Model-based fill
View Patent ↗Various aspects of this disclosure relate to increasing pattern density in a circuit layout design of a circuit layer so as to control the thickness of material in a manufactured integrated circuit. For example, a layer in circuit design may be divided into separate areas, and a target thickness range may be established for all of the tiles in the integrated circuit design. Each area may be analyzed to determine if it has a sufficient pattern density for a thickness estimation model to accurately estimate its expected material thickness upon manufacture. Each tile may be analyzed to determine if the expected thickness for that tile is within the target thickness range.
1. A method, comprising:
identifying a target thickness for a portion of an integrated circuit design;
identifying at least one criterion for use in controlling addition of geometric elements to the portion of the integrated circuit design;
selecting a first potential geometric element shape from a plurality of available geometric element shapes;
based on the at least one criterion, determining one or more instances of the first potential geometric element shape to add to the portion of the integrated circuit design;
determining that adding the one or more instances of the first potential geometric element shape to the portion of the integrated circuit design would not result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness;
responsive to determining that adding the one or more instances of the first potential geometric element shape to the portion of the integrated circuit design would not result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness, selecting a second potential geometric element shape from the plurality of available geometric element shapes;
based on the at least one criterion, determining one or more instances of the second potential geometric element shape to add to the portion of the integrated circuit design;
determining that adding the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design would result in the portion of the integrated circuit design having a thickness that satisfies the target thickness; and
adding, by one or more computing devices, the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design.
2. The method of claim 1 , wherein the target thickness comprises a range of thickness values.
3. The method of claim 2 , further comprising:
determining that the portion of the integrated circuit design is outside the range of thickness values.
4. The method of claim 1 , wherein determining that adding the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design would result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness, includes:
estimating a value for a geometric element perimeter-to-area ratio that would result from adding the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design;
determining a thickness based on the value for the geometric element perimeter-to-area ratio; and
comparing the target thickness to the thickness.
5. The method of claim 4 , wherein determining the thickness includes:
determining the thickness from a lookup table using the value for the geometric element perimeter-to-area ratio and a value for each of the at least one criterion.
6. The method of claim 4 , wherein determining the thickness includes:
determining the thickness from a thickness estimation model using the value for the geometric element perimeter-to-area ratio and a value for each of the at least one criterion.
7. The method of claim 1 , wherein the at least one criterion includes a target geometric element density.
8. The method of claim 7 , wherein determining the one or more instances of the second potential geometric element shape to add to the portion of the integrated circuit design includes:
determining how many one or more instances of the second potential geometric element shape should be added to the portion of the integrated circuit design such that the target geometric element density is reached.
9. The method of claim 7 , further comprising:
selecting a specific value for the target geometric element density;
for each of the plurality of available geometric element shapes:
determining an amount to add to the portion of the integrated circuit design based on the specific value for the target geometric element density, and
determining that adding the amount to the portion of the integrated circuit design would not result in the portion of the integrated circuit design having an expected thickness that satisfies the target thickness;
selecting a different value for the target geometric element density; and
based on the different value for the target geometric element density, determining whether adding a particular geometric element shape to the portion of the integrated circuit design would result in the target thickness being satisfied.
10. An apparatus, comprising:
one or more processors;
memory storing executable instructions configured to, when executed by the one or more processors, cause the apparatus to:
identify a target thickness for a portion of an integrated circuit design;
identify at least one criterion for use in controlling addition of geometric elements to the portion of the integrated circuit design;
select a first potential geometric element shape from a plurality of available geometric element shapes;
based on the at least one criterion, determine a one or more instances of the first potential geometric element shape to add to the portion of the integrated circuit design;
determine that adding the one or more instances of the first potential geometric element shape to the portion of the integrated circuit design would not result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness;
responsive to determining that adding the one or more instances of the first potential geometric element shape to the portion of the integrated circuit design would not result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness, select a second potential geometric element shape from the plurality of available geometric element shapes;
based on the at least one criterion, determine a one or more instances of the second potential geometric element shape to add to the portion of the integrated circuit design;
determine that adding the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design would result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness; and
add the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design.
11. The apparatus of claim 10 , wherein determining that adding the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design would result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness, includes:
estimating a value for a geometric element perimeter-to-area ratio that would result from adding the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design;
determining a thickness based on the value for the geometric element perimeter-to-area ratio; and
comparing the target thickness to the thickness.
12. The apparatus of claim 10 , wherein the at least one criterion includes a target geometric element density.
13. The apparatus of claim 12 , wherein determining the one or more instances of the second potential geometric element shape to add to the portion of the integrated circuit design includes:
determining how many one or more instances of the potential geometric element shape should be added to the portion of the integrated circuit design such that the target geometric element density is reached.
14. The apparatus of claim 12 , wherein the memory further stores executable instructions configured to, when executed by the one or more processors, cause the apparatus to:
select a specific value for the target geometric element density;
for each of the plurality of available geometric element shapes:
determine an amount to add to the portion of the integrated circuit design based on the specific value for the target geometric element density, and
determine that adding the amount to the portion of the integrated circuit design would not result in the portion of the integrated circuit design having an expected thickness that satisfies the target thickness;
select a different value for the target geometric element density; and
based on the different value for the target geometric element density, determine whether adding a particular geometric element shape to the portion of the integrated circuit design would result in the target thickness being satisfied.
15. One or more computer readable storage devices, storing executable instructions configured to, when executed, cause an apparatus to:
identify a target thickness for a portion of an integrated circuit design;
identify at least one criterion for use in controlling addition of geometric elements to the portion of the integrated circuit design;
select a first potential geometric element shape from a plurality of available geometric element shapes;
based on the at least one criterion, determine one or more instances of the first potential geometric element shape to add to the portion of the integrated circuit design;
determine that adding the one or more instances of the first potential geometric element shape to the portion of the integrated circuit design would not result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness;
responsive to determining that adding the one or more instances of the first potential geometric element shape to the portion of the integrated circuit design would not result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness, select a second potential geometric element shape from the plurality of available geometric element shapes;
based on the at least one criterion, determine one or more instances of the second potential geometric element shape to add to the portion of the integrated circuit design;
determine that adding the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design would result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness; and
add the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design.
16. The one or more computer readable storage devices of claim 15 , wherein determining that adding the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design would result in the portion of the integrated circuit design having an estimated thickness that satisfies the target thickness, includes:
estimating a value for a geometric element perimeter-to-area ratio that would result from adding the one or more instances of the second potential geometric element shape to the portion of the integrated circuit design;
determining a thickness based on the value for the geometric element perimeter-to-area ratio; and
comparing the target thickness to the thickness.
17. The one or more computer readable storage devices of claim 15 , wherein the at least one criterion includes a target geometric element density.
18. The one or more computer readable storage devices of claim 15 , wherein the at least one criterion includes a target geometric element density, and wherein the one or more computer readable storage devices further stores executable instructions configured to, when executed, cause the apparatus to:
select a specific value for the target geometric element density;
for each of the plurality of available geometric element shapes:
determine an amount to add to the portion of the integrated circuit design based on the specific value for the target geometric element density, and
determine that adding the amount to the portion of the integrated circuit design would not result in the portion of the integrated circuit design having an expected thickness that satisfies the target thickness;
select a different value for the target geometric element density; and
based on the different value for the target geometric element density, determine whether adding a particular geometric element shape to the portion of the integrated circuit design would result in the target thickness being satisfied.