Electroplating Solution Research Articles

Effects of a new combination of additives in electroplating solution on the properties of Cu films in ULSI applications

Effects of a new combination of additives in acid electroplating solution on the properties of Cu thin films have been investigated. The electroplated Cu films exhibit an excellent superfilling behavior. 0.18 μm vias with an aspect ratio exceeding 5 were filled completely without any void or seam. Strong (111) texture was found for the electroplated Cu films. The resistivity of a 450-nm-thick Cu film was measured to be 1.84 μΩ cm.

Nanometer-scale copper electrodeposition from an on-chip source

Using both an on-chip anode as a source of copper and a copper-free, acidic electroplating solution, we have fabricated electrodes with separations on the order of 10 nm or less. During the electrodeposition process, we observe steplike increases in conductance, corresponding to atomic rearrangement. These conductance steps indicate that the separation between the electrodes is on the atomic length scale. Applications of this technique include the fabrication of electrodes with nanometer separations and the repair of both malformed bus lines and damaged masks.

Development of an electroplating solution for codepositing Au–Sn alloys

A relatively stable, weakly acidic, non-cyanide electroplating solution has been developed for deposition of Au–Sn alloys over a range of compositions. The solution consists of Au and Sn chloride salts, as well as ammonium citrate as a buffering agent and sodium sulphite and ascorbic acid as stabilizers. Electrochemical studies have been conducted to examine the effects of the various additives and their concentrations on bath stability and plating behaviour. Preliminary electroplating experiments with the developed solution indicate that uniform, homogeneous deposits can be achieved over a range of compositions, including the technologically important eutectic and near eutectic values.

Integration of Rapid Prototyping and Electroforming for Tooling Application

Solid freeform fabrication integrated with electroforming as a novel process for the generation of metal molds and EDM electrodes is presented in this paper. A part built by stereolithography is metalized by electroless plating and then placed in an electroplating solution where metal is deposited upon the part by electrolysis. After the desired thickness of metal has been reached, the part is removed from the metal shell by heating. The shell is then backed with other materials to form a mold cavity or an EDM electrode. The accuracy of the formed mold cavity or EDM electrode influenced by materials and process parameters is discussed.

アルミニウムアノード酸化／レーザー照射／電気めっきを用いた微細回路板の作製

Fine-pattern coils were fabricated on an insulating board using anodizing, laser irradiation, nickel deposition, insulating board sticking, and aluminum substrate dissolution. Aluminum specimens covered with porous anodic oxide films were irradiated by a pulsed Nd-YAG laser through a beam splitter, iris diaphragm, convex lens, and quartz window in a nickel electroplating solution to remove anodic oxide film. During laser irradiation, the specimen was moved 3-dimensionally with an XYZ stage by a personal computer.The width of the trench produced by film removal increased with increasing laser energy and with decreasing movement speed. After laser irradiation, nickel metal layer was electrodeposited at only the laser irradiated area by cathodic polarization. The specimen stuck on epoxy resin before dissolving the aluminum substrate. Fine pattern coils with nickel lines 15μm wide and at 25μm intervals were made on the insulating board.

Study on Some Properties of the Electrolyte Solution in the Electrodeposition of Palladium

SUMMARYSome properties of Pd electroplating solution were studied. The results showed that current efficiency and velocity of palladium deposition were decreased and increased respectively by raising the current density, which indicated that the stirring of plating solution was an effective route to raise current efficiency. The choice of concentrations of potassium citrate and ammonium oxalate in solution was mainly determined by the complexing ability of potassium citrate for the palladium ion and the solubility of ammonium oxalate. The electrolyte was shown to have a good throwing power and excellent covering power. Hull cell tests showed that an adherent, smooth, bright and white Pd electrodeposit could be obtained.

A Comparison of Liquid and Supercritical Carbon Dioxide as an Extraction Solvent for Plating Bath Treatment

Because of increasing federal regulations, alternative metal recovery methods for spent electroplating baths are needed. Supercritical extraction of waste metals using CO2 is potential candidate for this process. However, because of the high-cost of supercritical fluid processing equipment, an extraction system modeled on the use of liquid CO2 rather than supercritical CO2 may be more economical. For this reason, the use of liquid CO2 containing β-diketones as an extraction solvent for the removal of Ni2+ and Zn2+ from an electroplating solution was investigated and compared to results obtained with supercritical CO2. Acetylacetone (ACAC) and its fluorinated analogues were used as the ligands for the extraction of Ni2+ and Zn2+ from the electroplating bath. While the fluorinated ACAC showed a potential for a higher extraction efficiency, over 70% of both Ni2+ and Zn2+ was extracted using both liquid and supercritical CO2 using a 100-fold molar excess of ACAC. With isopropyl alcohol as a modifier, extraction efficiency was increased to over 80% for both metals using both phases of CO2 as the carrier fluid.

4595474 Electroplating solution recovery system : Ralph Greco assigned to Greco Bros Inc

4595474 Electroplating solution recovery system : Ralph Greco assigned to Greco Bros Inc

Electroplating of Cu xS on CdS

The description of an electroplating solution for which there is no reaction between copper (II) and CdS is given. It contains triethylenetetramine (TRIEN) as masking agent. Despite the lack of reaction, formation of Cu x S ( x < 2) was observed. This is attributed to direct incorporation of Cu(II) from solution, as supported by chemical thermodynamic calculations. As the deposition potential becomes more negative, an increase in the metallic copper present in the formed layer is observed, allowing the compensation of the Cu x S by means of a thermal treatment.

The electrochemical study of a chromium plating bath. I. Reactions leading to solution-free species

The electrode reactions occurring at C, Cr, Cu and Ni cathodes in the standard electroplating solution for chromium, 200 g dm−3 CrO3 and 2 g dm−3 H2SO4, have been reinvestigated. This paper emphasises the study of those reactions which lead to solution-free products; these occur at potentials positive to that necessary for film or metal deposition. For each cathode, theI-E curve shows a wave or peak for the reduction of chromium (VI) to chromium(III) and it is demonstrated that this process is mass transport controlled, apparently by the transport of sulphate ions to the electrode surface. At Cr, Ni and Cu, the potential of the chromium(VI)/chromium(III) couple is determined by the removal of an insulating oxide film which forms spontaneously when the metal is immersed in the bath. In certain conditions it is also possible to define a well formed wave for proton reduction.

The electrochemical study of a chromium plating bath. II. Chromium metal and surface film formation

The investigation of the electrode reactions occurring at metal and vitreous carbon cathodes in the standard chromium electroplating solution, 200 g dm−3 CrO3 and 2 g dm−3 H2SO4, has been continued and this paper considers the mechanism of deposition of metallic chromium and the role of surface films in this process. It is confirmed that chromium deposition occurs at potentials negative to −1.6 V versus Hg/Hg2SO4 and under galvanostatic or potentiostatic conditions, the current efficiency is 30–45%. Moreover at a vitreous carbon electrode, potential step experiments lead to risingI-t transients characteristic of instantaneous nucleation and three dimensional phase growth.

Reversed-phase high-performance liquid chromatography of diethyldithiocarbamate complexes using radial compression columns

The diethyldithiocarbamate complexes of Co(III), Cr(III), Cu(II), Hg(II), Ni(II), Pb(II), Se(IV) and Te(IV) are separable on a Waters Assoc. Radial Pak C 18 column using a mobile phase of methanol-acetonitrile-water (40:35:25), provided the column has been conditioned by prior injection of a concentrated mixture of the complexes. Alternatively, the column can be conditioned by flushing with 0.005 M disodium ethylenediamine tetraacetate (EDTA), with subsequent addition of 1.25ṡ10 -5 M EDTA to the mobile phase. Diethyldithiocarbamate complexes of Pb(II), Cd(II) and Fe(III) gave poor peak shape due to substitution reactions with nickel from stainless steel components of the chromatographic system. The analysis of a synthetic electroplating solution containing salicylsulphonic acid, sulphanilamide and six inorganic ions is illustrated.

Analysis of Gold Foils and Electroplating Solutions for Metallic and Anionic Impurities

A comparison made between an “acid” citrate gold electroplating solution and an alkaline free potassium cyanide‐containing gold electroplating solution demonstrates that both are susceptible to metallic impurity contamination. However, except for silver which is also codeposited from the alkaline electroplating solution, only the acid solution readily releases these impurities to codeposit with the gold. The alkaline solution, on the other hand, immediately becomes contaminated with anionic impurities, such as the formate and carbonate ions, which rapidly build up to a high concentration.

Gas Content of Gold Foils Deposited from Polymer‐Saturated Electroplating Solutions

A study of the reactions of the cyanide ion at the anode of a potassium gold cyanide electroplating solution containing free potassium cyanide has revealed that a brown polymeric material is generated there which not only discolors, but also codeposits with the gold electrodeposit. This polymer is responsible for the gaseous impurities evolved from the gold deposit on subsequent heating. However, electroplating solutions, formulated without the addition of free potassium cyanide, produce gold deposits containing only low levels of gaseous impurities.

メッキ液の汲出量について

メッキ液の汲出量について