Differential trench fill for ease of layout design

1. An integrated circuit structure, comprising:

a plurality of structures above a substrate, wherein spacing between the structures creates a range of different open density regions from a relatively low open density region to a high open density region;

a first fill material filling at least a portion of openings between the structures in at least the high open density region to provide a substantially uniform open density across the different open density regions, wherein the first fill material is patterned to include openings therein; and

a second fill material filling the openings between the structures in the low open density region, and filling the openings in the first fill material in the at least the high open density region,

wherein the structures filled with the second fill material in the low open density region and the structures filled with both the first fill material and the second fill material in the high open density region are substantially planar at a desired final height.

2. The integrated circuit structure of claim 1 , wherein the integrated circuit structure includes a first set of structures having a low open density region, a second set of structures having a medium open density region, and a third set of structures corresponding to the high open density region.

3. The integrated circuit structure of claim 2 , wherein the first fill material is deposited over any of the open density regions having an open density of at least 50%.

4. The integrated circuit structure of claim 3 , wherein the first fill material is patterned to fill at least a portion of openings between the structures in the medium open density region and the high open density region.

5. The integrated circuit structure of claim 3 , wherein the second fill material fills the openings in both the first fill material in the medium open density region and the high open density region.

6. The integrated circuit structure of claim 1 , wherein, the first fill material is patterned into parallel spaced strips formed across the openings formed by the structures.

7. The integrated circuit structure of claim 1 , wherein the first fill material and the second fill material are tuned to provide the same final height for the structures in the different open density regions.

8. The integrated circuit structure of claim 1 , wherein the first fill material and the second fill material are tuned to provide different final heights for the structures in the different open density regions.

9. The integrated circuit structure of claim 1 , wherein the structures comprise spacers that define gate regions, wherein the first fill material and the second fill material comprise a conductive fill material, and wherein the spacers, the first fill material and the second fill material are substantially planar and 50-300 nm in height.

10. The integrated circuit structure of claim 1 , wherein the first fill material and the second fill material comprise a non-conductive material.

11. The integrated circuit structure of claim 1 , wherein the first fill material and the second fill material comprise a same material.

12. The integrated circuit structure of claim 1 , wherein the first fill material and the second fill material comprise a different material.

13. An integrated circuit structure, comprising:

a plurality of spacers above a substrate, wherein spacing between the spacers creates a range of different open density regions including a low open density region, a medium open density region and a high open density region;

a first conductive fill material filling at least a portion of trenches formed between the spacers in the medium open density region and the high open density region to provide a substantially uniform open density across the different open density regions; and

a second conductive fill material filling trenches between the spacers in the low open density region, the second conductive fill material further filling the trenches in the first conductive fill material in both the medium open density region and in the high open density region;

wherein the spacers and the second conductive fill material in the low open density region, and the spacers and the first conductive fill material and the second conductive fill material in both the medium open density region and the high open density region are substantially planar at a desired final height.

14. The integrated circuit structure of claim 13 , wherein the first conductive fill material is deposited over any of the open density regions having an open density of at least 50%.

15. The integrated circuit structure of claim 13 , wherein, the first conductive fill material is patterned into parallel spaced strips across the trenches between the spacers.

16. The integrated circuit structure of claim 13 , wherein the first conductive fill material and the second conductive fill material are tuned to provide the same final height for the spacers in the different open density regions.

17. The integrated circuit structure of claim 13 , wherein the first conductive fill material and the second conductive fill material are tuned to provide different final heights for the spacers in the different open density regions.

18. The integrated circuit structure of claim 13 , wherein the spacers define gate regions.

19. The integrated circuit structure of claim 13 , wherein the spacers, the first conductive fill material and the second conductive fill material are substantially planar and 50-300 nm in height.

20. The integrated circuit structure of claim 13 , wherein the first conductive fill material and the second conductive fill material comprise a non-conductive material.

21. The integrated circuit structure of claim 13 , wherein the first conductive fill material and the second conductive fill material comprise a same material.

22. The integrated circuit structure of claim 13 , wherein the first conductive fill material and the second conductive fill material comprise a different material.

23. A method of fabricating an integrated circuit (IC) device, the method comprising:

forming a plurality of structures above a substrate, wherein spacing between the structures creates a range of different open density regions from a relatively low open density region to a high open density region;

forming a first fill material that fills at least a portion of openings between the structures in at least the high open density region to provide a substantially uniform open density across the different open density regions, wherein the first fill material is patterned to include openings therein; and

forming a second fill material that fills the openings between the structures in the low open density region, and forming the second fill material in the openings in the first fill material in the at least the high open density region,

wherein the structures filled with the second fill material in the low open density region and the structures filled with both the first fill material and the second fill material in the high open density region are substantially planar at a desired final height.

24. The method of claim 23 , wherein forming a first fill material further comprises: using a single patterning process to deposit and etch the first fill material differently in the different open density regions to form different patterns.

25. The method of claim 23 , wherein forming a first fill material further comprises: etching the first fill material such that an increasingly larger amount of the first fill material is patterned over increasingly higher open density regions.