Capping layer for reduced outgassing

• US 8,466,073 B2
• Filed: 04/17/2012
• Issued: 06/18/2013
• Est. Priority Date: 06/03/2011
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Wang, Linlin, Mallick, Abhijit Basu, Ingle, Nitin K.
• Primary Examiner(s): Dang, Trung Q
• Application Number:
  US13/448,624
• Publication Number:
  US 20120309205A1
• Time in Patent Office: 427 Days
• Field of Search: 438/787, 257/E21.278
• US Class Current: 438/787
• CPC Class Codes: C23C 16/30 Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• 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 16/56 After-treatment
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• 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 21/02219 the compound comprising silicon and nitrogen
• CPC Class Codes: H01L 21/02323 introduction of oxygen
• CPC Class Codes: H01L 21/02326 into a nitride layer, e.g. changing SiN to SiON

Abstract

A method of forming a silicon oxide layer is described. The method first deposits a silicon-nitrogen-and-hydrogen-containing (polysilazane) film by radical-component chemical vapor deposition (CVD). The silicon-nitrogen-and-hydrogen-containing film is formed by combining a radical precursor (excited in a remote plasma) with an unexcited carbon-free silicon precursor. A capping layer is formed over the silicon-nitrogen-and-hydrogen-containing film to avoid time-evolution of underlying film properties prior to conversion into silicon oxide. The capping layer is formed by combining a radical oxygen precursor (excited in a remote plasma) with an unexcited silicon-and-carbon-containing-precursor. The films are converted to silicon oxide by exposure to oxygen-containing environments. The two films may be deposited within the same substrate processing chamber and may be deposited without breaking vacuum.

Claims

1. A method of forming a silicon oxide layer on a substrate, the method comprising:

forming a first layer comprising silicon, nitrogen and hydrogen by;

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

combining a carbon-free silicon-containing precursor with the radical-precursor in a first plasma-free substrate processing region, and

depositing a carbon-free silicon-nitrogen-and-hydrogen-containing layer over the substrate; and

forming a second layer comprising silicon and oxygen by;

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

combining a silicon-and-carbon-containing precursor with the radical-oxygen precursor in a second plasma-free substrate processing region, and

depositing a silicon-oxygen-and-carbon-containing capping layer over the carbon-free silicon-nitrogen-and-hydrogen-containing layer.

2. The method of claim 1 wherein the substrate is not exposed to air between forming the first layer and forming the second layer.

3. The method of claim 1 wherein unreacted precursors and reaction by-products are removed from the first plasma-free substrate processing region after forming the first layer and before forming the second layer.

4. The method of claim 1 wherein the first remote plasma region is the same as the second remote plasma region and the first plasma-free substrate processing region is the same as the second plasma-free substrate processing region.

5. The method of claim 1 wherein a temperature of the substrate is greater than or about 0°

C. and less than or about 225°

C. during forming of the first layer and the second layer.

6. The method of claim 1 wherein no curing operation is required after forming the second layer to prevent evolution of film properties over time upon exposing the substrate to air.

7. The method of claim 1 wherein the silicon-and-carbon-containing precursor comprises one of dimethylsilane, trimethylsilane, tetramethylsilane, diethylsilane, tetramethylorthosilicate, tetramethyldisiloxane, tetraethylorthosilicate, octamethyltrisiloxane, octamethylcyclotetrasiloxane, tetramethyldimethyldimethoxydisilane, tetramethylcyclotetrasiloxane, dimethyldimethoxysilane, diethylmethylsilane, methyltriethoxysilane, phenyldimethylsilane, and phenylsilane.

8. The method of claim 1 further comprising curing the first and second layers in an ozone-containing atmosphere to convert the first and second layers to a silicon-and-oxygen-containing layer.

9. The method of claim 8 wherein a temperature of the substrate is greater than or about 75°

C. and less than or about 225°

C. during the curing operation.

10. The method of claim 8 further comprising exposing me silicon-and-oxygen-containing layer to a humid environment having at least 50% relative humidity to convert the silicon-and-oxygen-containing layer to a silicon oxide layer.

11. The method of claim 10 wherein a temperature of the substrate is greater than or about 25°

C. and less than 100°

C. during the exposing operation.

12. The method of claim 10 wherein the silicon oxide layer consists essentially of silicon and oxygen.

13. The method of claim 1 wherein a thickness of the second layer is between about 100 Å

and about 300 Å

.

14. The method of claim 1 wherein the carbon-free silicon-nitrogen-and-hydrogen-containing layer is flowable during deposition.

15. The method of claim 1 wherein the substrate is patterned and has a trench having a width of about 50 nm or less.

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

17. The method of claim 1 wherein the unexcited precursor comprises at least one of N₂H₂, NH₃, N₂ and H₂.

18. The method of claim 1 wherein the carbon-free silicon-containing precursor comprises one of N(SiH₃)H₂, N(SiH₃)₂H or N(SiH₃)₃.

19. The method of claim 1 further comprising removing process effluents from the first plasma-free substrate processing region between the operations of forming the first and second layers.