Oxide definition (OD) gradient reduced semiconductor device and method of making

A method, comprising:

• computing oxide definition (OD) density in insertion regions from OD density information corresponding to a placed layout of an integrated circuit (IC);
• performing three dimensional (3D) smoothing on the insertion regions to identify at least one low OD density region and at least one high OD density region;
• identifying a first high OD dummy cell having an OD higher than the low OD density region and adding the first high OD dummy cell to the low OD density region;
• and
• identifying a first low OD dummy cell having an OD lower than the high OD density region and adding the first low OD dummy cell to the high OD density region;
• dividing the high OD density region or the low OD density region into at least two sub-regions;
• identifying each of the sub-regions of the at least two sub-regions as a high density sub-region or a low density sub-region;
• adding at least one second high density dummy cell to the low density sub-region;
• and
• adding at least one second low density dummy cell to the high density sub-region.

A method of reducing an oxide definition (OD) density gradient between a first region and a second region of an integrated circuit (IC), the method comprising:

• a first smoothing pass, the first smoothing pass comprising:
• identifying the first region as a high density region and the second region as a low density region based on a determination that the first region has an OD density greater than an OD density of the second region;
• adding at least one first high density dummy cell of a first set of first high density dummy cells to the low density region, the at least one first high density dummy cell of the first set of first high density dummy cells having an OD density greater than the OD density of the second region;
• and
• adding at least one first low density dummy cell of a first set of first low density dummy cells to the high density region, the at least one first low density dummy cell of the first set of first low density dummy cells having an OD density less than the OD density of the first region;
• and
• a second smoothing pass, the second smoothing pass comprising:
• dividing the first region into an array of sub-regions;
• identifying the sub-regions included in the array of sub-regions as high density sub-regions and low density sub-regions;
• adding at least one second high density dummy cell of a second set of second high density dummy cells to at least one of the low density sub-regions, the at least one second high density dummy cell of the second set of second high density dummy cells having an OD density greater than the OD density of the at least one low density sub-region;
• and
• adding at least one second low density dummy cells of a second set of second low density dummy cells to at least one of the high density sub-regions, the at least one second low density dummy cell of the second set of second low density dummy cells having an OD density less than the OD density of the at least one high density sub-region.