Method of depositing a silicon carbide layer
By combining soft plasma and strong plasma, silicon carbide layers are deposited on substrates, solving the problems of deposition uniformity and low dielectric constant in hollow features. This results in low-density silicon carbide layers with low dielectric constants, suitable for semiconductor device structures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ASM IP HLDG BV
- Filing Date
- 2025-11-24
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies struggle to deposit a uniform silicon carbide layer within hollow features on a substrate, especially when low dielectric constant requirements are needed.
A silicon carbide layer is deposited on a substrate using a combination of soft plasma and strong plasma. The substrate surface is opened to approach the hollow feature. Soft plasma provides reactive materials, and then strong plasma is used to improve the uniformity and quality of the layer.
A uniform silicon carbide layer with low density and low dielectric constant was deposited within the hollow feature, making it suitable for use as a spacer.
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Figure CN122105356A_ABST
Abstract
Description
Technical Field
[0001] This disclosure generally relates to depositing a silicon carbide layer on a substrate. More specifically, this disclosure relates to using plasma to deposit silicon carbide (SiC). Background Technology
[0002] Semiconductor manufacturing processes used to form semiconductor device structures (such as transistors, memory elements, and integrated circuits) are extensive and may include deposition processes. A deposition process may involve depositing a silicon carbide (SiC) layer on a substrate.
[0003] Structures on the substrate may include hollow features accessible via openings in the substrate surface. The deposition process of silicon carbide layers on the substrate can become challenging if the deposited layer needs to be deposited inside the hollow feature via the opening and the layer needs to have a uniform thickness.
[0004] Atomic layer deposition (ALD) processes can be used to achieve these conformal, uniform layers; however, silicon carbide layers are difficult to achieve with ALD to achieve good quality. Layers can be applied as spacers, where the dielectric constant of the layer can be a significant quality factor. It can be difficult to find layers with sufficiently low dielectric constants.
[0005] Therefore, there is a need for a deposition process for silicon carbide that can also achieve a uniform layer within the hollow features on the substrate. Summary of the Invention
[0006] This summary is provided to present the chosen concepts in a simplified form. These concepts are further described in detail in the following description of exemplary embodiments of this disclosure. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.
[0007] In at least one embodiment of the present invention, a method for depositing a silicon carbide layer on a substrate is provided. The method may include: providing a substrate in a reaction chamber; providing precursors and reactants (e.g., hydrogen) in the reaction chamber and forming a soft plasma in the reaction chamber; purging the reaction chamber; and providing an inert gas in the reaction chamber and forming a strong plasma with a power greater than that of the soft plasma. The soft plasma can help provide reactive materials for the precursors and reactants, enabling the provision of a uniform layer with good growth on the substrate. The strong plasma can further improve the quality of the uniform layer and ultimately form a uniform layer.
[0008] In at least one embodiment of the invention, the substrate may include a hollow feature accessible via an opening in the substrate surface, and the soft plasma provides reactive materials of precursors and reactants within the hollow feature via the opening. Having reactive materials provided through the opening can help provide a uniform layer within the hollow feature.
[0009] In at least one embodiment of the present invention, the deposition density can be between 1.7 and 2.1 g / cm³. 3 The layers between them. Having such low density can result in layers with low k values, which is advantageous.
[0010] For the purpose of summarizing the advantages of the present invention and its implementation relative to prior art, certain objects and advantages of the present invention have been described above. It should be understood, of course, that not all of these objects or advantages may be achieved according to any particular embodiment of the present invention. Therefore, for example, those skilled in the art will recognize that the present invention may be implemented or performed in a manner that achieves or optimizes one or more advantages as taught or suggested herein, without necessarily achieving other objects or advantages as may be taught or suggested herein.
[0011] All these embodiments are intended to fall within the scope of the invention disclosed herein. These and other embodiments will become apparent to those skilled in the art from the following detailed description of certain embodiments with reference to the accompanying drawings, and the invention is not limited to any particular embodiment disclosed. Attached Figure Description
[0012] Although this specification concludes with claims that are particularly pointed out and clearly claimed as embodiments of the invention, the advantages of the embodiments of this disclosure can be more readily determined from the description of certain examples of embodiments of the present disclosure when read in conjunction with the accompanying drawings, wherein:
[0013] Figure 1 A non-limiting exemplary process flow is shown, illustrating a method for depositing a silicon carbide layer on a substrate.
[0014] Figure 2a , Figure 2b and Figure 2c It shows that it can be used Figure 1 The structural formula of the precursor in the method.
[0015] The illustrations presented herein are not intended to be actual views of any particular material, structure, or device, but are merely idealized representations used to describe embodiments of this disclosure. Detailed Implementation
[0016] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that the invention extends beyond the specific disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Therefore, it is intended that the scope of the disclosed invention should not be limited to the specific disclosed embodiments described below.
[0017] As used herein, the term “substrate” can refer to any one or more underlying materials on which devices, circuits or layers may be formed or on which they may be used.
[0018] As used herein, the term “cyclic chemical vapor deposition” can refer to any process in which a substrate is sequentially exposed to one or more volatile precursors, which react and / or decompose on the substrate to produce the desired deposition.
[0019] As used herein, the term precursor may refer to a precursor used for depositing silicon carbide. Precursors may include silicon, oxygen, hydrogen, nitrogen, and carbon atoms.
[0020] As used herein, the term precursor may refer to a precursor containing a substituent selected from acetoxy, acryloyloxy, siloxy, germanoxy, phosphonoyloxy, and alkylamine groups.
[0021] As used herein, the term precursor may refer to a precursor that contains alkoxy groups (e.g., ethoxy groups). A precursor may contain 2 to 6 ethoxy groups.
[0022] As used herein, the term precursor may refer to a selection from 1,1,3,3,5,5-hexaethoxy-1,3,5-trisilylonhexane (C 15 H 36 O6Si3), methacryloyloxymethyltriethoxysilane (C 11 H 22 O5Si) and 1,3-diethoxy-1,2-dimethyl-1,3-disiloxane (C8H 20 The precursor of O2Si2).
[0023] As used herein, the term plasma can refer to a state of matter characterized by the presence of a large number of charged particles in any combination of ions or electrons.
[0024] As used herein, the term reactant may refer to a gas containing hydrogen, oxygen, nitrogen, or any mixture thereof.
[0025] As used herein, the term "atomic layer deposition" (ALD) can refer to a vapor-phase deposition process in which deposition cycles, preferably multiple consecutive cycles, are performed in a reaction chamber. Typically, during each cycle, a precursor is chemisorbed onto the deposition surface (e.g., a substrate surface or a previously deposited lower layer surface, such as material from a previous ALD cycle), forming a monolayer or sub-monolayer that is not readily reactive with another precursor (i.e., a self-limiting reaction). Subsequently, if desired, a reactant (e.g., another precursor or reactive gas) can be introduced into a processing chamber to convert the chemisorbed precursor into the desired material on the deposition surface. Typically, this reactant is capable of further reacting with the precursor. Furthermore, a purging step can be utilized during each cycle to remove excess precursor from the processing chamber and / or excess reactant and / or reaction byproducts after the conversion of the chemisorbed precursor. Furthermore, as used herein, the term “atomic layer deposition” is also intended to include processes specified by related terms such as “chemical vapor deposition,” “atomic layer epitaxy” (ALE), molecular beam epitaxy (MBE), gas source MBE or organometallic MBE, and chemical beam epitaxy when performed with alternating pulses of a precursor composition, a reactive gas, and a purge gas (e.g., an inert carrier gas).
[0026] As used herein, the terms “layer” and “thin layer” can refer to any continuous or discontinuous structure and material formed by the methods disclosed herein. For example, “layer” and “thin layer” can include 2D materials, nanolaminated materials, nanorods, nanotubes, or nanoparticles, or even partially or entirely molecular layers, or partially or entirely atomic layers or atomic and / or molecular clusters. “Layer” and “thin layer” can include materials or layers with pinholes, but still at least partially continuous.
[0027] Numerous exemplary materials are presented throughout the embodiments of this disclosure. It should be noted that the chemical formulas given for each material should not be construed as limiting, and the non-limiting exemplary materials given should not be limited by the given exemplary stoichiometry.
[0028] Figure 1A method 100 for depositing a silicon carbide layer on a substrate is illustrated. In at least one embodiment of the invention, the method may include: providing a substrate 110 in a reaction chamber; providing precursors and reactants (e.g., hydrogen) 120 in the reaction chamber; and forming a soft plasma 130 in the reaction chamber. Steps 135 may be repeated until sufficient precursors and reactants are provided to the substrate. Thereafter, the method may continue to purge the reaction chamber 140. Again, if desired, steps 145, including the purging step, may now be repeated. The method may then include providing an inert gas in the reaction chamber and forming a strong plasma 150 with a power greater than that of the soft plasma. Again, steps 155 may now be repeated with the inclusion of a strong plasma. Soft plasma can help provide reactive materials for the precursors and reactants, enabling the provision of a uniform layer on the substrate. Strong plasma can further improve the quality of the uniform layer and ultimately form a uniform layer.
[0029] In at least one embodiment of the invention, the substrate may include a hollow feature accessible via an opening in the substrate surface, and the soft plasma provides reactive materials of precursors and reactants within the hollow feature via the opening. Having reactive materials provided through the opening can help provide a uniform layer within the hollow feature.
[0030] In at least one embodiment, the plasma can be a continuous-wave plasma. The continuous-wave plasma can have suitable properties to activate the precursor.
[0031] In at least one embodiment, the strong plasma has a power 10 to 2 times higher, preferably 7 to 2.5 times higher, and more preferably 5 to 3 times higher than that of the soft plasma. For example, the soft plasma can have a power between 5 and 100 watts, preferably between 10 and 50 watts, and more preferably between 20 and 35 watts. For example, the strong plasma can have a power between 50 and 200 watts, preferably between 75 and 150 watts, and most preferably between 90 and 125 watts. With these powers, the soft plasma may be strong enough to activate precursors and reactants, but may be too weak to damage them. The strong plasma can solidify and / or improve already deposited layers. That is, a layer that has already been deposited can also be protected from damage by the strong plasma.
[0032] In at least one embodiment, a silicon carbide layer may be deposited. The presence of oxygen may be beneficial for some applications.
[0033] In at least one embodiment, the precursor comprises a substituent selected from acetoxy, acryloyloxy, siloxy, germanoxy, phosphonoyloxy, and alkylamine groups. These groups can impart the correct chemical properties while providing the desired reactivity.
[0034] In one embodiment, the precursor comprises an alkoxy group. The alkoxy group may comprise an ethoxy group. The precursor may contain 2 to 6 ethoxy groups.
[0035] Figure 2a , Figure 2b and Figure 2c It shows the use of Figure 1 The method provides the structural formula of the precursor. In one embodiment, the precursor may be selected from 1,1,3,3,5,5-hexaethoxy-1,3,5-trisilylonhexane (C 15 H 36 O6Si3)(see also Figure 2a ), Methacryloxymethyltriethoxysilane (C 11 H 22 O5Si)(see also Figure 2b ) and 1,3-diethoxy-1,2-dimethyl-1,3-disilhecyclobutane (C8H 20 O2Si2)(see also Figure 2c ).
[0036] In one embodiment, the precursor may include silicon, oxygen, hydrogen, nitrogen, and carbon atoms. This brings the correct chemical properties into the layer.
[0037] In one embodiment, the reactants may comprise hydrogen, oxygen, nitrogen, or any mixture thereof. The reactants may be activated by plasma.
[0038] In one embodiment, the inert gas forming the plasma includes a gas selected from argon, helium, neon, krypton, and xenon. The inert gas can be activated by the plasma without reacting with the deposited layer.
[0039] In one embodiment, the plasma contains nitrogen. This enables the deposition of nitrogen in the deposition layer.
[0040] In one embodiment, a silicon carbide nitride layer is deposited. The presence of oxygen and nitrogen may be beneficial for some applications.
[0041] In one embodiment, a silicon carbonitride layer is deposited. The presence of nitrogen may be beneficial for some applications.
[0042] In one embodiment, the method includes providing a strong plasma after:
[0043] Purge the reaction chamber;
[0044] Precursors and reactants are provided in the reaction chamber, and soft plasma is formed in the reaction chamber;
[0045] Purge the reaction chamber; and
[0046] An inert gas is provided in the reaction chamber, and a powerful plasma with greater power than soft plasma is formed within the chamber. In this way, the layer can be constructed from multiple silicon carbide layers.
[0047] Table 1 (below) depicts some properties of layers deposited using the precursor 1,1,3,3,5,5-hexaethoxy-1,3,5-trisilycyclohexane and hydrogen as reactants. According to the invention, the precursor, reactants, and soft plasma are supplied for 1 second, purging for 5 seconds, and strong plasma for 0.3 seconds. The soft plasma has a power of 25 to 35 watts, and the strong plasma has a power of 100 watts. The growth rate per cycle is 0.6–3.2 Å / cycle. Layers deposited using this method can have properties of 1.7 and 2.1 g / cm³. 3 The density between and a k value of approximately 3.5.
[0048]
[0049] Low density indicates high porosity. High porosity imparts a low dielectric constant (i.e., a low k-value) to the layer because air has a relatively low dielectric constant, which is advantageous in applications where the layer is used as a spacer.
[0050] In existing technology examples, a plasma with a power of 100 to 300 watts is sustained for 0.5 to 2 seconds. The growth rate per cycle is 0.06 to 0.14 Å / cycle. Layers deposited using this method can have g / cm³ values of 2.23 and 2.35 g / cm³. 3 The density between and a k value of approximately 3.8.
[0051] The exemplary embodiments of this disclosure described above do not limit the scope of the invention, as these embodiments are merely examples of embodiments of the invention defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to fall within the scope of the invention. In fact, various modifications to this disclosure, such as alternative useful combinations of the elements, in addition to those shown and described herein, will become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims.
Claims
1. A method for depositing a silicon carbide layer on a substrate, the method comprising: Provide a substrate in the reaction chamber; Precursors and reactants are provided in the reaction chamber, and soft plasma is formed in the reaction chamber; Purge the reaction chamber; as well as An inert gas is provided in the reaction chamber, and a strong plasma with greater power than soft plasma is formed in the reaction chamber.
2. The method according to claim 1, wherein, The substrate includes a hollow feature accessible via an opening in the substrate surface, and the soft plasma provides the precursor and the reactant reactive material within the hollow feature via the opening.
3. The method according to claim 1, wherein, The plasma is a continuous wave plasma.
4. The method according to claim 1, wherein, The strong plasma has a power that is 10 to 2 times higher, preferably 7 to 2.5 times higher, and more preferably 5 to 3 times higher than that of the soft plasma.
5. The method according to claim 4, wherein, The soft plasma has a power between 5 and 100 watts, preferably between 10 and 50 watts, and more preferably between 20 and 35 watts.
6. The method according to claim 4, wherein, The strong plasma has a power between 50 and 200 watts, preferably between 75 and 150 watts, and most preferably between 90 and 125 watts.
7. The method according to claim 1, wherein, Deposit a silicon dioxide layer.
8. The method according to claim 1, wherein, The precursor contains substituents selected from acetoxy, acryloyloxy, siloxy, germanoxy, phosphonoyloxy, and alkylamine groups.
9. The method according to claim 1, wherein, The precursor contains an alkoxy group.
10. The method according to claim 9, wherein, The alkoxy group includes the ethoxy group.
11. The method according to claim 9, wherein, The precursor contains 2 to 6 ethoxy groups.
12. The method according to claim 9, wherein, The precursor is selected from 1,1,3,3,5,5-hexaethoxy-1,3,5-trisilylonhexane (C 15 H 36 O6Si3), methacryloyloxymethyltriethoxysilane (C 11 H 22 O5Si) and 1,3-diethoxy-1,2-dimethyl-1,3-disiloxane (C8H 20 O2Si2).
13. The method according to claim 1, wherein, The precursor contains silicon, oxygen, hydrogen, nitrogen, and carbon atoms.
14. The method according to claim 1, wherein, The reactants include hydrogen, oxygen, nitrogen, or any mixture thereof.
15. The method according to claim 1, wherein, The inert gases that form the plasma include those selected from argon, helium, neon, krypton, and xenon.
16. The method according to claim 1, wherein, The plasma contains nitrogen.
17. The method according to claim 16, wherein, Deposit a layer of silicon nitride carbon oxide.
18. The method according to claim 16, wherein, Deposit silicon carbonitride.
19. The method according to claim 18, wherein, The silicon carbide nitride layer contains less than 5% carbon.
20. The method according to claim 1, wherein, The method includes, after providing the strong plasma: Purge the reaction chamber; The precursor and the reactant are provided in the reaction chamber, and a soft plasma is formed in the reaction chamber; Purge the reaction chamber; as well as An inert gas is provided in the reaction chamber, and a strong plasma with greater power than soft plasma is formed in the reaction chamber.
21. A layer deposited using the method according to claim 1, wherein, Layer density is between 1.7 and 2.1 g / cm³ 3 between.