Integration of pore sealing liner into dual-damascene methods and devices
A device employs damascene layers with a pore sealing liner and includes a semiconductor body. A metal interconnect layer comprising a metal interconnect is formed over the semiconductor body. A dielectric layer is formed over the metal interconnect layer. A conductive trench feature and a conductive via feature are formed in the dielectric layer. A pore sealing liner is formed only along sidewall of the conductive via feature and along sidewalls and bottom surfaces of the conductive trench feature. The pore sealing liner is not substantially present along a bottom surface of the conductive via feature.
1. A method of fabricating a semiconductor device comprising:
forming a dielectric layer over a semiconductor body;
forming a via cavity within the dielectric layer;
forming a trench cavity within the dielectric layer;
forming a pore sealing liner on bottom and sidewall surfaces of the trench cavity and the via cavity; and
performing a selective etch-deposition process that forms a metal barrier layer on sidewall surfaces of the via cavity and on sidewall and bottom surfaces of the trench cavity and that removes the pore sealing liner from at least a portion of the bottom surface of the via cavity without substantially removing the pore sealing liner from the bottom surface of the trench cavity.
2. The method of claim 1 , wherein forming the dielectric layer comprises depositing a porous, low-k dielectric material over the semiconductor body.
3. The method of claim 1 , further comprising forming a second metal barrier layer on the pore sealing liner prior to performing the selective etch-deposition process.
4. The method of claim 3 , wherein forming the second metal barrier layer comprises depositing a conductive material by physical vapor deposition.
5. The method of claim 3 , wherein forming the second metal barrier layer comprises depositing a conductive material by atomic layer deposition.
6. The method of claim 1 , further comprising forming a final metal barrier layer after performing the selective etch-deposition process and filling the via cavity and the trench cavity with a conductive fill material and planarizing a surface of the device to remove excess fill material.
7. The method of claim 1 , wherein performing the selective etch-deposition process has an etch rate that exceeds a deposition rate at the bottom surface of the via cavity.
8. The method of claim 1 , wherein performing the selective etch-deposition process has an etch rate at the center of the via cavity bottom surface greater than a etch rate near the edge of the via cavity bottom surface.
9. The method of claim 8 , further comprising selecting the via-center etch rate and the via-edge etch rate according to allowable misalignment between the via and underlying metal structure.
10. A method of fabricating a semiconductor device comprising:
forming a metal interconnect layer having a metal interconnect over a semiconductor body;
forming a low-k dielectric layer on the metal interconnect layer;
forming a via cavity within the dielectric layer;
forming a trench cavity within the dielectric layer;
forming a pore sealing liner on bottom and sidewall surfaces of the trench cavity and the via cavity;
forming a first metal layer comprised of a metal material on the pore sealing liner, wherein the pore sealing liner mitigates migration of the metal material into the first and second dielectric layers;
performing a selective etch-deposition process that etches the pore sealing liner from the bottom surface of the via cavity and deposits a second metal barrier layer over sidewall surfaces of the via cavity and over sidewall and bottom surfaces of the trench cavity; and
forming a conductive via feature within the via cavity and on the metal interconnect and forming a conductive trench feature within the trench cavity.
11. The method of claim 10 , wherein forming the first dielectric layer comprises depositing an ultra-low k dielectric material.
12. The method of claim 10 , wherein the selective-etch deposition process has a higher etch rate than deposition rate at the bottom surface of the via cavity.
13. The method of claim 10 , wherein forming the first metal barrier layer comprises depositing the metal material by an atomic layer deposition or a chemical vapor deposition process.
14. The method of claim 10 , wherein forming the first metal barrier layer comprises depositing the metal material by a physical vapor deposition process.