Crystal growth device and method for determining crystal seeding crucible position

Abstract

The present invention relates to a crystal growth device, comprising: a furnace body; a crucible for containing molten silicon; a heater structure, which is arranged around the periphery of the crucible to heat the crucible; a thermal insulation layer, which is arranged on the periphery of the heater structure; a guide tube, which is barrel-shaped and is arranged vertically above the molten silicon in the furnace body; a guide tube lifting structure, which is arranged on the top of the furnace body and is used to control the lifting and lowering of the guide tube, and to ensure that there is always a gap between the guide tube and the thermal insulation layer in the axial direction of the furnace body. The present invention also relates to a method for determining the position of a crystal seeding crucible. The lifting and lowering of the guide tube is controlled by the guide tube lifting structure, and a gap is always provided between the guide tube and the thermal insulation layer in the axial direction of the furnace body. Compared with the traditional technology, the guide tube is supported on the top of the thermal insulation layer, which solves the problem of the change in the position of the guide tube caused by the deformation of the thermal insulation layer, and ensures the stability of the relative position relationship between the liquid level position and the guide tube.

Description

Technical Field

[0001] The invention relates to the technical field of silicon product manufacturing, and in particular to a crystal growth device and a method for determining a crystal seeding crucible position. Background Art

[0002] In the semiconductor field, during the seeding process of silicon single crystal rod growth, it is necessary to confirm the seeding crucible position of each furnace, and to confirm the appropriate seeding crucible position by controlling the liquid level distance from the guide tube to the silicon solution surface, and then find the appropriate seeding temperature to pull the single crystal. In addition, for different liquid level heights, in order to control the stable crystal diameter, it is necessary to frequently adjust the position or angle of the diameter control sensor, so a stable liquid level position is particularly important for diameter control.

[0003] The current method for determining the seeding crucible position is: before opening the furnace, the operator first measures the length of the protruding part of the probe. After the furnace is opened and the melting is completed, the guide tube is lowered to the cover plate. The operator first raises the crucible position until the probe contacts the liquid surface of the silicon melt, and then records the contact crucible position. Then, according to the seeding liquid level spacing required by the process, the length of the protruding part of the probe is subtracted to obtain the distance the crucible needs to be lowered, thereby determining the seeding crucible position. This operation is due to the deformation of the thermal insulation layer of the thermal field during the furnace opening process. The guide tube is placed on the cover plate on top of the insulation layer. The position of the guide tube will change with the deformation of the thermal field. After confirming the seeding crucible position, the position of the liquid surface changes relative to the position of the guide tube, affecting the control of the diameter, temperature, and pulling speed of each furnace, and thus affecting the quality of the crystal rod. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a crystal growth device and a method for determining the crystal seeding crucible position, which solves the problem that the position of the guide tube changes with the deformation of the insulation layer, causing the position of the liquid crystal crucible to change.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted in the embodiment of the present invention is: a crystal growth device, comprising:

[0006] Furnace body;

[0007] A crucible, disposed inside the furnace body, for containing molten silicon;

[0008] A heater structure is disposed around the periphery of the crucible to heat the crucible;

[0009] A heat-insulating layer is disposed on the periphery of the heater structure;

[0010] A guide tube is vertically arranged above the silicon melt in the furnace body;

[0011] The guide tube lifting structure is arranged on the top of the furnace body, and is used to control the lifting and lowering of the guide tube, and to ensure that there is a gap between the guide tube and the insulation layer along the axial direction of the furnace body.

[0012] Optionally, the furnace body includes a furnace cover, and the guide tube lifting structure includes a lifting rod and a lifting unit for controlling the lifting of the lifting rod, and the pulling rod passes through the furnace cover and is connected to the guide tube.

[0013] Optionally, the lifting unit includes a lead screw and a drive motor;

[0014] The lifting rod is connected to the lead screw via a connecting block bolt;

[0015] The driving motor is used to drive the lead screw to rotate so as to control the lifting rod to move along the lead screw so as to drive the guide cylinder to rise and fall.

[0016] Optionally, it further comprises a scale fixed on the furnace cover, the scale is located on one side of the lifting rod, and the scale values ​​on the scale are set along the lifting direction of the guide tube;

[0017] A pointing block is arranged on one side of the lifting rod facing the scale.

[0018] Optionally, there is a gap between one end of the heat-insulating layer close to the top of the furnace body and one end of the guide tube close to the top of the furnace body.

[0019] Optionally, a wind shield is provided at one end of the guide tube close to the top of the furnace body, and in the radial direction of the furnace body, part of the wind shield extends above the insulation layer to shield part of the insulation layer, and there is a gap between the wind shield and the insulation layer.

[0020] Optionally, the cross-sectional shape of the wind shield in the axial direction of the furnace body is Z-shaped, and the wind shield includes a first part connected to the guide tube, a second part located above the insulation layer, and a third part located between the first part and the second part, and the first part and the second part are arranged in parallel.

[0021] Optionally, the orthographic projection of the wind shield on the insulation layer covers a first area at the top of the insulation layer, and the first area sinks toward the bottom of the furnace body to form a groove.

[0022] The embodiment of the present invention further provides a method for determining the seeding crucible position, which is determined by using the above-mentioned crystal growth device, and includes the following steps:

[0023] After the material is oxidized, the guide tube and / or the crucible are controlled to move up and down so that the probe at one end of the guide tube close to the bottom of the furnace body contacts the silicon melt;

[0024] Determine the distance that the guide tube or the crucible needs to be raised or lowered according to the preset liquid level interval, and control the guide tube or the crucible to be raised or lowered according to the distance to determine the seeding crucible position;

[0025] There is a gap between the guide tube and the insulation layer along the axial direction of the furnace body.

[0026] Optionally, the furnace body includes a furnace cover, the guide tube lifting structure includes a lifting rod and a lifting unit for controlling the lifting of the lifting rod, and the lifting rod passes through the furnace cover and is connected to the guide tube;

[0027] The lifting unit includes a lead screw and a drive motor;

[0028] The lifting rod is connected to the lead screw via a connecting block bolt;

[0029] The driving motor is used to drive the lead screw to rotate so as to control the lifting rod to move along the lead screw so as to drive the guide cylinder to rise and fall;

[0030] The crystal growth device further comprises a scale fixed on the furnace cover, the scale is located on one side of the lifting rod, and the scale values ​​on the scale are arranged along the lifting direction of the guide tube;

[0031] A pointing block is provided on one side of the lifting rod facing the scale;

[0032] The method for determining the seeding crucible position comprises the following steps:

[0033] After the material is oxidized, the crucible is controlled to rise to the preset position;

[0034] Control the guide tube to descend until the probe at one end of the guide tube close to the bottom of the furnace body contacts the silicon melt, and record the current scale value;

[0035] The distance that the guide tube needs to rise is determined according to the preset liquid level spacing, and the rise of the guide tube is controlled according to the distance, and the scale value after the guide tube rises is recorded, and the position of the scale value is used as the standard position of the guide tube under the same process conditions.

[0036] The beneficial effects of the present invention are: the lifting and lowering of the guide tube is controlled by the guide tube lifting structure, and a gap is always provided between the guide tube and the insulation layer in the axial direction of the furnace body. Compared with the traditional technology, the guide tube is supported on the top of the insulation layer, which solves the problem of position change of the guide tube caused by deformation of the insulation layer, and ensures the stability of the relative position relationship between the liquid level and the guide tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram showing a crystal growth apparatus in an embodiment of the present invention;

[0038] Figure 2 Schematic diagram showing the positional relationship between the guide tube and the insulation layer in the embodiment of the present invention Figure 1 ;

[0039] Figure 3 Schematic diagram showing the positional relationship between the guide tube and the insulation layer in the embodiment of the present invention Figure 2 ;

[0040] Figure 4 A schematic flow chart showing a method for determining a seeding crucible position in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0042] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0043] refer to Figure 1-Figure 3 , this embodiment provides a crystal growth device, including:

[0044] Furnace body 10;

[0045] The crucible 9 is disposed inside the furnace body 10 and is used to contain molten silicon;

[0046] A heater structure 101 is disposed around the periphery of the crucible 9 to heat the crucible 9;

[0047] A heat-insulating layer 7, disposed on the periphery of the heater structure 101;

[0048] The guide tube 1 is barrel-shaped and is vertically arranged above the silicon melt in the furnace body 10;

[0049] The guide tube 1 lifting structure is arranged at the top of the furnace body 10 and is used to control the lifting and lowering of the guide tube 1 so that there is always a gap between the guide tube 1 and the insulation layer 7 in the axial direction of the furnace body 10 .

[0050] In the conventional technology, the guide tube 1 is supported on the cover plate 71 on the top of the insulation layer 7. After the guide tube 1 is placed on the cover plate 71, the crucible 9 is first raised to make the silicon melt contact with the protruding part of the probe 11. After recording the contact crucible position, the crucible 9 is controlled to descend according to the required liquid level spacing to determine the crystal seeding crucible position. In the process of determining the crystal seeding crucible position, the guide tube 1 is placed on the cover plate 71 and the crucible 9 is moved to determine the crystal seeding crucible position based on the position of the guide tube 1. However, since the insulation layer 7 will expand and deform, causing the position of the guide tube 1 to change, the position of the liquid surface changes relative to the position of the guide tube 1, affecting the control of the diameter, temperature, and pulling speed of each furnace, and further affecting the quality of the crystal rod. In this embodiment, the limitation of the position of the guide tube 1 by the thermal insulation layer 7 is broken, and the lifting and lowering of the guide tube 1 is controlled by the lifting structure of the guide tube 1, so that there is always a gap between the guide tube 1 and the thermal insulation layer 7 in the axial direction of the furnace body 10. In this way, even if the thermal insulation layer 7 is deformed, it will not affect the position of the guide tube 1, and the liquid level position of the silicon melt will not change relative to the position of the guide tube 1, thereby ensuring the stability of the relative position relationship between the liquid level position and the heater structure 101, thereby saving the time for stable temperature testing and improving the quality of the crystal rod.

[0051] And because the crystal growth device in this embodiment makes the guide tube 1 free from the limitation of the position of the guide tube 1 by the cover plate 71, when adjusting the liquid level spacing and determining the position of the crystal induction crucible, the guide tube 1 can be adjusted to the preset position first, and then the position of the crucible 9 can be adjusted relative to the position of the guide tube 1 according to the required liquid level spacing. Alternatively, the crucible 9 can be moved to a preset position first, and then the position of the guide tube 1 can be adjusted relative to the position of the crucible 9 according to the required liquid level spacing. The adjustment is relatively flexible.

[0052] In an exemplary embodiment, the furnace body 10 includes a furnace cover 8, and the lifting structure of the guide tube 1 includes a lifting rod 2 and a lifting unit 3 for controlling the lifting of the lifting rod 2, and the lifting rod 2 passes through the furnace cover 8 and is connected to the guide tube 1.

[0053] Exemplarily, the lifting unit 3 includes a lead screw 31 and a drive motor 32;

[0054] The lifting rod 2 is bolted to the lead screw 31 through a connecting block 4, one end of the connecting block 4 is fixedly connected to the end of the lifting rod 2 away from the guide tube 1, and the other end of the connecting block 4 is provided with a connecting hole, the inner wall of which is provided with an internal thread, and the connecting hole is spirally connected to the lead screw 31;

[0055] The driving motor 32 is used to drive the screw 31 to rotate so as to control the lifting rod 2 to move along the screw 31 so as to drive the guide tube 1 to move up and down.

[0056] In an exemplary embodiment, the crystal growth device further includes a scale 5 fixed on the furnace cover 8, the scale 5 is located on one side of the lifting rod 2, and the scale values ​​on the scale 5 are set along the lifting direction of the guide tube 1;

[0057] A pointing block is provided on one side of the lifting rod 2 facing the scale 5 .

[0058] Exemplarily, the connection block 4 can be reused as the pointing block to simplify the structure.

[0059] When determining the crystal seeding crucible position, first raise the crucible 9 to a preset position, then adjust the position of the guide tube 1 so that the protruding part of the probe 11 at one end of the guide tube 1 contacts the liquid surface of the silicon melt, and then the first scale value can be recorded; then the distance that the guide tube 1 needs to move is obtained according to the required liquid level spacing, and the guide tube 1 is moved to the second position according to this distance, and the second scale value can be measured at this time. Through the setting of the scale 5, the guide tube 1 can be moved intuitively. And the second scale value can be set as a standard value. Under the same crystal pulling process conditions (including the seeding conditions of the same amount of silicon material, etc.), the position of the guide tube 1 can be directly adjusted to the position corresponding to the second scale value, saving processes and improving efficiency.

[0060] In an exemplary embodiment, the insulation layer 7 is provided in a cylindrical shape, and a gap is provided between one end of the insulation layer 7 close to the top of the furnace body 10 and one end of the guide tube 1 close to the top of the furnace body 10. The existence of the gap ensures that the position of the guide tube 1 is not affected by the deformation of the insulation layer 7.

[0061] In an exemplary embodiment, a wind shield 12 is provided at one end of the guide tube 1 close to the top of the furnace body 10. In the radial direction of the furnace body 10, part of the wind shield 12 extends to above the insulation layer 7 to shield part of the insulation layer 7, and there is a gap between the wind shield 12 and the insulation layer 7.

[0062] It should be noted that, in some embodiments, a cover plate 71 is provided at one end of the insulation layer 7 close to the top of the furnace body 10, and there is a gap between the guide tube 1 and the insulation layer 7, which means that there is a gap between the guide tube 1 and the cover plate 71, and the wind shield 12 also blocks the cover plate 71.

[0063] The guide tube 1 is usually an inverted cone shield made of graphite material, which is used to adjust the flow direction and flow rate of argon gas, so that the downward blowing argon gas is concentrated near the growth interface of the crystal, and to prevent the high-temperature liquid surface and the crucible 9 from transmitting heat radiation to the cooling crystal, thereby increasing the heat output of the crystal surface to the surroundings, and increasing the heat transfer rate on the crystal side and the temperature gradient on the crystal side. In the conventional technology, the guide tube 1 is supported on the insulation layer 7. In this embodiment, the guide tube 1 is separated from the insulation layer 7, so that there is a gap between the guide tube 1 and the insulation layer 7. In order to prevent argon gas from entering the gap and affecting the growth quality of the crystal, a windshield 12 is provided to shield the gap between the guide tube 1 and the insulation layer 7.

[0064] Exemplarily, the guide tube 1 is in a cylindrical shape, and the wind shield is an annular structure arranged on the top of the guide tube 1.

[0065] refer to Figure 1 and 2 , exemplarily, the wind shield 12 is an annular planar structure.

[0066] refer to Figure 3 In an exemplary embodiment, the cross-sectional shape of the wind shield 12 in the axial direction of the furnace body 10 is Z-shaped, and the wind shield 12 includes a first portion 121 connected to the guide tube 1, a second portion 122 located above the insulation layer 7, and a third portion 123 located between the first portion 121 and the second portion 122, and the first portion 121 and the second portion 122 are arranged in parallel.

[0067] The Z-shaped setting makes it possible for the distance between the second part 122 and the bottom of the furnace body 10 to be greater than the distance between the first part 121 and the bottom of the furnace body 10 in the axial direction of the furnace body 10, thereby increasing the distance between the second part 122 and the insulation layer 7 and effectively avoiding contact between the guide tube 1 and the insulation layer 7.

[0068] In an exemplary embodiment, the orthographic projection of the wind shield 12 on the insulation layer 7 covers a first area at the top of the insulation layer 7 , and the first area sinks toward the bottom of the furnace body 10 to form a groove 711 .

[0069] The arrangement of the groove 711 effectively prevents the guide tube 1 from contacting the thermal insulation layer 7 , thereby ensuring the existence of a gap between the thermal insulation layer 7 and the guide tube 1 in the axial direction of the furnace body 10 .

[0070] refer to Figure 4 The embodiment of the present invention further provides a method for determining the seeding crucible position, which is determined by using the above-mentioned crystal growth device, and includes the following steps:

[0071] After the material is oxidized, the guide tube 1 and / or the crucible 9 are controlled to move up and down, so that the probe 11 at one end of the guide tube 1 close to the bottom of the furnace body 10 contacts the silicon melt, wherein there is a gap between the guide tube 1 and the insulation layer;

[0072] The distance that the guide tube 1 or the crucible 9 needs to be raised or lowered is determined according to the preset liquid level interval, and the guide tube 1 or the crucible 9 is controlled to be raised or lowered according to the distance to determine the seeding crucible position.

[0073] Through the crystal growth device in this embodiment, the guide tube 1 is freed from the limitation of the insulation layer 7, so that when the liquid level spacing is adjusted, at least one of the guide tube 1 and the crucible 9 can be moved to ensure the stability of the liquid level position of the silicon solution, avoid changes in the distance between the liquid surface and the guide tube 1, and further avoid changes in the relative position relationship between the liquid surface and the heater structure.

[0074] It should be noted that the distance that the guide tube 1 or the crucible 9 needs to be raised or lowered is determined according to the preset liquid level spacing. Specifically, the distance that the guide tube 1 or the crucible 9 needs to be raised or lowered is the difference between the preset liquid level spacing and the length of the protruding portion of the probe 11. The protruding portion of the probe 11 refers to the portion of the probe 11 exposed from the guide tube 1.

[0075] In an exemplary embodiment, the furnace body 10 includes a furnace cover 8, and the guide tube lifting structure includes a lifting rod 2 and a lifting unit 3 for controlling the lifting of the lifting rod 2, wherein the lifting rod 2 passes through the furnace cover 8 and is connected to the guide tube 1; the lifting unit 3 includes a lead screw 31 and a drive motor 32;

[0076] The lifting rod 2 is bolted to the lead screw 31 via a connecting block 4;

[0077] The driving motor 32 is used to drive the screw 31 to rotate so as to control the lifting rod 2 to move along the screw 31 so as to drive the guide tube 1 to rise and fall;

[0078] The crystal growth device further includes a scale 5 fixed on the furnace cover 8, the scale 5 is located on one side of the lifting rod 2, and the scale values ​​on the scale 5 are set along the lifting direction of the guide tube 1;

[0079] A pointing block is provided on one side of the lifting rod 2 facing the scale 5;

[0080] The method for determining the seeding crucible position comprises the following steps:

[0081] After the material is oxidized, the crucible 9 is controlled to rise to a preset position (which can be set according to actual needs);

[0082] Control the guide tube 1 to descend until the probe 11 at one end of the guide tube 1 close to the bottom of the furnace body 10 contacts the silicon melt, and record the current scale value;

[0083] The distance that the guide tube 1 needs to rise is determined according to the preset liquid level spacing, and the rise of the guide tube 1 is controlled according to the distance, and the scale value (defined as the first scale value) after the guide tube 1 rises is recorded, and the position of the scale value is used as the standard position of the guide tube 1 under the same process conditions.

[0084] Through the setting of the structure such as the scale 5, the first scale value corresponding to the position of the guide tube 1 can be used as a standard value when determining the crystal pulling crucible position. When performing crystal pulling setting under the same process conditions, after moving the crucible 9 to the preset position, the guide tube 1 can be directly moved to the position corresponding to the first scale value. This is simple and fast, and the efficiency is improved.

[0085] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A crystal growth device, It is characterized in that include: Furnace body; A crucible, disposed inside the furnace body, for containing molten silicon; A heater structure is disposed around the periphery of the crucible to heat the crucible; A heat-insulating layer is disposed on the periphery of the heater structure; A guide tube is vertically arranged above the silicon melt in the furnace body; A guide tube lifting structure is arranged on the top of the furnace body, and is used to control the lifting and lowering of the guide tube, so that there is always a gap between the guide tube and the insulation layer along the axial direction of the furnace body; A cover plate is arranged at one end of the heat-insulating layer close to the top of the furnace body, and there is always a gap between the guide tube and the cover plate.

2. The crystal growth apparatus according to claim 1, It is characterized in that The furnace body includes a furnace cover, and the guide tube lifting structure includes a lifting rod and a lifting unit for controlling the lifting of the lifting rod. The lifting rod passes through the furnace cover and is connected to the guide tube.

3. The crystal growth apparatus according to claim 2, It is characterized in that The lifting unit includes a lead screw and a drive motor; The lifting rod is connected to the lead screw via a connecting block bolt; The driving motor is used to drive the lead screw to rotate so as to control the lifting rod to move along the lead screw so as to drive the guide cylinder to rise and fall.

4. The crystal growth apparatus according to claim 3, It is characterized in that It also includes a scale fixed on the furnace cover, the scale is located on one side of the lifting rod, and the scale values ​​on the scale are set along the lifting direction of the guide tube; A pointing block is arranged on one side of the lifting rod facing the scale.

5. The crystal growth apparatus according to claim 1, It is characterized in that A windshield is provided at one end of the guide tube close to the top of the furnace body. In the radial direction of the furnace body, part of the windshield extends above the insulation layer to shield part of the insulation layer, and there is a gap between the windshield and the insulation layer.

6. The crystal growth apparatus according to claim 5, It is characterized in that The cross-sectional shape of the wind shield in the axial direction of the furnace body is Z-shaped; The wind shield includes a first part connected to the guide tube, a second part located above the thermal insulation layer, and a third part located between the first part and the second part, and the first part and the second part are arranged in parallel.

7. The crystal growth apparatus according to claim 5, It is characterized in that The orthographic projection of the wind shield on the heat-insulating layer covers a first area at the top of the heat-insulating layer, and the first area sinks toward the bottom of the furnace body to form a groove.

8. A method for determining the position of the seeding crucible, It is characterized in that The determination is performed using the crystal growth apparatus according to any one of claims 1 to 7, comprising the following steps: After the material is oxidized, the guide tube and / or the crucible are controlled to move up and down so that the probe at one end of the guide tube close to the bottom of the furnace body contacts the silicon melt; Determine the distance that the guide tube or the crucible needs to be raised or lowered according to the preset liquid level interval, and control the guide tube or the crucible to be raised or lowered according to the distance to determine the seeding crucible position; There is always a gap between the guide tube and the insulation layer along the axial direction of the furnace body.

9. The method for determining the seeding crucible position according to claim 8, It is characterized in that The furnace body includes a furnace cover, the guide tube lifting structure includes a lifting rod and a lifting unit for controlling the lifting of the lifting rod, and the lifting rod passes through the furnace cover and is connected to the guide tube; The lifting unit includes a lead screw and a drive motor; The lifting rod is connected to the lead screw via a connecting block bolt; The driving motor is used to drive the lead screw to rotate so as to control the lifting rod to move along the lead screw so as to drive the guide cylinder to rise and fall; The crystal growth device further comprises a scale fixed on the furnace cover, the scale is located on one side of the lifting rod, and the scale values ​​on the scale are arranged along the lifting direction of the guide tube; A pointing block is provided on one side of the lifting rod facing the scale; The method for determining the seeding crucible position comprises the following steps: After the material is oxidized, the crucible is controlled to rise to the preset position; Control the guide tube to descend until the probe at one end of the guide tube close to the bottom of the furnace body contacts the silicon melt, and record the current scale value; The distance that the guide tube needs to rise is determined according to the preset liquid level spacing, and the rise of the guide tube is controlled according to the distance, and the scale value after the guide tube rises is recorded, and the position of the scale value is used as the standard position of the guide tube under the same process conditions.

Images