Method for forming a low-k dielectric structure on a substrate
View Patent ↗The present invention provides a method for forming a low-k dielectric structure on a substrate 10 that includes depositing, upon the substrate, a dielectric layer 12. A multi-film cap layer 18 is deposited upon the dielectric layer. The multi-film cap layer includes first 181 and second 182 films, with the second film being disposed between the dielectric layer and the first film. The first film typically has a removal rate associated therewith that is less than the removal rate associated with the second film. A deposition layer 20 is deposited upon the multi-film cap layer and subsequently removed. The properties of the multi-film cap layer are selected so as to prevent the dielectric layer from being exposed/removed during removal of the deposition film. In this manner, a deposition layer, having variable rates of removal, such as copper, may be planarized without damaging the underlying dielectric layer.
1. A method of forming a low-k dielectric structure on a substrate, said method comprising:
depositing, upon said substrate, a dielectric layer;
forming on said dielectric layer, a multi-film cap layer, said multi-film cap layer comprising first and second films, with said second film being disposed between said dielectric layer and said first film;
forming a deposition layer upon said multi-film cap layer, wherein said multi-film cap layer and said dielectric layer define a film stack; and
removing portions of said film stack, said portions comprising said deposition layer wherein said multi-film cap layer has properties to prevent said dielectric layer from being removed upon removal of said deposition film;
wherein removing further comprises removing substantially all of said first film.
2. The method as recited in claim 1 wherein removing portions further comprises providing said first film with properties to prevent said second film from being removed during removal of said deposition layer.
3. The method as recited in claim 1 wherein forming on said dielectric layer further comprises providing said first film with a dielectric constant greater than a dielectric constant associated with said second film.
4. The method as recited in claim 1 wherein said properties comprise removal rate and film thickness.
5. The method as recited in claim 1 wherein forming on said dielectric layer further comprises forming said first film from materials selected from a set consisting essentially of TEOS, SiON and SiN and forming said deposition layer further comprises forming said deposition layer from a conductive material.
6. The method as recited in claim 1 wherein depositing further comprises depositing an OSG layer having a first porosity associated therewith and forming on said dielectric layer further comprises forming said second film from an additional OSG layer having a second porosity associated therewith, with said second porosity being less than said first porosity.
7. The method as recited in claim 1 wherein removing said portions comprises planarizing said film stack employing a chemical mechanical polishing technique and providing said first film and said second film with a removal rate, with the removal rate of said first film being substantially less than a removal rate of said deposition layer.
8. The method as recited in claim 1 further comprising forming a trench into said dielectric layer extending therethrough, wherein forming said deposition layer further comprises depositing a conductive material onto said substrate, a first sub-portion of said conductive material filling said trench to form a conductive contact.
9. A method of forming a low-k dielectric structure upon a substrate, said method comprising:
depositing, upon said substrate, a dielectric layer having a first porosity associated therewith;
forming on said dielectric layer, a multi-film cap layer, said multi-film cap layer comprising a sacrificial film having a second porosity associated therewith and a second film having a third porosity associated therewith, with said first porosity being greater than said second and third porosities and said third porosity being greater than said second porosity, said second film being disposed between said dielectric layer and said sacrificial film;
forming a deposition layer upon said multi-film cap layer, with said deposition layer, said multi-film cap layer and said dielectric layer defining a film stack; and
removing portions of said film stack including substantially all of said sacrificial film, with said second and third porosities and a thickness of said first and second films being established to allow removal of said deposition layer from said film stack without removing said dielectric layer.
10. The method as recited in claim 9 wherein forming on said dielectric layer comprises providing said sacrificial film with a dielectric constant greater than a dielectric constant associated with said second film.
11. The method as recited in claim 9 wherein said properties comprise removal rate and film thickness.
12. The method as recited in claim 11 wherein depositing comprises depositing an OSG layer; forming on said dielectric layer further comprises forming said sacrificial film from materials from a set consisting essentially of TEOS, SiON and SiN and forming said second film from an additional OSG layer; and forming said deposition layer comprises forming said deposition layer of copper.
13. The method as recited in claim 9 wherein removing said portions further comprises planarizing said film stack employing a chemical mechanical polishing technique providing said sacrificial film and said second film with a removal rate, with the removal rate of said sacrificial film being substantially less than a removal rate of said deposition layer.
14. The method as recited in claim 9 further comprising forming a trench into said dielectric layer, wherein forming said deposition layer further comprises depositing copper material onto said substrate, with a first sub-portion of said copper material filling said trench to form a contact.
15. A semiconductor fabrication method for forming a dielectric film stack, comprising:
depositing a low k dielectric layer;
forming a capping layer on the low k layer;
depositing a sacrificial layer on the capping layer;
forming a trench through the sacrificial layer, the capping layer, and the low k dielectric layer;
depositing a conductive layer on the sacrificial layer and in the trench; and
removing portions of the conductive layer exterior to the trench, wherein said removing includes removing the sacrificial layer wherein a dielectric constant of the film stack is independent of a dielectric constant of the sacrificial layer.
16. The method of claim 15 , further comprising prior to depositing the low k dielectric, depositing a silicon nitride passivation layer and further wherein depositing the low k dielectric comprises depositing the low k dielectric on the passivation layer.
17. The method of claim 16 , wherein the sacrificial layer is a TEOS layer.
18. The method of claim 17 , wherein depositing the low k dielectric comprises depositing an organosilicate glass (OSG) and further wherein depositing the capping layer comprises depositing a second OSG layer and subsequently densifying the second OSG layer.
19. The method of claim 18 , wherein depositing the conductive layer comprises depositing copper and wherein removing portions of the conductive layer comprises chemical mechanical polishing the conductive layer.