Method for improving growth uniformity of silicon nitride film
By performing chemical pretreatment on wafer batches and employing low-pressure chemical vapor deposition, the problem of non-uniformity in silicon nitride film growth on furnace tube machines was solved, improving the thickness uniformity inside and outside the wafer, thereby enhancing product quality and production efficiency.
Patent Information
- Application Number
- CN202411085880.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-08
- Publication Date
- 2026-02-10
AI Technical Summary
When growing silicon nitride thin films on existing furnace tube machines, there are significant differences in the thickness of the silicon nitride thin films among wafers in different batches, which affects subsequent processes and increases the product defect rate. Existing methods for modifying the machine hardware are costly and time-consuming.
Selective chemical pretreatment is performed on a portion of the wafers in a wafer batch to introduce negatively charged groups, thereby improving the charge distribution on the wafer surface and enhancing the uniformity of the silicon nitride thin film. The silicon nitride thin film is grown using low-pressure chemical vapor deposition.
By making simple adjustments to the process steps, the uniformity of silicon nitride films inside and outside the wafer batch was improved, the furnace tube process yield and product performance were increased, and the improvement cost was reduced.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of integrated circuit manufacturing, and relates to a method for improving the uniformity of silicon nitride film growth. BACKGROUND
[0002] Silicon nitride film plays a crucial role in semiconductor devices, and the growth of silicon nitride film by a furnace tube machine is a conventional means. This method can complete the growth of silicon nitride film on the surfaces of dozens to hundreds of wafers at a time, and has low cost. However, due to the particularity of the structure of the furnace tube machine, please refer to Figure 1 , which shows a simplified structure diagram of a wafer batch in a furnace tube machine for performing silicon nitride film growth. The gas generally enters from the bottom of the furnace tube machine 20 (as shown by the dashed arrow in Figure 1 ), and is discharged from the top of the furnace tube machine 20 (as shown by the solid arrow in Figure 1 ). Therefore, there is a significant difference in the thickness of the silicon nitride film on the surfaces of the multiple wafers in the wafer batch 10 in the furnace tube machine 20 and different regions of each wafer surface. For example, please refer to Figure 2 , which shows an effect diagram of the thickness of the silicon nitride film grown on the surfaces of the wafers in the wafer batch changing with the height of the wafer. The thickness of the silicon nitride film 103 grown on the substrate 101 of the wafer at the bottom of the furnace tube machine 20 is relatively thick, and presents a morphology in which the thickness gradually decreases from the middle to the edge. The thickness of the silicon nitride film 103 grown on the substrate 101 of the wafer at the top of the furnace tube machine 20 is relatively thin, and presents a morphology in which the thickness gradually increases from the middle to the edge. The difference in the thickness and overall morphology of the silicon nitride film 103 grown on the wafers in the same wafer batch 10 will affect subsequent processes, for example, will bring challenges to subsequent CMP and Etch processes. In particular, in the case of a relatively thin silicon nitride film 103, it is easy to be etched through in the etching process, which makes it lose the role of the barrier layer, and further affects the product performance and yield.
[0003] In order to solve the above technical problems caused by the structure of the furnace tube machine, the existing technology usually modifies the hardware equipment of the machine, for example, modifies the shape, position and gas injector structure of the wafer boat that carries the wafers in the machine. However, the modification of the structure of the machine has high cost and long modification period, and cannot meet the immediate needs of the production line.
[0004] Therefore, how to provide a method for improving the uniformity of silicon nitride film growth to improve the uniformity of the growth of silicon nitride film by the wafer batch in the furnace tube device has become an important technical problem to be solved by the person skilled in the art.
[0005] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely describing the technical scheme of the present application and facilitating the understanding of the skilled in the art. The above technical scheme cannot be considered as known to the skilled in the art only because it is described in the technical background part of the present application. SUMMARY
[0006] In view of the above-mentioned defects of the prior art, the present application aims to provide a method for improving the uniformity of growth of a silicon nitride film, which is used to solve the problem that the uniformity of growth of a silicon nitride film by a furnace tube device needs to be improved in the prior art.
[0007] To achieve the above object and other related objects, the present application provides a method for improving the uniformity of growth of a silicon nitride film, which comprises the following steps:
[0008] providing a wafer batch, wherein the wafer batch comprises a plurality of wafers;
[0009] chemically pre-treating a preset wafer in the wafer batch to introduce negative charge groups to a pre-treatment area on the upper surface of the preset wafer;
[0010] placing the wafer batch in a furnace tube device to form a silicon nitride film on the upper surface of each wafer in the wafer batch, wherein the silicon nitride film covers the upper surface of the wafer.
[0011] Optionally, the treating agent used for the chemical pre-treatment of the preset wafer in the wafer batch comprises at least one of a piranha solution and a mixed solution of NH4OH and H2O2.
[0012] Optionally, the chemical pre-treatment of the preset wafer in the wafer batch is performed by keeping the preset wafer stationary and moving the supply source of the treating agent, or by keeping the supply source of the treating agent stationary and moving the preset wafer.
[0013] Optionally, the method further comprises the steps of selecting the preset wafer from the wafer batch and selecting a pre-treatment area of the preset wafer before the chemical pre-treatment of the preset wafer in the wafer batch.
[0014] Optionally, the selection of the preset wafer from the wafer batch and the selection of the pre-treatment area of the preset wafer are both based on the position of the preset wafer in the furnace tube device.
[0015] Optionally, according to the position distribution of each wafer in the wafer batch when placed in the furnace tube device, the wafer batch is divided into a first wafer group located at the upper portion of the furnace tube device, a second wafer group located at the middle portion of the furnace tube device, and a third wafer group located at the lower portion of the furnace tube device, the first wafer group includes at least one first wafer, the second wafer group includes a plurality of second wafers, and the third wafer group includes at least one third wafer, and the preset wafer includes at least one of the first wafer and the third wafer.
[0016] Optionally, the pre-treatment area of the first wafer includes a central area of the first wafer, and the pre-treatment area of the third wafer includes an edge area of the third wafer.
[0017] Optionally, when the first wafer group includes a plurality of first wafers, in the first wafer group, as the height of the first wafer increases, the pre-treatment area of the first wafer gradually expands from the central area to the edge area.
[0018] Optionally, when the third wafer group includes a plurality of third wafers, in the third wafer group, as the height of the third wafer decreases, the pre-treatment area of the third wafer gradually expands from the edge area to the central area.
[0019] Optionally, the method for forming a silicon nitride film includes a low-pressure chemical vapor deposition method, and the gas source used to form the silicon nitride film includes dichlorosilane and ammonia.
[0020] As described above, the method for improving the uniformity of the growth of a silicon nitride film of the present application effectively improves the uniformity of the growth of a silicon nitride film of the entire wafer batch by selectively performing chemical pre-treatment on part of the wafer batch before growing a silicon nitride film on the surface of the wafer batch placed in the furnace tube device, thereby improving the yield of the furnace tube process and the performance of the product. Moreover, the improvement method only needs to make a simple adjustment of the process steps without changing the furnace tube device and performing feasibility verification, so it is low in cost and easy to implement. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 A simplified structure diagram showing the wafer batch placed in the furnace tube device to perform silicon nitride film growth.
[0022] Figure 2 An effect diagram showing the thickness of the silicon nitride film grown on the surface of each wafer in the wafer batch changing with the height of the wafer.
[0023] Figure 3 A flowchart showing the steps of the method for improving the uniformity of the growth of a silicon nitride film of the present application.
[0024] Figure 4A simplified schematic diagram showing the wafer batch being placed in the furnace tube device in the method for improving the uniformity of growth of the silicon nitride film of the present application.
[0025] Figure 5 A distribution trend diagram showing the variation of the pretreatment area of each first wafer in the first wafer group with height in the method for improving the uniformity of growth of the silicon nitride film of the present application.
[0026] Figure 6 A distribution trend diagram showing the variation of the pretreatment area of each third wafer in the third wafer group with height in the method for improving the uniformity of growth of the silicon nitride film of the present application.
[0027] Figure 7 A cross-sectional schematic diagram of the wafer in the method for improving the uniformity of growth of the silicon nitride film of the present application.
[0028] Figure 8 A DCS adsorption effect schematic diagram showing the initial stage of growth of the silicon nitride film when the preset wafer is not chemically pretreated.
[0029] Figure 9 A cross-sectional schematic diagram of the structure obtained after the silicon nitride film is grown on the wafer surface when the preset wafer is not chemically pretreated.
[0030] Figure 10 A surface charge distribution schematic diagram of the preset wafer after it is chemically pretreated in the method for improving the uniformity of growth of the silicon nitride film of the present application.
[0031] Figure 11 A DCS adsorption effect schematic diagram showing the initial stage of growth of the silicon nitride film after the preset wafer is chemically pretreated in the method for improving the uniformity of growth of the silicon nitride film of the present application.
[0032] Figure 12 A cross-sectional schematic diagram of the structure obtained after the silicon nitride film is grown on the wafer surface in the method for improving the uniformity of growth of the silicon nitride film of the present application.
[0033] Figure 13 A first method for chemically pretreating the preset wafer in the method for improving the uniformity of growth of the silicon nitride film of the present application.
[0034] Figure 14 A second method for chemically pretreating the preset wafer in the method for improving the uniformity of growth of the silicon nitride film of the present application.
[0035] BRIEF DESCRIPTION OF THE DRAWINGS
[0036] 10 wafer batch
[0037] 11 first wafer group
[0038] 111 first wafer
[0039] 111a pre-processing area of the first wafer
[0040] 12 second wafer group
[0041] 121 second wafer
[0042] 13 third wafer group
[0043] 131 third wafer
[0044] 131a pre-processing area of the third wafer
[0045] 101 substrate
[0046] 102 oxide layer
[0047] 103 silicon nitride film
[0048] 20 furnace tube device
[0049] 30 boat
[0050] 40 supply source
[0051] S1-S3 steps DETAILED DESCRIPTION
[0052] The present application is herein described, by way of example only, with reference to embodiments thereof. It is to be understood that variations and modifications will be apparent to those skilled in the art and that the scope of the application encompasses all such variations and modifications as fall within the spirit and scope of the application. Therefore, the application should not be limited to the embodiments described herein but should be given the full scope defined by the language of the claims.
[0053] Reference is made to Figures 3 to 14 . It is to be understood that the drawings provided in this embodiment are merely schematic and that, for the purpose of presentation, they are simplified and only those parts of the application which are necessary for the understanding of the application as claimed are shown and therefore they should not be considered as limiting the scope of the application. The division of the elements into groups or categories should not be considered as limiting the scope of the application. In the drawings, like numbers refer to like elements throughout.
[0054] This embodiment provides a method for improving the uniformity of silicon nitride film growth. Referring to Figure 3 , a flow chart of the steps of the method is shown, which comprises the following steps:
[0055] S1: providing a wafer batch, the wafer batch comprising a plurality of wafers;
[0056] S2: performing chemical pretreatment on preset wafers in the wafer batch to introduce negative charge groups on the pretreatment area of the upper surface of the preset wafers;
[0057] S3: placing the wafer batch in a furnace tube device to form a silicon nitride film on the upper surface of each wafer in the wafer batch, the silicon nitride film covering the upper surface of the wafer.
[0058] First, referring to Figure 4 , step S1 is performed to provide a wafer batch 10 including a plurality of wafers, as shown in Figure 7 , the wafers include a substrate 101 (for example, a silicon substrate), and in the present embodiment, the wafers also include an oxide layer 102 formed on the substrate 101 (that is, the first wafer 111, the second wafer 121, and the third wafer 131 in the present embodiment all include the substrate 101 and the oxide layer 102), while in other embodiments, the wafers can only include the substrate 101, that is, the improvement method of the present embodiment is also applicable to the improvement of the uniformity of the thickness of the silicon nitride film grown on the surface of the bare substrate or the oxide layer above the substrate.
[0059] Further, referring to Figures 4 to 6 , step S2 is performed to perform chemical pretreatment on preset wafers in the wafer batch 10 to introduce negative charge groups (for example, hydroxyl groups) on the pretreatment area of the upper surface of the preset wafers.
[0060] As an example, before performing chemical pretreatment on the preset wafers in the wafer batch 10, the steps of selecting the preset wafers from the wafer batch 10 and selecting the pretreatment area of the preset wafers are also included.
[0061] Further, the selection of the preset wafers from the wafer batch 10 and the selection of the pretreatment area of the preset wafers are both based on the position of the preset wafers in the furnace tube device 20. Since there are corresponding calculation rules for the order and placement position of each wafer in the wafer batch 10 entering the furnace tube, for example, from small to large or from large to small according to the wafer ID, the system can set the corresponding rules and calculate the order or position of the wafers in advance according to the rules, so that the placement position of each wafer in the furnace tube device 20 can be determined before the wafer batch 10 enters the furnace tube device 20, and accordingly, the wafers that need to be chemically pretreated (that is, the preset wafers) and the position and size of the area that needs to be chemically pretreated (that is, the pretreatment area) of the preset wafers are obtained.
[0062] As an example, as shown in Figure 4As shown, according to the position distribution of each wafer when the wafer batch 10 is placed in the furnace tube device 20, the wafer batch 10 is divided into a first wafer group 11 located at the upper part of the furnace tube device 20, a second wafer group 12 located at the middle part of the furnace tube device 20, and a third wafer group 13 located at the lower part of the furnace tube device 20. The first wafer group 11 includes at least one first wafer 111, the second wafer group 12 includes a plurality of second wafers 121, and the third wafer group 13 includes at least one third wafer 131. The preset wafer includes at least one of the first wafer 111 and the third wafer 131. In this embodiment, both the first wafer 111 and the third wafer 131 are preset wafers. In other embodiments, only the first wafer 111 or only the third wafer 131 can be used as a preset wafer, which is selected according to actual process needs.
[0063] In a specific example, the first wafer group 11 includes 1-10 first wafers 111, and the third wafer group 13 includes 1-10 second wafers 121. In practice, the number of wafers included in the first wafer group 11 and the third wafer group 13 is selected according to actual needs. For example, according to historical production records of the furnace tube device 20, the number of wafers with obvious thickness differences located at the upper or lower part of the furnace tube device 20 under normal circumstances is understood to make specific division of the first wafer group 11 and the third wafer group 13. For wafers with slight thickness differences of silicon nitride thin film 103 or thickness differences that have an impact on subsequent processes within the process error tolerance, chemical pretreatment is not performed, thereby ensuring that the impact of the additional setting of the chemical pretreatment step on the overall production efficiency is controllable.
[0064] As an example, please refer to Figure 5 , which shows a distribution trend graph of the pretreatment area of each first wafer in the first wafer group with respect to height. The pretreatment area 111a of the first wafer includes the central area of the first wafer 111. Please refer to Figure 6 , which shows a distribution trend graph of the pretreatment area of each third wafer in the third wafer group with respect to height. The pretreatment area 131a of the third wafer includes the edge area of the third wafer 131.
[0065] As an example, as shown in Figure 5 , the direction of the arrow in Figure 5 indicates that the height of the first wafer 111 gradually increases. When the first wafer group 11 includes a plurality of first wafers 111, in the first wafer group 11, as the height of the first wafer 111 increases, the pretreatment area 111a of the first wafer gradually expands from the central area to the edge area. For example, for the uppermost first wafer 111, the pretreatment area may include the entire upper surface.
[0066] As an example, such as Figure 6 As shown, Figure 6 The direction indicated by the middle arrow is the direction in which the height of the third wafer 131 gradually decreases. When the third wafer group 13 includes multiple third wafers 131, within the third wafer group 13, as the height of the third wafer 131 decreases, the preprocessing region 131a of the third wafer gradually expands from the edge region to the central region. The extent to which the preprocessing regions of two adjacent first / third wafers extend is designed based on actual needs and is not specifically limited here.
[0067] As an example, the pretreatment agent used for chemical pretreatment of the preset wafers in the wafer batch 10 includes at least one of piranha solution (including H2SO4 and H2O2) and a mixed solution of NH4OH and H2O2. In this embodiment, the pretreatment agent is a mixed solution of NH4OH and H2O2. Since SC1, a commonly used cleaning agent in semiconductor manufacturing, includes the above-mentioned chemical components, it is relatively more convenient to use. Of course, in other embodiments, piranha solution or other suitable solutions that can introduce negatively charged groups on the wafer surface can also be used for chemical pretreatment. When using a mixed solution of NH4OH and H2O2, the OH groups in NH4OH are utilized... - This allows negative charges to accumulate on the wafer surface, while H2O2 is used to enhance oxidizing power and provide more OH groups. - In order to enhance the effectiveness of chemical pretreatment.
[0068] For example Figure 4 As shown, in step S3, the wafer batch 10 is placed in the furnace tube equipment 20 to form a silicon nitride film 103 on the upper surface of each wafer in the wafer batch 10, the silicon nitride film 103 covering the upper surface of the wafer. For example, each wafer in the wafer batch 10 is transferred to the crystal boat 30 of the furnace tube equipment 20 according to a predetermined rule to fix the wafers.
[0069] Specifically, after analyzing the problem of the difference in the uniformity of the thickness of the silicon nitride film caused by the different heights of the wafer in the furnace tube device mentioned in the background art, it is found that this non-uniformity may be caused by multiple factors, such as the difference in the gas flow rate, the pressure and temperature distribution in the furnace tube, etc. After analyzing the growth process of silicon nitride, it is found that when growing a silicon nitride film on the surface of a wafer, dichlorosilane (SiH2Cl2, referred to as DCS) is usually used as the silicon source and ammonia (NH3) is used as the nitrogen source. DCS, as a precursor, is first adsorbed on the growth substrate (i.e. the wafer), and then NH3 reacts with it to form a silicon nitride nucleus. Subsequently, the silicon nitride film is gradually expanded based on the silicon nitride nucleus as the growth core in the growth process. In the nucleation process, the adsorption behavior of DCS mainly relies on the breaking of the -Cl bond, so that the formed SiH2Cl is adsorbed on the surface of the wafer as an electron acceptor. When the wafer is placed at different heights in the furnace tube device, due to the differences in the above factors, the amount of DCS adsorbed on the surface of the wafer at different heights and on different regions of a single wafer surface will also be different. This difference will further cause the thickness profile difference as shown in Figure 2 Based on this, in the present application, the pre-set wafer in the wafer batch is chemically pretreated to introduce negative charge groups on the pre-set regions (regions with greater thickness deviation in the conventional growth process) on its upper surface, so that DCS is more easily adsorbed on the surface of the pre-set regions. That is, by changing the charge distribution on the wafer surface to improve the adsorption uniformity of DCS, the adverse effects caused by the different heights of the wafer on the uniformity of DCS adsorption are compensated for, thereby improving the thickness uniformity between wafers and within a wafer.
[0070] Further, reference can be made to Figures 7 to 12 for understanding. It is exemplarily illustrated whether the first wafer located at the upper part of the furnace tube device in the wafer batch is chemically pretreated before the growth of the silicon nitride film, wherein, Figure 7 shows a cross-sectional view of the first wafer to be grown with a silicon nitride film, Figure 8 shows a schematic diagram of the DCS adsorption effect at the initial stage of the growth of the silicon nitride film when the first wafer is not chemically pretreated, Figure 9 shows a cross-sectional schematic diagram of the structure obtained after the growth of the silicon nitride film on the surface of the first wafer without chemical pretreatment. At the initial stage of the growth of the silicon nitride film on the first wafer placed in the furnace tube device without chemical pretreatment on the surface of the first wafer, the adsorption of DCS on the edge region of the first wafer is obviously more than that on the central region. Due to the different adsorption degrees of DCS on different regions within the first wafer, the thickness of the silicon nitride film obtained after the growth is greater on the edge region of the first wafer than on the central region, and the overall thickness gradually increases from the center to the edge. Figure 10A schematic diagram showing the surface charge distribution of the first wafer after chemical pretreatment, Figure 11 A schematic diagram showing the DCS adsorption effect in the initial stage of silicon nitride film growth after chemical pretreatment of the first wafer, Figure 12 A schematic diagram showing the cross-section of the structure obtained after growing silicon nitride film on the surface of the first wafer after chemical pretreatment. Due to the effect of chemical pretreatment, the surface of the first wafer is uniformly distributed with negative charge groups. When the first wafer after chemical pretreatment is placed in the furnace tube device to grow silicon nitride film, the DCS precursor reacts with the negative charge groups to achieve uniform adsorption and further nucleation. On this basis, the silicon nitride film obtained by extension growth is basically uniformly distributed on the first wafer, and the thickness of the silicon nitride film in the wafer is relatively uniform. In addition, the change in the surface charge distribution of the wafer can further shorten the nucleation time and improve the growth rate of the silicon nitride film.
[0071] As an example, the way of chemical pretreatment of the preset wafer in the wafer batch 10 includes keeping the preset wafer stationary and moving the supply source 40 of the treatment agent to perform the chemical pretreatment (as shown in Figure 13 Alternatively, keeping the supply source 40 of the treatment agent stationary and moving the preset wafer to perform the chemical pretreatment (as shown in Figure 14
[0072] As an example, the method of forming the silicon nitride film 103 includes low-pressure chemical vapor deposition. The gas source used to form the silicon nitride film 103 includes dichlorosilane (DCS) and ammonia. Due to the different nucleation and reaction mechanisms when growing silicon nitride film by different methods, it has been verified through actual tests that this method is particularly suitable for improving the uniformity of silicon nitride film grown by LPCVD in the furnace tube device.
[0073] The method for improving the uniformity of silicon nitride film growth in the present embodiment selectively pretreats part of the wafers in the wafer batch before growing silicon nitride film on the surface of the wafer batch in the furnace tube device, and selects the pretreatment area of the wafer, thereby effectively improving the uniformity of silicon nitride film between wafers and within wafers in the wafer batch. The uniformity of silicon nitride film between wafers is achieved based on the selection of the preset wafer, and the uniformity of silicon nitride film within the wafer is achieved based on the selection of the pretreatment area in the preset wafer. This effectively improves the uniformity of silicon nitride film growth in the entire wafer batch, improves the furnace tube process yield and product performance. Moreover, the improvement method only needs to make simple adjustments to the process steps without changing the furnace tube device and performing feasibility verification, which is low in cost and easy to implement.
[0074] In summary, the method for improving the uniformity of the growth of the silicon nitride film of the present application, by selectively performing chemical pretreatment on part of the wafers in the wafer batch before growing the silicon nitride film on the wafer surface in the furnace tube equipment, effectively improves the uniformity of the growth of the silicon nitride film of the whole wafer batch, improves the furnace tube process yield and product performance. And the improvement method only needs to make a simple adjustment of the process steps, without changing the furnace tube equipment and feasibility verification, which is low in cost and easy to implement. Therefore, the present application effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.
[0075] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed by the present application should be covered by the claims of the present application.
Claims
1. A method for improving the uniformity of silicon nitride thin film growth, characterized in that, Includes the following steps: Provide a wafer batch, the wafer batch comprising a plurality of wafers; A predetermined wafer in the wafer batch is chemically pretreated to introduce negatively charged groups into the pretreated area on the upper surface of the predetermined wafer; The wafer batch is placed in a furnace tube apparatus to form a silicon nitride film on the upper surface of each wafer in the wafer batch, the silicon nitride film covering the upper surface of the wafer.
2. The method for improving the uniformity of silicon nitride thin film growth according to claim 1, characterized in that: The chemical pretreatment agents used for the pre-selected wafers in the wafer batch include at least one of piranha solution and a mixed solution of NH4OH and H2O2.
3. The method for improving the uniformity of silicon nitride thin film growth according to claim 2, characterized in that: The method of performing chemical pretreatment on a preset wafer in the wafer batch includes keeping the preset wafer stationary while moving the supply source of the processing agent to perform the chemical pretreatment, or keeping the supply source of the processing agent stationary while moving the preset wafer to perform the chemical pretreatment.
4. The method for improving the uniformity of silicon nitride thin film growth according to claim 1, characterized in that: Before performing chemical pretreatment on the preset wafers in the wafer batch, the process further includes the steps of selecting the preset wafers from the wafer batch and selecting the pretreatment area of the preset wafers.
5. The method for improving the uniformity of silicon nitride thin film growth according to claim 4, characterized in that: The selection of the preset wafer from the wafer batch and the selection of the preprocessing area for the preset wafer are both based on the position of the preset wafer in the furnace tube equipment.
6. The method for improving the uniformity of silicon nitride thin film growth according to claim 5, characterized in that: Based on the positional distribution of each wafer when the wafer batch is placed in the furnace tube equipment, the wafer batch is divided into a first wafer group located at the upper part of the furnace tube equipment, a second wafer group located in the middle part of the furnace tube equipment, and a third wafer group located at the lower part of the furnace tube equipment. The first wafer group includes at least one first wafer, the second wafer group includes multiple second wafers, and the third wafer group includes at least one third wafer. The preset wafer includes at least one of the first wafer and the third wafer.
7. The method for improving the uniformity of silicon nitride thin film growth according to claim 6, characterized in that: The preprocessing area of the first wafer includes the central region of the first wafer, and the preprocessing area of the third wafer includes the edge region of the third wafer.
8. The method for improving the uniformity of silicon nitride thin film growth according to claim 6, characterized in that: When the first wafer group includes multiple first wafers, in the first wafer group, as the height of the first wafer increases, the preprocessing area of the first wafer gradually expands from the central area to the edge area.
9. The method for improving the uniformity of silicon nitride thin film growth according to claim 6, characterized in that: When the third wafer group includes multiple third wafers, in the third wafer group, as the height of the third wafer decreases, the preprocessing area of the third wafer gradually expands from the edge area to the central area.
10. The method for improving the uniformity of silicon nitride thin film growth according to claim 1, characterized in that: Methods for forming silicon nitride thin films include low-pressure chemical vapor deposition, and the gas sources used to form the silicon nitride thin films include dichlorosilane and ammonia.