Copper Surface Treatment Research Articles

Copper Surface Treatment with deep UV Ultrafast Laser for Improved Photocathode Photoemissive Properties

Cesium Telluride (Cs2Te) constitutes today the photoemissive semiconductor material of choice for electron accelerators due to its high quantum efficiency (QE) in the deep ultraviolet (DUV) spectral range, and capability to produce high charge over a long operation lifetime. Unfortunately, its chemical instability requires ultra-high vacuum (in the 10-10 mbar range). This inevitably complicates Cs2Te photocathode handling, and increases the overall cost compared to metallic counterparts. Copper photocathodes are alternative candidates, and although they are much more tolerant in terms of vacuum requirements, their use in high average current photo-injectors is limited due to their orders of magnitude lower QE (around 10-5 per unit). With the development of nanophotonics, plasmonic phenomena can now be exploited to tailor a new range of effects in the photoemission process. In this work, we focus on direct laser fabrication of nanostructures for plasmonic electric-field enhancement on copper, and study their potential for enhancing the quantum yield. We develop a methodology to fabricate the nanostructures by irradiating the Cu surface with 257 nm femtosecond pulses, well above copper’s work function. We directly obtained nanostructures 100-200 nm, matching the plasmonic resonance for photoinjector wavelengths. The study is accompanied by a parametric scan allowing to obtain the optimal laser machining parameters, and the analysis of the nanostructure morphologies obtained.

Copper Surface Treatment Method with Antibacterial Performance Using "Super-Spread Wetting" Properties.

In this work, a copper coating is developed on a carbon steel substrate by exploiting the superwetting properties of liquid copper. We characterize the surface morphology, chemical composition, roughness, wettability, ability to release a copper ion from surfaces, and antibacterial efficacy (against Escherichia coli and Staphylococcus aureus). The coating shows a dense microstructure and good adhesion, with thicknesses of approximately 20–40 µm. X-ray diffraction (XRD) analysis reveals that the coated surface structure is composed of Cu, Cu2O, and CuO. The surface roughness and contact angle measurements suggest that the copper coating is rougher and more hydrophobic than the substrate. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) measurements reveal a dissolution of copper ions in chloride-containing environments. The antibacterial test shows that the copper coating achieves a 99.99% reduction of E. coli and S. aureus. This study suggests that the characteristics of the copper-coated surface, including the chemical composition, high surface roughness, good wettability, and ability for copper ion release, may result in surfaces with antibacterial properties.

Copper Surface Treatment in Metal-Polymer Direct Molding Technology

Copper Surface Treatment in Metal-Polymer Direct Molding Technology

Evaluation of Copper Alloy Surfaces for Inactivation of Tulane Virus and Human Noroviruses

This study evaluated the efficacy of copper alloy surfaces for inactivation of Tulane virus (TV), assessed by plaque assay and porcine gastric mucin-conjugated magnetic bead (PGM-MB) binding assay, followed by quantitative reverse transcription PCR (PGM-MB-RT-qPCR assay). In addition, the efficacy of a copper surface for inactivation of human norovirus (HuNoV) GII.4 Sydney and GI.3B Potsdam strains was evaluated by PGM-MB-RT-qPCR assay. Results of time-dependent inactivation of viruses on copper, bronze, and brass coupons revealed that 15 min of surface treatments of each of the copper and copper alloys achieved >4-log reduction of purified TV, as assessed by plaque assay, while up to 20 min of copper alloy surface treatments only achieved ∼2-log reduction, as assessed by PGM-MB-RT-qPCR assay. As assessed by PGM-MB-RT-qPCR assay, 10 min of copper surface treatments achieved reductions of 3 and 4 log units for HuNoVs GII.4 Sydney and GI.3B Potsdam, respectively. Results from this study suggest that even though PGM-MB-RT-qPCR assay underestimated the efficacy of copper alloy surface inactivation of TV, copper alloy surfaces were able to effectively inactivate TV and HuNoVs. Therefore, copper alloys can be used as a preventive measure to prevent HuNoV infection and are an effective surface treatment for HuNoVs.

Surface treatment of copper (II) oxide nanoparticles using citric acid and ascorbic acid as biocompatible molecules and their utilization for the preparation of poly(vinyl chloride) novel nanocomposite films

In the present study, solution casting method was used for the preparation of nanocomposite films. Primarily, the surface of copper (II) oxide (CuO) nanoparticles was modified with biosafe molecules such as citric acid and ascorbic acid for better dispersion in the polymer matrix. Then novel nanocomposite films were fabricated by loading various percentages of modified CuO nanoparticles in the poly(vinyl chloride) matrix. The ultraviolet (UV)-blocking effects of nanocomposites and their optical properties were studied using UV-visible spectroscopy. Also, other analyses, including Fourier transform infrared spectroscopy, mechanical tensile test, thermogravimetric analysis, and X-microscopy, were performed for investigating thermal, mechanical, and morphological properties of the hybrid materials.

Comparative study of copper surface treatment with self-assembled monolayers of aliphatic thiol, dithiol and dithiocarboxylic acid

The stability of alkanethiol self-assembled monolayers (SAMs) on metallic substrates, in particular copper, is an important aspect for their application. Some technologies, such as lithographic patterning, can potentially benefit from the use of a transient easily removal protective coatings. Other applications like corrosion resistance, and thin-film lubrication request rather robust and stable films. The aim of this work consists in a comparative investigation of three organothiols ( n-tetradecanethiol or RSH, 2-dodecylpropane-1,3-dithiol or R(SH) 2 and n-tetradecanedithiocarboxylic or RS 2H) on their ability to form SAMs on electrochemically reduced polycrystalline copper substrates and their respective stability. Characterizations of the SAMs are carried out using contact angle goniometry, XPS, PM-IRRAS and electrochemical studies (CV, LSV and cathodic desorption). R(SH) 2 leads to monolayers with lower molecular organization than in the case of RSH and RS 2H molecules. R(SH) 2 monolayers are found the more stable when subjected to both anodic and cathodic desorption tests.

Structural performance of the glass fiber–vinyl ester composites with interlaminar copper inserts

Mechanical performance in tension, compression and flexure of glass fiber reinforced vinyl ester composites with interlaminar copper inserts was evaluated experimentally. Key variables in performance evaluation were relative size of the copper insert and surface treatment of copper. Test coupons were manufactured using VARTM method and tested following ASTM standards for tension, compression and flexure (four-point bend). Process-induced residual strains were measured during fabrication and proved to have minimal impact for the specific thermal cycles involved. Mechanical test results indicate that the change in insert size or surface treatment have minimal impact on tensile properties though the presence of copper inserts increases failure strain. Both insert size and surface treatment have a strong impact on compression and flexural properties associated with compression mode. Decrease in mechanical properties under compression and flexure are mainly due to poor adhesion between the copper surface and the composite and the resulting delaminations. For composites with large inserts, compatible surface treatments restored both compression and flexure properties to the equivalent baseline (no copper insert) performance.

Shear Strengths of Copper/Insulation Interfaces After In-Core Reactor Irradiations

The adhesive shear strengths of copper/insulation interfaces were evaluated using a novel specimen design in which thin copper foils were embedded in laminate structures. In each instance, the copper surface was either chemically or physically treated prior to laminate fabrication. Once produced, the specimens were subjected to in-core reactor irradiations providing total radiation doses of 10, 22, and 100 MGy with a gamma/neutron ratio representative of conditions in fusion systems. Post-irradiation short-beam-shear tests indicate that the best-performing copper treatments retain 65-70% of their original interfacial shear strength at 76 K after receiving a total dose of 100 MGy. Previous findings showed that the initial adhesive strength could be improved through the use of copper surface treatments, and these results confirm that the copper/insulation interface remains strong after exposure to high-radiation environments.

低誘電率樹脂埋め込みされたスーパーコネクトレベル配線の要素技術に対する電気的信頼性の評価

We have fabricated a refined copper wiring pattern with a super-connect level on insulating low-k resin, and embedded it in the same insulating resin. We made it by means of a semi-additive process, which enables a flat connection between the copper pattern and the insulating resin. The surface of the copper pattern was processed with a black-oxide treatment (adhesion-promoting copper surface treatment) . The sample was prepared both with and without “A” treatment. The aim of“A”treatment is improvement of the bonding strength between the resins. This paper aims to evaluate the ionic migration durability of the newly developed sample under high temperature and high humidity conditions. We investigated the influence of the treatment that fosters ionic migration, and adopted a mainly AC-impedance method for the analysis of the ionic migration. The impedance analysis gave the initial information for the ionic migration. This analysis method could be used for the estimation of forthcoming ionic migrations.

Nd:YAG laser surface treatment of copper to improve the wettability of Sn3.5Ag solder on copper

Nd:YAG laser surface treatment of copper was found to affect the wettability characteristics of SnAg eutectic lead-free solder on copper. The basic process phenomenon was investigated and the microstructure and wetting characteristics of the solder was determined using optical microscopy and X-ray diffraction techniques. To analyze mechanism of the microstructure changes in the surface layer after laser treatment, a finite element modeling (FEM) model was proposed, the simulated temperature distribution and temperature gradient distribution in the surface layer were presented. The results showed that laser surface treatment can improve the wetting characteristics of the Sn3.5Ag solder on the copper and the mechanism was discussed in detail. The work has shown clearly that laser irradiation can be used to improve the wettability of Sn3.5Ag solder on copper.

Rate control for copper tarnishing

The reduction of copper sulphide and copper oxides originated during artificial tarnishing of copper is studied using potentiodynamic potential/current density experiments. Six copper surface treatments are considered: mechanical polishing; indoor exposure for 7 days; chemical etching in 1.6 M nitric acid; chemical etching and heating at 160 °C; and chemical etching and dipping in a 9 × 10 −4 M or 0.9 M potassium sulphide (K 2S) solution at 70 °C. Cuprite (Cu 2O) and chalcocite (Cu 2S) are the main compounds formed. A linear relationship with the square root of the scan rate ( ν) is obtained by plotting the potentiodynamic potential/current density for the tarnish dissolution processes. A relationship between potential and current density cathodic peaks is not obtained, according to Müller’s model, showing a proportionality factor with the dimensions of a resistance.

The relationship between self‐annealing of plated copper and copper surface treatment

This paper discusses how the grain size of plated copper changes as time passes by observing the copper surface topography after surface treatment with a roughening agent. This paper also discusses how the time until the recrystallization terminates depends on the amount and type of plating additives as well as current density. The results agree with the known mechanism of grain growth. As a result of our experiments, the best process to gain the optimal surface topography is proposed. We firmly believe that this paper will contribute to the improvement in quality control of the copper surface treatment process, which will in turn lead to the fabrication of PCBs and plastic packages with higher reliability.

Surface treatment of copper

This study explores the contribution of phonotactic regularities to the way we measure morphological similarity between words. I focus on how morphological similarity fits with conventional morphemic analysis and present a method to exploit the latter to create two reference resources from the English part of the CELEX database. The resources are used for the comparison and evaluation of morphological similarity metrics. I also compare four measures that estimate morphological similarity: the standard edition distance of Levenshtein; the measure of De Pauw and Wagacha; Proxinette; and PHACTS. The study provides an idea of the contribution of phonotactic regularities to morphological similarity.

多層プリント配線板用内層銅箔処理

多層プリント配線板用内層銅箔処理

Laser surface treatment of copper

Copper specimens were irradiated with a KrF excimer laser. The surface morphology and structure of laser-treated copper was examined using optical and electron microscopy. Using X-ray diffraction, the residual stress on the copper surface layers was found to change from tensile to compressive as a result of laser treatment. The surface roughness of the copper was observed to be a function of laser power density. The corrosion resistance of the laser-treated copper was also studied in an NaCl solution.

Adhesion Test for Dry Film Photoresist on Copper by the Peeling Method

This study describes a peel test to quantitatively measure the adhesion of dry film photoresist on copper. Using this peeling method, the adhesion effects of: (a) the copper surface treatments, (b) the UV radiation of a laminated resist, and (c) the baking of a resist laminated coupon were measured. Adhesive tape with rectangular or wedge‐shaped openings was placed between the photoresist and copper surfaces with the adhesive side facing the resist. The openings in the tape allowed for contact between the copper surface and the resist, and the opening dimensions determined the width and length of contact. With the aid of the adhesive tape, a better grip of the resist was obtained during the peeling. The results of this study led to the following conclusions: A tin‐silane (SNS) treated copper surface with a peeling strength of 4–7 lbs/in. was the most effective surface treatment. A UV radiation dose below or equal to 32 mJ/cm2 produces an adhesion of the resist with micro‐etched copper of 38±03 lbs/in; above this dose, adhesion increases. Thermal baking improves adhesion; the calculated activation energy of a micro‐etched copper surface with the resist is 65 kcal/mole.

New Copper Surface Treatment for Polyimide Multilayer Printed Wiring Boards

A new treatment method for the copper innerlayers of polyimide multilayer printed wiring boards has been developed. Conventional oxide coatings experience acid penetration through the bonding interface during through‐hole plating pretreatment. This problem was eliminated by substitution of metallic copper for the surface oxide. Promotion of the copper innerlayer adhesion to the prepreg by the oxide coating was based upon a mechanical interlocking effect caused by the minute roughness of the oxide crystals. Reduction treatment of the surface oxide layer was found to give a metallic copper surface with no changes in its morphology. Adhesion strength of polyimide prepregs to copper foils after the reduction treatment was equivalent to that of the original brown oxide coating. Acid resistance was enhanced by elimination of the oxide layer from the bonding interface. The reduction treatment, combined with the conventional oxide coating technique, can realise high density multilayer printed wiring boards with greater reliability and performance.

Modification of the electrochemical behavior of copper by azole compounds

Cyclic voltammetry and chrnonocoulometry have been employed to study the anodic oxidation of copper in acetate-buffered media, and the effect of pretreatment of the copper surface by immersion in azole solutions on the anodic reactions was obeserved. Azole compounds have been shown to react with metallic copper to form surface films which in some cases provide protection against corrosion. The effects of benzotriazole, (BTA), imidazole (IMIDA) and benzimidazole (BIMIDA), all of which have been considered or used for the inhibition of undesirable surface reactions on copper, have been compared. Pretreatment of copper by immersion in azole solutions results in the inhibition of the anodic oxidation reactions of copper. More pronounced effects are obeserved for in situ studies, in which experiments are carried out as the copper electrode sits in the azole solution of interest. The degree on inhibition of anodic oxidation reactions produced by azole pretreatment decreases in order BTA > BIMIDA ≅ IMIDA. Investigations carried out at different pH values and different inhibitor concentrations may be useful in determining the optimum conditions for copper surface treatments. Electrochemical techniques may be used as a basis for comparing treated and untreated copper surfaces.

Surface Treatments and Bondability of Copper Thick Film Circuits

Crucial issues in using copper thick film microcircuits, namely, surface treatment and bondability, are addressed. A multilayer multichip ceramic substrate package with copper thick film conductors was used for these experiments. Surface treatments for bondability specific to different types of bonding sites are discussed. Using a flip tape automated bonding (TAB) technology, the resultant bond interfaces were analyzed in the as-bonded as well as thermally aged conditions. Results indicate a metallurgically stable materials system which should exhibit long-term reliability. Specific recommendations on copper surface treatments and general guidelines on materials selection are made on the production of reliable copper thick film interconnections.

Studies on adhesion of allylic resin. I. Adhesion of diallylphthalate resin and dichromate‐treated copper foil

AbstractAn effective copper surface treatment for adhesive bonding of copper foil and diallylphthalate resin was investigated.It involves dipping the copper foil in the potassium dichromate‐sulfuric acid solution (K2Cr2O7:76 g/l, H2SO4:0.67 N) at 60°C for 5 min. The dichromate treated copper foil and glass based prepregs of diallylphthalate resin were laminated under the pressure of 38 kg/cm2 for 30 min at 145°C.Interface characteristics of the dichromate treated copper foil and diallylphthalate resin were examined.It was found that chromium is formed on the surfaces of the treated copper foil, and allyl groups in diallylphthalate molecule are oriented to the atoms, that is, the adhesive bonding is performed by the chemical affinity of chromium and allyl groups.The allyl group has a delocalized π‐electron system, and that its bonding to a transition metal as chromium is appropriate and justifiable by quantum chemical considerations.