Method of forming shallow trench isolation structure

1. A method of forming a shallow trench isolation structure, comprising:

providing a substrate comprising a top surface;

forming a trench extending from the top surface into the substrate, wherein the trench has sidewalls and a bottom surface;

forming a liner oxide layer on the sidewalls and the bottom surface;

causing fluorine radicals to adhere on the liner oxide layer by treating the liner oxide layer in a plasma environment comprising at least one of NF 3 , F 2 , and BF 2 ; and

filling the trench with a dielectric material over the liner oxide layer and the fluorine radicals adhered to the liner oxide layer.

2. The method of claim 1 , wherein the plasma environment comprises NF 3 .

3. The method of claim 2 , wherein the NF 3 comprises a flow rate, the flow rate is in the range of about 50 standard cubic centimeters per minute (sccm) to about 500 sccm.

4. The method of claim 1 , wherein the first plasma environment further comprises a carrier gas selected from a group consisting of H 2 , He, N 2 , Ne, Ar, Kr, Xe, and Rn.

5. The method of claim 4 , wherein the carrier gas is H 2 or Ne.

6. The method of claim 5 , wherein the carrier gas is H 2 , and a flow rate of H 2 is the range of about 50 sccm to about 1000 sccm.

7. The method of claim 5 , wherein the carrier gas is He, and a flow rate of He is the range of about 50 sccm to about 1000 sccm.

8. The method of claim 1 , wherein the dielectric material comprise silicon oxide, silicon nitride, silicon oxynitride, or fluoride-doped silicate glass (FSG).

9. A method of forming a shallow trench isolation structure, comprising:

providing a substrate comprising a top surface;

forming a trench extending from the top surface into the substrate, wherein the trench has sidewalls and a bottom surface;

forming a liner oxide layer on the sidewalls and the bottom surface in a first process chamber;

performing a plasma treatment in an environment comprising NF 3 in a second process chamber without the substrate to generate fluorine radicals in the second process chamber;

after the plasma treatment, placing the substrate into the second process chamber;

causing the fluorine radicals in the second process chamber to defuse into the liner oxide layer; and

filling the trench with a dielectric layer, over the liner oxide layer and the fluorine radicals defused into the liner oxide layer, in the second process chamber after the plasma treatment.

10. The method of claim 9 , wherein the NF 3 has a flow rate of about 500 to about 600 sccm.

11. The method of claim 9 , wherein the plasma treatment has an operation power in a range of about 2000 W to about 10000 W.