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US-12628581-B2 - Substrate processing method

US12628581B2US 12628581 B2US12628581 B2US 12628581B2US-12628581-B2

Abstract

A substrate processing method comprising a gap-fill process is disclosed. The method includes providing a substrate in which a gap is formed in a surface thereof to a reaction space, supplying an oligomeric silicon precursor and a nitrogen-containing gas to the reaction space, forming a silicon nitride film having flowability on the substrate to fill at least a portion of the gap of the substrate while maintaining the reaction space in a plasma state, and densifying the silicon nitride film.

Inventors

  • SangHeon Yong
  • HongSuk Kim
  • JuHyuk Park
  • Kihun KIM
  • Sungha CHOI

Assignees

  • ASM IP HOLDING B.V.

Dates

Publication Date
20260512
Application Date
20230410

Claims (20)

  1. 1 . A method of processing a substrate, the method comprising: providing the substrate in which a gap is formed in a surface thereof to a reaction space; supplying an oligomeric silicon precursor and a nitrogen-containing gas to the reaction space; forming a silicon nitride film having flowability on the substrate to fill at least a portion of the gap of the substrate while maintaining the reaction space in a plasma state; and densifying the silicon nitride film, wherein a pressure within the reaction space is in the range of about 0.5 Torr to about 10 Torr, and wherein the silicon precursor comprises a trisilylamine (TSA) having 2 to 10 repeating units.
  2. 2 . The method of processing a substrate of claim 1 , wherein the oligomeric silicon precursor comprises one or more of dimer-TSA, trimer-TSA, tetramer-TSA, pentamer-TSA, hexamer-TSA, heptamer-TSA, octamer-TSA.
  3. 3 . The method of processing a substrate of claim 1 , wherein the nitrogen-containing gas comprises at least one selected from N 2 , N 2 O, NO 2 , NH 3 , N 2 H 2 , N 2 H 4 , at least one of radicals thereof, and mixtures thereof.
  4. 4 . The method of processing a substrate of claim 1 , wherein the oligomeric silicon precursor comprises trimer-trisilylamine (TSA) and the nitrogen-containing gas comprises NH 3 .
  5. 5 . The method of processing a substrate of claim 1 , wherein, in the step of forming the silicon nitride film, a temperature of the substrate is maintained between about 0° C. and about 100° C.
  6. 6 . The method of processing a substrate of claim 5 , wherein, in the step of forming the silicon nitride film, the temperature of the substrate is maintained between about 30° C. and about 70° C.
  7. 7 . The method of processing a substrate of claim 1 , wherein, in the step of supplying the oligomeric silicon precursor and the nitrogen-containing gas, the oligomeric silicon precursor and the nitrogen-containing gas are supplied so that the ratio of the Si atoms to N atoms in the silicon nitride film is 1:1 or more.
  8. 8 . The method of processing a substrate of claim 1 , wherein, in the step of forming the silicon nitride film, while supplying the oligomeric silicon precursor and the nitrogen-containing gas to the reaction space, RF power is applied to the reaction space to directly generate plasma over the substrate by an in-situ plasma treatment method.
  9. 9 . The method of processing a substrate of claim 1 , wherein the step of densifying the silicon nitride film is performed using any one selected from plasma treatment, UV treatment, or a rapid thermal process, for the silicon nitride film.
  10. 10 . The method of processing a substrate of claim 9 , wherein the step of densifying the silicon nitride film is performed using plasma treatment, and the plasma treatment is performed by an in-situ plasma treatment method in which plasma is directly generated over the substrate while supplying He or Ar gas.
  11. 11 . The method of processing a substrate of claim 10 , wherein the steps of forming the silicon nitride film and densifying the silicon nitride film are performed at the same process temperature, and in the step of densifying the silicon nitride film, second RF power that is greater than first RF power applied to the reaction space in the step of forming the silicon nitride film is applied to the reaction space.
  12. 12 . The method of processing a substrate of claim 11 , wherein the first RF power is in a range of about 100 W to about 500 W, and the second RF power is in the range of about 300 W to about 1,500 W.
  13. 13 . The method of processing a substrate of claim 10 , wherein the steps of forming the silicon nitride film and densifying the silicon nitride film are performed under RF power of the same intensity, and the step of densifying the silicon nitride film is performed at a second process temperature that is greater than a first process temperature in the step of forming the silicon nitride film.
  14. 14 . The method of processing a substrate of claim 1 , wherein the steps of forming the silicon nitride film and densifying the silicon nitride film are repeatedly performed a plurality of times, respectively.
  15. 15 . The method of processing a substrate of claim 1 , wherein the steps of forming the silicon nitride film and densifying the silicon nitride film constitute one super-cycle, and the super-cycle is performed a plurality of times according to the degree of filling of the silicon nitride film within the gap.
  16. 16 . A method of processing a substrate, the method comprising: providing the substrate to a reaction space; supplying an oligomeric silicon precursor having 2 to about 10 chain structures comprising trisilylamine and a nitrogen-containing gas to the reaction space; and forming a silicon nitride film having flowability on the substrate while maintaining the reaction space in a plasma state, wherein a pressure within the reaction space is in the range of about 0.5 Torr to about 10 Torr.
  17. 17 . The method of processing a substrate of claim 16 , further comprising densifying the silicon nitride film after the step of forming the silicon nitride film.
  18. 18 . The method of processing a substrate of claim 16 , wherein the nitrogen-containing gas comprises at least one selected from N 2 , N 2 O, NO 2 , NH 3 , N 2 H 2 , N 2 H 4 , at least one of radicals thereof, and mixtures thereof.
  19. 19 . The method of processing a substrate of claim 16 , wherein, in the step of forming the silicon nitride film, the temperature of the substrate is maintained between about 30° C. and about 70° C.
  20. 20 . The method of processing a substrate of claim 16 , wherein, in the step of supplying the oligomeric silicon precursor and the nitrogen-containing gas, two or more kinds of oligomeric silicon precursor are supplied together to the reaction space.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application Ser. No. 63/330,653 filed Apr. 13, 2022 titled SUBSTRATE PROCESSING METHOD, the disclosure of which is hereby incorporated by reference in its entirety. BACKGROUND 1. Field The present disclosure relates to a method of processing a substrate, and more particularly, to a method of filling the inside of a gap formed on a surface of the substrate with a material having flowability. 2. Description of the Related Art A gap-fill process is widely used in a semiconductor manufacturing process and referred to as a filling process for filling a gap in a gap structure, such as a shallow trench isolation (STI), with an insulating material or a conductive material. On the other hand, as the degree of integration of semiconductor devices increases, the aspect ratio (NR) of the gap in the gap structure is also increasing, and accordingly, due to limitations of a conventional deposition process, it is also getting more and more difficult to fill the inside of the gap having a high aspect ratio in void-free. A chemical vapor deposition (CVD) method or a plasma enhanced chemical vapor deposition (PECVD) method is generally used as a deposition technique in the semiconductor manufacturing process, and in such methods, a source gas and a reaction gas are supplied simultaneously into a reaction space to deposit a desired film on a substrate, and therefore, there is an advantage that the film-forming rate is high. However, when the gap-fill process is performed on the substrate with gaps having the high aspect ratio using the CVD method, the film-forming rate in an upper region of the gap, that is, near an inlet region of the gap, is relatively faster than in a lower region of the gap. Accordingly, there is a disadvantage in that the inlet region of the gap is firstly closed. FIGS. 1A and 1B are diagrams conceptually showing a process in which a void is formed in a gap in a conventional gap-fill process. Referring to FIG. 1A, a gap structure in which a gap 11 is formed in a substrate 10 is shown. For example, when the gap-fill process is performed on the substrate 10 having the gap 11 formed in a surface thereof by the CVD method, a gap-fill layer 12 is formed on the exposed surface of the substrate 10 having the gap 11. The gap-fill layer 12 is relatively conformally formed along a bottom surface and a portion of sidewall surfaces of the gap among the exposed surfaces of the gap, but the gap-fill layer 12 is formed to be relatively thicker in the inlet region of the gap 11, that is, in the upper region thereof, than in the lower region of the gap 11. That is, as the gap-fill layer 12 is formed to be thicker, the rate at which a width W1 decreases in the upper region of the gap 11 becomes greater than the rate at which the width W2 decreases in the lower region of the gap 11. Referring to FIG. 1B, as the gap-fill process further proceeds, a thickness of the gap-fill layer 12 in the upper region of the gap 11 becomes thicker, and the width W1 in the upper region of the gap 11 gradually decreases. In the end, when the gap-fill layers 12 meet each other along the periphery of the gap 11 in the upper region of the gap 11, the upper region of the gap 11 is closed while forming a void 14 inside the gap 11. Accordingly, despite the increasing of the aspect ratio of the gap in the semiconductor manufacturing process, there is a need for a technique for filling the gap without the occurrence of the void in the gap. SUMMARY Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure. The present disclosure provides a substrate processing method in which a gap may be filled with a gap-fill layer without the occurrence of a void in the gap in a gap-fill process of a semiconductor manufacturing process. The present disclosure provides a substrate processing method to prevent external impurities from penetrating into a gap-fill layer filled without voids in a gap-fill process. The present disclosure provides a substrate processing method for forming a silicon nitride film having flowability on the substrate. According to an aspect of the present disclosure, there is provided a method of processing a substrate, the method including: providing the substrate in which a gap is formed in a surface thereof in a reaction space, supplying an oligomeric silicon precursor and a nitrogen-containing gas in the reaction space, forming a silicon nitride film having flowability on the substrate to fill at least a portion of the gap of the substrate while maintaining the reaction space in a plasma state, and densifying the silicon nitride film. In some embodiments, the oligomeric silicon precursor may be in a form of an oligomer having 2 to about 10 chain structures. In some embodiments, the nitrogen-c