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AssigneeMitsui Mining & Smelting Co., Ltd.
InventorsNobuyuki Imada, Yutaka Hirasawa, Yasuji Hara, Naoya Matsushita
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A process for producing an electrodeposited copper foil, comprising electrodepositing a copper foil from an electrolyte containing copper sulfate dissolved therein, in which said electrolyte contains a small amount of lead (Pb) ions, which comprises adding a salt of a metal of Group IIA of the periodic table to the electrolyte in an amount of 10 to 150 mols per mol of lead (Pb) ions contained in the electrolyte so that the lead (Pb) ions contained in the electrolyte react with the metal of Group IIA of the periodic table to thereby form an insoluble composite substance to precipitate, the insoluble composite substance followed by removing it from the electrolyte and forming an electrodeposited copper foil in the electrolyte having the lead (Pb) ions removed therefrom.
A process for producing an electrodeposited copper foil from an electrolyte containing copper sulfate dissolved therein, in which said electrolyte contains a small amount of lead (Pb) ions, said process comprising the steps of adding a salt of a metal of Group IIA of the periodic table to the electrolyte in an amount of 10 to 150 mols per mol of lead (Pb) ions contained in the electrolyte, reacting the lead (Pb) ions contained in the electrolyte with the metal of Group IIA of the periodic table to thereby form an insoluble composite substance, precipitating and removing said insoluble composite substance from the electrolyte and electrodepositing a copper foil from the electrolyte having the lead (Pb) ions removed therefrom.
A process for producing an electrodeposited copper foil from an electrolyte containing copper sulfate dissolved therein, in which said electrolyte contains a small amount of lead (Pb) ions, and further contains chloride ions in a concentration of 0.1 to 5.0 mg/liter, said process comprising the steps of adding a salt of a metal of Group IIA of the periodic table to the electrolyte in an amount of 10 to 150 mols per mol of lead (Pb) ions contained in the electrolyte, reacting the lead (Pb) ions contained in the electrolyte with the metal of Group IIA of the periodic table to thereby form an insoluble composite substance, precipitating and removing said insoluble composite substance from the electrolyte and electrodepositing a copper foil from the electrolyte having the lead (Pb) ions removed therefrom.
A process for producing an electrodeposited copper foil from an electrolyte containing copper sulfate dissolved therein, in which said electrolyte contains a small amount of lead (Pb) ions and further contains chloride ions in a concentration of 0.1 to 5.0 mg/liter, said process comprising the steps of adding strontium carbonate to the electrolyte in an amount of 10 to 150 mols per mol of lead (Pb) ions contained in the electrolyte, reacting the lead (Pb) ions contained in the electrolyte with the strontium to thereby form an insoluble composite substance, precipitating and removing said insoluble composite substance from the electrolyte and electrodepositing a copper foil from the electrolyte having the lead (Pb) ions removed therefrom.
A process for producing an electrodeposited copper foil from an electrolyte containing copper sulfate dissolved therein, in which said electrolyte contains a small amount of lead (Pb) ions and further contains chloride ions in a concentration of 0.1 to 5.0 mg/liter, said process comprising the steps of adding calcium carbonate and/or barium carbonate to the electrolyte in an amount of 10 to 150 mols per mol of lead (Pb) ions contained in the electrolyte, reacting the lead (Pb) ions contained in the electrolyte with the calcium and/or barium to thereby form an insoluble composite substance, precipitating and removing said insoluble composite substance from the electrolyte and eletrodepositing a copper foil from the electrolyte having the lead (Pb) ions removed therefrom.
Dependencies are inferred from the claim text.
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Electroforming: wires; Strips; Foils
From solutions: of copper
Processes for servicing or operating cells for electrolytic coating: process control or regulation
Details: use of materials for the conductive, e.g. metallic pattern
Term ended 8 Jun 2020 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to a process for producing an electrodeposited copper foil, an electrodeposited copper foil obtained by such a process, a copper-clad laminate for which the electrodeposited copper foil is used and a printed wiring board. More particularly, the present invention relates to a producing process of an electrodeposited copper foil in which lead (Pb) ions contained as impurities in the electrolyte are removed to thereby prevent codeposition of fine particles (fine powder) of Pb and/or Pb compounds (mainly lead oxides); and an electrodeposited copper foil produced by the process, which is substantially free from fine particles of Pb and/or Pb compounds. The present invention further relates to a copper-clad laminate produced using the electrodeposited copper foil, which comprises a substrate having at least one side thereof laminated with the electrodeposited copper foil; and a printed wiring board produced using the electrodeposited copper foil.
In the continuous production of an electrodeposited copper foil, it is common practice to arrange a cylindrical drum as a cathode and, opposite thereto, an insoluble anode in an electrolyte in which a copper material such as copper sulfate is dissolved and to carry out electrolysis so that copper is electrodeposited on the surface of the cylindrical drum.
In recent years, electronic equipment is being miniaturized and densified, and accordingly circuit widths and circuit spacings of printed wiring boards used in such electronic equipment are being reduced. The use of a thin electrodeposited copper foil with low surface roughness (profile) is desired in accordance with the above reduction of circuit widths and circuit spacings.
FIG. 1 shows a schematic view of an embodiment of process flow for producing an electrodeposited copper foil according to the present invention.
Process for Producing Electrodeposited Copper Foil and Electrodeposited Copper Foil
In the process for producing an electrodeposited copper foil according to the present invention, referring to FIG. 1, use is made of an apparatus comprising electroforming cell 1 filled with an electrolyte containing copper sulfate dissolved therein, in which cathode drum la whose surface is generally made of Ti or Ti alloy is immersed and rotatably arranged. Referring further to FIG. 1, the apparatus for use in the process for producing an electrodeposited copper foil according to the present invention is generally equipped with electroforming cell 1, spent solution tank 2, copper dissolving and circulating tank 3, supply solution storage tank 4, additives tank 5, filter 6, roll winder 7, copper dissolving tower 8, dissolving circulation pump P1 and solution supply pump P2.
The electrolyte to be fed into the electroforming cell 1 is prepared by feeding copper raw materials into the copper dissolving tower 8 and dissolving the copper raw materials in a spent solution returned from the spent solution tank 2 to the copper dissolving tower 8. The spent solution used herein is the electrolyte having overflowed from the electroforming cell 1, which is used after recovering the overflowed electrolyte in the spent solution tank 2 and then transporting it to the dissolving and circulating tank 3.