Method for forming metal wires in semiconductor device
View Patent ↗The present invention provides a method that can prevent an anti-diffusion film from being formed defectively on a porous dielectric film due to pores in method for forming metal wires in a semiconductor device in which the porous dielectric film is used as an insulating film between metal wires. The method includes forming a porous dielectric film on a semiconductor substrate as an insulating film between metal wires, selectively etching the porous dielectric film to form an aperture defining a metal wire region, infiltrating sealing particles into pores of the porous dielectric film exposed on the sidewall of the aperture, implementing an annealing process for agglomerating the sealing particles to seal the entrances of the pores of the porous dielectric film exposed on the sidewall of the aperture, forming an anti-diffusion film at the bottom and on the sidewall of the aperture, forming a metal film on the anti-diffusion film, and polishing the metal film and the anti-diffusion film until the top of the porous dielectric film is formed to metal wires within the aperture.
1. A method for forming metal wires in a semiconductor device, comprising the steps of:
forming a porous dielectric film on a semiconductor substrate as an insulating film between metal wires;
selectively etching the porous dielectric film to form an aperture defining a metal wire region;
infiltrating sealing particles into pores of the porous dielectric film exposed on the sidewall of the aperture;
implementing an annealing process for agglomerating the sealing particles to seal the entrances of the pores of the porous dielectric film exposed on the sidewall of the aperture;
forming an anti-diffusion film at the bottom and on the sidewall of the aperture;
forming a metal film on the anti-diffusion film; and
polishing the metal film and the anti-diffusion film until the top of the porous dielectric film is formed to metal wires within the aperture.
2. The method as claimed in claim 1 , wherein the step of infiltrating the sealing particles into the pores of the porous dielectric film exposed on the sidewall of the aperture comprises the steps of:
impregnating a solution containing the sealing particles into the porous dielectric film; and
annealing the porous dielectric film into which the solution is impregnated.
3. The method as claimed in claim 2 , wherein the dielectric constant of the porous dielectric film is no more than 2.5.
4. The method as claimed in claim 3 , wherein the porous dielectric film into which the solution is impregnated is annealed at a temperature of 100° C. to 300° C.
5. The method as claimed in claim 1 , wherein the sealing particles are metallic particles of at least one kind.
6. The method as claimed in claim 5 , wherein the sealing particles are metallic particles of at least one kind selected from Pt, Ru and Pd.
7. The method as claimed in claim 5 , wherein at least one of H 2 PtCl 6 , RuCl 3 and PdCl 2 is dissolved into the solution containing the sealing particles.
8. The method as claimed in claim 5 , wherein the annealing process for agglomerating the sealing particles is performed at a temperature of 200° C. to 600° C.
9. The method as claimed in claim 8 , wherein the annealing process for agglomerating the sealing particles is performed under a N 2 , Ar, H 2 or He gas atmosphere.
10. The method as claimed in claim 5 , wherein the metal film is formed using a Cu film.
11. The method as claimed in claim 10 , wherein the anti-diffusion film is formed using Ta or TaN.
12. The method as claimed in claim 5 , wherein the aperture includes a trench and a via connected to the trench.