Wafer boat capable of preventing wafer from slipping

Abstract

The utility model relates to the technical field of semiconductor devices, and discloses a wafer boat for preventing a wafer from slipping, which comprises a top plate, a flange, a front tooth bar and a rear tooth bar, the front tooth bar and the rear tooth bar are arranged between the top plate and the flange, a plurality of comb-shaped tooth sheets for bearing the wafer are arranged on the front tooth bar and the rear tooth bar in a linear array mode, and the comb-shaped tooth sheets are arranged on the top plate and the flange. The number of the front tooth bars is at least two, tooth pieces on the front tooth bars are of a step structure comprising a lower layer close to the axis of the sky board and a higher layer away from the axis of the sky board, the lower layer of the step structure is a wafer bearing platform, and the higher layer of the step structure is a wafer limiting platform. Each tooth piece on the rear tooth bar is of a platform structure comprising a flat tooth piece platform, the tooth piece platform of the rear tooth bar and the bearing platform of the front tooth bars are kept on the same plane, and a neutral area formed between the two front tooth bars at the foremost end away from the rear tooth bar is used as a wafer inserting inlet. The wafer boat solves the problem that the wafer in the existing short boat is easy to slip off.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor device technology, and more specifically, to a wafer boat to prevent wafers from slipping off the wafer. Background Technology

[0002] Wafers are the main substrate material for manufacturing integrated circuits. High-purity polycrystalline silicon is dissolved and doped with silicon crystal seeds, then slowly pulled out to form cylindrical silicon ingots. After grinding, polishing, and slicing, the silicon ingots are formed into wafers. Domestic production lines mainly use 8-inch and 12-inch wafers. To manufacture various semiconductor devices, wafers need to undergo heat treatment processes, including thin film deposition, annealing, and oxidation. At this time, a carrier that can carry batches of wafers into the high-temperature furnace for heat treatment is needed. This carrier is called a crystal boat.

[0003] A wafer boat mainly consists of two mounting plates, upper and lower, and a toothed rod with several grooves. Grooves of the same height form the wafer support grooves. Wafer boats can be classified by material, such as quartz, silicon, and silicon carbide. Currently, the most common wafer boats on the market are classified by tooth shape as long-toothed boats and short-toothed boats. After undergoing various processing conditions, wafers may warp and bounce under rapid temperature changes, causing changes in the support points for the wafer and posing a risk of slippage. For long-toothed boats, due to the longer teeth, the support point for the wafer is closer to the wafer center (see appendix). Figure 1 The support is stable, and the risk of slippage is very small. However, for short boats, due to their smaller tooth profile, the support point for mounting the wafer is close to the edge of the wafer (see Appendix). Figure 2 The risk of wafers warping or slipping after bouncing is relatively high. If the wafer support point is moved forward by design, this problem can be alleviated to some extent. However, since the wafer insertion size must be guaranteed, the design of the toothed bar position often cannot exceed the range of the upper and lower mounting plates, resulting in little room for variation. Therefore, for short boats, how to design their structure so that the wafers placed inside are not easy to slip has become an urgent problem to be solved in this field. Utility Model Content

[0004] The technical problem to be solved by this utility model is that the support point of the existing short boat carrying the wafer is close to the edge of the wafer, and the risk of the wafer slipping off after warping or jumping is relatively large. In order to overcome the above defects of the prior art, this utility model provides a wafer boat to prevent the wafer from slipping off.

[0005] This invention provides a wafer boat to prevent wafer slippage: it includes a top plate, a flange, a front toothed bar, and a rear toothed bar. The front and rear toothed bars are installed between the top plate and the flange. Multiple comb-shaped toothed plates for supporting wafers are arranged in a linear array on the front and rear toothed bars. The number of front toothed bars is at least two. The toothed plates on the front toothed bars have a stepped structure including a lower layer near the axis of the top plate and a higher layer away from the axis of the top plate. The lower layer of the stepped structure is a wafer carrying platform, and the higher layer of the stepped structure is a wafer positioning platform. The toothed plates on the rear toothed bars have a platform structure including a flat toothed plate platform. The toothed plate platform of the rear toothed bars is on the same plane as the carrying platform of the front toothed bars. The gap area formed between the two front toothed bars at the farthest end away from the rear toothed bars serves as the wafer insertion entrance.

[0006] Compared with the prior art, this application has the following advantages: the front and rear toothed bars are installed between the top plate and the flange to form the entire crystal boat. The multiple comb-shaped teeth on the front and rear toothed bars can carry the wafer. These are the basic structures of the crystal boat. This application further designs the structure of the teeth on the front toothed bar, designing the teeth on the front toothed bar as a stepped bearing structure. Then the bearing platform and the plane of the teeth on the rear toothed bar are for placing the wafer. However, because of the setting of the limiting platform, after the wafer enters from the front toothed bar, it will be restricted by the limiting platform and will not easily slide, thus solving the problem of wafers easily slipping in the existing short boat.

[0007] In one possible implementation, two front teeth are provided, the distance between the inner wall surfaces of the bearing platforms on the two front teeth near the limiting platform is less than the diameter of the wafer, and the distance between the inner wall surfaces of the limiting platforms on the two front teeth away from the bearing platform is greater than the diameter of the wafer.

[0008] In the above scheme, the two foremost front teeth serve as the entry points for wafer insertion, playing a decisive role in whether the wafer is prone to slipping. A key inventive point of this application is the rational design of the spacing between the support platforms and the limiting platforms of these two front teeth. The distance between the inner walls of the support platforms on the two foremost front teeth near the limiting platforms is less than the wafer diameter, while the distance between the inner walls of the limiting platforms on the two foremost front teeth away from the support platforms is greater than the wafer diameter. This allows the wafer to be inserted onto the limiting platforms, and then placed on the plane formed by the toothed plane of the rear teeth and the support platforms. The center of the inserted wafer is located at the center of the triangular plane formed by the rear teeth and the two front teeth, meaning the two front teeth and the rear teeth are distributed on either side of the wafer's center. The limiting platforms then further limit the wafer, preventing it from being pulled out of the support platform after insertion, thus preventing the wafer from slipping.

[0009] In one possible implementation, the two foremost front teeth that are furthest from the rear tooth bar are arranged in a mirror-symmetrical manner, and the plane of symmetry is the plane formed by the axis of the top plate, the axis of the flange, and the axis of the rear tooth bar.

[0010] In the above scheme, the symmetrically arranged front teeth ensure that the bearing platform and the limiting platform are also symmetrically arranged with respect to the axis. Since wafers are generally circular, the symmetrically arranged front teeth are more suitable for wafer insertion into the wafer boat.

[0011] In one possible implementation, the front toothed bar has long or short teeth, and the rear toothed bar has long or short teeth.

[0012] In the above scheme, the crystal boat structure of this application is applicable to both long-toothed crystal boats and short-toothed crystal boats.

[0013] In one possible implementation, the height of the limiting platform relative to the supporting platform is greater than the thickness of the wafer.

[0014] In the above scheme, a higher limiting platform can better prevent the wafer from slipping off the support platform.

[0015] In one possible implementation, the height of the limiting platform relative to the supporting platform is 0.8 mm.

[0016] In the above scheme, the height of a specific crystal boat is set. The height of the limiting platform and the carrying platform not only meet the requirements for placing the wafer, but also affect how many teeth can be set on each crystal boat to place the wafer. Therefore, the limiting platform is not better the higher it is. 0.8mm is suitable for limiting almost all wafers in the industry. At the same time, this height allows the crystal boat to set more teeth and carry more wafers.

[0017] In one possible implementation, the edge of the limiting platform facing the axis of the ceiling is a straight edge or an arc edge that fits the wafer.

[0018] In one possible implementation, the limiting platform has a chamfered edge facing the wafer insertion entrance, and the chamfer is greater than 1 mm.

[0019] In the above scheme, the edge of the limiting platform is defined to prevent damage caused by the robot arm impacting the platform when inserting the wafer. The edge of the limiting platform being a straight edge or a rounded edge that fits the wafer also facilitates wafer positioning and prevents damage to the wafer from protruding teeth.

[0020] In one possible implementation, the lower surface of the top plate is provided with a first mounting groove having the same number as the front and rear toothed bars, and the upper surface of the flange is provided with a second mounting groove having the same number as the front and rear toothed bars and corresponding to the first mounting grooves. The two ends of the front and rear toothed bars are respectively mounted on the first mounting groove and the second mounting groove.

[0021] In the above scheme, when installing the front and rear toothed bars, the ends of the front and rear toothed bars are snapped into the mounting grooves and then glued in place.

[0022] In one possible implementation, the crystal boat is made of quartz, pure silicon, or silicon carbide.

[0023] In the above scheme, since wafers in the semiconductor device field are mostly made of silicon, using similar materials to prepare the crystal boat can reduce contamination of the wafer.

[0024] The advantages of this utility model over the prior art are as follows: The crystal boat of this application effectively improves the risk of wafer deformation and slippage through the groove design of the front toothed bar, and with the insertion depth limit of the rear toothed bar toothed plane, it can well support multiple wafers and the wafers are not easy to slip off. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the support point for mounting the wafer near the center of the wafer in the prior art;

[0026] Figure 2 This is a schematic diagram of the support point for mounting the wafer near the edge of the wafer in the prior art;

[0027] Figure 3 This is an isometric view of the crystal boat of this utility model;

[0028] Figure 4 for Figure 3 Enlarged view of point A in the middle;

[0029] Figure 5 This is a front view of the crystal boat of this utility model;

[0030] Figure 6 for Figure 5 Enlarged view at point B in the middle;

[0031] Figure 7 This is a three-dimensional structural diagram of the top plate of the crystal boat of this utility model.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Top plate; 101. First mounting slot; 2. Flange; 3. Front toothed bar; 301. Bearing platform; 302. Limiting platform; 4. Rear toothed bar; 401. Toothed plate platform; 5. Wafer. Detailed Implementation

[0034] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, specific embodiments of this utility model are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of this utility model, and are not intended to limit the parameter range described in this utility model. Reasonable variations derived therefrom are still within the protection scope of the claims of this utility model.

[0035] In the description of this utility model, it should be noted that the terms "left", "right", "inner", "outer", "front", "rear", "head", "tail", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0036] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0037] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0039] See Figures 3-7 As shown in the figure, this application discloses a crystal boat to prevent wafer 5 from slipping. The crystal boat is mainly composed of three parts, namely a top plate 1, a flange 2 and a toothed bar.

[0040] Mounting grooves are provided on the lower surface of the top plate 1 and the upper surface of the flange 2 for mounting the toothed rod. The mounting groove on the lower surface of the top plate 1 is the first mounting groove 101, and the mounting groove on the upper surface of the flange 2 is the second mounting groove. Figure 5 Only a schematic diagram of the first mounting groove 101 on the top plate 1 is shown. The second mounting groove on the flange 2 is the same as that on the top plate 1, and its view is omitted here. The top plate 1 and flange 2 can be square or round, and are used to install the toothed rod.

[0041] The toothed rod is divided into a front toothed rod 3 and a rear toothed rod 4. Both the front toothed rod 3 and the rear toothed rod 4 are provided with comb-shaped teeth arranged in a linear array to support the wafer 5. The teeth on the front toothed rod 3 have a stepped structure including a lower layer near the axis of the top plate 1 and a higher layer away from the axis of the top plate 1. The lower layer of the stepped structure is the supporting platform 301 of the wafer 5, and the higher layer of the stepped structure is the limiting platform 302 of the wafer 5. The teeth on the rear toothed rod 4 have a platform structure including a flat toothed plate platform 401. The toothed plate platform 401 of the rear toothed rod 4 is on the same plane as the supporting platform 301 of the front toothed rod 3. The toothed rod can be circular, square, or arc-shaped, and teeth of the same height together form the supporting platform 301 of the wafer 5.

[0042] At least two front toothed rods 3 are provided. The gap area formed between the two foremost front toothed rods 3, which are furthest from the rear toothed rod 4, serves as the wafer insertion entrance for the wafer 5. There can be one or two rear toothed rods 4, or any other number. The rear toothed rods 4 are used to limit the insertion depth of the wafer 5. The distance between the inner wall surfaces of the support platforms 301 on the two foremost front toothed rods 3 and the inner wall surfaces of the limiting platforms 302 on the two foremost front toothed rods 3, which are close to the limiting platforms 302, is less than the diameter of the wafer 5. The distance between the inner wall surfaces of the limiting platforms 302 on the two foremost front toothed rods 3, which are furthest from the support platforms 301, is greater than the diameter of the wafer 5.

[0043] The teeth of the front toothed bar 3 can be long or short teeth, and the teeth of the rear toothed bar 4 can also be long or short teeth. The height of the limiting platform 302 relative to the bearing platform 301 needs to be slightly greater than the thickness of the wafer 5, preferably 0.8 mm. The edge of the limiting platform 302 facing the axis of the top plate 1 can be a straight edge or an arc shape that fits the wafer 5, making it easy to hold the wafer 5. The edge of the limiting platform 302 facing the wafer 5 insertion entrance end is chamfered, preferably with a chamfer greater than 1 mm, to prevent the robot arm from impacting the limiting platform 302 and causing damage when inserting the wafer 5.

[0044] The crystal boat can be made of quartz, pure silicon, silicon carbide, etc.

[0045] Compared to Figure 1 and Figure 2Unlike the existing technology where the support point of wafer 5 is either too close or too far from the center of wafer 5, in this embodiment, wafer 5 is positioned on the support platform 301 by the limiting platform 302. The support provided by the support platform 301 is a regional surface support, not a point support. The limiting platform 302 also provides a surface limit rather than a point limit, which makes wafer 5 well fixed and less likely to slip. Example 1

[0046] In a preferred embodiment, the crystal boat mainly consists of a top plate 1, a flange 2, a front toothed rod 3, and a rear toothed rod 4. Two front toothed rods 3 and one rear toothed rod 4 are provided, with the three rods distributed on the same circumference of the top plate 1 and the flange 2. Three first mounting grooves 101 are provided on the lower surface of the top plate 1, and three second mounting grooves are provided on the upper surface of the flange 2. The front toothed rod 3 and the rear toothed rod 4 rest on the first mounting grooves 101 and the second mounting grooves of the top plate 1 and the flange 2 respectively, forming a distributed arrangement.

[0047] Figure 5 Only a schematic diagram of the first mounting groove 101 on the top plate 1 is shown. The second mounting groove on the flange 2 is the same as that on the top plate 1, and its view is omitted here. The top plate 1 and flange 2 can be square or round, and are used to install the toothed rod.

[0048] Two front toothed bars 3 and one rear toothed bar 4 are each equipped with comb-shaped teeth arranged in a linear array to support the wafer 5. The teeth on the front toothed bar 3 have a stepped structure comprising a lower layer near the axis of the top plate 1 and a higher layer away from the axis of the top plate 1. The lower layer of the stepped structure is the support platform 301 of the wafer 5, and the higher layer of the stepped structure is the limiting platform 302 of the wafer 5. The teeth on the rear toothed bar 4 have a platform structure including a flat toothed platform 401. The toothed platform 401 of the rear toothed bar 4 is on the same plane as the support platform 301 of the front toothed bar 3. The toothed bars can be circular, square, or arc-shaped, and teeth of the same height together form the support platform 301 of the wafer 5.

[0049] The distance between the inner wall surfaces of the bearing platforms 301 on the two front toothed rods 3 and the inner wall surfaces of the limiting platforms 302 is less than the diameter of the wafer 5, while the distance between the inner wall surfaces of the limiting platforms 302 on the two front toothed rods 3 and the inner wall surfaces of the limiting platforms 302 away from the bearing platforms 301 is greater than the diameter of the wafer 5. In this embodiment, the two foremost front toothed rods 3 away from the rear toothed rod 4 are arranged in a mirror-symmetrical manner, and the plane of symmetry is the plane containing the axis of the top plate 1, the axis of the flange 2, and the axis of the rear toothed rod 3.

[0050] See details Figure 2 and Figure 4It is known that there are two front toothed rods 3, and the gap area formed between the two front toothed rods 3 serves as the wafer insertion entrance for the wafer 5. The teeth on the two front toothed rods 3 adopt a stepped support structure, with the lower layer being the support platform 301 and the upper layer being the limiting platform 302. When the robot arm places the wafer 5 into the toothed support platform 301, the limiting platform 302 can precisely prevent the wafer 5 from sliding outward. The toothed rod 4 has a different design from the toothed rod 3. The toothed platform 401 of the rear toothed rod 4 does not have the limiting platform 302, but the toothed platform 401 of the rear toothed rod 4 and the support platform 301 of the toothed rod 3 need to be on the same plane.

[0051] The teeth of the front toothed bar 3 and the rear toothed bar 4 can be long teeth or short teeth. The height of the limiting platform 302 relative to the bearing platform 301 needs to be slightly greater than the thickness of the wafer 5, preferably 0.8 mm. The edge of the limiting platform 302 facing the axis of the top plate 1 can be a straight edge or an arc shape that fits the wafer 5, making it easy to hold the wafer 5. The edge of the limiting platform 302 facing the wafer 5 insertion entrance end is chamfered, preferably with a chamfer greater than 1 mm, to prevent the robot arm from impacting the limiting platform 302 and causing damage when inserting the wafer 5.

[0052] The crystal boat can be made of materials such as quartz, pure silicon, or silicon carbide.

[0053] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A wafer boat for preventing wafer sliding, comprising a top plate (1), a flange (2), a front tooth bar (3) and a rear tooth bar (4), the front tooth bar (3) and the rear tooth bar (4) being installed between the top plate (1) and the flange (2), a plurality of comb teeth for carrying wafers (5) being linearly arranged on the front tooth bar (3) and the rear tooth bar (4), characterized in that, The number of the front toothed bars (3) is at least two. The teeth on the front toothed bars (3) are a stepped structure including a lower layer near the axis of the top plate (1) and a higher layer away from the axis of the top plate (1). The lower layer of the stepped structure is the support platform (301) of the wafer (5), and the higher layer of the stepped structure is the limiting platform (302) of the wafer (5). The teeth on the rear toothed bars (4) are a platform structure including a flat toothed platform (401). The toothed platform (401) of the rear toothed bars (4) and the support platform (301) of the front toothed bars (3) are kept on the same plane. The gap area formed between the two front toothed bars (3) at the far end away from the rear toothed bars (4) serves as the wafer insertion entrance of the wafer (5).

2. The wafer boat for preventing wafer slip according to claim 1, wherein, Two front teeth (3) are provided. The distance between the inner wall surfaces of the bearing platforms (301) on the two front teeth (3) and the limiting platform (302) is less than the diameter of the wafer (5). The distance between the inner wall surfaces of the limiting platforms (302) on the two front teeth (3) and the supporting platform (301) is greater than the diameter of the wafer (5).

3. The wafer boat of claim 1, wherein, The two front toothed bars (3) are mirror-symmetric structures and the plane of symmetry is the plane formed by the axis of the top plate (1), the axis of the flange (2) and the axis of the rear toothed bar (4).

4. The wafer boat of claim 1, wherein, The front toothed bar (3) has long or short teeth, and the rear toothed bar (4) has long or short teeth.

5. The wafer boat of claim 1, wherein, The height of the limiting platform (302) relative to the bearing platform (301) is greater than the thickness of the wafer (5).

6. The wafer boat of claim 1, wherein, The height of the limiting platform (302) relative to the bearing platform (301) is 0.8 mm.

7. The wafer boat of claim 1, wherein, The edge of the limiting platform (302) facing the axis of the top plate (1) is a straight edge or an arc edge that fits the wafer (5).

8. The wafer boat of claim 1, wherein, The limiting platform (302) has a chamfered edge at the edge of the wafer (5) insertion entrance, and the chamfer is greater than 1 mm.

9. The wafer boat of claim 1, wherein, The lower surface of the top plate (1) is provided with a first mounting groove (101) that is the same as the total number of front toothed rods (3) and rear toothed rods (4). The upper surface of the flange (2) is provided with a second mounting groove that is the same as the total number of front toothed rods (3) and rear toothed rods (4) and corresponds to the first mounting groove (101). The two ends of the front toothed rods (3) and rear toothed rods (4) are respectively mounted on the first mounting groove (101) and the second mounting groove.

10. The wafer boat of claim 1, wherein, The crystal boat is made of quartz, pure silicon, or silicon carbide.

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