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US 5,849,355 AGranted
Electroless copper plating
AssigneeAlliedSignal Inc.
InventorMichael R. McHenry
Life of this patent
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Abstract
An optimized electroless copper plating technique suitable for plating electroless copper upon ceramics.
Claims3
A process for electroless copper coating on a substrate, comprising the steps of:
- cleaning the substrate
- alkaline cleaning and conditioning for a dwell time of about 4.5 to 5.5 minutes;
- rinsing with Reverse Osmosis water;
- preconditioning said substrate in a stannous chloride solution from about 0.75 to about 1.5 minutes;
- treating with a tin-palladium colloid;
- postactivating with a solution to remove tin from the tin-palladium colloid from about 2.75 to about 3.25 minutes;
- and
- applying electroless copper in solution, which solution has been used less than about one week.
5 more elements
A process for optimizing an electroless copper coating process so as to maximize overall adhesion and coverage of the electroless copper onto a substrate, wherein the electroless copper coating process comprises the steps of:
- initial abrasive cleaning the substrate, alcohol rinsing the substrate, immersing the substrate in an alkaline cleaning and conditioning solution, rinsing the substrate with reverse osmosis water, immersing the substrate in a preconditioning solution of stannous chloride, treating the substrate with a tin-palladium colloid, immersing the substrate in a postactivating solution to remove tin from the tin-palladium colloid, and applying electroless copper in solution;
- the optimizing process comprising the steps of:
- adjusting the time in which the substrate is in the alkaline cleaning and conditioning solution so as to maximize adhesion and coverage of the resulting electroless copper on a substrate;
- adjusting the time in which the substrate is in the postactivating solution so as to maximize adhesion and coverage of the resulting electroless copper on a substrate;
- and
- adjusting the age of the electroless copper bath so as to maximize adhesion and coverage of the resulting electroless copper on a substrate.
3 more elements
Dependencies are inferred from the claim text.