Showing papers on "Copper plating published in 2003"

Inhibition due to the interaction of polyethylene glycol, chloride, and copper in plating baths: A surface-enhanced Raman study

Abstract: The synergic effect of poly(ethylene glycol) together with chloride ion for inhibiting copper deposition in copper electroplating has been of particular interest for some time. In this study, the potential-dependent behavior of poly(ethylene glycol), with or without chloride ion in a copper electroplating bath is investigated using the surface-enhanced Raman spectroscopy technique. The presence of chloride proves to play a significant role in enhancing PEG adsorption to the Cu electrode surface. More importantly, spectroscopic evidence strongly suggests the formation of a PEG−Cu−Cl complex. By comparing experiment with vibrational modes calculated by using the Hartree−Fock method with a 3-21G* basis set, the structure of this complex is proposed to be a three-coordinated Cu center with two oxygen atoms from PEG and one chloride ligand.

Method to achieve continuous hydrogen saturation in sparingly used electroless nickel plating process

Abstract: An improved wire bonding process for copper-metallized integrated circuits is provided by a nickel layer that acts as a barrier against up-diffusing copper. In accordance with the present invention the nickel bath is placed and remains in hydrogen saturation by providing a piece of metal that remains in the nickel plating tank before and during the plating process.

Additive Behavior during Copper Electrodeposition in Solutions Containing Cl - , PEG, and SPS

Abstract: This paper documents an experimental investigation of additive behavior in acidic copper plating solutions containing chloride ions, polyethylene glycol (PEG), and bis-(3-sodiumsulfopropyl disulfide) (SPS). These solutions represent a simplified model of solutions used industrially for electroplating copper interconnects. Experiments were conducted with use of a rotating disk electrode under both galvanostatic and potentiostatic conditions and the transient behavior was observed. Linear sweep voltammetry was also performed. A transition time for the system to reach steady state was observed under both galvanostatic and potentiostatic conditions and found to be a strong function of SPS concentration. Superfilling is made possible by the existence of a long transition time that permits establishment of a significant rate difference between the top and bottom of the cavity. Experimental results provide evidence for slow adsorption and desorption of the accelerator and SPS incorporation into the deposit. Linear sweep voltammetry indicates that behavior of the accelerator is potential dependent. The same mechanism used to explain superfilling can be applied to explain the leveling/brightening of copper surfaces in these solutions.

Method for forming copper bump antioxidation surface

Abstract: A method for forming a copper bump for flip chip bonding having improved oxidation resistance and thermal stability including providing a copper column having a thickness of at least about 40 microns overlying a metallurgy including an uppermost copper metal layer and a lowermost titanium layer the lowermost titanium layer in contact with an exposed copper bonding pad portion surrounded by a passivation layer; and, selectively depositing at least one protective metal layer over the copper column according to an electrolytic deposition process.

Printed circuit board with embedded capacitors therein, and process for manufacturing the same

Abstract: Disclosed herein are a printed circuit board with embedded capacitors therein and a process for manufacturing the printed circuit board. The embedded capacitors are formed by applying a photosensitive insulating resin to a printed circuit board inner layer, and applying a high dielectric polymer capacitor paste thereto. The process for manufacturing a printed circuit board with embedded capacitors therein comprises the steps of: i) laminating photoresist dry films to a copper clad FR-4, exposing to light and developing the dry films, and etching copper foils of the copper clad FR-4 to form bottom electrodes for forming capacitors; ii) applying a photosensitive insulating resin to the surfaces of the bottom electrodes, and exposing to light and developing to etch the photosensitive insulating resin; iii) applying a capacitor paste to the etched regions and curing the capacitor paste; iv) plating the upper regions of the cured capacitor paste and the photosensitive insulating resin using an electroless copper plating process to form copper foil layers for top electrodes; v) laminating photosensitive dry films to the copper foil layers for top electrodes, and exposing to light and developing the photosensitive dry films to etch regions of the dry films except for the copper foil layers where the top electrodes are to be formed; and vi) etching the regions of the dry films except for the copper foil layers where the top electrodes are to be formed, and the dry films formed on the top electrodes are removed so that the capacitor paste is discretely positioned between the top electrodes and the bottom electrodes to form discrete capacitors.

Interactions Between Brightener and Chloride Ions on Copper Electroplating for Laser-Drilled Via-Hole Filling

Abstract: Blind vias with hole sizes of 85 and 110 μm formed by laser ablation on printed circuit boards were employed for investigation of filling by copper electroplating. The plating solution formulated was composed of acid copper sulfate, polyethylene glycol, 3-mercapto-1-propanesulfonate (MPS). and chloride ions. A "bottom-up" filling behavior had been observed with an appropriate MPS concentration. When MPS concentration was higher than 5.6 X 10 - 6 mol/L, conformal deposition occurred. However, this situation could be altered by adding more chloride ions into the plating solution to recover the behavior of bottom-up filling. Scanning electron microscopy showed that the recovely of bottom-up filling behavior is due to CuCl crystals formed by a synergistic effect between NIPS and chloride ions. The synergistic effect results in acceleration of copper growth in via holes. These experimental results agree with the curvature-enhanced accelerator coverage mechanism.

Advanced copper electroplating for application of electronics

Abstract: Copper electroplating has been of much interest for the interconnection of printed circuit boards (PCBs) and ultra large scale integration (ULSI), wiring so-called damascene process. Therefore, copper filling by electroplating has been actively studied. In this research, via-filling for build-up process of PCBs and the ULSI wiring formation without void and overplate has been examined using an acid cupric sulfate bath containing chloride (Cl), polyethylene glycol, bis (3-sulfopropyl) disulfidedisodium, Janus Green B and thiourea. The void-free filling in the range of 0.18–180 μm width via holes and trenches can be achieved by the selection of these additives. It is confirmed that the elements of these additives are detected only on the upper layer part of copper films by glow discharge optical emission spectroscopy.

The Decomposition of the Sulfonate Additive Sulfopropyl Sulfonate in Acid Copper Electroplating Chemistries

Abstract: The decomposition of sulfopropyl sulfonate ~SPS, 4,5-dithiaoctane-1,8-disulfonic acid! in acid copper electroplating chemistries was studied using scanning electrochemical microscopy ~SECM!, UV-visible spectroscopy, high pressure liquid chromatography, liquid chromatography mass spectrometry, and electron spin resonance. The primary decomposition product is proposed to be the thiolsulfonate of SPS. Although this oxidation product can be formed by reaction with hydrogen peroxide, SECM studies of oxygen reduction on copper showed that there is not a peroxide intermediate and the product of oxygen reduction on copper in dilute sulfuric acid is water. The data suggests that SPS stabilizes Cu ~I! and this complex is the intermediate. For this scheme, oxygen reacts with the SPS/Cu~I! complex in solution to form the thiolsulfonate of SPS and Cu~II!.

Effects of deposition modes on the microstructure of copper deposits from an acidic sulfate bath

Abstract: The electrodeposition of various copper deposits was carried out by means of cyclic voltammetric, potentiostatic, galvanostatic, pulse-rest and pulse-reverse plating modes in a simple acidic CuSO4 bath without any additives, although the 8 mM CuSO4 solution employed in this work was not practically applicable for electroplating. The morphologies of these Cu deposits were systematically compared by atomic force microscopy (AFM), and scanning electron microscopy (SEM). The average grain size and roughness of Cu deposits were found to strongly depend on the deposition modes. From the results of SEM and AFM, the Cu deposit plated by cyclic voltammetry showed the smoothest and most compact morphology with the smallest average grain size. When the deposition potentials were negative to −0.17 V, nucleation of Cu seeds and growth of Cu grains occurred simultaneously, resulting in the presence of relatively small Cu clusters on the deposit grains. The anodic process through means of either cyclic voltammetry or reverse plating rendered the significant dissolution of grain peaks and these small Cu clusters on the deposit, resulting in a relatively smooth surface.

Direct Copper Electrodeposition on TaN Barrier Layers

Abstract: In current copper metallization technology, 1-3 copper is electrodeposited onto a barrier layer precovered by a thin copper seed layer deposited using physical vapor deposition ~PVD! or chemical vapor deposition ~CVD! techniques. As the feature sizes of trenches and vias continue to shrink, the ability to deposit a continuous and defect-free seed layer is becoming increasingly difficult. Furthermore, with feature sizes decreasing below 100 nm, the seed layer will become a significant fraction of the metallization. As a result, strategies for the direct deposition of copper onto the barrier layer are being explored. In this paper, we report on electrodeposition of copper onto TaN barrier layers from the sulfate, fluoroborate, ethylenediaminetetraacetate ~EDTA!, and citrate solutions. These solutions include complexing and noncomplexing agents and span a wide range of pH values. Copper sulfate solutions ~Ref. 4-12 and references therein! are currently used in copper metallization technology. These solutions usually contain additives such as polyethylene glycol ~PEG! and chloride ions, which co-adsorb on the copper surface and decrease the rate of deposition. 11,12 The addition of additives such as bis~3-sulfopropyl! disulfide ~SPS! results in enhanced deposition rates at the bottom of features such as trenches or vias, leading to void- free deposits. 3 Copper deposition from sulfate solutions on copper seed layers has been studied in detail, and a number of models for deposition into patterned structures have been reported in the literature. 4-10

Accelerator aging effects during copper electrodeposition

Abstract: Slow sweep rate voltammetric analysis of the Cu/Cu~II! deposition reaction is shown to be an effective tool for examining aging effects associated with thiol and disulfide additives that are widely employed as brighteners. Sulfonate-terminated short chain thiols are spontaneously oxidized by Cu~II! to form disulfide molecules with the conversion being complete within a few hours of electrolyte preparation. An additional aging effect occurs during electrolysis in conventional unseparated electrochemical cells. At the anode, the disulfide is reduced by Cu~I! forming thiolate complexes which subsequently affect the copper deposition reaction occurring at the cathode. The latter effect may be avoided by using a cation selective membrane to isolate the anode compartment. The application of electrodeposition in state of the art manufacturing of microelectronic devices together with advances in analytical methods has revitalized scientific investigations into the role of organic additives in electroplating. Of particular interest is the combined use of rate accelerating and inhibiting species for copper ‘‘superfilling,’’ or ‘‘bottom-up’’ filling, of submicrometer features in dual damascene processing. 1 Sulfonate-terminated alkanethiols or disulfides are representative of a class of accelerators which are usually present at micromolar concentrations in bright plating baths. 2,3 These species adsorb on the copper surface as either thiolates or disulfides and, when combined with a sulfonate end group, disrupt the inhibiting function of the polyether-halide-Cu ~I! layer. 3,4 The superconformal growth mode that arises from this competition is well described by the curvature enhanced accelerator coverage mechanism ~CEAC! whereby surface area decrease of an advancing surface of concave curvature results in enrichment of the more strongly bound surface species. 5-10 In the thiol/disulfide-polyetherhalide system, it is the accelerating thiol or disulfide species that are more strongly chemisorbed; they thus become concentrated during deposition on concave surfaces of trenches and vias leading to bottom-up filling. The overriding importance of this geometrical effect in superfilling was recently demonstrated by first derivitizing a patterned electrode with submonolayer quantities of thiolate or disulfide followed by electrodeposition of copper from an electrolyte containing only the polyether-halide inhibitor precursors as additives. 11 Feature filling proceeded in a manner analogous to that observed when the thiol or disulfide were present in the copper plating solution. This indicates that homogeneous thiol/disulfide chemistry has little to do with the superconformal feature filling process per se. Nevertheless, evidence of accelerator aging effects associated with homogeneous chemistry, beyond simple consumption, have been widely noted with an emphasis on the interactions occurring between copper, Cu~I! ,C u~II!, thiol/disulfide, oxygen, and related products. 12-15 From a practical perspective these reactions appear to significantly hamper process control. 12-15 A previous study of the instability of thiols and disulfides in copper plating indicates that Cu~II! slowly oxidizes thiols while Cu~I! stimulates the decomposition of disulfides. 12 The report was based on examination of the oxidation behavior of these compounds at glassy carbon electrodes in combination with colorimetric studies which were generally performed in electrolytes containing high accelerator concentrations ~up to 1 mmol/L!. 12 The high concentrations were used to provide a strong analytical signal although plating operations usually employ accelerator concentrations in the 5 mmol/L range. It was anticipated that the effect of concentration might be simply reflected in the kinetics of the stated decomposition reactions. From a technological perspective, aging effects are usually dealt with by using a ‘‘bleed and feed’’ scheme whereby new additives are continually added to the electrolyte while used electrolyte is drained to maintain the cell volume. In this paper, the sensitivity of the kinetics of the copper deposition reaction to accelerator chemistry will be exploited in order to examine accelerator aging under conditions directly relevant to the superfilling process. It is shown that these effects can be understood in terms of conversion between disulfides and thiols and vice-versa. Furthermore, it is demonstrated that significant improvements in process stability can be obtained by using a cation selective membrane to separate the anode and cathode compartments. Experimental Slow sweep cyclic voltammetry was used to examine the aging effects associated with thiol and disulfide-based accelerators. For all the experiments described herein, the base electrolyte was 0.24

Copper electroplating technology for microvia filling

Abstract: This paper describes a copper electroplating enabling technology for filling microvias. Driven by the need for faster, smaller and higher performance communication and electronic devices, sequential build up (SBU) technology has been adopted as a viable multilayer printed circuit manufacturing technology. Increased wiring density, reduced line widths, smaller through‐holes and microvias are all attributes of these high density interconnect (HDI) packages. Filling the microvias with conductive material allows the use of stacked vias and via in pad designs. Other potential design attributes include thermal management enhancement and benefits for high frequency circuitry. Electrodeposited copper can be utilized for filling microvias and provides potential advantages over alternative via plugging techniques. The features, development, scale up and results of direct current (DC) and periodic pulse reverse (PPR) acid copper via filling processes, including chemistry and equipment, are described.

Electronic component package and its manufacturing method

Abstract: PROBLEM TO BE SOLVED: To provide an electronic component package and its manufacturing method for realizing a shield effect sufficient for miniaturizing an electronic apparatus, reducing its height, reducing its weight and increasing frequency, according to the improvement in the sealing properties of the electronic component package. SOLUTION: The electronic component package is composed of a circuit board 1 having a ground pattern 3, a packaging component 5 composed of an electronic component packaged on an upper surface of the circuit board 1, a seal 6 composed of epoxy resin containing an inorganic filler for sealing the packaging component 5, and a shielding layer, composed of an electroless copper plating layer as a first layer 7 to be formed on the surface of the seal 6, an electrolytic copper plating layer as a second layer 8 and a coating layer for preventing copper oxidation as a third layer 9, and is configured by grounding the shield layer on the ground pattern 3. COPYRIGHT: (C)2005,JPO&NCIPI

Method of forming a fine wiring pattern

Abstract: PROBLEM TO BE SOLVED: To provide a method by which an extremely fine sintered copper-based wiring pattern can be formed by reducing nano-sized copper oxide particles in the pattern into nano-sized copper particles at a relatively low temperature after the pattern is drawn, by using a dispersed liquid of nano-sized copper oxide particles and baking the copper particles. SOLUTION: The dispersed liquid containing the nano-sized copper oxide particles having a mean particle diameter of 1-100 nm is applied to a substrate. Thereafter, the reduction of the nano-sized copper oxide particles and the formation of a sintered layer of the obtained copper particles are performed in the same step, by reducing the copper oxide particles through a reducing reaction using an active reactive species excited with plasma derived from a reducing gas, by heating the copper oxide particles contained in the applied layer to a temperature of ≤300°C in a plasma atmosphere produced under the presence of the reducing gas. Consequently, the utilizable range of the used substrate material is expanded largely, because the heat resistance required for the material is significantly relaxed. COPYRIGHT: (C)2004,JPO

The Deposition Characteristics of Accelerated Nonformaldehyde Electroless Copper Plating

Abstract: The deposition process of an electroless copper plating solution using sodium citrate as the main complexing agent and sodium hypophosphite as the reducing agent has been investigated. The deposit composition, structure, and catalytic activity for the oxidation of hypophosphite during the process have been investigated. Formamidine disulfide (fd) has been shown to accelerate the deposition rate of the electroless plating just as it does with electroless plating solutions using N-(2-hydroxyethyl)ethylenediaminetriacetic acid trisodium salt hydrate (HEDTA) as the complexing agent. For solutions with the mole ratio of 42, the deposition rate decreased with time and terminated after 90 min plating because the surface catalytic activity of the deposit had decreased with thickness. A copper deposit with total thickness of 6.48-6.59 μm was obtained after 90 min plating. The decrease in the deposition rate with time was mitigated by decreasing the mole ratio, holding the concentration of copper ions constant. An optimized electroless copper plating process with sustained deposition rate with time and high metal conductivity was developed. The bath was used in a fully additive high density wiring process. © 2003 The Electrochemical Society. All rights reserved.

Electroless Plating of Copper on Metal-Nitride Diffusion Barriers Initiated by Displacement Plating

Abstract: Copper is deposited on TaN and WN barrier layers by electroless plating without the need for activation preprocessing when substrates are (i) pretreated by wet chemical etching to remove surface oxides, and (ii) immersed in an electroless Cu plating solution containing glyoxylic acid as a reducing agent Electrical potential measurements indicate that the redox potentials of TaN and WN in the plating solution are lower than that of copper, driving displacement plating of Cu in the initial stage of deposition The adhesion between electroless-plated Cu and the TaN barrier layer after annealing is 011 kgf/cm as determined by a peeling test, which is sufficient for reliability during chemical mechanical polishing A damascene Cu interconnect was successfully fabricated without delamination and exhibited an electrical resistivity of 22 μΩ cm after annealing for a 042 μm wide interconnect track These results indicate that the proposed electroless process is suitable for the formation of a Cu seed layer prior to electrodeposition for the fabrication of ultralarge scale integrated interconnects © 2003 The Electrochemical Society All rights reserved

Electroless deposition of copper onto 4-mercaptobenzoic acid self-assembled on gold

Abstract: This paper reports the electroless deposition of copper, from a basic solution of copper sulfate, sodium hydrogentartrate, and formaldehyde, onto 4-mercaptobenzoic acid self-assembled on gold The copper was found to be ≈180 nm thick after a ≈30-min immersion Deposition did not occur on bare gold or self-assembled layers of 1-octadecanethiol or 3-mercaptobenzoic acid This latter observation suggests that the carboxylic acid functional group and its position play a role in the deposition process Infrared absorption spectroscopy was used to evaluate these layers On surfaces that were microcontact printed with 4-mercaptobenzoic acid, copper deposited only on the stamped areas

The influence of 2,2'-dipyridyl on non-formaldehyde electroless copper plating

Abstract: 2,2'-dipyridyl was introduced to improve the microstructure and properties of the copper deposits from electroless copper plating using hypophosphite as the reducing agent. The influences of 2,2'-dipyridyl on the deposit composition, structure, properties, and the electrochemical reactions of hypophosphite oxidation and cupric ion reduction have been investigated. The results show that the electroless deposition rate decreased significantly with the addition of 2,2'-dipyridyl in the plating solution and the color of the deposits changed from dark brown to a semi-bright, pink-tint. The deposits became uniform and compact. The deposits had a decreased crystallite size and intensified (111) plane orientation with the addition of 2,2'-dipyridyl in the plating bath. However, the resistivity and nickel content in the deposit were not effected by 2,2'-dipyridyl. The electrochemical measurements prove that 2,2'-dipyridyl inhibited significantly the catalytic oxidation of hypophosphite at the nickel active site on the deposit surface and increased the overpotential for cupric ion reduction, thus reducing the deposition rate and making the deposit become fine.

Tin-silver-copper plating solution, plating film containing the same, and method for forming the plating film

Abstract: A tin-silver-copper containing plating solution which comprises a medium having water as its primary component, a sulfonic acid, a tin ion, a copper ion and a silver ion, wherein concentrations of the silver ion, the tin ion and the copper ion are 0.015 to 0.1 mol/L, 0.21 to 2 mol/L and 0.002 to 0.02 mol/L, respectively; a plating film which comprises 2.6 to 3.4 wt % of silver, 0.4 to 0.7 wt % of Cu and the substantially balanced amount of tin; an electrolytic plating method for use in forming the above plating film from the above plating solution; and a soldering method using the plating film. The plating solution exhibits high stability, and the plating film has a low melting point.

High aspect ratio through-wafer interconnections for 3D-microsystems

Abstract: Closely spaced, through-wafer interconnects are of large interest in RF MEMS and MEMS packaging. In this paper, a suitable technique to realize large arrays of small size through-wafer holes is presented. This approach is based on macroporous silicon formation in combination with wafer thinning. Very high aspect ratio (/spl ges/ 100) structures are realized. The wafers containing the large arrays of 2-3/spl mu/m wide holes are thinned down to 200-150/spl mu/m by lapping and polishing. Copper electroplating is finally employed to realize arrays of high aspect ratio Cu plugs.

Method and system for analyte determination in metal plating baths

Abstract: The present invention relates generally to the field of electrolytic and electroless metal plating. A method and system for determining the presence of analytes in metal plating solutions using Raman spectroscopy is described. High absorbance plating bath samples are analyzed by Raman spectroscopy by minimizing the penetration depth of the incident light beam. A chemical auto-dosing system for controlling the concentration of one or more plating bath additives in a metal plating bath is also provided.

Anolyte for copper plating

Abstract: Embodiments of the invention provide a method for plating copper into features formed on a semiconductor substrate. The method includes positioning the substrate in a plating cell, wherein the plating cell includes a catholyte volume containing a catholyte solution, an anolyte volume containing an anolyte solution, an ionic membrane positioned to separate the anolyte volume from the catholyte volume, and an anode positioned in the anolyte volume. The method further includes applying a plating bias between the anode and the substrate, plating copper ions onto the substrate from the catholyte solution, and replenishing the copper ions plated onto the substrate from the catholyte solution with copper ions transported from the anolyte solution via the ionic membrane, wherein the catholyte solution has a copper concentration of greater than about 51 g/L.

Manufacturing method of wiring substrate

Abstract: PROBLEM TO BE SOLVED: To permit the manufacturing of a wiring substrate, thin and provided with a wiring pattern formed so as to have a high density. SOLUTION: A first metal layer 41 is bonded onto the surface of a core substrate 10 through a bonding layer 40a, then, a second metal layer 42 is adsorbed by vacuum to the first metal layer 41 to form a laminate 50, in which a wiring pattern 44 is electrically connected between the layers through an insulating layer 46 by a build-up method. Thereafter, vacuum between the first metal layer 41 and the second metal layer 42 is broken whereby the second metal layer 42 is separated from the first metal layer 41 together with the laminate 50 to form the wiring substrate by applying necessary treatments on the laminate 50. COPYRIGHT: (C)2004,JPO&NCIPI

Copper interconnects with metal capping layer and selective copper alloys

Abstract: High reliable copper interconnects are formed with copper or a low resistivity copper alloy filling relatively narrow openings and partially filling relatively wider openings and a copper alloy having improved electromigration resistance selectively deposited in the relatively wider openings. The filled openings are recessed and a metal capping layer deposited followed by CMP. The metal capping layer prevents diffusion along the copper-capping layer interface while the copper alloy filling the relatively wider openings impedes electromigration along the grain boundaries.

Wafer level electroless copper metallization and bumping process, and plating solutions for semiconductor wafer and microchip

Abstract: A process is used to produce copper bumps on a semiconductor chip or a wafer containing several microchips. The chip or wafer has a layer incorporating a plurality semiconductor devices and a passivation layer having openings. Conductive pads within the openings are in contact with the semiconductor devices. In the process, a conductive adhesive material is deposited onto the conductive pads to form adhesion layers. A conductive metal is deposited onto the adhesion layers to form barrier layers and the passivation layer is subjected to an acid dip solution to remove particles of the conductive adhesive material which can be attached to the passivation layer. Copper is then deposited onto the barrier layers to form the copper bump. Each one of the deposition steps are performed electrolessly. Furthermore, plating solutions and a wafer and a microchip produced by the above process and are provided.

Method of barrier-less integration with copper alloy

Abstract: A new method is provided for the creation of a barrier-free copper interconnect. A dual damascene structure is created in a layer of dielectric, a thin metal barrier layer is deposited. The metal barrier layer is oxidized, two layers are then deposited with the first layer comprising doped copper and the second layer comprising pure copper. The dual damascene structure is filled with copper, a thermal anneal is applied, stabilizing the deposited copper filling the dual damascene structure and forming metal oxide of the doped minority element. Excess copper is then removed from the dielectric.