Semiconductor structure and preparation method thereof
By depositing the buffer layer, hard mask layer and anti-reflection layer in sequence on the semiconductor substrate, the same deposition process and the nitrogen content are controlled, the high cost and stress problems caused by different deposition processes in the semiconductor industry are solved, and more efficient Preparation and performance improvement.
Patent Information
- Application Number
- CN202310954480.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-31
- Publication Date
- 2025-02-14
AI Technical Summary
In the semiconductor industry, when deposition of isolation protective films and hard masks using different deposition processes, different equipment and processes are required, resulting in high preparation costs, and the stress problem of the hard mask layer leads to uneven surface of the film layer, which affects the impact of the impact of the impact of the impact of the stress problem of the hard mask layer. Device performance.
By depositing the buffer layer, the hard mask layer and the anti-reflection layer in sequence on the semiconductor substrate, the same deposition process (such as LPCVD) is used to prepare, and the nitrogen content in each film layer is adjusted by controlling the gas flow ratio, changing the The stresses of the film layer cancel each other out.
The equipment required to adopt different deposition processes is reduced, the preparation cost is reduced, and the performance of semiconductor devices and the flatness of the film layer is improved by adjusting the film layer stress.
Smart Images
Figure CN119451252A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a semiconductor structure and a method for preparing the same. Background Art
[0002] In the current semiconductor industry, when using silicon nitride as an isolation protective film and a hard mask, it is generally necessary to deposit a buffer layer using an atmospheric pressure chemical vapor deposition (APCVD) process under high temperature conditions; then a low pressure chemical vapor deposition (LPCVD) process is used to deposit a hard mask layer; and then a plasma enhanced chemical vapor deposition (PECVD) process is required to deposit an anti-reflective layer on the surface of the hard mask layer; when depositing different film layers, different deposition processes need to be used respectively, so different equipment needs to be used, and the preparation cost is relatively high. Summary of the invention
[0003] The semiconductor structure provided by the present application includes:
[0004] substrate;
[0005] a buffer layer located on the substrate;
[0006] a hard mask layer located on the buffer layer, wherein the nitrogen content of the hard mask layer is the nitrogen content of the standard stoichiometric ratio;
[0007] At least one anti-reflection layer is located on the hard mask layer, wherein the anti-reflection layer and the buffer layer contain the same constituent elements, and the content of nitrogen in at least one anti-reflection layer is the same as or different from the content of nitrogen in the buffer layer.
[0008] In some possible implementations, a plurality of anti-reflection layers are formed on the hard mask layer, and in a direction along the anti-reflection layer away from the substrate, the nitrogen content in the anti-reflection layer decreases layer by layer.
[0009] In some possible implementations, a plurality of anti-reflection layers are formed on the hard mask layer, and the thickness of the anti-reflection layers increases layer by layer in a direction along the anti-reflection layers away from the substrate.
[0010] In some possible implementations, the thickness of the hard mask layer is not less than the thickness of the buffer layer and not greater than the thickness of the anti-reflection layer.
[0011] In some possible implementations, the refractive index of the buffer layer and the anti-reflection layer is not greater than the refractive index of the hard mask layer.
[0012] In some possible implementations, the content of nitrogen in the anti-reflection layer is in the range of 0-40%.
[0013] The present application provides a method for preparing a semiconductor structure, comprising:
[0014] Providing a substrate, wherein the substrate is located in a reaction chamber;
[0015] Introducing a silicon-containing gas and a first nitrogen-containing gas into the reaction chamber, and depositing a buffer layer on the substrate using a first deposition process;
[0016] Introducing the silicon-containing gas and the second nitrogen-containing gas into the reaction chamber, and depositing a hard mask layer on the buffer layer using the first deposition process;
[0017] Introducing the silicon-containing gas and the third nitrogen-containing gas into the reaction chamber, and depositing at least one anti-reflection layer on the hard mask layer using the first deposition process;
[0018] The first nitrogen-containing gas, the second nitrogen-containing gas and the third nitrogen-containing gas all include at least a first reaction gas and a second reaction gas, and the composition ratios of the first reaction gas and the second reaction gas are different.
[0019] In some possible implementations, the preparation method further includes: before depositing the buffer layer, pre-treating the surface of the substrate using the second reaction gas.
[0020] In some possible implementations, among the first nitrogen-containing gas, the second nitrogen-containing gas, and the third nitrogen-containing gas, the proportion of the first reaction gas gradually decreases.
[0021] In some possible implementations, the film stress of the hard mask layer formed by the first deposition process is tensile stress, and the film stress of the buffer layer and the anti-reflection layer formed is compressive stress.
[0022] The present application uses a first deposition process to sequentially deposit a buffer layer, a hard mask layer, and an anti-reflection layer on a semiconductor substrate, that is, the buffer layer, the hard mask layer, and the anti-reflection layer are all prepared in the same machine using the same deposition process to reduce the equipment required for other deposition processes, thereby reducing costs. And by controlling the gas flow ratio introduced into the reaction chamber, the nitrogen content in each film layer material is controlled, thereby changing the stress of the corresponding film layer, so that the stress between each film layer offsets each other, reducing the impact of stress, and improving the performance of semiconductor devices. In addition, the difference in nitrogen atom content will also affect the light refractive index of the film. The top anti-reflection layer of the present application uses one or more layers of thin films with a lower refractive index. By adjusting the film thickness of the anti-reflection layer, more light waves enter the substrate, reducing its reflection, thereby improving the standing wave effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 A schematic diagram of a semiconductor structure provided in an embodiment of the present application;
[0024] Figure 2 A schematic diagram of another semiconductor structure provided in an embodiment of the present application;
[0025] Figure 3 A schematic diagram of another semiconductor structure provided in an embodiment of the present application;
[0026] Figure 4 A schematic diagram of another semiconductor structure provided in an embodiment of the present application;
[0027] Figure 5 A graph showing the content of nitrogen and the refractive index provided in an embodiment of the present application;
[0028] Figure 6 A flowchart of a semiconductor manufacturing method provided in an embodiment of the present application;
[0029] Figure 7 A graph showing the nitrogen content and film stress provided in an embodiment of the present application;
[0030] Figure 8 A schematic diagram of a stress provided in an embodiment of the present application;
[0031] Fig. 9 A schematic diagram of another stress provided in an embodiment of the present application. DETAILED DESCRIPTION
[0032] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be clearly and completely described below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. And in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Based on the described embodiments of the present application, all other embodiments obtained by ordinary technicians in the field without creative work belong to the scope of protection of this application.
[0033] Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. "First", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and other similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and other similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.
[0034] It should be noted that the sizes and shapes of the figures in the accompanying drawings do not reflect the actual proportions, but are only intended to illustrate the content of the present application. The same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions.
[0035] For example, Figure 1 As shown, in the prior art, a buffer layer 20 is generally deposited on the substrate 10 by atmospheric pressure chemical vapor deposition (APCVD) process under high temperature conditions. For example, Figure 2 As shown, a hard mask layer 30 is then deposited at a location away from the substrate 10 by a low pressure chemical vapor deposition (LPCVD) process under high temperature conditions. Figure 3As shown, the anti-reflection layer 40 is then deposited at the location of the hard mask layer 30 away from the substrate 10 using a plasma enhanced chemical vapor deposition (PECVD) process under high temperature conditions. Among them, the material of the buffer layer 20 is generally silicon dioxide (SiO2), the material of the hard mask layer 30 is generally silicon nitride (Si3N4), and the material of the anti-reflection layer 40 is generally silicon oxynitride (SiON). Among them, the buffer layer 20 has a buffering effect, which can buffer the stress of the hard mask layer 30 on the substrate 10. The anti-reflection layer 40 has an anti-reflection effect in the subsequent photolithography stage to reduce the standing wave effect.
[0036] It can be seen from the above that different deposition processes need to be used when depositing each film layer. Different deposition processes generally require different equipment and involve more processes and steps, so the fault tolerance is low and the production cost is high.
[0037] In addition, when the hard mask layer 30 is deposited, a layer of silicon nitride film is also deposited on the inner wall of the reaction chamber where the hard mask layer is deposited. Due to the stress problem of the silicon nitride film, the silicon nitride film is peeled off from the reaction chamber, and particles are generated. The particles make the surface of the deposited film layer uneven and not flat, thereby blocking the light in the subsequent photolithography process, and affecting the performance of the semiconductor device. Among them, the reaction chamber includes a furnace tube, that is, a layer of silicon nitride film is formed on the inner wall of the furnace tube, so the furnace tube needs to be cleaned and maintained regularly. As a result, the preventive maintenance cycle of the furnace tube is shortened and the maintenance cost is increased.
[0038] Based on the above problems, the present application provides a semiconductor structure, such as Figure 4 As shown, including:
[0039] Base 10;
[0040] a buffer layer 20 located on the substrate;
[0041] A hard mask layer 30 located on the buffer layer 20, wherein the nitrogen content of the hard mask layer 30 is the nitrogen content of the standard stoichiometric ratio;
[0042] At least one anti-reflection layer 40 is disposed on the hard mask layer 30 . The anti-reflection layer 40 and the buffer layer 20 include the same constituent elements. The nitrogen content in the at least one anti-reflection layer 40 is the same as or different from the nitrogen content in the buffer layer 20 .
[0043] The present application forms a buffer layer, a hard mask layer and an anti-reflection layer in sequence on a substrate, wherein the anti-reflection layer, the buffer layer and the hard mask layer contain the same constituent elements, and the nitrogen content in each film layer material can be controlled to thereby change the stress of the corresponding film layer, so that the stresses between each film layer offset each other, thereby reducing the impact of the stress and improving the performance of the semiconductor device.
[0044] For example, when an anti-reflective layer is deposited on the buffer layer, the nitrogen content of the buffer layer is the same as the nitrogen content of the anti-reflective layer, which may include 5%, 10%, 15%, 40%, etc., which is not limited here; of course, the nitrogen content of the buffer layer may also be different from the nitrogen content of the anti-reflective layer.
[0045] Exemplarily, when a plurality of anti-reflection layers are deposited on the buffer layer, the nitrogen content of the buffer layer is the same as the nitrogen content of one anti-reflection layer, two anti-reflection layers, three anti-reflection layers, etc. in the plurality of anti-reflection layers, for example, it may include 5%, 10%, 15%, 40%, etc., which is not limited here; of course, the nitrogen content of the buffer layer may also be different from the nitrogen content of one anti-reflection layer, two anti-reflection layers, three anti-reflection layers, etc. in the plurality of anti-reflection layers.
[0046] In some embodiments of the present application, multiple anti-reflection layers are formed on the hard mask layer, and the nitrogen content in the anti-reflection layers decreases layer by layer in a direction away from the substrate along the anti-reflection layers.
[0047] For example, Figure 4 As shown, the multilayer anti-reflection layer 40 includes: a first anti-reflection layer 401 and a second anti-reflection layer 402; wherein the nitrogen content of the first anti-reflection layer 401 is 40%, and the nitrogen content of the second anti-reflection layer 402 is 20%. Of course, there may also be three anti-reflection layers, four anti-reflection layers, etc., which are not limited here.
[0048] For example, if an anti-reflection layer is formed on the hard mask layer, the anti-reflection layer adopts a single-layer structure, and the nitrogen content in the anti-reflection layer can also gradually decrease from bottom to top in the single-layer structure of the anti-reflection layer. By adjusting the process parameters in the preparation process of the anti-reflection layer, it can be achieved that the nitrogen content in the single-layer anti-reflection layer gradually decreases in the direction away from the hard mask layer, and the nitrogen content on the lower surface of the anti-reflection layer is lower than the nitrogen content on the upper surface. In this embodiment, the nitrogen content of the anti-reflection layer varies in the range of 0-40%.
[0049] In some embodiments of the present application, multiple anti-reflection layers (such as 401 and 402 in the figure) are formed on the hard mask layer 30, and the thickness of the anti-reflection layers (such as 401 and 402 in the figure) increases layer by layer in the direction of the anti-reflection layer 40 away from the substrate 10.
[0050] In some embodiments of the present application, Figure 4 As shown, the thickness of the hard mask layer 30 is not less than the thickness of the buffer layer 20, and not greater than the thickness of the anti-reflection layer 40. Thus, by adjusting the thickness of each film layer, more light can enter the substrate, reducing light reflection, thereby improving the standing wave effect. Figure 4 The arrowed lines in the figure represent the incident path and the refraction path of the light. The thickness of each film layer can be set according to the requirements and is not limited here.
[0051] In some embodiments of the present application, the refractive index of the buffer layer 20 and the anti-reflection layer 40 is not greater than the refractive index of the hard mask layer 30 .
[0052] It should be noted that the content of nitrogen will also affect the refractive index of the film layer. The anti-reflection layer in the embodiment of the present application is a film layer with a lower refractive index. Figure 5 As shown, the refractive index R is positively correlated with the nitrogen content N, that is, the greater the nitrogen content N, the greater the refractive index R. For example, the refractive index can be adjusted by adjusting the nitrogen content of each film layer, so that more light enters the substrate, reducing reflection, thereby improving the standing wave effect.
[0053] In some embodiments of the present application, the content of nitrogen in the anti-reflection layer 40 is in the range of 0-40%.
[0054] For example, when an anti-reflection layer is deposited on the hard mask layer, the nitrogen content of the hard mask layer is different from the nitrogen content of the anti-reflection layer, for example, the nitrogen content of the hard mask layer is 40%, and the nitrogen content of the anti-reflection layer is 20%. When multiple anti-reflection layers are deposited on the hard mask layer, the nitrogen content of the hard mask layer is different from the nitrogen content of at least one of the multiple anti-reflection layers, for example, the nitrogen content of the hard mask layer is 40%, and the nitrogen content of at least one of the multiple anti-reflection layers is 20%.
[0055] The present application provides a method for preparing a semiconductor structure. Figure 6 As shown, including:
[0056] S11, providing a substrate, wherein the substrate is located in a reaction chamber;
[0057] S12, introducing a silicon-containing gas and a first nitrogen-containing gas into the reaction chamber, and depositing a buffer layer on the substrate using a first deposition process;
[0058] S13, introducing a silicon-containing gas and a second nitrogen-containing gas into the reaction chamber, and depositing a hard mask layer on the buffer layer using a first deposition process;
[0059] S14, introducing a silicon-containing gas and a third nitrogen-containing gas into the reaction chamber, and depositing at least one anti-reflection layer on the hard mask layer using a first deposition process;
[0060] The first nitrogen-containing gas, the second nitrogen-containing gas and the third nitrogen-containing gas all include at least a first reaction gas and a second reaction gas, and the composition ratios of the first reaction gas and the second reaction gas are different.
[0061] The present application uses a first deposition process to sequentially deposit a buffer layer, a hard mask layer, and an anti-reflection layer on a substrate, that is, the buffer layer, the hard mask layer, and the anti-reflection layer all use the same deposition process, which can reduce the equipment required for other deposition processes, thereby reducing costs. And by controlling the composition ratio of the first reaction gas and the second reaction gas introduced into the reaction chamber, the nitrogen content in each film layer material is controlled, thereby changing the stress of the corresponding film layer, so that the stress between each film layer offsets each other, reducing the impact of stress, and improving the performance of the semiconductor device.
[0062] Exemplarily, the first reaction gas includes ammonia gas; the second reaction gas includes nitrous oxide gas; the silicon-containing gas includes silane gas, dichlorosilane gas or trichlorosilane gas, etc.
[0063] In some embodiments of the present application, the preparation method further includes: before depositing the buffer layer, pre-treating the surface of the substrate using a second reaction gas.
[0064] The present application can passivate the defects on the substrate surface through pretreatment, reduce the lattice defects in the film layer during the subsequent deposition process, and thus affect the performance of the subsequent semiconductor device. Among them, the lattice defect is the area where the microscopic atomic arrangement of the material is affected by the crystal formation conditions, the thermal motion of atoms, impurity filling and other conditions, resulting in the structure deviating from the ideal crystal structure.
[0065] In some embodiments of the present application, the proportion of the first reaction gas in the first nitrogen-containing gas, the second nitrogen-containing gas, and the third nitrogen-containing gas gradually decreases.
[0066] In some embodiments of the present application, the film stress of the hard mask layer formed by the first deposition process is tensile stress, and the film stress of the buffer layer and the anti-reflection layer formed is compressive stress.
[0067] For example, Figure 7As shown, the nitrogen content N in each film layer is positively correlated with the stress S. That is, as the nitrogen content N increases, the stress S also gradually increases. Among them, the film stress includes tensile stress and compressive stress.
[0068] For example, Figure 8 As shown, the nitrogen content of the standard stoichiometric ratio of the hard mask layer 30 causes the film stress generated therein to be tensile stress, which means that the film shrinks faster relative to the substrate. Fig. 9 As shown, the nitrogen content of the buffer layer 20 and / or the anti-reflection layer 40 causes the film stress generated therein to be compressive stress, which means that the film shrinks slower than the substrate. It can be seen that compressive stress and tensile stress are opposite types to each other, and tensile stress and compressive stress offset each other, thereby reducing the stress problem of the film layer and the impact of stress.
[0069] It should be noted that, since the embodiment of the present application adopts the same deposition process, the film layers are deposited in the same reaction chamber, and multiple layers of thin films are deposited on the inner wall of the furnace tube in the reaction chamber. However, since the stress between the multiple layers of thin films can offset each other, the film layers will not peel off due to stress problems, and thus no particles will be generated, thereby improving the surface uniformity and flatness of the deposited film layers and improving the performance of semiconductor devices. Even if multiple layers of thin films are deposited on the inner wall of the furnace tube in the reaction chamber, it will not affect the subsequent processes, so the preventive maintenance cycle time of the furnace tube can be appropriately extended to reduce maintenance costs.
[0070] The following will be combined Figure 4 The semiconductor structure shown in the figure and Figure 6 The method flow chart shown in the figure further introduces the present application in detail.
[0071] During the pretreatment stage, the temperature in the reaction chamber is controlled to be maintained between 700°C and 900°C, and the pressure is maintained between 0.20 Torr and 0.50 Torr. Nitrous oxide (N2O) gas is introduced into the reaction chamber. The flow rate of the nitrous oxide (N2O) gas is controlled by a flow meter to be 100 sccm. The surface of the substrate 10 is pretreated, and the time required is approximately 1 minute.
[0072] Exemplarily, the material of the substrate includes: silicon, germanium or silicon-on-insulator (SOI), or other semiconductor materials known to those skilled in the art, which are not limited in the present application. In the embodiment of the present application, the material of the substrate 10 is silicon for illustration.
[0073] For example, the embodiment of the present application is described by maintaining the temperature in the reaction chamber between 700°C and 900°C. Of course, the temperature in the reaction chamber can also be maintained between 600°C and 1000°C, etc. The specific temperature in the reaction chamber can be set according to demand and is not limited here.
[0074] Illustratively, the embodiment of the present application is described by maintaining the pressure in the reaction chamber between 0.20 Torr and 0.50 Torr. Of course, the pressure in the reaction chamber can also be maintained between 0.10 Torr and 0.60 Torr, etc. The specific pressure in the reaction chamber can be set according to demand and is not limited here.
[0075] Illustratively, the flow rate of the reaction gas in the embodiments of the present application includes 100 sccm, 200 sccm, 300 sccm, etc. The flow rate of the reaction gas can be set according to demand and is not limited here.
[0076] In the first stage, the temperature in the reaction chamber is controlled to be maintained between 700°C and 900°C, and the pressure is maintained between 0.20 Torr and 0.50 Torr. Nitrous oxide (N2O) gas, ammonia (NH3) gas, and dichlorosilane (DCS) gas are introduced into the reaction chamber, and a buffer layer 20 is deposited on the substrate 10 using a first deposition process.
[0077] For example, the flow rate of dichlorosilane (DCS) gas is controlled by a flow meter to be 200 sccm, and the composition ratio of nitrous oxide (N2O) gas and ammonia (NH3) gas is controlled, wherein the proportion of nitrous oxide (N2O) gas is Keep R between 0 and 0.8.
[0078] It should be noted that the total amount of nitrous oxide (N2O) gas and ammonia (NH3) introduced is fixed, only the ratio of nitrous oxide (N2O) gas to ammonia (NH3) changes. For example, if more nitrous oxide (N2O) gas is introduced, less ammonia (NH3) will be introduced; if more ammonia (NH3) is introduced, less nitrous oxide (N2O) gas will be introduced.
[0079] For example, the material of the buffer layer 20 may include SiOxNy, wherein the content of nitrogen in the buffer layer 20 may be 20%. SiOxNy is a modified silicon nitride (Si3N4) material.
[0080] Exemplarily, the first deposition process may include: Low Pressure Chemical Vapor Deposition (LPCVD) process, Atomic Layer Deposition (ALD) process, Plasma Enhanced Chemical Vapor Deposition (PECVD) process, etc., which are not limited here.
[0081] In the second stage, the gas in the reaction chamber is extracted to reach a state where there is basically no gas remaining, in preparation for the third stage, ensuring that the process of the third stage will not be affected by the residual gas.
[0082] In the third stage, the temperature in the reaction chamber is controlled to be maintained between 700°C and 900°C, and the pressure is maintained between 0.20 Torr and 0.50 Torr. Ammonia (NH3) and dichlorosilane (DCS) gas are introduced into the reaction chamber, and the hard mask layer 30 is deposited at the buffer layer 20 away from the substrate 10 using the first deposition process.
[0083] Exemplarily, the flow rate of ammonia (NH 3 ) gas is 1600 sccm, and the flow rate of dichlorosilane (DCS) gas is 200 sccm.
[0084] Exemplarily, the material of the hard mask layer 30 may include silicon nitride (Si3N4), wherein the nitrogen content of the hard mask layer 30 is the nitrogen content of the standard stoichiometric ratio. The nitrogen content of the standard stoichiometric ratio represents the nitrogen content in silicon nitride (Si3N4) obtained by calculating the chemical composition of silicon nitride (Si3N4). Silicon nitride (Si3N4) is a material that conforms to the standard stoichiometric coefficient of the molecular formula.
[0085] In the fourth stage, the gas in the reaction chamber is extracted to reach a state where there is basically no gas remaining, in preparation for the fifth stage, ensuring that the process of the fifth stage will not be affected by the residual gas.
[0086] In the fifth stage, the temperature in the reaction chamber is controlled to be maintained between 700°C and 900°C, and the pressure is maintained between 0.20 Torr and 0.50 Torr. Nitrous oxide (N2O) gas, ammonia (NH3) gas, and dichlorosilane (DCS) gas with a second flow ratio are introduced into the reaction chamber. The first deposition process is used to deposit the first anti-reflection layer 401 at the location where the hard mask layer 30 is away from the substrate 10.
[0087] For example, the flow rate of dichlorosilane (DCS) gas is controlled by a flow meter to be 200 sccm, and the composition ratio of nitrous oxide (N2O) gas and ammonia (NH3) gas is controlled, wherein the proportion of nitrous oxide (N2O) gas is Keep R between 0.6 and 0.9.
[0088] Exemplarily, the material of the anti-reflection layer 401 may include: SiOxNy, wherein the nitrogen content in the first anti-reflection layer 401 is 40%. Wherein, SiOxNy is a modified silicon nitride (Si3N4) material.
[0089] In the sixth stage, the gas in the reaction chamber is extracted to reach a state where there is basically no gas remaining, in preparation for the seventh stage, ensuring that the process of the seventh stage will not be affected by the residual gas.
[0090] In the seventh stage, the temperature in the reaction chamber is controlled to be maintained between 700°C and 900°C, and the pressure is maintained between 0.20 Torr and 0.50 Torr. A second flow ratio of nitrous oxide (N2O) gas, ammonia (NH3) gas, and dichlorosilane (DCS) gas is introduced into the reaction chamber, and the second anti-reflection layer 402 is deposited at the position where the first anti-reflection layer 401 is away from the substrate 10 using the first deposition process.
[0091] For example, the flow rate of dichlorosilane (DCS) gas is controlled by a flow meter to be 200 sccm, and the composition ratio of nitrous oxide (N2O) gas and ammonia (NH3) gas is controlled, wherein the proportion of nitrous oxide (N2O) gas is Keep R between 0 and 0.6.
[0092] Exemplarily, the material of the second anti-reflection layer 402 may include: SiOxNy, wherein the content of nitrogen in the second anti-reflection layer 402 is 20%. Wherein, SiOxNy is a modified silicon nitride (Si3N4) material.
[0093] In the eighth stage, the gas in the reaction chamber is extracted to reach a state where there is basically no gas remaining, in preparation for the subsequent stages to ensure that the process in the subsequent stages will not be affected by the residual gas.
[0094] It can be known from the above stages that when depositing the film layer, the same deposition process is used, that is, it can be completed in the process step of the same equipment, and no other additional equipment is needed, which can reduce the cost. For example, the present application adopts LPCVD technology to concentrate the processes of multiple equipment into the process step of the same equipment. Among them, the hard mask layer is a silicon nitride layer of standard stoichiometry, and the buffer layer and the anti-reflection layer are modified silicon nitride. The preparation of the modified silicon nitride layer only needs to add an oxidizing gas pipeline to the original deposition pipeline. The deposition process only needs to regulate the content of nitrogen atoms in the film to achieve the preparation of different film layers. The preparation method of the present application does not increase the demand for equipment. In addition, the reaction chamber has a longer service life. The reaction chamber includes a furnace tube, that is, the furnace tube has a longer service life, which can reduce costs, and the preventive maintenance (Preventive Maintenance) cycle of the furnace tube is longer, which can reduce maintenance costs.
[0095] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.
[0096] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.
Claims
1. A semiconductor structure, characterized in that: include: substrate; a buffer layer located on the substrate; a hard mask layer located on the buffer layer, wherein the nitrogen content of the hard mask layer is the nitrogen content of the standard stoichiometric ratio; At least one anti-reflection layer is located on the hard mask layer, wherein the anti-reflection layer and the buffer layer contain the same constituent elements, and the content of nitrogen in at least one anti-reflection layer is the same as or different from the content of nitrogen in the buffer layer.
2. The semiconductor structure according to claim 1, wherein: A plurality of anti-reflection layers are formed on the hard mask layer, and the nitrogen content in the anti-reflection layers decreases layer by layer in a direction along the anti-reflection layers away from the substrate.
3. The semiconductor structure according to claim 1, wherein: A plurality of anti-reflection layers are formed on the hard mask layer, and the thickness of the anti-reflection layers increases layer by layer in a direction away from the substrate along the anti-reflection layers.
4. The semiconductor structure according to any one of claims 1 to 3, characterized in that: The thickness of the hard mask layer is not less than the thickness of the buffer layer and not greater than the thickness of the anti-reflection layer.
5. The semiconductor structure according to any one of claims 1 to 3, characterized in that: The optical refractive index of the buffer layer and the anti-reflection layer is not greater than the optical refractive index of the hard mask layer.
6. The semiconductor structure according to any one of claims 1 to 3, characterized in that: The content of nitrogen in the anti-reflection layer is in the range of 0-40%.
7. A method for preparing a semiconductor structure, characterized in that: include: Providing a substrate, wherein the substrate is located in a reaction chamber; Introducing a silicon-containing gas and a first nitrogen-containing gas into the reaction chamber, and depositing a buffer layer on the substrate using a first deposition process; Introducing the silicon-containing gas and the second nitrogen-containing gas into the reaction chamber, and depositing a hard mask layer on the buffer layer using the first deposition process; Introducing the silicon-containing gas and the third nitrogen-containing gas into the reaction chamber, and depositing at least one anti-reflection layer on the hard mask layer using the first deposition process; The first nitrogen-containing gas, the second nitrogen-containing gas and the third nitrogen-containing gas all include at least a first reaction gas and a second reaction gas, and the composition ratios of the first reaction gas and the second reaction gas are different.
8. The preparation method according to claim 7, characterized in that: The preparation method further includes: before depositing the buffer layer, pre-treating the surface of the substrate using the second reaction gas.
9. The preparation method according to claim 7, characterized in that: Among the first nitrogen-containing gas, the second nitrogen-containing gas, and the third nitrogen-containing gas, the proportion of the first reaction gas gradually decreases.
10. The preparation method according to any one of claims 7 to 9, characterized in that: The film stress of the hard mask layer formed by the first deposition process is tensile stress, and the film stress of the buffer layer and the anti-reflection layer formed is compressive stress.