Metal nitride barrier layer and electroplating seed layer with the same metal as the metal nitride layer
First Claim
1. A protective barrier layer interposed between a highly conducting metallic element in an integrated circuit and an interlevel dielectric, the barrier layer comprising a metallic nitride sub-layer having a nitrogen content graded generally linearly from a first concentration adjacent to the interlevel dielectric to about zero adjacent to the metallic element.
7 Assignments
0 Petitions
Accused Products
Abstract
A barrier layer material and method of forming the same is disclosed. The method includes depositing a graded metal nitride layer in a single deposition chamber, with a high nitrogen content at a lower surface and a high metal content at an upper surface. In the illustrated embodiment, a metal nitride with a 1:1 nitrogen-to-metal ratio is initially deposited into a deep void, such as a via or trench, by reactive sputtering of a metal target in nitrogen atmosphere. After an initial thickness is deposited, flow of nitrogen source gas is reduced and sputtering continues, producing a metal nitride with a graded nitrogen content. After the nitrogen is stopped, deposition continues, resulting in a substantially pure metal top layer. This three-stage layer includes a highly conductive top layer, upon which copper can be directly electroplated without a separate seed layer deposition. Advantageously, native oxide on the top metal surface can be cleaned in situ by reversing polarity in the electroplating solution just prior to plating.
43 Citations
22 Claims
- 1. A protective barrier layer interposed between a highly conducting metallic element in an integrated circuit and an interlevel dielectric, the barrier layer comprising a metallic nitride sub-layer having a nitrogen content graded generally linearly from a first concentration adjacent to the interlevel dielectric to about zero adjacent to the metallic element.
-
11. A protective barrier layer interposed between a highly conducting metallic element in an integrated circuit and an interlevel dielectric, the barrier layer comprising a metallic nitride sub-layer having a nitrogen content graded generally in a plurality of steps from a first concentration adjacent to the interlevel dielectric to about zero adjacent to the metallic element.
-
12. A protective barrier layer interposed between a highly conducting metallic element in an integrated circuit and an interlevel dielectric, the barrier layer comprising a metallic nitride sub-layer having a metal content graded in a generally exponential manner from a first concentration adjacent to the interlevel dielectric to a much higher concentration adjacent to the metallic element.
-
13. An integrated circuit comprising a wiring structure within an opening formed in an insulating layer, the wiring structure comprising:
-
a barrier portion including a first metal nitride sub-layer and a second metal nitride sub-layer contacting the first metal nitride;
a metal seed layer directly overlying the second metal nitride sub-layer of the barrier portion, the metal seed layer comprising the same metal as the metal nitride sub-layer, wherein the second metal nitride sub-layer has a nitrogen content varying generally linearly or in a plurality of steps from a first concentration at the first metal nitride sub-layer to the metal seed layer having substantially zero nitrogen content; and
a copper layer directly overlying the metal seed layer. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
-
Specification