Shallow trench isolation forming method and structures resulting therefrom

A method of forming a semiconductor device, the method comprising:

• patterning a first region of a semiconductor substrate to form a first plurality of fins in the first region;
• patterning a second region of the semiconductor substrate to form a second plurality of fins in the second region, wherein a first width between adjacent fins of the first plurality of fins is larger than a second width between adjacent fins of the second plurality of fins;
• depositing a first dielectric material over the first plurality of fins and the second plurality of fins, wherein the first dielectric material spans the first width between the adjacent fins of the first plurality of fins and spans the second width between the adjacent fins of the second plurality of fins;
• converting the first dielectric material to a second dielectric material, wherein a first rate of conversion of the first dielectric material between the adjacent fins of the first plurality of fins is higher than a second rate of conversion of the first dielectric material between the adjacent fins of the second plurality of fins.

A method of forming a semiconductor device, the method comprising:

• forming a first plurality of fins in a first region of a substrate, wherein the first plurality of fins have a first fin density;
• forming a second plurality of fins in a second region of the substrate, wherein the second plurality of fins have a second fin density that is greater than the first fin density;
• filling a first recess between adjacent fins of the first plurality of fins with a first dielectric material;
• filling a second recess between adjacent fins of the second plurality of fins with the first dielectric material;
• and
• converting the first dielectric material in the first recess and the second recess to a second dielectric material, wherein during converting the first dielectric material, a first conversion rate of the first dielectric material in the first recess is greater than a second conversion rate of the first dielectric material in the second recess.