Claims
- 1. A method of forming a shallow trench isolation structure, said method comprising:
providing a substrate having a shallow trench formed therein; depositing a conformal barrier layer within said shallow trench; filling said shallow trench with a low k dielectric layer; planarizing said low k dielectric layer to a level that is approximately coplanar with said substrate; etching back the planarized low k dielectric layer to a lower level in said shallow trench; depositing a barrier cap layer; and planarizing said barrier cap layer to a level above said substrate.
- 2. The method of claim 1 wherein said shallow trench has sloped sidewalls and is wider at the top than at the bottom.
- 3. The method of claim 1 wherein said conformal barrier layer is comprised of silicon oxide, silicon nitride, or silicon oxynitride.
- 4. The method of claim 1 wherein said conformal barrier layer is composite of two layers.
- 5. The method of claim 1 wherein said low k dielectric material has a dielectric constant of 2.9 or less.
- 6. The method of claim 1 wherein said low k dielectric material is deposited by a chemical vapor deposition (CVD), plasma enhanced CVD (PECVD) or by a spin-on process.
- 7. The method of claim 1 said low k dielectric layer is planarized by a chemical mechanical polish (CMP) step.
- 8. The method of claim 1 wherein said etching back step is performed with a plasma etch or with a buffered HF dip.
- 9. The method of claim 1 wherein said barrier cap material is comprised of silicon nitride, silicon oxynitride or silicon carbide.
- 10. The method of claim 1 wherein said barrier cap material is comprised of a low k dielectric material.
- 11. The method of claim 10 wherein said low k dielectric material is comprised of a carbon doped oxide referred to as SiCOH.
- 12. The method of claim 111 wherein said SiCOH material in said barrier cap layer is modified with a plasma treatment to provide a dielectric constant below 2.9.
- 13. The method of claim 11 wherein said SiCOH material in said barrier cap layer is modified with a plasma treatment to reduce its polish rate in a CMP process.
- 14. The method of claim 11 further comprised of performing a second plasma treatment on said SiCOH layer after said barrier cap layer planarization in order to densify and stabilize said SiCOH layer.
- 15. A method of forming a shallow trench isolation structure, said method comprising:
providing a substrate having a stack comprised of an upper silicon nitride layer and a lower pad oxide layer formed thereon; forming a shallow trench that extends through said stack and into said substrate; depositing a conformal barrier layer on said substrate and within said shallow trench; filling said shallow trench with a low k dielectric layer; planarizing said low k dielectric layer to a level that is approximately coplanar with said silicon nitride layer; etching back the planarized low k dielectric layer to a lower level in said shallow trench; depositing a barrier cap layer; planarizing said barrier cap layer to a level that is approximately coplanar with said silicon nitride layer; and removing said silicon nitride and pad oxide layers.
- 16. The method of claim 15 wherein said shallow trench has sloped sidewalls and is wider at the top than at the bottom.
- 17. The method of claim 15 wherein said conformal barrier layer is comprised of silicon oxide, silicon nitride, or silicon oxynitride.
- 18. The method of claim 15 wherein said conformal barrier layer is composite of two dielectric materials selected from the group of silicon oxide, silicon nitride or silicon oxynitride.
- 19. The method of claim 15 wherein said low k dielectric material has a dielectric constant of 2.9 or less.
- 20. The method of claim 15 said low k dielectric layer is planarized by a chemical mechanical polish (CMP) step.
- 21. The method of claim 15 wherein said etching back step is performed with a plasma etch or with a buffered HF dip.
- 22. The method of claim 15 wherein said barrier cap material is comprised of silicon nitride, silicon oxynitride or silicon carbide.
- 23. The method of claim 15 wherein said barrier cap material is comprised of a low k dielectric material.
- 24. The method of claim 23 wherein said low k dielectric material is comprised of a carbon doped oxide referred to as SiCOH.
- 25. The method of claim 24 wherein said SiCOH material in said barrier cap layer is modified with a plasma treatment to provide a dielectric constant below 2.9.
- 26. The method of claim 24 wherein said SiCOH material in said barrier cap layer is modified with a plasma treatment to reduce its polish rate in a CMP process.
- 27. The method of claim 23 further comprised of performing a second plasma treatment on said SiCOH layer after said barrier cap layer planarization in order to densify and stabilize said SiCOH layer.
- 28. A method of forming a shallow trench isolation structure, said method comprising:
providing a substrate having a stack comprised of an upper silicon nitride layer and a lower pad oxide layer formed thereon; forming a shallow trench that extends through said stack and into said substrate; depositing a conformal barrier layer within said shallow trench; filling said shallow trench with a low k dielectric layer; planarizing said low k dielectric layer to a level that is approximately coplanar with said silicon nitride layer; and removing said silicon nitride and pad oxide layers.
- 29. The method of claim 28 wherein said shallow trench has sloped sidewalls and is wider at the top than at the bottom.
- 30. The method of claim 28 wherein said conformal barrier layer is comprised of silicon oxide, silicon nitride, or silicon oxynitride.
- 31. The method of claim 28 wherein said conformal barrier layer is composite comprised two dielectric materials selected from the group of silicon oxide, silicon nitride or silicon oxynitride.
- 32. The method of claim 28 wherein said low k dielectric material has a dielectric constant of 2.9 or less.
- 33. The method of claim 28 said low k dielectric layer is planarized by a chemical mechanical polish (CMP) step.
- 34. The method of claim 28 wherein said low k dielectric material is comprised of a carbon doped oxide referred to as SiCOH.
- 35. The method of claim 34 wherein said SiCOH material is modified with a plasma treatment to provide a dielectric constant below 2.9.
- 36. The method of claim 34 wherein said SiCOH material is modified with a plasma treatment to reduce its polish rate in a CMP process.
- 37. The method of claim 34 further comprised of performing a second plasma treatment on said SiCOH layer after said barrier cap layer planarization in order to densify and stabilize said SiCOH layer.
- 38. The method of claim 28 further comprised of completing a transistor in an active area adjacent to said trench structure by fabricating a gate electrode on a gate dielectric layer, forming spacer sidewalls on the gate electrode, and forming lightly doped source/drain (S/D) regions and heavily doped S/D regions in said substrate.
- 39-57. (Canceled).
RELATED PATENT APPLICATION
[0001] This application is related to the following: Docket # TSMC01-1654, Ser. No. 10/270,974, filing date Oct. 15, 2002.