Technique for forming a dielectric etch stop layer above a structure including closely spaced lines
When forming line structures of semiconductor devices in accordance with the 90 nm technology, sidewall spacers of the lines are reduced in size immediately prior to the deposition of an etch stop layer that is formed on the device layer. Due to the reduced spacer elements or due to a complete removal of the spacer elements, the subsequent deposition of the etch stop layer and of the interlayer dielectric is significantly enhanced with respect to void formation and defect rate.
1. A method, comprising:
forming a structure above a substrate with a first line with a first spacer element formed on a sidewall thereof and a second line with a second spacer element formed on a sidewall thereof, said first and second spacer elements facing each other and defining a spacing therebetween;
forming a metal-containing region of increased conductivity on each of said lines using said first and second spacer elements as a reaction mask to cover at least a portion of said substrate during the forming of said metal-containing region;
removing material from said first and second spacer elements to increase said spacing after forming said metal containing region; and
depositing an etch stop layer above said structure.
2. The method of claim 1 , wherein said spacing is less than approximately 100 nm.
3. The method of claim 1 , wherein said material of the first and second spacer elements is removed by an etch process having a reduced removal rate in said metal-containing region compared to said material of the first and second spacer elements.
4. The method of claim 3 , wherein said etch process comprises a plasma etch process.
5. The method of claim 4 , wherein said plasma etch process is performed with an etch chemistry on the basis of carbon monoxide (CO), a carbon/hydrogen/fluorine (CHF) compound and oxygen.
6. The method of claim 5 , wherein said carbon/hydrogen/fluorine (CHF) compound comprises CH 3 F.
7. The method of claim 1 , wherein said first and second spacer elements are substantially completely removed.
8. The method of claim 1 , further comprising depositing an interlayer dielectric on said etch stop layer.
9. The method of claim 8 , further comprising forming a contact opening in said interlayer dielectric.
10. The method of claim 1 , further comprising recessing said first and second spacer elements prior to forming said metal-containing region to expose a first portion of the sidewall of the first line and a second portion of the sidewall of the second line.
11. The method of claim 10 , wherein recessing said first and second spacer elements comprises establishing a relationship between a degree of recess and a size of said metal-containing region and etching said first and second spacer elements on the basis of said relationship.
12. The method of claim 10 , further comprising implanting a dopant species into said substrate while using said first and second lines and said first and second spacer elements as an implantation mask.
13. The method of claim 12 , wherein implanting said dopant species is performed prior to recessing said first and second spacer elements.
14. The method of claim 12 , wherein recessing said first and second spacer elements comprises establishing a relationship between a degree of recess and a size of said metal-containing region and a blocking effect required for said implantation of the dopant species, etching said first and second spacer elements on the basis of said relationship and implanting said dopant species while using said recessed first and second spacer elements as an implantation mask.
15. The method of claim 8 , wherein forming said interlayer dielectric comprises depositing above said etch stop layer a first silicon dioxide layer by one of a thermal chemical vapor deposition process based on TEOS and a high density plasma chemical vapor deposition process.
16. The method of claim 15 , wherein forming said interlayer dielectric further comprises depositing a second layer of silicon dioxide on said first layer by a plasma enhanced chemical vapor deposition process based on TEOS.
17. A method, comprising:
forming a structure above a substrate with a first line with a first spacer element formed on a sidewall thereof and a second line with a second spacer element formed on a sidewall thereof, said first and second spacer elements facing each other and defining a spacing therebetween;
forming a metal-containing region of increased conductivity on each of said lines using said first and second spacer elements as a reaction mask to cover at least a portion of said substrate during the forming of said metal-containing region;
removing material from said first and second spacer elements to increase said spacing by a selective etch process having a higher removal rate for said spacer material compared to said metal-containing region after forming said metal-containing region; and
depositing an etch stop layer above said structure.
18. The method of claim 17 , wherein said spacing is less than 100 nm.
19. The method of claim 18 , wherein said spacing is approximately 30 nm or less.
20. The method of claim 17 , wherein said etch process is a plasma etch process on the basis of carbon monoxide (CO), a carbon/hydrogen/fluorine (CHF) compound and oxygen.
21. The method of claim 15 , wherein said carbon/hydrogen/fluorine (CHF) compound comprises CH 3 F.
22. The method of claim 17 , wherein said first and second spacer elements are substantially completely removed.
23. The method of claim 17 , further comprising depositing an interlayer dielectric on said etch stop layer.
24. The method of claim 23 , further comprising forming a contact opening in said interlayer dielectric.
25. The method of claim 17 , further comprising recessing said first and second spacer elements prior to forming said metal-containing region to expose a first portion of the sidewall of the first line and a second portion of the sidewall of the second line.
26. The method of claim 25 , wherein recessing said first and second spacer elements comprises establishing a relationship between a degree of recess and a size of said metal-containing region and etching said first and second spacer elements by controlling at least one etch parameter on the basis of said relationship.
27. The method of claim 17 , further comprising implanting a dopant species into said substrate while using said first and second lines and said first and second spacer elements as an implantation mask.
28. The method of claim 27 , wherein implanting said dopant species is performed prior to recessing said first and second spacer elements.
29. The method of claim 27 , wherein recessing said first and second spacer elements comprises establishing a relationship between a degree of recess and a size of said metal-containing region and a blocking effect required for said implantation of the dopant species, etching said first and second spacer elements on the basis of said relationship and implanting said dopant species while using said recessed first and second spacer elements as an implantation mask.
30. The method of claim 23 , wherein forming said interlayer dielectric comprises depositing above said etch stop layer a first silicon dioxide layer by one of a thermal chemical vapor deposition process based on TEOS and a high density plasma chemical vapor deposition process.
31. The method of claim 30 , wherein forming said interlayer dielectric further comprises depositing a second layer of silicon dioxide on said first layer by a plasma enhanced chemical vapor deposition process based on TEOS.