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AssigneeSiemens Aktiengesellschaft
InventorsJacky Vanhumbeeck, Hubert De Steur, Guido Heyneman, Chris Vandenbossche
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A control apparatus for automatically controlling at least the concentration of copper-ions, hydroxyl-ions and formaldehyde-ions in an electroless copper plating bath and independently analyzing, displaying and replenishing the concentration of each such ions whereby a sample for each of the ions is discontinuously removed from the plating bath and diluted with a specific amount of water and, independently of one another, the copper-ion concentration is colorimetrically analyzed, displayed and replenished as needed, the hydroxyl-ion concentration is potentiometrically analyzed, displayed and replenished as needed and the formaldehyde-ion concentration is amperometrically analyzed, displayed and replenished as needed.
In an apparatus for controlling the concentration of at least main consumable components of an electroless copper plating bath having main components comprised of an aqueous solution of copper ions, an aqueous solution of sodium hydroxide and an aqueous solution of formaldehyde, to predetermined relatively constant values, whereby copper ion concentration is colorimetrically identified and the sodium hydroxide and formaldehyde solution concentrations are titrimetrically identified and appropriate signals are sent to a source of such components to add a select amount of each component to said bath until the concentration of each component is at said predetermined relatively constant value, the improvement comprising wherein said apparatus comprises, in combination:
A method of automatically controlling the concentration of at least main components in an electroless copper plating bath having main components comprised of an aqueous solution of copper ions, an aqueous solution of sodium hydroxide and an aqueous solution of formaldehyde so that said concentration remains relatively constant throughout the operation of said bath, comprising the steps of:
An apparatus for controlling the concentration of main components in an electroless copper plating bath having main components comprised of an acqueous solution of copper ions, an aqueous solution of sodium hydroxide and an aqueous solution of formaldehyde, comprising, in combination:
Dependencies are inferred from the claim text.