Stretch dummy cell insertion in FinFET process

1. A method comprising:

identifying an empty region in an integrated circuit (IC) layout, wherein the empty region is a region not including any active fins and outside a minimum spacing boundary;

applying a grid map over the empty region, wherein the grid map comprises a plurality of grids inside the empty region;

filling the empty region with a plurality of dummy fin cells by placing a dummy fin cell in each of the plurality of grids, wherein applying the grid map and filling the empty region is performed using a computer; and

implementing the plurality of dummy fin cells in an IC.

2. The method of claim 1 , wherein each of the plurality of grids is of an equal size and aligned with a point in the empty region.

3. The method of claim 2 , wherein the size of each of the plurality of grids is configured in accordance with a size of the dummy fin cell and a desired pitch.

4. The method of claim 1 , wherein placing a dummy fin cell in each of the plurality of grids further comprises placing a dummy fin cell in a same relative position in each of the plurality of grids.

5. The method of claim 1 , further comprising, after filling the empty region:

identifying a gap in the empty region, wherein the grid map overlays the gap; and

replacing the dummy fin cell in a grid adjacent to the gap with an expanded dummy fin cell, wherein the expanded dummy fin cell is outside the minimum spacing boundary, and wherein the expanded dummy fin cell comprises a first portion in the grid adjacent the gap and a second portion filling the gap.

6. The method of claim 5 , wherein the dummy fin cell comprises two edge portions and a standard center portion, and wherein the expanded dummy fin cell comprises the two edge portions and an expanded center portion, the expanded center portion being a multiple of the standard center portion.

7. A method for designing and forming an integrated circuit (IC) comprising:

designing an IC layout, wherein designing the IC comprises:

identifying, by a processor, an empty region in the IC layout, wherein the IC layout comprises an active fin region, and wherein the empty region is separated from the active fin region by a minimum spacing constraint region;

selecting a starting point in the empty region;

laying, by the processor, a grid map over the empty region and the minimum spacing constraint region, wherein the grid map comprises a plurality of empty region grids fully inside the empty region and a plurality of boundary grids having at least a portion over the minimum spacing constraint region, the plurality of empty region grids and the plurality of boundary grids having a same size and aligned with the starting point; and

filling, by the processor, the empty region with a plurality of dummy fin cells by:

placing a standard dummy fin cell in each of the plurality of empty region grids; and

replacing the standard dummy fin cell in each of the plurality of empty region grids adjacent to the plurality of boundary grids with an expanded dummy fin cell, wherein the expanded dummy fin cell does not extend into the minimum spacing constraint region, and wherein the expanded dummy fin cell comprises a first portion in an empty region grid and a second portion in a boundary grid; and

implementing the IC layout in an IC.

8. The method of claim 7 , wherein filling the empty region comprises placing a standard dummy fin cell in each of the plurality of empty region grids, in the grid map, row by row.

9. The method of claim 7 , wherein filling the empty region comprises placing a standard dummy fin cell in each of the plurality of empty region grids, in the grid map, column by column.

10. The method of claim 7 , wherein filling the empty region comprises placing a standard dummy fin cell in each of the plurality of empty region grids, in the grid map, uni-directionally.

11. The method of claim 7 , wherein filling the empty region comprises placing a standard dummy fin cell in each of the plurality of empty region grids, in the grid map, bi-directionally.

12. The method of claim 7 , wherein filling the empty region comprises placing a standard dummy fin cell in each of the plurality of empty region grids, in the grid map, multi-directionally.

13. The method of claim 7 , wherein filling the empty region comprises placing a standard dummy fin cell in each of the plurality of empty region grids in the grid map in a spiral direction.

14. The method of claim 7 , wherein filling the empty region comprises placing a standard dummy fin cell in each of the plurality of empty region grids before replacing the standard dummy fin cell in each of the plurality of empty region grids adjacent to the plurality of boundary grids with an expanded dummy fin cell.

15. The method of claim 7 , wherein filling the empty region comprises replacing the standard dummy fin cell in each of a first portion of the plurality of empty region grids adjacent to the plurality of boundary grids with an expanded dummy fin cell before placing a standard dummy fin cell in each of a second portion of the plurality of empty region grids.

16. A method comprising:

identifying, by a processor, a first and a second empty region in an IC layout, wherein the IC layout comprises an active region comprising a fin array, and wherein the first and the second empty regions are separated from each other by the active region;

applying a first and a second grid map over the first and the second empty regions respectively, wherein the first and the second grid maps comprise a first and a second plurality of grids respectively;

filling the first and the second empty regions with a plurality of dummy fin cells by placing a dummy fin cell in each of the first and second plurality of grids; and

implementing the fin array and the plurality of dummy fin cells in an IC.

17. The method of claim 16 , wherein the first and second empty regions are separated from the active region by a minimum spacing.

18. The method of claim 16 , wherein the first and the second grid maps are aligned with a same point in the first or the second empty region.

19. The method of claim 16 , wherein the first and the second grid maps are aligned with a first and a second point in the first and second empty regions respectively, and wherein the first and the second grid maps are not aligned with each other.

20. The method of claim 16 , further comprising, after filling the first and second empty regions:

identifying gaps in the first and the second empty regions, wherein the first and the second grid maps overlay the gaps; and

replacing the dummy fin cells in grids adjacent to the gaps with expanded dummy fin cells, wherein the expanded dummy fin cells each comprise a first portion in a grid adjacent to a gap and a second portion filling the gap.