验条件对电沉积的影响以及沉积层的形貌. 结果表明,室温下施加不超过-0.45 V的沉积电位和不超过-4.0 A·m^-2的沉积电流密度,可以同时从氯化胆碱基乙二醇和硫脲离子液体中沉积得到非常光滑、有光泽、致密且具有良好结合力、色泽鲜艳的铜金属涂层. 铜的电沉积阴极电流效率约为97%.     

Source preparation of actinides and polonium using coins

Electrodeposition is the major method for source preparation of actinides, Pu, Am, Th, U using stainless steel discs and spontaneous deposition for Polonium using discs of silver. Worldwide coins are manufactured of bronze, steel, copper plated steel, cupronickel, brass and alloys of Cu–Ni–Zn. The price of the coins which can be used have a value between 0.1 and 0.4 Euro considerably cheaper than electropolished stainless steel discs, 0.8 Euro. This investigation had the purpose to show the possibility to use coins from different countries for source preparation, the energy resolution and deposition efficiency. We obtained plating recoveries ranging from 50 to 100 % and the energy resolution varied between 21 and 75 keV for the different coins tested.     

Electrochemical deposition of copper on steel from a solution of diacido-1,3-propylenediamine-N,N′-diacetato-N,N′-dipropionate cuprate(II)

The possibility of obtaining smooth homogeneous copper coatings with good adhesion and homogeneous copper coatings with poor adhesion by electrochemical deposition of copper on steel from a solution of nontoxic copper(II) complex with the ligands, 1,3-propylenediamine-N,N′-diacetato-N,N′-di-3-propionic acid, was analyzed. For both types of coatings, the optimum composition of the solution and the optimum deposition conditions were determined.     

Investigation of the mechanism of electroless deposition of copper on functionalized alkanethiolate self-assembled monolayers adsorbed on gold

We have investigated the reaction pathways involved in the unseeded electroless deposition of copper on self-assembled monolayers (SAMs) adsorbed on Au, using time-of-flight secondary ion mass spectrometry, optical microscopy, and scanning electron microscopy. At 22 degrees C copper deposits on both -CH3 and -COOH terminated SAMs. No copper deposition is observed on -OH terminated SAMs because the hydroxyl terminal groups react with formaldehyde in the plating solution, forming an acetal which prevents Cu deposition. At higher deposition temperatures (45 degrees C), no Cu is observed to deposit on -CH3 terminated SAMs because Cu2+ ions are not stabilized on the SAM surface. Copper complexes are still able to form with the -COOH terminal group at 45 degrees C, and so copper continues to be deposited on -COOH terminated SAMs. Copper also penetrates through -CH3 and -COOH terminated SAMs to the Au/S interface, suggesting that soft deposition techniques do not prevent the penetration of low-to-moderate reactivity metals through organic films.     

Interfacial stability of electrodeposition of cuprous oxide films

Experiments on deposition of Cu(2)O films from basic copper sulfate solution show that copper also deposits. At low, but basic values of pH only copper deposits and at high pH only cuprous oxide deposits. In the intermediate range where both compete the system shows oscillations at "constant current." Linear stability analysis has been conducted for such an electrochemical cell to show that oscillations can take place in the parameter space identified in the experiments. The results are keeping with most of the experimental observations, which are many, but not with all. The physical mechanisms behind the oscillations are explained in terms of competing reactions.     

New and clean strategy for the determination of Cu2+ in electroless copper plating baths

This article concerns a new and clean strategy for the determination of Cu(2+) in electroless copper plating baths with differential spectrophotometry. With this strategy, the problem of too high absorbance of Cu(2+) under plating conditions has been solved. We investigated the influence of copper sulfate, sodium hypophosphite, nickel sulfate, sodium citrate, polyglycol, temperature and pH on the absorption spectrum of Cu(2+) in electroless copper plating baths. Five grams per litre of CuSO(4).5H(2)O solution was selected as the reference solution. Experimental results prove that, this strategy has the merits of fast and high accuracy compared to the traditional techniques. Linearly dependent coefficient of the working curve is 0.9999 and the components in the formula have no obvious effect on the detection of Cu(2+) under experimental conditions. Therefore, we can directly move solutions from the EC plating baths for detection, after that the sample can still go back to the baths without any pollution from the plating process to the environment.     

Bottom-up filling in electroless plating with an addition of JGB-RPE

Bottom-up filling of copper for different sub-micrometer trenches was investigated by electroless deposition technique using Janus Green B (JGB) and Triblock copolymers RPE-2520. The bottom-up copper filling usually achieves a relative high deposition rate of copper in the bottom of trenches through inhibiting the surface deposition or accelerating the bottom deposition of copper. The bottom-up filling behavior of electroless copper deposition for different trenches was investigated in a plating bath containing 0.3 mg/L JGB and 1.0 mg/L RPE-2520. The cross-section image with SEM indicated that the trenches with different widths ranging from 110 to 520 nm were completely filled with electroless copper and that no void was found.     

Changes of the Cu electrode real surface area during the process of electroless copper plating

The surface area (nanoscale roughness) of copper coatings deposited from electroless plating solutions containing Quadrol, L(+)- and DL(∓)-tartrate as Cu(II) ion ligands was measured using underpotential deposition thallium monolayer formation. Surface roughness of Cu coatings depends on the plating solution pH and the Cu(II) ligand, and varies over a wide range. In L(+)-tartrate and Quadrol solutions (pH 12.5–13.3) the roughness factor R _f is low and is equal to 2–3 and 4–6, respectively (substrate: electrodeposited Cu; R _f=2.2). Cu coatings of higher surface area are obtained in DL(∓)-tartrate (pH 12.3–12.7) and Quadrol (pH 12.0) solutions: R _f reaches 20–30. The correlation between R _f and Cu deposition rate was found in L(+)-tartrate solution. The Cu surface area changes are discussed in terms of partial electrochemical reactions of the autocatalytic Cu deposition process, and the decisive role of cathodic Cu(II) reduction from adsorbed Cu(II) complex species. Received: 2 November 1999 / Accepted: 22 February 2000     

化学镀技术在超大规模集成电路互连线制造过程的应用

总结自大马士革铜工艺建立以来,电化学工作者利用化学镀技术围绕该工艺而开展的一系列相关研究,介绍了应用化学镀沉积镍三元合金防扩散层和化学镀铜种子层的研究以及离子束沉积法(Ion ized C lus-ter Beam,ICB)形成Pd催化层后的化学镀铜技术和超级化学镀铜方法.简要叙述化学镀铜技术在超大规模集成电路中的应用,总结化学镀铜技术的研究进展,并指出了今后的发展方向.     

印制电路中电镀铜技术研究及应用

电镀铜技术是制造印制电路板、封装载板等电子互连器件的核心技术.本文介绍了印制电路中电镀铜技术及其发展概况,主要总结了电子科技大学印制电路与印制电子团队在印制电路电镀铜技术基础研究和产业化应用等方面的工作.首先,以三次电流分布理论为基础,采用多物理场耦合方法构建阴极表面轮廓线随时间变化的镀层生长过程模型.该模型描述了铜沉...     

5,5-二甲基乙内酰脲在化学镀铜中的作用

在以酒石酸钾钠和乙二胺四乙酸二钠为双配位剂、 甲醛为还原剂的化学镀铜液中, 研究了5,5-二甲基乙内酰脲(DMH)在化学镀铜中的作用. 化学镀铜实验结果表明, DMH提高了镀液的稳定性; 扫描电子显微镜(SEM)结果表明, DMH使镀层颗粒尺寸减小, 镀层光亮致密; 紫外-可见光谱结果表明, DMH在镀液中与Cu(II)不发生强配位作用; 线性伏安扫描结果表明, DMH在化学镀铜过程中能抑制Cu⁺的产生或促进Cu⁺快速还原, 降低甲醛的氧化速率; X射线衍射(XRD)结果表明, 在含和不含DMH化学镀铜液中, 得到的铜镀层均呈现面心立方混晶结构的特征, 且未出现Cu₂O夹杂衍射峰.     

共晶基离子液体的钴电化学沉积

通过恒电流和恒电位方法,研究了不同温度下脲-氯化胆硷（氯仿）基或乙二醇-氯化胆硷（氯仿）基离子液体中氯化钴溶液在铜和钢阴极上的钴电化学沉积行为. 采用扫描电子显微镜和X射线衍射技术,考察了不同试验条件对钴电沉积行为及钴沉积层形貌的影响. 结果表明,当沉积电位达到-0.8 V和沉积电流密度达到-6.0 A·m^-2时,温度范围从30 °C到90 °C,添加0.05 mol·L^-1的五氧化二磷,可以从脲基和乙二醇基离子液体中沉积得到光滑、发亮和良好结合力的金属光泽钴层. 电化学沉积钴的阴极电流效率达到98%.     

化学镀钴和超级化学镀填充的研究进展

随着半导体集成度的不断提高,铜互连线的电阻率迅速提高。当互连线宽度接近7 nm时,铜互连线的电阻率与钴接近。IBM和美国半导体公司（ASE）已经使用金属钴取代铜作为下一代互连线材料。然而,钴种子层的形成和超级电镀钴填充7 nm微孔的技术工艺仍是一个很大的挑战。化学镀是在绝缘体表面形成金属种子层的一种非常简单的方法, 通过超级化学镀填充方式, 直径为几纳米的盲孔可以无空洞和无缝隙的方式完全填充。本文综述了化学镀钴的研究进展,并分析了还原剂种类对化学镀钴沉积速率和镀膜质量的影响。同时, 在长期从事超级化学填充研究的基础上, 作者提出了通过超级化学镀钴技术填充7 nm以及一下微盲孔的钴互连线工艺。     

薄层流动时安法测定电镀废水中的铜

应用薄层流动时安法测定电镀废水中铜的含量 .试样溶液由流动状态转换为静止状态时的时库仑电量与铜离子浓度 (2～ 16mg/L)呈良好的线性关系 .对样品溶液进行 8次平行测定的相对标准偏差小于 0 .1% ,标准加入法测定的回收率为 99%～ 10 3% .该方法克服了电容电流及电极表面性质改变等噪声干扰 ,具有快速灵敏、准确、再现性好的优点     

Electron beam-treated organic monolayers as a negative resist for Cu immersion plating on Si

In the present work, we investigate selective immersion plating of Cu on n-type Si(111) surfaces chemically modified with different organic monolayers and subsequently directly patterned by an electron-beam (e-beam). The organic molecules (1-undecylenic acid, 1-decene and 1-octadecene) were covalently attached to a hydrogen-terminated Si surface. The use of such monolayers as masks for electroless copper deposition by immersion plating on Si surfaces was investigated. Clearly, a masking effect can be observed, the efficiency of which depends on the type of molecule. Further, the effect of e-beam irradiation to improve the masking properties of the organic monolayers was studied. For this, the monolayers were locally irradiated using a scanning electron microscope (SEM) equipped with a lithographic tool. The results show that e-beam-modified organic monolayers can be used as a negative tone resist for copper electroless plating. The selectivity of the Cu deposition at e-beam-untreated regions strongly depends on the applied e-beam dose and on the nature of organic molecules. By optimizing the electroless deposition parameters, homogeneous deposition with complete selectivity can be achieved, leading to high lateral resolution of the Cu patterns.Dedicated to Zbigniew Galus on the occasion of his 70th birthday.