초록 ▼

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

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. Pin holes through the three layers may cause, under the influence of a corrosive atmosphere, migration of ions up to the base layer but, due to the arrangement of electromotive potentials of the intermediate and the cover layer, will not extend further so that the corroded substrate material will, effectively, form a plug for the pin hole and prevent progression of corrosion.

대표청구항 ▼

A corrosion resistant semiconductor package sealing cover comprising a substrate (12) comprising an iron-based alloy (F15), or alloy 42; and only three layers electroplated sequentially on said substrate to impart corrosion resistance to said substrate, said only three layers comprising a base layer

A corrosion resistant semiconductor package sealing cover comprising a substrate (12) comprising an iron-based alloy (F15), or alloy 42; and only three layers electroplated sequentially on said substrate to impart corrosion resistance to said substrate, said only three layers comprising a base layer (14) electroplated on a substrate (12) and comprising a metal selected from the group consisting of gold, platinum, silver, palladium, or their alloys; a single intermediate layer (16) electroplated on the base layer (14) and comprising a nickel or nickel-based alloy; and a cover layer (18) electroplated on the intermediate layer (16) and comprising a metal selected from the group consisting of gold, platinum, silver, palladium, or their alloys.