High voltage device
Semiconductor devices and methods are provided. A semiconductor device according to the present disclosure includes a substrate having a first area and a second area, a plurality of fin structures extending along a direction over the first area and the second area of the substrate, a first transistor and a second transistor in the first area, a first isolation structure disposed between the first transistor and the second transistor, a first isolation structure disposed between the first transistor and the second transistor, a third transistor and a fourth transistor in the second area, and a second isolation structure disposed between the third transistor and the fourth transistor. The first isolation structure includes a first width along the direction and the second isolation structure includes a second width along the direction. The second width is greater than the first width.
1. A method, comprising:
forming a plurality of fin structures over a substrate, the plurality of fin structures extending lengthwise along a first direction over a first area and a second area of the substrate, the first direction being extending along a top surface of the substrate;
forming a first fin cut trench through more than one of the plurality of the fin structures in the first area;
forming a second fin cut trench through more than one of the plurality of fin structures in the second area;
depositing a dielectric material in the first fin cut trench and the second fin cut trench to form a first isolation feature and a second isolation feature, respectively; and
forming a first isolation gate structure directly over a top surface of the first isolation feature and a second isolation gate structure directly over a top surface of the second isolation feature,
wherein the first fin cut trench includes a first width along the first direction and the second fin cut trench includes a second width along the first direction,
wherein the forming of the first isolation gate structure and the second isolation gate structure comprises:
forming a first dummy gate stack over the first isolation feature;
forming a second dummy gate stack over the second isolation feature;
replacing the first dummy gate stack with a first isolation gate structure; and
replacing the second dummy gate stack with a second isolation gate structure wherein a ratio of the second width to the first width is between 3 and 30.
2. The method of claim 1 ,
wherein the plurality of fin structures extend in parallel along the first direction and are spaced apart from one another along a second direction perpendicular to the first direction,
wherein the first fin cut trench and the second fin cut trench extend lengthwise along the second direction.
3. The method of claim 1 , further comprising:
forming a first gate structure over the plurality of fin structures in the first area; and
forming a second gate structure over the plurality of fin structures in the second area,
wherein the first gate structure includes a third width,
wherein the second gate structure includes a fourth width,
wherein a ratio of the fourth width to the third width is between about 15 and about 400.
4. The method of claim 1 ,
wherein the first fin cut trench includes a first depth,
wherein the second fin cut trench includes a second depth,
wherein the first depth is substantially equal to the second depth.
5. The method of claim 1 , wherein the forming of the first fin cut trench comprises:
depositing a material layer over the substrate and the plurality of fin structures;
depositing a first photoresist layer over the material layer;
exposing the first photoresist layer using a first radiation source;
developing the exposed first photoresist layer to form a first photoresist pattern; and
etching the material layer and the plurality of fin structures in the first area using the first photoresist pattern as an etch mask.
6. The method of claim 5 ,
wherein the forming of the second fin cut trench comprises:
depositing a second photoresist layer over the material layer,
exposing the second photoresist layer using a second radiation source,
developing the exposed second photoresist layer to form a second photoresist pattern, and
etching the material layer and the plurality of fin structures in the second area using the second photoresist pattern as an etch mask,
wherein a wavelength of the first radiation source is smaller than a wavelength of the second radiation source.
7. The method of claim 6 , wherein a composition of the first photoresist layer is different from a composition of the second photoresist layer.
8. The method of claim 6 ,
wherein the wavelength of the first radiation source is about 193 nm,
wherein the wavelength of the second radiation source is about 248 nm.
9. A method, comprising:
receiving a workpiece comprising a plurality of fin structures extending continuously along a first direction over a first area and a second area;
forming a first patterned photoresist layer over the workpiece;
etching the workpiece using the first patterned photoresist layer as an etch mask to form a first fin cut trench in the first area, the first fin cut trench extending lengthwise along a second direction perpendicular to the first direction and comprising a first trench width along the first direction;
forming a second patterned photoresist layer over the workpiece, including over the first fin cut trench;
etching the workpiece using the second patterned photoresist layer as an etch mask to form a second fin cut trench in the second area, the second fin cut trench extending lengthwise along the second direction and comprising a second trench width along the first direction;
forming a first isolation feature in the first fin cut trench and a second isolation feature in the second fin cut trench;
forming a first dummy gate stack directly over the first isolation feature and a second dummy gate stack over a first channel region of the plurality of fin structures in the first area;
forming a third dummy gate stack directly over the second isolation feature and a fourth dummy gate stack over a second channel region of the plurality of fin structures in the second area; and
replacing the first dummy gate stack, the second dummy gate stack, the third dummy gate stack, and the fourth dummy gate stack with a first gate structure, a first isolation gate structure, a second gate structure, and a second isolation gate structure, respectively,
wherein, along the first direction, the first dummy gate stack comprises a first width, the second dummy gate stack comprises a second width, the third dummy gate stack comprises a third width, and the fourth dummy gate stack comprises a fourth width,
wherein the fourth width is greater than the second width,
wherein a ratio of the second trench width to the first trench width is between 3 and 30.
10. The method of claim 9 , wherein the third width is greater than the first width.
11. The method of claim 9 , wherein the first width is greater than the second width.
12. The method of claim 9 , wherein the fourth width is greater than the third width.
13. The method of claim 9 ,
wherein the first isolation feature comprises a first depth,
wherein the second isolation feature comprises a second depth,
wherein the first depth is substantially similar to the second depth.
14. The method of claim 9 ,
wherein the forming of the first patterned photoresist layer comprises use of a first radiation source,
wherein the forming of the second patterned photoresist layer comprises use of a second radiation source,
wherein a first wavelength of the first radiation source is smaller than a second wavelength of the second radiation source.
15. A method, comprising:
receiving a workpiece comprising a plurality of fin structures extending continuously along a first direction over a first area and a second area;
forming a first patterned photoresist layer over the workpiece;
etching the workpiece using the first patterned photoresist layer as an etch mask to form a first fin cut trench in the first area, the first fin cut trench extending lengthwise along a second direction perpendicular to the first direction;
forming a second patterned photoresist layer over the workpiece;
etching the workpiece using the second patterned photoresist layer as an etch mask to form a second fin cut trench in the second area, the second fin cut trench extending lengthwise along the second direction;
forming a first isolation feature in the first fin cut trench and a second isolation feature in the second fin cut trench;
forming a first dummy gate stack directly over the first isolation feature and a second dummy gate stack over a first channel region of the plurality of fin structures in the first area;
forming a third dummy gate stack directly over the second isolation feature and a fourth dummy gate stack over a second channel region of the plurality of fin structures in the second area; and
replacing the first dummy gate stack, the second dummy gate stack, the third dummy gate stack, and the fourth dummy gate stack with a first gate structure, a first isolation gate structure, a second gate structure, and a second isolation gate structure, respectively,
wherein the first fin cut trench comprises a first width along the first direction,
wherein the second fin cut trench comprises a second width along the first direction,
wherein a ratio of the second width to the first width is between 3 and 30.
16. The method of claim 15 ,
wherein the first dummy gate stack comprises a first gate length along the first direction,
wherein the second dummy gate stack comprises a second gate length along the first direction,
wherein the first gate length corresponds to the first width,
wherein the second gate length corresponds to the second width.
17. The method of claim 15 ,
wherein the first width is between about 10 nm and about 35 nm,
wherein the second width is between about 100 nm and about 300 nm.
18. The method of claim 15 , wherein a composition of the first patterned photoresist layer is different from a composition of the second patterned photoresist layer.
19. The method of claim 15 ,
wherein the forming of the first patterned photoresist layer comprises use of a first radiation source,
wherein the forming of the second patterned photoresist layer comprises use of a second radiation source,
wherein a first wavelength of the first radiation source is smaller than a second wavelength of the second radiation source.
20. The method of claim 19 , wherein the first wavelength is about 193 nm and the second wavelength is about 248 nm.