Showing papers on "Electroplating published in 2001"

Electroplating of Amorphous Thin Films of Tungsten/Nickel Alloys

Abstract: The electroplating of amorphous Ni/W alloys is described. The aqueous plating solution consists of NiSO4, Na2WO4, and Na3Cit at pH = 8.0. The bath is operated at room temperature. By avoiding the use of NH4OH or any ammonium salt, it was possible to prepare alloys containing up to 50 a/o (76 w/o) W. XRD measurements revealed that amorphous alloys were obtained when the concentration of W in the alloy is 20−40 a/o. At lower concentrations of W the fcc substitutional solid solution Ni(1-x)Wx was formed. At higher concentration, an orthorhombic crystal structure corresponding to a 1/1 Ni/W alloy was observed. SEM and STM measurements supported the existence of the amorphous phase. The conditions under which amorphous alloys are expected to be formed preferentially are discussed. Thin films of the amorphous phase were prepared reproducibly at any tungsten concentration in the above range. Therefore, these alloys can be used for barrier or capping layers in the microelectronic industry for ULSI and MEMS applic...

Copper Electrodeposition: Principles and Recent Progress

Abstract: The capability of copper electroplating to produce void free filling of sub-micron high aspect ratio features has made it the process of choice for copper interconnect formation. Several aspects of copper electrodeposition including the basic electrochemistry and electrochemical kinetics, mass transport phenomena, potential gradients in solution, electrolyte composition, and the influence of various organic additives have been studied for over 50 years. Much of this basic understanding can be applied to development of integrated circuit (IC) copper electroplating processes. Other aspects of copper electroplating are unique to IC applications. These include the interactions of very thin seed layers with the electroplating process, the basic "bottom-up" filling mechanism necessary for seam free filling, and the metallurgical properties of sub-micron scale deposits. The dependence of IC filling processes upon plating bath chemistry and polarization characteristics are discussed in this paper.

Method for forming electromigration-resistant structures by doping

Abstract: A method for forming a copper conductor in an electronic structure by first depositing a copper composition in a receptacle formed in the electronic structure, and then adding impurities into the copper composition such that its electromigration resistance is improved is disclosed. In the method, the copper composition can be deposited by a variety of techniques such as electroplating, physical vapor deposition and chemical vapor deposition. The impurities which can be implanted include those of C, O, Cl, S and N at a suitable concentration range between about 0.01 ppm by weight and about 1000 ppm by weight. The impurities can be added by three different methods. In the first method, a copper seed layer is first deposited into a receptacle and an ion implantation process is carried out on the seed layer, which is followed by electroplating copper into the receptacle. In the second method, a copper seed layer is first deposited into a receptacle, a copper composition containing impurities is then electrodeposited into the receptacle and the electronic structure is annealed so that impurities diffuse into the copper seed layer. In the third method, a barrier layer is first deposited into a receptacle, dopant ions are then implanted into the barrier layer with a copper seed layer subsequently deposited on top of the barrier layer. An annealing process for the electronic structure is then carried out such that dopant ions diffuse into the copper seed layer. The present invention method may further include the step of ion-implanting at least one element into a surface layer of the copper conductor after the conductor is first planarized. The surface layer may have a thickness between about 30 Å and about 500 Å. At least one element may be selected from Co, Al, Sn, In, Ti and Cr.

Electroplating bath composition and method of using

Abstract: The present invention relates to a cobalt electroless plating bath composition and method of using it for microelectronic device fabrication. In one embodiment, the present invention relates to cobalt electroless plating in the fabrication of interconnect structures in semiconductor devices.

Effects of tungsten carbide thermal spray coating by HP/HVOF and hard chromium electroplating on AISI 4340 high strength steel

Abstract: In cases of decorative and functional applications, chromium results in protection against wear and corrosion combined with chemical resistance and good lubricity. However, pressure to identify alternatives or to improve conventional chromium electroplating mechanical characteristics has increased in recent years, related to the reduction in the fatigue strength of the base material and to environmental requirements. The high efficiency and fluoride-free hard chromium electroplating is an improvement to the conventional process, considering chemical and physical final properties. One of the most interesting, environmentally safer and cleaner alternatives for the replacement of hard chrome plating is tungsten carbide thermal spray coating, applied by the high velocity oxy-fuel (HVOF) process. The aim of this study was to analyse the effects of the tungsten carbide thermal spray coating applied by the HP/HVOF process and of the high efficiency and fluoride-free hard chromium electroplating (in the present paper called ‘accelerated’), in comparison to the conventional hard chromium electroplating on the AISI 4340 high strength steel behaviour in fatigue, corrosion, and abrasive wear tests. The results showed that the coatings were damaging to the AISI 4340 steel behaviour when submitted to fatigue testing, with the tungsten carbide thermal spray coatings showing the better performance. Experimental data from abrasive wear tests were conclusive, indicating better results from the WC coating. Regarding corrosion by salt spray test, both coatings were completely corroded after 72 h exposure. Scanning electron microscopy technique (SEM) and optical microscopy were used to observe crack origin sites, thickness and adhesion in all the coatings and microcrack density in hard chromium electroplatings, to aid in the results analysis.

Electroplating process for avoiding defects in metal features of integrated circuit devices

Abstract: Electroplating methods using an electroplating bath containing metal ions and a suppressor additive, an accelerator additive, and a leveler additive, together with controlling the current density applied to a substrate, avoid defects in plated films on substrates having features with a range of aspect ratios, while providing good filling and thickness distribution. The methods include, in succession, applying DC cathodic current densities optimized to form a conformal thin film on a seed layer, to provide bottom-up filling, preferentially on features having the largest aspect ratios, and to provide conformal plating of all features and adjacent field regions. Including a leveling agent in the electroplating bath produces films with better quality after subsequent processing.

Sealed-type remote pressure-monitoring device and method for fabricating the same

Abstract: Disclosed are a remote pressure-monitoring device and a preparing method thereof. The device comprises a metal electrode on a glass substrate, a capacitive sensor made of a silicon diaphragm, and an electroplated inductor electrically connected, in parallel, with the sensor. The glass substrate and the silicon are electrically bonded to form an LC resonator. For the fabrication of the device, first, a metal electrode which plays a role as a lower electrode for a capacitive pressure sensor is deposited on the glass substrate with the same coefficient of thermal expansion as that of silicon. An inductor is formed at a thickness by copper electroplating, surrounding the metal electrode at a predetermined distance. A silicon substrate is anisotropically etched to form a space for enveloping the metal electrode at a central area and to form a groove around the space. Boron ions are diffused lightly into the space and deeply into the groove to form etch barriers thereat, followed by bonding the silicon substrate on the glass substrate through an electrical contact in such a way that the metal electrode and the inductor are enveloped in the space and the groove, respectively. Then, the silicon substrate is etched out from its rear side to the extent that the etch barriers are exposed.

Apparatus for potential controlled electroplating of fine patterns on semiconductor wafers

Abstract: Controlled-potential electroplating provides an effective method of electroplating metals onto the surfaces of high aspect ratio recessed features of integrated circuit devices. Methods are provided to mitigate corrosion of a metal seed layer on recessed features due to contact of the seed layer with an electrolyte solution. The potential can also be controlled to provide conformal plating over the seed layer and bottom-up filling of the recessed features. For each of these processes, a constant cathodic voltage, pulsed cathodic voltage, or ramped cathodic voltage can be used. An apparatus for controlled-potential electroplating includes a reference electrode placed near the surface to be plated and at least one cathode sense lead to measure the potential at points on the circumference of the integrated circuit structure.

Pulse reverse electrodeposition for metallization and planarization of semiconductor substrates

Abstract: A smooth layer of a metal is electroplated onto a microrough electrically conducting substrate by immersing the substrate and a counterelectrode in an electroplating bath of the metal to be electroplated and passing a modulated reversing electric current between the electrodes. The current contains pulses that are cathodic with respect to said substrate and pulses that are anodic with respect to said substrate. The cathodic pulses have a duty cycle less than about 50% and said anodic pulses have a duty cycle greater than about 50%, the charge transfer ratio of the cathodic pulses to the anodic pulses is greater than one, and the frequency of said pulses ranges from about 10 Hertz to about 12000 Hertz. The plating bath is substantially devoid of levelers and may be devoid of brighteners.

Electroplating and characterization of cobalt-nickel-iron and nickel-iron for magnetic microsystems applications

Abstract: The magnetic properties of pulse reverse (PR) electroplated CoNiFe and DC electroplated NiFe are presented. CoNiFe is a very promising material for magnetic microsystems due to the possibility of achieving a high saturation flux density (Bs) and a low coercivity (Hc). A new bath formulation has been developed, which by means of PR electroplating makes it possible to deposit high Bs CoNiFe with a low residual stress level. The magnetic properties have been determined using a new simple measurement setup that allows for wafer level characterization. The results have been validated by comparison to measurements performed with a vibrating sample magnetometer (VSM).

Electrodeposition and characterisation of Ag–ZrO2 electroplated coatings

Abstract: Ag–ZrO2 electroplated coatings were produced using a classical DC technique in a silver cyanide bath with added ZrO2 particles Plating parameters, particle concentration and the stirring rate of the bath were systematically investigated in order to calculate the incorporation rate Vp of the particles in the deposit It was found that the relationships between Vp, current density and stirring rate were related to the particle concentration in the bath Moreover, it was established that the mechanical and tribological properties of coating composite, like hardness, friction coefficient and wear resistance increased with the increase in incorporation rate Vp

Electrodeposition of graphite-brass composite coatings and characterization of the tribological properties

Abstract: Co-deposition of Cu(Zn) and graphite powders with size less than 10 μm was studied. Electrocomposite coatings were prepared by means of the conventional electrodeposition (CECD) and the sediment co-deposition (SCD) techniques. Brass electroplating cyanide bath has been selected out of electrodeposition brass. The effect of parameters such as rate of agitation and current density on the composition of electrodeposition brass and also the effect of the concentration of graphite particles in brass bath, air agitation rate on graphite incorporation within brass matrix and deposition efficiency were studied. The wear and friction properties of G–Cu(Zn) composite coatings containing different percents of graphite particles were examined. The presence of graphite particles improved antifriction properties of composite coatings. It was shown that the composite coating containing approximately 3.7 (vol.%) graphite has the best tribological properties.

Method and associated apparatus for tilting a substrate upon entry for metal deposition

Abstract: An electro-chemical plating system is described. A method is performed by the electro-chemical plating system in which a seed layer formed on a substrate is immersed into an electrolyte solution. In one aspect, a substrate is immersed in the electrochemical plating system by tilting the substrate as it enters the electrolyte solution to limit the trapping or formation of air bubbles in the electrolyte solution between the substrate and the substrate holder. In another aspect, an apparatus is provided for electroplating that comprises a cell, a substrate holder, and an actuator. The actuator can displace the substrate holder assembly in the x and z directions and also tilt the substrate. In another aspect, a method is provided of driving a meniscus formed by electrolyte solution across a surface of a substrate. The method comprises enhancing the interaction between the electrolyte solution meniscus and the surface as the substrate is immersed into the electrolyte solution.

Method for achieving copper fill of high aspect ratio interconnect features

Abstract: One aspect of the invention provides a consistent metal electroplating technique to form void-less metal interconnects in sub-micron high aspect ratio features on semiconductor substrates. One embodiment of the invention provides a method for filling sub-micron features on a substrate, comprising reactive precleaning the substrate, depositing a barrier layer on the substrate using high density plasma physical vapor deposition; depositing a seed layer over the barrier layer using high density plasma physical vapor deposition; and electro-chemically depositing a metal using a highly resistive electrolyte and applying a first current density during a first deposition period followed by a second current density during a second period.

Apparatus and method for electrochemically depositing metal on a semiconductor workpiece

Abstract: A process for metallization of a workpiece, such as a semiconductor workpiece. In an embodiment, an alkaline electrolytic copper bath is used to electroplate copper onto a seed layer, electroplate copper directly onto a barrier layer material, or enhance an ultra-thin copper seed layer which has been deposited on the barrier layer using a deposition process such as PVD. The resulting copper layer provides an excellent conformal copper coating that fills trenches, vias, and other microstructures in the workpiece. When used for seed layer enhancement, the resulting copper seed layer provide an excellent conformal copper coating that allows the microstructures to be filled with a copper layer having good uniformity using electrochemical deposition techniques. Further, copper layers that are electroplated in the disclosed manner exhibit low sheet resistance and are readily annealed at low temperatures.

Methods and apparatus for controlled-angle wafer immersion

Abstract: The orientation of a wafer with respect to the surface of an electrolyte is controlled during an electroplating process. The wafer is delivered to an electrolyte bath along a trajectory normal to the surface of the electrolyte. Along this trajectory, the wafer is angled before entry into the electrolyte for angled immersion. A wafer can be plated in an angled orientation or not, depending on what is optimal for a given situation. Also, in some designs, the wafer's orientation can be adjusted actively during immersion or during electroplating, providing flexibility in various electroplating scenarios.

Microorigami: Fabrication of Small, Three-Dimensional, Metallic Structures

Abstract: Microcontact printing (μCP) and wet chemical etching generated two-dimensional (2D) patterns in thin silver films. Electroplating silver onto these patterns increased the structural integrity of the metal layer. Separating the metal film from the substrate resulted in free-standing, 2D structures. Folding of these structures along predesigned “hinges” produced three-dimensional (3D) objects. Additional electrodeposition of nickel welded hinges into position, strengthened the structure, and joined separate pieces. By printing onto cylindrical surfaces, it was possible to generate complex shapes efficiently and to minimize joining steps.

On-chip 3D air-core microinductor for high-frequency applications using deformation of sacrificial polymer

Abstract: A novel on-chip 3D air core micro-inductor, utilizing deformation of sacrificial thick polymer and conformal photoresist electrodeposition techniques, is reported. The bottom conductors are formed on silicon or glass substrate by metal electroplating through SU-8 polymeric mold. A thick SJR 5740 photoresist is then spun on and patterned to be a supporting mesa. Hard curing of such polymer mesa could significantly deform it into a cross-sectional bell-shape sacrificial core with graded profile in which is used to support top conductors formation. A layer of conformal electrodeposited photoresist (PEPR 2400) is then coated along the core's surface profile, patterned by standard optical lithography and filled up by metal electroplating. Finally, all polymeric molds including significantly deformed sacrificial core and electroplating bases are removed, resulting in an on-chip solenoid-type 3D air core micro-inductor. Since this new inductor has an air core and has only two contact points per turn, the core loss and equivalent series resistance are expected to be small, and hence, to give higher quality factor at high-frequency operation. Currently, high-frequency characterization of this on-chip inductor is under way.

Metal alloy compositions and plating methods related thereto

Abstract: The present invention provides inter alias electroplating compositions, methods for use of the compositions and products formed by the compositions. Electroplating compositions of the invention are characterized in significant part by a grain refiner/stabilizer additive comprising one or more non-aromatic compounds having π electrons that can be delocalized, e.g., an α,β unsaturated system or other conjugated system that contains a proximate electron-withdrawing group. Compositions of the invention provide enhanced grain refinement and increased stability in metal plating solutions, particularly in tin and tin alloy plating formulations.

Buried anode lithium thin film battery and process for forming the same

Abstract: A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from aprecursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential deposition of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

Electroplating chemistry on-line monitoring and control system

Abstract: The present invention provides methods and apparatus for analysis and monitoring of electrolyte bath composition. Based on analysis results, the invention controls electrolyte bath composition and plating hardware. Thus, the invention provides control of electroplating processes based on plating bath composition data. The invention accomplishes this by incorporating accurate bath component analysis data into a feedback control mechanism for electroplating. Bath electrolyte is treated and analyzed in a flow-through system in order to identify plating bath component concentrations and based on the results, the plating bath formulation and plating process are controlled.

Method and associated apparatus to mechanically enhance the deposition of a metal film within a feature

Abstract: A method and associated apparatus of electroplating an object and filling small features. The method comprises immersing the plating surface into an electrolyte solution and mechanically enhancing the concentration of metal ions in the electrolyte solution in the features. In one embodiment, the mechanical enhancement comprises mechanically vibrating the plating surface. In another embodiment, the mechanical enhancement comprises mechanically vibrating the electrolyte solution. In a further embodiment, the mechanical enhancement comprises increasing the pressure applied to the electrolyte solution.