Post-deposition treatment to enhance properties of Si-O-C low k films

• US 7,326,657 B2
• Filed: 11/15/2004
• Issued: 02/05/2008
• Est. Priority Date: 08/17/1999
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Xia, Li-Qun, Lim, Tian H., Gaillard, Frederic, Yieh, Ellie
• Primary Examiner(s): Loke; Steven
• Assistant Examiner(s): GOODWIN, DAVID J
• Application Number:
  US10/990,251
• Publication Number:
  US 20050070128A1
• Time in Patent Office: 1,177 Days
• Field of Search: 438/778, 438/787, 438/790
• US Class Current: 438/790
• CPC Class Codes: C23C 16/0218 in a reactive atmosphere C23C16/0227 takes precedence
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02071 the processing being a delineation, e.g. RIE, of conductive layers
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02312 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/02362 formation of intermediate layers, e.g. capping layers or diffusion barriers
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/3146 Carbon layers, e.g. diamond-like layers
• CPC Class Codes: H01L 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/76807 for dual damascene structures
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76837 : Filling up the space between adjacent conductive structures; Gap-filling properties of dielectrics
• CPC Class Codes: Y10S 438/931 : Silicon carbide semiconductor

Abstract

A method for providing a dielectric film having enhanced adhesion and stability. The method includes a post deposition treatment that densifies the film in a reducing atmosphere to enhance stability if the film is to be cured ex-situ. The densification generally takes place in a reducing environment while heating the substrate. The densification treatment is particularly suitable for silicon-oxygen-carbon low dielectric constant films that have been deposited at low temperature.

Claims

1. A method of depositing a carbon-doped silicon oxide layer upon a substrate, the method comprising:

providing the substrate to a deposition chamber;

flowing a process gas comprising an organosilicon precursor having at least one silicon-carbon bond and an oxygen source into the deposition chamber during a first deposition step while maintaining the deposition chamber at a chamber pressure level and other process conditions suitable for depositing carbon-doped silicon oxide material over the substrate using a thermal chemical vapor deposition process; and

during a second deposition step subsequent to the first deposition step, flowing a process gas comprising an organosilicon precursor having at least one silicon-carbon bond and an oxygen source into the deposition chamber while maintaining the deposition chamber at process conditions suitable for depositing carbon-doped silicon oxide material over the substrate, wherein the process conditions of the deposition chamber during the second deposition step include a chamber pressure level at least 50 Torr less than the chamber pressure level of the first deposition step;

wherein the chamber pressure level during the first deposition step is maintained within a range of between about 200 to 700 Torr, the chamber pressure level during the second deposition step is maintained within a range of between about 50 to 150 Torr and a temperature of the substrate is increased by at least about 25°

Celsius from the first deposition step to the second deposition step.

2. The method set forth in claim 1 wherein the oxygen source in the first deposition step comprises ozone.

3. The method set forth in claim 2 wherein the oxygen source in both the first and second deposition steps comprises ozone and wherein at the end of the carbon-doped silicon oxide deposition process the flow of the organosilicon precursor is shut-off after shutting off the flow of ozone.

4. The method set forth in claim 1 wherein the process gas in both the first and second deposition steps comprises trimethylsilane, ozone, oxygen and an inert gas.

5. The method set forth in claim 1 wherein the process gas in both the first and second deposition steps comprises tetramethylsilane, ozone, oxygen and an inert gas.

6. The method set forth in claim 1 wherein the deposited carbon-doped silicon oxide film has a density of less than or equal to about 1.2 g/cm³.

7. The method set forth in claim 1 wherein the first deposition step is optimized for gapfill while the second deposition step is optimized for deposition rate.

8. The method set forth in claim 1 wherein, prior to initiating a flow of the process gas in the first deposition step, a flow of an inert gas and oxygen is introduced into the deposition chamber, then after the chamber pressure level of the first deposition step is reached, a flow of ozone is substituted for the flow of oxygen.

9. The method set forth in claim 1 wherein the process gas in both the first and second deposition steps further comprises one or more dopant sources selected from boron and phosphorus sources.