HDP-CVD dep/etch/dep process for improved deposition into high aspect ratio features

A method of depositing a silica glass film on a substrate disposed in a substrate processing chamber, the method comprising, in order:

• flowing a first process gas comprising silane and oxygen into the processing chamber and forming a high density plasma from the first process gas to deposit a first portion of the silica glass film over the substrate;
• stopping deposition of the silica glass film and flowing a fluorine etchant into the process chamber to etch part of the first portion of the silica glass film;
• flowing a passivation gas comprising oxygen into the processing chamber;
• and
• flowing a second process gas comprising silane and oxygen into the processing chamber to deposit a second portion of the silica glass film over the first portion;
• wherein the high density plasma is continuously maintained during each of the above steps.

A method of depositing a silica glass film on a substrate disposed in a substrate processing chamber, the method comprising:

• forming a high density plasma within the substrate processing chamber to heat the substrate to a temperature of at least 400° C. prior to depositing the silica glass film on the substrate;
• maintaining the high density plasma while (i) flowing a first process gas comprising a silicon source and an oxygen source into the processing chamber to deposit a first portion of the silica glass film over the substrate, (ii) flowing a fluorine-containing etchant gas into the process chamber to etch part of the first portion of the silica glass film;
• (iii) flowing a passivation gas comprising oxygen into the processing chamber and (iv) flowing a second process gas comprising silane and oxygen into the processing chamber to deposit a second portion of the silica glass film over the first portion;
• wherein RF bias power is applied to the chamber during deposition of the first portion of the film, stopped prior to etching the part of the first portion of the film and then again applied prior to deposition of the second portion of the film.

A method of depositing a silica glass film on a substrate disposed in a substrate processing chamber, the method comprising:

• flowing an inert gas into the substrate processing chamber;
• forming a high density plasma within the substrate processing chamber from the inert gas;
• adding a flow of oxygen to the plasma and heating the substrate to a temperature of at least 400° C. prior to depositing the silica glass film on the substrate;
• adding a flow of silane to the plasma to deposit a first portion of the silica glass film over the substrate, wherein RE bias power is applied to the chamber during deposition of the first portion of the film;
• stopping the flow of silane and adding a flow of a fluorine-containing etchant to the plasma to etch part of the first portion of the silica glass film, wherein RF bias power is stopped prior to etching the part of the first portion of the film;
• stopping the flow of the fluorine-containing etchant and exposing the surface of the substrate to a oxygen plasma for between 5 and 20 seconds, wherein RE bias power is applied during passivation of the upper surface;
• adding a flow of silane to the plasma to deposit a second portion of the silica glass film over the first portion, wherein RE bias power is applied during deposition of the second portion of the film.

A method of filling a gap formed between adjacent raised surfaces on a substrate with a silica glass film, the method comprising:

• transferring the substrate into a high density plasma CVD substrate processing chamber;
• partially filling the gap by depositing a first portion of the silica glass film over the substrate by flowing a first process gas comprising silicon and oxygen into the processing chamber and forming a high density plasma from the first process gas;
• etching the first portion of the silica glass film by flowing an etchant gas comprising a fluorine etchant into the process chamber and forming a high density plasma from the etchant gas;
• thereafter, exposing the first portion of the silica glass film to a high density plasma formed from a passivation gas comprising oxygen introduced into the processing chamber;
• and
• thereafter, filling the gap by depositing a second portion of the silica glass film over the first portion by flowing a second process gas comprising silicon and oxygen into the processing chamber and forming a high density plasma from the second process gas.