Creation of porosity in low-k films by photo-disassociation of imbedded nanoparticles

• US 7,510,982 B1
• Filed: 06/06/2005
• Issued: 03/31/2009
• Est. Priority Date: 01/31/2005
• Status: Expired due to Fees

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Gray, Gary William, Draeger, Nerissa S.
• Primary Examiner(s): Ghyka; Alexander G
• Application Number:
  US11/146,456
• Time in Patent Office: 1,394 Days
• Field of Search: 438/618, 438/783, 438/787
• US Class Current: 438/783
• 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 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/02362 formation of intermediate layers, e.g. capping layers or diffusion barriers
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass
• CPC Class Codes: H01L 21/7682 the dielectric comprising air gaps
• 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 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 2221/1047 the air gaps being formed by pores in the dielectric

Abstract

Porous dielectric layers are produced by embedding and removing nanoparticles in composite dielectric layers. The pores may be produced after the barrier material, the metal or other conductive material is deposited to form a metallization layer. In this manner, the conductive material is provided with a relatively smooth continuous surface on which to deposit.

Claims

1. A method of fabricating an integrated circuit comprising:

embedding nanoparticles in a dielectric network on a substrate in a chamber to form a layer of composite dielectric material, wherein the nanoparticles are selected from silicon or carbon allotropes;

patterning the layer of composite dielectric material to define paths for the conductive lines and filling the paths with conductive material;

removing excess conductive material to thereby form an exposed pattern of conductive lines in the composite dielectric material; and

removing at least some of the nanoparticles by UV-initiated photo-dissociation, thereby creating a porous dielectric network.

2. The method of claim 1, wherein substantially all of nanoparticles are approximately the same size, the size being between 0.5 and 50 angstroms.

3. The method of claim 1, wherein embedding nanoparticles comprises embedding nanoparticles of at least two size distributions;

each distribution centered on a size between 0.5 and 50 angstroms.

4. The method of claim 1, further comprising

forming the dielectric network on the substrate by depositing a dielectric matrix on the substrate and curing the matrix.

5. The method of claim 4, wherein the nanoparticles are co-deposited on the substrate with the matrix.

6. The method of claim 4, wherein the nanoparticles are deposited in alternating layers with the dielectric matrix.

7. The method of claim 1, wherein embedding nanoparticles comprises delivering the nanoparticles to the chamber entrained in a vapor.

8. The method of claim 4, further comprising delivering a dielectric matrix precursor gas to the chamber at the same time as the nanoparticles are delivered.

9. The method of claim 4, further comprising delivering a dielectric matrix precursor gas to the chamber in alternating pulses with the nanoparticle delivery stream.

10. The method of claim 1, further comprising generating the nanoparticles in a plasma upstream of the chamber.

11. The method of claim 1, further comprising generating the nanoparticles in a plasma within the chamber.

12. The method of claim 1 wherein the porous dielectric network is a closed-cell structure.

13. The method of claim 1 wherein porous dielectric network is an open-cell structure.