Abstract: To simplify manufacture of plated metal parts with high corrosion resistance especially suitable for use as sealing lids or cover elements for semiconductor packages, a substrate of Kovar, or Alloy 42, which are nickel-containing iron alloys, are electroplated with a base layer of a metal having an electromotive potential high with respect to that of the substrate, over which an intermediate layer is electroplated, which intermediate layer (16) has an electromotive potential which is low with respect to the base layer, and over that a cover layer (18) is plated which has an electromotive potential similar to that of the base layer. Suitable metals are gold-nickel-gold combinations, in which the gold layers should be over 10 microinches thick, preferably and in order to meet MIL-STD 883C, about 25 microinches thick. The intermediate layer (16), if of nickel, has an electromotive potential which is at the negative side of the electromotive series.

Abstract: Plated metal parts, such as sealing lids for semiconductor packages, in which an iron-based alloy layer is electroplated with a first layer of nickel, a first layer of gold is electroplated on the first nickel layer, a second layer of nickel is electroplated onto the first gold layer and a second layer of gold is electroplated onto the second layer of nickel. The resultant plated parts exhibit higher salt atmosphere corrosion resistance than parts plated with a single nickel-gold set. Other metals can be used as the plating layers.

Abstract: Plated metal parts, such as sealing lids for semiconductor packages, in which an iron-based alloy layer is electroplated with a first layer of nickel, a first layer of gold is electroplated on the first nickel layer, a second layer of nickel is electroplated onto the first gold layer and a second layer of gold is electroplated onto the second layer of nickel. The resultant plated parts exhibit higher salt atmosphere corrosion resistance than parts plated with a single nickel-gold set. Other metals can be used as the plating layers.

Abstract: A hermetic sealing-cover unit for a container for semiconductor devices is fabricated by applying to the cover a solution of a thermosetting plastic material in a drying solvent to form a thin plastic coating on the cover. The solution preferably is a 10% concentration by weight of epoxy resin in a solvent comprising a mixture of methanol, ethylene dichloride, and dioxane in the ratio of 50:35:15. The cover element is of a material impervious to moisture and air, preferably a material of the group which includes metal, glass, quartz, and ceramic. A sealing ring is formed of substantially chemically unreacted thermosetting plastic material, preferably the same as the plastic material of the cover coating, and is of a size substantially to register with the periphery of the cover. The ring is then pressed into engagement with the plastic coating on the cover at ambient temperature, while the coating is still tacky, and the drying of the coating on the cover is completed to adhere the ring to the cover.