Selective metal deposition over dielectric layers
Selective deposition of metal over dielectric layers in a manner that minimizes or eliminates keyhole formation is provided. According to one embodiment, a dielectric target layer is formed over a substrate layer, wherein the target layer may be configured to allow conformal metal deposition, and a dielectric second layer is formed over the target layer, wherein the second layer may be configured to allow bottom-up metal deposition. An opening may then be formed in the second layer and metal may be selectively deposited over the substrate layer.
1. A method of performing selective electroless plating comprising:
forming a dielectric target layer over a conductive substrate layer, said target layer configured to allow conformal metal deposition;
forming a dielectric second layer over said target layer, said second layer configured to allow bottom-up metal deposition, the dielectric second layer being chlorine poor relative to the dielectric target layer;
forming an opening in said second layer; and
performing selective electroless plating over said target and conductive substrate layer.
2. The method of claim 1 wherein the dielectric target layer comprises an oxide.
3. The method of claim 1 wherein the dielectric target layer is hydrogen rich.
4. The method of claim 1 wherein the dielectric target layer is chlorine rich.
5. The method of claim 1 wherein the dielectric target layer is hydrogen rich and chlorine rich.
6. The method of claim 1 wherein the dielectric second layer is formed at a temperature of less than 600° C.
7. The method of claim 1 wherein the dielectric second layer is hydrogen poor relative to the dielectric target layer.
8. The method of claim 1 wherein the forming the opening exposes a contact on the substrate layer.
9. The method of claim 1 wherein the forming the opening comprises forming a trench.
10. The method of claim 1 wherein the electroless plating comprises nickel-phosphorus electroless plating.
11. The method of claim 1 wherein the electroless plating comprises electroless plating of a metal or alloy comprising one or more members of the group consisting of nickel, gold, silver, copper, cobalt, palladium, platinum, rhodium, iron, tungsten, thallium, and boron.
12. A method of performing selective electroless plating to a damascene structure comprising:
forming a semiconductor substrate;
forming a dielectric target layer over a substrate layer, said target layer configured to allow conformal metal deposition;
forming a dielectric second layer over said target layer, said second layer configured to allow bottom-up metal deposition, the dielectric second layer having a lower chlorine content relative to the dielectric target layer;
forming an opening in said second layer; and
performing selective electroless plating over said substrate layer.
13. The method of claim 12 wherein the dielectric target layer comprises hydrogen rich oxide, hydrogen rich silicon oxynitride, hydrogen rich silicon nitride or a hydrogen rich low k dielectric.
14. The method of claim 12 wherein the dielectric target layer has a hydrogen content of approximately 6%.
15. The method of claim 12 wherein the dielectric second layer is selected from the group consisting of doped or undoped silicon dioxide, phosphosilicate glass, tetraethyl orthosilicate, silicon oxynitride and non-conductive metal nitrides, and wherein the dielectric second layer has a lower hydrogen content relative to the dielectric target layer.