Preparation of Sn films deposited on carbon nanotubes

In this work carbon nanotubes were first grown on copper substrate by chemical vapor deposition method. The Sn deposits were then deposited on the surface of as-grown carbon nanotubes by three different methods: electroplating, electroless plating and displacing methods. The Sn deposits on CNTs surface were characterized by both scanning electron microscope and field emission scanning electron microscope. The compositions of Sn deposits were analyzed by energy dispersive X-ray spectroscope. The results showed that both electroless plating and displacing deposits can but the electroplating deposits cannot cover on the surface of CNTs. Besides C, Sn, Ni and Pd, the electroless deposits also contain element of oxygen and the displacing deposits also contain elements of copper and oxygen.     

Highly adhesive metal plating on Zylon fiber via iodine pretreatment

Highly adhesive metal plating was performed on poly(p-phenylene-2,6-benzobisoxazole) fiber named Zylon^® via iodine pretreatment followed by electroless plating. First, iodine components were selectively doped into the inner part of the fiber near the surface through iodine vapor exposure. The doped iodine was converted to palladium iodide particles by treating with palladium chloride solution. After the reduction of the iodide to metal palladium particles, electroless copper plating was conducted on the fiber. A uniform copper layer was deposited on the fiber surface and exhibited high durability in durability tests such as ultrasonic exposure, tape peeling-off, and corrosion in NaCl solution. This durability was attributed to the palladium particles formed at the fiber surface that served as an anchor for the plated layer as well as an electroless plating catalyst. The plated fibers also possessed electrical conductivity. Although the tensile strength of the Zylon^® fiber decreased from 5.8 to 4.9 GPa after undergoing the pretreatment and plating processes, the light shielding effect improved the light resistance of the plated fibers in terms of tensile properties. After 18 days of xenon lamp exposure, the plated fibers retained 74% of its initial strength, whereas that of untreated fibers decreased to 43%.     

Selective electroless nickel deposition on copper as a final barrier/bonding layer material for microelectronics applications

A low cost, selective electroless metallisation of integrated circuit (IC) copper bond pads with nickel and gold is demonstrated. This metallurgy can function as a barrier layer/bondable material when deposited as a thin layer or as the chip bump for flip chip applications when deposited to greater heights. Four alternative activation steps for selective electroless nickel deposition on bond pad copper are demonstrated. Selective low cost deposition has been achieved with a proprietary electroless plating bath developed at NMRC and three commercial baths on both sputtered copper substrates and electrolessly deposited copper on titanium nitride barrier layer material.     

Electroless plating of copper on surface-modified glass substrate

This work focuses on developing a novel convenient method for electroless copper deposition on glass material. This method is relied on the formation of amino (NH₂)-terminated film on the surface of glass substrate, by coating polyethylenimine (PEI) on glass matrix and using epichlorohydrin (ECH) as cross-linking agent. The introduced amino groups can effectively adsorb the palladium, the catalysts which could initiate the subsequent Cu electroless plating, onto the glass substrate surface. Finally, a copper film is formed on the palladium-activated glass substrate through copper electroless plating and the surface-coppered glass material is therefore acquired. X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscopy (SEM) images combined with energy diffraction X-ray (EDX) analysis demonstrate the successful copper deposition on the surface of glass substrate.     

Investigation of the structure and the physical properties of nickel-phosphorus ultra-black surfaces

Ultra-black materials with low reflectivity can be applied in many fields of science and technology. We deposited nickel-phosphorus alloys (Ni-P) on copper substrate with the electroless plating method and etched the electroless plating with nitric acid in order to build ultra-black surface. On the one hand, the components of the Ni-P ultra-black surface layer were investigated by XRF and XPS. SEM represented that there are innumerable conical holes with the different diameters on the surface. XRD showed that the whole surface has become amorphous. On the other hand, compared to electroless blackening film by oxidation and black chromium plating materials, the Ni-P ultra-black surface showed lower wavelength dependence and lower reflectance in the range of 380–780 nm. In addition, the temperature of the sample with the Ni-P ultra-black surface increased more highly and quickly compared to the black chromium plating film after exposure in an IR laser for about half an hour. PACS 68.55.-a; 82.80.Kq; 78.68.+m     

Qualitative electroless Ni/Au plating considerations for the solder mask on top of sequential build-up layers

Advanced printed circuit boards (PCBs) with sequential build-up (SBU) layers require alternating dielectric and copper layers on top of a core substrate. This can be achieved by lamination of resin coated copper (RCC) or by coating of dielectric polymers followed by copper deposition. The plating of electroless Ni/Au used as a solderability preservative on top of sequential build-up layers is investigated. For this application a solder mask polymer has to be applied in order to separate solder pads. Experiments showed that on parts of the underlying build-up layer exposed to the electroless Ni plating solution electroless Ni can grow. This overplating is caused by the remains of colloidal Pd/Sn catalyst on top of the build-up layer from preceding electroless Cu deposition. At very small features skipping of the plating can also take place. The overplating and skipping phenomena are influenced by a number of parameters, such as the temperature, the concentration of the stabilizer and pH. The dimensions of features on the board and the thickness of the solder-mask polymer also influence skipping. Based on qualitative analyses of the skipping and overplating phenomena rules of thumb for the solder mask design based on the plating conditions are proposed.     

A plating method for metal coating of fiber Bragg grating

We present a method for metal coating optical fiber and in-fiber Bragg grating. The technology process which is based on electroless plating and electroplating method is described in detail. The fiber is firstly coated with a thin copper or nickel plate with electroless plating method. Then, a thicker nickel plate is coated on the surface of the conductive layer. Under the optimum conditions, the surfaces of chemical plating and electroplating coatings are all smooth and compact. There is no visible defect found in the cross-section. Using this two-step metallization method, the in-fiber Bragg grating can be well protected and its thermal sensitivity can be enhanced. After the metallization process, the fiber sensor is successfully embedded in the 42CrMo steel by brazing method. Thus a smart metal structure is achieved. The embedding results show that the plating method for metallization protection of in-fiber Bragg grating is effective.     

Layer-by-layer growth of MgO thin films controlled by inserting a TiN seed layer using an in-situ pulsed laser deposition

Completely (200)-oriented MgO films were grown on Si(100) with insertion of a TiN seed layer by pulsed laser deposition (PLD). Compared with the conventional direct ablation of a metal Mg or ceramic MgO target, we successfully demonstrated an effective way to improve the crystallinity of MgO thin films. By using TiN as a seed layer, high-quality MgO films with an atomic-scale smooth surface of about 0.55 nm (Ra) were obtained. Moreover, it is found that the quality of MgO films was independent of the thickness of the TiN seed layer. The improved crystalline quality of the MgO films was attributed to the layer-by-layer growth mode during the deposition of MgO films, which was monitored in-situ by reflection high energy electron diffraction (RHEED). PACS 68.55.Jk; 81.15.Fg     

Fabrication of microelectrodes deeply embedded in LiNbO3 using a femtosecond laser

We present a novel technique to fabricate deeply embedded microelectrodes in LiNbO₃ using femtosecond pulsed laser ablation and selective electroless plating. The fabrication process mainly consists of four steps, which are (1) micromachining of microgrooves on the surface of LiNbO₃ by femtosecond laser ablation; (2) formation of AgNO₃ films on substrates; (3) scanning the femtosecond laser beam in the fabricated microgrooves for modification of the inner surfaces; and (4) electroless copper plating. The void-free electroless copper plating is obtained with appropriate cross section of microgrooves and uniform initiation of the autocatalytic deposition on the inner surface of grooves. The dimension and shape of the microelectrodes could be accurately controlled by changing the conditions of femtosecond laser ablation, which in turn can control the distribution of electric field inside LiNbO₃ crystal for various applications, opening up a new approach to fabricate three-dimensional integrated electro-optic devices.     

多弧离子镀工艺对TiN/Ti与Cr/Cu界面及微结构的影响

用多弧离子镀技术在铜基上电镀Cr/Ni层进行不同工艺条件下多弧离子沉积TiN/Ti实验.借助X射线衍射(XRD)和扫描电子显微镜(SEM)研究了TiN/Ti与Cr/Cu接触界面形成、微结构及其组分与形貌.XRD分析显示,薄膜表面组分包含TiN,Ti₂N多晶相外,还包含一些Cr-Ti的金属间化合物等.显然,TiN,Ti₂N在表面上已形成.SEM观察指出,在90℃制备的表面膜具有不平整的类枝状结晶结构.随着温度升高至170℃,得到精细TiN/Ti覆盖层表面,XRD峰 关键词： 多弧离子镀 氮化钛 界面形成 微结构     

Model of electroless Ni deposition on SiCp/Al composites and study of the interfacial interaction of coatings with substrate surface

Metallization techniques based on electroless plating are used to coat SiC_p/Al composite materials. The directly palladium chloride (PdCl₂) solutions in HCl is used to render the surface of such non-conductive substrates catalytically active towards metal deposition in the electroless plating solution. The microstructures of Ni-coated composites provided by scanning electron microscope (SEM) bring light into the palladium activation and electroless coating process. Also, X-ray photoelectron spectroscopy (XPS) and Line-scan have allowed to monitor the chemical and compositional surface modifications of activated and coated SiC_p/Al composites, as well as to understand the mechanisms of the catalyst (palladium species) chemisorption on the composites surface and the interaction mechanisms of Ni layer with the SiC_p/Al composites. The experimental results show that a nickel-substrate bonding action takes place during plating. Ni atom existing on the surface of the composites can partially obtain electrons from metals Al of the SiC_p/Al composites when the substrate is embedded in the Ni layers, that is, the orbital interaction through the mutual overlap of the electronic orbits does exist in the interfacial regions between the coated Ni atoms and composites substrate instead of the mechanical-interlocked form. On the basis of the evidence, a model of electroless Ni deposition on SiC_p/Al composites is submitted including Pd activation and Ni deposition processes to describe the formation of catalytic centers and the growth of deposited layer. The deposition model reveals that metal-substrate bond plays an important role in the high adhesion strength between the Ni coatings and the composites.     

多弧离子镀TiN与不同金属基材间的接触界面与表面特性

用多弧离子镀技术在不同金属基材上进行TiN镀膜实验 ,制备了TiN/Fe、TiN/Cu和TiN/Cr/Cu复合膜 .借助扫描电子显微镜 (SEM)、X射线衍射仪 (XRD)和光电子能谱 (XPS) ,研究了TiN与Fe、Cu和Cr/Cu三种不同衬底接触界面的形貌、结构及其表面特性 .SEM观察发现 ,在一定离子镀膜条件下 ,TiN涂层可与Fe、Cu和Cr/Cu金属基材形成均匀平整的接触界面 ,在铜基上TiN界面清晰 ,在Fe与Cr/Cu界面有明显的层状晶界微结晶分布 .XRD分析显示 ,Fe、Cu和Cr/Cu表面生成的薄膜都包含TiN、Ti2 N等多晶相 ,在Cr/Cu界面还包含Ti-Cr的金属间化合物 .XPS结果表明 ,表面除了TiN膜外 ,还生成TiO2 和TiOxNy 等氧化膜 .Ar+ 刻蚀 5min后 ,TiO2 消失 ,TiOxNy 减少 ,TiN则呈增加趋势 .TiN与Cr/Cu界面形成明显的Ti-Cr和Cr-Ni互扩散层 ,这有助于增强薄膜附着力 ,形成较牢固的TiN涂层 .     

A facile method for preparing highly conductive and reflective surface-silvered polyimide films

A novel method was developed for the preparation of reflective and electrically conductive surface-silvered polyimide (PI) films. The polyimide films were functionalized with poly(dopamine), simply by dipping the PI films into aqueous dopamine solution and mildly stirring at room temperature. Electroless plating of silver was readily carried out on the poly(dopamine) deposited PI (PI-DOPA) surface. The surface compositions of the modified PI films were studied by X-ray photoelectron spectroscopy (XPS). XPS results show that the PI-DOPA surfaces were successfully deposited with ploy(dopamine) and were ready for electroless deposition of silver. The poly(dopamine) layer was used not only as the chemi-sorption sites for silver particles during the electroless plating of silver, but also as an adhesion promotion layer for the electrolessly deposited silver. The as-prepared silvered PI films show high conductivity and reflectivity, with a surface resistance of 1.5 Ω and a reflectivity of 95%, respectively.     

Electroless copper coating of epoxide plates in an ultrasonic field.

This paper reports the study of ultrasonic irradiation effects on electroless copper coating on an epoxide resin. Several parameters were monitored, such as plating rates, practical adhesion and internal stress, versus varying acoustic powers at a constant frequency of 530 kHz. Exposure conditions were characterised by both transmitted power and interfacial mass transfer coefficients. Optimum conditions expressed in irradiation time and power were determined. The use of ultrasound during electroless copper plating affects the plating rates and the deposits properties, particularly the practical adhesion which increases whereas the internal stress decreases. Then, the changes in the coating mechanisms are discussed.     

Mechanism study of femtosecond laser induced selective metallization (FLISM) on glass surfaces

We investigate the mechanism of selective metallization on glass surfaces with the assistance of femtosecond laser irradiation followed by electroless plating. Irradiation of femtosecond laser makes it possible to selectively deposit copper microstructures in the irradiated area on glass surfaces coated with silver nitrate films. The energy-dispersive X-ray (EDX) analyses reveal that silver atoms are produced on the surface of grooves formed by laser ablation, which serve as catalysis seeds for subsequent electroless copper plating.     

Complete filling of 41 nm trench pattern using Cu seed layer deposited by SAM-modified electroless plating and electron-beam evaporation

To overcome the limitation of the sputtered Cu seed layer in electroplating of Cu interconnects imposed by the shadow effect, a new method for depositing a Cu seed layer on a 41 nm trench pattern based on combination of electroless plating (ELP) and electron-beam (E-Beam) evaporation was developed. A Cu seed layer formed by ELP alone was too thin to be used for electroplating due to its high resistivity. To solve this problem, an additional Cu layer was deposited on top of the trench by E-Beam evaporator to enhance the electrical conductivity of the Cu seed layer. The electrical resistivity of the resulting Cu layer was reduced to 4.8 μΩ cm, which was sufficient for the conductive seed layer for electroplating the 41 nm trench pattern. The gap-filling capability also improved and there were no voids or seams in the 41 nm trench pattern. The proposed method can be an effective solution for fabrication of a conductive seed layer to fill a 41 nm trench pattern by electroplating.     

镍-磷/纳米碳管化学复合镀层的研究

采用化学复合镀方法,在基体铜片上进行Ni-P／纳米碳管复合镀．用金相显微镜、扫描电子显微镜、X射线衍射仪和显微硬度计等实验手段研究复合镀层的组织、结构和性能．结果表明:随着镀液中纳米碳管含量的增加,复合镀层表面的颗粒变小且密度增加;复合镀层的硬度随纳米碳管含量的增加而提高;此外,纳米碳管的加入,使镀层由非晶变成了纳米晶,促进了复合镀层的晶化．     

石英光纤的金属镍锡涂敷工艺研究

为了实现石英光纤传感器的无胶金属化封装,需要在光纤表面涂敷金属层。先利用化学镀方法在石英光纤表面镀镍层,再利用电镀工艺电镀锡层,从而获得表面光亮、均匀、附着牢固、可焊性好的金属涂敷层。实验中研究了敏化、活化工艺对镀层的影响并提出一种效果较好的敏化活化方法。给出了石英光纤表面化学镀镍的最佳工艺条件。     

Electroless plating of copper on polyimide films modified by surface-initiated atom-transfer radical polymerization of 4-vinylpyridine

Surface modification of polyimide (PI) films were first carried out by chloromethylation under mild conditions, followed by surface-initiated atom-transfer radical polymerization (ATRP) of 4-vinylpyridine (4VP) from the chloromethylated PI surfaces. The composition and topography of the PI surfaces modified by poly(4-vinylpyridine) (P4VP) were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. The P4VP brushes with well-preserved pyridine groups on the PI surface was used not only as the chemisorption sites for the palladium complexes without prior sensitization by SnCl₂ solution during the electroless plating of copper, but also as an adhesion promotion layer to enhance the adhesion of the electrolessly deposited copper to the PI surfaces. The T-peel adhesion strength of the electrolessly deposited copper on the modified PI surface could reach about 6.6 N/cm. Effects of the polymerization time and the activation time in the PdCl₂ solution on the T-peel adhesion strength of the electrolessly deposited copper in the Sn-free process to the modified PI surface were also studied.     

Effects of ultrasonic irradiation on the properties of coatings obtained by electroless plating and electro plating

This paper deals with the effects of ultrasonic irradiation on electroless copper coating i.e. metallic deposition on non-conductive substrates and on electroplating on metallic substrates. Ultrasonic irradiation was both applied during activation (surface preparation for the electroless coating) and during plating steps in both cases. Several parameters were monitored, such as plating rates, practical adhesion, hardness, internal stress versus varying acoustic powers and frequencies. Optimum conditions for irradiation time, frequency and power were determined for each step. It appears clearly that ultrasound use affects deposit properties. Then, changes in the coating mechanisms can be discussed, and several parameters will be explored in this paper, to explain enhancement of deposit properties: increase in catalyst specific area, stirring dependence, surface energy evolution, dihydrogen desorption, structure of coating.