Thermal CVD process for depositing a low dielectric constant carbon-doped silicon oxide film

• US 6,602,806 B1
• Filed: 08/07/2000
• Issued: 08/05/2003
• Est. Priority Date: 08/17/1999
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Yieh, Ellie, Xia, Li-Qun, Gaillard, Frederic, Lim, Tian H., Geiger, Fabrice
• Primary Examiner(s): Elms, Richard
• Assistant Examiner(s): SMITH, BRADLEY
• Application Number:
  US09/632,668
• Time in Patent Office: 1,093 Days
• Field of Search: 438/786, 438/778, 438/789, 438/790, 438/783
• US Class Current: 438/786
• CPC Class Codes: C23C 16/401 containing silicon
• 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 21/02129 the material being boron or phosphorus doped silicon oxides, e.g. BPSG, BSG or PSG
• 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 21/02312 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 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC

Abstract

A method for providing a dielectric film having a low dielectric constant. The deposited film is particularly useful as an intermetal or premetal dielectric layer in an integrated circuit. The low dielectric constant film is a carbon-doped silicon oxide layer deposited from a thermal, as opposed to plasma, CVD process. The layer is deposited from a process gas of ozone and an organosilane precursor having at least one silicon-carbon (Si—C) bond. During the deposition process the wafer is heated to a temperature less than 250° C. and preferably to a temperature between 100-200° C. Enhancements to the process include adding Boron and/or Phosphorus dopants, two step deposition, and capping the post cured layer.

Claims

1. A method for forming an insulation layer over a substrate disposed in a substrate processing chamber, the method comprising:

flowing a process gas comprising ozone and an organosilane precursor having at least one silicon-carbon bond into the substrate processing chamber at a pressure of 50-450 Torr;

heating the substrate to a temperature between 100-250°

C. to form a carbon-doped silicon oxide layer over the substrate using a thermal chemical vapor deposition technique; and

curing the carbon-doped silicon oxide layer after it is formed over the substrate by heating the substrate to a temperature between 300 and 500°

C. for a least 15 minutes in an ex situ process, wherein said curing is done in a conventional furnace at atmospheric pressure.

2. A method for forming an insulation layer over a substrate disposed in a substrate processing chamber, the method comprising:

flowing a process gas comprising ozone and an organosilane precursor having at least one silicon-carbon bond into the substrate processing chamber at a pressure of 50-450 Torr;

heating the substrate to a temperature between 100-250°

C. to form a carbon-doped silicon oxide layer over the substrate using a thermal chemical vapor deposition technique; and

curing the carbon-doped silicon oxide layer after it is formed over the substrate by heating the substrate to a temperature between 300 and 500°

C. for at least 15 minutes in an ex situ process, wherein said curing heats the substrate in a vacuum enivronment.

3. A method for depositing an intermetal dielectric film over a plurality of conductive lines, the method comprising:

flowing a process gas comprising ozone and an organosilane precursor having at least one silicon-carbon bond into the substrate processing chamber wherein a pressure level within the substrate processing chamber is set to between about 50 and 450 Torr;

heating the substrate to a temperature of between about 100-250°

C. to form a carbon-doped silicon oxide layer over a plurality of conductive lines using a thermal chemical vapor deposition technique; and

thereafter, curing the carbon-doped silicon oxide layer by heating the substrate to a temperature between 300 and 500°

C. for at least 15 minutes in an ex situ process, wherein said curing heats the substrate in a vacuum environment.

4. A method for depositing an intermetal dielectric film over a plurality of conductive lines, the method comprising:

flowing a process gas comprising ozone and an organosilane precursor having at least one silicon-carbon bond into the substrate processing chamber wherein a pressure level within the substrate processing chamber is set to between about 50 and 450 Torr;

heating the substrate to a temperature of between about 100-250°

C. to form a carbon-doped silicon oxide layer over a plurality of conductive lines using a thermal chemical vapor deposition technique; and

thereafter, curing the carbon-doped silicon oxide layer by heating the substrate to a temperature between 300 and 500°

C. for at least 15 minutes in an ex situ process, wherein said curing heats the substrate in a vacuum environment.

5. A method for depositing an intermetal dielectric film over a plurality of conductive lines, the method comprising:

flowing a process gas comprising ozone and an organosilane precursor having at least one silicon-carbon bond into the substrate processing chamber wherein a pressure level within the substrate processing chamber is set to between about 50 and 450 Torr;

heating the substrate to a temperature of between about 100-250°

C. to form a carbon-doped silicon oxide layer over the plurality of conductive lines using a thermal chemical vapor deposition technique; and

thereafter, curing the carbon-doped silicon oxide layer, wherein flow of ozone gas is stopped at least 2-3 seconds before the organosilane precursor flow wherein deposition of said carbon-doped silicon oxide film is substantially complete.

6. A method for forming an insulation layer over a substrate disposed in a substrate processing chamber, the method comprising:

flowing a process gas comprising ozone, one or more dopants, and an organosilane precursor having at least one silicon-carbon bond into the substrate processing chamber at a pressure of 50-450 Torr; and

heating the substrate to a temperature between 100-250°

C. to form a carbon-doped silicon oxide layer over the substrate using a thermal chemical vapor deposition technique, wherein said one or more dopants include boron (B) or phosphorus (P) or both.

7. The method of claim 6 wherein said one or more dopants is phosphorous.

8. A method for forming an insulation layer over a substrate disposed in a substrate processing chamber, the method comprising:

flowing a process gas comprising ozone and an organosilane precursor having at least one silicon-carbon bond into the substrate processing chamber at a pressure of 50-450 Torr; and

heating the substrate to a temperature between 100-250°

C. to form a carbon-doped silicon oxide layer over the substrate using a thermal chemical vapor deposition technique, wherein a second carbon-doped silicon oxide layer is formed over the carbon-doped silicon oxide layer (first layer), and wherein said first layer is deposited using a deposition process optimized for gap fill in and said second layer is deposited using a deposition process optimized for deposition rate.

9. The method of claim 8 wherein said first layer is seposited using a thermal CVD process at a pressure greater than about 200 Torr and a temperature less than about 125°

C.

10. The method of claim 8 wherein said second layer is deposited using a thermal CVD process at a pressure less than about 150 Torr and a temperature between about 150-250°

C.

11. The method of claim 8 wherein said second layer is deposited using a plasma enhanced chemical vapor deposition (PECVD) process.