Aluminum-palladium alloy for initiation of electroless plating
AssigneeAstarix Inc.
InventorMark Kellam
Life of this patent
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Abstract
Thin layers of aluminum and palladium are deposited and annealed to produce aluminum-palladium alloy. The surface of the alloy is exposed and treated with an aluminum enchant to produce a catalytic surface. The catalytic surface is used for electroless plating of nickel, providing excellent plating uniformity and adhesion, as well as a reduced plating induction time. Several variants of the basic method are shown.
Claims11
In a semiconductor integrated circuit fabrication process, a method for providing an electrical conductor to contact a substrate, said method comprising:
- depositing a first layer of catalytic material on said substrate, said catalytic material comprising palladium;
- depositing a second layer of base material on said first layer, said base material comprising aluminum;
- at least partly diffusing said second layer and said first layer to form an alloy layer;
- removing base material of said second layer remaining on said alloy layer;
- removing a portion of atoms of said base material from said alloy layer;
- wherein an active catalytic surface is formed substantially by palladium atoms which remain after removal of aluminum atoms;
- and
- depositing a conductive material at said active catalytic surface to form said electrical conductor;
- wherein said electrical conductor contacts said substrate in said semiconductor integrated circuit.
In a semiconductor integrated circuit fabrication process, a method for providing an electrical conductor to contact a substrate, said method comprising:
- depositing a first layer of base material on said substrate, said base material comprising aluminum;
- depositing a second layer of catalytic material on said first layer, said catalytic material comprising palladium;
- diffusing said first and second layers to form an alloy layer so that the surface of said formed alloy layer, which surface is distal from said substrate, contains aluminum atoms;
- and
- removing aluminum atoms from said alloy layer;
- wherein an active catalytic surface is formed substantially by palladium atoms which remain exposed along said active catalytic surface after removal of aluminum atoms;
- and
- depositing a conductive material at said active catalytic surface to form said electrical conductor;
- wherein said electrical conductor contacts said substrate in said semiconductor integrated circuit.
In a semiconductor integrated circuit fabrication process, a method for providing an electrical conductor to contact a substrate, said method comprising:
- forming an alloy layer of a catalytic material comprising palladium and a base material comprising aluminum on said substrate;
- forming a masking layer on said alloy layer;
- forming an opening in said masking layer using a first etchant;
- and
- removing a portion of the aluminum atoms from said alloy layer by exposing said alloy layer to a second etchant through said opening, said second etchant having a higher etch rate of aluminum than palladium;
- wherein said active catalytic surface is formed substantially by palladium atoms which remain after removal of aluminum atoms;
- and
- depositing a conductive material at said active catalytic surface to form said electrical conductor;
- wherein said electrical conductor contacts said substrate in said semiconductor integrated circuit.
Dependencies are inferred from the claim text.