US-12628400-B2 - Seam free titanium nitride gapfill

Abstract

Embodiments of the disclosure relate to methods of depositing seam-free gapfill. In some embodiments, the gapfill consists of titanium nitride. The gapfill methods comprise forming a first layer and a second layer. The firs layer is formed without treatment or densification, while the second layer is formed with periodic treatment. The resulting gapfill in advantageously seam-free.

Inventors

• Radhika P. Patil
• Tatsuya E. Sato
• Haoyan Sha
• Abinash Tripathy
• Michael S. Jackson
• Janardhan DEVRAJAN

Assignees

• APPLIED MATERIALS, INC.

Dates

Publication Date

20260512

Application Date

20230530

Claims (20)

1. 1 . A method of depositing titanium nitride gapfill, the method comprising: exposing a semiconductor substrate surface to a titanium amide precursor to form a first TiN layer, the semiconductor substrate surface comprising a plurality of stacked nanosheets and at least one feature between adjacent nanosheets, the first TiN layer forming around the plurality of nanosheets; and exposing the first TiN layer to a titanium precursor and a nitrogen-containing plasma to form a second TiN layer directly on the first TiN layer, wherein the first TiN layer and the second TiN layer combine to completely fill the at least one feature with a TiN gapfill material which is substantially free of a seam.
2. 2 . The method of claim 1 , wherein the at least one feature has a width in a range of about 4 nm to about 5 nm.
3. 3 . The method of claim 1 , wherein the titanium amide precursor comprises tetrakis(dimethylamido)titanium (TDMAT).
4. 4 . The method of claim 1 , wherein depositing the first TiN layer comprises a thermal decomposition process.
5. 5 . The method of claim 1 , wherein the semiconductor substrate surface is maintained at a temperature in a range of about 250° C. to about 350° C. while forming the first TiN layer.
6. 6 . The method of claim 1 , wherein the semiconductor surface is exposed to the titanium amide precursor at a pressure in a range of about 1 Torr to about 5 Torr.
7. 7 . The method of claim 1 , wherein the first TiN layer is formed by a plurality of dep-purge cycles comprising at least one deposition phase and at least one purge phase.
8. 8 . The method of claim 1 , wherein the second TiN layer is formed by a plurality of dep-treat cycles comprising at least one deposition phase and at least one treatment phase.
9. 9 . The method of claim 8 , wherein the deposition phase comprises exposing the first TiN layer to the titanium precursor to form an untreated TiN layer.
10. 10 . The method of claim 9 , wherein the titanium precursor comprises tetrakis(dimethylamido)titanium (TDMAT).
11. 11 . The method of claim 9 , wherein the treatment phase comprises exposing the untreated TiN layer to the nitrogen-containing plasma to form the second TiN layer.
12. 12 . The method of claim 1 , wherein the nitrogen-containing plasma is formed from nitrogen gas (N2).
13. 13 . The method of claim 1 , wherein the nitrogen-containing plasma is formed away from the semiconductor substrate surface.
14. 14 . The method of claim 1 , wherein the nitrogen-containing plasma has a power in a range of about 2000 W to about 5000 W.
15. 15 . The method of claim 1 , wherein the semiconductor substrate surface is maintained at a temperature in a range of about 250° C. to about 350° C. while forming the second TiN layer.
16. 16 . The method of claim 1 , wherein the first TiN layer has a density in a range of about 3.5 g/cm 3 to about 3.8 g/cm 3 and wherein the TiN gapfill material has a density in a range of about 3.0 g/cm 3 to about 5.0 g/cm 3 .
17. 17 . The method of claim 1 , wherein the first TiN layer is amorphous when deposited.
18. 18 . The method of claim 1 , wherein the TiN gapfill material is majority crystalline.
19. 19 . The method of claim 1 , wherein the method completely fills the at least one feature without an etch process to remove material from the semiconductor substrate surface.
20. 20 . A method of depositing titanium nitride gapfill, the method comprising: depositing a first TiN layer by a thermal decomposition process comprising exposing a semiconductor substrate surface to TDMAT, the semiconductor substrate surface comprising a plurality of stacked nanosheets and at least one feature between adjacent nanosheets, the first TiN layer forming around the plurality of nanosheets and the first TiN layer being amorphous; and exposing the first TiN layer to a plurality of cycles comprising a deposition phase and treatment phase, the deposition phase comprising TDMAT, the treatment phase comprising a nitrogen-containing plasma, to form a second TiN layer directly on the first TiN layer, wherein the first TiN layer and the second TiN layers combine to completely fill the at least one feature with a substantially crystalline TiN gapfill material which is substantially free of a seam.

Description

TECHNICAL FIELD Embodiments of the disclosure generally relate to electronic devices and methods of forming electronic devices. In particular, some embodiments of the disclosure provide seam-free titanium nitride films. BACKGROUND Gapfill of features and structures is an ongoing challenge in the field of semiconductor manufacturing. Many processes affect regions near an opening more than within the feature. Accordingly, the quantity and composition of the deposited film can vary depending on the location within the feature. This variability can lead to premature closing where a feature opening is closed before the feature is filled. To remedy this problem, multi-stage cyclic processes have been developed which both deposit and etch the film. These processes suffer from increased processing times, decreased throughput and potential adverse effects from halogen-based etching processes. In some cases, deposition-only schemes, particularly those which use plasma, can be tuned to deposit and densify a material within a feature without prematurely closing the feature. These materials, however, can suffer from defects (e.g., seams within the deposited material. Therefore, there remains a need for processes to deposit defect free gapfill within features. SUMMARY One or more embodiments of the disclosure are directed to a method of seamless titanium nitride gapfill. The method comprises depositing a first TiN layer by exposing a substrate surface with at least one feature therein to a titanium amide precursor. A second TiN layer is deposited by exposing the first TiN layer to a titanium precursor and a nitrogen-containing plasma. The first and second TiN layers combine to fill the at least one feature with a gapfill material substantially free of any defects. Additional embodiments of the disclosure are directed to a method of depositing titanium nitride gapfill. The method comprises depositing a first TiN layer by thermal decomposition by exposing a substrate surface with at least one feature therein to TDMAT; the first TiN layer being amorphous. A second TiN layer is deposited by exposing the first TiN layer to a plurality of cycles comprising a deposition phase and treatment phase, the deposition phase comprising TDMAT, the treatment phase comprising a nitrogen-containing plasma. The first and second TiN layers combine to fill the at least one feature with a majority crystalline TiN gapfill material which is substantially free of any defects. BRIEF DESCRIPTION OF THE DRAWINGS So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. FIG. 1 illustrates a process flow of a gapfill method in accordance with one or more embodiments of the disclosure; and FIGS. 2A and 2B illustrate TEM images of resulting GAA semiconductor substrates according to exemplary embodiments of the disclosure. To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION Before describing several exemplary embodiments of the disclosure, it is to be understood that the disclosure is not limited to the details of construction or process steps set forth in the following description. The disclosure is capable of other embodiments and of being practiced or being carried out in various ways. As used in this specification and the appended claims, the term “substrate” refers to a surface, or portion of a surface, upon which a process acts. It will also be understood by those skilled in the art that reference to a substrate can also refer to only a portion of the substrate, unless the context clearly indicates otherwise. Additionally, reference to depositing on a substrate can mean both a bare substrate and a substrate with one or more films or features deposited or formed thereon A “substrate” as used herein, refers to any substrate or material surface formed on a substrate upon which film processing is performed during a fabrication process. For example, a substrate surface on which processing can be performed include materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon doped silicon oxides, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application