Top and upper thermal insulation structure for single crystal thermal field device and single crystal thermal field device

Abstract

The utility model discloses a top and upper thermal insulation structure for a single crystal thermal field device and the single crystal thermal field device. The top and upper thermal insulation structure for the single crystal thermal field device comprises a guide cylinder flange, an outer guide cylinder, a guide cylinder ring felt, an inner thermal insulation cylinder and an upper thermal insulation cylinder, the guide cylinder ring felt is connected with the guide cylinder flange and is positioned above the inner thermal insulation cylinder; the guide cylinder annular felt comprises a first annular felt and a second annular felt, the first annular felt is located above the second annular felt, and the first annular felt and the second annular felt are both of an annular structure and are the same in outer diameter; the first ring felt is provided with a first through hole, the second ring felt is provided with a second through hole, and the diameter of the first through hole is smaller than that of the second through hole; the guide cylinder ring felt is of an integrally formed structure; the inner heat preservation cylinder is vertically arranged and located in the upper heat preservation cylinder. The inner heat preservation cylinder and the outer flow guide cylinder are connected and move upwards or downwards at the same time. The device disclosed by the utility model is beneficial to improving the thermal insulation performance, reducing the drawing and releasing times and improving the drawing and releasing survival rate.

Description

Technical Field

[0001] The utility model relates to a top and upper heat preservation structure for a single crystal thermal field device and a single crystal thermal field device. Background Art

[0002] The thermal system of a single crystal furnace consists of a heater, a heat preservation system, a support mechanism, a support rod, a crucible support, etc. The heater is the main body of the heat system and is made of high-purity graphite. The heat preservation system is generally composed of a mixture of several materials such as carbon fiber, carbon felt, high-purity quartz, molybdenum sheets and high-purity graphite. The main heating system of the single crystal furnace is the main heater and the bottom heater. According to the different powers of the main and bottom heaters, a power difference is formed in the entire thermal field, and then a temperature difference is formed, ensuring that the single crystal furnace can pull out high-quality single crystal silicon rods. The heat preservation is closely related to the heat preservation system, which specifically includes top heat preservation, upper heat preservation, middle heat preservation, lower heat preservation and bottom heat preservation.

[0003] The existing top insulation structure is mainly composed of guide tube flange, guide tube ring felt structure, top fixed felt and isolation ring. Figure 1 and Figure 2 As shown. Since the outer guide tube needs to move together with the water-cooled screen, the guide tube flange and the guide tube ring felt structure need to be fixed to the upper part of the outer guide tube, and the top solid felt is placed on the upper insulation tube. The guide tube ring felt structure is isolated from the top solid felt by an isolation ring. However, this relatively separated structure setting causes a large gap in the upper part of the top insulation structure, and a large amount of heat is lost from the gap, which deteriorates the overall thermal insulation performance, causing the seeding power and equal-diameter power to continue to be high, and the thermal field temperature is not stable enough. Utility Model Content

[0004] In view of this, one purpose of the utility model is to provide a top and upper insulation structure for a single crystal thermal field device. It simplifies the existing thermal field top insulation structure, eliminates the fitting gap between parts, overcomes the defect of gap heat leakage, and enhances the thermal insulation of the top insulation structure. During secondary feeding, a closed insulation structure can be formed inside the thermal field. Compared with the existing open structure, the phenomenon of heat exchange with the outside of the thermal field is avoided, which greatly reduces the loss of heat in the thermal field during secondary feeding and improves the heat utilization rate of the heater. Another purpose of the utility model is to provide a single crystal thermal field device.

[0005] The utility model adopts the following technical solutions to achieve the above-mentioned purpose.

[0006] On the one hand, the utility model provides a top and upper insulation structure for a single crystal thermal field device, including a guide tube flange and an outer guide tube; and also includes a guide tube ring felt, an inner insulation tube and an upper insulation tube;

[0007] The guide tube annular felt is connected to the guide tube flange and is located above the inner insulation tube;

[0008] The guide tube annular felt comprises a first annular felt and a second annular felt, the first annular felt is located above the second annular felt, the first annular felt and the second annular felt are both annular structures, and the outer diameters of the two are the same; the first annular felt has a first through hole, the second annular felt has a second through hole, the central axes of the first through hole and the second through hole coincide, and the diameter of the first through hole is smaller than the diameter of the second through hole; the guide tube annular felt is set as an integrally formed structure;

[0009] The inner heat-insulating tube is arranged vertically and is located inside the upper heat-insulating tube; the gap between the outer wall of the inner heat-insulating tube and the inner wall of the upper heat-insulating tube in the horizontal direction is not greater than 5 mm;

[0010] The inner insulation tube is connected to the outer guide tube, and the two are configured to move upward or downward simultaneously. This simplifies the existing thermal insulation structure at the top of the thermal field (the utility model does not involve the top solid felt and isolation ring in the prior art), eliminates the matching gap between the parts, overcomes the defect of gap heat leakage, and enhances the thermal insulation of the top insulation structure. During secondary charging, a closed thermal insulation structure can be formed inside the thermal field. Compared with the existing open structure, the phenomenon of heat exchange with the outside of the thermal field is avoided, which greatly reduces the heat loss of the thermal field during secondary charging and improves the heat utilization rate of the heater.

[0011] The guide tube ring felt is located above the outer guide tube and the inner insulation tube. The guide tube ring felt and the inner insulation tube of the utility model are used in conjunction with each other. On the one hand, the guide tube ring felt can be fixedly connected to the guide tube flange to play a fixing role. On the other hand, by setting the inner insulation tube and the outer guide tube to move upward or downward at the same time, it can be realized that the guide tube ring felt and the guide tube flange can move upward or downward at the same time. In this way, the existing top fixed felt, isolation ring and guide tube ring felt structure can be replaced, and the insulation effect is improved.

[0012] The top of the upper heat-insulating cylinder of the utility model is not connected with the annular felt of the guide cylinder, but the two can be in contact after the secondary feeding is completed.

[0013] The top of the inner heat-insulating tube is connected to the top of the outer guide tube, and the bottom of the inner heat-insulating tube is a free end.

[0014] According to the top and upper insulation structure for the single crystal thermal field device of the utility model, preferably, the gap between the outer wall of the inner insulation tube and the inner wall of the upper insulation tube along the horizontal direction is 2-3 mm, which is conducive to improving the insulation effect.

[0015] According to the top and upper insulation structure for the single crystal thermal field device described in the utility model, preferably, the inner insulation cylinder includes an inner insulation cylinder body and an inner extension, the inner insulation cylinder body is set as a cylindrical structure; the inner extension is set to be formed by extending from the top of the inner insulation cylinder body to its central axis in the horizontal direction; the top of the outer guide cylinder is connected to the free end of the inner extension of the inner insulation cylinder. Such an inner insulation cylinder is conducive to being connected to the top of the outer guide cylinder and can support the guide cylinder ring felt.

[0016] According to the top and upper insulation structure for the single crystal thermal field device described in the utility model, preferably, the thickness of the guide tube ring felt is 80-100 mm. This is conducive to improving the insulation effect. According to one embodiment of the utility model, the thickness of the guide tube ring felt is 85-95 mm.

[0017] On the other hand, the utility model further provides a single crystal thermal field device, preferably, comprising a lower insulation tube, a crucible, a main heater, a bottom heater, an inner guide tube, a water cooling screen and the top and upper insulation structures for the single crystal thermal field device as described above; wherein,

[0018] The guide tube flange, guide tube ring felt, inner guide tube and outer guide tube form a heat shield structure; the heat shield structure is connected to the water cooling shield through a movable hanging part;

[0019] The lower heat-insulating cylinder is located below the upper heat-insulating cylinder, and the crucible is located in the lower heat-insulating cylinder; the main heater is arranged near the upper part of the crucible; and the bottom heater is arranged near the bottom of the crucible.

[0020] In the utility model, the outer guide ring, the inner guide support ring, the inner guide tube, the outer guide tube and the water cooling screen can all adopt those in the prior art.

[0021] In the utility model, the lower heat preservation cylinder, the crucible, the main heater and the bottom heater can adopt those in the prior art. The crucible is used to contain silicon material and molten silicon material liquid.

[0022] According to the single crystal thermal field device described in the utility model, preferably, it also includes an inner guide support ring and an outer guide ring; the lower end of the inner guide tube is connected to the inner guide support ring; the lower end of the outer guide tube is connected to the outer guide ring.

[0023] According to the single crystal thermal field device described in the utility model, preferably, the upper heat preservation cylinder is a cylindrical structure.

[0024] According to the single crystal thermal field device described in the utility model, preferably, the bottom of the upper thermal insulation cylinder is connected to the top of the lower thermal insulation cylinder.

[0025] According to the single crystal thermal field device of the present invention, preferably, the diameter of the lower thermal insulation cylinder is greater than the diameter of the upper thermal insulation cylinder.

[0026] According to the single crystal thermal field device of the utility model, preferably, the upper insulation tube and the guide tube ring felt are not connected.

[0027] The utility model simplifies the existing thermal insulation structure at the top of the thermal field, eliminates the matching gap between parts, overcomes the defect of heat leakage in the gap, and enhances the thermal insulation of the top thermal insulation structure. During secondary feeding, a closed thermal insulation structure can be formed inside the thermal field. Compared with the existing open structure, the phenomenon of heat exchange with the outside of the thermal field is avoided, the heat loss of the thermal field during secondary feeding is greatly reduced, and the heat utilization rate of the heater is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the top insulation structure of an existing single crystal thermal field device.

[0029] Figure 2 It is a schematic diagram of the structure of the existing top solid felt.

[0030] Figure 3 It is a schematic diagram of the structure of the single crystal thermal field device of the utility model during secondary feeding.

[0031] Figure 4 It is a schematic diagram of the structure of the single crystal thermal field device of the utility model after the secondary feeding is completed.

[0032] Figure 5 It is a structural schematic diagram of the guide tube ring felt of the utility model.

[0033] Figure 6 It is a schematic structural diagram of the inner heat-insulating cylinder of the present utility model.

[0034] Figure 7 This is a comparison chart of the number of releases.

[0035] The following are the descriptions of the reference numerals:

[0036] In the existing top and upper insulation structure: 1- water cooling screen; 2- guide tube ring felt structure; 3- top fixed felt; 52- outer guide tube, 61- upper insulation tube I.

[0037] In the single crystal thermal field device of the utility model: 1-water cooling screen, 20-guide tube ring felt, 21-first through hole, 22-second through hole, 30-inner insulation tube, 31-inner insulation tube body, 32-inner extension, 40-guide tube flange, 51-inner guide tube, 511-inner guide support ring, 52-outer guide tube, 521-outer guide ring, 53-movable hanging part, 60-upper insulation tube, 70-lower insulation tube, 91-main heater, 92-bottom heater. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0039] Explanation of relevant terms:

[0040] Number of lead-in and release: From seed crystal fusion to shoulder release to reaching the required diameter is one lead-in and release.

[0041] The survival rate of seeding: From the process of seeding to equal diameter, the atoms of the single crystal are arranged and distributed all the time, and no other atomic arrangements appear. This is called seeding survival. The number of single crystals pulled in each furnace divided by the number of seeding times is called the seeding survival rate.

[0042] Example 1

[0043] Figure 3 The utility model is a structural schematic diagram of a single crystal thermal field device during secondary feeding. Figure 4 The utility model is a structural schematic diagram of a single crystal thermal field device after the secondary feeding is completed. Figure 5 It is a structural schematic diagram of the guide tube ring felt of the utility model. Figure 6 It is a schematic structural diagram of the inner heat-insulating cylinder of the present utility model. Figure 7 It is a comparison chart of the number of lead-in and release (the furnace station of the same period refers to the use of the existing single crystal thermal field device and the existing method for pulling crystals; the test furnace station refers to the use of the single crystal thermal field device of the utility model and the method of the utility model for pulling crystals). Figure 1 This is a schematic diagram of the top insulation structure of an existing single crystal thermal field device. Figure 2 It is a schematic diagram of the structure of the existing top solid felt.

[0044] like Figure 3 and Figure 4 As shown, the top insulation structure of the single crystal thermal field device of the utility model does not need an isolation ring. The existing relatively separated guide tube ring felt structure 2 (see Figure 1 ), top felt 3 (see Figure 1 , Figure 2 ) and an isolation ring (not shown) are integrated to design an integrally formed structure - a guide tube ring felt 20. In conjunction with the guide tube ring felt 20, an inner insulation tube 30 is added. A new top and upper insulation structure is obtained. These are the improvements of the single crystal thermal field device of the utility model. The positional relationship and connection relationship of other components are basically the same as those in the prior art, and are not described in detail in this embodiment.

[0045] Specifically, Figure 3 , Figure 4As shown, the single crystal thermal field device of the utility model comprises a water cooling shield 1, a guide tube ring felt 20, an inner insulation tube 30, a guide tube flange 40, an inner guide tube 51, an inner guide support ring 511, an outer guide tube 52, an outer guide ring 521, an upper insulation tube 60, a lower insulation tube 70, a crucible (not shown), a main heater 91 and a bottom heater 92. Among them, the guide tube ring felt 20, the guide tube flange 40, the inner insulation tube 30, and the upper insulation tube 60 form the top and upper insulation structure of the utility model.

[0046] The guide tube ring felt 20 is connected to the guide tube flange 40 and is located above the inner insulation tube 30 and the outer guide tube 52. The thickness of the guide tube ring felt is 80-100 mm, for example, 90 mm.

[0047] like Figure 3 , Figure 4 , Figure 5 As shown, the guide tube ring felt 20 includes a first ring felt and a second ring felt, the first ring felt is overlapped and arranged above the second ring felt, the first ring felt and the second ring felt are both annular structures, and the outer diameters of the two are the same; the first ring felt has a first through hole 21, and the second ring felt has a second through hole 22, the central axes of the first through hole 21 and the second through hole 22 coincide, and the diameter of the first through hole 21 is smaller than the diameter of the second through hole 22. The first through hole 21 and the second through hole 22 can be used to pass a part of the water cooling screen 1 and a part of the inner guide tube 21, and the edge of the second through hole 22 can be used to assist in fixing a part of the outer guide tube 52. The thickness of the first ring felt is greater than that of the second ring felt. The guide tube ring felt 20 is set as an integrally formed structure. Compared with the existing relatively separated top fixed felt, isolation ring and guide tube ring felt structure, the guide tube ring felt with such a structure improves the thermal insulation effect.

[0048] like Figure 3 , Figure 4 , Figure 6 As shown, the inner heat-insulating tube 30 is arranged vertically and is located inside the upper heat-insulating tube 60. The gap between the outer wall of the inner heat-insulating tube 30 and the inner wall of the upper heat-insulating tube 60 along the horizontal direction is not greater than 5 mm, for example, it can be 2 to 3 mm. The inner heat-insulating tube 30 can move upward or downward. The inner heat-insulating tube 30 is connected to the outer guide tube 52, and the two can move upward or downward at the same time.

[0049] like Figure 6 As shown, the inner heat-insulating cylinder 30 includes an inner heat-insulating cylinder body 31 and an inner extension 32, and the inner heat-insulating cylinder body 31 is set as a cylindrical structure. The inner extension 32 is formed by extending the top of the inner heat-insulating cylinder body 31 toward its central axis in a horizontal direction. The top of the outer guide cylinder 52 is connected to the free end of the inner extension 32 of the inner heat-insulating cylinder 30.

[0050] The upper heat preservation cylinder 60 of the utility model is a cylindrical structure, the top of which is not connected to the bottom of the guide cylinder ring felt 20, and can be in contact with each other after the secondary feeding is completed. The structure is the same as that of the existing upper heat preservation cylinder I 61.

[0051] The lower end of the inner guide tube 51 is connected to the inner guide support ring 511. The lower end of the outer guide tube 52 is connected to the outer guide ring 521. The guide tube flange 40, the guide tube ring felt 20, the inner guide tube 51 and the outer guide tube 52 form a heat shield structure; the heat shield structure is connected to the water-cooled shield 1 through a movable hanging part 53. In this way, the heat shield structure can move upward or downward together with the water-cooled shield 1, thereby improving the heat preservation effect.

[0052] The lower heat-insulating tube 70 is located below the upper heat-insulating tube 60, and the crucible is located in the lower heat-insulating tube 70. The main heater 91 is disposed near the upper portion of the crucible. The bottom heater 92 is disposed near the bottom of the crucible.

[0053] The following describes the connection and installation process of some components of the single crystal thermal field device of this embodiment:

[0054] First, the guide tube ring felt 20 is rolled in the outer guide tube 52 according to the standard, and the outer guide ring 521 and the inner guide support ring 511 are placed. Then the inner guide tube 51 is inserted into the inside, and the lower end face of the inner guide tube 51 is placed on the end face of the inner guide support ring 511. Then the guide tube ring felt 20 and the guide tube flange 40 are placed on the outer guide tube 52 in sequence. After the assembly is completed, the whole is placed on the upper end face of the inner guide tube 51, and it is ensured that the holes correspond to each other. The hanger is passed through the position of the hole of the part, and it is tightened and fixed to form a new type of heat shield structure.

[0055] The heat shield structure is hung on the water-cooled shield 1 through the movable hanging part 53. When the secondary material is added, the heat shield structure is moved into the single crystal furnace through the auxiliary equipment. After the furnace is closed, the single crystal thermal field device is as follows: Figure 3 As shown. When the main heater 91 and the bottom heater 92 heat the melt, the thermal field structure forms a closed insulation structure. Compared with the original thermal field, there is no gap. The power of the main heater 91 can be adjusted down accordingly. When the secondary feeding is completed, the guide tube ring felt 20 is placed on the upper end of the upper insulation tube 60, the lower end of the inner insulation tube 30 is flush with the lower end of the upper insulation tube 60, and the movable hanging part 53 is separated from the water cooling screen 1. The single crystal thermal field device is as shown. Figure 4 Then, the steps of welding, seeding, shoulder release, shoulder rotation, equal diameter and finishing are carried out. Since there is no gap for heat leakage in the improved structure, the thickness is also increased accordingly, which greatly improves the thermal insulation performance.

[0056] The following describes a method for using the single crystal thermal field device as described above to pull crystals and reduce the number of lead-out times. The method includes a melting step, a welding step, a seeding step, a shoulder release step, a shoulder rotation step, and a diameter equalization step.

[0057] During the silicon raw material feeding process, the power of the main heater 91 is set to 90 kW, and the power of the bottom heater 92 is set to 95 kW. During the melting process, the temperature of the liquid (silicon liquid) is regulated to 1455° C. for 30 minutes, and the bottom heater 92 is turned off.

[0058] During the welding process, the temperature of the liquid is gradually increased to 1460°C, and the welding operation is performed. After welding, the temperature of the liquid is gradually reduced to 1450°C, and the liquid temperature is kept stable. The stabilization time is 30 minutes, and the distance between the inlet and outlet of the liquid (referring to the distance between the inlet and outlet in the seeding step and the shoulder release step) is regulated within 30-35mm.

[0059] In the seeding step, the seeding pulling speed is regulated to 300 mm / h, and the diameter of the fine crystal is 5 mm. When the liquid mouth distance, seeding pulling speed and shoulder release time are all within the control range, the seeding power is set to the standard seeding power.

[0060] In the shoulder release step, the shoulder release time is 2.5 hours, the shoulder release length is 160 mm, and the specific parameters in the shoulder release step are shown in Table 1.

[0061] After entering the equal diameter step, the liquid port distance in the equal diameter step is adjusted to 20mm. When the shoulder length is in the set range, the equal diameter power is not adjusted. When the shoulder length is not in the set range, it is adjusted accordingly according to P = (L1-L0) / 100×0.5. Among them, P is the adjustment power value, L1 is the set shoulder length, and L0 is the current shoulder length.

[0062] The method of this embodiment controls the temperature of the silicon raw material melting stage, the welding stage and the post-welding stage before seeding, so that the temperature of each stage is within a reasonable range, avoiding welding at too high or too low a temperature, thereby improving the seeding survival rate of the single crystal silicon rod; and by regulating the seeding pulling speed, the shoulder length and the liquid mouth distance, the seeding power is further regulated, thereby ensuring the smooth progress of the seeding process, thereby further improving the seeding survival rate of the single crystal silicon rod, and improving the output and production efficiency.

[0063] Table 1

[0064]

[0065] The utility model shows the technical effect of improving the survival rate of release by reducing the number of releases. Figure 7 .Depend on Figure 7 It can be seen that the device and method of the utility model can effectively maintain a constant temperature, thereby reducing the number of inductions and improving the survival rate of inductions. In other words, the utility model can achieve the purpose of survival by providing a stable thermal field and improving the success rate of induction.

[0066] The present invention is not limited to the above-mentioned embodiments. Without departing from the essential content of the present invention, any deformation, improvement, and substitution that can be thought of by those skilled in the art shall fall within the scope of the present invention.

Claims

1. A top and upper insulation structure for a single crystal thermal field device, comprising a guide tube flange and an outer guide tube; characterized in that: It also includes a guide tube ring felt, an inner insulation tube and an upper insulation tube; The guide tube annular felt is connected to the guide tube flange and is located above the inner insulation tube; The guide tube annular felt comprises a first annular felt and a second annular felt, the first annular felt is located above the second annular felt, the first annular felt and the second annular felt are both annular structures, and the outer diameters of the two are the same; the first annular felt has a first through hole, the second annular felt has a second through hole, the central axes of the first through hole and the second through hole coincide, and the diameter of the first through hole is smaller than the diameter of the second through hole; the guide tube annular felt is set as an integrally formed structure; The inner heat-insulating tube is arranged vertically and is located inside the upper heat-insulating tube; the gap between the outer wall of the inner heat-insulating tube and the inner wall of the upper heat-insulating tube in the horizontal direction is not greater than 5 mm; The inner heat-insulating cylinder is connected to the outer flow-guiding cylinder, and the two are configured to move upward or downward simultaneously.

2. The top and upper insulation structure for a single crystal thermal field device according to claim 1, characterized in that: The gap between the outer wall of the inner heat-insulating tube and the inner wall of the upper heat-insulating tube in the horizontal direction is 2 to 3 mm.

3. The top and upper insulation structure for a single crystal thermal field device according to claim 1, characterized in that: The inner insulation cylinder includes an inner insulation cylinder body and an inner extension portion, wherein the inner insulation cylinder body is configured as a cylindrical structure; the inner extension portion is configured to be formed by extending horizontally from the top of the inner insulation cylinder body toward its central axis; the top of the outer guide cylinder is connected to the free end of the inner extension portion of the inner insulation cylinder.

4. The top and upper insulation structure for a single crystal thermal field device according to claim 1, characterized in that: The thickness of the guide tube ring felt is 80-100 mm.

5. A single crystal thermal field device, characterized in that: It comprises a lower insulation tube, a crucible, a main heater, a bottom heater, an inner guide tube, a water cooling screen, and the top and upper insulation structures for the single crystal thermal field device according to claim 1; wherein, The guide tube flange, guide tube ring felt, inner guide tube and outer guide tube form a heat shield structure; the heat shield structure is connected to the water cooling shield through a movable hanging part; The lower heat-insulating cylinder is located below the upper heat-insulating cylinder, and the crucible is located in the lower heat-insulating cylinder; the main heater is arranged near the upper part of the crucible; and the bottom heater is arranged near the bottom of the crucible.

6. The single crystal thermal field device according to claim 5, characterized in that: It also includes an inner guide support ring and an outer guide ring; the lower end of the inner guide cylinder is connected to the inner guide support ring; the lower end of the outer guide cylinder is connected to the outer guide ring.

7. The single crystal thermal field device according to claim 5, characterized in that: The upper heat-insulating cylinder is a cylindrical structure.

8. The single crystal thermal field device according to claim 5, characterized in that: The bottom of the upper heat-insulating tube is connected to the top of the lower heat-insulating tube.

9. The single crystal thermal field device according to claim 5, characterized in that: The diameter of the lower heat-insulating tube is greater than the diameter of the upper heat-insulating tube.

10. The single crystal thermal field device according to claim 5, characterized in that: The upper heat-insulating tube is not connected to the guide tube annular felt.

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