Premetal dielectric integration process

• US 8,685,867 B1
• Filed: 12/08/2011
• Issued: 04/01/2014
• Est. Priority Date: 12/09/2010
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (LAM Research Corporation)
• Original Assignee: Novellus Systems Incorporated (LAM Research Corporation)
• Inventors: Danek, Michal, van Schravendijk, Bart, Draeger, Nerissa, Nittala, Lakshminarayana
• Primary Examiner(s): Geyer, Scott B
• Assistant Examiner(s): Seven, Evren
• Application Number:
  US13/315,123
• Time in Patent Office: 845 Days
• Field of Search: None
• US Class Current: 438/787
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/76801 characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: H01L 21/76825 by exposing the layer to particle radiation, e.g. ion implantation, irradiation with UV light or electrons etc. plasma treatment H01L21/76826
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76828 thermal treatment
• CPC Class Codes: H01L 21/76837 Filling up the space between adjacent conductive structures; Gap-filling properties of dielectrics

Abstract

Provided herein are novel pre-metal dielectric (PMD) integration schemes. According to various embodiments, the methods involve depositing flowable dielectric material to fill trenches or other gaps between gate structures in a front end of line (FEOL) fabrication process. The flowable dielectric material may be partially densified to form dual density filled gaps having a low density region capped by a high density region. In certain embodiments, the methods include further treating at least a portion of the gap fill material after subsequent process operations such as chemical mechanical planarization (CMP) or contact etching.

Claims

1. A method for filling a recessed feature with dielectric material, comprising:

providing a workpiece including gate structures disposed on a substrate, with a gap between the gate structures;

filling the gap with a flowable dielectric material, filling the gap comprising flowing process gasses into a deposition chamber housing the substrate under the conditions such that a flowable film forms and fills the gap; and

partially densifying the flowable dielectric material to form a dual density filled gap comprising a lower density dielectric fill region capped by a higher density dielectric fill region.

2. The method of claim 1 further comprising performing subsequent processing operations comprising at least one of chemical mechanical planarization and contact etch on the substrate.

3. The method of claim 1 further comprising etching a hole within the filled gap to expose an underlying contact, such that sidewalls of the hole include exposed dielectric fill material.

4. The method of claim 3 further comprising densifying at least a portion of the exposed dielectric fill material.

5. The method of claim 3 further comprising depositing a liner on at least a portion of the exposed dielectric fill material.

6. The method of claim 1 wherein the flowable dielectric material is a silicon nitride material.

7. The method of claim 1 wherein the gap is filled using a single cycle deposition.

8. The method of claim 1 wherein partially densifying the flowable dielectric material comprises exposing it to an oxidizing radicals from a downstream or direct plasma.

9. The method of claim 1 wherein partially densifying the flowable dielectric material comprises exposing it to ultraviolet radiation in a non-oxidizing environment.

10. The method of claim 1 wherein partially densifying the flowable dielectric material comprises exposing it to an oxidant in the presence of ultraviolet radiation.

11. The method of claim 1 wherein partially densifying the flowable dielectric material comprises exposing to a nitridizing radicals from a downstream or direct plasma.

12. The method of claim 1 wherein partially densifying the flowable dielectric material comprises removing at least one of hydrogen (—

H), hydroxyl (—

OH), alkyl (—

CH) or amine (—

NH) groups from the flowable dielectric material.

13. The method of claim 1 wherein partially densifying the flowable dielectric material comprises removing amine groups from the flowable dielectric material.

14. The method of claim 1 wherein partially densifying the flowable dielectric material comprises forming Si—

O—

Si linkages.

24. The method of claim 1, wherein filling the gap with a flowable dielectric material comprises exposing the substrate to process gases under conditions such that a flowable film forms and fills the gap.

25. The method of claim 1, wherein the gate structures comprise transistor gates at the device level of a partially fabricated integrated circuit.

26. The method of claim 1, wherein the gate structures comprise dummy gate structures at the device level of a partially fabricated integrated circuit.

15. A method for filling a gap, comprising:

providing a workpiece including a gap;

filling the gap with a flowable dielectric material;

performing a first treatment on the dielectric material in the gap;

after exposing the dielectric material to the first treatment, removing a portion of the dielectric material in the gap to create a hole including one or more sidewalls; and

after removing the portion of the dielectric material, performing a second treatment on the dielectric material in the gap.

16. The method of claim 15 wherein performing the first treatment comprises partially densifying the flowable dielectric material to form a dual density filled gap comprising a lower density dielectric fill region capped by a higher density dielectric fill region.

17. The method of claim 16 wherein removing a portion of the dielectric material comprises etching the dual density filled gap to expose a portion of the lower density dielectric fill region.

18. The method of claim 17 wherein performing the second treatment comprises treating the exposed portion of the lower density dielectric fill region.

19. The method of claim 17 wherein treating the exposed portion comprises densifying the exposed dielectric fill material.

20. The method of claim 17 wherein treating the exposed portion comprises depositing a liner thereon.

21. The method of claim 16 further comprising, after performing the second treatment, exposing the treated dielectric material to a wet etchant.

22. The method of claim 15 wherein at least one of the first and second treatments comprises exposing the dielectric material to a reactive oxidant in the presence of RF energy or ultraviolet radiation.

23. The method of claim 15 wherein at least one of the first and second treatments comprises exposing the dielectric material to ultraviolet radiation in an non-oxidizing environment.