Patent ID: 7939419

Claim:
A method of filling a trench, comprising: providing a substrate having an upper surface, and a trench extending therein from the upper surface; forming a deposition layer of high-density plasma oxide on the upper surface of and within the trench of the substrate, including by inducing a reaction of oxygen and SiH 4 using plasma; removing high-density plasma oxide from at least one of the upper surface of the substrate and the periphery of an upper part of the trench, including by inducing a reaction of NF 3 gas and oxygen using plasma; and subsequently removing high-density plasma oxide from sides of the trench, and simultaneously building up the deposition layer on the bottom of the trench with high-density plasma oxide, including by using a combination of NF 3 , oxygen and SiH 4 and inducing a reaction of the oxygen and the SiH 4 using plasma; wherein the forming of the deposition layer comprises forming a first high-density plasma oxide layer on the substrate, by inducing the reaction of oxygen and SiH 4 using plasma, subsequently adding NF 3 to oxygen and SiH 4 , and etching the first high-density plasma oxide layer from sides of the trench using the NF 3 , and simultaneously forming a second high-density plasma oxide layer on the first high-density plasma oxide layer by inducing a reaction of oxygen and SiH 4 using plasma, whereby the subsequent removing of high-density plasma oxide from sides of the trench, and the simultaneous building up of the deposition layer on the bottom of the trench forms a third high-density plasma oxide, and wherein the inducing of the reaction to form the second high-density plasma oxide layer or the third high-density plasma oxide layer comprises forming plasma from hydrogen.