Crucible support shaft device

Abstract

The present invention discloses a crucible support shaft device, comprising: a bracket, provided with a first guide component in a vertical direction; an upper slide seat, guided by the first guide component, and provided with a seat hole; a turntable, mounted on the seat hole through a bearing, and having a center hole; a support shaft, used to support the crucible support; a lower slide seat, guided by the first guide component, and the lower end of the support shaft is mounted on the lower slide seat through a swivel pair; a first drive device; and a second drive device; an upper bellows, the upper end of which is used to connect with the lower furnace mouth of the process chamber, and the lower end is connected with the upper slide seat and is coaxial with the support shaft. The crucible support shaft device according to the present invention has relatively good adaptability.

Description

Technical Field

[0001] The invention relates to a crucible support shaft device. Background Art

[0002] Due to the demanding growth environment of semiconductor crystals, the reaction chamber needs to be sealed and face a given process temperature. In addition, the temperature environment of the reaction area is relatively complex. The axial length of the reaction area in the reaction chamber is generally 500~1000mm. The support shaft used to support the growth crucible is required to have a corresponding working stroke, and the adapted crucible is often required to have a rotation function according to the process requirements. Under this condition, it is necessary to ensure that the support shaft has sufficient rigidity to ensure that the lifting and rotating processes of the crucible support are relatively smooth.

[0003] It should be known that the stiffness of the support shaft is necessarily negatively correlated with the process temperature of the working environment, that is, the higher the process temperature, the worse the stiffness. It is also negatively correlated with the overhang distance relative to the support point, that is, the longer the overhang distance, the worse the stiffness of the support shaft. As mentioned above, first of all, in order to meet the lifting and lowering of the crucible, the support shaft should obviously have a relatively large length to meet the lifting and lowering stroke of the crucible, and at the same time, it should be able to adapt to the problem of maintaining stiffness under the process temperature conditions of the corresponding process.

[0004] For long-stroke rods, reinforcing ribs are generally set on the side to strengthen them, but this structure affects the seal and is difficult to use in the application environment of the present invention. In some implementations, nested multi-stage rod assemblies can also be used, but the drive of the multi-stage cylinder is generally difficult to adapt to relatively high ambient temperatures. For example, the process temperature of the reaction zone is 600°C, which has exceeded the flash point of most hydraulic oils. If gas is used as the working medium, the pipeline configuration of the multi-stage cylinder will also become very difficult. The relevant pipeline needs to follow at least the second-stage cylinder body, which is difficult to work under high process temperature conditions.

[0005] Regarding the crucible support shaft, in order to maintain its rigidity, a follower device may be used in some implementations. The follower device has a guiding relationship with, for example, the process chamber, which is equivalent to providing an auxiliary support device in the middle of the support shaft, thereby making the support shaft have relatively high static and dynamic rigidity. However, the follower auxiliary support often needs to be arranged in the process chamber, and the follower part and the support shaft need to have a sliding fit or a rolling fit. The sliding fit and the rolling fit often require a suitable lubrication environment, and the process chamber often has a relatively high process temperature, for example, above 400°C, and most lubricants are difficult to use. Even high-temperature resistant solid lubricants are difficult to use at higher process temperatures. For example, the maximum process temperature of graphite lubricants is only 450°C. Summary of the invention

[0006] In view of this, an object of the present invention is to provide a crucible support shaft device with relatively good adaptability.

[0007] According to an embodiment of the present invention, a crucible support shaft device is provided, the basic structure of which includes: The bracket is a vertical bracket and is provided with a first guide component in the vertical direction; An upper slide seat is guided by the first guide component and is provided with a seat hole; A turntable, mounted in the seat hole through a bearing and having a center hole; A supporting shaft, extending upward through the central hole, for supporting the crucible support; A lower sliding seat is guided by the first guide member, and the lower end of the support shaft is mounted on the lower sliding seat through a swivel pair; A first driving device, mounted on the bracket, to drive the upper slide and the lower slide to move on the first guide member; and A second driving device is mounted on the lower slide seat to drive the support shaft to rotate; The upper bellows has an upper end for connecting with the lower furnace port of the process chamber, and a lower end connected with the upper slide seat and coaxial with the support shaft.

[0008] Optionally, the upper slide seat and the lower slide seat are connected as a whole via a connecting component; The connecting member is an adjustable device for adjusting the distance between the upper slide seat and the lower slide seat; Correspondingly, a lower bellows is provided between the upper slide seat and the lower slide seat, and the lower bellows is coaxial with the support shaft.

[0009] Optionally, the connecting component includes: A connecting rod, the upper end of which is connected to the upper slide seat; A screw rod is connected to the lower end of the connecting rod to form an integrated rod; A coupling hole is formed on the lower sliding seat to cooperate with the screw rod; The locking nut is screwed together with the screw rod to lock the screw rod after it is adjusted into place.

[0010] Optionally, the upper end of the connecting rod is a cylindrical hinge head or a ball hinge head; Correspondingly, the upper sliding seat is provided with a cylindrical hinge hole or a ball hinge socket.

[0011] Optionally, the first driving device comprises a nut-screw mechanism; Correspondingly, the screw of the nut-screw mechanism is mounted on the bracket via a bearing; The screw nut of the screw nut mechanism is installed on the lower slide seat through a bearing; The upper slide seat and the lower slide seat are linked to each other.

[0012] Optionally, the first driving device further comprises a first synchronous belt mechanism driven by a first motor; Correspondingly, the first synchronous belt mechanism is used to drive the lead screw.

[0013] Optionally, the second driving device is a second synchronous belt mechanism; and a second driven pulley is correspondingly mounted on the lower end of the support shaft.

[0014] Optionally, the bracket is located on one side of the support shaft, and the first guide component is a linear guide rail installed on the bracket; Correspondingly, the upper slide seat and the lower slide seat are arranged on the linear guide rail in a cantilevered manner.

[0015] Optionally, the connection between the upper bellows and the lower furnace port and the upper slide seat is a flange connection.

[0016] Optionally, a plurality of roller assemblies are provided on the upper surface of the turntable, and the roller assemblies are evenly arranged around the support shaft to provide sliding guidance for the support shaft; Correspondingly, the assembly hole of the rotating disk for mounting the roller assembly is a radially arranged elongated hole.

[0017] The crucible support shaft device according to the embodiment of the present invention is a device for supporting the support shaft outside the furnace body, which includes two movable parts, namely, an upper slide and a lower slide. The lower end of the support shaft is installed on the lower slide through a bearing, and the middle part is installed on the upper slide through a swivel pair. The upper slide and the lower slide are guided by the first guide component and move up and down synchronously. In other words, the upper slide always provides auxiliary support to the middle part of the support shaft, so that the support shaft has relatively good static stiffness and dynamic stiffness. At the same time, an upper bellows is provided between the upper slide and the lower furnace mouth of the process chamber to increase the dynamic seal between the support shaft and the lower furnace mouth by one level of static seal, thereby having relatively good sealing ability. And because the upper slide and the lower slide, and the first guide component that provides guidance for the upper slide and the lower slide are located outside the process chamber, they are less affected by the process temperature in the process chamber, so that relatively good lubrication can be provided, and better working reliability can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the front view of the crucible support shaft device in one embodiment.

[0019] Figure 2 It is a schematic diagram of the main cross-sectional structure of the crucible support shaft device in one embodiment.

[0020] Figure 3 for Figure 2 A magnified view of part I.

[0021] In the figure: 1. base, 2. first synchronous belt mechanism, 3. lifting screw, 4. first motor, 5. bracket, 6. first lifting slide, 7. lifting guide rail, 8. second lifting slide, 9. upper bellows, 10. crucible support, 11. guide wheel assembly, 12. turntable, 13. upper follower seat, 14. support shaft, 15. lower bellows, 16. lower follower seat, 17. second motor, 18. second synchronous belt mechanism, 19. slewing bearing, 20. flange, 21. connecting rod, 22. adjusting screw, 23. locking nut. DETAILED DESCRIPTION

[0022] exist Figure 1 In the illustrated structure, except for the crucible holder 10 and part of the support shaft 14 which can enter and exit the process chamber in the working state, the rest of the parts are located outside the process chamber. In addition, it should be known that even in the process chamber of semiconductor process equipment, in order to obtain a stable temperature field, it is necessary to select a relatively stable temperature field area in the process chamber as the reaction zone. The reaction zone is often left at a given distance from the lower furnace mouth of the process chamber. In other words, for Figure 1 The upper follower seat 13 and the lower follower seat 16 shown in the figure are all located outside the process chamber, and are even located outside the reaction zone. Since the reaction zone is relatively high in the process chamber, the formation conditions of thermal convection are mainly utilized in reverse to construct a reaction zone with a relatively stable temperature field.

[0023] It should be further known that the typical characteristic of thermal convection is that if the heating device is located at the lower side, the hot gas will move upward due to the lower heat and the upper cold and the relatively small density of the hot gas, while the cold gas will move downward due to the relatively large density of the cold gas. This is the property of thermal convection. In the field of semiconductor technology, heating is often performed in the middle and upper part of the furnace cavity, resulting in a phenomenon in which the temperature in the middle and upper part is high and the temperature in the lower part is low, that is, the hot gas is originally in the upper part and the cold gas is originally in the lower part, so the thermal convection is suppressed, so that the temperature in the lower part of the furnace cavity is relatively low, which is conducive to sealing and ensuring that the support shaft 14 works relatively stably at this location.

[0024] Regardless of whether it is constructed as a vacuum chamber, the chamber of the current semiconductor process equipment is generally a rotating body structure, and has a certain axial direction. Under the condition that the axial direction is determined, its basic reference system is determined. In addition, the crucible support shaft guide device based on the embodiment of the present invention is suitable for vertical semiconductor process equipment, and has a certain up and down.

[0025] It should be noted that even a vacuum chamber does not mean that there is a vacuum environment inside it. In more applications, the chamber is often evacuated first and then the reaction gas or protective gas is introduced. Therefore, there is often still a certain amount of gas in the chamber, which is irrelevant to the concept of the present invention and will not be described in detail here. However, even if there is reaction gas, the heat convection is suppressed in the lower part of the chamber, and the thermal impact on the support shaft 14 is relatively weak.

[0026] In addition, except for applications with relatively high vacuum degree, the vacuum chamber does not have high requirements for sealing. At the same time, it should be known that for vacuum, the lowest vacuum degree is only minus one atmosphere relative to the standard atmospheric pressure of 0. It should be known that the industrial use of atmospheric pressures of dozens or hundreds (for example, low pressure refers to 0.7MPa~1.0MPa, medium pressure refers to 1.MPa0~10MPa, high pressure refers to 10~100MPa, and 1MPa is generally equivalent to 10 atmospheres) has a very strong sealing ability that can be achieved in industry, and will not be repeated here. It is relatively easy to achieve a seal with a minimum pressure of minus one atmosphere.

[0027] As mentioned above, in the embodiment of the present invention, except for the crucible support 19 and the support shaft 14, the rest of the crucible support support shaft device is located outside the process chamber, so it is less affected by the process temperature in the process chamber as a whole. Figure 1 The guide wheel assembly 11, turntable 12, and upper follower seat 13 shown in the figure can make the upper sealed chamber constructed by the upper bellows 9 communicate with the process chamber due to the cooperation between the crucible support 10 and the lower furnace cover of the process chamber. However, since heat convection is suppressed, and the upper sealed chamber constructed by the bellows 9 is located below the process chamber, especially below the reaction zone, under the condition that heat convection is effectively suppressed, heat radiation is also shielded by the crucible support 10. Therefore, for example, the guide wheel assembly 11 shown in the figure can provide guidance for the support shaft 14 by means of rolling friction.

[0028] exist Figure 1 and Figure 2 In the illustrated structure, most of a crucible support shaft device is located outside the process chamber, and the figure adopts a configuration in which, for example, the bracket 5 is configured on one side of the support shaft 14. In some implementations, the bracket 5 can also be configured in a gantry or in an axisymmetric or plane-symmetrical manner on both sides of the support shaft 14. Figure 1 and Figure 2 The structure shown in is relatively compact as a whole, and adopts a gantry method to provide support for the upper follower seat 13 from both sides. The reliability of the support is relatively high, that is, the support at both ends is not easily affected by bending and the like relative to the overhang, which is common knowledge in the mechanical field and will not be elaborated here.

[0029] Figure 1 and Figure 2 The bracket 5 is a vertical bracket, which not only serves as the base of the crucible support shaft device, but also can serve as the installation base of the furnace body, so that the support shaft 14 and the furnace body have the same installation base, which is conducive to maintaining relatively good coaxiality between the two.

[0030] Figure 1A lifting guide rail 7 serving as a first guide component is provided in the middle. In addition to using, for example, a T-shaped guide rail, a rectangular guide rail, a dovetail guide rail, etc., as the first guide component, a guide component such as a vertically arranged guide rod can also be used.

[0031] The first guide component mainly provides relatively reliable guidance to ensure that the support shaft 14 and the furnace body maintain relatively good coaxiality.

[0032] The upper slide and the lower slide are Figure 1 and Figure 2 The upper slide includes the second lifting slide 8 shown in the figure and the upper follower seat 13 fixedly mounted on the second lifting slide 8. Relatively speaking, an upper lifting sliding pair is formed between the second lifting slide 8 and the lifting guide rail 7, and the upper follower seat 13 is carried on the second lifting slide 8.

[0033] It can be clearly seen from the figure that the second lifting slide 8 has a reinforcing plate, and the reinforcing plate is arranged on the side of the second lifting slide 8 facing the support shaft 14 to ensure that it has relatively high rigidity and keeps the axis of the support shaft 14 vertical.

[0034] Likewise, Figure 1 and Figure 2 The middle lower slide seat is also an assembly, and includes the first lifting slide seat 6 shown in the figure and the lower follower seat 16 carried on the first lifting slide seat 6. Similarly, it can be clearly seen from the figure that the first lifting slide seat 6 is also strengthened to improve the overall static rigidity, so that the axis of the support shaft 14 remains vertical.

[0035] The upper follower seat 13 has a seat hole, which is a bearing seat hole specifically used in the mechanical field for installing bearings. Figure 2 and Figure 3 In the illustrated structure, a slewing bearing 18 is installed in the seat hole, and then the inner ring of the slewing bearing 18 is sleeved on the inner ring of the support shaft 14, and the inner rings are circumferentially connected, so that the axial direction can maintain vertical freedom.

[0036] exist Figure 2 and Figure 3 In the illustrated structure, the support shaft 14 is not directly mounted on the slewing bearing 18, but is installed through the turntable 12. This is mainly because the cooperation between the support shaft 14 and the slewing bearing 18 alone is difficult to form a circumferential connection and axial guide, although in some implementations, the inner ring of the slewing bearing 18 may have a sliding key, that is, a keyed bearing.

[0037] Relatively speaking, the turntable 12 is provided with a journal, and the turntable 12 is installed on the upper follower seat 13 through the cooperation of the journal and the slewing bearing 18, and the turntable 12 is provided with a center hole, and the center hole and the support shaft 14 are easy to construct an axially guided circumferentially connected structure.

[0038] It should be noted that, in the preferred embodiment, there are an upper bellows 9 and a lower bellows 15 as shown in the figure. The purpose of configuring the two bellows is to provide a dynamic seal, wherein the purpose of the lower bellows 15 is to guide the support shaft 14 to the center hole of the turntable 12. At the same time, considering that the slewing bearing 18 also has a gap, although a covered bearing can be used to reduce the problem of poor air tightness, due to the existence of the dynamic seal, the lower bellows 15 can be used to construct a first-level static seal outside the dynamic seal, thereby improving the sealing ability.

[0039] The upper end of the upper bellows 9 is mounted at the lower furnace opening of the furnace body by means of a flange connection, and the lower end of the upper bellows 9 is mounted on the upper follower plate 13 by means of a flange connection.

[0040] In some implementations, the connection between the upper bellows 9 and the upper follower plate 13 may also be other forms of connection, especially quick connection, to facilitate the removal and placement of workpieces.

[0041] One way of quick connection is press-fitting in form-locking, where the flange is replaced with a flange, and the protruding part of the flange is buckled with a manual lock to facilitate quick disassembly and assembly.

[0042] A more common lock is a radially movable spring lock, which is actually a spring pin. The lower surface of the spring pin body is wedge-shaped, and the pin body can be pressed on the upper surface of the flange by utilizing the inclined wedge principle to achieve rapid locking.

[0043] Obviously, the upper bellows 9 should maintain relatively good coaxiality with the support shaft 14 , and under ideal conditions, the axis of the upper bellows 9 is collinear with the axis of the support shaft 14 .

[0044] Similarly, the assembly method of the lower bellows 15 can refer to the aforementioned description of the upper bellows 9. At the same time, the difference is that the lower bellows 15 does not need to consider the quick disassembly performance. Therefore, the lower bellows 15 is mainly connected to the upper follower seat 13 and the lower follower seat 16 by flange connection. Obviously, under ideal conditions, the lower bellows 15 should be colinear with the support shaft 14.

[0045] Figure 1 and Figure 2 In the embodiment, the crucible holder 10 only needs to deliver the crucible to the predetermined position of the reaction zone, and the support shaft 14 is located below the crucible holder 10, which is relatively farther from the reaction zone. As mentioned above, due to the suppression of heat convection and the shielding of the crucible holder 10, the heat radiation received by the support shaft 14 is relatively small. As for heat conduction, since the crucible holder 10 is mostly made of materials with relatively low thermal conductivity, the heat effect on the support shaft 14 is relatively small. Therefore, in the embodiment of the present invention, the support shaft 14 can be adapted to a guide assembly, such as the guide wheel assembly 11 shown in the figure.

[0046] The support shaft 14 extends upward from the center hole and is cantilevered. Under most conditions of use, the guide wheel assembly 11 shown in the figure basically does not move. It only needs to move when the support shaft 14 and the upper follower seat 13 produce relative movement in the up and down directions. That is, the guide wheel assembly 11 does not move frequently, and the reliability requirements for it are relatively low.

[0047] In addition, the guide wheel assembly 11 is installed on the upper follower seat 13 through an elongated hole, and the extension direction of the elongated hole is the radial direction of the upper follower seat 13, so that the gap between the guide wheel assembly 11 and the support shaft 14 can be adjusted. Here, the guide wheel assembly 11 is more to adjust the vertical state of the support shaft 14 under the condition of insufficient support stiffness of the two slide seats through the pre-compression of the guide wheel assembly 11 located at different orientations.

[0048] Regarding the installation of the support shaft 14, its lower end is installed on the lower follower seat 16 through a bearing, and the shaft head is exposed at the lower end. The second driven wheel is installed on the shaft head, and then the second synchronous belt mechanism 18 is used to drive the support shaft 14 to rotate.

[0049] Accordingly, if Figure 1 The second synchronous belt mechanism 18 used as the second driving device is installed on the lower follower seat 16.

[0050] The lifting and lowering of the support shaft 14 is realized by using a first driving device. First, the two slides are guided on, for example, the lifting guide rail 7 and driven by, for example, a screw nut mechanism. Accordingly, if the two slides are separate, they can be respectively equipped with screw nuts. If they are integrated, only one screw nut can be equipped.

[0051] It should be noted that the fact that one lead screw nut can be provided does not mean that only one can be provided.

[0052] In addition, if Figure 1 The upper and lower ends of the lifting screw 3 are mounted on the bracket 5 through bearings.

[0053] exist Figures 1 to 3 In the illustrated structure, the upper slide and the lower slide are connected as one at the first lifting slide 6 and the second lifting slide 8 shown in the figure. This integration is only used to indicate that the two are connected to form an assembly, but does not mean that the distance between the two cannot change.

[0054] Furthermore, the distance between the upper follower seat 13 and the lower follower seat 16 can be adjusted according to different process requirements. Therefore, the connecting component adopts an adjustable device. Correspondingly, a lower bellows 15 is provided between the upper slide seat and the lower slide seat, and the lower bellows 15 is coaxial with the support shaft to construct a lower sealing chamber.

[0055] exist Figure 3In the illustrated structure, one example of the connecting component includes: A connecting rod 21, the upper end of which is connected to the upper slide seat; An adjusting screw 22, the adjusting screw 22 is connected to the lower end of the connecting rod 21, and forms an integral rod with the connecting rod 21; A coupling hole is formed on the lower sliding seat to cooperate with the screw rod; The locking nut 23 is screwed together with the adjusting screw 22 to lock the adjusting screw 22 after it is adjusted into place.

[0056] Regarding the direct fit between the connecting rod 21 and the upper slide seat, it is obvious that the connection should have rotational freedom. Therefore, the connecting rod 21 and the upper slide seat can be connected by a cylindrical hinge or a ball hinge. The construction methods are common knowledge in the mechanical field and will not be described here. One of the simplest construction methods is to open a light hole on the upper slide seat, and set a shaft ring at the upper end of the connecting rod 21. The diameter of the shaft ring is larger than the diameter of the light hole. The upward part of the shaft ring also has a shaft section, which can be inserted into the light hole, and the light holes are slidably matched, that is, a simple cylindrical hinge structure is formed.

Claims

1. A crucible support shaft device, characterized in that: include: The bracket is a vertical bracket and is provided with a first guide component in the vertical direction; An upper slide seat is guided by the first guide component and is provided with a seat hole; A turntable, mounted in the seat hole through a bearing and having a center hole; A supporting shaft, extending upward through the central hole, for supporting the crucible support; A lower sliding seat is guided by the first guide member, and the lower end of the support shaft is mounted on the lower sliding seat through a swivel pair; A first driving device, mounted on the bracket, to drive the upper slide and the lower slide to move on the first guide member; as well as A second driving device is mounted on the lower slide seat to drive the support shaft to rotate; The upper bellows has an upper end for connecting with the lower furnace port of the process chamber, and a lower end connected with the upper slide seat and coaxial with the support shaft.

2. The crucible support shaft device according to claim 1, characterized in that: The upper slide seat and the lower slide seat are connected as a whole via a connecting component; The connecting member is an adjustable device for adjusting the distance between the upper slide seat and the lower slide seat; Correspondingly, a lower bellows is provided between the upper slide seat and the lower slide seat, and the lower bellows is coaxial with the support shaft.

3. The crucible support shaft device according to claim 2, characterized in that: The connecting component comprises: A connecting rod, the upper end of which is connected to the upper slide seat; A screw rod is connected to the lower end of the connecting rod to form an integrated rod; A coupling hole is formed on the lower sliding seat to cooperate with the screw rod; The locking nut is screwed together with the screw rod to lock the screw rod after it is adjusted into place.

4. The crucible support shaft device according to claim 3, characterized in that: The upper end of the connecting rod is a cylindrical hinge head or a ball hinge head; Correspondingly, the upper sliding seat is provided with a cylindrical hinge hole or a ball hinge socket.

5. The crucible support shaft device according to any one of claims 1 to 4, characterized in that: The first driving device comprises a nut-screw mechanism; Correspondingly, the screw of the nut-screw mechanism is mounted on the bracket via a bearing; The screw nut of the screw nut mechanism is installed on the lower slide seat through a bearing; The upper slide seat and the lower slide seat are linked to each other.

6. The crucible support shaft device according to claim 5, characterized in that: The first driving device further comprises a first synchronous belt mechanism driven by a first motor; Correspondingly, the first synchronous belt mechanism is used to drive the lead screw.

7. The crucible support shaft device according to claim 1, characterized in that: The second driving device is a second synchronous belt mechanism; a second driven pulley is correspondingly installed at the lower end of the support shaft.

8. The crucible support shaft device according to claim 1, characterized in that: The bracket is located on one side of the support shaft, and the first guide component is a linear guide rail installed on the bracket; Correspondingly, the upper slide seat and the lower slide seat are arranged on the linear guide rail in a cantilevered manner.

9. The crucible support shaft device according to claim 1, characterized in that: The connection between the upper bellows, the lower furnace port and the upper slide seat is a flange connection.

10. The crucible support shaft device according to claim 1, characterized in that: The upper surface of the rotating disk is provided with a plurality of roller assemblies, which are evenly arranged around the supporting shaft to provide sliding guidance for the supporting shaft; Correspondingly, the assembly hole of the rotating disk for mounting the roller assembly is a radially arranged elongated hole.

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