Interconnection structure and method for fabricating the same
An interconnection structure is provided to include an interlayer dielectric (ILD) layer that is disposed over a substrate, a metal via that is disposed in the ILD layer, and a metal wire that is disposed over the metal via in the ILD layer and that is electrically connected to the metal via. The ILD layer includes silicon carbon nitride.
1 . An interconnection structure, comprising:
a silicon carbon nitride (SiCN) layer disposed over a substrate, wherein an atomic ratio among silicon, carbon and nitrogen in the SiCN layer is configured such that the SiCN layer has a dielectric constant ranging from 2.5 to 3.6;
a metal via that is disposed in the SiCN layer; and
a metal wire that is disposed over the metal via in the SiCN layer, and that is electrically connected to the metal via.
2 . The interconnection structure according to claim 1 , further comprising a conductive cap feature disposed over the metal wire, and an etch stop layer that is disposed over the SiCN layer and the conductive cap feature, wherein a material of a portion of the etch stop layer that is in contact with a top surface of the conductive cap feature is same as a material of a portion of the etch stop layer that is in contact with a lateral surface of the conductive cap feature.
3 . The interconnection structure according to claim 2 , wherein the conductive cap feature includes a graphene layer that is in contact with the etch stop layer, and a material of a portion of the etch stop layer that is in contact with a top surface of the graphene layer is same as a material of a portion of the etch stop layer that is in contact with a lateral surface of the graphene layer.
4 . The interconnection structure according to claim 2 ,
wherein the etch stop layer includes a layer of silicon carbon nitride and a layer of aluminum oxide that are stacked together.
5 . The interconnection structure according to claim 2 ,
wherein the etch stop layer includes a layer of silicon carbon nitride and a layer of aluminum oxycarbide that are stacked together.
6 . The interconnection structure according to claim 2 , wherein the etch stop layer is a layer of SiCN, and an atomic ratio among silicon, carbon and nitrogen in the etch stop layer is same as the atomic ratio among silicon, carbon and nitrogen in the SiCN layer.
7 . An interconnection structure, comprising:
a metal via that is disposed over a substrate;
a metal wire that is disposed over the metal via, wherein the metal via electrically connects the metal wire to a conductive feature that is disposed in the substrate;
a silicon carbon nitride (SiCN) layer that surrounds the metal via and the metal wire; and
a hermetic etch stop layer disposed over the SiCN layer.
8 . The interconnection structure according to claim 7 , further comprising a conductive cap feature disposed over the metal wire and in the hermetic etch stop layer, wherein the conductive cap feature includes a graphene layer that is covered and surrounded by the hermetic etch stop layer.
9 . The interconnection structure according to claim 8 ,
wherein the hermetic etch stop layer includes a layer of silicon carbon nitride and multiple layers of different aluminum-based materials.
10 . The interconnection structure according to claim 8 , wherein the hermetic etch stop layer is a layer of SiCN, and an atomic ratio among silicon, carbon and nitrogen in the hermetic etch stop layer is same as an atomic ratio among silicon, carbon and nitrogen in the SiCN layer.
11 . An interconnection structure, comprising:
a first interconnection metal feature disposed over a substrate;
a first silicon carbon nitride (SiCN) layer surrounding the first interconnection metal feature;
a conductive cap feature disposed over the first interconnection metal feature, and including graphene;
an etch stop layer disposed over the first dielectric layer, the first interconnection metal feature, and the conductive cap feature;
a second interconnection metal feature disposed over and electrically connected to the first interconnection metal feature, and extending through the etch stop layer and the conductive cap feature; and
a second SiCN layer surrounding the second interconnection metal feature.
12 . The interconnection structure according to claim 11 , wherein the etch stop layer is a layer of silicon carbon nitride, and an atomic ratio among silicon, carbon and nitrogen in the first SiCN layer is same as an atomic ratio among silicon, carbon and nitrogen in the etch stop layer.
13 . The interconnection structure according to claim 1 , wherein the atomic ratio among silicon, carbon and nitrogen in the SiCN layer is configured such that the SiCN layer has a thermal conductivity ranging from 0.6 W/(m·K) to about 1.3 W/(m·K).
14 . The interconnection structure according to claim 1 , further comprising a liner layer sandwiched between the SiCN layer and the metal wire and between the metal wire and the metal via.
15 . The interconnection structure according to claim 14 , further comprising another liner layer sandwiched between the SiCN layer and the metal via.
16 . The interconnection structure according to claim 15 , wherein the substrate includes an interlayer dielectric (ILD) layer, another metal wire disposed in the ILD layer, and another conductive cap feature disposed over said another metal wire, and
wherein said another liner layer extends through said another conductive cap feature and is in contact with said another metal wire.
17 . The interconnection structure according to claim 1 , further comprising an air gap disposed in the SiCN layer, wherein the air gap has an upper portion adjacent to the metal wire, and a lower portion adjacent to the metal via.
18 . The interconnection structure according to claim 17 , wherein the lower portion of the air gap is wider than the upper portion of the air gap.
19 . The interconnection structure according to claim 8 , wherein an atomic ratio among silicon, carbon and nitrogen in the SiCN layer is configured such that the SiCN layer has a thermal conductivity ranging from 0.6 W/(m·K) to about 1.3 W/(m·K), and a dielectric constant ranging from 2.5 to 3.6.
20 . The interconnection structure according to claim 8 , further comprising:
another metal via disposed in the SiCN layer;
another metal wire disposed over the metal via and in the SiCN layer; and
an air gap disposed in the SiCN layer, and having an upper portion disposed between and adjacent to the metal wire and said another metal wire, and a lower portion disposed between and adjacent to the metal via and said another metal via,
wherein the air gap has a width that gradually reduces from top to bottom.