Ru thin-film deposition process
Patent Information
- Application Number
- PCT/CN2026/077268
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-26
- Filing Date
- 2026-02-05
- Publication Date
- 2026-09-03
Smart Images
Figure CN2026077268_03092026_PF_FP_ABST
Abstract
Description
Ru thin film deposition process
[0001] Cross-reference of related applications
[0002] This disclosure claims priority to Chinese Patent Application No. 2025102227906, entitled "Ru Thin Film Deposition Process", filed on February 26, 2025, with the China National Intellectual Property Administration, the entire contents of which are incorporated herein by reference. Technical Field
[0003] This application relates to the field of semiconductor technology, and more specifically, to a Ru thin film deposition process. Background Technology
[0004] Ru (ruthenium) is a rare and precious metal belonging to the platinum group elements. Due to its excellent physical and chemical properties, Ru films have wide applications in many high-tech fields, especially in microelectronics, magnetic storage, catalysts, and sensors. Currently, when depositing Ru thin films on silicon substrates using atomic layer deposition (ALD), the nucleation cycle is relatively long, resulting in low process efficiency. Summary of the Invention
[0005] This application provides a Ru thin film deposition process that can provide Ru thin film deposition efficiency.
[0006] The embodiments of this application are implemented as follows:
[0007] This application provides a Ru thin film deposition process, including:
[0008] A metal-organic compound layer is formed by depositing metal-organic compound precursor materials on the surface of a silicon substrate.
[0009] The silicon substrate was purged using an inert gas.
[0010] A Ru thin film was deposited on the metal-organic compound layer using an atomic layer deposition process.
[0011] In an optional embodiment, the step of depositing a metal-organic compound layer on the surface of a silicon substrate using a metal-organic compound precursor material includes:
[0012] The organometallic precursor material is heated to make its saturated vapor pressure greater than 1 torr;
[0013] The organometallic precursor material is introduced along with a carrier gas into a reaction chamber containing the silicon substrate, so as to deposit the organometallic layer on the surface of the silicon substrate.
[0014] In an optional embodiment, the pressure in the reaction chamber is 0.5 to 3 torr.
[0015] In an optional embodiment, the temperature of the silicon substrate during the deposition of the metal-organic compound layer and the Ru thin film is 230~300°C.
[0016] In an optional embodiment, in the step of depositing a metal-organic compound layer on the surface of a silicon substrate using a metal-organic compound precursor material, a mask is used to cover a local area of the silicon substrate, and the metal-organic compound layer is deposited on the exposed surface of the silicon substrate.
[0017] In an optional embodiment, the organometallic precursor material is selected from at least one of organometallic precursor materials containing tetra(methylethylamino), organometallic precursor materials containing tetra(dimethylamino), and organometallic precursor materials containing bis(diethylamino).
[0018] In an optional embodiment, the organometallic precursor material is selected from at least one of TEMAHf, TEMAZr, TDMAT, and BDEAS.
[0019] In an optional embodiment, the step of depositing a Ru thin film on the organometallic compound layer by an atomic layer deposition process includes:
[0020] Ru precursor and oxidant are introduced into a reaction chamber for reaction deposition, and then the remaining reactants are purged with an inert gas. This process is repeated multiple times to form the Ru film.
[0021] In an optional embodiment, the Ru precursor and the oxidant are bis(ethylcyclopentadiene)ruthenium and oxygen, respectively.
[0022] In an optional implementation, the total number of cycles for depositing the Ru film using an atomic layer deposition process does not exceed 800.
[0023] In an optional embodiment, the silicon substrate is made of silicon or silicon oxide.
[0024] In the Ru thin film deposition process provided in this application embodiment, a metal-organic compound (MOC) layer is formed on the surface of a silicon substrate by depositing a metal-organic compound precursor material. Since the MOC precursor material readily forms physical adsorption with the silicon substrate, the bonding force between the two is excellent. Simultaneously, the organic groups in the MOC layer easily combine with the Ru precursor used in subsequent Ru film fabrication. Therefore, the MOC layer acts as an intermediary layer, increasing the adsorption density of the Ru precursor on the substrate (specifically, on the MOC layer), thereby enhancing the nucleation density. At a higher nucleation density, the nucleation efficiency is improved, thus reducing the total number of cycles required for atomic layer deposition (ALD) of the Ru thin film. Attached Figure Description
[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 is a flowchart of a Ru thin film deposition process in one embodiment of this application;
[0027] Figure 2 shows the relationship between the number of cycles and the thickness of the Ru film when Ru films were prepared using the embodiments and comparative examples of this application. Embodiments of the present invention
[0028] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.
[0029] In the fabrication of Ru thin films using related processes, atomic layer deposition (ALD) is performed using a Ru precursor (such as diethylcyclopentadiene ruthenium Ru(EtCp)2) and an oxidant. However, this process involves a long nucleation cycle when depositing Ru films on silicon-based substrates (such as Si / SiO2 substrates), potentially requiring thousands of cycles to achieve nucleation, resulting in low process efficiency. Furthermore, the long nucleation cycle restricts the growth of Ru films in localized areas during the initial growth phase. Additionally, because the adsorption of the Ru precursor on the Ru nuclei is superior to that on the substrate surface, the deposited film exhibits a high roughness, leading to poor uniformity and low quality.
[0030] To address at least one deficiency in the aforementioned related technologies, this application provides a Ru thin film deposition process. By pretreating the silicon substrate before atomic layer deposition of the Ru thin film, a metal-organic compound layer is first formed on the surface of the silicon substrate. This results in a shorter nucleation cycle during subsequent atomic layer deposition of the Ru thin film, improving the preparation efficiency of the Ru thin film and also facilitating the acquisition of a more uniform Ru thin film.
[0031] The Ru thin film deposition process of the embodiments of this application will be described in detail below.
[0032] Figure 1 is a flowchart of a Ru thin film deposition process in one embodiment of this application. As shown in Figure 1, the Ru thin film deposition process provided in this embodiment includes the following steps:
[0033] Step S100: A metal-organic compound layer is deposited on the surface of a silicon substrate using a metal-organic compound precursor material.
[0034] In this embodiment, this step is equivalent to a pretreatment process performed on the silicon substrate before Ru film deposition. The organometallic precursor material readily forms good physical adsorption with the silicon substrate, resulting in a strong bond between the formed organometallic layer and the silicon substrate. This is due to the excellent bonding ability between the organic groups in the organometallic precursor material and the silicon substrate material. For the same reason, the organometallic precursor material also readily bonds with the Ru precursor used in the subsequent Ru film fabrication. Therefore, the organometallic layer can act as an intermediary layer, increasing the adsorption density of the Ru precursor, thereby effectively improving the nucleation density, enhancing the nucleation efficiency, shortening the nucleation cycle, and promoting the formation of a continuous Ru film.
[0035] Optionally, the organometallic precursor material is selected from at least one of organometallic precursor materials containing tetra(methylethylamino), organometallic precursor materials containing tetra(dimethylamino), and organometallic precursor materials containing bis(diethylamino). Tetra(methylethylamino) contains four -N(CH3)(C2H5) groups, tetra(dimethylamino) contains four -N(CH3)2 groups, and bis(diethylamino) contains two -N(C2H5)2 groups.
[0036] Optionally, the silicon-based substrate is made of silicon or silicon oxide. Tetra(methylethylamino), tetra(dimethylamino), and bis(diethylamino) have good bonding ability with silicon / silicon oxide, and are therefore easy to combine.
[0037] Optionally, the organometallic precursor material is selected from at least one of TEMAHf (Hf[N(C2H5)(CH3)]4), TEMAZr (Zr[N(C2H5)(CH3)]4), TDMAT (Ti[N(CH3)2]4), and BDEAS (SiH2[N(C2H5)2]2).
[0038] Optionally, step S100 specifically includes the following steps:
[0039] Step S110: Heat the organometallic precursor material to make its saturated vapor pressure greater than 1 torr;
[0040] In step S120, the organometallic precursor material is introduced into the reaction chamber containing the silicon substrate along with the carrier gas, so as to deposit an organometallic layer on the surface of the silicon substrate.
[0041] In this embodiment, step S100 and subsequent steps S200 and S300 are all performed in the same reaction chamber. Specifically, in step S110, the container configured to store the organometallic precursor material can be heated to raise its temperature to a target temperature, where the saturated vapor pressure of the organometallic precursor material at that target temperature is greater than 1 torr.
[0042] In step S120, the carrier gas can be argon and / or nitrogen, or other inert gases that do not participate in the reaction. The flow rate of the carrier gas can be selected as 200~400 sccm, and the duration of introduction into the reaction chamber together with the organometallic precursor material can be selected as 0.5~1s.
[0043] Optionally, during the deposition of the metal-organic compound layer, the pressure in the reaction chamber is 0.5 to 3 torr, and the temperature of the silicon substrate is 230 to 300°C.
[0044] Step S200: The silicon substrate is purged with an inert gas.
[0045] In the embodiments of this application, argon and / or nitrogen can be used to purge the silicon substrate to remove the metal-organic compound precursor material around the silicon substrate, preparing it for subsequent Ru film deposition.
[0046] Depositing metal-organic compound (MOC) layers on silicon substrates can be achieved through direct adsorption, where the MOC precursor material (gas) is exposed to the silicon substrate surface to form a monolayer; or through atomic layer deposition (ALD), for example, by repeatedly adsorbing the MOC precursor material, purging with an inert gas, and treating with a reducing gas plasma (such as NH3 or H2 plasma) to form an ultrathin MOC layer. Optionally, the thickness of the MOC layer can be 0.03–2.0 nm.
[0047] Step S300: Deposit a Ru thin film on the metal-organic compound layer using an atomic layer deposition process.
[0048] In this embodiment, the specific method of depositing a Ru thin film using atomic layer deposition (ALD) can refer to conventional prior art. In this embodiment, the step includes introducing a Ru precursor and an oxidant into a reaction chamber for reaction deposition, followed by purging of the remaining reactants with an inert gas (such as argon and / or nitrogen), repeated multiple times to form a Ru thin film. The inert gas prevents gas-phase reactions between reactants and achieves a self-saturating surface reaction. However, in some embodiments, the silicon substrate can be moved to separately contact the reactants (such as the Ru precursor and oxidant). Because the reaction is self-saturating, strict temperature control of the silicon substrate and precise dosage control of the Ru precursor are generally not required. However, the silicon substrate temperature can optionally prevent the accompanying gases from condensing into a monolayer or decomposing on the surface. Before contacting the silicon substrate with the next reactant, the remaining reactants and reaction byproducts (if present) are removed from the silicon substrate surface, such as by purging the reaction space or by moving the silicon substrate. Unwanted gaseous substances can be effectively removed from the reaction space using an inert gas, which can be assisted by a vacuum pump. Optionally, the Ru precursor and oxidant are diethylcyclopentadiene ruthenium (i.e., Ru(EtCp)2) and oxygen, respectively. In this embodiment, Ru(EtCp)2 can bind well with materials such as TEMAHf, TEMAZr, TDMAT, and BDEAS, thus exhibiting a high adsorption density on the organometallic compound layer, thereby increasing the nucleation density, shortening the nucleation cycle, and improving the deposition efficiency.
[0049] During the Ru film deposition process, the temperature of the silicon substrate is maintained at 230~300°C. Because the Ru film deposition process provided in this application has a short nucleation cycle, the total number of deposition cycles can be significantly reduced. Optionally, the total number of Ru film deposition cycles using atomic layer deposition (ALD) does not exceed 800; using the Ru film deposition process provided in this application, a Ru film with a thickness of 200 angstroms or more can be formed even with a total number of cycles below 800.
[0050] In this embodiment, a mask can be used to selectively cover a portion of a silicon substrate, and a metal-organic compound layer and a Ru thin film can be deposited on the exposed surface of the silicon substrate to form a patterned Ru thin film. In other optional embodiments, a Ru thin film can be formed first, then a photoresist pattern can be applied over the Ru thin film, and the Ru thin film exposed by the photoresist pattern can be etched to form a patterned Ru thin film.
[0051] The effects of the Ru thin film deposition process of this application will be described below with reference to specific embodiments and comparative examples.
[0052] Example 1
[0053] TEMAHf was heated to 90°C, where its saturated vapor pressure is greater than 1 torr. Ar gas carrying TEMAHf vapor was injected into the reaction chamber to pretreat the silicon substrate surface. The carrier gas flow rate was 300 sccm, and the injection time was 0.5 s. Subsequently, Ar gas was used to purge the silicon substrate surface to remove excess TEMAHf, allowing a uniform saturated layer of TEMAHf to adsorb onto the substrate surface, forming a metal-organic compound layer. The silicon substrate temperature was set at 230°C, and the pressure was controlled at 0.5 torr. Ru (EtCp)₂ and oxygen were used to deposit a Ru thin film on the metal-organic compound layer using atomic layer deposition (ALD). In the above deposition steps, the nucleation cycle was 68 cycles, and after 500 cycles, the Ru film thickness reached 269 angstroms, with a thickness uniformity of 0.43%.
[0054] Example 2
[0055] TEMAZr was heated to 92°C, where its saturated vapor pressure is greater than 1 torr. Ar gas, carrying TEMAZr vapor, was injected into the reaction chamber to pretreat the silicon substrate surface. The carrier gas flow rate was 300 sccm, and the injection time was 1 s. Subsequently, Ar gas was used to purge the silicon substrate surface to remove excess TEMAZr, allowing a uniform saturated layer of TEMAZr to adsorb onto the substrate surface, forming a metal-organic compound layer. The silicon substrate temperature was set at 260°C, and the pressure was controlled at 1 torr. Ru (EtCp)₂ and oxygen were used to deposit a Ru thin film on the metal-organic compound layer using atomic layer deposition (ALD). In the above deposition steps, the nucleation cycle was 69 cycles, and after 500 cycles, the Ru film thickness reached 266 angstroms, with a thickness uniformity of 0.43%.
[0056] Example 3
[0057] TDMAT was heated to 93°C, where its saturated vapor pressure is greater than 1 torr. Ar gas, carrying TDMAT vapor, was injected into the reaction chamber to pretreat the silicon substrate surface. The carrier gas flow rate was 300 sccm, and the injection time was 0.8 s. Subsequently, Ar gas was used to purge the silicon substrate surface to remove excess TDMAT, allowing a uniform saturated TDMAT layer to be adsorbed, forming a metal-organic compound layer. The silicon substrate temperature was set at 280°C, and the pressure was controlled at 2 torr. Ru (EtCp)₂ and oxygen were used to deposit a Ru thin film on the metal-organic compound layer using atomic layer deposition (ALD). In the above deposition steps, the nucleation cycle was 77 cycles, and after 500 cycles, the Ru film thickness reached 253 angstroms, with a thickness uniformity of 0.45%.
[0058] Example 4
[0059] BDEAS was heated to 95°C, where its saturated vapor pressure is greater than 1 torr. Ar gas, carrying BDEAS vapor, was injected into the reaction chamber to pretreat the silicon substrate surface. The carrier gas flow rate was 300 sccm, and the injection time was 1 s. Subsequently, Ar gas was used to purge the silicon substrate surface to remove excess BDEAS, allowing a uniform saturated layer of BDEAS to adsorb onto the substrate surface, forming a metal-organic compound layer. The silicon substrate temperature was set at 300°C, and the pressure was controlled at 3 torr. A Ru thin film was deposited on the metal-organic compound layer using Ru(EtCp)₂ and oxygen via atomic layer deposition. In the above deposition steps, the nucleation cycle was 122 cycles, and after 500 cycles, the Ru film thickness reached 227 angstroms, with a thickness uniformity of 0.49%.
[0060] Comparative Example 1
[0061] The difference from Example 1 is that no pretreatment was performed on the silicon substrate, and Ru thin film was directly deposited on the silicon substrate using atomic layer deposition process.
[0062] Comparative Example 2
[0063] The difference from Example 1 is that the step of depositing a metal-organic compound layer using TEMAHf is omitted, and instead, the silicon substrate is treated with ozone for 10 minutes at an ozone concentration of 280 g / m³. 3 The flow rate was 5000 sccm. Subsequently, Ru thin films were deposited using atomic layer deposition (ALD).
[0064] Comparative Example 3
[0065] The difference from Example 1 is that the step of depositing a metal-organic compound layer using TEMAHf is omitted, and instead, the silicon substrate is treated with ammonia gas for 10 minutes at a flow rate of 5000 sccm. Subsequently, a Ru thin film is deposited using atomic layer deposition.
[0066] Comparative Example 4
[0067] The difference from Example 1 is that the step of depositing a metal-organic compound layer using TEMAHf is omitted. Instead, the silicon substrate is first treated with ozone for 10 minutes, followed by treatment with ammonia for 10 minutes, wherein the ozone concentration is 280 g / m³. 3 The flow rate was 5000 sccm, and the ammonia flow rate was also 5000 sccm. Subsequently, a Ru thin film was deposited using atomic layer deposition (ALD).
[0068] Comparative Example 5
[0069] The difference from Example 1 is that the step of depositing a metal-organic compound layer using TEMAHf is omitted. Instead, the silicon substrate is first treated with ammonia for 10 minutes, followed by ozone treatment for 10 minutes, wherein the ozone concentration is 280 g / m³. 3 The flow rate was 5000 sccm, and the ammonia flow rate was 5000 sccm. Subsequently, a Ru thin film was deposited using atomic layer deposition (ALD).
[0070] Figure 2 shows the relationship between the number of cycles and the thickness of the Ru film when Ru films were prepared using the embodiments and comparative examples of this application. In Figure 2, the vertical axis represents the thickness of the Ru film (THK) in angstroms, and the horizontal axis represents the number of cycles in the atomic layer deposition process.
[0071] As shown in Figure 2, in Comparative Example 1 where the silicon substrate was not pretreated, the nucleation cycle was 1053 cycles. After 1400 cycles of deposition, the thickness reached 213 angstroms, and the thickness uniformity of the Ru film was 2.15%.
[0072] In Comparative Example 2, the nucleation cycle was 1043 cycles, and after 1400 cycles of deposition, the thickness reached 216 angstroms, and the thickness uniformity of the Ru film was 2.08%.
[0073] In Comparative Example 3, the nucleation cycle was 1038 cycles, and after 1400 cycles of deposition, the thickness reached 225 angstroms, and the thickness uniformity of the Ru film was 2.21%.
[0074] In Comparative Example 4, the nucleation cycle was 1041 cycles, and after 1400 cycles of deposition, the thickness reached 217 angstroms, and the thickness uniformity of the Ru film was 2.37%.
[0075] In Comparative Example 5, the nucleation cycle was 977 cycles, and after 1400 cycles of deposition, the thickness reached 257 angstroms, and the thickness uniformity of the Ru film was 2.01%.
[0076] As can be seen, in each comparative example, the nucleation cycle for depositing Ru films is relatively long. For films of similar thickness, the total number of deposition cycles in each comparative example exceeds one thousand, significantly higher than the total number of cycles in Examples 1-4. Therefore, the Ru film deposition process of this application can effectively improve the deposition efficiency of Ru films. Furthermore, from the perspective of thickness uniformity, the thickness uniformity of the Ru films in each embodiment of this application is below 0.5%, with a lower value indicating a more uniform Ru film thickness. In contrast, the thickness uniformity of the Ru films obtained in Comparative Examples 1-5 is above 2%. Therefore, from the perspective of thickness uniformity, the Ru film deposition process provided by this application can effectively improve the quality of Ru films.
[0077] In summary, this application provides a Ru thin film deposition process, including depositing a metal-organic compound (MOC) layer on the surface of a silicon substrate using a metal-organic compound precursor material; purging the silicon substrate with an inert gas; and depositing a Ru thin film on the MOC layer using atomic layer deposition (ALD). Since the MOC precursor material readily forms physical adsorption with the silicon substrate, the bonding force between them is excellent. Simultaneously, the organic groups in the MOC layer readily combine with the Ru precursor used in the subsequent Ru film fabrication. Therefore, the MOC layer acts as an intermediary layer, increasing the adsorption density of the Ru precursor on the substrate (specifically, the MOC layer), thereby enhancing the nucleation density. At a higher nucleation density, the nucleation efficiency is improved, thus reducing the total number of cycles required for ALD deposition of the Ru thin film.
[0078] The above description is merely a specific embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application. Industrial applicability
[0079] This application provides a Ru thin film deposition process that can improve nucleation efficiency at higher nucleation densities, thereby reducing the total number of cycles required to deposit Ru thin films using atomic layer deposition processes.
Claims
1. A Ru thin film deposition process, characterized in that, include: A metal-organic compound layer is formed by depositing metal-organic compound precursor materials on the surface of a silicon substrate. The silicon substrate was purged using an inert gas. A Ru thin film was deposited on the metal-organic compound layer using an atomic layer deposition process.
2. The Ru thin film deposition process according to claim 1, characterized in that, The step of depositing a metal-organic compound layer on the surface of a silicon substrate using a metal-organic compound precursor material includes: The organometallic precursor material is heated to make its saturated vapor pressure greater than 1 torr; The organometallic precursor material is introduced along with a carrier gas into a reaction chamber containing the silicon substrate, so as to deposit the organometallic layer on the surface of the silicon substrate.
3. The Ru thin film deposition process according to claim 2, characterized in that, The pressure in the reaction chamber is 0.5~3 torr.
4. The Ru thin film deposition process according to claim 2 or 3, characterized in that, The temperature during the deposition of the metal-organic compound layer and the Ru thin film on the silicon substrate is 230~300℃.
5. The Ru thin film deposition process according to any one of claims 1 to 4, characterized in that, In the step of depositing a metal-organic compound layer on the surface of a silicon substrate using a metal-organic compound precursor material, a mask is used to cover a local area of the silicon substrate, and the metal-organic compound layer is deposited on the exposed surface of the silicon substrate.
6. The Ru thin film deposition process according to any one of claims 1 to 5, characterized in that, The organometallic precursor material is selected from at least one of organometallic precursor materials containing tetra(methylethylamino), organometallic precursor materials containing tetra(dimethylamino), and organometallic precursor materials containing bis(diethylamino).
7. The Ru thin film deposition process according to claim 6, characterized in that, The organometallic precursor material is selected from at least one of TEMAHf, TEMAZr, TDMAT, and BDEAS.
8. The Ru thin film deposition process according to any one of claims 1 to 7, characterized in that, The step of depositing a Ru thin film on the organometallic compound layer by atomic layer deposition includes: Ru precursor and oxidant are introduced into the reaction chamber for reaction deposition, and then the remaining reactants are purged with inert gas. This process is repeated multiple times to form the Ru film.
9. The Ru thin film deposition process according to claim 8, characterized in that, The Ru precursor and the oxidant are respectively diethylcyclopentadiene ruthenium and oxygen.
10. The Ru thin film deposition process according to claim 8 or 9, characterized in that, The total number of cycles for depositing the Ru film using atomic layer deposition does not exceed 800.
11. The Ru thin film deposition process according to any one of claims 1 to 10, characterized in that, The silicon-based substrate is made of silicon or silicon oxide.