Method of manufacturing a semiconductor device
View Patent ↗Exuding of a interconnecting material to a substrate, which occurs because of a thinned state of and a beak in a barrier metal layer is prevented, irrespective of a laminated state of the barrier metal layer. In the present invention, a protective layer is formed on a side wall by using an insulating film or the like after the deposition of the barrier metal layer, whereby the interconnecting material can be prevented from exuding to the substrate due to influence of heat treatment such as alloying, irrespective of the laminated state of the side wall of the contact hole and the barrier metal layer. Further, the formation of the protective layer allows the side wall to be smoother to thereby improve coverage of the interconnecting material at the same time.
1. A method of manufacturing a semiconductor device, comprising:
forming a first interlayer insulating film on a surface of a semiconductor substrate;
forming a second interlayer insulating film on a surface of the first interlayer insulating film;
performing patterning on a resist film applied on a surface of the second interlayer insulating film;
using the resist film as a mask, isotropically etching the first interlayer insulating film and the second interlayer insulating film to a preselected depth to form an opening for a contact hole followed by anisotropically etching the first interlayer insulating film and the second interlayer insulating film to form the contact hole having an upper part with a sloped surface and a lower part extending from the upper part and up to the surface of the semiconductor substrate;
forming a barrier metal layer on an inner wall of the contact hole and on the surface of the second interlayer insulating film;
depositing a protective film made of an insulating film on a surface of the barrier metal layer;
performing anisotropic etching to the protective film to leave the insulating film having a side wall shape so as to cover the surface of the barrier metal layer formed on a side wall of the contact hole, and the surface of the barrier metal layer formed on a side bottom surface of a contact hole, which corresponds to a junction between a side wall of the contact hole and a bottom surface of the contact hole;
depositing an interconnecting material on the insulating film of the side wall shape, the barrier metal layer, and the surface of the second interlayer insulating film; and
etching the barrier metal layer and the interconnecting material into a desired shape.
2. A method of manufacturing a semiconductor device according to claim 1 ; wherein:
the protective film comprises one of a BPSG film and an NSG film; and
the barrier metal layer comprises one of a TiN and a two-layered film including Ti and TiN.
3. A method of manufacturing a semiconductor device according to claim 1 ; wherein the anisotropic etching is
performed to the protective film so that the insulating film does not cover the sloped surface of the upper part of the contact hole.
4. A method of manufacturing a semiconductor device according to claim 1 ; wherein the sloped surface of the upper part of the contact hole is formed during isotropic etching of the first interlayer insulating film and the second interlayer insulating film.
5. A method of manufacturing a semiconductor device according to claim 1 ; wherein the sloped surface of the upper part of the contact hole is formed with a concave-shape.
6. A method of manufacturing a semiconductor device, comprising:
forming a first interlayer insulating film on a surface of a semiconductor substrate;
forming between the semiconductor substrate and the first interlayer insulating film a thin film having a composition that is easier to etch than the first interlayer insulating film;
forming a second interlayer insulating film on a surface of the first interlayer insulating film;
performing patterning on a resist film applied on a surface of the second interlayer insulating film;
using the resist film as a mask, isotropically etching the first interlayer insulating film and the second interlayer insulating film to a preselected depth to form an opening for a contact hole followed by anisotropically etching the first interlayer insulating film and the second interlayer insulating film to form the contact hole having an upper part with a sloped surface and a lower part extending from the upper part and up to the surface of the semiconductor substrate;
forming a barrier metal layer on an inner wall of the contact hole and on the surface of the second interlayer insulating film;
depositing a protective film made of an insulating film on a surface of the barrier metal layer;
performing anisotropic etching on the protective film to leave the insulating film in a side wall shape so as to cover the surface of the barrier metal layer formed on a side wall of the contact hole, and the surface of the barrier metal layer formed on a side bottom surface of a contact hole, which corresponds to a junction between a side wall of the contact hole and a bottom surface of the contact hole;
depositing a interconnecting material on the insulating film in the side wall shape, the barrier metal layer, and the surface of the second interlayer insulating film; and
etching the barrier metal layer and the interconnecting material into a desired shape.
7. A method of manufacturing a semiconductor device according to claim 6 ; wherein:
the protective film comprises one of a BPSG film and an NSG film; and
the barrier metal layer comprises one of a TiN and a two-layered film including Ti and TiN.
8. A method of manufacturing a semiconductor device according to claim 6 ; wherein the anisotropic etching is performed to the protective film so that the insulating film does not cover the sloped surface of the upper part of the contact hole.
9. A method of manufacturing a semiconductor device according to claim 6 ; wherein the sloped surface of the upper part of the contact hole is formed during isotropic etching of the first interlayer insulating film and the second interlayer insulating film.
10. A method of manufacturing a semiconductor device according to claim 6 ; wherein the sloped surface of the
upper part of the contact hole is formed with a concave-shape.
11. A method of manufacturing a semiconductor device, comprising the steps of:
forming a first interlayer insulating film on a surface of a semiconductor substrate;
forming a second interlayer insulating film on a surface of the first interlayer insulating film;
forming a resist film on a surface of the second interlayer insulating film;
patterning the resist film;
etching the first interlayer insulating film and the second interlayer insulating film using the patterned resist film as a mask to form a contact hole having an upper part with a sloped surface and a lower part extending from the upper part and up to the surface of the semiconductor substrate;
forming a barrier metal layer on an inner wall of each of the upper part and the lower part of the contact hole;
depositing an insulating film on a surface of the barrier metal layer formed on the inner wall of each of the upper part and the lower part of the contact hole;
anisotropically etching the insulating film so that the insulating film covers the inner wall of the lower part of the contact hole but not the inner wall of the upper part of the contact hole;
depositing an interconnecting material on the etched insulating film, the barrier metal layer, and the surface of the second interlayer insulating film; and
etching the barrier metal layer and the interconnecting material into a desired shape.
12. A method according to claim 11 ; further comprising the step of, before the step of forming the second interlayer insulating film, forming between the semiconductor substrate and the first interlayer insulating film a thin film having a composition that is easier to etch than the first interlayer insulating film.
13. A method according to claim 12 ; wherein the insulating film comprises one of a BPSG film and an NSG film; and wherein the barrier metal layer comprises one of a TiN and a two-layered film including Ti and TIN.
14. A method according to claim 11 ; wherein the insulating film comprises one of a BPSG film and an NSG film; and wherein the barrier metal layer comprises one of a TiN and a two-layered film including Ti and TIN.
15. A method according to claim 11 ; wherein the step of etching the first interlayer insulating film and the second interlayer insulating film comprises the steps of isotropically etching the first interlayer insulating film and the second interlayer insulating film followed by anisotropically etching the first interlayer insulating film and the second interlayer insulating film to form the upper and lower parts of the contact hole.
16. A method according to claim 15 ; wherein the upper part of the contact hole is formed with a sloped surface.
17. A method according to claim 16 ; wherein the sloped surface of the upper part of the contact hole is formed during isotropic etching of the first interlayer insulating film and the second interlayer insulating film.
18. A method according to claim 17 ; further comprising the step of, before the step of forming the second interlayer insulating film, forming between the semiconductor substrate and the first interlayer insulating film a thin film having a composition that is easier to etch than the first interlayer insulating film.
19. A method of manufacturing a semiconductor device according to claim 16 ; wherein the sloped surface of the upper part of the contact hole is formed with a concave-shape.
20. A method according to claim 19 ; further comprising the step of, before the step of forming the second interlayer insulating film, forming between the semiconductor substrate and the first interlayer insulating film a thin film having a composition that is easier to etch than the first interlayer insulating film.