A medium film deposition process and plasma processing apparatus

Abstract

The application discloses a medium film deposition process and a plasma processing device, and at least comprises: a substrate with a recess structure, the substrate is placed in a reaction chamber; a first deposition step: a first medium layer with a first step coverage is deposited on the side wall and the bottom of the recess structure by using a CVD process; an inhibition step: a first processing gas is introduced into the reaction chamber to perform inhibition treatment on at least part of the opening area of the first medium layer; a second deposition step: a second medium layer with a second step coverage is deposited on the surface of the first medium layer after the inhibition treatment by using a first pulse CVD or ALD process; wherein the second step coverage is greater than the first step coverage. When thick film deposition is performed, not only a faster deposition rate is ensured, but also a high step coverage is realized, and the quality of the thin film is also improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a dielectric thin film deposition process and plasma processing equipment. Background Technology

[0002] In semiconductor thin film deposition processes, atomic layer deposition (ALD) is widely chosen because its unique self-limiting growth mechanism provides a series of precise control characteristics. ALD is achieved through two "half-reactions": saturated surface chemisorption and self-limiting reaction. As the number of ALD cycles increases, precise control of atomic-level thickness and high conformality (high step coverage) can be achieved.

[0003] With the miniaturization of semiconductor devices and the development of three-dimensional structures, thick films are often required to fill high aspect ratio structures. For thick film filling, not only must high fill capability be achieved, but also excellent step coverage must be obtained to meet the stringent requirements for film quality in the continuous miniaturization and high performance of semiconductor devices. However, in actual thick film (100nm and above) deposition, the deposition rate of atomic layer deposition processes is very slow, leading to a sharp increase in production efficiency and manufacturing costs.

[0004] The statements herein provide only background information in relation to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of traditional atomic layer deposition processes that make it difficult to simultaneously achieve high step coverage, high filling capacity, and faster deposition rate, and to provide a dielectric thin film deposition process and plasma processing equipment to meet the needs of thick film deposition applications.

[0006] To achieve the above objectives, the present invention provides a dielectric thin film deposition process, comprising at least: A substrate with a recessed structure is provided, and the substrate is placed inside a reaction chamber; First deposition step: Using a CVD process, a first dielectric layer with a first step coverage is deposited on the sidewalls and bottom of the recessed structure; Suppression step: A first processing gas is introduced into the reaction chamber to suppress at least a portion of the opening area of ​​the first medium layer. The first processing gas reacts with at least a portion of the material layer deposited on the sidewall of the recessed structure to form a suppression zone. Second deposition step: Using a first pulse CVD or ALD process, a second dielectric layer with a second step coverage is deposited on the surface of the first dielectric layer after the suppression treatment; The second step coverage rate is greater than the first step coverage rate.

[0007] Optionally, in the first deposition step, the CVD process is a pulsed CVD process.

[0008] Optionally, the step coverage of the first dielectric layer is greater than or equal to 50%.

[0009] Optionally, the duty cycle of the radio frequency pulse in the pulsed CVD process is 55-90%.

[0010] Optionally, the duty cycle of the radio frequency pulse in the pulsed CVD process is 10~50%.

[0011] Optionally, the process gas pressure of the pulsed CVD process is less than 10 torr.

[0012] Optionally, the pulsed CVD process includes a first frequency, which is greater than or equal to 13.56 MHz.

[0013] Optionally, the pulsed CVD process further includes a second frequency, which is less than or equal to 400 kHz.

[0014] Optionally, the step coverage of the second dielectric layer is greater than or equal to 95%.

[0015] Optionally, the process further includes a modification step: introducing a second processing gas into the reaction chamber, turning on the plasma source, exciting the second processing gas into active particles, and using the active particles to modify the first dielectric layer and / or the second dielectric layer to improve the film quality.

[0016] Optionally, the second processing gas is selected from at least one of inert gases, oxidizing gases, reducing gases, and nitrogen-containing gases.

[0017] Optionally, the modification step is performed on the first dielectric layer after the first deposition step.

[0018] Optionally, the dielectric thin film deposition process includes: Step S1: Deposit a first dielectric layer on the sidewalls and bottom of the recessed structure using CVD or pulsed CVD process; Step S2: A second processing gas is introduced into the reaction chamber to modify the first medium layer; Step S3: Introduce a first processing gas into the reaction chamber to suppress the first medium layer; Step S4: Deposit a second dielectric layer on the surface of the first dielectric layer after the suppression treatment using pulsed CVD or ALD process; The process involves repeating steps S1 to S2 N times, where N is an integer greater than 0.

[0019] Optionally, the modification step is performed on the second dielectric layer after the second deposition step.

[0020] Optionally, the first deposition step includes at least: introducing a first precursor gas and a second precursor gas into the reaction chamber, turning on the plasma source, and having the first precursor gas and the second precursor gas react to generate the first dielectric layer.

[0021] Optionally, the first precursor gas includes at least one of the following: metallic precursor gas, non-metallic precursor gas, and semiconductor precursor gas.

[0022] Optionally, the second precursor gas contains at least one of an oxidizing gas, a reducing gas, and a nitrogen-containing gas.

[0023] Optionally, in the suppression step, the first processing gas includes an inert gas and at least one of a nitrogen-containing gas and a fluorine-containing gas.

[0024] Optionally, the first processing gas includes at least one gas selected from NF3, N2, and NH3.

[0025] Optionally, the first dielectric layer and the second dielectric layer are any one of nitride, oxide, and oxynitride.

[0026] Optionally, after the first dielectric layer is formed, the suppression step and the second deposition step are repeated in a cycle until a dielectric film of the target thickness is formed.

[0027] Optionally, the cycle ratio of the suppression step and the second deposition step is 1:1 to 1:20.

[0028] Optionally, the target thickness is greater than or equal to 100 nm.

[0029] Accordingly, the present invention also provides a plasma processing apparatus, comprising: reaction chamber; The base, located within the reaction chamber, is used to support the substrate; A plasma source, used to excite and form plasma; The controller is configured to perform the dielectric thin film deposition process as described above.

[0030] Compared with the prior art, the beneficial effects of the technical solution of the present invention include at least the following: (1) The dielectric thin film deposition process of the present invention includes a first deposition step, a suppression step, and a second deposition step. In the first deposition step, a first dielectric layer with a step coverage of greater than or equal to 50% is first deposited on the sidewalls and bottom of the recessed structure using a CVD process. Further, a pulsed CVD process is used to deposit the first dielectric layer in the recessed structure with a high aspect ratio, so that the dielectric film has a faster deposition rate and forms a certain basic step coverage in the early stage of deposition. In the suppression step, a suppression gas is introduced into the reaction chamber. The suppression gas dissociates into high-energy ions under the action of plasma, forming a suppression region from top to bottom in the recessed structure. In the second deposition step, a second dielectric layer is deposited on the surface of the first dielectric layer after the suppression region is formed using a pulsed CVD process or an ALD process. Since the first dielectric layer forms a suppression region from top to bottom, the deposition rate at the top opening is reduced, and more gas molecules enter the depth of the recessed structure. The pulsed CVD process or the ALD process can compensate for the step coverage of the first dielectric layer, so that the final step coverage of the second dielectric layer is greater than or equal to 95%, achieving high conformal deposition with uniform sidewall thickness and good bottom coverage.

[0031] (2) After the first dielectric layer is formed in the first deposition step, an inert gas is introduced into the reaction chamber. Under the action of plasma, high-energy ions are formed. The high-energy ions bombard the first dielectric layer in the recessed structure to densify the loose first dielectric layer. Similarly, after the second dielectric layer is formed in the second deposition step, the second dielectric layer can be processed to improve the film quality of all dielectric layers in the recessed structure. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the step coverage of the film of the present invention.

[0033] Figure 2 This is a schematic flowchart of a dielectric thin film deposition process according to the present invention.

[0034] Figure 3 This is a partial structural diagram of the substrate obtained by CVD deposition according to the present invention.

[0035] Figure 4 This is a partial structural diagram of the substrate obtained by combining the suppression step and the ALD process according to the present invention.

[0036] Figure 5 This is a partial structural schematic diagram of the substrate obtained by the dielectric thin film deposition process of the present invention, and a partial enlarged view of the opening at the top of the recessed structure.

[0037] Figure 6 This is a schematic diagram of the chamber structure of a plasma processing device according to the present invention.

[0038] Attached Figure Labels 1-Gas spray head, 2-Heater, 3-Radio frequency rod. Detailed Implementation

[0039] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the dielectric thin film deposition process and plasma processing equipment proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0040] definition: Duty cycle of RF pulse: pulse high level duration ÷ pulse period × 100%.

[0041] Step coverage (SC) is a key indicator measuring the uniformity of thin film deposition on non-planar substrates (such as substrates with "step" structures like trenches, holes, and bumps). It directly determines the performance stability (such as insulation, conductivity, and dielectric properties) and yield of devices. Its calculation formula is: Step coverage = (film thickness at the bottom / sidewall of the step) ÷ (film thickness at the top of the step) × 100%.

[0042] like Figure 1 As shown, 'a' represents the film thickness of the bottom sidewall of the step (the sidewall where the bottom wall of the recessed structure is less than 10%), and 'b' represents the film thickness of the top of the step. The formula for calculating the step coverage rate is: a / b×100%. A step coverage rate close to 100% (usually ≥95%) indicates high conformability, meaning that the film thickness of the top and sidewalls of the step is almost the same.

[0043] Atomic layer deposition (ALD) is a thin film fabrication process based on surface-constrained chemical reactions. It involves alternating, pulsed introduction of two or more gaseous precursors, causing them to undergo layer-by-layer chemical adsorption and reaction on the substrate surface, ultimately forming a thin film with precisely controllable thickness. In the ALD process, the first precursor is introduced, and its molecules chemically adsorb onto active sites on the substrate surface until all sites are occupied (forming a monolayer). After purging to remove unreacted precursors, the second precursor is introduced, reacting chemically with the adsorbed precursor to similarly form a monolayer. This reaction automatically terminates once complete. This self-constrained reaction ensures that a uniform atomic layer is grown in each cycle, regardless of surface morphology, achieving a high step coverage.

[0044] However, the deposition rate of ALD (Atomic Layer Deposition) is relatively slow because the growth of each ALD layer involves introducing a precursor, allowing it to adsorb onto the substrate surface until saturation, then stopping the introduction of that precursor and purging, followed by introducing another precursor and purging again. This cycle generates only an extremely thin atomic layer, and the purging time often exceeds the reaction time. In practical applications, such as in the manufacturing of 3D-NAND flash memory chips, to achieve electrical connections between vertical layers and prevent leakage, deep contact holes (DCHs) penetrating multiple layers need to be etched first, and then dielectric materials with a thickness exceeding 200 nm are filled into the DCHs. Similarly, in the manufacturing of TSV (Through-Sinking Valves), a liner layer needs to be formed within the deep-hole structure. However, when using atomic layer deposition for such thick film filling, on the one hand, the deposition rate of atomic layer deposition is extremely slow; to obtain a thick film (e.g., 200 nm), hundreds or thousands of cycles need to be repeated, and the entire reaction takes at least several hours. On the other hand, in some high aspect ratio structures, the step coverage of the thick film is difficult to achieve the required 95% or higher.

[0045] Chemical vapor deposition (CVD) is a core thin-film manufacturing process in the semiconductor field. Essentially, it involves the chemical reaction of gaseous chemical reactants on a substrate surface to generate a solid thin film, which is then deposited onto the substrate. In CVD, on the one hand, increasing the flow rate and concentration of the reactant gases ensures a sufficient supply of reactants on the substrate surface, thereby increasing the reaction rate. On the other hand, heating provides energy to break the chemical bonds of the reactant gases, accelerating their "adsorption-decomposition-film formation" process on the substrate surface, further boosting the deposition rate. Therefore, CVD typically achieves high deposition rates.

[0046] However, chemical vapor deposition (CVD) struggles to achieve high step coverage. Firstly, due to the rapid deposition rate, most reactive gases are quickly consumed by the time they reach the top of the substrate's step structure (e.g., deep holes, trenches), leaving very little gas to diffuse to the sidewalls, especially the bottom. This results in a slow growth rate at the bottom, leading to an extremely thin film. Furthermore, if the step's aspect ratio is large (e.g., high aspect ratio trenches), the diffusion path becomes longer, potentially causing incomplete growth at the bottom due to insufficient reactants. Secondly, reactive gases are more easily adsorbed at the top of the step, resulting in a higher growth rate than at the sidewalls and bottom. The bottom may experience further reduced growth rates due to reactive gases being blocked by the step edges, leading to uneven growth across the step. Thirdly, chemical reactions produce gaseous byproducts that need to detach from the surface and diffuse away. In enclosed areas like the bottom of the step, these byproducts are difficult to expel, affecting the deposition rate. Therefore, the film formation process in CVD relies on "gas diffusion + surface reaction." When the reaction rate is much greater than the diffusion rate, a step coverage problem arises: rapid film formation at the top, but no film formation at the bottom.

[0047] It is evident that chemical vapor deposition (CVD) has a fast deposition rate but low step coverage, while atomic layer deposition (ALD) has a high step coverage but a slow deposition rate.

[0048] In summary, in practical applications of thick film deposition using atomic layer deposition (ALD) technology, achieving a step coverage of ≥100% and good film quality while maintaining a relatively fast deposition rate is a technical problem that urgently needs to be solved.

[0049] To address the aforementioned technical problems and achieve a balance between growth rate, step coverage, and film quality in the ALD process, this invention combines the high deposition rate advantage of chemical vapor deposition (CVD) and the high step coverage advantage of atomic layer deposition (ALD) to provide a dielectric film deposition process. This process includes a first deposition step, a suppression step, and a second deposition step. In the first deposition step, a first dielectric layer with a step coverage of ≥50% is deposited within a recessed structure using CVD. A suppression gas is then used to suppress the first dielectric layer, increasing the top opening and forming a suppression region from top to bottom within the recessed structure. In the second deposition step, a second dielectric layer with a second step coverage is deposited on the surface of the suppressed first dielectric layer using pulsed CVD or ALD. This second deposition step compensates for the step coverage of the first dielectric layer, increasing the second step coverage to over 100%. Furthermore, a modification step further modifies the first and / or second dielectric layers, improving the film quality.

[0050] like Figure 2 As shown, the present invention provides a dielectric thin film deposition process, comprising at least: Step S1: Provide a substrate with a recessed structure and place the substrate inside the reaction chamber.

[0051] The substrate may comprise one or more material layers, such as dielectric, conductive, or semiconductor material layers. The recessed structure may be either a high aspect ratio structure or a low aspect ratio structure. A high aspect ratio structure can be a recessed structure with an aspect ratio greater than or equal to 10:1. In some embodiments, the recessed structure may be a hole-like structure or a groove-like structure.

[0052] Step S2, First Deposition Step: Using a CVD process, a first dielectric layer with a first step coverage is deposited on the sidewalls and bottom of the recessed structure.

[0053] To improve the deposition rate and reduce time costs of the entire process, a first dielectric layer is first deposited on the sidewalls and bottom of the recessed structure using CVD. This can improve the deposition rate of the entire process and also form a dielectric film with a certain step coverage in the recessed structure. This makes it easier to compensate for the first dielectric layer with less than 100% step coverage in the subsequent process, so as to achieve the step coverage and film thickness required for practical applications.

[0054] Understandably, to reduce the difficulty of subsequent step coverage compensation, a high-rate deposition process, such as CVD, is needed at the beginning of deposition within the recessed structure to achieve a high step coverage. The lower the step coverage of the first dielectric layer, the more compensation is required, the longer the process time, and the higher the process difficulty. Therefore, the step coverage of the first dielectric layer needs to be greater than or equal to 50% to allow for compensation through subsequent processes. Similarly, if the step coverage of the first dielectric layer is less than 50%, almost no subsequent processes can compensate to achieve a 100% step coverage for the final dielectric film.

[0055] To further improve the step coverage of the first dielectric layer and significantly reduce the difficulty of subsequent step coverage compensation, the CVD process is a pulsed CVD process. For high aspect ratio recessed structures, the step coverage using conventional CVD processes can only reach a maximum of almost 50%, but with pulsed CVD, the step coverage can reach at least 70%. This is because the pulsed CVD process uses a "pulsed gas supply." In the first step, the precursor gas is introduced, allowing the reactant gas to diffuse fully within the recessed structure. At this point, without plasma or heat sources triggering the reaction, the precursor gas can penetrate undisturbed to the bottom of the recessed structure until the concentration of the precursor gas adsorbed on the entire surface of the recessed structure (top opening, sidewalls, and bottom) becomes uniform. The second step, activating the plasma source, triggers the reaction, causing the adsorbed precursor gas to decompose synchronously and form a thin film, thus avoiding the problem of low step coverage caused by "bottom precursor depletion."

[0056] It should be noted that the first dielectric layer deposited in the first deposition step of the present invention can be deposited using pulsed CVD process or other CVD processes that can deposit a step coverage of greater than or equal to 50%.

[0057] In some embodiments, in the first deposition step, a first dielectric layer is deposited using a pulsed CVD process, specifically including the following steps: Step S2.1: Introduce the first precursor gas and the second precursor gas into the reaction chamber, turn on the plasma source, and the first precursor gas and the second precursor gas react to generate the first dielectric layer.

[0058] Step S2.2: Turn off the plasma source and introduce inert gas into the reaction chamber for the first purging to terminate the deposition reaction and remove residual first precursor, second precursor and byproducts.

[0059] For shallow holes with a small aspect ratio (e.g., aspect ratio < 10:1), when forming the first dielectric layer using pulsed CVD, the duty cycle of the radio frequency pulse used should be 55-90% to ensure that the step coverage of the first dielectric layer is greater than or equal to 50%. For deep holes with a large aspect ratio (e.g., aspect ratio > 30:1), when forming the first dielectric layer using pulsed CVD, the duty cycle of the radio frequency pulse used should be 10-50% to ensure that the step coverage of the first dielectric layer is greater than or equal to 50%, allowing the reactant gas sufficient time (i.e., the plasma off phase) to diffuse into the bottom of the deep hole, and then react to form a dielectric film during the plasma on phase.

[0060] The pulsed CVD process includes a first frequency of 13.56 MHz or higher. Optionally, the first frequency is 40 MHz or 60 MHz. In some embodiments, to improve the deposition quality of the dielectric material at the bottom and depth of the deep hole, the process gas pressure of the pulsed CVD process is less than 10 torr. In other embodiments, the pulsed CVD process further includes a second frequency of 400 kHz or lower to further improve the deposition quality of the dielectric material within the deep hole.

[0061] In some embodiments, the first precursor gas comprises at least one of a metallic precursor gas, a non-metallic precursor gas, and a semiconductor precursor gas; the second precursor gas comprises at least one of an oxidizing gas, a reducing gas, and a nitrogen-containing gas; and the first dielectric layer formed by the reaction of the first and second precursor active particles is any one of a nitride, an oxide, and a nitrogen oxide. The thin film formed by this invention is a dielectric thin film, mainly used for electrical isolation, passivation protection, and other functions. Compared with ordinary thin films used for mechanical protection and optical coatings, dielectric thin films have more stringent requirements for the process. For example, the thickness of the dielectric layer directly affects the electrical performance of semiconductor devices (such as capacitance and breakdown voltage), requiring precise nanometer-level control. For micro / nano structures, high conformality is required (the thickness of the sidewalls and the top must be consistent), so ALD or high-quality CVD processes are commonly used to achieve this.

[0062] When the recessed structure has a high aspect ratio, poor film quality can occur when depositing the first dielectric layer using CVD technology. The main reasons are as follows: (1) During the process of the reactant gas entering the bottom of the concave structure through diffusion, it will preferentially react with the sidewall of the concave structure. A large amount of reactant gas is consumed near the top opening of the concave structure, which eventually leads to a significant decrease in the concentration of reactant gas reaching the bottom of the concave structure, forming a "concentration gradient from top to bottom". This "concentration gradient from top to bottom" makes the deposition rate at the bottom much lower than that at the top opening, eventually forming a loose film with "thin bottom and uneven sidewall".

[0063] (2) CVD reaction is accompanied by the generation of gaseous byproducts. In the recessed structure with a high aspect ratio, the gaseous byproducts are difficult to be discharged quickly. On the one hand, these gaseous byproducts may react with the film surface to generate unstable intermediate compounds. These intermediate compounds are trapped in the film and form impurities and defects. On the other hand, the space occupied by the gaseous byproducts will hinder the atomic arrangement of the reactant gas, resulting in micropores and gaps inside the film, which ultimately manifests as overall looseness and a decrease in mechanical and electrical properties.

[0064] To address the issue of poor film quality, the process of this invention further includes a modification step, namely, modifying the first dielectric layer deposited in the first deposition step: introducing a second processing gas into the reaction chamber, activating the plasma source, and modifying the first dielectric layer. In some embodiments, the second processing gas includes at least one of an inert gas and an oxidizing gas, a reducing gas, and a nitrogen-containing gas. Inert gas is excited into active particles under the action of plasma. These active particles bombard the first dielectric layer on the sidewalls of the recessed structure at high speed, transferring kinetic energy to the atoms of the newly deposited dielectric film. For the "loose atom pile" caused by insufficient reactant gas concentration and inadequate adsorption in the CVD process, the impact force of the high-energy active particles breaks the unstable weak bonds between atoms, forcing atoms to readjust their positions. This causes atoms with larger gaps to migrate to a lower-energy, closer-packed state, filling the micropores and gaps inside the first dielectric layer and increasing the density of the first dielectric layer. At the same time, when the high-energy active particles bombard the first dielectric layer, byproducts adsorbed on the surface of the first dielectric layer can be stripped and carried out of the recessed structure through "physical sputtering," thereby optimizing the chemical purity of the first dielectric layer and ultimately improving the quality of the film. To obtain better film quality, the modification step is performed after step S2.2, that is, after the first dielectric layer deposition is completed.

[0065] To overcome the physical and chemical limitations of single-pass deposition and ensure film quality and process stability during thick film deposition, a multi-step deposition method can be used to form the first dielectric layer. The advantages are: each deposition is a thinner layer, allowing for stress release between cycles; the purging step between multiple depositions reduces the impact of byproducts; and especially for high aspect ratio structures, step-by-step deposition allows for adjustment of the precursor / purging time in each step, improving conformability. Furthermore, this invention can modify the first dielectric layer after a single dielectric material deposition, or modify the multilayer first dielectric layer after multiple dielectric material depositions. In some embodiments, in the first deposition step, a 5nm single-layer first dielectric layer can be deposited using CVD, and after 10 cycles, a multilayer first dielectric layer with a thickness of 50nm can be deposited.

[0066] It is understandable that when the depth-to-width ratio of the recessed structure is high, the modification step can improve the film quality, making the film more similar to the film with higher density formed by the ALD process; when the depth-to-width ratio of the recessed structure is small, the sidewall film of the recessed structure has almost no porosity problem, so the modification step can be omitted to modify the sidewall film.

[0067] Step S3, Suppression step: A first processing gas is introduced into the reaction chamber to suppress at least a portion of the opening area of ​​the first medium layer. The first processing gas reacts with at least a portion of the material layer deposited on the sidewall of the recessed structure to form an suppression zone.

[0068] After forming a first dielectric layer with a step coverage of 50% or more, the first dielectric layer is subjected to a suppression treatment to form a suppression zone near the opening of the recessed structure on the first dielectric layer. The suppression zone is used to prolong the nucleation time of the second dielectric layer in this area during the subsequent deposition of the second dielectric layer, so that the second dielectric layer grows faster on the first dielectric layer in the non-suppression zone (i.e., deep and bottom of the recessed structure), which facilitates the subsequent deposition process to compensate for the first dielectric layer in order to achieve the step coverage required by the process.

[0069] The first processing gas contains at least one of a nitrogen-containing gas or a fluorine-containing gas, and the nitrogen-containing gas and the fluorine-containing gas form a suppression region from top to bottom within the recessed structure. The nitrogen-containing gas is selected from N2 and NH3, and the fluorine-containing gas is NF3. The first processing gas used varies depending on the aspect ratio of the recessed structure.

[0070] When the aspect ratio of the recessed structure is not particularly deep, using N2 and NH3 gases to suppress the deposition of the first dielectric layer can achieve better suppression effects. N2 and NH3 gases are excited into nitrogen-containing plasma under the action of plasma. This nitrogen-containing plasma annihilates charges through a conduit, forming nitrogen-containing free radicals. On one hand, the sidewalls of the recessed structure have high specific surface area, numerous surface defects, and dangling bonds, resulting in a large number of active sites. These active sites have a stronger adsorption capacity for reactive species. Nitrogen-containing free radicals, as electrically neutral but possessing unpaired electrons, are more easily and rapidly adsorbed onto these active sites through van der Waals forces and chemical bonds, weakening the surface adsorption of the recessed structure and thus inhibiting the deposition of subsequent dielectric layers.

[0071] When the depth-to-width ratio of the recessed structure is relatively deep, using NF3 gas to suppress the first dielectric layer can achieve a better suppression effect. Under the action of plasma, NF3 gas is excited into nitrogen / fluorine-containing plasma. The nitrogen / fluorine-containing plasma annihilates charges through a pipe, forming fluorine-containing free radicals and nitrogen-containing free radicals. The nitrogen-containing free radicals have an inhibitory effect, occupying at least some of the active sites of the first dielectric layer deposited on the sidewall of the recessed structure, forming surface bonds, thus delaying subsequent deposition. The fluorine-containing free radicals have an etching effect, reacting with the first dielectric layer to generate volatile substances, thus etching the first dielectric layer.

[0072] Step S4, second deposition step: using a first pulse CVD or ALD process, deposit a second dielectric layer with a second step coverage on the surface of the first dielectric layer after suppression treatment; wherein the second step coverage is greater than the first step coverage.

[0073] When suppressing a recessed structure to form a suppressed region, the cycle ratio of the suppression treatment to the second deposition step is crucial. If the suppression treatment time is too short, it may not be sufficient to fully form the suppressed region, and subsequent deposition may still result in a top "sealing," leading to poor film deposition quality at the bottom. If the suppression treatment time is too long, gas molecules may diffuse to the bottom of the recessed structure, hindering bottom deposition, compromising conformability, and preventing the second deposition step from compensating for the step coverage of the first deposition step. Therefore, in this invention, the cycle ratio of the suppression step to the second deposition step is 1:1 to 1:20 (1:1 means one suppression step and one ALD cycle; 1:20 means one suppression step and 20 ALD cycles) to achieve a balance between compensation and preventing premature closure of the opening.

[0074] Furthermore, due to the high deposition rate of CVD processes resulting in less dense films, and the slower deposition rate of ALD processes resulting in higher film quality, the duration of the first and second deposition steps can be selected according to actual process requirements. For example, if a pulsed CVD process is used to deposit the first dielectric layer, achieving a step coverage of 80%, then the subsequent ALD process depositing the second dielectric layer for compensation requires less compensation because the first deposition step has already achieved a high step coverage. Therefore, the duration of the ALD process is shorter, and in this case, the ratio of the durations of the first and second deposition steps might be 1:1. Alternatively, if a conventional CVD process is used to deposit the first dielectric layer, achieving a step coverage of approximately 50%, then the time and number of cycles required for subsequent ALD compensation will increase accordingly, reducing throughput. In this case, the ratio of the durations of the first and second deposition steps might be 1:9. However, due to the characteristics of the ALD process, the resulting film quality is also higher and denser.

[0075] In other applications, such as when a gap fill material is needed inside a recessed structure, such as... Figure 5As shown, to avoid premature closure of the opening and affect the subsequent filling effect, the present invention bombards the first dielectric layer after its formation to create a "gap" on the surface of the first dielectric layer, thus preventing premature closure of the opening and affecting the quality of the subsequently deposited film. In some embodiments, during the bombardment process, an inert gas can be simultaneously introduced into the reaction chamber by applying a first frequency and a second frequency. The first frequency is used to dissociate the inert gas to form cations, and the second frequency is used to increase the bombardment intensity of the cations to form a "gap" at the opening of the recessed structure.

[0076] It should be noted that the second dielectric layer deposited in the second deposition step of the present invention is not limited to pulsed CVD or ALD processes, but can also be other processes that can deposit a step coverage of greater than or equal to 95%, or processes that can compensate the step coverage of the first dielectric layer to greater than or equal to 95%, such as plasma-enhanced atomic layer deposition (PE-ALD) process.

[0077] Similarly, in order to solve the problem of poor quality of the second dielectric layer film, a modification step is also included, that is, to modify the second dielectric layer deposited in the second deposition step: a second processing gas is introduced into the reaction chamber, the plasma source is turned on, and the second dielectric layer is modified to improve the density of the second dielectric layer.

[0078] Example This embodiment provides a dielectric thin film deposition process as described in this invention, including: A substrate is provided, the substrate including a porous structure having a depth-to-width ratio of 10:1.

[0079] Step S1, First deposition step: Trichlorosilane, a silicon source gas, and ammonia, a nitrogen source gas, are introduced into the reaction chamber. Radio frequency is applied in the reaction chamber to excite the trichlorosilane and ammonia to form silicon-containing active particles and nitrogen-containing active particles. The silicon-containing active particles and nitrogen-containing active particles react to form a first silicon nitride dielectric layer on the sidewalls and bottom of the porous structure. Step S2: He is introduced into the reaction chamber for the first purging to remove residual reaction gases and byproducts in the reaction chamber; Step S3, Modification Step: Ar and O2 are introduced into the reaction chamber, and radio frequency is applied in the reaction chamber to excite and form plasma, while the inert gas Ar forms Ar. + Ions bombard the first silicon nitride dielectric layer to improve the density of the first silicon nitride dielectric layer and improve the film quality of the first silicon nitride dielectric layer; Step S4: He is introduced into the reaction chamber for a second purging to remove residual reaction gases and byproducts from the reaction chamber; Step S5, Suppression Step: Ar and NH3 are introduced into the reaction chamber. After the plasma source is turned on, under the action of the plasma, the introduced Ar and NH3 are excited to form Ar. + Ions and nitrogen-containing free radicals, Ar + Ions bombard the first silicon nitride dielectric layer at the top opening of the porous structure to increase the opening size. Nitrogen-containing free radicals occupy the active sites on the surface of the first silicon nitride dielectric layer, forming a top-to-bottom inhibition region. Step S6, second deposition step: Step S6.1: Transfer the substrate to the ALD reaction chamber, evacuate to the base pressure, and heat to the process temperature of 550°C; Step S6.2: Trichlorosilane, a silicon source gas, is introduced into the reaction chamber, and the silicon precursor covers the bottom and sidewalls of the porous structure by chemical adsorption. Step S6.3: Ar is introduced into the reaction chamber to remove unreacted silicon precursors and gaseous byproducts; Step S6.4: Nitrogen source gas ammonia is introduced into the reaction chamber. The nitrogen source reacts chemically with the silicon precursor to generate a second silicon nitride dielectric layer. Step S6.5: Ar is introduced into the reaction chamber again to remove residual nitrogen source gas and reaction byproducts.

[0080] In this embodiment, steps S1 to S4 are repeated 3 times. Of course, in other embodiments, the number of cycles can be adjusted according to the actual substrate structure, and the present invention is not limited thereto.

[0081] Through the above deposition, a silicon nitride dielectric layer with a total thickness of 100 nm is finally formed within the porous structure.

[0082] Correspondingly, such as Figure 6As shown, the present invention also provides a plasma processing device, comprising: a reaction chamber; a base located within the reaction chamber for supporting a substrate; a plasma source for exciting plasma formation; and a controller configured to perform the dielectric thin film deposition process as described above. The core function of the gas spray head 1 within the reaction chamber of the plasma processing device is to homogenize the gas, and it typically also serves as the upper electrode. The core function of the heater 2 within the reaction chamber is to heat the wafer to a precise process temperature and to support the wafer; it is mostly made of metal and grounded, and typically serves as the lower electrode. When an RF power supply is connected to at least one of the upper and lower electrodes, the other electrode is typically grounded. When the RF power supply is turned on, a high-intensity, high-speed alternating electric field is generated between the upper and lower electrodes. This electric field accelerates electrons within the reaction chamber, causing them to collide with gas molecules of the input reactive gas. These collisions lead to ionization of the reactive gas and excitation of the plasma, thereby generating plasma within the reaction chamber. It is understood that the RF can be fed from either the upper or lower electrode, and the other electrode can be directly grounded or used for RF tuning.

[0083] The plasma processing equipment includes plasma-enhanced chemical vapor deposition (PECVD) equipment, atomic layer (ALD) deposition equipment, plasma-enhanced atomic layer (PE-ALD) deposition equipment, etc.

[0084] In summary, the dielectric thin film deposition process provided by this invention involves, in the initial stage of deposition, using a high-rate CVD process to deposit a first dielectric layer with a step coverage of 50% within a recessed structure. This first dielectric layer undergoes a suppression treatment, forming a suppression region near the opening of the first dielectric layer within the recessed structure. This reduces the deposition rate of subsequent deposition gas at the top opening of the recessed structure, allowing the deposition gas to more easily penetrate deeper into the recessed structure. Then, using a first-pulse CVD process or ALD process with better conformality, a second dielectric layer is deposited on the surface of the first dielectric layer to compensate for the step coverage of the first dielectric layer, ensuring that the final step coverage of the dielectric layer within the recessed structure is at least 95%. Furthermore, the first and second dielectric layers are modified to densify the films, thereby improving the overall quality of the dielectric film.

[0085] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0086] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0087] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0088] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0089] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A dielectric thin film deposition process, characterized in that, At least includes: A substrate with a recessed structure is provided, and the substrate is placed inside a reaction chamber; First deposition step: Using a CVD process, a first dielectric layer with a first step coverage is deposited on the sidewalls and bottom of the recessed structure; Suppression step: A first processing gas is introduced into the reaction chamber to suppress at least a portion of the opening area of ​​the first medium layer. The first processing gas reacts with at least a portion of the material layer deposited on the sidewall of the recessed structure to form an suppression zone. Second deposition step: Using a first pulse CVD or ALD process, a second dielectric layer with a second step coverage is deposited on the surface of the first dielectric layer after the suppression treatment; The second step coverage rate is greater than the first step coverage rate.

2. The dielectric thin film deposition process as described in claim 1, characterized in that, In the first deposition step, the CVD process is a pulsed CVD process.

3. The dielectric thin film deposition process as described in claim 1, characterized in that, The step coverage of the first dielectric layer is greater than or equal to 50%.

4. The dielectric thin film deposition process as described in claim 2, characterized in that, The duty cycle of the radio frequency pulse in the pulsed CVD process is 55-90%.

5. The dielectric thin film deposition process as described in claim 2, characterized in that, The duty cycle of the radio frequency pulse in the pulsed CVD process is 10~50%.

6. The dielectric thin film deposition process as described in claim 5, characterized in that, The process gas pressure of the pulsed CVD process is less than 10 torr.

7. The dielectric thin film deposition process as described in claim 2, characterized in that, The pulsed CVD process includes a first frequency, which is greater than or equal to 13.56 MHz.

8. The dielectric thin film deposition process as described in claim 5, characterized in that, The pulsed CVD process also includes a second frequency, which is less than or equal to 400 kHz.

9. The dielectric thin film deposition process as described in claim 1, characterized in that, The step coverage of the second dielectric layer is greater than or equal to 95%.

10. The dielectric thin film deposition process as described in claim 1, characterized in that, It also includes a modification step: introducing a second processing gas into the reaction chamber, turning on the plasma source, exciting the second processing gas into active particles, and using the active particles to modify the first dielectric layer and / or the second dielectric layer to improve the film quality.

11. The dielectric thin film deposition process as described in claim 10, characterized in that, The second processing gas is selected from at least one of inert gases, oxidizing gases, reducing gases, and nitrogen-containing gases.

12. The dielectric thin film deposition process as described in claim 10, characterized in that, The modification step is performed after the first deposition step, and involves processing the first dielectric layer.

13. The dielectric thin film deposition process as described in claim 10, characterized in that, The dielectric thin film deposition process includes: Step S1: Deposit a first dielectric layer on the sidewalls and bottom of the recessed structure using CVD or pulsed CVD process; Step S2: A second processing gas is introduced into the reaction chamber to modify the first medium layer; Step S3: Introduce a first processing gas into the reaction chamber to suppress the first medium layer; Step S4: Deposit a second dielectric layer on the surface of the first dielectric layer after the suppression treatment using pulsed CVD or ALD process; The process involves repeating steps S1 to S2 N times, where N is an integer greater than 0.

14. The dielectric thin film deposition process as described in claim 10, characterized in that, The modification step is performed after the second deposition step, and the second dielectric layer is processed.

15. The dielectric thin film deposition process as described in claim 1, characterized in that, The first deposition step includes at least: introducing a first precursor gas and a second precursor gas into the reaction chamber, turning on the plasma source, and reacting the first precursor gas and the second precursor gas to generate the first dielectric layer.

16. The dielectric thin film deposition process as described in claim 15, characterized in that, The first precursor gas includes at least one of the following: metallic precursor gas, non-metallic precursor gas, and semiconductor precursor gas.

17. The dielectric thin film deposition process as described in claim 15, characterized in that, The second precursor gas contains at least one of an oxidizing gas, a reducing gas, and a nitrogen-containing gas.

18. The dielectric thin film deposition process as described in claim 1, characterized in that, In the suppression step, the first processing gas includes an inert gas and at least one of a nitrogen-containing gas and a fluorine-containing gas.

19. The dielectric thin film deposition process as described in claim 18, characterized in that, The first processing gas contains at least one gas selected from NF3, N2, and NH3.

20. The dielectric thin film deposition process as described in claim 1, characterized in that, The first dielectric layer and the second dielectric layer are any one of nitride, oxide, and oxynitride.

21. The dielectric thin film deposition process as described in claim 1, characterized in that, After the first dielectric layer is formed, the suppression step and the second deposition step are repeated in a cycle until a dielectric film of the target thickness is formed.

22. The dielectric thin film deposition process as described in claim 21, characterized in that, The cycle ratio of the inhibition step to the second deposition step is 1:1 to 1:

20.

23. The dielectric thin film deposition process as described in claim 21, characterized in that, The target thickness is greater than or equal to 100 nm.

24. A plasma processing device, characterized in that, include: reaction chamber; The base, located within the reaction chamber, is used to support the substrate; A plasma source, used to excite and form plasma; A controller configured to perform the dielectric thin film deposition process as described in any one of claims 1 to 23.

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