Semiconductor devices and methods of manufacturing thereof

1. A semiconductor device, comprising:

a substrate including a first area and a second area;

wherein the semiconductor device in the first area comprises:

a plurality of first non-planar semiconductor structures, wherein the first non-planar semiconductor structures, parallel with one another, are separated with a first distance; and

a first isolation region comprising a first layer and a second layer that collectively embed a lower portion of each of the first non-planar semiconductor structures, wherein at least one of the first layer or second layer of the first isolation region is in a cured state; and

wherein the semiconductor device in the second area comprises:

a plurality of second non-planar semiconductor structures, wherein the second non-planar semiconductor structures, parallel with one another, are separated with a second distance; and

a second isolation region comprising a first layer and a second layer that collectively embed a lower portion of each of the second non-planar semiconductor structures, wherein at least one of the first or second layer of the second isolation region is in a cured state.

2. The semiconductor device of claim 1 , wherein the first distance is less than the second distance.

3. The semiconductor device of claim 2 , wherein a first height of a non-embedded, upper portion of each of the first non-planar semiconductor structures is equal to a second height of a non-embedded, upper portion of each of the second non-planar semiconductor structures.

4. The semiconductor device of claim 1 , wherein each of the first non-planar semiconductor structures comprises a plurality of first channel layers vertically separated from one another, and each of the second non-planar semiconductor structures comprises a plurality of second channel layers vertically separated from one another.

5. The semiconductor device of claim 1 , wherein the one of the first and second layers of the first isolation region that is in the cured state is disposed above the other one of first and second layers of the first isolation region that is in the uncured state, and the one of the first and second layers of the second isolation region that is in the cured state is disposed above the other one of first and second layers of the second isolation region that is in the uncured state.

6. The semiconductor device of claim 1 , further comprising:

a first active gate structure over a non-embedded, upper portion of each of the first non-planar semiconductor structures; and

a second active gate structure over a non-embedded, upper portion of each of the second non-planar semiconductor structures.

7. The semiconductor device of claim 1 , wherein the one of the first and second layers of the first isolation region that is in the cured state has a higher density than the other one of first and second layers of the first isolation region that is in the uncured state, and the one of the first and second layers of the second isolation region that is in the cured state has a higher density than the other one of first and second layers of the second isolation region that is in the uncured state.

8. The semiconductor device of claim 1 , wherein the first isolation region further comprises a third layer, together with the first and second layers of the first isolation region, that collectively embed the lower portion of each of the first non-planar semiconductor structures, and the second isolation region further comprises a third layer, together with the first and second layers of the second isolation region, that collectively embed the lower portion of each of the second non-planar semiconductor structures.

9. The semiconductor device of claim 8 , wherein the third layer of the first isolation region is in an uncured state and disposed below the first and second layers of the first isolation region, and the third layer of the second isolation region is in a uncured state and disposed below the first and second layers of the second isolation region.

10. The semiconductor device of claim 8 , wherein the third layer of the first isolation region is in the cured state and disposed above one of the first and second layers of the first isolation region that is in a uncured state, and the third layer of the second isolation region is in the cured state and disposed above one of the first and second layers of the second isolation region that is in a uncured state.