Advanced low dielectric constant organosilicon plasma chemical vapor deposition films

• US 7,494,938 B2
• Filed: 02/05/2007
• Issued: 02/24/2009
• Est. Priority Date: 02/16/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation, Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: International Business Machines Corporation, Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Nogami, Takeshi, Lee, Jia, Restaino, Darryl D., Nguyen, Son V., Lane, Sarah L., Ida, Kensaku
• Primary Examiner(s): LINDSAY JR, WALTER LEE
• Application Number:
  US11/671,022
• Publication Number:
  US 20070128882A1
• Time in Patent Office: 750 Days
• Field of Search: 438/623, 438/29, 438/734, 438/648, 438/637, 438/780, 438/781, 438/789, 438/788
• US Class Current: 438/780
• 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 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/02351 treatment by exposure to corpuscular radiation, e.g. exposure to electrons, alpha-particles, protons or ions
• CPC Class Codes: H01L 21/02354 using a coherent radiation, e.g. a laser
• CPC Class Codes: H01L 21/3122 layers comprising polysiloxane compounds
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/7682 the dielectric comprising air gaps
• CPC Class Codes: H01L 2221/1047 the air gaps being formed by pores in the dielectric

Abstract

A porous low k or ultra low k dielectric film comprising atoms of Si, C, O and H (hereinafter “SiCOH”) in a covalently bonded tri-dimensional network structure having a dielectric constant of less than about 3.0, a higher degree of crystalline bonding interactions, more carbon as methyl termination groups and fewer methylene, —CH₂— crosslinking groups than prior art SiCOH dielectrics is provided. The SiCOH dielectric is characterized as having a FTIR spectrum comprising a peak area for CH₃+CH₂ stretching of less than about 1.40, a peak area for SiH stretching of less than about 0.20, a peak area for SiCH₃ bonding of greater than about 2.0, and a peak area for Si—O—Si bonding of greater than about 60%, and a porosity of greater than about 20%.

Claims

1. A method for forming a SiCOH dielectric on a substrate comprising:

placing a substrate in a reactor;

introducing a first precursor comprising atoms of Si, C, O and H, an oxidizing agent and an inert carrier into said reactor; and

depositing a SiCOH dielectric film comprising atoms of Si, C, O and H and having a tri-dimensional network structure in which the material has a FTIR spectrum comprising a peak area for CH₃+CH₂ stretching of less than about 1.40, a peak area for SiH stretching of less than about 0.20, a peak area for SiCH₃ bonding of greater than about 2.0, and a peak area for Si—

O—

Si bonding of greater than about 60%, and a porosity of greater than about 20% onto said substrate.

2. The method of claim 1 wherein said first precursor comprises organic molecules with a ring structure that includes at least atoms of Si, C, O and H.

3. The method of claim 2 wherein said first precursor comprises one of 1,3,5,7-tetramethylcyclotetrasiloxane (“

TMCTS”

or “

C₄H₁₆O₄Si₄”

), octamethylcyclotetrasiloxane (OMCTS), diethoxymethylsilane (DEMS), dimethyldimethoxysilane (DMDMOS), diethylmethoxysilane (DEDMOS), or other cyclic and non-cyclic silanes or siloxanes.

4. The method of claim 1 wherein said oxidizing agent comprises at least one of O₂, CO₂ or N₂O.

5. The method of claim 1 wherein said inert carrier comprises Ar, He, Ne, Xe or mixtures thereof.

6. The method of claim 1 wherein said first precursor is OMCTS, said oxidizing agent is O₂ and said inert carrier is He.

7. The method of claim 1 wherein said depositing is performed using a low high frequency (HF)/low frequency (LF) power on the order of about 150 Watts or less.

8. The method of claim 1 wherein said depositing is performed using an oxidizing agent/first precursor molar ratio of about 1:

2 or greater.

9. The method of claim 1 wherein said depositing includes setting a substrate temperature at between about 250°

C. and about 450°

C.;

setting a high frequency RF power density at between about 0.20 W/cm² and about 0.85 W/cm²;

setting the first precursor flow rate at between about 1800 mg/min and about 3600 mg/min, setting the oxidizing agent flow rate at between about 120 to about 320 sccm, setting the inert carrier gases flow rate at between about 500 sccm to about 2000 sccm;

setting a reactor pressure at a pressure between about 4 Torr and about 8 Torr;

setting a high frequency RF power between about 150 W and about 800 W; and

setting a low frequency power between about 0 W and about 200 W.

10. The method of claim 1 further comprising subjecting said deposited dielectric material is a post treatment step.

11. The method of claim 10 wherein said post treatment step comprises utilizing an energy source selected from thermal, electron beam, plasma, microwave and UV optical radiation.