Crystal boats, batch processing equipment and low-pressure vapor deposition methods

Abstract

This application provides a wafer boat, a batch processing apparatus, and a low-pressure vapor deposition method. The wafer boat is used to deposit a product film layer on the front side of a product wafer, including adjacent first and second regions. The first region includes multiple product wafer trenches, and the second region includes a monitoring wafer trench. The second region is located on the support side of the product wafer trenches. The product wafer trenches support the product wafers and expose their back sides, with a first spacing between them. The monitoring wafer trenches support monitoring wafers and expose their back sides, with a second spacing between the first and second regions. The ratio of the first spacing to the second spacing is positively correlated with the ratio of the thermal emissivity of the film layer on the back side of the product wafers to the film layer on the back side of the monitoring wafers. This application can improve the uniformity of the product film layer thickness between product wafers at different locations on the wafer boat.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically to a crystal boat, a batch processing apparatus, and a low-pressure vapor deposition method. Background Technology

[0002] Semiconductor chips are typically manufactured from wafers through multiple processes. In the semiconductor chip manufacturing process, the furnace tube is an indispensable piece of equipment, used for processes such as deposition, diffusion, oxidation, and annealing on the wafer. Among these processes, the formation of different types of thin films on wafers using furnace tubes is a fundamental semiconductor chip manufacturing process. In this process, multiple product wafers (wafers used for production processing, the finished products are sold to customers) are first placed on a wafer boat, and then the wafer boat is placed inside the furnace tube.

[0003] In existing technologies, a wafer boat typically has a first region and a second region. The first region includes multiple product wafer slots for carrying product wafers, and the second region includes monitoring wafer slots for carrying monitoring wafers (wafers used for testing and monitoring the process status of product wafers, such as deposition or etching rates, film uniformity, particle contamination, etc.). The slot spacing within the wafer boat is typically uniform; that is, the spacing between adjacent product wafer slots is usually consistent with the spacing between adjacent product wafer slots and monitoring wafer slots.

[0004] However, when a wafer boat with uniform groove spacing is applied to a deposition process where heat conduction is mainly based on thermal radiation (such as low-pressure chemical vapor deposition), it will cause uneven wafer deposition.

[0005] In view of the above-mentioned technical problems, this application provides a new crystal boat, batch processing apparatus and low-pressure vapor deposition method to at least partially solve the above problems. Summary of the Invention

[0006] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] To address the existing problems, this application provides a wafer boat for depositing a product film layer on the front side of a product wafer, including an adjacent first region and a second region. The first region includes a plurality of product wafer trenches, and the second region includes a monitoring wafer trench. The second region is located on the bearing side of the product wafer trenches. The product wafer trenches are used to bear the product wafers and expose the back side of the product wafers, and there is a first spacing between the product wafer trenches. The monitoring wafer trenches are used to bear monitoring wafers and expose the back side of the monitoring wafers, and there is a second spacing between the first region and the second region. The ratio of the first spacing to the second spacing is positively correlated with the ratio of the thermal emissivity of the back side film layer of the product wafer to the back side film layer of the monitoring wafer.

[0008] In some embodiments of this application, when the thermal emissivity of the back film layer of the monitoring wafer is greater than that of the back film layer of the product wafer, the second spacing dimension is greater than the first spacing; when the thermal emissivity of the back film layer of the monitoring wafer is equal to that of the back film layer of the product wafer, the second spacing dimension is equal to the first spacing; when the thermal emissivity of the back film layer of the monitoring wafer is less than that of the back film layer of the product wafer, the second spacing dimension is less than the first spacing.

[0009] In some embodiments of this application, the product film layer comprises silicon nitride and / or polycrystalline silicon.

[0010] In some embodiments of this application, the monitoring wafer backside film layer includes silicon nitride, silicon oxide, or silicon.

[0011] In some embodiments of this application, the back film layer of the monitoring wafer comprises silicon, the back film layer of the product wafer comprises silicon nitride, the product film layer comprises silicon nitride, and the ratio of the first spacing to the second spacing is 2 to 3.

[0012] In some embodiments of this application, the second region includes a plurality of the monitoring wafer slots, and the monitoring wafer slots have a fourth spacing, which is the same as the second spacing.

[0013] In some embodiments of this application, the wafer boat further includes a third region adjacent to the first region, the third region being located on the side of the first region away from the second region, the third region including a monitoring wafer trench, and the third region having a third spacing with the first region, the third spacing being the same as the first spacing.

[0014] In some embodiments of this application, the crystal boat further includes a fourth region located on the side of the monitoring wafer trough away from the first region, the fourth region including a dummy wafer trough for carrying a dummy wafer.

[0015] According to another aspect of this application, a batch processing apparatus for low-pressure vapor deposition is provided, comprising a chamber and a crystal boat disposed within the chamber as described above.

[0016] According to another aspect of this application, a low-pressure vapor deposition method is provided, which is performed using the batch processing apparatus described above, wherein a monitoring wafer is carried on each of the monitoring wafer slots, a product wafer is carried on each of the product wafer slots, and a product film layer is deposited on the product wafer.

[0017] According to the crystal boat, batch processing apparatus, and low-pressure vapor deposition method of the present application, by adjusting the ratio of the first spacing and the second spacing based on the ratio of the thermal emissivity of the back film layer of the product wafer and the back film layer of the monitoring wafer, the influence of the difference in thermal emissivity between the back film layer of the product wafer and the back film layer of the monitoring wafer on the thickness of the product film layer deposited on the front side of the product wafer can be reduced, thereby improving the uniformity of the product film layer thickness between product wafers at different positions on the crystal boat. Attached Figure Description

[0018] The following drawings, which are incorporated herein by reference and are used to understand this application, illustrate embodiments of the invention and their descriptions to explain the principles of the invention.

[0019] Figure 1A A partial structural schematic diagram of a crystal boat according to an embodiment of this application is shown.

[0020] Figure 1B A schematic diagram of a ship having a virtual wafer, a product wafer, and a monitoring wafer, according to an embodiment of this application, is shown.

[0021] Figure 2A A partial structural schematic diagram of a crystal boat according to another embodiment of this application is shown.

[0022] Figure 2B A schematic diagram of a ship having a virtual wafer, a product wafer, and a monitoring wafer, according to another embodiment of this application, is shown.

[0023] In the attached image:

[0024] 101 First spacing;

[0025] 102 Second spacing;

[0026] 103 Third spacing;

[0027] 104. Fourth spacing;

[0028] 110 First District;

[0029] 111 Product wafer slots;

[0030] 112 Product Wafers;

[0031] 120 Second District;

[0032] 121 Monitoring wafer troughs;

[0033] 122 Monitoring wafers;

[0034] 130 Third District;

[0035] 140 Fourth District;

[0036] 141. Fictitious wafer racks;

[0037] 142 Dummy wafer. Detailed Implementation

[0038] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0039] It should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this application to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0040] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0041] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0043] In the prior art, a crystal boat typically has a first region and a second region. The first region includes multiple product wafer slots for carrying product wafers, and the second region includes monitoring wafer slots for carrying monitoring wafers. The second region is located on the carrying side of the first region. The slot spacing within the crystal boat is typically uniform; that is, the spacing between adjacent product wafer slots is usually consistent with the spacing between adjacent product wafer slots and monitoring wafer slots.

[0044] However, when a wafer boat with uniform groove spacing is applied to a deposition process where heat conduction is mainly based on thermal radiation, such as LPCVD (Low Pressure Chemical Vapor Deposition), it will cause uneven wafer deposition.

[0045] Taking the deposition of polycrystalline silicon on product wafers using LPCVD as an example, in semiconductor manufacturing processes, to save costs, dummy wafers (also called fake wafers, used to fill empty areas within the reaction chamber) and monitoring wafers with specific surface materials are used. The reaction chamber has very low pressure, and heat propagation is mainly through inter-wafer thermal radiation. Different materials have different thermal emissivity, and some film deposition processes are temperature-sensitive. For example, when polycrystalline silicon is deposited on the front side of the product wafer, and the back side material of the product wafer is silicon and the back side material of the monitoring wafer is silicon nitride, the product wafer closest to the monitoring wafer in the first region is wafer A. Below wafer A is wafer B. The front side of wafer A faces silicon nitride, while the front side of wafer B faces the bottom surface of wafer A, which is made of silicon. Silicon nitride has a higher thermal radiation efficiency than silicon. The polycrystalline silicon deposition process is sensitive to temperature. Under the same trench spacing, wafer A receives more heat on the front side than wafer B. Wafer A has a higher surface temperature and a thicker film layer, which leads to uneven film layer deposition thickness between wafer A and wafer B, affecting product yield.

[0046] To address at least one of the aforementioned technical problems, this application provides a wafer boat for depositing a product film layer on the front side of a product wafer, comprising an adjacent first region and a second region. The first region includes a plurality of product wafer trenches, and the second region includes a monitoring wafer trench. The second region is located on the bearing side of the product wafer trenches. The product wafer trenches are used to bear the product wafers and expose the back side of the product wafers, and a first spacing is provided between the product wafer trenches. The monitoring wafer trenches are used to bear monitoring wafers and expose the back side of the monitoring wafers, and a second spacing is provided between the first region and the second region. The ratio of the first spacing to the second spacing is positively correlated with the ratio of the thermal emissivity of the back side film layer of the product wafer to the thermal emissivity of the back side film layer of the monitoring wafer.

[0047] According to the crystal boat of this application, by adjusting the ratio of the first spacing and the second spacing based on the ratio of the thermal emissivity of the back film layer of the product wafer and the back film layer of the monitoring wafer, the influence of the difference in thermal emissivity between the back film layer of the product wafer and the back film layer of the monitoring wafer on the thickness of the product film layer deposited on the front side of the product wafer can be reduced, thereby improving the uniformity of the product film layer thickness of different product wafers.

[0048] To fully understand this application, detailed steps and structures will be presented in the following description to illustrate the technical solutions proposed in this application. Preferred embodiments of this application are described in detail below; however, in addition to these detailed descriptions, this application may have other implementation methods.

[0049] The following is for reference. Figures 1A-1B and Figures 2A-2BThis application describes a wafer boat according to several embodiments. The wafer boat is used to deposit a product film layer on the front side of a product wafer 112, including adjacent first regions 110 and second regions 120. The first region 110 includes a plurality of product wafer trenches 111, and the second region 120 includes a monitoring wafer trench 121. The second region 120 is located on the carrying side of the product wafer trenches 111. The product wafer trenches 111 are used to carry the product wafer 112 and expose the back side of the product wafer 112, and a first spacing 101 is provided between the product wafer trenches 111. The monitoring wafer trench 121 is used to carry a monitoring wafer 122 and expose the back side of the monitoring wafer 122, and a second spacing 102 is provided between the first region 110 and the second region 120. The ratio of the first spacing 101 to the second spacing 102 is positively correlated with the ratio of the thermal emissivity of the back side film layer of the product wafer 112 to the ratio of the thermal emissivity of the back side film layer of the monitoring wafer 122.

[0050] In actual production, the ratio of the first spacing 101 and the second spacing 102 can be adjusted based on the ratio of the thermal emissivity of the back film layer of product wafer 112 and the back film layer of monitoring wafer 122. The larger the ratio of the thermal emissivity of the back film layer of product wafer 112 to that of monitoring wafer 122, the larger the ratio of the first spacing 101 and the second spacing 102 should be, and vice versa. Adjusting the ratio of the first spacing 101 and the second spacing 102 by adjusting the ratio of the thermal emissivity of the back film layer of product wafer 112 to that of monitoring wafer 122 can reduce the impact of differences in the thermal emissivity of the back film layers on the thickness of the product film layer deposited on the front side of product wafer 112, thereby improving the uniformity of the product film layer thickness among product wafers 112 at different locations on the wafer boat.

[0051] In some embodiments, the crystal boat can be placed inside the furnace tube. When depositing the product film layer on the front side of the product wafer 112, the product film layer is affected not only by the thermal radiation from the back side film layer but also by the gas flow distribution. It is understood that when the gas flow rate is uniformly distributed within the furnace tube, the ratio of the first spacing 101 and the second spacing 102 can be determined based on the difference in thermal emissivity between the back side film layer of the product wafer 112 and the back side film layer of the monitoring wafer 122. Wherein, as... Figure 1A and Figure 1B As shown, when the thermal emissivity of the back film layer of the monitoring wafer 122 is greater than that of the back film layer of the product wafer 112, the size of the second spacing 102 can be larger than the first spacing 101, that is, the ratio of the first spacing 101 to the second spacing 102 is less than 1; when the thermal emissivity of the back film layer of the monitoring wafer 122 is equal to that of the back film layer of the product wafer 112, the size of the second spacing 102 can be equal to that of the first spacing 101, that is, the ratio of the first spacing 101 to the second spacing 102 is equal to 1; Figure 2A and Figure 2BAs shown, when the thermal emissivity of the back film layer on the monitoring wafer 122 is less than that on the back film layer of the product wafer 112, the size of the second spacing 102 can be smaller than the first spacing 101, that is, the size of the first spacing 101 and the second spacing 102 is greater than 1. Of course, the size between the second spacing 102 and the first spacing 101 is not limited to the above situation. Since the deposition rate of the product film layer is also related to the gas flow distribution, the gas flow distribution needs to be considered when adjusting the size of the second spacing 102 and / or the first spacing 101, and then adjusted according to the actual situation.

[0052] In some embodiments, the product film deposited on the front side of the product wafer 112 by the boat in this embodiment may be a low-pressure deposited film layer whose deposition process is heat-sensitive. For example, the product film layer may include silicon nitride and / or polysilicon, or it may include other types of low-pressure deposited films whose deposition process is heat-sensitive, without limitation.

[0053] In some embodiments, the back film layer of the monitoring wafer 122 carried in the crystal boat of this embodiment may include silicon nitride, silicon oxide or silicon, etc., and there is no limitation thereto.

[0054] In some embodiments, the back film layer of the product wafer 112 carried in the crystal boat in this embodiment may also be silicon nitride, silicon oxide or silicon, etc., and there is no limitation thereto.

[0055] The thermal emissivity (emissivity) reference values ​​for silicon nitride, silicon oxide, and silicon are typically within 0.1 μm to 1 μm. For example, at 500°C to 800°C, the thermal emissivity (emissivity) reference value for silicon nitride is 0.9 μm, for silicon oxide it is 0.6 μm to 0.7 μm, and for silicon / polycrystalline silicon it is 0.6 μm to 0.7 μm. In this embodiment, by first determining the materials of the back-side films of the monitoring wafer 122 and the product wafer 112, and then determining the thermal emissivity of the back-side films, the ratio of the first spacing 101 and the second spacing 102 can be adjusted according to the ratio of the thermal emissivity of the back-side films of the product wafer 112 and the monitoring wafer 122. This reduces the impact of the difference in thermal emissivity of the back-side films on the thickness of the product film deposited on the front side of the product wafer 112, and improves the uniformity of the product film thickness between product wafers 112 at different locations on the wafer boat.

[0056] In some embodiments, the specific ratio and / or specific spacing size of the first spacing 101 and the second spacing 102 can be obtained through experiments or simulations, and the specific method is not limited. It should be noted that when obtaining the specific ratio and / or specific spacing size of the first spacing 101 and the second spacing 102, in addition to considering the influence of the thermal emissivity of different materials such as the back film layer of the product wafer 112 and the back film layer of the monitoring wafer 122, the influence of gas flow distribution on deposition can also be considered, thereby obtaining the optimal specific ratio and / or optimal specific spacing size. Under the optimal specific ratio and / or optimal specific spacing size, the uniformity of the product film thickness of different product wafers 112 can be significantly improved.

[0057] For example, taking a monitoring wafer 122 with a back film layer comprising silicon and a product wafer 112 with a back film layer comprising silicon nitride, and a product film layer comprising silicon nitride as an example, the thermal emissivity of the back film layer of the product wafer 112 is greater than that of the back film layer of the monitoring wafer 122. The ratio of the first spacing 101 to the second spacing 102 can be 2 to 3, for example, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, etc. Within this ratio range, the problem of uneven product film thickness of different product wafers 112 caused by the difference in thermal emissivity between the back film layers of product wafer 112 and monitoring wafer 122 can be significantly reduced. It should be noted that the optimal value of the above ratio range can be obtained through experiments or simulations.

[0058] In some embodiments, the second region 120 may include one or more monitoring wafer slots 121, which is not limited thereto. When the second region 120 includes multiple monitoring wafer slots 121, there is a fourth spacing 104 between the monitoring wafer slots 121, which is the same as the second spacing 102. The monitoring wafer 122 closest to the first region 110 in the second region 120 is wafer C, and the product wafer 112 closest to the second region in the first region 110 is wafer D. The front side of wafers C and D faces the back film layer of the monitoring wafer 122. By making the fourth spacing 104 the same as the second spacing 102, it can be achieved that at least wafer C in the monitoring wafers 122 accurately reflects the product film layer condition on the surface of the product wafer 112. Wherein, as Figure 1A As shown, when the second spacing 102 is larger than the first spacing 101, the fourth spacing 104 is the same as the second spacing 102 and also larger than the first spacing 101; Figure 2A As shown, when the size of the second spacing 102 is smaller than that of the first spacing 101, the fourth spacing 104 is the same as that of the second spacing 102 and is also smaller than that of the first spacing 101.

[0059] In some embodiments, such as Figures 1A-1B or Figures 2A-2BAs shown, the wafer boat may further include a third region 130 adjacent to the first region 110. The third region 130 is located on the side of the first region 110 away from the second region 120. The third region 130 includes a monitoring wafer trench 121. There is a third spacing 103 between the third region 130 and the first region 110. The third spacing 103 is the same as the first spacing 101. The monitoring wafer 122 and the product wafer 112 carried on the monitoring wafer trench 121 of the third region 130 both face the back film layer of the product wafer 112. By making the third spacing 103 the same as the first spacing 101, the thermal radiation received by the front side of the monitoring wafer 122 is the same as that received by the front side of the product wafer 112. The thickness of the product film layer deposited on the front side of the product wafer 112 can be reflected through the monitoring wafer 122.

[0060] In some embodiments, such as Figures 1A-1B or Figures 2A-2B As shown, the wafer boat also includes a fourth region 140, located on the side of the monitoring wafer tank 121 away from the first region 110. For example, the fourth region 140 may be located on the side of the second region 120 away from the first region 110, or on the side of the third region 130 away from the first region 110. The fourth region 140 includes a dummy wafer tank 141, which is used to support a dummy wafer 142. Typically, the thermal emissivity of the surface film of the dummy wafer 142 differs significantly from that of the product wafer 112. By placing the fourth region 140 on the side of the monitoring wafer tank 121 away from the first region 110, the dummy wafer 142 is located between the monitoring wafer 122 and the product wafer 112, with the monitoring wafer 122 also present. This avoids the thermal emissivity difference between the surface film of the dummy wafer 142 and the back film of the product wafer 112 from having a deteriorating effect on the fabrication of the product film.

[0061] It should be noted that in some embodiments not shown, the crystal boat includes multiple combined regions, including adjacent first region 110 and second region 120. For example, the crystal boat includes two adjacent combined regions, namely a first combined region and a second combined region, wherein the first combined region is located on the bearing side of the second combined region, and the second region 120 in the second combined region is reused as the third region 130 of the first combined region.

[0062] According to another aspect of this application, a batch processing apparatus is provided. The batch processing apparatus is used for low-pressure vapor deposition and includes a chamber and a crystal boat disposed within the chamber.

[0063] The crystal boat can be implemented as described above, as explained in the previous text, and will not be repeated here. It can be understood that the crystal boat can be placed within the chamber; that is, during the use of the batch processing device, the crystal boat is placed within the chamber.

[0064] In some embodiments, the batch processing apparatus may be implemented as a vertical hot tube or other suitable apparatus, without limitation.

[0065] According to another aspect of this application, a low-pressure vapor deposition method is provided, which is carried out using a batch processing apparatus, wherein a monitoring wafer 122 is carried on each monitoring wafer tank 121, a product wafer 112 is carried on each product wafer tank 111, and a product film layer is deposited on the product wafer 112.

[0066] For example, low-pressure vapor deposition methods can be LPCVD or THALD (Thermal Atomic Layer Deposition), etc., which are not limited here.

[0067] Among them, the batch processing device can be implemented as the batch processing device mentioned above, which can be referred to in the above introduction, and will not be repeated here.

[0068] In summary, the crystal boat, batch processing apparatus, and low-pressure vapor deposition method according to the embodiments of this application, by adjusting the ratio of the first spacing and the second spacing based on the ratio of the thermal emissivity of the back film layer of the product wafer and the back film layer of the monitoring wafer, can reduce the impact of the difference in thermal emissivity between the back film layer of the product wafer and the back film layer of the monitoring wafer on the thickness of the product film layer deposited on the front side of the product wafer, and improve the uniformity of the product film layer thickness of different product wafers.

[0069] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0070] Similarly, it should be understood that, in order to simplify this application and aid in understanding one or more aspects of the application, various features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, the point of application is that the corresponding technical problem can be solved with fewer features than all of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0071] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0072] It should be noted that the above embodiments are illustrative of this application and not limiting of it, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

Claims

1. A wafer boat for depositing a product film layer on the front side of a product wafer, characterized in that, It includes an adjacent first area and a second area, the first area including multiple product wafer slots, and the second area including a monitoring wafer slot, the second area being located on the bearing side of the product wafer slot; The product wafer slots are used to support the product wafers and expose the back side of the product wafers, and there is a first spacing between the product wafer slots; the monitoring wafer slots are used to support the monitoring wafers and expose the back side of the monitoring wafers, and there is a second spacing between the first area and the second area. The ratio of the first spacing to the second spacing is positively correlated with the ratio of the thermal emissivity of the back film layer of the product wafer to the thermal emissivity of the back film layer of the monitoring wafer.

2. The crystal boat as described in claim 1, characterized in that, When the thermal emissivity of the back film layer of the monitoring wafer is greater than that of the back film layer of the product wafer, the second spacing dimension is greater than the first spacing dimension; when the thermal emissivity of the back film layer of the monitoring wafer is equal to that of the back film layer of the product wafer, the second spacing dimension is equal to the first spacing dimension; when the thermal emissivity of the back film layer of the monitoring wafer is less than that of the back film layer of the product wafer, the second spacing dimension is less than the first spacing dimension.

3. The crystal boat as described in claim 1, characterized in that, The product film layer includes silicon nitride and / or polycrystalline silicon.

4. The crystal boat as described in claim 1, characterized in that, The back film layer of the monitoring wafer includes silicon nitride, silicon oxide, or silicon.

5. The crystal boat as described in claim 1, characterized in that, The back film layer of the monitoring wafer includes silicon, the back film layer of the product wafer includes silicon nitride, the product film layer includes silicon nitride, and the ratio of the first spacing to the second spacing is 2 to 3.

6. The crystal boat as described in claim 1, characterized in that, The second region includes a plurality of the monitoring wafer slots, and the monitoring wafer slots have a fourth spacing, which is the same as the second spacing.

7. The crystal boat as described in claim 1, characterized in that, The wafer boat also includes a third region adjacent to the first region, the third region being located on the side of the first region away from the second region, the third region including a monitoring wafer trench, and the third region having a third spacing with the first region, the third spacing being the same as the first spacing.

8. The crystal boat as described in claim 1 or 7, characterized in that, The crystal boat also includes a fourth region located on the side of the monitoring wafer trough away from the first region. The fourth region includes a dummy wafer trough for holding dummy wafers.

9. A batch processing apparatus for low-pressure vapor deposition, characterized in that, It includes a chamber and a crystal boat as described in any one of claims 1 to 8 that can be disposed within the chamber.

10. A low-pressure vapor deposition method, characterized in that, The batch processing apparatus as described in claim 9 is used, wherein the monitoring wafer is carried on each of the monitoring wafer slots, the product wafer is carried on each of the product wafer slots, and the product film layer is deposited on the product wafer.

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