CN116180227A

CN116180227A - Pulling shaft of single crystal furnace, pulling device, single crystal furnace and crystal pulling method

Info

Publication number: CN116180227A
Application number: CN202211105332.7A
Authority: CN
Inventors: 曹建伟; 朱亮; 傅林坚; 叶钢飞; 阮文星; 梁晋辉
Original assignee: Zhejiang Jingsheng Mechanical and Electrical Co Ltd
Current assignee: Zhejiang Jingsheng Mechanical and Electrical Co Ltd
Priority date: 2022-09-09
Filing date: 2022-09-09
Publication date: 2023-05-30

Abstract

The application relates to the field of semiconductor growth, in particular to a pulling shaft of a single crystal furnace, which is applied to the single crystal furnace and comprises the following components: the hard shaft is in a long and straight state and is vertically arranged; the first end of the flexible shaft is connected to the bottom of the hard shaft, and the flexible shaft and the hard shaft are coaxially arranged; and the clamp assembly is connected to the second end of the flexible shaft and used for clamping seed crystals. Solves the technical problem of low crystal pulling quality and achieves the technical effect of improving the crystal quality.

Description

Pulling shaft of single crystal furnace, pulling device, single crystal furnace and crystal pulling method

Technical Field

The application relates to the field of semiconductor growth, in particular to a pulling shaft of a single crystal furnace, a pulling device, the single crystal furnace and a crystal pulling method.

Background

The Czochralski silicon growth furnace is the main equipment for preparing the silicon single crystal material, and is also called a silicon single crystal growth furnace or a single crystal furnace. The equipment melts the high-purity polysilicon raw material in the quartz crucible in a graphite heating mode, and under the protection of continuous low-pressure argon, silicon crystals are crystallized into a single crystal on a tiny seed crystal in a way of getting out of the way under proper temperature and growth speed. With the demand of market development, silicon single crystal size is moving toward large-size, heavy-weight trends.

In the prior art, a seed crystal is generally connected through a flexible shaft, and the seed crystal and a silicon liquid level are gradually pulled upwards and grown, so that the crystal rod is obtained, and the flexible shaft has certain flexibility, so that the crystal is shaken to different degrees due to vibration or mechanical errors in the crystal pulling process, the crystal shaking refers to the motion state of a single pendulum or a conical pendulum of the crystal in the drawing process, and the quality of the crystal obtained by drawing is low.

Therefore, the technical problems of the prior art are: the crystal pulling quality is not high.

Disclosure of Invention

The application provides a pulling shaft of a single crystal furnace, a pulling device, the single crystal furnace and a crystal pulling method, which solve the technical problem of low crystal pulling quality and achieve the technical effect of improving the crystal quality.

In a first aspect, the present application provides a single crystal growing furnace's lift axle, adopts following technical scheme:

a pulling shaft of a single crystal furnace, which is applied to the single crystal furnace, comprising: the hard shaft is in a long and straight state and is vertically arranged; the first end of the flexible shaft is connected to the bottom of the hard shaft, and the flexible shaft and the hard shaft are coaxially arranged; and the clamp assembly is connected to the second end of the flexible shaft and used for clamping seed crystals.

Preferably, the hard shaft includes: an outer shaft, wherein an inner cavity penetrating up and down is formed in the outer shaft; the inner shaft is positioned in the inner cavity of the outer shaft, the inner shaft and the outer shaft are coaxially arranged, the inner shaft and the outer shaft have mutually independent vertical movement degrees of freedom, and the inner shaft and the outer shaft have synchronous rotation degrees of freedom around the shaft; wherein the first end of the flexible shaft is connected to the bottom of the inner shaft.

Preferably, a partition is arranged at the bottom of the inner cavity of the outer shaft, and the partition is fixedly connected to the bottom of the outer shaft or is integrally formed with the outer shaft; the first end of the flexible shaft penetrates through the partition plate from bottom to top, and the first end of the flexible shaft is fixed in the inner cavity of the outer shaft.

Preferably, the two ends of the flexible shaft are provided with first limiting parts; the flexible shaft is provided with coupling assembling respectively on the both ends of flexible axle, the flexible axle through two sets of coupling assembling respectively with hard axle with anchor clamps subassembly is connected, every group coupling assembling includes: the sleeve is used for being connected with the inner shaft or the clamp assembly, a channel which is arranged along a first direction and penetrates through the sleeve is formed in the side wall of the sleeve, the channel can accommodate the flexible shaft to enter the sleeve, and the first limiting part of the flexible shaft is in contact with the end part of the sleeve to limit the position. Preferably, the partition plate is provided with a concave part which is concave towards the inner cavity of the outer shaft; the top of the clamp assembly is provided with a protruding portion which is consistent with the recessed portion, and the protruding portion is formed with a first station and a second station along with the lifting of the inner shaft and the recessed portion: when the bulge is at the first station, the flexible shaft extends out of the outer shaft, and the bulge part and the concave part are separated from each other; when the bulge is at the second station, the flexible shaft retracts into the outer shaft, and the bulge and the concave part are in mutual interference fit.

Preferably, the jig assembly includes: the balancing weight is connected with the flexible shaft; and the clamp is connected to the bottom of the balancing weight and is used for connecting seed crystals.

In a second aspect, the present application provides a single crystal furnace pulling apparatus, which adopts the following technical scheme:

a pulling apparatus for a single crystal furnace, applied to the single crystal furnace, comprising: the lifting shaft is the lifting shaft; the driving mechanism is connected with and acts on the lifting shaft and is used for driving the lifting shaft to rotate and lift.

Preferably, the driving mechanism includes; the pedestal, the pedestal includes: a first seat, the first seat being fixed; a second seat; the second seat is movably connected to the second seat, and the second seat has a moving degree of freedom for vertical movement; the first driving assembly is connected to the second seat and acts on the outer shaft to drive the outer shaft to rotate, so that the inner shaft and the outer shaft are driven to rotate synchronously; and a second drive assembly, the second drive assembly comprising: the first driving piece is connected to the first seat and acts on the outer shaft to drive the lifting shaft to lift; the second driving piece is connected to the second seat and acts on the inner shaft to drive the inner shaft to independently lift.

In a third aspect, the present application provides a single crystal furnace, which adopts the following technical scheme:

a single crystal furnace, comprising: a single crystal furnace body; the pulling device is the pulling device, and is located at the top of the single crystal furnace body and used for vertically downwards entering the single crystal furnace body to pull the crystal.

In a fourth aspect, the present application provides a crystal pulling method of a single crystal furnace, which adopts the following technical scheme:

a crystal pulling method using the pulling device comprises the following steps: the seed crystal on the clamp contacts the silicon liquid surface; the pulling shaft is driven by the driving mechanism to rotate and is pulled upwards to obtain the crystal bar.

Preferably, the whole lifting shaft is driven to descend into the single crystal furnace body, and the seed crystal is contacted with the silicon liquid surface; driving the lifting shaft to rotate and lift, and forming fine crystals on the seed crystal; the inner shaft is driven to ascend relative to the outer shaft, and the flexible shaft is driven to retract into the inner cavity of the outer shaft so as to reduce the extension length of the flexible shaft; and (5) completing the pulling growth of the crystal bar.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the utility model provides a novel lifting shaft, which is characterized in that the bottom end of a hard shaft is connected with a flexible shaft, the hard shaft has rigidity, the length of the flexible shaft is reduced compared with the traditional long flexible shaft lifting scheme, and the crystal shaking amplitude formed by the flexible shaft can be effectively controlled; therefore, the method reduces the amplitude of crystal shaking, solves the technical problem of low crystal pulling quality, and achieves the technical effect of improving the crystal quality.

2. Because the flexible shaft has flexibility, the vertical state is kept under the action of the crystal bar, the eccentric error of the hard shaft is reduced, the whole concentricity of the lifting shaft is improved, the technical problem of low crystal pulling quality is solved, and the technical effect of improving the crystal quality is achieved.

3. The hard shaft is divided into an outer shaft and an inner shaft which are respectively lifted, and the crystal bar shaking generated by the single pendulum effect of the flexible shaft is slowed down by adjusting the extending length of the flexible shaft, so that the quality of the crystal bar is further improved.

Drawings

FIG. 1 is a schematic view of a lift shaft as described herein;

FIG. 2 is a front cross-sectional view of the lift shaft described herein;

FIG. 3 is a schematic view of a connection assembly of the lift shaft described herein;

FIG. 4 is a schematic flow chart of a crystal pulling process as described herein;

FIG. 5 is a schematic drawing of a pulling process flow of the crystal pulling method described herein.

Reference numerals illustrate: 100. a hard shaft; 110. an inner shaft; 120. an outer shaft; 121. a partition plate; 122. a recessed portion; 200. a flexible shaft; 210. a first limit part; 220. a connection assembly; 221. a sleeve; 222. a channel; 223. a second limit part; 300. a clamp assembly; 310. balancing weight; 311. a boss; 320. and (3) clamping.

Detailed Description

The numbering of the components itself, e.g. "first", "second", etc., is used herein merely to distinguish between the described objects and does not have any sequential or technical meaning. The terms "coupled" and "connected," as used herein, are intended to encompass both direct and indirect coupling (coupling), unless otherwise indicated. In the description of the present application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," etc. indicate or refer to an orientation or positional relationship based on that shown in the drawings, merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

In this application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

The embodiment of the application provides a pulling shaft of a single crystal furnace, a pulling device, the single crystal furnace and a crystal pulling method, which solve the technical problem of low crystal pulling quality and achieve the technical effect of improving the crystal quality.

In order to better understand the above technical solutions, the following detailed description will refer to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

Along with the market development demand, the silicon single crystal size is moving towards large size and heavy weight, and the crystal quality is also required to be ensured; in the actual research and development process, the applicant adopts the flexible shaft 200 to pull crystal due to the compact structure and strong applicability of the flexible shaft 200 growth furnace, but the single crystal furnace using the flexible shaft 200 also has some problems: firstly, due to the limitation of a winding mechanism of the flexible shaft 200, the flexibility of a tungsten alloy cable needs to be ensured, so that the bearing capacity of the flexible shaft 200 is further limited, and the capacity improvement of a single device is limited; secondly, the flexible shaft 200 is adopted for lifting, a periodic shaking zone exists under the action of a simple pendulum mechanism under a certain length of the flexible shaft 200, and the shaking amplitude of crystals is gradually increased along with the increase of the rotating speed of the crystals, so that a process window for growing the crystals with higher quality is limited; thirdly, the flexible shaft 200 can only concentrically grow crystals, the rotation speed of the center point of the crystal interface is 0, and a defect source is easy to form; fourthly, the tungsten alloy cable gradually gets away from the high temperature area along with the increase of the length of the single crystal, and the temperature of the tungsten alloy cable gradually decreases to generate volume shrinkage, so that the lifting speed V of the position of a crystal growth interface is not exactly equal to the set lifting speed, and the deviation of V enables a defect process window to be accurately controlled to be smaller; as such, some of the problems associated with the flexible shaft 200 during the pulling process are in need of resolution.

The application provides a pulling shaft of a single crystal furnace, which is applied to the single crystal furnace, wherein the pulling shaft is used for downwards entering the single crystal furnace, as shown in fig. 1, pulling is carried out through seed crystals connected with the bottom of the pulling shaft, the pulling shaft is vertically arranged, the pulling shaft sequentially comprises a hard shaft 100, a flexible shaft 200 and a clamp assembly 300 from top to bottom, and the hard shaft 100 is used as a connecting foundation of the flexible shaft 200; flexible shaft 200 is used as a connection base for clamp assembly 300; the clamp assembly 300 is used to clamp a seed crystal.

Hard shaft 100 as shown in fig. 1, hard shaft 100 is used as a connection base for flexible shaft 200. The hard shaft 100 is located right above the flexible shaft 200, and the hard shaft 100 is in a long straight cylindrical shape and is arranged in a vertical state.

Further, as shown in fig. 2, the hard shaft 100 includes an outer shaft 120 and an inner shaft 110, the outer shaft 120 is tubular, an inner cavity is formed in the outer shaft 120, and the inner cavity penetrates the outer shaft 120 up and down; the inner shaft 110 is accommodated in the inner cavity, the inner shaft 110 and the outer shaft 120 are coaxially arranged, the inner shaft 110 and the outer shaft 120 have mutually independent movement degrees of freedom, the inner shaft 110 and the outer shaft 120 have synchronously rotatable rotation degrees of freedom, and in particular, the inner shaft 110 and the outer shaft 120 can relatively move, namely, the inner shaft 110 can independently and vertically lift relative to the outer shaft 120, in other words, the outer shaft 120 can also independently and vertically lift relative to the inner shaft 110; and a synchronous structure is arranged between the inner shaft 110 and the outer shaft 120, so that the outer shaft 120 rotates around the shaft and can drive the inner shaft 110 to synchronously rotate, in one embodiment, the inner shaft 110 is provided with a section of square rod area, the cross section of the inner shaft 110 in the square rod area is square, correspondingly, the inner wall of the outer shaft 120 is provided with a section of square cavity, the inner ring of the cross section of the square cavity is square corresponding to the square rod area, and the square rod area is matched with the square cavity, so that the inner shaft 110 can rotate the same as the outer shaft 120 through the synchronous structure while the outer shaft 120 rotates, and independent lifting actions of the inner shaft 110 and the outer shaft 120 are not influenced.

Still further, as shown in fig. 1, a partition 121 is coupled to the bottom of the outer shaft 120, and the partition 121 serves to close the bottom end of the outer shaft 120 to improve heat insulation protection of the inner structure of the outer shaft 120, and in one embodiment, the partition 121 is fixedly coupled to the bottom end of the outer shaft 120 such that the bottom end of the outer shaft 120 is closed by the partition 121; in other embodiments, the septum 121 is integrally formed with the bottom end of the outer shaft 120, also such that the bottom end of the outer shaft 120 is closed by the septum 121; the partition 121 is provided with a through hole for penetrating the flexible shaft 200, and it should be noted that the through hole is located on the rotation center of the hard shaft 100.

Flexible shaft 200, as shown in fig. 2 and 3, flexible shaft 200 is used as a connection base for clamp assembly 300. The first end of the flexible shaft 200 is connected to the hard shaft 100, the second end of the flexible shaft 200 is connected to the fixture assembly 300, specifically, the first end of the flexible shaft 200 is connected to the bottom of the hard shaft 100, and the flexible shaft 200 and the hard shaft 100 are coaxially arranged, so that the problem of crystal quality degradation caused by different crystals in the crystal pulling process is solved; in one embodiment, when the hard shaft 100 is in a cylindrical shape with a long and straight body, the flexible shaft 200 is directly connected to the bottom of the hard shaft 100; in other embodiments, when the hard shaft 100 includes the inner shaft 110 and the outer shaft 120 that can be lifted and rotated independently and synchronously, the flexible shaft 200 is connected to the bottom end of the inner shaft 110, and in particular, the flexible shaft 200 is connected to the clamping mechanism by passing through a hole in the partition 121 from one end connected to the bottom end of the inner shaft 110. Flexible shaft 200 has some flexibility and in one embodiment flexible shaft 200 is a tungsten wire rope.

The clamp assembly 300, as shown in fig. 2 and 3, the clamp assembly 300 is used to clamp a seed crystal. The clamping mechanism is connected to the second end of the flexible shaft 200, namely to the bottom of the flexible shaft 200, and comprises a balancing weight 310 and a clamp 320, wherein the balancing weight 310 is used for balancing the flexible shaft 200 and simultaneously serves as a connecting foundation of the clamp 320; the clamp 320 is used for clamping seed crystals; the balancing weight 310 is connected to the bottom end of the flexible shaft 200, and the clamp 320 is connected to the balancing weight 310, wherein the balancing weight 310 and the clamp 320 are arranged in a central symmetry manner and are all coaxially arranged with the hard shaft 100; in one embodiment, the clamp 320 specifically employs a graphite chuck to hold a seed crystal.

Further, as shown in fig. 2 and 3, the two ends of the flexible shaft 200 are respectively provided with a first limiting portion 210, and the first limiting portion 210 is larger than the flexible shaft 200, and in one embodiment, the first limiting portion 210 is a limiting ball connected to the two ends of the flexible shaft 200; further, a connection assembly 220 is provided on the flexible shaft 200, specifically, the connection assembly 220 has two groups, and the two groups of connection mechanisms are respectively provided at two ends of the flexible shaft 200, that is, two ends of the flexible shaft 200 are respectively used for connecting the flexible shaft 200 with the inner shaft 110 and the clamp assembly 300 through the connection assembly 220; the two sets of connection assemblies 220 have the same structure, in this embodiment, only one set of connection assemblies 220 is described as an example, the connection assemblies 220 include a sleeve 221, the sleeve 221 is hollow and penetrates through two ends of the sleeve 221, a channel 222 is formed on a side wall of the sleeve 221, the channel 222 is arranged along a first direction, specifically, a direction of the channel 222 is parallel to an axial direction of the sleeve 221, an inner space of the sleeve 221 is communicated with an outer space through the channel 222, and the channel 222 is formed on a side wall of the sleeve 221 and penetrates through two ends of the sleeve 221 in a length direction; further, a second limiting portion 223 is provided at one end of the sleeve 221, so that the flexible shaft 200 enters the sleeve 221 through the channel 222, and the first limiting portion 210 of the flexible shaft 200 is in interference fit with the second limiting portion 223 at the end of the sleeve 221, so that the flexible shaft 200 forms a limit, and the lifting shaft forms a pure hard shaft for lifting. In the connection assembly 220 at the upper end of the flexible shaft 200, a corresponding sleeve 221 is fixedly connected to the bottom end of the inner shaft 110; in the connecting assembly 220 at the lower end of the flexible shaft 200, the corresponding sleeve 221 is fixedly connected to the top of the clamping mechanism, specifically, the corresponding sleeve 221 is fixedly connected to the top of the balancing weight 310, so that the flexible shaft 200 is respectively connected with the hard shaft 100 and the clamp assembly 300.

Still further, as shown in fig. 2 and 3, the bottom of the inner shaft 110 has a transition section at one end, the transition section is connected with the flexible shaft 200 through a connection assembly 220 at the top of the flexible shaft 200, specifically, a sleeve 221 of the connection assembly 220 is connected to the bottom of the transition section, and a cavity is formed in the transition section, so that the flexible shaft 200 has a space for moving upwards; correspondingly, the balancing weight 310 is connected with the flexible shaft 200 through the connecting component 220, specifically, the sleeve 221 of the connecting component 220 is connected to the top of the balancing weight 310, and a cavity is formed in the balancing weight 310, so that the flexible shaft 200 has a section of space for downward movement.

As shown in fig. 2 and 3, specifically, the matching structure is disposed at the bottom of the outer shaft 120 and the top of the balancing weight 310, the matching structure includes a concave portion 122 and a convex portion 311, the concave portion 122 is disposed below the partition plate 121 at the bottom of the outer shaft 120, and a chamfer is formed inwards to enable the bottom of the outer shaft 120 to form an inwards concave portion 122; the protruding portion 311 is disposed at the top of the balancing weight 310, and a chamfer is formed at the top edge of the balancing weight 310 to form an protruding portion 311 protruding outwards at the top of the balancing weight 310, which is worth noting that the recessed portion 122 and the protruding portion 311 are mutually matched, in other words, the shape and the size of the inward recess of the recessed portion 122 are consistent with the shape and the size of the outside of the protruding portion 311, so that the protruding portion 311 at the top of the balancing weight 310 can be just accommodated in the recessed portion 122; the protruding portion 311 is formed with the first and second stations with the inner shaft 110 up and down and the recessed portion 122: in the first station, the flexible shaft 200 extends out of the outer shaft 120, and the protruding part 311 and the recessed part 122 are separated from each other; in the second station, the flexible shaft 200 is retracted into the outer shaft 120, and the protruding portion 311 is in interference fit with the recessed portion 122; specifically, by driving the inner shaft 110 upward, the flexible shaft 200 is driven to retract into the inner cavity of the outer shaft 120, and at this time, the clamp assembly 300 is pulled by the flexible shaft 200 to synchronously move upward, so that the protruding portion 311 enters the recessed portion 122 to form a fit, and thus the clamp assembly 300 and the hard shaft 100 are integrated, so as to reduce crystal shaking.

The application also provides a pulling device of the single crystal furnace, which is applied to the single crystal furnace and is used for enabling a pulling shaft to downwards enter the single crystal furnace and pulling crystal through seed crystals connected with the bottom of the pulling shaft, wherein the pulling device comprises the pulling shaft and a driving mechanism, the pulling shaft is positioned right above the single crystal furnace and is vertically arranged and is used for downwards entering the single crystal furnace and pulling crystal; the driving mechanism is used for driving the lifting shaft to rotate and lift.

And the pulling shaft is used for pulling downwards into the single crystal furnace as shown in figures 1-4. The lifting shaft is arranged at the top of the single crystal furnace, is vertically arranged, and has the same specific structure as the lifting shaft, and is not tired here.

And the driving mechanism is not shown and is used for driving the lifting shaft to rotate and lift. The driving mechanism is positioned at the top of the single crystal furnace, acts on the lifting shaft and drives the lifting shaft. The driving mechanism comprises a base body, a first driving assembly and a second driving assembly, wherein the base body is used as an installation bearing foundation of the first driving assembly and the second driving assembly; the first driving component is used for driving the lifting shaft to rotate; the second driving component is used for driving the lifting shaft to lift.

The base body is used as an installation bearing foundation of the first driving assembly and the second driving assembly. The base body comprises a first base and a second base, the first base is relatively fixed, and the first base is fixedly arranged right above the single crystal furnace through the frame; the second seat is connected to the first seat in a sliding manner, and can slide vertically relative to the first seat; in one embodiment, the second seat is slidingly connected to the first seat by a vertically arranged slide rail.

The first driving assembly is used for driving the lifting shaft to rotate. The first driving component is positioned on the second seat and can be lifted along with the second seat. It should be noted that the outer shaft 120 is rotatably connected to the second seat through a bearing, so that the outer shaft 120 can be lifted and lowered along with the second seat while being rotated by the first driving assembly. Specifically, the first driving assembly includes a first motor and a first synchronous belt, the first motor is connected to the second seat, and the first synchronous belt is in transmission connection with an output shaft of the first motor and an outside of the outer shaft 120, so that the first motor can drive the outer shaft 120 to rotate.

The second driving assembly is used for driving the lifting shaft to lift. The second driving assembly comprises a first driving piece and a second driving piece, and the first driving piece is used for driving the lifting shaft to integrally lift; the second driving member is used for driving the inner shaft 110 to independently lift and lower.

The first driving piece is used for driving the lifting shaft to integrally lift. The first driving piece is connected to the first seat and comprises a screw rod, a sliding block, a second motor and a second synchronous belt, wherein the screw rod is arranged in the vertical direction and is rotationally connected to the first seat; the sliding block is connected to the screw rod through threads and is fixedly connected with the second seat; the second motor is connected to the first seat and acts on the screw rod, and in particular, a second synchronous belt is in transmission connection between the output end of the second motor and the screw rod, so that the second motor realizes the rotary driving of the screw rod; so, the second motor drives the lead screw to rotate, the sliding block slides along the direction of the lead screw, the second seat is connected to the first seat in a sliding way through the sliding rail, and the second seat and the lifting shaft are driven to integrally vertically lift under the guiding of the sliding rail.

The second driving member is used for driving the inner shaft 110 to independently lift and lower. The second driving piece is connected to the top of the lifting shaft, the second driving piece comprises a cylinder, the cylinder is connected to the second seat, the cylinder and the lifting shaft are coaxially arranged, and an output rod of the cylinder is connected to the top of the inner shaft 110 through a universal joint, so that the cylinder can drive the inner shaft 110 to lift, and the inner shaft 110 can lift independently while the lifting shaft integrally lifts.

Thus, the first driving mechanism drives the lifting shaft to rotate so as to meet the crystal rotation requirement of the crystal pulling; in the second driving mechanism, the first driving piece drives the lifting shaft to integrally lift, the first driving piece drives the lifting shaft to descend into the single crystal furnace, crystals are firstly adsorbed on seed crystals to complete fine crystal growth, the lifting shaft is driven by the first driving piece to lift upwards, crystal bars are gradually formed, the inner shaft 110 is independently driven by the second driving piece to ascend or descend relative to the outer shaft 120 when the lifting shaft integrally lifts according to technological requirements in the lifting process, so that the length of the flexible shaft 200 is adjusted, and the crystal bars are further lifted along with the first driving piece to complete crystal bar growth.

The application also provides a single crystal furnace, which is used for crystal growth, and silicon single crystal is obtained by pulling in a molten silicon material, and comprises a single crystal furnace body and a pulling device, wherein the single crystal furnace body is used as a main body for crystal growth; the lifting device is used for lifting the crystal bar.

A single crystal furnace body, not shown, which serves as a main body for crystal growth. The single crystal furnace main body comprises a main furnace chamber and an auxiliary furnace chamber, wherein the main furnace chamber is internally provided with a crucible, a heater and other structures for providing crystal growth, the auxiliary furnace chamber is connected to the top of the main furnace chamber and is communicated with the main furnace chamber, and the single crystal furnace main body is equipment for crystal bar growth of photovoltaics or semiconductors, and the structures of the equipment are not further described.

And the lifting device is used for lifting the crystal bar as shown in figures 1-4. The structure of the lifting device is the same as that of the lifting device, and the structure is not repeated here; it is worth noting that the pulling device is located at the top of the single crystal furnace body and used for pulling crystal downwards into the single crystal furnace body, the pulling device is connected through the rack and is erected at the top of the single crystal furnace body, and specifically, the first seat is fixedly connected to the rack, so that the pulling shaft is provided with an execution station which can downwards enter the single crystal furnace body or upwards lift from the inside of the single crystal furnace body.

The application also provides a crystal pulling method using the pulling device, as shown in fig. 4, the method comprises the following steps:

s100: firstly, driving the lifting shaft to descend so that the seed crystal on the clamp 320 contacts the silicon liquid surface;

s200: the lifting shaft is lifted upwards while being rotated by the driving mechanism;

s300: thereby obtaining the crystal bar.

Specifically, as shown in fig. 5, the step S200 of pulling up the pulling shaft while being rotated by the driving mechanism includes:

s210: driving the lifting shaft to rotate and lift, and forming fine crystals on the seed crystal;

s220: the inner shaft 110 is driven to ascend relative to the outer shaft 120, and the flexible shaft 200 is driven to retract into the inner cavity of the outer shaft 120 so as to reduce the extending length of the flexible shaft 200.

The length requirement of the flexible shaft 200 is adjusted according to the crystal pulling step, as shown in fig. 5, and the method specifically comprises the following steps:

the first stage:

the lifting shaft is in a first state, in which the flexible shaft 200 is retracted inside the outer shaft 120, so that the clamp assembly 300 is abutted against the bottom of the outer shaft 120 to form a whole; the first driving piece drives the lifting shaft to integrally descend into the single crystal furnace body;

and a second stage:

the first driving part drives the lifting shaft to descend until the seed crystal reaches a first length above the silicon liquid level, the first state of the lifting shaft is switched to a second state, the second driving part drives the inner shaft 110 to descend in the second state, the flexible shaft 200 gradually extends outwards from the inner cavity of the outer shaft 120 until the flexible shaft 200 reaches the maximum length, and the seed crystal is in contact with the silicon liquid level at the moment; wherein the first length is the length of flexible shaft 200; after the lifting shaft descends to the lowest position, the flexible shaft 200 is driven to extend, so that the swaying caused by errors or shaking in the process that the flexible shaft 200 descends along with the hard shaft 100 is reduced;

and a third stage:

in the second state, the first driving component drives the lifting shaft to integrally rotate, the first driving component drives the outer shaft 120 to integrally lift at the lifting speed of V, other factors such as temperature and the like meet the requirement of a crystal growth process, and silicon materials are gradually adsorbed on seed crystals until fine crystals of 400-500 mm are formed so as to remove dislocation among the crystals; the flexibility of the flexible shaft 200 is used for improving the concentric state of the fine crystal and the lifting shaft, reducing tangential stress during crystal growth and preventing the broken package of the crystal growth;

fourth stage:

along with the lifting of the lifting shaft, fine crystals are grown on the seed crystal, equal-diameter crystals are obtained after shouldering, the equal-diameter crystal bar is started to be pulled, along with the increase of the weight of the equal-diameter crystal bar, in the high-speed rotation process, the influence trend of the increase of the weight of the crystal bar on the shaking of the flexible shaft 200 is gradually increased, the second driving piece independently drives the inner shaft 110 to lift at the lifting speed of alpha, the first driving piece drives the outer shaft 120 to lift at the speed of V-alpha so as to keep the lifting speed of the crystals to be V, the extending length of the flexible shaft 200 is gradually reduced until the flexible shaft 200 is fully retracted into the inner cavity of the outer shaft 120, the clamp assembly 300 is propped against the bottom of the outer shaft 120 to form a whole, namely, the lifting shaft is switched from the second state back to the first state; thereby reducing the influence of crystal sloshing on the crystal pulling quality.

Working principle/steps:

the lifting shaft descends into the single crystal furnace body, the flexible shaft 200 is in an extending state to perform fine crystal growth, after shoulder placement, the flexible shaft 200 is driven to retract into the inner cavity of the outer shaft 120, the length of the flexible shaft 200 is reduced, and the crystal bar is obtained after crystal bar isodiametric growth.

The technical effects are as follows:

1. the single crystal furnace provides a novel lifting shaft, the bottom end of the hard shaft 100 is connected with the soft shaft 200, the hard shaft 100 has rigidity, the length of the soft shaft 200 is reduced compared with the traditional lifting scheme of the long soft shaft 200, and the crystal shaking amplitude formed by the soft shaft 200 can be effectively controlled; therefore, the method reduces the amplitude of crystal shaking, solves the technical problem of low crystal pulling quality, and achieves the technical effect of improving the crystal quality.

2. Because the flexible shaft 200 has flexibility, the vertical state is kept under the action of the crystal bar, the eccentric error of the hard shaft 100 is reduced, the whole concentricity of the lifting shaft is improved, the technical problem of low crystal pulling quality is solved, and the technical effect of improving the crystal quality is achieved.

3. The hard shaft 100 is divided into an outer shaft 120 and an inner shaft 110 which are respectively lifted, and crystal rod shaking generated by the single pendulum effect of the flexible shaft 200 is relieved by adjusting the extending length of the flexible shaft 200, so that the quality of the crystal rod is further improved.

While preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the spirit or scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.

Claims

1. A pulling shaft of a single crystal growing furnace, applied to the single crystal growing furnace, comprising:

a hard shaft (100), wherein the hard shaft (100) is in a long and straight state and is vertically arranged;

the first end of the flexible shaft (200) is connected to the bottom of the hard shaft (100), and the flexible shaft (200) and the hard shaft (100) are coaxially arranged; and

and the clamp assembly (300) is connected to the second end of the flexible shaft (200), and the clamp assembly (300) is used for clamping seed crystals.

2. The pulling shaft of a single crystal growing furnace of claim 1, wherein the hard shaft (100) comprises:

an outer shaft (120), wherein an inner cavity penetrating up and down is formed in the outer shaft (120);

an inner shaft (110), wherein the inner shaft (110) is positioned in an inner cavity of the outer shaft (120), the inner shaft (110) and the outer shaft (120) are coaxially arranged, the inner shaft (110) and the outer shaft (120) have mutually independent vertical movement degrees of freedom, and the inner shaft (110) and the outer shaft (120) have synchronous rotation degrees of freedom around the shaft;

wherein a first end of the flexible shaft (200) is connected to the bottom of the inner shaft (110).

3. The pulling shaft of a single crystal growing furnace according to claim 2, characterized in that the bottom of the inner cavity of the outer shaft (120) is provided with a baffle plate (121), and the baffle plate (121) is fixedly connected to the bottom of the outer shaft (120) or is integrally formed with the outer shaft (120);

the first end of the flexible shaft (200) penetrates through the partition plate (121) from bottom to top, and the first end of the flexible shaft (200) is fixed in the inner cavity of the outer shaft (120).

4. A single crystal furnace lifting shaft according to claim 3, characterized in that the two ends of the flexible shaft (200) are provided with first limit parts (210); connecting components (220) are respectively arranged at two ends of the flexible shaft (200), the flexible shaft (200) is respectively connected with the hard shaft (100) and the clamp component (300) through two groups of connecting components (220), and each group of connecting components (220) comprises:

the sleeve (221), sleeve (221) be used for with interior axle (110) or anchor clamps subassembly (300) are connected, offer on the lateral wall of sleeve (221) along first direction arrange and run through in passageway (222) of sleeve (221), passageway (222) can the holding flexible axle (200) get into in sleeve (221), the first spacing portion (210) of flexible axle (200) are inconsistent with the tip of sleeve (221) and are spacing.

5. A pulling-on shaft for a single crystal growing furnace according to claim 3, characterized in that the partition plate (121) is provided with a concave part (122) which is concave towards the inner cavity of the outer shaft (120); the top of the clamp assembly (300) is provided with a protruding part (311) conforming to the recessed part (122), and the protruding part (311) is formed with a first station and a second station along with the lifting of the inner shaft (110) and the recessed part (122):

when the bulge is at the first station, the flexible shaft (200) extends out of the outer shaft (120), and the bulge part (311) and the concave part (122) are separated from each other;

when the bulge is in the second station, the flexible shaft (200) is retracted into the outer shaft (120), and the bulge (311) and the concave part (122) are in mutual interference fit.

6. The pulling shaft of a single crystal growing furnace of claim 5, wherein the clamp assembly (300) comprises:

the balancing weight (310) is connected with the flexible shaft (200);

and the clamp (320) is connected to the bottom of the balancing weight (310), and the clamp (320) is used for connecting seed crystals.

7. A pulling apparatus for a single crystal growing furnace, applied to the single crystal growing furnace, comprising:

a lift shaft as claimed in any one of claims 2 to 6;

the driving mechanism is connected with and acts on the lifting shaft and is used for driving the lifting shaft to rotate and lift.

8. The pulling apparatus of claim 7, wherein the drive mechanism comprises;

the pedestal, the pedestal includes:

a first seat, the first seat being fixed;

a second seat; the second seat is movably connected to the second seat, and the second seat has a moving degree of freedom for vertical movement;

the first driving component is connected to the second seat, acts on the outer shaft (120) and is used for driving the outer shaft (120) to rotate so as to drive the inner shaft (110) to synchronously rotate with the outer shaft (120); and

a second drive assembly, the second drive assembly comprising:

a first driving member connected to the first seat and acting on the outer shaft (120) for driving the lifting shaft to rise and fall;

and the second driving piece is connected to the second seat and acts on the inner shaft (110) to drive the inner shaft (110) to independently lift.

9. A single crystal growing furnace, comprising:

a single crystal furnace body;

the pulling device is a pulling device as claimed in any one of claims 7 to 8, and is positioned at the top of the single crystal furnace body and used for vertically downwards entering the single crystal furnace body to pull the crystal.

10. A method of pulling a crystal using a pulling apparatus as defined in any one of claims 7 to 8, comprising:

the seed crystal on the clamp (320) is contacted with the silicon liquid surface;

the pulling shaft is driven by the driving mechanism to rotate and is pulled upwards to obtain the crystal bar.