Smooth Silicon-Containing Films

• US 20110236600A1
• Filed: 12/16/2010
• Published: 09/29/2011
• Est. Priority Date: 03/25/2010
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Sriram, Mandyam, van Schravendijk, Bart, Antonelli, George Andrew, O'Loughlin, Jennifer, Fox, Keith, Womack, Joe, Niu, Dong
• Granted Patent: US 8,709,551 B2
• Time in Patent Office: Days
• US Class Current: 427/579
• CPC Class Codes: C23C 16/24 Deposition of silicon only
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: C23C 16/4401 Means for minimising impurities, e.g. dust, moisture or residual gas, in the reaction chamber
• CPC Class Codes: C23C 16/45523 Pulsed gas flow or change of composition over time
• CPC Class Codes: C23C 16/505 using radio frequency discharges
• CPC Class Codes: C23C 16/509 using internal electrodes
• CPC Class Codes: C23C 16/54 Apparatus specially adapted for continuous coating
• CPC Class Codes: H01L 21/02104 Forming layers deposition in general C23C; crystal growth in general C30B
• CPC Class Codes: H01L 21/02123 the material containing silicon
• 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 21/0214 the material being a silicon oxynitride, e.g. SiON or SiON:H
• 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 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02263 deposition from the gas or vapour phase
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0245 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02507 Alternating layers, e.g. superlattice
• CPC Class Codes: H01L 21/02532 : Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0254 : Nitrides
• CPC Class Codes: H01L 21/6719 : characterized by the construction of the processing chambers, e.g. modular processing chambers
• CPC Class Codes: H01L 21/67201 : characterized by the construction of the load-lock chamber
• CPC Class Codes: H01L 21/67207 : comprising a chamber adapted to a particular process
• CPC Class Codes: H10B 99/00 : Subject matter not provided for in other groups of this subclass

Abstract

Methods and hardware for depositing ultra-smooth silicon-containing films and film stacks are described. In one example, an embodiment of a method for forming a silicon-containing film on a substrate in a plasma-enhanced chemical vapor deposition apparatus is disclosed, the method including supplying a silicon-containing reactant to the plasma-enhanced chemical vapor deposition apparatus; supplying a co-reactant to the plasma-enhanced chemical vapor deposition apparatus; supplying a capacitively-coupled plasma to a process station of the plasma-enhanced chemical vapor deposition apparatus, the plasma including silicon radicals generated from the silicon-containing reactant and co-reactant radicals generated from the co-reactant; and depositing the silicon-containing film on the substrate, the silicon-containing film having a refractive index of between 1.4 and 2.1, the silicon-containing film further having an absolute roughness of less than or equal to 4.5 Å as measured on a silicon substrate.

Claims

1. A method for forming a silicon-containing film on a substrate in a plasma-enhanced chemical vapor deposition apparatus, the method comprising:

supplying a silicon-containing reactant to the plasma-enhanced chemical vapor deposition apparatus;

supplying a co-reactant to the plasma-enhanced chemical vapor deposition apparatus;

supplying a capacitively-coupled plasma to a process station of the plasma-enhanced chemical vapor deposition apparatus, the plasma including silicon radicals generated from the silicon-containing reactant and co-reactant radicals generated from the co-reactant; and

depositing the silicon-containing film on the substrate, the silicon-containing film having a refractive index of between 1.4 and 2.1, the silicon-containing film further having an absolute roughness of less than 4.5 Å

as measured on a silicon substrate.

2. The method of claim 1, wherein the silicon-containing film is a silicon dioxide film and wherein the silicon dioxide film has an absolute roughness of less than 4.5 Å

as measured on a silicon substrate over a thickness range of up to 3000 Å

of the silicon dioxide film.

3. The method of claim 1, wherein the co-reactant includes one or more of NH₃, N₂O, CO, and CO₂.

4. The method of claim 1, wherein the silicon-containing reactant includes one or more of silane, disilane, a halogen-substituted silane, and an alkyl-substituted silane.

5. The method of claim 1, wherein the plasma has an ion density of less than 2×

10¹⁰ ions/cm³.

6. The method of claim 1, further comprising controlling an absolute roughness of the silicon-containing film by supplying a process gas mixture including the co-reactant in an amount at least 150 times an amount of the silicon-containing reactant.

7. The method of claim 1, wherein supplying a plasma to the substrate includes generating a high frequency plasma.

8. A method for forming a film stack including a first film and a second film on a substrate in-situ, the first film having a different material composition from the second film, the method comprising:

in a first film deposition phase,

supplying a first reactant gas mixture to a process station,

maintaining a first plasma using the first reactant gas mixture,

with the first plasma, depositing the first film on the substrate; and

in a second film deposition phase, and without an intervening vacuum break,

supplying a second reactant gas mixture to the process station,

maintaining a second plasma using the second reactant gas mixture,

with the second plasma, depositing the second film on the substrate, and,

controlling a process parameter of the second film deposition phase so that the absolute roughness of the second film decreases with increasing thickness of the second film.

9. The method of claim 8, wherein the first film is one of a polycrystalline silicon film and an amorphous silicon film and wherein the second film is a silicon-containing film having a refractive index of between 1.4 and 2.1, the silicon-containing film further having an absolute roughness of less than 4.5 Å

as measured on a silicon substrate.

10. The method of claim 9, wherein the first film includes one of a boron dopant, an arsenic dopant, and a phosphorous dopant.

11. The method of claim 8, wherein the first film is a silicon nitride film and wherein the second film is a silicon-containing film having a refractive index of between 1.4 and 2.1, the silicon-containing film further having an absolute roughness of less than 4.5 Å

as measured on a silicon substrate.

12. The method of claim 8, wherein increasing a thickness of the second film decreases an absolute roughness of a third film relative to an absolute roughness of the first film, the third film being deposited in a third film deposition phase in-situ with the first film deposition phase and the second film deposition phase.

13. The method of claim 8, wherein controlling the process parameter of the second film deposition phase includes supplying an amount of a silicon-containing reactant in the second reactant gas mixture at a ratio equal to or less than 1:

150 of a total amount of the second reactant gas mixture.

14. The method of claim 8, wherein controlling the process parameter of the second film deposition phase includes generating the second plasma with a capacitively-coupled plasma source.

15. The method of claim 9, wherein controlling the process parameter of the second film deposition phase includes generating the second plasma at a process station pressure of 8 torr or less.

16. The method of claim 9, wherein controlling the process parameter of the second film deposition phase includes maintaining an ion density of less than 2×

10¹⁰ ions/cm³ in the second plasma.

17. The method of claim 9, controlling the process parameter of the second film deposition phase includes supplying an inert gas to the second plasma.

18. The method of claim 9, further comprising:

applying photoresist to the substrate;

exposing the photoresist to light;

patterning the resist with a pattern and transferring the pattern to the substrate; and

selectively removing the photoresist from the substrate.

19. A plasma-enhanced chemical vapor deposition apparatus configured to deposit a silicon-containing film on a substrate, the apparatus comprising:

a process station;

a first reactant feed for supplying a silicon-containing reactant to the process station;

a second reactant feed for supplying a co-reactant to the process station;

a capacitively-coupled plasma source; and

a controller configured to control the capacitively-coupled plasma source to maintain a plasma and to control one or more process parameters of the process station to effect the deposition of a silicon-containing film having a refractive index of between 1.4 and 2.1 and an absolute roughness of less than 4.5 Å

as measured on a silicon substrate.

20. A system, comprising the apparatus of claim 19 and a stepper tool.

21. The apparatus of claim 19, further comprising a showerhead disposed within the process station, the showerhead configured to distribute process gases to the substrate, the showerhead fluidly coupled to one or more of an NH₃ source, an N₂O source, a CO source, a CO₂ source, a silane source, a disilane source, a nitrogen source, a hydrazine source, a halogen-substituted silane source, and an alkyl-substituted silane source.