Volatilization and falling prevention device of single crystal furnace seed crystal lifting and rotating structure

Abstract

The utility model relates to the technical field of single crystal furnaces, in particular to a volatilization and falling prevention device of a single crystal furnace seed crystal lifting and rotating structure. The inner diameter of the fixing sleeve is in transition fit with the outer diameter of a rotating shaft, a radial positioning mechanism is arranged between the fixing sleeve and the rotating shaft rod, a collecting and guiding mechanism is arranged at the top of the fixing sleeve, and the edge of the collecting and guiding mechanism is in clearance fit with the inner wall of a shaft rod cavity. By arranging the collecting and guiding mechanism, rising metal volatile matter can be intercepted and guided, the attachment amount of the metal volatile matter on the surface of the rotating shaft rod is reduced, the collecting and guiding mechanism can prevent the fallen volatile matter from directly falling back into a melt, and the melt component pollution risk is reduced; the structure stability in a high-temperature environment is favorably maintained, and the normal lifting and rotating motion of the seed rod are not influenced.

Description

TECHNICAL FIELD

[0001] The utility model relates to single crystal furnace technical field, concretely is a single crystal furnace seed crystal lifting rotation structure prevents volatile back -fall device. BACKGROUND

[0002] In the field of semiconductor and photovoltaic material preparation, single crystal furnace is an important equipment for growing high-purity single crystal silicon, gallium arsenide (GaAs) and other key materials. Single crystal furnace is usually composed of a main furnace body at the bottom and an upper elongated seed crystal lifting and rotating shaft chamber. The main furnace body contains high-temperature molten raw materials (such as Cd, Si, etc.), and single crystals are grown by the Czochralski method. During the crystal growth process, the seed crystal rod needs to be precisely lifted and rotated in a high-temperature environment to ensure the uniformity and structural integrity of the crystal growth.

[0003] However, in a high-temperature environment, molten metal (such as Cd) is prone to volatilization, and its vapor will rise with the airflow and adhere to the surface of the seed crystal lifting and rotating shaft. With the reciprocating motion of the shaft, these volatile substances may fall off due to friction or vibration, back into the melt, causing contamination of the melt composition and affecting the purity and growth quality of the single crystal. In addition, the relative motion between the shaft and the sealing structure at the top of the chamber may exacerbate the peeling of volatile substances, further increasing the risk of crystal defects. SUMMARY

[0004] The utility model aims at solving the above-mentioned problem, thus providing a single crystal furnace seed crystal lifting and rotating structure volatile back -fall device that helps to reduce the formation of crystal defects.

[0005] The utility model solves the problem by adopting the following technical scheme:

[0006] A single crystal furnace seed crystal lifting and rotating structure volatile back -fall device, comprising a fixed sleeve coaxially sleeved at the bottom of the rotating shaft, the inner diameter of the fixed sleeve and the outer diameter of the rotating shaft are in transition fit, a radial positioning mechanism is provided between the fixed sleeve and the rotating shaft, and a collection and flow guide mechanism is provided at the top of the fixed sleeve, the edge of the collection and flow guide mechanism is in gap fit with the inner wall of the shaft chamber.

[0007] The utility model adopting the above technical scheme has the following outstanding features compared with the prior art:

[0008] By setting the collection and flow guide mechanism, the rising metal volatile substances can be intercepted and guided, reducing their adhesion on the surface of the rotating shaft. The collection and flow guide mechanism can block the already fallen volatile substances from directly falling back into the melt, reducing the risk of melt composition contamination. The transition fit of the fixed sleeve and the rotating shaft combined with the radial positioning mechanism helps to maintain the structural stability in a high-temperature environment without affecting the normal lifting and rotating motion of the seed crystal rod.

[0009] As preferred, the utility model further provides a technical scheme, which is characterized in that:

[0010] Further, the radial positioning mechanism comprises a threaded hole formed on the fixing sleeve, a positioning screw is screwed in the threaded hole, and the end of the positioning screw is in surface contact with the rotary shaft rod.

[0011] Further, the threaded hole is formed on the fixing sleeve in a circumferential direction and is evenly formed in at least three, and this symmetrical distribution mode can make the clamping force of the positioning screw on the shaft rod more balanced.

[0012] Further, the collecting and guiding mechanism comprises a cover body, the cover body is in an inverted hollow truncated cone structure, the bottom end of the cover body is integrally formed with the top end of the fixing sleeve, the top end outer edge of the baffle is in gap cooperation with the inner wall of the shaft rod chamber, the interception area of the volatile matter can be enlarged, the conical structure is helpful for guiding the volatile matter to deposit along the inclined surface. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a relative structure schematic view when the utility model embodiment works.

[0014] Figure 2 It is a top view structure schematic view of the utility model embodiment.

[0015] Figure 3 It is a main view cross section structure structure schematic view of the utility model embodiment.

[0016] Figure 4 It is a side view structure schematic view of the utility model embodiment.

[0017] In the drawing, the marks are: rotary shaft rod 1, fixing sleeve 2, cover body 3, threaded hole 4, positioning screw 5, shaft rod chamber 6, main furnace body 7. DETAILED DESCRIPTION

[0018] The utility model will be further explained in combination with examples, the purpose is only in better understanding the utility model content, therefore, the example does not limit the protection scope of the utility model.

[0019] A single crystal furnace seed crystal lifting and rotating structure volatile back-falling prevention device, comprising a fixed sleeve 2 coaxially sleeved at the bottom of a rotating shaft 1, the inner diameter of the fixed sleeve 2 is in transition fit with the outer diameter of the rotating shaft, a radial positioning mechanism is arranged between the fixed sleeve 2 and the rotating shaft 1, and the top of the fixed sleeve 2 is provided with a collecting and guiding mechanism.

[0020] Further, the radial positioning mechanism comprises a threaded hole 4 formed in the fixed sleeve 2, a positioning screw 5 is screwed in the threaded hole 4, and the end of the positioning screw 5 is in contact with the surface of the rotating shaft 1; the radial positioning mechanism is realized by arranging the threaded hole 4 on the fixed sleeve 2 and cooperating with the positioning screw 5; the positioning screw 5 is made of a high-temperature-resistant alloy, and reliable positioning between the device and the rotating shaft 1 can be realized. The structure design is convenient for installation and adjustment, the contact pressure of the positioning screw 5 and the surface of the shaft can be adjusted, which is helpful to adapt to the thermal expansion difference under different working conditions and improve the stability of the device in a high-temperature environment.

[0021] Further, the threaded hole 4 is uniformly formed in the fixed sleeve 2 in at least three circumferential directions, and this symmetrical distribution can make the clamping force of the positioning screw 5 on the shaft more balanced. The cooperation of multiple threaded holes 4 can effectively prevent the device from circumferential deviation during rotation, reduce the risk of changes in the fit clearance caused by thermal deformation, and be helpful to maintain the gap stability of the collecting and guiding mechanism and the inner wall of the chamber.

[0022] Further, the collecting and guiding mechanism comprises a cover body 3, the fixed sleeve 2 and the cover body 3 are made of 316 stainless steel, the cover body 3 is in the form of an inverted hollow truncated cone structure, the bottom end of the cover body 3 is integrally formed with the top end of the fixed sleeve 2, the outer edge of the top end of the baffle is in gap fit with the inner wall of the shaft chamber 6, the gap is between 0.5-1.2mm, which can expand the interception area of the volatile substances, and the conical structure is helpful to guide the volatile substances to deposit along the inclined surface. The integrally formed design of the cover body 3 and the fixed sleeve 2 can reduce the risk of air leakage at the connection part and improve the overall structure. The gap fit between the outer edge of the top end and the inner wall of the chamber not only ensures the blocking effect on the volatile substances, but also avoids the movement interference with the chamber structure, providing sufficient space for the normal lifting and rotating of the seed crystal rod. The gap fit between the outer edge of the top end of the baffle and the inner wall of the shaft chamber 6 can ensure the interception effect of the volatile substances while adapting to the thermal expansion difference of each part in a high-temperature environment, and the appropriate fit gap can avoid the mechanical jamming caused by thermal deformation, ensuring the reliable operation of the device under long-term high-temperature working conditions.

[0023] The fixed sleeve 2 is reliably positioned with the rotating shaft 1 through transition fit and at least three circumferentially evenly distributed positioning screws 5. During the operation of the single crystal furnace, when the molten metal in the main furnace body 7 generates volatile matter at high temperature and moves upward, the cover body 3 in the inverted truncated cone structure changes the originally vertically rising metal vapor into a slanting movement path with its enlarged interception area and inclined surface design, significantly reducing the amount of volatile matter entering the cavity of the seed rod lifting and rotating shaft 1. At the same time, the gap fit design between the outer edge of the top end of the cover body 3 and the inner wall of the shaft cavity 6 ensures the interception effect of the volatile matter and avoids mechanical jamming under high temperature working condition by reserving appropriate gap. During the whole crystal pulling process, whether the seed rod is lifted or rotated, the device can continuously collect the condensed metal volatile matter and prevent it from falling back to the melt through its flow guide structure, thereby maintaining the stability of the melt composition.

[0024] By setting the collection and flow guide mechanism, the rising metal volatile matter can be intercepted and guided, the amount of adhesion on the surface of the rotating shaft 1 is reduced, the collection and flow guide mechanism can block the already detached volatile matter from directly falling back to the melt, the risk of melt composition pollution is reduced, the transition fit of the fixed sleeve 2 and the rotating shaft 1 combined with the radial positioning mechanism is beneficial to maintain the structural stability under high temperature environment, and does not affect the normal lifting and rotating movement of the seed rod.

[0025] The above only describes the preferred and feasible embodiments of the present application, and does not limit the scope of the present application. Any equivalent changes made according to the content of the present application and the drawings are included in the scope of the present application.

Claims

1. A device for preventing the volatilization and fall of a seed crystal lifting and rotating structure in a single crystal furnace, characterized in that: The fixed sleeve is coaxially sleeved at the bottom of the rotating shaft rod, the inner diameter of the fixed sleeve is transitionally matched with the outer diameter of the rotating shaft, a radial positioning mechanism is arranged between the fixed sleeve and the rotating shaft rod, the top of the fixed sleeve is provided with a collecting and guiding mechanism, and the edge of the collecting and guiding mechanism is gap matched with the inner wall of the shaft rod chamber.

2. The apparatus according to claim 1, wherein the apparatus is a single crystal furnace seed crystal lifting and rotating structure volatile backfall prevention device. The radial positioning mechanism comprises a threaded hole opened on the fixed sleeve, and a positioning screw is screwed in the threaded hole, and the end of the positioning screw is in contact with the surface of the rotating shaft rod.

3. The apparatus according to claim 2, wherein the apparatus is characterized by: The threaded hole is circumferentially and evenly opened on the fixed sleeve for at least three times.

4. The apparatus according to claim 1, wherein the apparatus is characterized by: The collecting and guiding mechanism comprises a cover body, the cover body is in an inverted hollow truncated cone structure, the bottom end of the cover body is integrally formed with the top end of the fixed sleeve, and the top end of the cover body is gap matched with the inner wall of the shaft rod chamber.

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