US20110253545A1 - Method of direct electrodeposition on semiconductors - Google Patents

Method of direct electrodeposition on semiconductors Download PDF

Info

Publication number
US20110253545A1
US20110253545A1 US12/762,665 US76266510A US2011253545A1 US 20110253545 A1 US20110253545 A1 US 20110253545A1 US 76266510 A US76266510 A US 76266510A US 2011253545 A1 US2011253545 A1 US 2011253545A1
Authority
US
United States
Prior art keywords
semiconductor material
current density
mamps
electroplating bath
period
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/762,665
Other languages
English (en)
Inventor
Laura L. Kosbar
Xiaoyan Shao
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Business Machines Corp
Original Assignee
International Business Machines Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Priority to US12/762,665 priority Critical patent/US20110253545A1/en
Assigned to INTERNATIONAL BUSINESS MACHINES CORPORATION reassignment INTERNATIONAL BUSINESS MACHINES CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KOSBAR, LAURA L., SHAO, XIAOYAN
Priority to JP2011082976A priority patent/JP2011225991A/ja
Priority to KR1020110032449A priority patent/KR20110116982A/ko
Publication of US20110253545A1 publication Critical patent/US20110253545A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C25D7/12—Semiconductors
    • C25D7/123—Semiconductors first coated with a seed layer or a conductive layer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/02—Electroplating of selected surface areas
    • C25D5/024—Electroplating of selected surface areas using locally applied electromagnetic radiation, e.g. lasers
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/18—Electroplating using modulated, pulsed or reversing current
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0216—Coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/12—Electroplating: Baths therefor from solutions of nickel or cobalt
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C25D3/562—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of iron or nickel or cobalt
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the present invention relates to a method of depositing a metal or metal alloy on a surface of a semiconductor material, and more particularly to a method of electrodepositing a metal or metal alloy on a surface of a doped semiconductor material.
  • the method of the present disclosure can be integrated with any conventional solar cell fabrication process to provide a solar cell or photovoltaic cell including a doped semiconductor material having an electrodeposited metal or metal alloy on a surface thereof.
  • Electroplating is a plating process that uses electrical current to reduce cations of a desired material from a solution and coat an object, typically a conductive object, with a thin layer of the material, such as a metal. Electroplating is primarily used for depositing a layer of material to bestow a desired property (e.g., good electrical conductivity, abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities, etc.) to a surface that otherwise lacks that property.
  • a desired property e.g., good electrical conductivity, abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities, etc.
  • the process used in electroplating is called electrodeposition. It is analogous to a galvanic cell acting in reverse.
  • the part to be plated is typically the cathode of the circuit.
  • the anode is made of a metal to be plated on a part.
  • the anode is made of an inert metal, which can not be dissolved in the electrolyte during electrodeposition. Both components are immersed in a solution called an electrolyte containing one or more dissolved metal salts as well as other ions that permit the flow of electricity.
  • a battery or rectifier supplies a direct current to the anode, oxidizing the metal atoms that comprise it and allowing them to dissolve in the solution in the case of a soluble anode.
  • Electrodeposition directly on a semiconducting surface is more complicated than on a conductive surface, i.e., a metal.
  • a conductive surface i.e., a metal.
  • the presence of a bandgap on a semiconductor material makes nucleation more difficult and more sensitive to the states of the surface.
  • the dopant density will affect the nucleation rate. Any non-uniformity of the dopant profile will lead to non-uniform deposition of metals and metal alloys.
  • the deposition will occur preferentially at the sites with viable surface sites. See, for example, G. Oskam et al., Phy. Rev. Lett. 76 (1996), pg. 1521. This also leads to non-plated areas.
  • the present disclosure provides a method of electrodeposition of a metal or metal alloy on at least one surface of a semiconductor material.
  • the method of the present invention provides full coverage of an electrodeposited metallic film on the at least one surface of the semiconductor material.
  • the method of the present invention can be used to fully cover an n-emitter surface of a solar or photovoltaic cell. As such, an improved and lower cost technique for metallization is provided by the present disclosure which can be used in the photovoltaic industry in place of current screen printing processes.
  • the method of the present disclosure includes providing a semiconductor material.
  • the semiconductor material may be doped.
  • the semiconductor material may be undoped.
  • a metallic film is applied to at least one surface of the semiconductor material by an electrodeposition process.
  • the electrodeposition process employed uses current waveforms that apply a first current density for a first period of time, followed by a second current density for a second period of time, wherein the first current density is lower than the second current density.
  • the electrodeposition process of the present disclosure uses current waveforms that apply a low current density initially, and after a predetermined period of time, the current density is ramp-up to a high current density.
  • the applicants of the present disclosure have determined that the use of the aforementioned current waveform (e.g., low current density to high current density) overcomes the non-uniformity problem that exists during prior art electrodeposition processes.
  • the current waveform employed in the present disclosure can be a continuous ramp from a low current density to a high current density. In another embodiment, the current waveform can be a sequence of constant current plateaus, starting from a low current density to a high current density.
  • low current density as used throughout the present disclosure denotes a current density from 5 mAmps/cm 2 to 40 mAmps/cm 2 .
  • high current density as used throughout the present disclosure denotes a current density of greater than 40 mAmps/cm 2 , with a current density from greater than 40 mAmps/cm 2 to 200 mAmps/cm 2 being a typical range for the high current density.
  • light illumination can be used to increase metal nucleation and growth during the electrodeposition process.
  • light illumination can be used in embodiments in which solar or photovoltaic cells are to be fabricated to generate free electrons that can be used during the electrodeposition process.
  • FIG. 1 is a pictorial representation (through a cross sectional view) illustrating an initial structure including at least a semiconductor material that can be employed in one embodiment of the invention.
  • FIG. 2 is a pictorial representation (through a cross sectional view) depicting the initial structure of FIG. 1 after forming an optional patterned antireflective coating (ARC) on one surface of the semiconductor material.
  • ARC patterned antireflective coating
  • FIG. 3A is a pictorial representation (through a cross sectional view) depicting the initial structure of FIG. 1 after forming a metallic film on one surface of the semiconductor material utilizing an electrodeposition process in accordance with the present invention.
  • FIG. 3B is a pictorial representation (through a cross sectional view) depicting the structure of FIG. 2 after forming a metallic film on one surface of the semiconductor material utilizing an electrodeposition process in accordance with the present invention.
  • FIG. 4 is a SEM showing the Ni plating on a Si solar cell n-emitter grid surface using a high current density to plate the Ni as in accordance with a prior art method.
  • FIG. 5 is a SEM showing the Ni plating on a Si solar cell n-emitter grid surface using a waveform current density from low to high to plate the Ni as in accordance with the present disclosure.
  • FIG. 6 is a SEM showing the Ni plating on a Si solar cell n-emitter grid surface using a waveform current density from high to low to plate the Ni as in accordance with another prior art method.
  • the present disclosure provides a method of electrodeposition of a metal or metal alloy on at least one surface of a semiconductor material in which full coverage of an electrodeposited metallic film is achieved.
  • the method includes providing a semiconductor material.
  • a metallic film is then applied to at least one surface of the semiconductor material by an electrodeposition process, wherein current waveforms are employed that apply a low current density initially, and after a predetermined period of time, the current density is increased to a high current density.
  • the semiconductor material 10 has at least one surface 12 in which a metallic film will be subsequently formed thereon using the electrodeposition method of the present disclosure.
  • the semiconductor material 10 employed includes, but not limited to, Si, Ge, SiGe, SiC, SiGeC, GaAs, GaN, InAs, InP and all other III/V or II/VI compound semiconductors.
  • Semiconductor material 10 may also comprise an organic semiconductor or a layered semiconductor such as Si/SiGe, a silicon-on-insulator (SOI), a SiGe-on-insulator (SGOI) or a germanium-on-insulator (GOI).
  • the semiconductor material 10 is comprised of Si. In one embodiment, the semiconductor material 10 is comprised of a single crystalline semiconductor material. In another embodiment, the semiconductor material 10 is comprised of a multicrystalline semiconductor material. In another embodiment of the present application, the semiconductor material 10 may comprise a substrate in which at least one device, including a solar or photovoltaic cell, can be formed there upon.
  • the semiconductor material 10 may be doped with the same or different conductivity type, e.g., n-type and/or p-type dopant, undoped or contain doped and undoped regions therein.
  • the semiconductor material 10 includes a p-type semiconductor portion 10 A that includes a p-type dopant, and an overlying n-type semiconductor portion 10 B that includes an n-type dopant.
  • n-type dopant is used throughout the present disclosure to denote an atom from Group VA of the Periodic Table of Elements including, for example, P, As and/or Sb.
  • p-type dopant is used throughout the present disclosure to denote an atom from Group IIIA of the Periodic Table of Elements including, for example, B, Al, Ga and/or In.
  • the concentration of dopant within the semiconductor material may vary depending on the ultimate end use of the semiconductor material and the type of dopant atom being employed.
  • the p-type semiconductor portion 10 A of the semiconductor material 10 typically has a p-type dopant concentration from 1.0E12 atoms/cm 3 to 1E22 atoms/cm 3 , with a p-type dopant concentration from 1.0E16 atoms/cm 3 to 1.0E20 atoms/cm 3 being more typical.
  • the n-type semiconductor portion 10 B of the semiconductor material 10 typically has an n-type dopant concentration from 1.0E11 atoms/cm 3 to 1.0E22 atoms/cm 3 , with an n-type dopant concentration from 1.0E13 atoms/cm 3 to 1.0E20 atoms/cm 3 being more typical.
  • the n-type and/or p-type dopant can be introduced into the semiconductor material using techniques well known to those skilled.
  • the n-type and/or p-type dopant can be introduced into the semiconductor material by ion implantation, gas phase doping, liquid spray/mist doping, and/or out-diffusion of a dopant atom from an overlying sacrificial dopant material layer that can be formed on the substrate, and removed after the out-diffusion process.
  • the dopant(s) can be introduced into the semiconductor material 10 during the formation thereof.
  • an in-situ epitaxial growth process can be used to form a doped semiconductor material 10 .
  • the at least one surface 12 of the semiconductor material 10 may be non-textured or textured.
  • a textured (i.e., specially roughened) surface is typically used in cases in which the semiconductor material 10 is used in solar cell applications to increase the efficiency of light absorption.
  • the textured surface decreases the fraction of incident light lost to reflection relative to the fraction of incident light transmitted into the cell since photons incident on the side of an angled feature will be reflected onto the sides of adjacent angled features and thus have another chance to be absorbed.
  • the textured surface increases internal absorption, since light incident on an angled silicon surface will typically be deflected to propagate through the substrate at an oblique angle, thereby increasing the length of the path taken to reach the substrates back surface, as well as making it more likely that photons reflected from the substrate back surface will impinge on the front surface at angles compatible with total internal reflection and light trapping.
  • the texturing of the at least one surface 12 of the semiconductor material 10 can be performed utilizing conventional techniques well known in the art.
  • a KOH based solution can be used to texture the at least one surface 12 of the semiconductor material 10 .
  • texturing can be achieved by utilizing a HNO 3 /HF based solution on the at least one surface 12 of the semiconductor material 10 .
  • texturing can be achieved by utilizing a combination of reactive ion etching (RIE) and a mask comprising closely packed self-assembled polymer spheres.
  • RIE reactive ion etching
  • a metallic paste (not shown) is applied to a surface of the semiconductor material that is opposite the at least one surface in which the metallic film will be subsequently electrodeposited thereon.
  • the metallic paste which includes any conductive paste such as Al, Ag, or AlAg paste, is formed utilizing conventional techniques that are well known to those skilled in the art of solar cell fabrication. After applying the metallic paste, the metallic paste is heated to a sufficiently high temperature which causes the metallic paste to flow and form a metallic layer on the applied surface of the semiconductor material.
  • the Al paste is heated to a temperature from 700° C. to 900° C. which causes the Al paste to flow and form a metallic Al and AlSi layer.
  • the metallic Al and AlSi layer that is formed from the metallic paste serves as a conductive back surface field or backside electrical contact of a solar cell.
  • the optional patterned ARC 14 has at least one opening therein that exposes portions of the semiconductor material 10 .
  • the patterned ARC 14 that can be employed in the present invention includes any conventional ARC material including for example inorganic ARCs and organics ARCs.
  • the patterned ARC 14 can be formed utilizing techniques well known to those skilled in the art.
  • an ARC composition can be applied to the at least one surface 12 of the semiconductor material 10 utilizing a conventional deposition process including, for example, spin-on coating, dip coating, evaporation, chemical solution deposition, chemical vapor deposition (CVD), and plasma enhanced chemical vapor deposition (PECVD).
  • a post deposition baking step is usually employed to remove unwanted components, such as solvent, and to effect crosslinking.
  • the post deposition baking step of the ARC composition is typically, but not necessarily always, performed at a temperature from 80° C. to 300° C., with a baking temperature from 120° C. to 200° C. being more typical.
  • the as-deposited ARC composition may be subjected to a post deposition treatment to improve the properties of the entire layer or the surface of the ARC 14 .
  • This post deposition treatment can be selected from heat treatment, irradiation of electromagnetic wave (such as ultra-violet light), particle beam (such as an electron beam, or an ion beam), plasma treatment, chemical treatment through a gas phase or a liquid phase (such as application of a monolayer of surface modifier) or any combination thereof.
  • This post-deposition treatment can be blanket or pattern-wise.
  • the applied ARC composition can be patterned utilizing lithography and etching.
  • the lithographic process includes applying a photoresist (not shown) to an upper surface of the as-deposited ARC composition, exposing the photoresist to a desired pattern of radiation and developing the exposed photoresist utilizing a conventional resist developer. A patterned photoresist is thus provided.
  • the pattern in the photoresist is transferred to the as-deposited ARC composition utilizing an etching process such as, for example, dry etching or chemical wet etch.
  • the patterned photoresist is typically removed from the structure utilizing a conventional resist stripping process such as, for example, ashing.
  • the ARC layer can be patterned utilizing ink jet printing or laser ablation.
  • the patterned ARC 14 is typically employed in embodiments in which the semiconductor material 10 is to be used as a substrate of a solar or photovoltaic cell.
  • the metallic film 16 that is formed may comprise any metal or metal alloy.
  • the metallic film 16 is comprised of Ni, Co, Cu, Zn, Pt, Ag, Pd, Sn, Fe, In or alloys thereof.
  • the metallic film 16 is comprised of Ni, Co, Cu, Zn, Pt, Fe or alloys thereof.
  • the metallic film 16 is comprised of Ni or a Ni alloy.
  • the exposed surface(s) of the semiconductor material 10 is cleaned using a conventional cleaning process that is well known to those skilled in the art which is capable of removing surface oxides and other contaminants from the exposed surface(s) of the semiconductor material.
  • a diluted HF solution can be used to clean the exposed surface(s) of the semiconductor material 10 .
  • the electrodeposition method of the present application used in forming metallic film 16 includes the use of any conventional electrodeposition or electroplating apparatus that is well known to those skilled in the art.
  • a soluble or insoluble anode may be used.
  • the electrodeposition method of the present application also includes the use of any conventional electroplating bath (or composition).
  • the electroplating bath includes one or more sources of metal ions to plate metals.
  • the one or more sources of metal ions provide metal ions which include, but are not limited to Ni, Co, Cu, Zn, Pt, Ag, Pd, Sn, Fe and In. Alloys that can be electrodeposited (or plated) include, but are not limited to, binary and ternary alloys of the foregoing metals.
  • metals chosen from Ni, Co, Cu, Zn, Pt and Fe are plated from the electroplating bath. More typically, Ni or a Ni alloy is plated from the electroplating bath.
  • the one or more sources of metal ions that can be present in the electroplating bath include metal salts.
  • the metal salts that can be used include, but are not limited to, metal halides, metal nitrates, metal sulfates, metal sulfamates, metal alkane sulfonates, metal alkanol sulfonate, metal cyanides, metal acetates or metal citrates.
  • Copper (Cu) salts which may be used in the electroplating bath include, but are not limited to, one or more of copper halides, copper sulfates, copper phosphates, copper acetates, and copper citrate. Typically, copper sulfate, copper phosphates, or copper citrates, or mixtures thereof are used in the electroplating bath.
  • Tin (Sn) salts which may be used in the electroplating bath include, but are not limited to, one or more of tin sulfates, tin halides, tin alkane sulfonates such as tin methane sulfonate, tin ethane sulfonate, and tin propane sulfonate, tin aryl sulfonate such as tin phenyl sulfonate and tin toluene sulfonate, and tin alkanol sulfonate.
  • tin sulfate or tin alkane sulfonate is used in the electroplating bath.
  • Gold (Au) salts which may be used in the electroplating bath include, but are not limited to, one or more of gold trichloride, gold tribromide, gold cyanide, potassium gold chloride, potassium gold cyanide, sodium gold chloride and sodium gold cyanide.
  • Silver (Ag) salts which may be used in the electroplating bath include, but are not limited to, one or more of silver nitrate, silver chloride, silver acetate and silver bromate. Typically, silver nitrate is used in the electroplating bath.
  • Nickel (Ni) salts which may be used in the electroplating bath include, but are not limited to, one or more of nickel chloride, nickel sulfamate, nickel acetate, nickel ammonium sulfate, and nickel sulfate.
  • Palladium (Pd) salts which may be used in the electroplating bath include, but are not limited to, one or more of palladium chloride, palladium nitrate, palladium potassium chloride and palladium potassium chloride.
  • Platinum (Pt) salts which may be use include, but are not limited to, one or more of platinum tetrachloride, platinum sulfate and sodium chloroplatinate.
  • Indium (In) salts which may be used include, but are not limited to, one or more of indium salts of alkane sulfonic acids and aromatic sulfonic acids, such as methanesulfonic acid, ethanesulfonic acid, butane sulfonic acid, benzenesulfonic acid and toluenesulfonic acid, salts of sulfamic acid, sulfate salts, chloride and bromide salts of indium, nitrate salts, hydroxide salts, indium oxides, fluoroborate salts, indium salts of carboxylic acids, such as citric acid, acetoacetic acid, glyoxylic acid, pyruvic acid, glycolic acid, malonic acid, hydroxamic acid, iminodiacetic acid, salicylic acid, glyceric acid, succinic acid, malic acid, tartaric acid, hydroxybutyric acid, indium salts of amino acids, such as
  • Sources of cobalt (Co) ions include, but are not limited to, one or more of cobalt ammonium sulfate, cobalt acetate, cobalt sulfate and cobalt chloride.
  • Sources of zinc (Zn) ions include, but are not limited to, one or more of zinc bromate, zinc chloride, zinc nitrate and zinc sulfate.
  • Source of iron (Fe) include, but are not limited to, one or more of ferric or ferrous chloride, iron nitrate, iron sulfate, iron acetate, and iron sulfate.
  • the metal salts are included in the electroplating bath such that metal ions range in concentrations from 0.01 g/L to 200 g/L, or such as from 0.5 g/L to 150 g/L, or such as from 1 g/L to 100 g/L, or such as from 5 g/L to 50 g/L.
  • metal salts are included in amounts such that metal ion concentrations range from 0.01 to 100 g/L, more typically from 0.1 g/L to 60 g/L.
  • the electroplating bath that can be used may include one or more conventional diluents.
  • the electroplating bath is aqueous; however, conventional organic diluents may be used if desired.
  • Optional conventional electroplating bath additives also may be included.
  • Such additives include, but are not limited to, one or more of brighteners, suppressors, surfactants, inorganic acids, organic acids, brightener breakdown inhibition compounds, alkali metal salts, and pH adjusting compounds.
  • Additional additives may be included in the metal plating baths to tailor the performance of the metal plating for a particular substrate. Such additional additives may include, but are not limited to, levelers and compounds which affect throwing power.
  • Brighteners that can be employed include, but are not limited to, one or more of 3-mercapto-propylsulfonic acid sodium salt, 2-mercapto-ethanesulfonic acid sodium salt, bissulfopropyl disulfide (BSDS), N,N-dimethyldithiocarbamic acid (3-sulfopropyl) ester sodium salt (DPS), (O-ethyldithiocarbonato)-S-(3-sulfopropyl)-ester potassium salt (OPX), 3-[(amino-iminomethyl)-thio]-1-propanesulfonic acid (UPS), 3-(2-benzthiazolylthio)-1-propanesulfonic acid sodium salt (ZPS), the thiol of bissulfopropyl disulfide (MPS), sulfur compounds such as 3-(benzthiazoyl-2-thio)-propylsulfonic acid sodium salt, 3-mercaptopropane-1-sul
  • Suppressors include, but are not limited to, one or more of oxygen containing high molecular weight compounds such as carboxymethylcellulose, nonylphenolpolyglycol ether, octandiolbis-(polyalkylene glycolether), octanolpolyalkylene glycolether, oleic acidpolyglycol ester, polyethylenepropylene glycol, polyethylene glycol, polyethylene glycoldimethylether, polyoxypropylene glycol, polypropylene glycol, polyvinylalcohol, stearic acidpolyglycol ester, and stearyl alcoholpolyglycol ether.
  • Such suppressors may be included in the electroplating bath in conventional amounts, such as from 0.01 g/L to 10 g/L, or such as from 0.5 g/l to 5 g/L.
  • surfactants include, but are not limited to, nonionic surfactants such as alkyl phenoxy polyethoxyethanols. Other suitable surfactants containing multiple oxyethylene groups also may be used. Such surfactants include compounds of polyoxyethylene polymers having from as many as 20 to 7500 repeating units. Such compounds also may perform as suppressors. Also included in the class of polymers are both block and random copolymers of polyoxyethylene (EO) and polyoxypropylene (PO). Surfactants may be added in conventional amounts, as from 0.5 g/L to 20 g/L, or such as from 5 g/L to 10 g/L.
  • levelers include, but are not limited to, one or more of alkylated polyalkyleneimines and organic sulfo sulfonates. Examples of such compounds include 1-(2-hydroxyethyl)-2-imidazolidinethione (HIT), 4-mercaptopyridine, 2-mercaptothiazoline, ethylene thiourea, thiourea, 1-(2-hydroxyethyl)-2-imidazolidinethione (HIT) and alkylated polyalkyleneimines.
  • HIT 1-(2-hydroxyethyl)-2-imidazolidinethione
  • HIT 1-(2-hydroxyethyl)-2-imidazolidinethione
  • alkylated polyalkyleneimines alkylated polyalkyleneimines.
  • Such levelers are included in conventional amounts. Typically, such levelers are included in amounts of 1 ppb to 1 g/L, or such as from 10 ppb to 500 ppm.
  • inorganic and organic acids can be also included in the electroplating bath to increase the solution conductivity of the matrix and also to adjust the pH of the plating composition.
  • Inorganic acids include, but are not limited to, sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid.
  • Organic acids include, but are not limited to, alkane sulfonic acids, such a methane sulfonic acid. Acids are included in the electroplating bath in conventional amounts.
  • Alkali metal salts which may be included in the electroplating bath include, but are not limited to, sodium and potassium salts of halogens, such as chloride, fluoride and bromide. Typically chloride is used. Such alkali metal salts are used in conventional amounts.
  • the electroplating bath may also include hardeners, malleability, ductility and deposition modifiers, suppressants and the like.
  • the measured pH of the electroplating bath may range from ⁇ 1 to 14, or such as from ⁇ 1 to 8. Typically, the pH of the electroplating bath ranges from ⁇ 1 to 5, more typically, from ⁇ 1 to 3. Conventional buffering compounds may be included to control the pH of the electroplating bath.
  • the electroplating baths are typically maintained in a temperature range of from 20° C. to 110° C., with a temperature from 20° C. to 50° C. being more typical. Plating temperatures may vary depending on the metal to be plated.
  • the electrodeposition process employed in forming the metallic film 16 uses current waveforms that apply a low current density initially, and after a predetermined period of time, the current density is increased to a high current density.
  • the specific waveforms that are employed can be continuously applied or pulsed waveforms can be employed in the present invention. It has been determined by the applicants of the present disclosure that the use of the aforementioned current waveform (e.g., low current density to high current density) overcomes the non-uniformity problem that exists during prior art electrodeposition processes.
  • the low current density that is initially used to plate the metal or metal alloy from the plating bath is typically within a range from 1 mAmps/cm 2 to 40 mAmps/cm 2 , with a current density from 5 mAmps/cm 2 to 20 mAmps/cm 2 being more typical.
  • Plating within the low current density regime is typically performed for a time period from 5 seconds to 120 seconds, with a time period from 10 seconds to 60 seconds being more typical. After this initial period of time in which plating occurs using the low current density mentioned above, the current density is increased to a high current density regime.
  • the high current density regime typically employs a current density of greater than 40 mAmps/cm 2 , with a current density from greater than 40 mAmps/cm 2 to 200 mAmps/cm 2 being more typical.
  • Plating within the high current density regime is typically performed for a time period from 1 second to 1 hour, with a time period from 5 seconds to 300 seconds being more typical.
  • the increase from the low current density regime to the high current density regime may include a continuous ramp or it may include various ramp and soak cycles including a sequence of constant current plateaus.
  • the rate of increase can be from 1 mAmp/cm 2 /sec to 100 mAmp/cm 2 /sec.
  • the same ramp rate can be used in the various ramp and soak cycles and the soak at a desired current density may vary and is not critical to the practice of the present invention.
  • the thickness of the metallic film 16 that is electrodeposited using the above described conditions may vary depending on the type of metal being electrodeposition, the type of electroplating bath employed as well as the duration of the electrodeposition process itself.
  • the metallic film 16 that is formed from the electrodeposition described in this disclosure is from 50 ⁇ to 50000 ⁇ , with a thickness from 500 ⁇ to 5000 ⁇ being more typical.
  • the electrodeposition method described above provides complete coverage of the electrodeposited metallic film 16 on the exposed surface of the semiconductor material. By “complete coverage”, it is meant that no exposed substrate areas are present.
  • light illumination can be used to increase metal nucleation and growth during the electrodeposition process.
  • light illumination can be used in embodiments in which solar or photovoltaic cells are to be fabricated to generate free electrons that can be used during the electrodeposition process.
  • any conventional light source can be used.
  • the intensity of the light employed may vary and is typically greater than 5000 Lux, with an intensity of light from 10000 Lux to 50000 Lux being more typical.
  • the combination of the aforementioned waveform and light illumination enables one to provide complete coverage of a metallic film on the surface of a semiconductor substrate used in solar cell applications.
  • Ni was electrodeposited on a Si solar cell n-emitter surface similar to the one depicted in FIG. 2 of the present application using different waveforms.
  • a plating bath consisting of nickel sulfamate and boric acid was employed.
  • the temperature of the plating bath for each experiment was 21° C.
  • Ni was plated from the plating bath at a plating temperature of 21° C.
  • a high current density of 80 mAmps/cm 2 was employed to plate the Ni.
  • Plating was performed at the aforementioned high current density for a time period of 60 seconds. Using such plating conditions, a large area of the Si solar cell n-emitter surface was not covered as is shown in FIG. 4 .
  • a waveform current density (from a low current density to a high current density) in accordance with the present application was employed.
  • an initial current density of 20 mAmps/cm 2 was employed to initiate the plating of Ni.
  • the initial current density was held constant for a time period of about 40 seconds.
  • the current density was abruptly ramp-up to a current density of 80 mAmps/cm 2 .
  • Plating was performed at the aforementioned high current density for a time period of 10 seconds. Using such plating conditions, a complete coverage of Ni on the entire exposed surfaces of the Si solar cell n-emitter surface was observed as is shown in FIG. 5 .
  • a waveform current density opposite of that of the present application was employed. That is, a waveform current density from high to low was employed in comparative experiment 2.
  • an initial current density of 80 mAmps/cm 2 was employed to initiate the plating of Ni.
  • the initial current density was held constant for a time period of about 10 seconds.
  • the current density was decreased to a current density of 20 mAmps/cm 2 abruptly.
  • Plating was performed at the aforementioned low current density for a time period of 40 seconds. Using such plating conditions, an uneven nucleation and growth of Ni such as shown in FIG. 6 was observed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Electromagnetism (AREA)
  • Physics & Mathematics (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Optics & Photonics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Manufacturing & Machinery (AREA)
  • Electroplating Methods And Accessories (AREA)
  • Electrodes Of Semiconductors (AREA)
  • Photovoltaic Devices (AREA)
US12/762,665 2010-04-19 2010-04-19 Method of direct electrodeposition on semiconductors Abandoned US20110253545A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US12/762,665 US20110253545A1 (en) 2010-04-19 2010-04-19 Method of direct electrodeposition on semiconductors
JP2011082976A JP2011225991A (ja) 2010-04-19 2011-04-04 半導体に直接電着する方法
KR1020110032449A KR20110116982A (ko) 2010-04-19 2011-04-08 반도체 상에의 직접적인 전착 방법

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US12/762,665 US20110253545A1 (en) 2010-04-19 2010-04-19 Method of direct electrodeposition on semiconductors

Publications (1)

Publication Number Publication Date
US20110253545A1 true US20110253545A1 (en) 2011-10-20

Family

ID=44787375

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/762,665 Abandoned US20110253545A1 (en) 2010-04-19 2010-04-19 Method of direct electrodeposition on semiconductors

Country Status (3)

Country Link
US (1) US20110253545A1 (ja)
JP (1) JP2011225991A (ja)
KR (1) KR20110116982A (ja)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120091589A1 (en) * 2010-10-14 2012-04-19 International Business Machines Corporation Method to electrodeposit nickel on silicon for forming controllable nickel silicide
US20140008234A1 (en) * 2012-07-09 2014-01-09 Rohm And Haas Electronic Materials Llc Method of metal plating semiconductors
US20140110264A1 (en) * 2012-10-24 2014-04-24 Atomic Energy Council-Institute of Nuclear Research Light induced nickel plating method for p-type silicon and n/p solar cell material
US20150136228A1 (en) * 2011-06-14 2015-05-21 International Business Machines Corporation Processes for uniform metal semiconductor alloy formation for front side contact metallization and photovoltaic device formed therefrom
CN104934363A (zh) * 2014-03-17 2015-09-23 中芯国际集成电路制造(上海)有限公司 在半导体器件中形成金属结构的方法及互连层的制作方法
WO2016189258A1 (fr) * 2015-05-28 2016-12-01 Electricite De France Fabrication d'une cellule photovoltaïque en couches minces à contacts métalliques perfectionnés
WO2019179897A1 (en) * 2018-03-20 2019-09-26 Aveni Process for electrodeposition of cobalt
FR3079241A1 (fr) * 2018-03-20 2019-09-27 Aveni Procede d'electrodeposition de cobalt
US20200181791A1 (en) * 2015-01-16 2020-06-11 Hutchinson Technology Incorporated Gold electroplating solution and method

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
PT106470A (pt) * 2012-07-27 2014-01-27 Inst Superior Tecnico Processo de eletrodeposição de revestimentos de níquel-cobalto com estrutura dendrítica
KR101532139B1 (ko) * 2013-09-12 2015-06-30 전남대학교산학협력단 씨아이지에스 박막의 제조방법
JP6908240B2 (ja) * 2017-06-13 2021-07-21 住友電工デバイス・イノベーション株式会社 窒化物半導体トランジスタの製造方法及び窒化物半導体トランジスタ
US11380604B2 (en) 2019-11-26 2022-07-05 Toyota Motor Engineering & Manufacturing North America, Inc. Methods of forming electronic assemblies with textured surfaces using low current density electroplating

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3067114A (en) * 1953-12-02 1962-12-04 Philco Corp Semiconductive devices and methods for the fabrication thereof
US4385971A (en) * 1981-06-26 1983-05-31 Rca Corporation Electrolytic etch for eliminating shorts and shunts in large area amorphous silicon solar cells
US6140241A (en) * 1999-03-18 2000-10-31 Taiwan Semiconductor Manufacturing Company Multi-step electrochemical copper deposition process with improved filling capability
US6176983B1 (en) * 1997-09-03 2001-01-23 Vlsi Technology, Inc. Methods of forming a semiconductor device
US6793796B2 (en) * 1998-10-26 2004-09-21 Novellus Systems, Inc. Electroplating process for avoiding defects in metal features of integrated circuit devices
US20070190341A1 (en) * 2006-02-14 2007-08-16 Nec Electronics Corporation Semiconductor device and method for manufacturing same
US20080142894A1 (en) * 2005-01-27 2008-06-19 International Business Machines Corporation Gate stack engineering by electrochemical processing utilizing through-gate-dielectric current flow
US20080283404A1 (en) * 2007-05-14 2008-11-20 Nec Electronics Corporation Method of manufacturing semiconductor device to decrease defect number of plating film
US20090057154A1 (en) * 2006-05-04 2009-03-05 International Business Machines Corporation Apparatus and method for electrochemical processing of thin films on resistive substrates
US20090071836A1 (en) * 2007-09-17 2009-03-19 International Business Machines Corporation Method of electrodepositing germanium compound materials on a substrate

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3694594B2 (ja) * 1998-09-03 2005-09-14 株式会社荏原製作所 微細孔および／または微細溝を有する基材の孔埋めめっき方法
JP3348705B2 (ja) * 1999-09-28 2002-11-20 株式会社村田製作所 電極形成方法
JP4196662B2 (ja) * 2002-12-10 2008-12-17 凸版印刷株式会社 構造傾斜銅箔及びその作製方法、並びにエッチング方法、銅箔パターン、保存方法
JP4045997B2 (ja) * 2003-04-07 2008-02-13 松下電器産業株式会社 チップ形電子部品のバレルめっき方法
JP2007131875A (ja) * 2005-11-08 2007-05-31 Fujifilm Corp 金属膜形成方法及び金属パターン形成方法
US8372744B2 (en) * 2007-04-20 2013-02-12 International Business Machines Corporation Fabricating a contact rhodium structure by electroplating and electroplating composition
EP2157209B1 (en) * 2008-07-31 2014-10-22 Rohm and Haas Electronic Materials LLC Inhibiting Background Plating
JP2011023487A (ja) * 2009-07-14 2011-02-03 Renesas Electronics Corp 半導体装置及び半導体装置の製造方法

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3067114A (en) * 1953-12-02 1962-12-04 Philco Corp Semiconductive devices and methods for the fabrication thereof
US4385971A (en) * 1981-06-26 1983-05-31 Rca Corporation Electrolytic etch for eliminating shorts and shunts in large area amorphous silicon solar cells
US6176983B1 (en) * 1997-09-03 2001-01-23 Vlsi Technology, Inc. Methods of forming a semiconductor device
US6793796B2 (en) * 1998-10-26 2004-09-21 Novellus Systems, Inc. Electroplating process for avoiding defects in metal features of integrated circuit devices
US6140241A (en) * 1999-03-18 2000-10-31 Taiwan Semiconductor Manufacturing Company Multi-step electrochemical copper deposition process with improved filling capability
US20080142894A1 (en) * 2005-01-27 2008-06-19 International Business Machines Corporation Gate stack engineering by electrochemical processing utilizing through-gate-dielectric current flow
US20070190341A1 (en) * 2006-02-14 2007-08-16 Nec Electronics Corporation Semiconductor device and method for manufacturing same
US20090057154A1 (en) * 2006-05-04 2009-03-05 International Business Machines Corporation Apparatus and method for electrochemical processing of thin films on resistive substrates
US20080283404A1 (en) * 2007-05-14 2008-11-20 Nec Electronics Corporation Method of manufacturing semiconductor device to decrease defect number of plating film
US20090071836A1 (en) * 2007-09-17 2009-03-19 International Business Machines Corporation Method of electrodepositing germanium compound materials on a substrate

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120091589A1 (en) * 2010-10-14 2012-04-19 International Business Machines Corporation Method to electrodeposit nickel on silicon for forming controllable nickel silicide
US8492899B2 (en) * 2010-10-14 2013-07-23 International Business Machines Corporation Method to electrodeposit nickel on silicon for forming controllable nickel silicide
US9608134B2 (en) * 2011-06-14 2017-03-28 International Business Machines Corporation Processes for uniform metal semiconductor alloy formation for front side contact metallization and photovoltaic device formed therefrom
US10170644B2 (en) 2011-06-14 2019-01-01 International Business Machines Corporation Processes for uniform metal semiconductor alloy formation for front side contact metallization and photovoltaic device formed therefrom
US20150136228A1 (en) * 2011-06-14 2015-05-21 International Business Machines Corporation Processes for uniform metal semiconductor alloy formation for front side contact metallization and photovoltaic device formed therefrom
US20140008234A1 (en) * 2012-07-09 2014-01-09 Rohm And Haas Electronic Materials Llc Method of metal plating semiconductors
US20140110264A1 (en) * 2012-10-24 2014-04-24 Atomic Energy Council-Institute of Nuclear Research Light induced nickel plating method for p-type silicon and n/p solar cell material
CN104934363A (zh) * 2014-03-17 2015-09-23 中芯国际集成电路制造(上海)有限公司 在半导体器件中形成金属结构的方法及互连层的制作方法
US20200181791A1 (en) * 2015-01-16 2020-06-11 Hutchinson Technology Incorporated Gold electroplating solution and method
WO2016189258A1 (fr) * 2015-05-28 2016-12-01 Electricite De France Fabrication d'une cellule photovoltaïque en couches minces à contacts métalliques perfectionnés
FR3036852A1 (fr) * 2015-05-28 2016-12-02 Electricite De France Fabrication d'une cellule photovoltaique en couches minces a contacts metalliques perfectionnes
WO2019179897A1 (en) * 2018-03-20 2019-09-26 Aveni Process for electrodeposition of cobalt
FR3079241A1 (fr) * 2018-03-20 2019-09-27 Aveni Procede d'electrodeposition de cobalt
FR3079242A1 (fr) * 2018-03-20 2019-09-27 Aveni Procede d'electrodeposition de cobalt
CN111771016A (zh) * 2018-03-20 2020-10-13 阿文尼公司 用于钴的电沉积的方法
US11384445B2 (en) 2018-03-20 2022-07-12 Aveni Process for electrodeposition of cobalt

Also Published As

Publication number Publication date
JP2011225991A (ja) 2011-11-10
KR20110116982A (ko) 2011-10-26

Similar Documents

Publication Publication Date Title
US20110253545A1 (en) Method of direct electrodeposition on semiconductors
US10269993B2 (en) Use of metal phosphorus in metallization of photovoltaic devices and method of fabricating same
US8901414B2 (en) Photovoltaic cells with copper grid
US7955977B2 (en) Method of light induced plating on semiconductors
US8884159B2 (en) Photovoltaic devices with metal semiconductor alloy metallization
US10170644B2 (en) Processes for uniform metal semiconductor alloy formation for front side contact metallization and photovoltaic device formed therefrom
CN103025916B (zh) 用于金属硫化物层的湿化学沉积的浴沉积溶液及相关生产方法
WO2012028415A1 (en) Electrodeposition methods of gallium and gallium alloy films and related photovoltaic structures
US9076657B2 (en) Electrochemical etching of semiconductors
KR20130091290A (ko) 금속 부착을 개선하기 위한 활성화 공정
US8604337B2 (en) Method to evaluate effectiveness of substrate cleanness and quantity of pin holes in an antireflective coating of a solar cell
US9246024B2 (en) Photovoltaic device with aluminum plated back surface field and method of forming same
US8865502B2 (en) Solar cells with plated back side surface field and back side electrical contact and method of fabricating same

Legal Events

Date Code Title Description
AS Assignment

Owner name: INTERNATIONAL BUSINESS MACHINES CORPORATION, NEW Y

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KOSBAR, LAURA L.;SHAO, XIAOYAN;REEL/FRAME:024254/0652

Effective date: 20100416

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION