Polycrystalline silicon thin film deposition equipment, preparation method and micro-electro-mechanical device

Abstract

The invention provides polycrystalline silicon thin film deposition equipment, a preparation method and a micro electro-mechanical device. The polycrystalline silicon thin film deposition equipment comprises a furnace tube, a wafer boat and a gas supply tube, the crystal boat is arranged in the furnace tube, the crystal boat comprises a plurality of layers of supporting pieces which are arranged at intervals in the length direction of the furnace tube, the distance between every two adjacent layers of supporting pieces is larger than 3.6 mm, and the supporting pieces are used for supporting a wafer on which a polycrystalline silicon thin film is to be deposited; the gas supply pipe is arranged in the furnace tube and is arranged on the peripheral side of the wafer, the gas supply pipe is provided with a plurality of gas supply holes along the length direction of the furnace tube, and gas of the gas supply holes flows from the edge of the wafer to the center of the wafer. According to the invention, the uniformity of preparation of the polycrystalline silicon thin film can be improved.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor technology, and in particular to a polysilicon thin film deposition device, a preparation method and a micro-electromechanical device. Background Art

[0002] With the development of semiconductor manufacturing technology, chemical vapor deposition (CVD) has been widely used as a polysilicon thin film process. By setting up a reaction chamber, the reaction gas is introduced into the reaction chamber, so as to deposit a polysilicon thin film on the surface of the wafer. However, in the related art, because the groove spacing of the wafer boat in the reaction chamber is set too small, for example, less than or equal to 3.6mm, the uniformity of the prepared polysilicon thin film is poor. Summary of the invention

[0003] The embodiments of the present application provide a polysilicon thin film deposition device, a preparation method and a micro-electromechanical device, which can improve the uniformity of the polysilicon thin film and improve the product yield at least to a certain extent.

[0004] A first aspect of an embodiment of the present application provides a polysilicon thin film deposition device, comprising:

[0005] Furnace pipes;

[0006] A wafer boat is arranged inside the furnace tube, the wafer boat comprises multiple layers of support members arranged at intervals along the length direction of the furnace tube, the spacing between two adjacent layers of the support members is greater than 3.6 mm, and the support members are used to support wafers to be deposited with polycrystalline silicon thin films;

[0007] The gas supply pipe is arranged inside the furnace tube and around the wafer. The gas supply pipe is provided with a plurality of gas supply holes along the length direction of the furnace tube. The gas flow direction of the gas supply holes is from the edge of the wafer to the center of the wafer.

[0008] In some embodiments of the present application, based on the aforementioned solution, the distance between two adjacent layers of the support members ranges from 4.46 mm to 5.06 mm.

[0009] In some embodiments of the present application, based on the aforementioned solution, the distance between two adjacent layers of the support members is 4.76 mm.

[0010] A second aspect of the present application provides a method for preparing a polycrystalline silicon thin film, which is applied to a polycrystalline silicon thin film deposition device as described in any one of the first aspects. The method comprises:

[0011] Placing a wafer on the support of the wafer boat, and controlling the support to drive the wafer to rotate;

[0012] Controlling the gas supply pipe to pass the reaction gas into the furnace tube from the gas supply hole;

[0013] Within a set time period, the reaction gas flows from the edge of the wafer to the center of the wafer to deposit a polysilicon film on the surface of the wafer.

[0014] In some embodiments of the present application, based on the above solution, controlling the gas supply pipe to pass the reaction gas into the furnace tube from the gas supply hole includes:

[0015] The gas supply pipe is controlled to introduce a preset amount of reaction gas into the furnace tube from the gas supply hole, wherein the preset amount has a value range of 580 ml / min-600 ml / min.

[0016] In some embodiments of the present application, based on the aforementioned solution, the set duration has a value range of 615 minutes to 630 minutes.

[0017] In some embodiments of the present application, based on the above solution, after the polysilicon film is deposited on the surface of the wafer, the method further includes:

[0018] The polysilicon film is annealed according to a preset annealing temperature and a preset annealing temperature, wherein the preset annealing temperature ranges from 940 degrees Celsius to 960 degrees Celsius, and the preset annealing time ranges from 40 minutes to 50 minutes.

[0019] A third aspect of an embodiment of the present application provides a micro-electromechanical system device, comprising a wafer and a polysilicon film disposed on the wafer, wherein the polysilicon film is prepared according to any method described in the second aspect.

[0020] In some embodiments of the present application, based on the above solution, the difference between the film thickness of the polysilicon film in the central area of ​​the wafer and the film thickness in the edge area of ​​the wafer is in the range of: The ratio of the area of ​​the central region to the area of ​​the wafer is in the range of 2%-3%.

[0021] In some embodiments of the present application, based on the aforementioned solution, the stress range of the polysilicon film is: 50 MPa-60 MPa.

[0022] The technical solution provided in the embodiments of the present application has at least the following technical effects or advantages:

[0023] The polysilicon thin film deposition equipment provided in the embodiment of the present application sets the distance between two adjacent layers of support members to be greater than 3.6 mm. Compared with traditional equipment, the distance between two adjacent layers of support members is increased, thereby increasing the concentration of gas diffused to the surface of the wafer, and further increasing the concentration of gas entering the center area of ​​the wafer, thereby reducing the difference in film thickness of the polysilicon thin film in the center area and the edge area of ​​the wafer, improving the uniformity of the film thickness and stress distribution of the polysilicon thin film, and thereby improving the product yield.

[0024] The above description is only an overview of the technical solution provided by the embodiment of the present application. In order to more clearly understand the technical means of the embodiment of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and easy to understand, the specific implementation method of the embodiment of the present application is listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present disclosure. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0026] Figure 1 A schematic structural diagram of a polysilicon thin film deposition device according to an embodiment of the present application is shown;

[0027] Figure 2 Shows Figure 1 A partial enlarged view of the middle A;

[0028] Figure 3 A flow chart showing a method for preparing a polycrystalline silicon thin film according to an embodiment of the present application is shown;

[0029] FIG4( a ) shows a schematic diagram of the film thickness of an existing polysilicon thin film;

[0030] FIG4( b ) is a schematic diagram showing the film thickness of a polysilicon thin film according to an embodiment of the present application;

[0031] FIG5( a ) shows a schematic diagram of a stress distribution curve of a conventional polysilicon film;

[0032] FIG5( b ) is a schematic diagram showing a stress distribution curve of a polysilicon film according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that the term "plurality" appearing herein includes two or more than two situations.

[0034] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of variation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0035] As used herein, "parallel", "perpendicular", and "equal" include the situations described and situations similar to the situations described, and the range of the similar situations is within the acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism may be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity may also be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, wherein the acceptable deviation range of approximate equality may be, for example, the difference between the two equalities is less than or equal to 5% of either one.

[0036] It will be understood that when a layer or an element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present between the layer or element and the other layer or substrate.

[0037] With the development of semiconductor manufacturing technology, chemical vapor deposition (CVD) has been widely used as a polysilicon thin film process. In addition, low pressure chemical vapor deposition (LPCVD) is also widely used for polysilicon thin film deposition. It is a chemical vapor deposition technology performed under relatively low pressure conditions. In the LPCVD process, chemical reactions usually occur at high temperatures, and pre-specified reaction gases are introduced into a reaction chamber (such as a furnace tube) to deposit materials on the surface of a wafer (such as a wafer) to form a polysilicon thin film. The reaction chamber is usually equipped with a wafer boat to load the wafer. When working, the wafer is placed on the wafer boat and is in a closed reaction chamber. The reaction gas is then transported to the interior of the reaction chamber. The reaction gas and the wafer react chemically in a high temperature environment to deposit a thin film on the surface of the wafer, namely a polysilicon thin film.

[0038] At present, the uniformity of doped polysilicon thin films prepared by LPCVD is about ±40%, which is far less than the uniformity of intrinsic amorphous silicon thin films. During the research and development process, the inventors found that when LPCVD is used to prepare doped polysilicon thin films, since the diffusion direction of the reaction gas is from the edge of the wafer to the center of the wafer, the polysilicon thin film is restricted by the diffusion of the reaction gas to the wafer surface during the deposition process, resulting in a significant decrease in the uniformity of the deposited film layer.

[0039] The uniform polysilicon film in the chip is widely used in various semiconductor products, such as MEMS (Micro-Electro-Mechanical System) microphones, MEMS speakers, MEMS oscillators and other products. In these products, polysilicon film is often used as a vibration element. The polysilicon film is stimulated to vibrate by an external signal, so as to detect the capacitance of the entire structure to achieve the function of detecting sound, vibration, etc. Therefore, polysilicon film with excellent performance is very important in the application of the above products. With the development of semiconductor integrated circuits, the preparation of polysilicon film has become a common technical means. However, in the process of large-scale mass production, how to achieve high yield and uniform polysilicon at different positions on the same wafer has become a technical problem that needs to be solved urgently.

[0040] In the related art, LPCVD is usually a vertical or horizontal furnace tube type equipment. The wafer boat is arranged inside the furnace tube. The wafer boat has multiple layers of support members arranged at intervals along the length direction of the furnace tube. The support members are used to support the wafers. Therefore, multiple wafers are also arranged at intervals along the length direction of the furnace tube. The spacing between adjacent support members is small, usually 3.6mm.

[0041] However, the inventors found during the research and development process that when preparing polysilicon thin film, since the reaction gas diffuses from the edge of the wafer to the center of the wafer, and the wafer is constantly rotating during the film growth process, when the spacing between the supports is small, the gas concentration at the edge of the wafer is high due to the influence of temperature and gas flow, and polysilicon thin film is preferentially generated. When the reaction gas reaches the middle area of ​​the wafer, the gas concentration decreases, resulting in the problem that the film thickness in the middle area of ​​the grown polysilicon thin film is small and the thickness at the edge is large, that is, the problem of poor in-chip uniformity of the polysilicon thin film grown on the same wafer. The uniformity of the polysilicon thin film is closely related to the performance of the MEMS product. Therefore, if the in-chip uniformity of the polysilicon thin film grown on the same wafer is poor, the product yield of the MEMS product will also be poor.

[0042] Based on the above, a first aspect of an embodiment of the present application provides a polysilicon thin film deposition device, which can improve the uniformity of the polysilicon thin film and improve the product yield at least to a certain extent.

[0043] The polysilicon thin film deposition equipment according to the embodiment of the present application is described below with reference to specific drawings.

[0044] See also Figure 1 , showing a schematic structural diagram of a polysilicon thin film deposition device according to an embodiment of the present application; Figure 2 Shows Figure 1 A partial enlarged view of point A in the middle.

[0045] like Figure 1 and Figure 2 As shown, the first aspect of the embodiment of the present application provides a polycrystalline silicon thin film deposition device, including: a furnace tube 1, a wafer boat 2 and a gas supply pipe 3. The wafer boat 2 is arranged inside the furnace tube 1, and the wafer boat 2 includes a plurality of support members 21 arranged at intervals along the length direction of the furnace tube 1, and the spacing between two adjacent layers of the support members 21 is greater than 3.6 mm, and the support members 21 are used to support the wafer to be deposited with a polycrystalline silicon thin film; the gas supply pipe 3 is arranged inside the furnace tube 1 and arranged on the peripheral side of the wafer, and the gas supply pipe 3 is provided with a plurality of gas supply holes 31 along the length direction of the furnace tube 1, and the gas flow direction of the gas supply hole 3 is from the edge of the wafer to the center of the wafer.

[0046] It should be noted that, under the same gas supply volume of the gas supply pipe 3, the spacing between the two adjacent layers of the support members 21 is positively correlated with the gas concentration diffused to the surface of the wafer, that is, the larger the spacing between the two adjacent layers of the support members 21, the higher the gas concentration diffused to the surface of the wafer; in addition, before the gas concentration on the surface of the wafer reaches the saturation concentration, the gas concentration on the surface of the wafer is positively correlated with the film thickness of the polycrystalline silicon thin film deposited on the surface of the wafer, that is, the higher the gas concentration entering the surface of the wafer, the thicker the deposited film layer.

[0047] In some embodiments of the present application, based on the aforementioned scheme, the spacing between two adjacent layers of the support members 21 ranges from 4.46 mm to 5.06 mm; for example, the spacing between two adjacent layers of the support members 21 may be 4.46 mm, 4.56 mm, 4.60 mm, 4.76 mm, 4.80 mm, 4.85 mm, 4.92 mm or 5.06 mm, etc., which is adjusted according to actual process requirements and is not limited here.

[0048] It should be noted that the wafer in this embodiment can be a semiconductor element formed on a substrate, such as a semiconductor wafer at any stage in the process of integrated circuits or discrete devices. In one embodiment, the wafer includes a very low dielectric constant dielectric layer and a metal layer on a semiconductor substrate. The wafer can be a photomask, a semiconductor wafer, or other workpieces known to ordinary technicians in the field of electronic component manufacturing. In at least some embodiments, the wafer includes any material used to manufacture any integrated circuit, passive (e.g., capacitors, inductors) and active (e.g., transistors, photodetectors, lasers, diodes) microelectronic components. The wafer may include insulating materials (e.g., dielectric materials) that separate such active and passive microelectronic components from one or more conductive layers formed on top of them. In one embodiment, the wafer is a semiconductor substrate including one or more dielectric layers, such as silicon, silicon dioxide or other dielectric materials. In one embodiment, the wafer is one or more layers, and the one or more layers of the wafer may include a conductive layer, a semiconductor layer, an insulating layer, or any combination of the foregoing layers.

[0049] It should be noted that the gas concentration in the embodiment of the present application may be the percentage of the gas volume in a unit space. For example, the percentage of the gas volume in a unit space of the reaction chamber in the furnace tube 1, when the gas concentration is large, it means that the gas molar amount in the unit space of the reaction chamber is large, and conversely, when the gas concentration is small, it means that the gas molar amount in the unit space of the reaction chamber is small.

[0050] In some embodiments, the multi-layer support members 21 are arranged at equal intervals or at unequal intervals along the length direction of the wafer boat 2. When the multi-layer support members 21 are arranged at equal intervals along the length direction of the wafer boat 2, under the same gas supply volume of the gas supply pipe 3, the gas concentration in the gap between two adjacent layers of the multi-layer support members 21 is roughly the same, so that the film thickness of the polycrystalline silicon thin film deposited on the same batch of wafers is basically the same, which is suitable for batch production of polycrystalline silicon thin films of a certain film thickness. When the multi-layer support members 21 are arranged at unequal intervals along the length direction of the wafer boat 2, the gas concentration in the gap between two adjacent layers of the multi-layer support members 21 is different, so that polycrystalline silicon thin films of different film thicknesses can be deposited on the same batch of wafers, which is suitable for small-scale simultaneous preparation of polycrystalline silicon thin films of different film thicknesses.

[0051] Therefore, compared with the conventional polysilicon thin film deposition equipment in which the spacing between adjacent supports 21 is usually 3.6 mm, the embodiment of the present application analyzes the relationship between the spacing between adjacent supports 21 and the gas concentration diffused to the wafer surface, and finds that under the same gas supply volume of the gas supply pipe 3, the spacing between two adjacent layers of supports 21 is positively correlated with the gas concentration diffused to the wafer surface, that is, the larger the spacing, the higher the gas concentration diffused to the wafer surface. On this basis, the present application comprehensively considers improving the gas concentration on the wafer surface and the production efficiency of the same batch of wafers (the larger the spacing, the fewer wafers that can be carried in the wafer boat 2), and sets the spacing between adjacent supports 21 to be greater than 3.6 mm, for example, 4.46 mm-5.06 mm, that is, by increasing the spacing between two adjacent layers of supports 21, the gas concentration that can enter the gap between adjacent supports 21 is increased. Since the reaction gas diffuses from the edge to the center of the wafer, when the gas concentration at the edge reaches the saturation concentration and the polysilicon film at the edge no longer grows, the gas concentration entering the center area of ​​the wafer can be higher, thereby increasing the film thickness of the polysilicon film grown in the center area, reducing the difference in film thickness of the polysilicon film in the center and edge areas of the wafer, improving the uniformity of film thickness and stress distribution of the polysilicon film, and thereby improving product yield.

[0052] See also Figure 3 , showing a flow chart of a method for preparing a polycrystalline silicon thin film according to an embodiment of the present application.

[0053] like Figure 3 As shown, the second aspect of the embodiment of the present application provides a method for preparing a polycrystalline silicon thin film, which is applied to the polycrystalline silicon thin film deposition device as described in any one of the first aspects, and the method includes but is not limited to:

[0054] Step S1. placing the wafer on the support of the wafer boat, and controlling the support to drive the wafer to rotate;

[0055] For example: 100 wafers, 110 wafers, 115 wafers, 120 wafers, etc. can be placed in a wafer boat, so that polysilicon thin films can be deposited on multiple wafers at the same time later, thereby improving mass production efficiency.

[0056] In some embodiments, the wafer may be a silicon wafer, or a combination of a silicon wafer and a silicon dioxide film layer grown on the silicon wafer.

[0057] Step S2. Control the gas supply pipe to pass the reaction gas into the furnace tube from the gas supply hole;

[0058] In some embodiments, the reaction gas may be silane or chlorosilane, and polysilicon is generated by the cracking of silane or dichlorosilane at high temperature. In addition, in some embodiments, the embodiments of the present application intend to make the prepared polycrystalline silicon film conductive, and therefore, phosphorus or boron is also doped into the polycrystalline silicon film to achieve the preparation of a conductive polycrystalline silicon film, and the preparation gas of phosphorus or boron is phosphine and borane, so when growing doped polycrystalline silicon, gases such as silane and phosphine need to be introduced into the furnace tube.

[0059] In some embodiments of the present application, based on the above solution, controlling the gas supply pipe to pass the reaction gas into the furnace tube from the gas supply hole includes:

[0060] The gas supply pipe is controlled to pass a preset amount of reaction gas into the furnace tube from the gas supply hole, wherein the preset amount ranges from 580 ml / min to 600 ml / min, for example, the reaction gas is passed in at a preset amount of 580 ml / min, or, the reaction gas is passed in at a preset amount of 590 ml / min, or, the reaction gas is passed in at a preset amount of 600 ml / min.

[0061] Step S3. Within a set time period, the reaction gas flows from the edge of the wafer to the center of the wafer to deposit a polysilicon thin film on the surface of the wafer.

[0062] Therefore, based on the polycrystalline silicon thin film deposition equipment with the spacing between adjacent support members set to 4.46mm-5.06mm, the gas concentration of the reaction gas entering the gap between adjacent support members is increased. Since the reaction gas diffuses from the edge to the center of the wafer, when the gas concentration at the edge reaches the saturation concentration and the polycrystalline silicon film at the edge position no longer grows, the gas concentration entering the central area of ​​the wafer can be higher, thereby increasing the film thickness of the polycrystalline silicon thin film grown in the central area, reducing the difference in film thickness of the polycrystalline silicon thin film in the central area and the edge area of ​​the wafer, and improving the uniformity of the film thickness of the polycrystalline silicon thin film; and since there is a corresponding relationship between the film thickness and stress, that is, the greater the film thickness, the smaller the stress, when the uniformity of the film thickness is improved, the uniformity of the stress distribution of the film is also improved accordingly, thereby being able to improve the overall yield of the product.

[0063] In some embodiments of the present application, based on the aforementioned solution, the set duration has a value range of 615 minutes to 630 minutes.

[0064] It should be noted that the existing polysilicon thin film usually has a thin film thickness in the center area and a thick film thickness in the edge area. In the prior art, a process time of 600 minutes is used to deposit the polysilicon thin film. In the embodiment of the present application, since the concentration of the gas entering the center area increases, more process time is required to deposit the polysilicon thin film in the center area. Therefore, the main process time is extended to 615 minutes to 630 minutes, for example, 615 minutes, 620 minutes, 625 minutes, 630 minutes, etc., to meet the film deposition requirements of the center area.

[0065] In some embodiments of the present application, based on the above solution, after the polysilicon film is deposited on the surface of the wafer, the method further includes:

[0066] The polysilicon film is annealed according to a preset annealing temperature and a preset annealing temperature, wherein the preset annealing temperature ranges from 940 degrees Celsius to 960 degrees Celsius, and the preset annealing time ranges from 40 minutes to 50 minutes.

[0067] It should be noted that if the thickness of the deposited polysilicon film is uneven and the stress distribution is uneven, then if the stress of the deposited polysilicon film does not meet the stress requirements of the product, it is difficult to uniformly adjust the stress of the polysilicon film due to the uneven stress distribution, thereby reducing the product yield. In the embodiment of the present application, since the stress distribution of the prepared polysilicon film is uniform, when the film stress is subsequently adjusted, it can be uniformly increased or decreased to reduce the process difficulty.

[0068] In an embodiment of the present application, the stress of the polysilicon film is adjusted by an annealing process, for example, the polysilicon film is annealed at an annealing temperature of 940 degrees Celsius, 950 degrees Celsius or 960 degrees Celsius for an annealing time of 40 minutes, 45 minutes, 48 ​​minutes or 50 minutes, so that the stress of the polysilicon film meets the set stress requirement. For example, the stress range of the polysilicon film prepared by the method is: 50 MPa-60 MPa, for example, 50 MPa, 53 MPa, 54 MPa, 55 MPa, 58 MPa or 60 MPa.

[0069] A third aspect of an embodiment of the present application provides a micro-electromechanical system device, comprising a wafer and a polysilicon film disposed on the wafer, wherein the polysilicon film is prepared according to any method described in the second aspect.

[0070] In some embodiments, the micro-electromechanical device includes, but is not limited to, for example, a MEMS (Micro-Electro-Mechanical System) microphone, a MEMS speaker, a MEMS oscillator, and the like.

[0071] In some embodiments of the present application, based on the above solution, the difference between the film thickness of the polysilicon film in the central area of ​​the wafer and the film thickness in the edge area of ​​the wafer is in the range of: For example or Etc.; wherein, the ratio of the area of ​​the central region to the area of ​​the wafer is in the range of 2%-3%, for example, 2%, 2.5% or 3%, etc. The central region may be an area with a radius of 30 mm with the center of the wafer as the center, and the edge region may be other areas except the central region.

[0072] As shown in Figure 4(a) and Figure 4(b), Figure 4(a) shows a schematic diagram of the film thickness of the existing polysilicon thin film, and Figure 4(b) shows a schematic diagram of the film thickness of the polysilicon thin film of the embodiment of the present application, where Mean represents the average value of the film thickness, and Range represents the maximum difference in the film thickness between the middle region and the edge region of the film. By comparison, it can be seen that compared with the prior art, the difference between the film thickness of the middle region and the film thickness of the edge of the polysilicon thin film in the embodiment of the present application is reduced, so the uniformity of the film is increased.

[0073] In order to further understand the change in the film thickness of the polysilicon film in the embodiment of the present application, which is equivalent to the film thickness of the polysilicon film in the prior art, further explanation is given below through Table 1 and Table 2.

[0074] Table 1 Experimental table of film thickness of polysilicon thin film in the prior art

[0075]

[0076] Table 2 Experimental table of film thickness of polysilicon thin film in the embodiment of the present application

[0077]

[0078] It can be clearly seen from the comparison between Table 1 and Table 2 that the polycrystalline silicon thin film prepared by the deposition equipment based on the increased support member spacing in the embodiment of the present application has a significantly smaller difference in film thickness between the middle area and the edge area than that in the prior art, thereby improving the uniformity of the film thickness.

[0079] In some embodiments of the present application, based on the aforementioned solution, the stress range of the polysilicon film is: 50 MPa-60 MPa, for example, 50 MPa, 55 MPa, 56 MPa, 58 MPa or 60 MPa.

[0080] As shown in FIG5(a) and FIG5(b), FIG5(a) shows a schematic diagram of the stress distribution curve of the existing polysilicon film, and FIG5(b) shows a schematic diagram of the stress distribution curve of the polysilicon film of the embodiment of the present application, where STRESS represents stress (MPA, megapascals), SCAN PATH represents the scanning path, and line represents the curve. By comparison, it can be seen that compared with the prior art, the stress distribution curve of the polysilicon film of the embodiment of the present application has a smaller fluctuation, so the stress distribution uniformity of the film layer is better.

[0081] In the above description, the technical details such as the composition of each layer of the product are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. Although each embodiment is described separately above, it does not mean that the measures in each embodiment cannot be used in combination to advantage.

[0082] In addition, those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure is limited to these examples. Based on the concept of the present disclosure, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present disclosure as described above, which are not provided in detail for the sake of simplicity.

[0083] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional 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 disclosure.

Claims

1. A polysilicon thin film deposition device, characterized in that: include: Furnace pipes; A wafer boat is arranged inside the furnace tube, the wafer boat comprises multiple layers of support members arranged at intervals along the length direction of the furnace tube, the spacing between two adjacent layers of the support members is greater than 3.6 mm, and the support members are used to support wafers to be deposited with polycrystalline silicon thin films; The gas supply pipe is arranged inside the furnace tube and around the wafer. The gas supply pipe is provided with a plurality of gas supply holes along the length direction of the furnace tube. The gas flow direction of the gas supply holes is from the edge of the wafer to the center of the wafer.

2. The polysilicon thin film deposition equipment according to claim 1, characterized in that: The spacing between two adjacent layers of the support members ranges from 4.46 mm to 5.06 mm.

3. The polysilicon thin film deposition equipment according to claim 1 or 2, characterized in that: The distance between two adjacent layers of the support members is 4.76 mm.

4. A method for preparing a polycrystalline silicon thin film, characterized in that: Applied to the polysilicon thin film deposition device according to any one of claims 1 to 3, the method comprises: Placing a wafer on the support of the wafer boat, and controlling the support to drive the wafer to rotate; Controlling the gas supply pipe to pass the reaction gas into the furnace tube from the gas supply hole; Within a set time period, the reaction gas flows from the edge of the wafer to the center of the wafer to deposit a polysilicon film on the surface of the wafer.

5. The method according to claim 4, characterized in that The controlling the gas supply pipe to pass the reaction gas into the furnace tube from the gas supply hole comprises: The gas supply pipe is controlled to introduce a preset amount of reaction gas into the furnace tube from the gas supply hole, wherein the preset amount has a value range of 580 ml / min-600 ml / min.

6. The method according to claim 4, characterized in that The setting duration ranges from 615 minutes to 630 minutes.

7. The method according to claim 4, characterized in that After the polysilicon film is deposited on the surface of the wafer, the method further comprises: The polysilicon film is annealed according to a preset annealing temperature and a preset annealing temperature, wherein the preset annealing temperature ranges from 940 degrees Celsius to 960 degrees Celsius, and the preset annealing time ranges from 40 minutes to 50 minutes.

8. A micro-electromechanical device, characterized in that: The micro-electromechanical device comprises a wafer and a polysilicon film disposed on the wafer, and the polysilicon film is prepared according to the method according to any one of claims 4 to 7.

9. The micro-electromechanical device according to claim 8, characterized in that: The difference between the film thickness of the polysilicon film in the center area of ​​the wafer and the film thickness in the edge area of ​​the wafer is in the range of: The ratio of the area of ​​the central region to the area of ​​the wafer is in the range of 2%-3%.

10. The micro-electromechanical device according to claim 8, characterized in that: The stress range of the polysilicon film is 50 MPa-60 MPa.

Images