	US 12,444,601 B2
	Semiconductor device and method of forming thereof
Han-Pin Chung, Fongshan (TW); and Chi-Kang Liu, Taipei (TW)
Assigned to Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed on Jul. 15, 2020, as Appl. No. 16/929,556.
Claims priority of provisional application 62/966,755, filed on Jan. 28, 2020.
Prior Publication US 2021/0233764 A1, Jul. 29, 2021
Int. Cl. H01L 21/02 (2006.01); H10D 30/01 (2025.01); H10D 30/62 (2025.01); H10D 84/01 (2025.01); H10D 84/03 (2025.01)

CPC H01L 21/0223 (2013.01) [H01L 21/02348 (2013.01); H10D 30/0243 (2025.01); H10D 30/62 (2025.01); H10D 84/0158 (2025.01); H10D 84/038 (2025.01)]

20 Claims

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

forming a flowable dielectric material on a sidewall of a semiconductor fin;

performing an ozone (O₃) cure on the flowable dielectric material;

performing an ultraviolet (UV) cure on the flowable dielectric material after performing the O₃cure on the flowable dielectric material;

performing a first cycle of a conversion process, wherein the first cycle of the conversion process induces oxidation on a first sidewall of the semiconductor fin, and where the first cycle of the conversion process comprises:

performing a first wet oxidation treatment on the flowable dielectric material after performing the UV cure on the flowable dielectric material, the first wet oxidation treatment comprising applying an acid and oxidizer mixture on the flowable dielectric material at 170° C., wherein the acid and oxidizer mixture comprises a mixture of H₂SO₄and H₂O₂, and wherein the acid and oxidizer mixture has a molarity in a range of 2 M to 18.4 M;

performing a first dry anneal on the flowable dielectric material to cure the flowable dielectric material and form an insulation material, wherein the first dry anneal is performed with a volume percentage of H₂O greater than 0%, and wherein a top surface of the insulation material comprises silicon and oxygen, and a degree of oxidation of the insulation material decreases in proportion to a distance from the top surface of the insulation material;

performing a second cycle of the conversion process, wherein the second cycle of the conversion process induces no additional oxidation on the first sidewall of the semiconductor fin, and where the second cycle of the conversion process comprises:

performing a second wet oxidation treatment on the flowable dielectric material, the second wet oxidation treatment comprising applying the acid and oxidizer mixture on the flowable dielectric material at 170° C.;

performing a second dry anneal on the flowable dielectric material, wherein the second dry anneal is performed with a volume percentage of H₂O greater than 0%; and

forming a dummy gate over the insulation material.

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

depositing a flowable dielectric material on a sidewall of a semiconductor fin;

performing an ozone (O₃) cure on the flowable dielectric material, wherein the flowable dielectric material comprises silicon-hydrogen bonds and silicon-nitrogen bonds;

performing an ultraviolet (UV) cure on the flowable dielectric material after performing the O₃cure on the flowable dielectric material;

performing a first cycle of a conversion process to convert the flowable dielectric material to an oxide after performing the UV cure on the flowable dielectric material, wherein performing the first cycle of the conversion process breaks the silicon-hydrogen bonds and the silicon-nitrogen bonds of the flowable dielectric material and establishes silicon-oxygen bonds of the oxide, and wherein the first cycle of the conversion process oxidizes the sidewall of the semiconductor fin, the first cycle of the conversion process comprising:

applying a first acid mixture to the flowable dielectric material at 170° C., wherein the first acid mixture comprises H₂SO₄and H₂O₂with a molarity in a range of 2 M to 18.4 M; and

annealing the flowable dielectric material with a first dry anneal with a volume percentage of H₂O less than 10% and greater than 0%;

performing a second cycle of the conversion process to further convert the flowable dielectric material to the oxide after performing the first cycle of the conversion process, wherein performing the second cycle of the conversion process is free of further oxidizing the sidewall of the semiconductor fin, the second cycle of the conversion process comprising:

applying a second acid mixture to the flowable dielectric material at 170° C., wherein the second acid mixture comprises H₂SO₄and H₂O₂with a molarity in a range of 2 M to 18.4 M; and

annealing the flowable dielectric material with a second dry anneal with a volume percentage of H₂O less than 10% and greater than 0%; and

recessing the oxide to form a shallow trench isolation region.

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

depositing a first dielectric material between a first fin and a second fin;

performing an ozone cure on the first dielectric material;

performing an ultraviolet cure on the first dielectric material after performing the ozone cure on the first dielectric material;

performing a first cycle of a conversion process for converting the first dielectric material to an oxide after performing the ultraviolet cure on the first dielectric material, wherein the first cycle of the conversion process induces oxidation on sidewalls of the first fin and the second fin, the first cycle of the conversion process comprising:

applying a first sulfuric acid-hydrogen peroxide mixture to the first dielectric material at 170° C., wherein the first sulfuric acid-hydrogen peroxide mixture has a molarity in a range of 2 M to 18.4 M; and

performing a first dry anneal on the first dielectric material;

performing a second cycle of the conversion process without inducing additional oxidation on the sidewalls of the first fin and the second fin, the second cycle of the conversion process comprising:

applying a second sulfuric acid-hydrogen peroxide mixture to the first dielectric material at 170° C., wherein the second sulfuric acid-hydrogen peroxide mixture has a molarity in a range of 2 M to 18.4 M; and

performing a second dry anneal on the first dielectric material;

removing an excess portion of the oxide above the first fin and the second fin with a planarization; and

recessing the oxide to form a shallow trench isolation region between the first fin and the second fin.