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CONDUCTIVE PALLADIUM SULFIDE

The Crimson™ Direct Plate Process

Crimson™ Trademark of Dow Chemical

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PREPARATION

1. Palladium-tin colloidal particles have a Pd-rich core and are charge-stabilized with negatively charged tin chloride species.

2. Palladium-Tin colloid is adsorbed onto substrate pretreated with cationic surfactant.

3. Tin rinsed off.

4. Substrate is exposed to alkaline solution of sodium sulfide, producing PdS.

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• Crimson™ Direct Plate Process

• Used to electroplate thru-holes in printed circuit boards

• Adsorbed PdS nanoparticles on epoxy substrate permits immediate copper electroplating.

APPLICATION

Crimson™ Trademark of Dow Chemical

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• XAS, XPS and Extended X-ray Absorption Fine Structure (EXAFS) research is published:

• A Palladium Sulfide Catalyst for Electrolytic Plating. Bladon, John J. et al, Electrochem. Soc. (1996), 143(4), 1206-13

ESTABLISHING COMPOSITION AND STRUCTURE

MEASURING PARTICLE SIZE USING

ATOMIC FORCE MICROSCOPY

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PREPARATION OF SAMPLE

• Atomically flat pyrolytic graphite is processed through Crimson™ Direct Plate.

• Exposure time is adjusted to avoid multilayer adsorption of colloid.

• Sample is rinsed and air dried.

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Surface view of PdS nanoparticles

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Diameter of PdS nanoparticlesis about 5 nm

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Isometric view of PdS nanoparticles

PATENTS ON CRIMSON™ DIRECT PLATE PROCESS

• Electroplating Process. Bladon, John J., (Shipley Co). April 24, 1990; US 4,919,768.

• Method for electroplating nonconductors. Bladon, John J.; Robinson, John N.; Rousseau, Michael. (Shipley Co). April 28, 1990; US 4,952,286.

• Electroplating process. Bladon, John J., (Shipley Co). April 16, 1991; US 5,007,990.

• Printed Circuit Board. Bladon, John J., (Shipley Co). May 21 1991; US 5,017,742.

• Electroplating Process and Composition. Bladon, John J., (Shipley Co). May 4, 1993; US 5,207,888.

• Spray Parameters for Horizontal Processing. Bladon, John J.; Colangelo, Carl; Robinson, John; Rousseau, Michael. (Rohm and Haas). Filed August 9, 1993; US 5,374,346.

• Electroplating Process and Composition. Bladon, John J., (Shipley Co). January 4, 1994; US 5,276,290.

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