Depositing a tantalum film
View Patent ↗This invention relates to a method of depositing a tantalum film in which α-Ta dominates and to methods of electroplating copper using such films. The films have a thickness of less than 300 nm and are formed by depositing a seed layer of an organic containing low dielectric constant insulating layer and sputtering tantalum onto the seed layer at a temperature below 250° C.
1. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C., wherein the seed layer is a methyl-doped silicon oxide.
2. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C. wherein the seed layer is formed by reacting a silicon containing organic compound and an oxidising agent in the presence of a plasma and setting the resultant film such that the carbon containing groups are contained therein.
3. A method as claimed in claim 2 wherein the seed layer is set by exposing it to an hydrogen containing plasma.
4. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C. wherein the surface of the seed layer has been etched away prior to tantalum deposition.
5. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C. wherein the seed layer is heated prior to tantalum deposition.
6. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C. wherein the tantalum source to substrate separation is at least 200 mm.
7. A method as claimed in claim 6 wherein the tantalum source to substrate distance is between 200 mm and 250 mm.
8. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C. wherein the tantalum deposition is by unbalanced magnetron sputtering.
9. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C. wherein the substrate is biased.
10. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C. wherein copper is deposited on the Ta film.
11. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C. wherein the seed layer is an inter metal dielectric layer.
12. A method of depositing Ta film in which α-Ta dominates having a thickness <300 nm comprising depositing a seed layer of an organic-containing low dielectric constant insulating layer and sputtering Tantalum to deposit a-Ta onto the seed layer at a temperature below 250° C. wherein a significant proportion of the tantalum material arrives at the seed layer in an ionised state.