Point-contact helical-tooth silicon boat and silicon boat helical-tooth processing method

Abstract

A point-contact helical-tooth silicon boat comprises a top plate, a flange and a groove rod, wherein the groove rod is provided with a plurality of helical teeth, and the helical teeth are provided with a left tooth surface, a right tooth surface, a front tooth surface, an upper tooth surface and a lower tooth surface, wherein the left tooth surface is adjacent to the front tooth surface and transitions through a first fillet surface, the right tooth surface is adjacent to the front tooth surface and transitions through a second fillet surface, the upper tooth surface is located at the upper ends of the left tooth surface, the right tooth surface and the front tooth surface, and the lower tooth surface is located at the lower ends of the left tooth surface, the right tooth surface and the front tooth surface, and at least part of the position between the upper tooth surface and the left tooth surface, the right tooth surface and the front tooth surface transitions through a first curved surface, and when a silicon wafer is placed on the helical teeth, point contact between the silicon wafer and the helical teeth can be achieved, and the contact position will be on the first curved surface or on the first boundary line, so that the influence on heat treatment can be reduced through point contact, and the first curved surface is set at a position close to the horizontal plane to provide greater supporting force.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor processing, and in particular relates to a point-contact helical-tooth silicon boat and a method for processing the helical teeth of the silicon boat. Background Art

[0002] Silicon boats are commonly used in semiconductor material heat treatment processes and are generally made of silicon. Silicon boats can be categorized as either vertical or horizontal. Vertical boats typically consist of a top plate, flange, and groove rods. The groove rods are the primary component supporting the silicon wafers, making groove rod processing crucial. Depending on the specific application requirements, the groove rods' groove teeth vary in shape, including straight, stepped, and beveled. Even with the same beveled teeth, the angle of inclination and the processing method can produce different shapes, resulting in varying support for the wafers, ranging from point support to linear support or even surface support. In theory, a large contact area minimizes wafer deformation during heat treatment. However, in practice, due to machining and assembly errors among the multiple groove rods, the supporting surfaces of the different groove rods are rarely aligned. Consequently, even theoretical surface contact results in point or linear contact. A significant drawback of this large contact area is that temperature unevenness during heat treatment can cause the wafer to adhere to the contact surface, rendering the wafer scrapped. Line contact is also subject to issues such as machining errors and assembly errors, and may actually be in a point contact state. Furthermore, the purity of the silicon boat material will also affect heat treatment. If point contact is used, the effect of material purity on heat treatment will also be reduced. According to geometric principles, three points determine a plane. Therefore, if a three-point contact design is used, even if machining errors and assembly errors have an impact, the actual contact point position offset is very small. In this way, the design solution can be controlled, and the situation where surface contact is converted to point contact will not occur. In other words, the support force requirements are met in the design, but deformation or damage occurs due to the low support force.

[0003] In a vertical silicon boat, point contact groove rods have great advantages over other methods such as surface contact and line contact, but how to design the point contact groove rod structure is still a major technical challenge. Summary of the Invention

[0004] In view of the above-mentioned prior art, the object of the present invention is to provide a point-contact helical-tooth silicon boat and a method for machining the helical teeth of the silicon boat.

[0005] The technical solution of the present invention is achieved as follows: a point-contact helical-tooth silicon boat comprises a top plate, a flange and a groove rod, the groove rod is provided with a plurality of helical teeth, the helical teeth are provided with a left tooth surface, a right tooth surface, a front tooth surface, an upper tooth surface and a lower tooth surface, the left tooth surface is adjacent to the front tooth surface and transitions through a first fillet surface, the right tooth surface is adjacent to the front tooth surface and transitions through a second fillet surface, the upper tooth surface is located at the upper ends of the left tooth surface, the right tooth surface and the front tooth surface, the lower tooth surface is located at the lower ends of the left tooth surface, the right tooth surface and the front tooth surface, at least part of the position between the upper tooth surface and the left tooth surface, the right tooth surface and the front tooth surface transitions through a first curved surface, there is a first boundary line between the first curved surface and the upper tooth surface, a first tangent of the first curved surface at the center position of the length of the first boundary line is made in a plane passing through the center position of the length of the first boundary line and perpendicular to the first boundary line, the first tangent is within the angle range from a plane parallel to the horizontal plane to a plane parallel to the upper tooth surface and includes a position parallel to the horizontal plane and a position parallel to the helical tooth surface.

[0006] The beneficial effect of this design is that when the silicon wafer is placed on the bevel teeth, point contact between the silicon wafer and the bevel teeth can be achieved, and the contact position will be on the first curved surface or on the first boundary line. In this way, the impact on heat treatment can be reduced through point contact. The first curved surface is set at a position close to the horizontal plane to provide greater supporting force. Compared with other point contact designs, the deformation of the silicon wafer is smaller, and compared with line contact, the impact on heat treatment is smaller. Therefore, this design can achieve better overall performance.

[0007] Furthermore, there is a second boundary line between the first curved surface and the left tooth surface, the right tooth surface and the front tooth surface. A second tangent of the first curved surface is drawn at the center position of the length of the second boundary line in a plane perpendicular to the second boundary line. The second tangent is within the angle range from the plane parallel to the horizontal plane to the plane perpendicular to the upper tooth surface and does not include the position parallel to the horizontal plane and the position perpendicular to the oblique tooth surface. This design can make the second boundary line of the first curved surface away from the silicon wafer. Since the second boundary line is not chamfered and is relatively sharp, it is easy to scratch the silicon wafer and cause the silicon wafer to be scrapped. Therefore, in theory, the farther away from the silicon wafer, the better. However, due to space limitations, the size of the oblique teeth generally has a certain range, and the curvature radius of the first curved surface cannot be designed too small, otherwise it will affect the supporting performance of the first curved surface.

[0008] Furthermore, a plurality of upper mounting positions are provided on the lower side of the top plate, and the same number of lower mounting positions as the upper mounting positions on the top plate are provided on the upper side of the flange. The upper end of the groove rod matches the mounting position on the top plate, and the lower end of the groove rod matches the lower mounting position of the flange. The top plate and the flange are fixed together through the groove rod installation. In this way, the top plate, flange and groove rod can be directly installed and used together without the need for other parts. The structure is simple and convenient to use and manufacture.

[0009] Furthermore, the radial extension length of the bevel teeth is greater than the width, so that the contact point between the silicon wafer and the bevel teeth is closer to the center of the silicon wafer. Due to the point contact design, in order to obtain better support performance and further reduce deformation, the support point moves radially a certain distance to balance the mass of the outside and inside of the support point. Theoretically, the silicon wafer is divided into three equal parts, and the position of the center of gravity of each silicon wafer is the ideal support point position. However, in practice, considering that the inner support is more uniform and the outer side is in a suspended state, the actual contact point should be designed outside the two-thirds diameter circle of the silicon wafer, but close to the position of the two-thirds diameter circle of the silicon wafer. This will have a better balancing effect and reduce the deformation of the silicon wafer during heat treatment.

[0010] Furthermore, the groove rods include a first groove rod, a second groove rod and a third groove rod, the second groove rod and the third groove rod are symmetrically arranged between the flange and the top plate, the first groove rod adopts a symmetrical design and is arranged on the symmetry axis of the second groove rod and the third groove rod, the oblique teeth of the first groove rod extend toward the center of the silicon boat, the second groove rod and the third groove rod extend radially and are inclined at a certain angle away from the first groove rod so that the contact points of the first groove rod, the second groove rod and the third groove rod with the silicon wafer are distributed on the three vertices of an approximately equilateral triangle, so that each contact point is evenly stressed and the overall deformation of the silicon wafer is smaller.

[0011] Furthermore, the first groove rod is provided with a first tooth bottom surface, the second groove rod is provided with a second tooth bottom surface, and the third groove rod is provided with a third tooth bottom surface. The second tooth bottom surface is parallel to the third tooth bottom surface, and the first tooth bottom surface is perpendicular to the second tooth bottom surface and the third tooth bottom surface. In this way, the silicon wafer can be moved from one side of the silicon boat, making it convenient to take and place the silicon wafer.

[0012] Furthermore, a second curved surface, a third curved surface, a retracting curved surface and a feed curved surface are provided between the upper tooth surface and the left tooth surface and the right tooth surface. The second curved surface and the third curved surface are arranged in a mirror-symmetrical manner on the bevel tooth, and the retracting curved surface and the feed curved surface are arranged in a mirror-symmetrical manner on the bevel tooth. In this way, processing the non-contact position can avoid the silicon wafer being scratched by contact with the bevel tooth edge in the event of sudden accidents such as vibration. The same tool can be used to process other positions, further reducing the possibility of scratching the silicon wafer at other positions. If the same tool is used for processing, the design is convenient and the programming processing is also simple, which can improve the processing efficiency. There is no need for a better chamfering tool for chamfering processing, and the same tool can be used for one-time forming.

[0013] Furthermore, the second curved surface and the third curved surface are cylindrical surfaces, so they can be directly processed using a rounded corner tool with an arc-shaped cross-section. Such a tool is easier to process and correct, especially in the processing of silicon materials, which requires diamond grinding. There is serious uneven wear when processing rounded corners or curved surfaces, and the tool needs to be corrected frequently. The arc-shaped tool does not require complex processing to obtain a high-precision curved surface, so it has better economy.

[0014] Furthermore, the first curved surface, the second curved surface, the third curved surface, the retracted curved surface and the feed curved surface are processed and formed using the same curved surface tool. The processing surface on the cross section of the curved surface tool is an arc with a radius of 10mm-60mm. When the inclination angle of the bevel tooth is greater than 6 degrees, the angle between the first tangent and the horizontal plane is in the range of 0 degrees to 6 degrees, so that the first curved surface has a tendency to extend horizontally or obliquely downward at the first tangent position, and the first curved surface has a tendency to extend obliquely downward at the second tangent position. Controlling the angle of the first tangent can reduce the possibility of the silicon wafer being scratched by contacting the first boundary line when tilted at a certain angle when placed or vibrating, so that the transition angle at the first boundary line is smaller. In theory, the second tangent should also be tilted downward as much as possible, but due to the size, the space for changing the angle is limited, so it can be tilted downward as much as possible.

[0015] A method for processing bevel teeth of a silicon boat includes at least the following steps: installing a grooved groove rod onto a processing jig, ensuring that the bevel tooth surface is parallel to the tool rotation plane, starting to feed along a first curve to process the feed curved surface, feeding along a first straight line in the tangent direction of the first curve to process the second curved surface, feeding along a circular arc line tangent to the first straight line to process the first curved surface, continuing to feed along a second straight line in the tangent direction of the circular arc line to process the third curved surface, feeding along a second curve tangent to the second straight line to process the exit curved surface. In this way, a single fillet tool can be used to process multiple curved surfaces, the processing efficiency is high, the transition between the curved surfaces is relatively smooth, no cross-sections will occur, and the same position will not be repeatedly processed, which is more economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a three-dimensional schematic diagram of a point-contact helical-tooth silicon boat according to the present invention;

[0017] Figure 2 This is a horizontal cross-sectional schematic diagram of a point-contact helical-tooth silicon boat according to the present invention;

[0018] Figure 3 This is a schematic diagram of a point-contact helical-tooth silicon boat flange of the present invention;

[0019] Figure 4 This is a schematic diagram of a point-contact helical-tooth silicon boat top plate of the present invention;

[0020] Figure 5 This is a schematic diagram of the front view of the helical gear;

[0021] Figure 6 for Figure 5 Schematic diagram of partial cross-section of helical gear at radial position AA;

[0022] Figure 7 for Figure 5 Schematic cross-sectional view of the helical gear at BB in the axial direction;

[0023] Figure 8It is a schematic diagram of the cross section of the curved tool;

[0024] Figure 9 This is a schematic diagram of the local helical teeth of the first groove bar;

[0025] Figure 10 This is a three-dimensional schematic diagram of the partial helical teeth of the first groove rod;

[0026] Figure 11 It is a partial three-dimensional schematic diagram of the second groove rod;

[0027] Figure 12 It is a partial three-dimensional schematic diagram of the second groove rod;

[0028] Figure 13 Schematic diagram of the second groove rod being installed on the slotting jig;

[0029] Figure 14 This is a side view of the second groove rod installed on the slotting jig;

[0030] Figure 15 This is a side view of the second groove rod installed on the chamfering jig;

[0031] Figure 16 This is a top view of the second groove rod installed on the chamfering jig;

[0032] Figure 17 This is a top view of the second groove rod after it is installed on the chamfering jig and rotated horizontally;

[0033] Figure 18 This is a three-dimensional schematic diagram of the second chamfering jig;

[0034] Figure 19 Schematic diagram of the cutting path of the curved tool of the present invention. DETAILED DESCRIPTION

[0035] As needed, detailed embodiments of the present invention are disclosed herein, but it should be understood that the disclosed embodiments are merely exemplary of the present invention, and the present invention may be implemented in different and alternative forms. The accompanying drawings are not necessarily drawn to scale, and certain features may be exaggerated or reduced to show the details of a particular component. Therefore, the specific structural and functional details disclosed herein should not be understood as having a limiting meaning, but merely as a representative basis to teach those skilled in the art to adopt the present invention differently. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0036] like Figure 1-11As shown, a point-contact helical-tooth silicon boat includes a top plate 1, a flange 3, and a groove rod 2. The groove rod 2 is provided with a plurality of helical teeth 4. The helical teeth 4 are provided with a left tooth surface 41, a right tooth surface 42, a front tooth surface 43, an upper tooth surface 44, and a lower tooth surface 45. The left tooth surface 41 is adjacent to the front tooth surface 43 and transitions through a first fillet surface 46. The right tooth surface 42 is adjacent to the front tooth surface 43 and transitions through a second fillet surface 47. The upper tooth surface 44 is located at the upper ends of the left tooth surface 41, the right tooth surface 42, and the front tooth surface 43. The lower tooth surface 45 is located at the lower end of the left tooth surface 41, the right tooth surface 42 and the front tooth surface 43. At least part of the upper tooth surface 44 transitions with the left tooth surface 41, the right tooth surface 42 and the front tooth surface 43 through a first curved surface 48. A first intersection line 49 exists between the first curved surface 48 and the upper tooth surface 44. A first tangent line 40 of the first curved surface 48 is drawn at the center of the length of the first intersection line 49 in a plane passing through the center of the length of the first intersection line 49 and perpendicular to the first intersection line 49, as shown in FIG. Figure 6 As shown, the first tangent line 40 is within the angle range from a plane parallel to the horizontal plane 62 to a plane parallel to the upper tooth surface 44 and includes a position parallel to the horizontal plane 62 and a position parallel to the oblique tooth surface 44 .

[0037] like Figure 1-11 As shown, there is a second boundary line 50 between the first curved surface 48 and the left tooth surface 41, the right tooth surface 42 and the front tooth surface 43. A second tangent line 51 of the first curved surface 48 is drawn at the center of the length of the second boundary line 50 in a plane perpendicular to the second boundary line 50, as shown in FIG. Figure 6 As shown, the second tangent line 51 is within the angle range from a plane parallel to the horizontal plane to a plane perpendicular to the upper tooth surface 44 and does not include a position parallel to the horizontal plane and a position perpendicular to the oblique tooth surface 44 .

[0038] like Figure 3 Figure 4 As shown, a plurality of upper mounting positions 101 are provided on the lower side of the top plate 1, and the same number of lower mounting positions 103 as the upper mounting positions 101 of the top plate 1 are provided on the upper side of the flange 3. The upper end of the groove rod 2 matches the upper mounting position 101 of the top plate 1, and the lower end of the groove rod 2 matches the lower mounting position 103 of the flange 3. The top plate 1 and the flange 3 are installed and fixed together through the groove rod 2.

[0039] like Figure 2 As shown, the radially extending length of the helical teeth 4 is greater than the width, so that the contact point between the silicon wafer and the helical teeth 4 is closer to the center of the silicon wafer.

[0040] like Figure 1 and Figure 2As shown, the groove bar 2 includes a first groove bar 210, a second groove bar 220 and a third groove bar 230. The second groove bar 220 and the third groove bar 230 are symmetrically arranged between the flange 3 and the top plate 1. The first groove bar 210 adopts a symmetrical design and is arranged on the symmetry axis of the second groove bar 220 and the third groove bar 230. The oblique teeth 4 of the first groove bar 210 extend toward the center of the silicon boat, and the second groove bar 220 and the third groove bar 230 extend radially and are inclined at a certain angle in the direction away from the first groove bar 210 so that the contact points of the first groove bar 210, the second groove bar 220 and the third groove bar 230 with the silicon wafer are distributed on the three vertices of an approximately equilateral triangle.

[0041] like Figure 1 and Figure 2 As shown, the first groove bar 210 is provided with a first tooth bottom surface 211, the second groove bar 220 is provided with a second tooth bottom surface 221, and the third groove bar 230 is provided with a third tooth bottom surface 231. The second tooth bottom surface 221 is parallel to the third tooth bottom surface 231, and the first tooth bottom surface 211 is perpendicular to the second tooth bottom surface 221 and the third tooth bottom surface 231.

[0042] like Figure 5-11 As shown, a second curved surface 52, a third curved surface 53, a retracting curved surface 54, and an infeed curved surface 55 are provided between the upper tooth surface 44 and the left tooth surface 41 and the right tooth surface 42. The second curved surface 52 and the third curved surface 53 are arranged in mirror-symmetrical fashion on the helical tooth 4, while the retracting curved surface 54 and the infeed curved surface 55 are arranged in mirror-symmetrical fashion on the helical tooth 4. The second curved surface 52 and the third curved surface 53 form cylindrical surfaces.

[0043] The first curved surface 48, the second curved surface 52, the third curved surface 53, the retracted curved surface 54 and the feed curved surface 55 are processed and formed using the same curved surface tool 56. The processed surface on the cross section of the curved surface tool 56 is an arc with a radius of 10mm-60mm. When the inclination angle of the bevel tooth 4 is greater than 6 degrees, the angle between the first tangent 40 and the horizontal plane ranges from 0 degrees to 6 degrees, so that the first curved surface 48 has a tendency to extend horizontally or obliquely downward at the position of the first tangent 40, and the first curved surface 48 has a tendency to extend obliquely downward at the position of the second tangent 51.

[0044] like Figure 11-19 As shown, the method for processing silicon boat bevel teeth includes at least the following steps:

[0045] A. Cutting and shape processing

[0046] A1. Select a silicon rod of suitable size and cut it into a rectangular silicon strip of the size required by the groove rod 2. The size of the silicon strip is basically the same as or slightly larger than the maximum outer dimension of the groove rod 2.

[0047] A2. Grind the outer shape of the silicon strip to obtain a first reference plane 11 and a second reference plane 12 that are parallel to each other, process the third reference plane 13, the third reference plane 13 forms an acute angle with the second reference plane 12, process the first side tooth surface 14 and the second side tooth surface 15, the first side tooth surface 14 forms an obtuse angle with the first reference plane 11, the second side tooth surface 15 forms an obtuse angle with the second reference plane 12, the tooth top surface 16 is perpendicular to the first reference plane 11 and the second reference plane 12, the tooth top surface 16, the first reference plane 11 and the second reference plane 12 are perpendicular to the upper end surface 17, the tooth top surface 16, the first reference plane 11 and the second reference plane 12 are perpendicular to the lower end surface 18, and the tooth top surface 16 and the first side tooth surface 14 and the second side tooth surface 15 are perpendicular to each other. Rounded corner transition: a rounded corner transition is also adopted between the first reference plane 11 and the second reference plane 12 and the first side tooth surface 14 and the second side tooth surface 15. A rounded corner transition is also adopted between the first reference plane 11 and the second reference plane 12 and the third reference plane 13. The above rounded corners can be of the same size or slightly different in the range of 2-6 mm. In the embodiment, the rounded corner radius is 4 mm for chamfering. The angle between the second reference plane 12 and the third reference plane 13 can be about 20-90 degrees, and 61 degrees is taken in the embodiment. The angle between the first side tooth surface 14 and the first reference plane 11 can be the same as the angle between the second side tooth surface 15 and the second reference plane 12, and can be in the range of 0-10 degrees. In the embodiment, 4.5 degrees is taken;

[0048] B. Slotting

[0049] Prepare a slotting jig 19. The slotting jig 19 can make the third reference surface 13 of the silicon strip processed in step A2 be in a horizontal position. The slotting jig 19 is provided with at least a first supporting surface 21 and a second supporting surface 20. The angle between the first supporting surface 21 and the second supporting surface 20 is the same as the angle between the first side tooth surface 14 and the second reference surface 12. The second supporting surface 20 is parallel to the horizontal plane. The first side tooth surface 14 can be adhered to the first supporting surface 21 by a sticky material such as sticky wax, and the third reference surface 13 can be adhered to the second supporting surface 20 by a sticky material such as sticky wax. The sticky wax is paraffin. The jig is fixed to the processing equipment. The tool spindle is tilted at a certain angle to grind, cut and slot multiple times to obtain multiple bevel teeth 4. The tool spindle tilt angle is the same as the angle required for the bevel teeth 4 on the groove rod 2. The angle of the bevel teeth 4 is determined according to the silicon The bevel teeth 4 are designed according to the needs of the wafer heat treatment process. Different bevel teeth 4 designs are provided for silicon wafers of different thicknesses and sizes. The smaller the contact area, the better, provided that the supporting force is satisfied. The bevel teeth 4 and the silicon wafer are usually designed to be in point contact. However, the silicon wafer may change from point contact to surface contact as it softens during heat treatment. Therefore, the specific design depends on the actual situation. In this embodiment, the bevel teeth 4 are parallel to the Y-axis, the angle between the bevel teeth 4 and the X-axis is 89.25 degrees, and the angle between the bevel teeth 4 and the Z-axis is 0.75 degrees. The basic processing method is the same when the angle is within the range of 0 to 20 degrees. After the tool spindle is rotated and tilted 0.75 degrees around the Y-axis for tool setting, CNC processing can be programmed. The sticky wax not only fixes the silicon strip, but also has a good buffering effect to avoid cracking of the silicon strip caused by vibration during processing.

[0050] C. Helical tooth 4-surface processing

[0051] C1. Prepare a processing jig 23. The processing jig 23 is provided with at least a first limiting surface 24, a second limiting surface 25, a third limiting surface 26 and a side limiting surface 27. The side limiting surface 27, the first limiting surface 24 and the second limiting surface 25 are perpendicular to the horizontal plane. The first reference surface 11 can be adhered to the first limiting surface 24 by a sticky material such as sticky wax, the second reference surface 12 can be adhered to the second limiting surface 25 by a sticky material such as sticky wax, the third reference surface 13 can be adhered to the third limiting surface 26 by a sticky material such as sticky wax, and the upper end surface 17 or the lower end surface 18 can be adhered to the side limiting surface 27 by a sticky material such as sticky wax. The initial placement position of the processing jig 23 can ensure that the upper end surface 17 of the groove rod 2 is parallel to the upper end surface 17 when the groove jig 19 fixes the groove rod 2. The curved surface processing and groove processing can be processed with the same equipment, and only the tool needs to be replaced;

[0052] C2. Calculate the horizontal rotation angle of the machining jig 23. In the slotting step B, since the slotting surface forms a certain angle with the YZ plane of the machine tool coordinate axis, which is 10 degrees in the embodiment, the silicon strip must be rotated along the horizontal axis by a certain angle from the slotting step B to the curved surface machining step C, which is 29 degrees in the embodiment. That is, in the slotting step B, the first reference plane 11 and the second reference plane 12 originally form an angle of 61 degrees with the horizontal plane, while in the curved surface machining step C, the first reference plane 11 and the second reference plane 12 form an angle of 90 degrees with the horizontal plane. It is necessary to rotate 29 degrees along the axis parallel to the X-axis, and the tool rotates along the axis parallel to the Y-axis to achieve machining, and cannot rotate along the X-axis. The tool position is adjusted by rotating in a direction parallel to the axis. To ensure that the tooth surface of the helical tooth 4 is parallel to the tool processing plane, the jig must be rotated relative to the tool along an axis perpendicular to the horizontal plane by a certain angle. This calculation can be obtained through complex geometric calculations or with the help of computer-aided design software. That is, a groove bar 2 model is drawn using software, and a line segment or straight line is made perpendicular to the first reference plane 11 or the second reference plane 12. The angle between the line segment or straight line and the tooth surface of the helical tooth 4 is measured, and the degree of the angle is obtained, that is, the horizontal plane rotation angle of the processing jig 23. The straight line or line segment is parallel to the horizontal plane in the C-curved surface processing step. The degree measured in the embodiment is 0.364 degrees.

[0053] C3. Calculate the tool deflection angle. This calculation is also cumbersome using geometric methods. It requires drawing many auxiliary lines to help with the calculation, which is time-consuming and laborious. For example, computer-aided design software, such as CAXA solid design software, UG or Solidworks, all have angle measurement functions, but auxiliary surfaces are needed to help with the measurement. First, draw the groove bar 2 model through the software and construct the basic coordinate system X'Y'Z' or auxiliary surface. The X' axis of the basic coordinate system is perpendicular to the upper end face 17, the Y' axis is perpendicular to the first reference plane 11, the Z' axis is perpendicular to the third reference plane 13, and the auxiliary surface is parallel to the upper end face 17. The basic coordinate system After the X'Y'Z' system or the auxiliary surface is determined, it no longer rotates. At this time, the groove bar 2 first rotates around an axis parallel to the X' axis, and the rotation angle is the same as the complementary angle of the angle between the second reference plane 12 and the third reference plane 13, which is 29 degrees in the embodiment. Then it rotates around an axis parallel to the Z' axis, and the rotation angle is the same as the horizontal plane rotation angle of the processing jig 23 calculated in step C2, which is 4.83 degrees in the embodiment. Finally, the angle measurement tool in the software is used to measure the angle between the tooth surface of the helical tooth 4 and the Y'Z' surface or the auxiliary surface after rotation. This angle is the required deflection angle of the tool, which is 0.656 degrees in the embodiment.

[0054] C4, rotate the curved tool 56 to the angle obtained in C3, and program the tool to perform curved machining.

[0055] Install the grooved groove rod 2 on the processing jig, ensure that the bevel tooth 4 surface is parallel to the rotation plane of the curved surface tool 56, start feeding along the first curve 57, and process the feed surface 55. Feed along the first straight line 58 in the tangent direction of the first curve 57 to process the second curved surface 52. Feed along the arc line 59 tangent to the first straight line 58 to process the first curved surface 48. Continue feeding along the second straight line 60 in the tangent direction of the arc line 59 to process the third curved surface 53. Feed along the second curve 61 tangent to the second straight line 60 to process the exit curved surface 54. During the machining of the second and third groove bars 220 and 230, the first straight line 58 is parallel to the second straight line 60. The curved cutter 56 gradually approaches the bevel tooth 4 as it advances along the first curve 57 and gradually moves away from the bevel tooth 4 as it retracts along the second curve 61. The cross-sectional machining surface of the curved cutter 56 is an arc 63 with a radius of 10 mm to 60 mm. When the inclination angle of the bevel tooth 4 is greater than 6 degrees, the angle between the first tangent and the horizontal plane ranges from 0 degrees to 6 degrees, causing the first curved surface 48 to extend horizontally or downwardly at the first tangent 40. The first curved surface 48 also tends to extend downwardly at the second tangent 51. A circular arc with a radius of 10 mm to 60 mm provides good support, minimizing silicon wafer deformation. During the machining of the first groove bar 210, the first straight line 58 and the second straight line 60 can be angled, with the first straight line 58 parallel to the left tooth surface 41 and the second straight line 60 parallel to the right tooth surface 42.

Claims

1. A silicon boat with point contact helical teeth (4), comprising a top plate (1), a flange (3) and a groove rod (2), wherein the groove rod (2) is provided with a plurality of helical teeth (4), wherein the helical teeth (4) are provided with a left tooth surface (41), a right tooth surface (42), a front tooth surface (43), an upper tooth surface (44) and a lower tooth surface (45), wherein the left tooth surface (41) is adjacent to the front tooth surface (43) and transitions through a first fillet surface (46), the right tooth surface (42) is adjacent to the front tooth surface (43) and transitions through a second fillet surface (47), the upper tooth surface (44) is located at the upper ends of the left tooth surface (41), the right tooth surface (42) and the front tooth surface (43), and the lower tooth surface (45) is located between the left tooth surface (41), the right tooth surface (42) and the front tooth surface At the lower end of the side tooth surface (43), at least a portion of the upper tooth surface (44) and the left tooth surface (41), the right tooth surface (42) and the front tooth surface (43) are transitioned through a first curved surface (48), a first intersection line (49) exists between the first curved surface (48) and the upper tooth surface (44), and a first tangent (40) of the first curved surface (48) is made at the center position of the length of the first intersection line (49) in a plane passing through the center position of the length of the first intersection line (49) and perpendicular to the first intersection line (49), and the first tangent (40) is within an angle range from a plane parallel to the horizontal plane (62) to a plane parallel to the upper tooth surface (44) and includes a position parallel to the horizontal plane (62) and a position parallel to the oblique tooth (4) surface.

2. The point-contact helical-tooth silicon boat according to claim 1, characterized in that: There is a second intersection line (50) between the first curved surface (48) and the left tooth surface (41), the right tooth surface (42) and the front tooth surface (43), and a second tangent line (51) of the first curved surface (48) is drawn at the center position of the length of the second intersection line (50) in a plane perpendicular to the second intersection line (50), and the second tangent line (51) is within the angle range from a plane parallel to the horizontal plane to a plane perpendicular to the upper tooth surface (44) and does not include a position parallel to the horizontal plane and a position perpendicular to the oblique tooth (4) surface.

3. The point-contact helical-tooth silicon boat according to claim 1 or 2, characterized in that: The top plate (1) is provided with a plurality of upper mounting positions (101) on the lower side, and the flange (3) is provided with the same number of lower mounting positions (103) as the upper mounting positions (101) of the top plate (1). The upper end of the groove rod (2) matches the upper mounting position (101) of the top plate (1), and the lower end of the groove rod (2) matches the lower mounting position (103) of the flange (3). The top plate (1) and the flange (3) are fixed together by the groove rod (2).

4. The point-contact helical-tooth silicon boat according to claim 3, characterized in that: The radially extending length of the bevel teeth (4) is greater than the width, so that the contact point between the silicon wafer and the bevel teeth (4) is closer to the center position of the silicon wafer.

5. The point-contact helical-tooth silicon boat according to claim 1 or 2, characterized in that: The groove rods (2) include a first groove rod (210), a second groove rod (220) and a third groove rod (230), the second groove rod (220) and the third groove rod (230) are symmetrically arranged between the flange (3) and the top plate (1), the first groove rod (210) is symmetrically designed and is arranged on the symmetry axis of the second groove rod (220) and the third groove rod (230), the oblique teeth (4) of the first groove rod (210) are extended toward the center of the silicon boat, the second groove rod (220) and the third groove rod (230) are radially extended and tilted at a certain angle in a direction away from the first groove rod (210), so that the contact points of the first groove rod (210), the second groove rod (220) and the third groove rod (230) with the silicon wafer are distributed on the three vertices of an approximately equilateral triangle.

6. The point-contact helical-tooth silicon boat according to claim 5, characterized in that: The first groove rod (210) is provided with a first tooth bottom surface (211), the second groove rod (220) is provided with a second tooth bottom surface (221), and the third groove rod (230) is provided with a third tooth bottom surface (231), the second tooth bottom surface (221) is parallel to the third tooth bottom surface (231), and the first tooth bottom surface (211) is perpendicular to both the second tooth bottom surface (221) and the third tooth bottom surface (231).

7. The point-contact helical-tooth silicon boat according to claim 2, characterized in that: A second curved surface (52), a third curved surface (53), a retracting curved surface (54) and an infeed curved surface (55) are provided between the upper tooth surface (44) and the left tooth surface (41) and the right tooth surface (42); the second curved surface (52) and the third curved surface (53) are arranged on the helical tooth (4) in a mirror-symmetrical manner; and the retracting curved surface (54) and the infeed curved surface (55) are arranged on the helical tooth (4) in a mirror-symmetrical manner.

8. The point-contact helical-tooth silicon boat according to claim 7, characterized in that: The second curved surface (52) and the third curved surface (53) form cylindrical surfaces.

9. The point-contact helical-tooth silicon boat according to claim 8, characterized in that: The first curved surface (48), the second curved surface (52), the third curved surface (53), the retracting curved surface (54) and the infeed curved surface (55) are machined and formed by the same curved surface tool (56); the machined surface on the cross section of the curved surface tool (56) is a circular arc (63) with a radius of 10 mm to 60 mm; when the inclination angle of the bevel tooth (4) is greater than 6 degrees, the angle between the first tangent (40) and the horizontal plane is in the range of 0 degrees to 6 degrees, so that the first curved surface (48) has a tendency to extend horizontally or extend obliquely downward at the position of the first tangent (40); and the first curved surface (48) has a tendency to extend obliquely downward at the position of the second tangent (51).

10. A method for processing helical teeth of a silicon boat, used for processing the helical teeth silicon boat according to claim 9, characterized in that: At least the following steps are included: The groove rod (2) after slotting is mounted on a processing jig, ensuring that the surface of the bevel tooth (4) is parallel to the rotation plane of the curved surface tool (56), starting to feed along the first curve (57), processing the feed curved surface (55), feeding along the first straight line (58) in the tangent direction of the first curve (57), processing the second curved surface (52), feeding along the arc line (59) tangent to the first straight line (58), processing the first curved surface (48), continuing to feed along the second straight line (60) in the tangent direction of the arc line (59), processing the third curved surface (53), feeding along the second curve (61) tangent to the second straight line (60), processing the retraction curved surface (54).

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