Decreasing the etch rate of silicon nitride by carbon addition

• US 7,501,355 B2
• Filed: 06/29/2006
• Issued: 03/10/2009
• Est. Priority Date: 06/29/2006
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Xia, Li-Qun, M'Saad, Hichem, Peterson, Chad, Bhatia, Ritwik
• Primary Examiner(s): Coleman; W. David
• Assistant Examiner(s): WHITE, SHAKA SHAKAR
• Application Number:
  US11/478,273
• Publication Number:
  US 20080014761A1
• Time in Patent Office: 985 Days
• Field of Search: 438/791, 438/795, 438/790, 438/792, 438/778, 438/687, 438/709, 438/637
• US Class Current: 438/791
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/0332 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 21/76825 by exposing the layer to particle radiation, e.g. ion implantation, irradiation with UV light or electrons etc. plasma treatment H01L21/76826
• CPC Class Codes: H01L 21/76829 characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers

Abstract

Methods for forming silicon nitride hard masks are provided. The silicon nitride hard masks include carbon-doped silicon nitride layers and undoped silicon nitride layers. Carbon-doped silicon nitride layers that are deposited from a mixture comprising a carbon source compound, a silicon source compound, and a nitrogen source in the presence of RF power are provided. Also provided are methods of UV post-treating silicon nitride layers to provide silicon nitride hard masks. The carbon-doped silicon nitride layers and UV post-treated silicon nitride layers have desirable wet etch rates and dry etch rates for hard mask layers.

Claims

1. A method of forming a silicon nitride hard mask, comprising:

introducing a silicon source compound into the chamber;

introducing a nitrogen source into the chamber;

reacting the silicon source compound and nitrogen source in the presence of RF power to deposit a silicon nitride layer on a substrate in the chamber; and

reducing a wet etch rate of the silicon nitride layer by UV post-treating the silicon nitride layer to form the silicon nitride hard mask.

2. The method of claim 1, wherein the silicon source compound is silane, trimethylsilane, or TEOS and the nitrogen source is NH₃.

3. The method of claim 1, wherein the substrate is maintained at a temperature between about 480°

C. and about 600°

C.

4. The method of claim 1, wherein silicon nitride layer is UV post-treated for between about 1 minute and about 60 minutes.

5. The method of claim 1, further comprising introducing an organosilicon compound into a chamber and reacting the organosilicon compound with the silicon source compound and nitrogen source.

6. The method of claim 1, further comprising patterning the silicon nitride hard mask and transferring the pattern in the silicon nitride hard mask through a layer of the substrate.