Conductive interconnect having a semi-liner and no top surface recess
According to embodiments of the present invention, a semiconductor wafer includes a substrate and an interlayer dielectric located on the substrate. The interlayer dielectric includes an interconnect. A barrier layer is located in between the interconnect and the interlayer dielectric. A semi-liner layer is located in between the interconnect and the barrier layer. The interlayer dielectric, the interconnect, and barrier layer form a substantially planar surface opposite the substrate. The interconnect has an interconnect height from a base to the substantially planar surface and a semi-liner height of the semi-liner layer is less than the interconnect height such that liner layer does not extend to the planar surface.
1. A method of forming a semiconductor wafer, the method comprising:
depositing a barrier layer on an interlayer dielectric comprising a trench;
depositing a liner layer on the barrier layer;
depositing a first conductive material on the liner layer to fill the trench;
selectively etching the first conductive material to a depth, d, to form a conductive material recessed area;
selectively etching the liner layer to a depth, d 1 , to reduce a wall height of the liner layer to form a semi-liner layer having a semi-liner height and to form a liner recessed area, wherein the depth, dl, is within 30% of the depth, d;
depositing a second conductive material to fill the liner recessed area to form an interconnect; and
planarizing the second conductive material to form a planar surface, wherein the interlayer dielectric, the interconnect, and barrier layer form the planar surface and wherein the semi-liner height of the semi-liner layer is less than the interconnect height such that liner layer does not extend to the planar surface.
2. The method of claim 1 , wherein the depth, d 1 , is within 30% of the depth, d.
3. The method of claim 1 , wherein the semi-liner height is 10 to 90% of the interconnect height.
4. The method of claim 1 , wherein the semi-liner height is 20 to 80% of the interconnect height.
5. The method of claim 1 , wherein the planar surface is substantially free of both recesses and crevices.
6. The method of claim 1 , further comprising forming the trench in the interlayer dielectric prior to depositing the barrier layer.
7. The method of claim 6 , further comprising depositing the interlayer dielectric on a substrate prior to forming the trench.
8. A method of forming a semiconductor wafer, the method comprising:
depositing a barrier layer on an interlayer dielectric comprising a trench; depositing a liner layer on the barrier layer;
depositing a first conductive material on the liner layer to fill the trench, wherein depositing the first conductive material comprises first depositing a first copper seed layer and then electroplating a first copper fill layer on the first copper seed layer;
selectively etching the first conductive material to a depth, d, to form a conductive material recessed area:
selectively etching the liner layer to a depth, di, to reduce a wall height of the liner layer to form a semi-liner layer having a semi-liner height and to form a liner recessed area;
depositing a second conductive material to fill the liner recessed area to form an interconnect, wherein depositing the second conductive material comprises first depositing a second copper seed layer and then electroplating a second copper fill layer on the second copper seed layer;
planarizing the second conductive material to form a planar surface, wherein the interlayer dielectric, the interconnect, and barrier layer form the planar surface and wherein the semi-liner height of the semi-liner layer is less than the interconnect height such that liner layer does not extend to the planar surface.
9. The method of claim 8 , wherein the semi-liner height is 10 to 90% of the interconnect height.
10. The method of claim 8 , wherein the semi-liner height is 20 to 80% of the interconnect height.
11. The method of claim 8 , wherein the planar surface is substantially free of both recesses and crevices.
12. The method of claim 8 , further comprising forming the trench in the interlayer dielectric prior to depositing the barrier layer.
13. The method of claim 12 , further comprising depositing the interlayer dielectric on a substrate prior to forming the trench.