Seed Layers for Electroplated Interconnects

1 . A method for depositing two or more seed layers for electroplating metallic interconnects over a substrate, the substrate having a patterned insulating layer which includes at least one opening and a field surrounding the at least one opening, the at least one opening having top corners, sidewalls, and bottom, the field and the at least one opening being ready for depositing one or more seed layers, and the method comprising:

depositing a continuous seed layer over the sidewalls and bottom of the at least one opening using a first set of deposition parameters; and

depositing a second seed layer over the continuous seed layer using a second set of deposition parameters, wherein:

(i) the second set of deposition parameters includes at least one deposition parameter which is different from any of the parameters in the first set of deposition parameters, or the second set of deposition parameters includes at least one deposition parameter whose value is different in the two sets of deposition parameters, (ii) the continuous and second seed layers being sufficiently thick over the field to enable uniform electroplating across the substrate, and (iii) after depositing the seed layers, there is sufficient room for electroplating inside the at least one opening.

2 . The method of claim 1 , wherein: (i) the second seed layer comprises a physical vapor deposited (PVD) seed layer, (ii) at least one of the seed layers comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals, and (iii) the thickness of the continuous seed layer is less than about 250 Å over the field.

3 . The method of claim 2 , wherein: (i) the second seed layer having no substantial overhangs sealing or pinching-off the top corners of the at least one opening, and (ii) the thickness of the continuous seed layer is less than about 200 Å over the field.

4 . The method of claim 3 , wherein: (i) the at least one opening has a width of less than about 0.10 μm, (ii) the thickness of the continuous seed layer over the field is less than about 100 Å, and (iii) the thickness of the PVD seed layer over the field is from about 100 Å to about 3,000 Å.

5 . The method of claim 3 wherein the thickness of the continuous seed layer over the field is less than about 100 Å.

6 . The method of claim 1 wherein the continuous seed layer is deposited by a chemical vapor deposition (CVD) technique or by an electroless deposition technique.

7 . The method of claim 6 , wherein: (i) the continuous seed layer comprises a CVD seed layer, and (ii) the second seed layer comprises a PVD seed layer.

8 . The method of claim 7 , wherein (i) the thickness of the CVD seed layer is less than about 250 Å over the field, and (ii) at least one of the seed layers comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals.

9 . The method of claim 8 wherein: (i) the second seed layer having no substantial overhangs sealing or pinching-off the top corners of the at least one opening, and (ii) the thickness of the CVD seed layer is less than about 200 Å over the field.

10 . The method of claim 9 , wherein: (i) the at least one opening has a width of less than about 0.10 m, (ii) the thickness of the CVD seed layer over the field is less than about 100 Å, and (iii) the thickness of the PVD seed layer over the field is from about 100 Å to about 3,000 Å.

11 . The method of claim 1 further comprising depositing at least one additional seed layer over the second seed layer prior to electroplating.

12 . The method of claim 11 wherein said depositing at least one additional seed layer comprises using a conformal deposition technique.

13 . The method of claim 7 further comprising depositing at least one additional seed layer over the second seed layer prior to electroplating.

14 . The method of claim 13 wherein said depositing at least one additional seed layer comprises using a conformal deposition technique.

15 . The method of claim 11 wherein the continuous seed layer comprises a CVD seed layer, the second seed layer comprises a PVD seed layer, and the at least one additional seed layer comprises a CVD seed layer.

16 . The method of claim 1 further comprising depositing at least one additional seed layer prior to the deposition of the continuous seed layer.

17 . The method of claim 7 further comprising depositing at least one additional PVD seed layer prior to the deposition of the CVD seed layer.

18 . The method of claim 1 , wherein the continuous seed layer comprises a first CVD seed layer deposited using a first set of deposition parameters, and the second seed layer comprises a second CVD seed layer deposited using a second set of deposition parameters, and wherein the second set of deposition parameters includes at least one deposition parameter whose value is different in the two sets of deposition parameters.

19 . The method of claim 18 wherein at least one of the seed layers comprises a material selected from a group consisting of Cu, Ag, or alloys comprising one or more of these metals.

20 . The method of claim 19 wherein the thickness of the first CVD seed layer is more uniform than the thickness of the second CVD seed layer over the sidewall surfaces of the at least one opening.

21 . The method of claim 19 wherein the thickness of the first CVD seed layer is less uniform than the thickness of the second CVD seed layer over the sidewall surfaces of the at least one opening.

22 . The method of claim 19 wherein the first CVD seed layer and the second CVD seed layer are deposited in the same CVD chamber.

23 . The method of claim 19 wherein the first CVD seed layer is deposited in one CVD chamber, and the second CVD seed layer is deposited in another CVD chamber.

24 . The method of claim 19 wherein at least one of said CVD seed layers has a thickness of less than about 100 Å over the field.