Selective removal of semiconductor fins
View Patent ↗An array of semiconductor fins is formed on a top surface of a substrate. A dielectric material liner is formed on the surfaces of the array of semiconductor fins. A photoresist layer is applied and patterned such that sidewalls of an opening in the photoresist layer are parallel to the lengthwise direction of the semiconductor fins, and are asymmetrically laterally offset from a lengthwise direction passing through the center of mass of a semiconductor fin to be subsequently removed. An angled ion implantation is performed to convert a top portion of dielectric material liner into a compound material portion. The compound material portion is removed selective to the remaining dielectric material liner, and the physically exposed semiconductor fin can be removed by an etch or converted into a dielectric material portion by a conversion process. The dielectric material liner can be removed after removal of the semiconductor fin.
1. A semiconductor structure comprising:
a plurality of semiconductor fins located on a substrate, each of said plurality of semiconductor fins having a parallel pair of semiconductor sidewalls that are laterally spaced from each other by a uniform fin width;
at least one dielectric material portion located between, and spaced apart from, adjacent semiconductor fins in said plurality of semiconductor fins, said at least one dielectric material portion having a parallel pair of dielectric sidewalls that are parallel to said parallel pairs of semiconductor sidewalls, wherein a bottom surface of said at least one dielectric material portion adjoining said parallel pair of dielectric sidewalls has a same width as said uniform fin width;
a shallow trench isolation layer laterally surrounding said at least one dielectric material portion and a lower portion of each of said plurality of semiconductor fins; and
a semiconductor material portion located beneath one of said at least one dielectric material portion, said semiconductor material portion having a width that is the same as said uniform fin width and a width of said at least one dielectric material portion.
2. The semiconductor structure of claim 1 , wherein an upper sub-portion of said at least one dielectric material portion has a greater width than said uniform fin width.
3. The semiconductor structure of claim 1 , wherein said plurality of semiconductor fins includes at least two semiconductor fins that constitute a one-dimensional array having a uniform pitch along a direction perpendicular to said parallel pairs of semiconductor sidewalls, and a lateral distance between a semiconductor sidewall of one of said at least two semiconductor fins and one of said parallel pair of dielectric sidewalls is the same as said uniform pitch.
4. The semiconductor structure of claim 1 , further comprising:
a gate dielectric contacting top and sidewall surfaces of said plurality of semiconductor fins and contacting top and sidewall surfaces of said at least one dielectric material portion; and
a gate electrode contacting said gate dielectric.
5. The semiconductor structure of claim 1 , wherein a vertical cross-sectional shape of said at least one dielectric material portion along a vertical plane perpendicular to said parallel pair of dielectric sidewalls is asymmetric.
6. The semiconductor structure of claim 1 , wherein said at least one dielectric material portion protrudes farther upward from a top surface of said substrate than a topmost portion of said plurality of semiconductor fins.
7. The semiconductor structure of claim 1 , wherein a topmost surface of said at least one dielectric material portion is coplanar with a top surface of said shallow trench isolation layer.
8. The semiconductor structure of claim 1 , wherein a bottommost surface of said at least one dielectric material portion is vertically offset from a horizontal plane including a planar bottom surface of said shallow trench isolation layer.
9. The semiconductor structure of claim 1 , further comprising a dielectric liner contacting a top surface of said substrate, lower portions of said parallel pairs of semiconductor sidewalls, and said parallel pair of dielectric sidewalls.
10. The semiconductor structure of claim 1 , wherein said at least one dielectric material portion extends below a top surface of said substrate and below a horizontal plane including a planar bottom surface of said shallow trench isolation layer.
11. The semiconductor structure of claim 1 , wherein said semiconductor material portion has a bottom surface that is coplanar with a horizontal plane including a planar bottom surface of said shallow trench isolation layer.
12. The semiconductor structure of claim 1 , wherein said semiconductor material portion comprises a semiconductor material the same as said plurality of semiconductor fins.
13. The semiconductor structure of claim 1 , wherein a gap is present between said at least one dielectric material portion and each of said adjacent semiconductor fins.