Surface treatment and deposition for reduced outgassing

• US 9,404,178 B2
• Filed: 06/12/2012
• Issued: 08/02/2016
• Est. Priority Date: 07/15/2011
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Liang, Jingmei, Chen, Xiaolin, Ingle, Nitin K., Venkataraman, Shankar
• Primary Examiner(s): Padgett, Marianne L
• Application Number:
  US13/494,341
• Publication Number:
  US 20130149462A1
• Time in Patent Office: 1,512 Days
• Field of Search: 427/562, 427/563, 427/568, 427/574, 427/579, 438/788, 438/792
• US Class Current: 1/1
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/452 by activating reactive gas streams before their introduction into the reaction chamber, e.g. by ionisation or addition of reactive species
• CPC Class Codes: C23C 16/45514 Mixing in close vicinity to the substrate
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/505 using radio frequency discharges
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• 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 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]

Abstract

A method of forming a dielectric layer is described. The method first deposits a silicon-nitrogen-and-hydrogen-containing (polysilazane) layer by radical-component chemical vapor deposition (CVD). The silicon-nitrogen-and-hydrogen-containing layer is formed by combining a radical precursor (excited in a remote plasma) with an unexcited carbon-free silicon precursor. A silicon oxide capping layer may be formed from a portion of the carbon-free silicon-nitrogen-and-hydrogen-containing layer to avoid time-evolution of underlying layer properties prior to conversion into silicon oxide. Alternatively, the silicon oxide capping layer is formed over the silicon-nitrogen-and-hydrogen-containing layer. Either method of formation involves the formation of a local plasma within the substrate processing region.

Claims

1. A method of forming a dielectric layer on a substrate, the method comprising the sequential steps of:

forming a carbon-free silicon-nitrogen-and-hydrogen-containing layer on the substrate in a first substrate processing region containing the substrate by;

flowing an unexcited precursor into a remote plasma region to produce a radical-precursor,

combining a carbon-free silicon-containing precursor with the radical-precursor in the first substrate processing region, wherein the first substrate processing region is devoid of plasma during the forming the carbon-free silicon-nitrogen-and-hydrogen-containing layer, and

depositing a carbon-free silicon-nitrogen-and-hydrogen-containing layer over the substrate, wherein the carbon-free silicon-nitrogen-and-hydrogen-containing layer is flowable during deposition and flows into a trench on a deposition surface of the substrate as the carbon-free silicon-nitrogen-and hydrogen-containing layer deposits; and

forming a silicon oxide capping layer on the carbon-free silicon-nitrogen-and-hydrogen-containing layer by;

flowing an oxygen-containing precursor into a second substrate processing region containing the substrate,

flowing a silicon-containing precursor into the second substrate processing region,

forming a plasma from the oxygen-containing precursor and the silicon-containing precursor in the second substrate processing region, and

depositing the silicon oxide capping layer over the carbon-free silicon-nitrogen-and-hydrogen-containing layer

wherein the dielectric layer comprises the carbon-free silicon-nitrogen-and-hydrogen-containing layer and the silicon oxide capping layer; and

converting the underlying carbon-free silicon-nitrogen-and-hydrogen-containing layer to silicon oxide despite an intervening presence of the silicon oxide capping layer.

2. The method of claim 1 wherein a temperature of the substrate is greater than or about 25°

C. and less than or about 125°

C. during formation of the carbon-free silicon-nitrogen-and-hydrogen-containing layer.

3. The method of claim 1 wherein the substrate temperature is less than or about 200°

C. during formation of the silicon oxide capping layer.

4. The method of claim 1 wherein a thickness of the silicon oxide capping layer is about 10 nm or more.

5. The method of claim 1 wherein the unexcited precursor comprises nitrogen and the radical precursor is a radical-nitrogen precursor.

6. The method of claim 1 wherein the unexcited precursor comprises at least one of N₂H₂, NH₃, N₂ and H₂ and the carbon-free silicon-containing precursor comprises one of H₂N(SiH₃), HN(SiH₃)₂ or N(SiH₃)₃.

7. The method of claim 1 wherein the first substrate processing region is the second substrate processing region.

8. The method of claim 1 wherein forming a plasma from the oxygen-containing precursor and the silicon-containing precursor in the second substrate processing region comprises applying a plasma power of below or about 1000 W.

9. The method of claim 1 wherein a thickness of the silicon oxide capping layer is greater than or about 50 nm.