Single crystal furnace, single crystal furnace melt gap measurement method and single crystal furnace silicon leakage detection method

Abstract

The invention provides a single crystal furnace, a single crystal furnace melt gap measurement method and a single crystal furnace silicon leakage detection method, the single crystal furnace comprises a furnace body, a crucible assembly, at least one distance measurement unit and a heat shield; the crucible assembly is arranged at the bottom of the furnace body and is used for bearing silicon melt; the heat shield is located in the furnace body and arranged above the crucible assembly, the heat shield is in a hollow ring shape, and the heat shield and the crucible assembly are coaxial; and the distance measuring unit is arranged above the crucible assembly and is used for measuring a first distance from the distance measuring unit to the liquid level of the silicon melt. According to the scheme provided by the invention, the liquid level of the silicon melt in the crucible assembly can be accurately measured, so that the melt gap between the liquid level of the silicon melt and the bottom of the heat shield can be determined, the influence of air inflation and deflation and strong light of the liquid level of the silicon melt is avoided, the instability of the liquid level of the silicon melt can be found in time, and the quality of a single crystal is improved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor processing, and in particular to a single crystal furnace, a single crystal furnace melt gap measurement method and a single crystal furnace silicon leakage detection method. Background Art

[0002] In the production process of single crystal silicon, the liquid level monitoring curve of the silicon melt usually jumps back and forth within a certain range, and real-time monitoring is required to confirm whether the liquid level of the silicon melt is within the normal range, so as to avoid the unstable liquid level of the silicon melt causing the instability of the gap with the heat shield, thereby avoiding the unstable temperature gradient caused by the unstable gap affecting the quality of the single crystal. When the silicon material is in a molten state, the melt itself will produce strong light, and it will be affected by factors such as argon filling and degassing, crucible rotation, etc., so that the melt surface will fluctuate, which makes the melt gap monitoring method based on image processing have a large error. As a result, the liquid level of the silicon melt cannot be accurately monitored, which is easy to cause changes in the melt gap, thereby affecting the quality of the single crystal. Summary of the invention

[0003] The embodiments of the present invention provide a single crystal furnace, a single crystal furnace melt gap measurement method and a single crystal furnace silicon leakage detection method, which are used to solve the problem in the prior art that the liquid level of the silicon melt cannot be accurately monitored, which easily causes changes in the melt gap and thus affects the quality of the single crystal.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] In a first aspect, an embodiment of the present invention provides a single crystal furnace, comprising:

[0006] a furnace body, a crucible assembly, at least one distance measuring unit, and a heat shield;

[0007] The crucible assembly is arranged at the bottom of the furnace body and is used to carry the silicon melt;

[0008] The heat shield is located in the furnace body and is arranged above the crucible assembly. The heat shield is a hollow ring and is coaxial with the crucible assembly.

[0009] The distance measuring unit is disposed above the crucible assembly and is used to measure a first distance from the distance measuring unit to a liquid surface of the silicon melt.

[0010] Furthermore, the single crystal furnace further comprises:

[0011] A pulling head, the pulling head is located in the furnace body and arranged above the crucible assembly;

[0012] At least one of the distance measuring units is evenly arranged on a first plane, and the first plane is a plane perpendicular to the axis of the pulling head.

[0013] Furthermore, the distance measurement unit comprises:

[0014] Signal transmitter and signal receiver;

[0015] The signal transmitter is used to transmit a measurement signal to the silicon melt;

[0016] The signal receiver is used to receive the measurement signal reflected by the silicon melt, and determine the first distance according to the received measurement signal.

[0017] Furthermore, the crucible assembly comprises:

[0018] Crucible trays, quartz crucibles and graphite crucibles;

[0019] The crucible tray is arranged at the bottom of the furnace body;

[0020] The quartz crucible is placed in the graphite crucible and supported by the crucible tray.

[0021] Furthermore, the single crystal furnace further comprises:

[0022] Multiple temperature sensors;

[0023] A plurality of temperature sensors are arranged in a ring shape on the lifting head;

[0024] Wherein, the diameter of the circular ring formed by the plurality of temperature sensors is smaller than the radius of the pulling head.

[0025] In a second aspect, an embodiment of the present invention provides a single crystal furnace melt gap measurement method, which is applied to the single crystal furnace as described above, comprising:

[0026] Acquire a first distance collected by the distance measurement unit;

[0027] Determining a second distance from the distance measuring unit to the bottom of the heat shield according to the setting height of the distance measuring unit in the furnace body and the setting height of the heat shield;

[0028] According to the first distance and the second distance, the distance from the bottom of the heat shield to the surface of the molten silicon is determined as the melt gap.

[0029] Furthermore, the first distance collected by the distance measurement unit includes:

[0030] Determining the first time when the signal transmitter transmits the measurement signal;

[0031] determining a second time at which the signal receiver receives the measurement signal;

[0032] The first distance is determined according to the first time and the second time.

[0033] In a third aspect, an embodiment of the present invention provides a single crystal furnace silicon leakage detection method, which is applied to the single crystal furnace as described above, comprising:

[0034] Acquire a first distance collected by the distance measurement unit;

[0035] Whether silicon leakage occurs in the single crystal furnace is determined according to the first distance and the target height of the silicon melt level.

[0036] Furthermore, the first distance collected by the distance measurement unit includes:

[0037] Determining the first time when the signal transmitter transmits the measurement signal;

[0038] determining a second time at which the signal receiver receives the measurement signal;

[0039] The first distance is determined according to the first time and the second time.

[0040] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the single crystal furnace melt gap measurement method as described above; or, when executed by a processor, implements the steps of the single crystal furnace silicon leakage detection method as described above.

[0041] The beneficial effects of the present invention are:

[0042] The single crystal furnace of the embodiment of the present invention can accurately measure the liquid level of the silicon melt in the crucible assembly through the distance measuring unit arranged above the crucible assembly, so as to determine the melt gap between the liquid level of the silicon melt and the bottom of the heat shield, and is not affected by the filling and releasing of gas and the strong bright light on the silicon melt surface. The instability of the silicon melt liquid level height can be detected in time, thereby improving the quality of the single crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram showing the structure of a single crystal furnace according to an embodiment of the present invention;

[0044] Figure 2 A schematic diagram showing the arrangement of a distance measuring unit on a lifting head according to an embodiment of the present invention;

[0045] Figure 3 A schematic diagram showing the steps of a method for measuring a melt gap in a single crystal furnace according to an embodiment of the present invention;

[0046] Figure 4 A schematic diagram showing the steps of a method for detecting silicon leakage in a single crystal furnace according to an embodiment of the present invention;

[0047] Figure 5 A schematic diagram showing a module of a single crystal furnace melt gap measuring device according to an embodiment of the present invention;

[0048] Figure 6 A schematic diagram of a device for detecting silicon leakage in a single crystal furnace according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail in conjunction with the accompanying drawings and specific embodiments. In the following description, specific details such as specific configurations and components are provided only to help fully understand the embodiments of the present invention. Therefore, it should be clear to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. In addition, for clarity and brevity, the description of known functions and structures is omitted.

[0050] It should be understood that the references to "one embodiment" or "an embodiment" throughout the specification mean that the specific features, structures, or characteristics associated with the embodiment are included in at least one embodiment of the present invention. Therefore, the references to "in one embodiment" or "in an embodiment" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0051] The present invention aims to solve the problem that the liquid level of silicon melt cannot be accurately monitored in the prior art, which easily causes changes in the melt gap and thus affects the quality of the single crystal. A single crystal furnace, a single crystal furnace melt gap measurement method and a single crystal furnace silicon leakage detection method are provided.

[0052] like Figure 1 to Figure 2 As shown, an embodiment of the present invention provides a single crystal furnace, comprising:

[0053] A furnace body 1, a crucible assembly 2, at least one distance measuring unit 3 and a heat shield 4;

[0054] The crucible assembly 2 is disposed at the bottom of the furnace body 1 and is used to carry molten silicon;

[0055] The heat shield 4 is located in the furnace body and is arranged above the crucible assembly 2. The heat shield 4 is hollow and annular, and the heat shield 4 is coaxial with the crucible assembly 2.

[0056] The distance measuring unit 3 is disposed above the crucible assembly 2 and is used to measure a first distance from the distance measuring unit 3 to a liquid surface A of the silicon melt.

[0057] Optionally, the furnace body comprises:

[0058] A main furnace body and an auxiliary furnace body connected to the main furnace body, wherein the main furnace body is arranged below the auxiliary furnace body;

[0059] The crucible assembly and the heat shield are arranged in the main furnace body, and the distance measuring unit is arranged in the auxiliary furnace body.

[0060] Optionally, the distance measuring unit is arranged on the top wall of the auxiliary furnace body.

[0061] Optionally, the diameter of the lower end of the heat shield is smaller than the diameter of the upper end of the heat shield;

[0062] The lower end of the heat shield is an end close to the silicon melt, and the upper end of the heat shield is an end away from the silicon melt.

[0063] The single crystal furnace of the embodiment of the present invention can accurately measure the liquid level of the silicon melt in the crucible assembly through the distance measuring unit arranged above the crucible assembly, so as to determine the melt gap between the liquid level of the silicon melt and the bottom of the heat shield, and is not affected by the filling and releasing of gas and the strong bright light on the silicon melt surface. The instability of the silicon melt liquid level height can be detected in time, thereby improving the quality of the single crystal.

[0064] Optionally, the single crystal furnace further comprises:

[0065] A lifting head 5, the lifting head 5 is located in the furnace body and is arranged above the crucible assembly 2;

[0066] At least one of the distance measuring units 3 is evenly arranged on a first plane, and the first plane is a plane perpendicular to the axis of the pulling head 5 .

[0067] The pulling head is used to control the solidification of the single crystal during the growth of the single crystal.

[0068] The single crystal furnace of the embodiment of the present invention can make the distance measuring unit perform measurement more accurately by evenly arranging the distance measuring unit on the pulling head, thereby improving the measurement accuracy of the melt gap.

[0069] Optionally, the distance measurement unit includes:

[0070] Signal transmitter and signal receiver;

[0071] The signal transmitter is used to transmit a measurement signal to the silicon melt;

[0072] The signal receiver is used to receive the measurement signal reflected by the silicon melt, and determine the first distance according to the received measurement signal.

[0073] Optionally, the signal transmitter includes:

[0074] Optical signal transmitter, acoustic signal transmitter and electrical signal transmitter.

[0075] Optionally, the signal receiver includes:

[0076] Optical signal receiver, acoustic signal receiver and electrical signal receiver.

[0077] In one embodiment of the present invention, the signal transmitter is an infrared signal transmitter, and the signal receiver is an infrared signal receiver.

[0078] Optionally, determining the first distance according to the received measurement signal includes:

[0079] According to a first time when the signal transmitter transmits the measurement signal, and a second time when the signal receiver receives the measurement signal;

[0080] Calculating a time difference between the second time and the first time;

[0081] determining a propagation speed of the measurement signal;

[0082] The first distance is calculated according to the propagation speed and the time difference.

[0083] Optionally, the crucible assembly comprises:

[0084] Crucible tray 6, quartz crucible and graphite crucible;

[0085] The crucible tray 6 is arranged at the bottom of the furnace body;

[0086] The quartz crucible is placed in the graphite crucible and supported by the crucible tray 6 .

[0087] Optionally, the single crystal furnace further includes:

[0088] A heating unit is disposed between the crucible assembly and the crucible tray; the heating unit is also disposed on the inner wall of the main furnace body.

[0089] Optionally, the single crystal furnace further comprises:

[0090] Multiple temperature sensors 7;

[0091] A plurality of temperature sensors 7 are arranged in a ring shape on the pulling head 5;

[0092] The diameter of the circular ring formed by the plurality of temperature sensors 7 is smaller than the radius of the pulling head 5 .

[0093] It should be noted that the diameter of the ring formed by the temperature sensor is determined according to the seeding diameter;

[0094] Specifically, the diameter of the ring formed by the temperature sensor is slightly larger than the seeding diameter.

[0095] In one embodiment of the present invention, the diameter of the ring formed by the temperature sensor is between 5 mm and 10 mm.

[0096] The single crystal furnace of the embodiment of the present invention can accurately monitor the temperature in the suitable temperature stage by providing the temperature sensor and making the diameter of the ring formed by the multiple temperature sensors smaller than the radius of the pulling head 5, so as to find the most stable seeding temperature.

[0097] like Figure 3 As shown, an embodiment of the present invention further provides a single crystal furnace melt gap measurement method, which is applied to the single crystal furnace as described above, and includes the following steps:

[0098] Step 301, obtaining a first distance collected by the distance measurement unit;

[0099] Step 302, determining a second distance from the distance measurement unit to the bottom of the heat shield according to the installation height of the distance measurement unit in the furnace body and the installation height of the heat shield;

[0100] Step 303: Determine, according to the first distance and the second distance, the distance from the bottom of the heat shield to the surface of the molten silicon as the melt gap.

[0101] The single crystal furnace melt gap measurement method of the embodiment of the present invention can accurately measure the liquid level of the silicon melt in the crucible assembly through the distance measurement unit arranged above the crucible assembly, so as to determine the melt gap between the silicon melt liquid level and the bottom of the heat shield, and is not affected by the filling and releasing of gas and the strong bright light on the silicon melt liquid surface. It can accurately measure the melt gap and timely discover the instability of the silicon melt liquid level height, thereby improving the quality of the single crystal.

[0102] Optionally, the first distance collected by the distance measurement unit includes:

[0103] Determining the first time when the signal transmitter transmits the measurement signal;

[0104] determining a second time at which the signal receiver receives the measurement signal;

[0105] The first distance is determined according to the first time and the second time.

[0106] Optionally, determining the first distance according to the first time and the second time includes:

[0107] Calculating a time difference between the second time and the first time;

[0108] determining a propagation speed of the measurement signal;

[0109] The first distance is calculated according to the propagation speed and the time difference.

[0110] Specifically, the first distance is the product of the propagation speed and the time difference.

[0111] like Figure 4 As shown, an embodiment of the present invention further provides a single crystal furnace silicon leakage detection method, which is applied to the single crystal furnace as described above, and includes the following steps:

[0112] Step 401, obtaining a first distance collected by the distance measurement unit;

[0113] Step 402: Determine whether silicon leakage occurs in the single crystal furnace based on the first distance and the target height of the silicon melt level.

[0114] It should be noted that the first distance is the distance from the distance measurement unit to the surface of the silicon melt;

[0115] When the target height of the silicon melt level is determined, the first distance is a determined value;

[0116] When the first distance increases, it can be determined that silicon leakage occurs in the single crystal furnace; when the first distance does not change, it is determined that silicon leakage does not occur in the single crystal furnace.

[0117] In the embodiment of the present invention, when the change in the first distance is greater than a preset threshold, it is determined that silicon leakage occurs in the single crystal furnace;

[0118] When the change in the first distance is less than or equal to the preset threshold, it is determined that no silicon leakage occurs in the single crystal furnace.

[0119] The single crystal furnace silicon leakage detection method of the embodiment of the present invention can accurately determine whether the single crystal furnace has silicon leakage by measuring the change in the silicon melt liquid level through the distance measurement unit, so that the staff can respond quickly to avoid greater production losses.

[0120] Optionally, the first distance collected by the distance measurement unit includes:

[0121] Determining the first time when the signal transmitter transmits the measurement signal;

[0122] determining a second time at which the signal receiver receives the measurement signal;

[0123] The first distance is determined according to the first time and the second time.

[0124] Optionally, determining the first distance according to the first time and the second time includes:

[0125] Calculating a time difference between the second time and the first time;

[0126] determining a propagation speed of the measurement signal;

[0127] The first distance is calculated according to the propagation speed and the time difference.

[0128] like Figure 5 As shown, the embodiment of the present invention further provides a single crystal furnace melt gap measuring device 500, comprising:

[0129] A first acquisition module 501, configured to acquire a first distance collected by the distance measurement unit;

[0130] A first determining module 502 is used to determine a second distance from the distance measuring unit to the bottom of the heat shield according to the setting height of the distance measuring unit in the furnace body and the setting height of the heat shield;

[0131] The second determination module 503 is used to determine the distance from the bottom of the heat shield to the surface of the molten silicon as the melt gap according to the first distance and the second distance.

[0132] The single crystal furnace melt gap measuring device of the embodiment of the present invention can accurately measure the liquid level of the silicon melt in the crucible assembly through the distance measuring unit arranged above the crucible assembly, so as to determine the melt gap between the silicon melt liquid level and the bottom of the heat shield, and is not affected by the filling and releasing of gas and the strong bright light on the silicon melt liquid surface. It can accurately measure the melt gap and promptly detect the instability of the silicon melt liquid level height, thereby improving the quality of the single crystal.

[0133] like Figure 6 As shown, the embodiment of the present invention further provides a single crystal furnace silicon leakage detection device 600, comprising:

[0134] A second acquisition module 601 is used to acquire a first distance collected by the distance measurement unit;

[0135] The judgment module 602 is used to judge whether silicon leakage occurs in the single crystal furnace according to the first distance and the target height of the silicon melt liquid level.

[0136] The single crystal furnace silicon leakage detection device of the embodiment of the present invention can accurately determine whether the single crystal furnace has silicon leakage by measuring the change in the silicon melt level through the distance measurement unit, so that the staff can respond quickly and avoid greater production losses.

[0137] In addition, a specific embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the single crystal furnace melt gap measurement method described above are implemented; or, when the computer program is executed by a processor, the steps of the single crystal furnace silicon leakage detection method described above are implemented. And the same technical effect can be achieved, and to avoid repetition, it will not be repeated here.

[0138] The embodiment of the present application also provides a computer program product, including computer instructions, which, when executed by a processor, implement each process of the above-mentioned single crystal furnace melt gap measurement method embodiment; or, when executed by a processor, implement each process of the above-mentioned single crystal furnace silicon leakage detection method embodiment. And can achieve the same technical effect, to avoid repetition, it will not be repeated here.

[0139] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary personnel in this technical field, several improvements and modifications can be made without departing from the principles described in the present invention. These improvements and modifications are also within the scope of protection of the present invention.

Claims

1. A single crystal furnace, characterized in that: include: a furnace body, a crucible assembly, at least one distance measuring unit, and a heat shield; The crucible assembly is arranged at the bottom of the furnace body and is used to carry the silicon melt; The heat shield is located in the furnace body and is arranged above the crucible assembly. The heat shield is a hollow ring and is coaxial with the crucible assembly. The distance measuring unit is disposed above the crucible assembly and is used to measure a first distance from the distance measuring unit to a liquid surface of the silicon melt.

2. The single crystal furnace according to claim 1, characterized in that: Also includes: A pulling head, the pulling head is located in the furnace body and arranged above the crucible assembly; At least one of the distance measuring units is evenly arranged on a first plane, and the first plane is a plane perpendicular to the axis of the pulling head.

3. The single crystal furnace according to claim 1 or 2, characterized in that: The distance measuring unit comprises: Signal transmitter and signal receiver; The signal transmitter is used to transmit a measurement signal to the silicon melt; The signal receiver is used to receive the measurement signal reflected by the silicon melt, and determine the first distance according to the received measurement signal.

4. The single crystal furnace according to claim 1, characterized in that: The crucible assembly comprises: Crucible trays, quartz crucibles and graphite crucibles; The crucible tray is arranged at the bottom of the furnace body; The quartz crucible is placed in the graphite crucible and supported by the crucible tray.

5. The single crystal furnace according to claim 2, characterized in that: Also includes: Multiple temperature sensors; A plurality of temperature sensors are arranged in a ring shape on the lifting head; Wherein, the diameter of the circular ring formed by the plurality of temperature sensors is smaller than the radius of the pulling head.

6. A method for measuring the gap between melt and single crystal furnace, characterized in that: The single crystal furnace according to any one of claims 1 to 5 comprises: Acquire a first distance collected by the distance measurement unit; Determining a second distance from the distance measuring unit to the bottom of the heat shield according to the setting height of the distance measuring unit in the furnace body and the setting height of the heat shield; According to the first distance and the second distance, the distance from the bottom of the heat shield to the surface of the molten silicon is determined as the melt gap.

7. The single crystal furnace melt gap measurement method according to claim 6, characterized in that: Applied to the single crystal furnace according to claim 3, the first distance collected by the distance measurement unit includes: Determining the first time when the signal transmitter transmits the measurement signal; determining a second time at which the signal receiver receives the measurement signal; The first distance is determined according to the first time and the second time.

8. A method for detecting silicon leakage in a single crystal furnace, characterized in that: The single crystal furnace according to any one of claims 1 to 5 comprises: Acquire a first distance collected by the distance measurement unit; Whether silicon leakage occurs in the single crystal furnace is determined according to the first distance and the target height of the silicon melt level.

9. The method for detecting silicon leakage in a single crystal furnace according to claim 8, characterized in that: Applied to the single crystal furnace according to claim 3, the first distance collected by the distance measurement unit includes: Determining the first time when the signal transmitter transmits the measurement signal; determining a second time at which the signal receiver receives the measurement signal; The first distance is determined according to the first time and the second time.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the single crystal furnace melt gap measurement method as described in claim 6 or 7 are implemented; or, when the computer program is executed by a processor, the steps of the single crystal furnace silicon leakage detection method as described in claim 8 or 9 are implemented.

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