W.c. Heraeus Gmbh

W.c. Heraeus Gmbh & Co Kg

W. C. Hereaus Gmbh & Co. Kg

Thomas Frey

Gunter Herklotz

G&uuml;nter Herklotz

Frank Kr&uuml;ger

Thomas Giesel

Bernd Gehlert

G Unter Herklotz

Wolfgang Hempel

Heinz F&ouml;rderer

Heinz Forderer

Otto Camus

A support structure is provided for holding open lumina, the support structure having a stainless steel substrate and a platinum layer forming the surface of the structure. The structure has at least one gold layer arranged between the substrate and the platinum layer. The platinum layer is preferably applied with a pulsed current with current reversal, in order to avoid or reduce brittleness occurring by absorption of hydrogen during galvanic deposition of platinum. Such a support structure (stent) substantially withstands the high mechanical stresses, particularly bending and torsional forces that occur during application, without the formation of significant tears in the platinum layer.

Support structure

A method for the manufacture of a leadless substrate with a basic body made of copper or copper base alloy, a solder layer applied to at least one portion of the basic body and made of metals belonging to the group of gold, gold alloy, silver, silver alloy, palladium, and palladium alloy, as well as an intermediate layer arranged between the basic body and the solder layer and made of nickel or nickel alloy, wherein the solder layer consists of at least two separate layers made of different metals and wherein the intermediate layer and the separate layers are deposited by electroplating, characterized in that at least one separate layer is made of silver or silver alloy.

Method for producing a lead-free substrate

Aqueous ammoniacal baths containing polyamines and mercaptoalkane carboxylic acids and/or mercaptoalkane sulfonic acids for the electrodeposition of palladium-silver alloys are provided, which are particularly suited as electrical contacts. The baths have very good stability and permit the deposition of alloys with a silver content up to approximately 99 weight %.

Bath for the electrodeposition of palladium-silver alloys

Silver-tin alloys can be deposited by the galvanic method from a cyanide-free bath which is prepared using silver as the nitrate or diammine complex, tin as the soluble tin(II) or tin(IV) compound and mercaptoalkane-carboxylic acids and -sulfonic acids, Uniform and adhering coatings of silver-tin alloys with a silver content of approximately 20 to 99 weight % can be deposited from said bath. Silver-tin alloys are electrodeposited from said bath at a pH of 0 to 14 and a current density of 0.1 to 10 A/dm.sup.2.

Electroplating bath for the electrodeposition of silver-tin alloys

Lead frames completely surface-plated with palladium have a nickel-phosphorus or copper-tin layer between the base element, made for example of copper, and the palladium layer. Such lead frames exhibit good bondability and good solderability without tinning.

Lead frame for integrated circuits

A thin galvanically deposited gold-containing surface layer is backed by a support layer containing a palladium alloy and having a thickness between 0.05 .mu.m and 0.5 .mu.m. In a preferred embodiment the surface layer and the support layer have a combined thickness of less than 0.5 .mu.m.

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Hanau, Germany

Thomas Frey