Alkali Metal Hydroxide Containing Patents (Class 252/79.5)
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Patent number: 6821352Abstract: A composition for removing etching residue and a method using same are disclosed herein. In one aspect, there is provided a method for removing etching residue from a substrate comprising: contacting the substrate with a composition comprising water, an organic dicarboxylic acid, a buffering agent, a fluorine source, and optionally a water miscible organic solvent.Type: GrantFiled: November 26, 2003Date of Patent: November 23, 2004Assignee: Air Products and Chemicals, Inc.Inventors: Roberto John Rovito, David Barry Rennie, Dana L. Durham
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Patent number: 6783690Abstract: A method of stripping silver from a printed circuit board without attacking the underlying base metal. The stripping solution comprises an oxidizing agent, an alkaline pH adjuster, and a silver solubilizing agent. After the silver has been sufficiently removed from the surface of the printed circuit board, the printed circuit board is contacted with a neutralization solution to remove any smut remaining on the surface. The silver stripping solution does not contain cyanide or chromium and does not require the use of anodic current.Type: GrantFiled: March 25, 2002Date of Patent: August 31, 2004Inventors: Donna M. Kologe, Raymond A. Letize, Brian Larson
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Patent number: 6767477Abstract: Write head coils for magnetic disk systems are commonly formed through electroplating onto a seed layer in the presence of a photoresist mask. It is then necessary to remove the seed layer everywhere except under the coil itself. The present invention achieves this through etching in a solution of ammonium persulfate to which has been added the complexing agent 1,4,8,11 tetraazundecane. This suppresses the reduction of Cu++ to Cu, thereby increasing the dissolution rate of copper while decreasing that of nickel-iron. Two ways of implementing this are described—adding the complexing agent directly to the ammonium persulfate and introducing the 1,4,8,11 tetraazundecane through a dipping process that precedes conventional etching in the ammonium persulfate.Type: GrantFiled: June 12, 2002Date of Patent: July 27, 2004Assignee: Headway Technologies, Inc.Inventors: Xue Hua Wu, Wensen Li, Si-Tuan Lam, Henry C. Chang, Kochan Ju, Jei-Wei Chang
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Patent number: 6758872Abstract: A polishing slurry prepared by dispersing in a dispersion medium, abrasive grains comprised of a material having a solubility in the dispersion medium at 25° C., of 0.001 g/100 g or higher is used to effectively remove any abrasive grains standing adherent to the surfaces of objects to be polished or the interiors of polishing apparatus after polishing.Type: GrantFiled: March 5, 2001Date of Patent: July 6, 2004Assignee: Hitachi, Ltd.Inventors: Katsuhiro Ota, Akio Saito
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Patent number: 6753001Abstract: A gel composition for use in etching the surfaces of teeth in preparation for prophylaxis, repair, or restoration, comprising an aqueous solution of an effective quantity of an acid; and a colloidal silica sol, wherein the silica portion of the sol comprises from about 3 to about 20 weight percent of the total etchant composition.Type: GrantFiled: January 21, 2003Date of Patent: June 22, 2004Assignee: Pentron Clinical Technologies, LLCInventors: Weitao Jia, Shuhua Jin
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Publication number: 20040018728Abstract: A solution for platinum chemical mechanical polishing is disclosed. Further, a method for forming Pt patterns is disclosed which utilizes the disclosed Pt-CMP solution which contains an alkali aqueous solution and an oxidizer which improves the polishing rate and polishing characteristics of Pt which forms a lower electrode of a metal capacitor.Type: ApplicationFiled: June 12, 2003Publication date: January 29, 2004Inventor: Woo Jin Lee
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Patent number: 6677286Abstract: Compositions containing water, an organic dicarboxylic acid, a buffering agent and fluorine source and optionally a water miscible organic solvent are capable of removing etching residue.Type: GrantFiled: July 10, 2002Date of Patent: January 13, 2004Assignee: Air Products and Chemicals, Inc.Inventors: Roberto John Rovito, David Barry Rennie, Dana L. Durham
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Patent number: 6656370Abstract: A process for the manufacture of printed circuit boards is disclosed wherein a plated silver deposit is used both as an etch resist and as a final finish for enhancing the solderability of the copper circuits. An aqueous alkaline etchant which is free of halide ions is proposed as being particularly compatible with the silver etch resist/final finish.Type: GrantFiled: October 13, 2000Date of Patent: December 2, 2003Inventors: Lenora Toscano, Raymond Letize
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Patent number: 6645051Abstract: A polishing composition for a substrate to be used for a memory hard disk, which comprises the following components (a) to (d): (a) water, (b) at least one compound selected from the group consisting of a polyoxyethylene polyoxypropylene alkyl ether and a polyoxyethylene polyoxypropylene copolymer, (c) at least one compound selected from the group consisting of nitric acid, nitrous acid, sulfuric acid, hydrochloric acid, molybdic acid, sulfamic acid, glycine, glyceric acid, mandelic acid, malonic acid, ascorbic acid, glutamic acid, glyoxylic acid, malic acid, glycolic acid, lactic acid, gluconic acid, succinic acid, tartaric acid, maleic acid and citric acid, and their salts, and (d) at least one abrasive selected from the group consisting of aluminum oxide, silicon dioxide, cerium oxide, zirconium oxide, titanium oxide, silicon nitride and silicon carbide.Type: GrantFiled: November 7, 2001Date of Patent: November 11, 2003Assignee: Fujimi IncorporatedInventors: Hiroyasu Sugiyama, Tomoaki Ishibashi, Toshiyuki Takahashi
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Patent number: 6627107Abstract: A new slurry for shallow trench isolation (STI) processing in the chemical mechanical planarization (CMP) in microelectronic industry comprising an aqueous medium having an abrasive; and a compound which has a carboxylic group and an electrophilic functional group. The combination of ceria and/or titania with amino acids to obtain polishing selectivity's greater than 5:1. CMP is used for removing the excess oxide and planarizing the substrate and the trench. The silicon nitride acts as a stop layer, preventing the polishing of underlying silicon substrate.Type: GrantFiled: July 10, 2002Date of Patent: September 30, 2003Assignee: Eastman Kodak CompanyInventors: Ramanathan Srinivasan, Suryadevara V. Babu, William G. America, Yie-Shein Her
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Patent number: 6616514Abstract: The present invention provides a chemical mechanical polishing slurry for use in removing a first substance from a surface of an article in preference to silicon nitride by chemical mechanical polishing. The chemical mechanical polishing slurry according to the invention includes an abrasive, an aqueous medium, and an organic polyol that does not dissociate protons, said organic polyol including a compound having at least three hydroxyl groups that are not dissociable in the aqueous medium, or a polymer formed from at least one monomer having at least three hydroxyl groups that are not dissociable in the aqueous medium. In the preferred embodiment, ceria particles are used as the abrasive and the organic polyol is selected from the group consisting of mannitol, sorbitol, mannose, xylitol, sorbose, sucrose, and dextrin. The chemical mechanical polishing slurry can further optionally include acids or bases for adjusting the pH within an effective range of from about 2 to about 12.Type: GrantFiled: June 3, 2002Date of Patent: September 9, 2003Assignee: Ferro CorporationInventors: Brian Edelbach, Eric Oswald, Yie-Shein Her
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Patent number: 6599370Abstract: The invention provides aqueous alkaline compositions useful in the microelectronics industry for stripping or cleaning semiconductor wafer substrates by removing photoresist residues and other unwanted contaminants. The compositions typically contain (a) one or more metal ion-free bases at sufficient amounts to produce a pH of about 10-13 and one or more bath stabilizing agents having at least one pKa in the range of 10-13 to maintain this pH during use; (b) optionally, about 0.01% to about 5% by weight (expressed as % SiO2) of a water-soluble metal ion-free silicate; (c) optionally, about 0.01% to about 10% by weight of one or more chelating agents; (d) optionally, about 0.01% to about 80% by weight of one or more water-soluble organic co-solvents; and (e) optionally, about 0.01% to about 1% by weight of a water-soluble surfactant.Type: GrantFiled: May 16, 2001Date of Patent: July 29, 2003Assignee: Mallinckrodt Inc.Inventor: David C. Skee
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Publication number: 20030133827Abstract: This invention provides a method of treating a dry or processed fluid pipe line susceptible to the build-up of iron sulfide deposits by complexing the iron sulfide in the pipe lines. The method of the present invention introduces the composition on a continuous or a batch basis to a gas pipe line. The composition is made of a solution of 1) water, 2) [tetrakis (hydroxymethyl) phosphonium] sulfate or chloride, and 3) a soluble ammonium salt, such as ammonium chloride or the like.Type: ApplicationFiled: January 10, 2002Publication date: July 17, 2003Inventor: Mark Andrew Mattox
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Patent number: 6585825Abstract: The invention provides aqueous alkaline compositions useful in the microelectronics industry for stripping or cleaning semiconductor wafer substrates by removing photoresist residues and other unwanted contaminants. The compositions typically contain (a) one or more metal ion-free bases at sufficient amounts to produce a pH of about 11-13 and one or more bath stabilizing agents to maintain this pH during use; (b) optionally, about 0.01% to about 5% by weight (expressed as % SiO2) of a water-soluble metal ion-free silicate; (c) optionally, about 0.01% to about 10% by weight of one or more chelating agents; (d) optionally, about 0.01% to about 80% by weight of one or more water-soljuble organic co-solvents; and (e) optionally, about 0.01% to about 1% by weight of a water-soluble surfactant.Type: GrantFiled: October 16, 2000Date of Patent: July 1, 2003Assignee: Mallinckrodt IncInventor: David C. Skee
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Patent number: 6582623Abstract: A polishing composition comprising a dispersion of silane modified abrasive particles formed by combining at least one metal oxide abrasive having at least one surface metal hydroxide with at least one silane compound and methods for polishing substrate features such as metal features and oxide features using the polishing compositions.Type: GrantFiled: July 5, 2000Date of Patent: June 24, 2003Assignee: Cabot Microelectronics CorporationInventors: Steven K. Grumbine, Christopher C. Streinz, Shumin Wang
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Patent number: 6569349Abstract: A method and composition for planarizing a substrate. The composition includes one or more chelating agents, one or more oxidizers, one or more corrosion inhibitors, a polar solvent, and deionized water. The composition may further comprise one or more surfactants, one or more agents to adjust the pH and/or abrasive particles. The method comprises planarizing a substrate using a composition including a polar solvent.Type: GrantFiled: October 23, 2000Date of Patent: May 27, 2003Assignee: Applied Materials Inc.Inventors: Yuchun Wang, Rajeev Bajaj, Fred C. Redeker
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Patent number: 6569215Abstract: An object of the present invention is to provide a composition for polishing a magnetic disk substrate that is used as a storage device for a computer or the like, and is capable of producing a magnetic disk substrate polished with high precision suitable for use in combination with a magnetic head that floats at a low level. Another object of the present invention is to provide a method of producing the composition for polishing the magnetic disk substrate. A polishing composition includes alkali metal ions, abrasive grains, a carboxylic acid, an oxidizing agent, and an anti-gelling agent contained in an aqueous medium. In a method of the present invention for preparing a polishing composition, a pH value of an aqueous medium, in which abrasive grains, a carboxylic acid, an oxidizing agent, and an anti-gelling agent are contained, is adjusted to a range of about 1 to about 5 by the addition of alkali metal hydroxide to the aqueous medium.Type: GrantFiled: April 17, 2001Date of Patent: May 27, 2003Assignee: Showa Denko Kabushiki KaishaInventor: Norihiko Miyata
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Patent number: 6537916Abstract: A method of removing Chemical Mechanical Polishing (CMP) residue from a semiconductor substrate is disclosed. The semiconductor substrate with the CMP residue on a surface is placed within a pressure chamber. The pressure chamber is then pressurized. Supercritical carbon dioxide and a solvent are introduced into the pressure chamber. The supercritical carbon dioxide and the chemical are maintained in contact with the semiconductor substrate until the CMP residue is removed from the semiconductor substrate. The pressure chamber is then flushed and vented.Type: GrantFiled: October 18, 2001Date of Patent: March 25, 2003Assignee: Tokyo Electron LimitedInventors: William H. Mullee, Marc de Leeuwe, Glenn A. Roberson, Jr.
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Patent number: 6531071Abstract: A contact is defined by an opening etched into borophosphosilicate glass (BPSG) down to a silicon substrate. In a contact cleaning process designed to remove native oxide at the bottom of the contact with little effect on the BPSG, the contact is dipped in an etch retardant before being dipped in a cleaning solution containing both the etch retardant and an etchant. The dip in etch retardant modifies the surface of the BPSG, thereby lessening the enhanced etching experienced during the initiation of the dip into the etchant/etch retardant cleaning solution. Results of a etchant/etch retardant clean, both with and without the prepassivation, can be illustrated on a graph depicting the change in contact diameter as a function of dip time. Specifically, the results define “best fit” lines on that graph.Type: GrantFiled: January 4, 2000Date of Patent: March 11, 2003Assignee: Micron Technology, Inc.Inventor: Satish Bedge
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Patent number: 6527819Abstract: A chemical mechanical polishing slurry and method for using the slurry for polishing copper, barrier material and dielectric material that comprises a first and second slurry. The first slurry has a high removal rate on copper and a low removal rate on barrier material. The second slurry has a high removal rate on barrier material and a low removal rate on copper and dielectric material. The first and second slurries at least comprise silica particles, an oxidizing agent, a corrosion inhibitor, and a cleaning agent.Type: GrantFiled: December 18, 2001Date of Patent: March 4, 2003Assignee: Advanced Technology Materials, Inc.Inventors: William A. Wojtczak, Thomas H. Baum, Long Nguyen, Cary Regulski
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Patent number: 6468913Abstract: In accordance with the invention, there is provided a chemical-mechanical polishing slurry for polishing a substrate. The slurry is comprised primarily of abrasive particles and an oxidizing agent, wherein the slurry exhibits a stability having a shelf life of at least 30 days.Type: GrantFiled: July 8, 2000Date of Patent: October 22, 2002Assignee: Arch Specialty Chemicals, Inc.Inventors: Anthony Mark Pasqualoni, Deepak Mahulikar
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Cleaning composition containing tetraalkylammonium salt and use thereof in semiconductor fabrication
Patent number: 6468951Abstract: A composition prepared from water, hydrofluoric acid (HF) and tetraalkylammonium hydroxide (TAAH, preferably tetramethylammonium hydroxide (TMAH)) or tetraalkylammonium fluoride and solvent with or without HF or TAAH is used to clean residue from a semiconductor wafer, where the residue is formed as a result of a planarization process, such as chemical mechanical polishing. Incorporation of TMAH into an aqueous HF composition retards the rate at which the composition dissolves borophosphosilicate (BPSG) without effecting the rate at which silica is dissolved. Thus, the aqueous HF/TMAH composition may be used to completely remove silica-containing residue from a BPSG surface, with a tolerable level of BPSG removal.Type: GrantFiled: May 1, 2000Date of Patent: October 22, 2002Assignee: Micron Technology, Inc.Inventors: Eric K. Grieger, Michael T. Andreas, Michael A. Walker -
Patent number: 6461534Abstract: Lead brass components for potable water distribution circuits (e.g., plumbing components made of CuZn39Pb3, containing 3% Pb), also chronium plated ones, are subjected to a lead-selective surface etching to reduce, in operation, the release of Pb caused by Pb surface “smearing”, resulting either from machining or molding; said elements are firstly contacted by an aqueous solution of an acid capable of forming soluble Pb salts, preferably a non-oxidizing solution, by simply dipping the components in the solution, e.g., a solution of 0.1 M sulfamic acid, at 20°−50° C. for 10 to 50 minutes, and, subsequently, the elements are passivated by immersion into a strong base aqueous solution, e.g., a solution of 0.1 M NaOH at 20°−25° C., for approximately 10 minutes; in this manner, plumbing components made of a copper based alloy containing Pb are obtained, which components, after 15 days of test according to US NSF STD61 procedure, release Pb in an amount less than 0.Type: GrantFiled: April 30, 2001Date of Patent: October 8, 2002Assignee: Europa Metalli S. P. A.Inventor: Aldo Giusti
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Patent number: 6451218Abstract: A new and improved etching solution and etching method provide wet chemical pyramidal texture etching of (100) silicon surfaces. A uniform and completely pyramidal texture etching of silicon surfaces is achieved with an etching solution including water, an alkaline reagent, and isopropanol together with an aqueous alkaline ethylene glycol solution.Type: GrantFiled: March 18, 1999Date of Patent: September 17, 2002Assignee: Siemens Solar GmbHInventor: Konstantin Holdermann
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Publication number: 20020125461Abstract: The invention provides a polishing system and method for polishing or planarizing a substrate. The polishing system comprises (i) a liquid carrier, (ii) ammonium oxalate, (iii) a hydroxy coupling agent, and (iv) a polishing pad and/or an abrasive. The polishing method comprises contacting at least a portion of a substrate with the polishing system and polishing the portion of the substrate therewith.Type: ApplicationFiled: January 10, 2002Publication date: September 12, 2002Applicant: Cabot Microelectronics CorporationInventors: Homer Chou, Joseph D. Hawkins, Renjie Zhou
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Patent number: 6409936Abstract: A composition and method of construction and use therefor in chemical-mechanical polishing (“CMP”) of one or more substrate assemblies is described. More particularly, a polishing solution comprising etchant, abrasive particles, and surfactant and methods of mixing to form and to dispense the polishing solution are described. One or more of the etchant, abrasive particles, and/or surfactant may comprise a liquid medium. Etchant, surfactant or abrasive particles may be premixed, mixed in-situ (“point of use mixing”), or any combination thereof. The surfactant may be ionic or nonionic. In particular, a polyoxyethylene may be used, and more particularly, a polyoxyethylene ester or ether may be used.Type: GrantFiled: February 16, 1999Date of Patent: June 25, 2002Assignee: Micron Technology, Inc.Inventors: Karl M. Robinson, Whonchee Lee
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Patent number: 6387188Abstract: A method of conditioning pads used in the polishing of semiconductor wafers containing copper circuitry. The method includes applying a treatment solution that contains a reactant for particulate copper-containing debris on the pad resulting from the copper circuitry. Preferably, the reactant is a carboxylic acid present in a concentration of from about 0.1 to about 10 weight percent in a solution. The pH of the solution may be adjusted to the range from about 1 to about 6 with a compatible base.Type: GrantFiled: March 3, 1999Date of Patent: May 14, 2002Assignee: SpeedFam-IPEC CorporationInventors: Thomas Laursen, Malcolm K. Grief, Krishna P. Murella, Sanjay Basak
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Patent number: 6361712Abstract: A composition for selective etching of oxides over a metal. The composition contains water, hydroxylammonium salt, carboxylic acid, a fluorine containing compound, and optionally, a base. The pH of the composition is about 2 to 6.Type: GrantFiled: October 15, 1999Date of Patent: March 26, 2002Assignee: Arch Specialty Chemicals, Inc.Inventors: Kenji Honda, Michelle Elderkin
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Patent number: 6350393Abstract: Chemical mechanical polishing compositions including an abrasive and cesium hydroxide and methods for polishing dielectric layers associated with integrated circuits using cesium hydroxide containing polishing compositions.Type: GrantFiled: November 4, 1999Date of Patent: February 26, 2002Assignee: Cabot Microelectronics CorporationInventors: Alicia F. Francis, Brian L. Mueller, James A. Dirksen, Paul M. Feeney
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Publication number: 20020017064Abstract: The present invention provides an LSI device polishing composition containing water, abrasive grains, an organic acid, and an oxidizing agent, and having a pH of 5.5-10.0 adjusted by an alkaline substance, the LSI device polishing composition being used for polishing a copper-containing metal wiring layer in which copper is deposited on an insulating film via barrier metal formed of Ta or TaN; and a method for producing LSI devices by use of the polishing composition. During polishing of a barrier metal such as Ta or TaN and a copper wiring layer, the rate of polishing Ta or TaN can be enhanced, to thereby prevent dishing and erosion.Type: ApplicationFiled: July 2, 2001Publication date: February 14, 2002Inventors: Yoshitomo Shimazu, Takanori Kido, Nobuo Uotani
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Patent number: 6331487Abstract: A method of removing polishing residue from a substrate includes placing the substrate in a pressure chamber, pressurizing the pressure chamber, and maintaining the supercritical fluid in contact with the substrate until the polishing residue is removed from the substrate. Following removal of the polishing residue from the substrate, the pressure chamber is flushed and vented.Type: GrantFiled: February 27, 2001Date of Patent: December 18, 2001Assignee: Tokyo Electron LimitedInventor: Robert Koch
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Patent number: 6303506Abstract: An aqueous slurry-less composition for chemical-mechanical-polishing of a silicon dioxide workpiece comprising: a cationic surfactant that is soluble and ionized at neutral to alkaline pH conditions, in which the cationic surfactant is present in an aqueous slurry-less composition in an amount less than its critical micelle concentration.Type: GrantFiled: September 30, 1999Date of Patent: October 16, 2001Assignee: Infineon Technologies AGInventors: Haruki Nojo, Ronald J. Schutz, Ravikumar Ramachandran
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Patent number: 6280652Abstract: An edge polishing composition for wafers, comprising water and silicon dioxide having an average particle size of from 70 to 2,500 nm.Type: GrantFiled: June 2, 1999Date of Patent: August 28, 2001Assignee: Fujimi IncorporatedInventors: Yutaka Inoue, Akihiro Kawase
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Patent number: 6277749Abstract: A processing solution containing hydrogen peroxide, hydracid fluoride salt, and water is used for pre-cleaning prior to a step of forming a gate oxide film 14 by subjecting a silicon wafer 1 to a heat treatment. Tetraalkyl ammonium fluoride, ammonium fluoride or the like is used as hydracid fluoride salt.Type: GrantFiled: September 9, 1999Date of Patent: August 21, 2001Assignee: Hiatchi, Ltd.Inventor: Michimasa Funabashi
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Patent number: 6277753Abstract: A method of removing Chemical Mechanical Polishing (CMP) residue from a semiconductor substrate is disclosed. The semiconductor substrate with the CMP residue on a surface is placed within a pressure chamber. The pressure chamber is then pressurized. Supercritical carbon dioxide and a solvent are introduced into the pressure chamber. The supercritical carbon dioxide and the chemical are maintained in contact with the semiconductor substrate until the CMP residue is removed from the semiconductor substrate. The pressure chamber is then flushed and vented.Type: GrantFiled: September 28, 1999Date of Patent: August 21, 2001Assignee: Supercritical Systems Inc.Inventors: William H. Mullee, Marc de Leeuwe, Glenn A. Roberson, Jr.
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Patent number: 6242351Abstract: The multistage process for the chemical-mechanical planarization (CMP) of Cu commences with forming a primary aqueous or non-aqueous (e.g., using alcohols and ketones as non-aqueous carriers) slurry from (i) between about 0 and 7 wt-% of an oxidizer, (ii) between 0 and 7 wt-% of one or more of a complexing agent or a passivating agent, (iii) between about 0 and 5 wt-% of a surfactant, (iv) between about 0.001 and 5 wt-% diamond particles having an average particle size not substantially above about 0.4 &mgr;m, and (v) an amount of a pH adjustment agent so that the aqueous slurry has a pH of between about 3 and 10, and advantageously about 5). The Cu of the semiconductor wafer then is subjected to CMP using the primary aqueous slurry and then is subjected to a cleaning operation. Next, a secondary aqueous slurry from (i) between about 0 and 7 wt-% of one or more a complexing agent or a passivating agent, (ii) between about 0 and 5 wt-% of a surfactant, (iii) between about 0.Type: GrantFiled: June 8, 2000Date of Patent: June 5, 2001Assignee: General Electric CompanyInventors: Yuzhuo Li, David Bruce Cerutti, Donald Joseph Buckley, Jr., Earl Royce Tyre, Jr., Jason J. Keleher, Richard J. Uriarte, Ferenc Horkay
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Patent number: 6238592Abstract: A family of working liquids useful in modifying exposed surfaces of wafers for semiconductor fabrication are provided along with methods of modifying exposed surfaces of wafers for semiconductor fabrication utilizing such a family of working liquids, and semiconductor wafers made according the foregoing process. The working liquid of the invention is a solution of initial components, the components comprising: an oxidizing agent; an ionic buffer; a passivating agent; a chelating agent selected from iminodiacetic acid and salts thereof; and water.Type: GrantFiled: March 10, 1999Date of Patent: May 29, 2001Assignee: 3M Innovative Properties CompanyInventors: L. Charles Hardy, Jennifer L. Trice
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Patent number: 6179989Abstract: The present invention relates to an improved oxygen sensor and particularly to oxygen sensors used as exhaust sensors in vehicles. The oxygen sensor, which has an improved lean-rich response time and operability at lower temperatures, has been chemically etched and electrically treated, or chemically etched with a non-hydrofluoric acid solution.Type: GrantFiled: August 13, 1999Date of Patent: January 30, 2001Assignee: General Motors CorporationInventors: Frederick Lincoln Kennard, III, Robert Gregory Fournier, William John La Barge, Carilee E. Cole, Earl Wayne Lankheet, Tie Wang
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Patent number: 6168725Abstract: The invention is an aluminum etchant and method for chemically milling aluminum from, according to a preferred embodiment, a copper-aluminum-copper tri-metal layer to form three-dimensional circuits. The tri-metal comprises copper circuit patterns present on opposing surfaces of an aluminum foil, one of the copper patterns being laminated on a substrate. The etchant comprises an aqueous solution of 60 to 500 g/l base selected from (a) sodium hydroxide, (b) potassium hydroxide, and (c) their mixture; and 30 to 500 g/l of an additive selected from nitrite salt, a borate salt, a bromate salt, or mixture of any of them. The method comprises contacting the tri-metal with the etchant at a temperature between 25 and 95° C. for a time sufficient to remove a desired amount of the aluminum layer and provide (rigid, flexible, or 3-dimensional) electronic circuitry which may contain multiple conductive circuit layers.Type: GrantFiled: December 22, 1997Date of Patent: January 2, 2001Assignee: Visteon Global Technologies, Inc.Inventors: Achyuta Achari, Mohan R. Paruchuri