Electroless/electrolytic methods for the preparation of metallized ceramic substrates
OwnerStojan Djokic, Ross Lepard +1inventors
InventorsStojan Djokic, Ross Lepard, Robert Roy
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Abstract
An improved process for the preparation of metallized ceramic substrates having a metal layer ranging from ten to two hundred microns in thickness, and having enhanced adhesion strength is provided. The process involves, in combination, a novel method for conditioning the ceramic substrate and the application of a thin intermediate layer of electrolessly and optionally, electrolytically, deposited metal prior to electrolytic metal deposition of an outer metallized layer.
Claims20
A process for the production of a metalized ceramic substrate which comprises:
- a) cleaning said ceramic substrate with an organic solvent;
- b) etching said cleaned substrate at ambient temperature with an aqueous alkaline solution;
- c) rinsing said etched substrate in water to remove substantially all the alkaline solution;
- d) heat treating said etched substrate of step c) at a temperature effective to pyrolyse any residual organic solvent;
- e) subjecting said heat treated substrate to a second alkaline etch at ambient temperature to remove any alkaline soluble impurities formed during said heat treatment step;
- f) rinsing said etched substrate of step e) in water to remove substantially all the alkaline solution;
- g) electrolessly depositing a metal selected from the group consisting of nickel, silver, gold, cobalt, palladium and platinum on the substrate of step f) to form an intermediate thin metal layer;
- and
- h) electrodepositing a metal from an aqueous solution, said metal selected from the group consisting of nickel, copper, silver, gold, cobalt, palladiuim and platinum, or an alloy thereof with an element selected from the group consisting of phosphorous, boron, tungsten and molybdenum upon said intermediate thin metal layer.
A method for conditioning a ceramic substrate prior to metal deposition thereon which comprises:
- cleaning said ceramic substrate with an organic solvent;
- etching said cleaned substrate at ambient temperature using an aqueous alkaline solution;
- rinsing said etched substrate in water to remove substantially all the alkaline solution;
- heat treating said etched substrate at a temperature effective to pyrolyse any residual organic impurities;
- subjecting said heat treated substrate to a second alkaline etch at ambient temperature to remove any alkaline soluble impurities formed during said heat treatment step;
- and rinsing said etched substrate from the second alkaline etch in water to remove substantially all the alkaline solution.
A method for producing a thin-filmed metallized ceramic substrate which comprises:
- cleaning said ceramic substrate with an organic solvent;
- etching said cleaned substrate at ambient temperature with an aqueous alkaline solution;
- rinsing said etched substrate in water to remove substantially all the alkaline solution. Heat treating said etched substrate at a temperature effective to pyrolyse any residual organic impurities;
- subjecting said heat treated substrate to a second alkaline etch at ambient temperature to remove any alkaline soluble impurities formed during said heat treatment step;
- sensitizing the subjected substrate for electroless deposition;
- forming palladium active sites on said sensitized substrate;
- electrolessly depositing a metal selected from the group consisting of nickel, silver, gold, copper, cobalt, platinum and palladium on the formed substrate;
- and electrolytically depositing a metal selected from the group consisting of nickel, silver, gold, copper cobalt, palladium and platinum or an alloy thereof with an element selected from the group consisting of phosphorus, boron, tungsten or molybdenum on the electroless substrate to thereby provide a thin-filmed metallized ceramic substrate.
Dependencies are inferred from the claim text.