Methods for forming a semiconductor arrangement of fins having multiple heights and an alignment mark
Among other things, one or semiconductor arrangements, and techniques for forming such semiconductor arrangements are provided. An etch sequence is performed to form a first etched region over a planar region of a semiconductor arrangement. The first etched region exposes a planar structure, such as an alignment mark used for alignment during semiconductor fabrication. The etch sequence forms a second etched region over a semiconductor fin region of the semiconductor arrangement. In an embodiment, the etch sequence forms a first trench, a first fin nub and a first pillar in the semiconductor fin region, where the first trench is formed in a semiconductor substrate of the semiconductor fin region. A multi-depth STI structure is formed over at least one of the first trench, the first fin nub, or the first pillar.
1. A method for forming a semiconductor arrangement, comprising:
forming a first semiconductor fin protruding from a substrate and having a first height;
forming a first semiconductor fin nub protruding from the substrate and having a second height less than the first height;
forming an alignment mark overlying the substrate;
forming a first trench in the substrate; and
forming a first dielectric layer in the first trench to contact a sidewall of the substrate and over the substrate to contact a sidewall of the first semiconductor fin, a sidewall of the first semiconductor fin nub, and a sidewall of the alignment mark.
2. The method of claim 1 , wherein forming the first trench comprises etching the substrate between the first semiconductor fin and the first semiconductor fin nub.
3. The method of claim 1 , comprising forming a second trench in the alignment mark concurrently with forming the first trench.
4. The method of claim 1 , comprising:
forming a first semiconductor pillar having a third height less than the first height and greater than the second height between the first semiconductor fin and the first semiconductor fin nub, wherein forming the first dielectric layer comprises forming the first dielectric layer to contact a sidewall of the first semiconductor pillar.
5. The method of claim 1 , comprising:
forming a gate structure over the first semiconductor fin and adjacent the sidewall of the first semiconductor fin after forming the first dielectric layer.
6. The method of claim 1 , wherein forming the first dielectric layer comprises forming the first dielectric layer over a top surface of the first semiconductor fin nub.
7. The method of claim 6 , wherein a portion of the first semiconductor fin is exposed over the first dielectric layer.
8. The method of claim 7 , comprising:
forming a gate structure over the portion of the first semiconductor fin.
9. The method of claim 7 , comprising forming a second dielectric layer over the portion of the first semiconductor fin, wherein the second dielectric layer contacts the first dielectric layer.
10. The method of claim 1 , comprising:
forming a second trench in the alignment mark, wherein forming the first dielectric layer comprises forming the first dielectric layer in the second trench.
11. A method for forming a semiconductor arrangement, comprising:
forming a first semiconductor fin protruding from a substrate and having a first height;
forming a first semiconductor fin nub protruding from the substrate and having a second height less than the first height;
forming an alignment mark over the substrate;
forming a first trench in the substrate; and
forming a dielectric layer adjacent the first semiconductor fin, contacting a top surface of the first semiconductor fin nub and a sidewall of the alignment mark, and in the first trench such that the dielectric layer extends below a bottom surface of the first semiconductor fin and a bottom surface of the first semiconductor fin nub.
12. The method of claim 11 , comprising:
forming a second trench in the alignment mark, wherein forming the dielectric layer comprises forming the dielectric layer in the second trench.
13. The method of claim 12 , wherein forming the second trench comprises forming the second trench concurrently with forming the first trench.
14. The method of claim 11 , wherein a portion of the first semiconductor fin is exposed over the dielectric layer.
15. The method of claim 14 , comprising:
forming a gate structure over the portion of the first semiconductor fin.
16. A method for forming a semiconductor arrangement, comprising:
forming a first semiconductor fin protruding from a substrate and having a first height;
forming a first semiconductor fin nub protruding from the substrate and having a second height less than the first height;
forming an alignment mark over the substrate;
forming a first trench in the substrate;
forming a second trench in the alignment mark; and
forming a dielectric layer adjacent the first semiconductor fin, contacting a top surface of the first semiconductor fin nub, in the second trench, and in the first trench such that the dielectric layer extends below a bottom surface of the first semiconductor fin and a bottom surface of the first semiconductor fin nub.
17. The method of claim 16 , wherein forming the second trench comprises forming the second trench concurrently with forming the first trench.
18. The method of claim 16 , wherein a portion of the first semiconductor fin is exposed over the dielectric layer.
19. The method of claim 18 , comprising:
forming a gate structure over the portion of the first semiconductor fin.
20. The method of claim 16 , comprising:
forming a first semiconductor pillar protruding from the substrate and having a third height less than the first height and more than the second height, wherein:
forming the first trench comprises forming the first trench between the first semiconductor pillar and the first semiconductor fin nub, and
forming the dielectric layer comprises forming the dielectric layer to overlie a top surface of the first semiconductor pillar.