Systems and methods for determining mechanical wear in crystal pullers

Abstract

A detection system includes a load meter connected to a gear of a crystal puller device and a motor to measure a force applied to the gear in the time domain. The data is analyzed by Fourier transform to obtain data in the frequency domain. The frequency domain data includes an amplitude corresponding to mechanical wear of the gear. The time-domain data is compared to a threshold amplitude to determine whether the gear has mechanical wear such that preventive maintenance can be performed on the electric machine.

Description

Technical Field

[0001] The present disclosure relates generally to the production of single crystal ingots, such as silicon ingots, and more particularly to methods and systems for determining mechanical wear in crystal puller components during production and without stopping the crystal puller. Background Art

[0002] The critical moving components in the crystal puller are responsible for the stable and controlled rotation and extraction of the crystal. Over time, and due to the heavy loads on the crystal puller components, the gears, bearings, pulleys and other components can become severely worn. If not properly monitored and maintained, the components may fail and critical functions in the crystal puller may be affected.

[0003] Service and maintenance of these components are often difficult because the components are inaccessible and downtime to visually inspect the components is costly and time consuming. By way of example, the pulling head of a crystal puller must be at least partially disassembled and each gear individually inspected for wear. Therefore, there is a need to monitor the components of a crystal puller and detect problems with these components without interrupting crystal growth operations before wear affects the performance of the crystal puller, crystal quality, and before catastrophic failure occurs.

[0004] This background section is intended to introduce the reader to various aspects of the technology that may be related to the various aspects of the present disclosure described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Therefore, it should be understood that these statements should be read in this light, and not as admissions of prior art. Summary of the invention

[0005] One aspect is a crystal pulling system comprising a crucible containing molten semiconductor material, a cable and a gear, a crystal disposed at one end of the cable during crystal pulling, and a motor for pulling the cable and crystal from the melt. A load cell is connected to the gear to measure the force applied to the gear, and a control system comprises a processor connected to the load cell. The processor is configured to process data received from the load cell and is configured to receive time domain data from the load cell within a measurement time during a crystal pulling process. The processor also transforms the time domain data into frequency domain data in a frequency domain, and the frequency domain data comprises a force-frequency amplitude within the measurement time. The processor determines whether the force-frequency amplitude has exceeded a threshold.

[0006] Another aspect is a detection system comprising a load cell connected to the gear to measure a force applied to the gear in a time domain, and a control system comprising a processor connected to the load cell. The control system is configured to process data received from the load cell, receive time domain data from the load cell within a measurement time during a crystal pulling process, and instruct to transform the time domain data into frequency domain data in the frequency domain. The frequency domain data comprises an amplitude within the measurement time, and the processor determines whether the amplitude has exceeded a threshold amplitude.

[0007] Another aspect is a method for detecting mechanical wear of a gear in a crystal puller. The method includes the steps of receiving time domain data from a load cell connected to the gear to measure a force applied to the gear in the time domain during a measurement time; transforming the time domain data into frequency domain data in the frequency domain, the frequency domain data including an amplitude during the measurement time; and determining whether the amplitude has exceeded a threshold amplitude.

[0008] There are various refinements of the features described in connection with the above aspects. Further features may also be incorporated into the above aspects. These refinements and additional features may exist individually or in any combination. For example, various features discussed below with respect to any of the illustrated embodiments may be incorporated into the above aspects individually or in any combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic diagram of an example ingot puller apparatus for pulling a single crystal silicon ingot from a silicon melt.

[0010] Figure 2 is a cross-sectional view of the ingot puller equipment.

[0011] Figure 3 is a partial view of an example single crystal silicon ingot grown by the Czochralski method.

[0012] Figure 4 It is a perspective view of a partial cross section of the pull-out mechanism.

[0013] Figure 5 is used for Figure 1 A block diagram of a computing device in a control system of an ingot puller apparatus.

[0014] Figure 6 is a flow chart showing the conversion of time domain data into frequency domain data.

[0015] Figure 7 is a graph of load cell data in the time domain for a motor having components with mechanical wear.

[0016] Figure 8 is a graph of load cell data in the frequency domain for a motor having components with mechanical wear.

[0017] Fig. 9 is a graph of load cell data in the frequency domain for a motor having components without mechanical wear.

[0018] Fig.10 Is a method for determining wear in an assembly of gears.

[0019] Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION

[0020] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 269,717, filed on March 22, 2022, the entirety of which is incorporated herein by reference.

[0021] Embodiments of the present disclosure relate to systems and methods for monitoring and analyzing selected signals recorded by a load cell in the frequency domain via a Fourier transform filter, such that characteristic signals associated with a failed component can be reliably distinguished from background noise and other ancillary signals. The analyzed signal is converted from the time domain to the frequency domain and compared to a threshold or predetermined limit to determine whether excessive wear has occurred in the gears or components of the crystal puller. The analyzed signal can facilitate the detection of periodic errors. For example, periodic errors can be attributed to vibration, eccentricity, or other mechanical irregularities in the gears, bearings, or shafts of the motor. Embodiments of the present disclosure can monitor conditions in a crystal puller without having to stop production, disassemble the crystal puller, or shut down the crystal puller for inspection. In addition, when excessive wear is determined, the crystal puller can be scheduled for maintenance without affecting the quality of the crystal and before a catastrophic failure that causes a loss of production crystals.

[0022] Will refer to Figures 1 to 4 An ingot puller apparatus (or more simply "ingot puller" or "crystal puller") for growing single crystal silicon ingots is described. Figure 1 and 2 1 is a schematic diagram of an ingot puller apparatus for pulling a single crystal silicon or semiconductor material ingot from a melt 104, indicated as a whole by "100". Figure 3 is a partial elevation view of a single crystal ingot grown by the Czochralski method, for example, in an ingot puller apparatus 100 . Figure 4 is a perspective view of the puller mechanism.

[0023] The ingot puller apparatus 100 includes a crystal puller housing 108 defining a growth chamber 152 for pulling a silicon ingot 113 from a silicon melt 104. A control system 170 controls the operation of the ingot puller apparatus 100 and its components, including one or more gears. The ingot puller apparatus 100 includes a crucible 102 disposed within the growth chamber 152 for holding the silicon melt 104. The crucible 102 is supported by a susceptor 106.

[0024] Crucible 102 includes a bottom 129 and a sidewall 131 extending upward from bottom 129. Sidewall 131 is generally vertical. Bottom 129 includes a curved portion of crucible 102 extending below sidewall 131. Within crucible 102 is a silicon melt 104 having a melt surface 111 (i.e., a melt-ingot interface). Susceptor 106 is supported by shaft 105. Susceptor 106, crucible 102, shaft 105, and ingot 113 have a common longitudinal axis A or "pulling axis" A.

[0025] A pulling mechanism 114 is disposed within the ingot puller apparatus 100 for growing and pulling an ingot 113 from the melt 104. The pulling mechanism 114 includes a pulling cable 118, a seed holder or clamp 120 coupled to one end of the pulling cable 118, and a seed 122 coupled to the seed holder or clamp 120 for initiating crystal growth. One end of the pulling cable 118 is connected to a pulley or roller 117, or any other suitable type of lifting mechanism, such as a shaft, and the other end is connected to the clamp 120 that holds the seed 122. In operation, the seed 122 is lowered to contact the melt 104. The pulling mechanism 114 is operated to cause the seed 122 to rise. This causes the single crystal ingot 113 to be pulled out from the melt 104.

[0026] During heating and crystal pulling, a crucible drive unit 107 (e.g., a motor) rotates the crucible 102 and susceptor 106. During the growth process, a crucible elevator 112 mechanism raises and lowers the crucible 102 along the pull axis A. As the ingot grows, the silicon melt 104 is consumed and the height of the melt in the crucible 102 decreases. The crucible 102 and susceptor 106 may be raised to maintain the melt surface 111 at the same or nearly the same position relative to the ingot puller apparatus 100.

[0027] The crucible drive unit 107 can raise or lower the crucible 102 via the worm gear 109 (one of the components that are subject to wear). A load cell 192 is suitably connected to the worm gear 109 or the crucible drive unit 107 to measure the force applied to the worm gear 109. The load cell 192 is suitably a force transducer, but may be another type of sensor. The worm gear 109 is connected in series to a rotor (not shown) of the crucible drive unit 107 via a gear or shaft (not shown). The crucible drive unit 107 may include a bearing (not shown) that supports the shaft. As used herein, the term "series-connected gears" shall refer to a gear train of a mechanical system formed by a combination of gears connected to other gears (i.e., a gear tooth of a first gear connected to a gear tooth of a second gear) and gears coupled to other gears, for example, via a rotating shaft. The load cell 192 is positioned within the motor and is in situ with the system. Thus, the load cell 192 can be positioned within the motor housing without having to install external components.

[0028] like Figure 1 and 4, the crystal drive unit 180 (e.g., a motor) can also rotate the pull-out cable 118 and the ingot 113 in a direction opposite to the direction in which the crucible drive unit 107 rotates the crucible 102 (e.g., counter-rotation). In embodiments using co-rotation, the crystal drive unit can rotate the pull-out cable 118 in the same direction in which the crucible drive unit 107 rotates the crucible 102. In addition, the crystal drive unit raises and lowers the ingot 113 relative to the melt surface 111 as needed during the growth process.

[0029] The crystal drive unit 180 includes a rotor 182 connected to a cable winding drum 184 through one or more gears 185 and shafts 186. The drum 184, gears 185, and shafts 186 are connected in series. The cable 118 is wound around the drum 184 and then suspended from a pulley 188. In some embodiments, a load cell 194 is a force transducer. In some embodiments, the load cell 194 is coupled to the pulley 188 by a load cell link or anchor 190 opposite the gears. The gears 185 and shafts 186 of the rotor 182 are supported by bearings (not shown).

[0030] The ingot puller apparatus 100 may include an inert gas system to introduce and extract an inert gas, such as argon, from the growth chamber 152. The ingot puller apparatus 100 may also include a dopant feed system (not shown) for introducing dopants into the melt 104.

[0031] According to the Czochralski single crystal growth process, a certain amount of polycrystalline silicon (polycrystalline silicon or polysilicon) is charged into the crucible 102 (for example, 250 kg or more is charged). A variety of polycrystalline silicon sources can be used, for example, granular polycrystalline silicon produced by thermal decomposition of silane or halosilane in a fluidized bed reactor, or polycrystalline silicon produced in a Siemens reactor. Once the polycrystalline silicon is added to the crucible to form a charge, the charge is heated to a temperature approximately above the melting temperature of silicon (for example, approximately 1412° C.) to melt the charge. In some embodiments, the charge (i.e., the resulting melt) is heated to a temperature of at least about 1425° C., at least about 1450° C., or even to a temperature of at least about 1500° C. The ingot puller apparatus 100 includes a bottom insulator 110 and a side insulator 124 to retain heat in the puller apparatus 100. In the illustrated embodiment, the ingot puller apparatus 100 includes a bottom heater 126 disposed below the bottom 129 of the crucible. The crucible 102 may be moved to a position relatively close to the bottom heater 126 to melt the polycrystalline body loaded into the crucible 102 .

[0032] To form an ingot, a seed crystal 122 is contacted with a surface 111 of a melt 104. A pulling mechanism 114 is operated to pull the seed crystal 122 from the melt 104. The ingot 113 includes a crown 142 in which the ingot transitions outwardly from the seed crystal 122 and tapers to reach a target diameter. The ingot 113 includes a constant diameter portion or cylindrical body 145 of the crystal grown by increasing the pulling rate. The body 145 of the ingot 113 has a relatively constant diameter. The ingot 113 includes a tail or end cone (not shown) in which the ingot tapers in diameter after the body 145. When the diameter becomes sufficiently small, the ingot 113 is then separated from the melt 104. The ingot 113 has a central longitudinal axis A extending through the crown 142 and the terminal end of the ingot 113.

[0033] The ingot puller apparatus 100 includes side heaters 135 and susceptors 106 that surround the crucible 102 to maintain the temperature of the melt 104 during crystal growth. The side heaters 135 are disposed radially outward to the crucible sidewall 131 as the crucible 102 moves up and down along the pull axis A. The side heaters 135 and the bottom heater 126 can be any type of heater that allows the side heaters 135 and the bottom heater 126 to operate as described herein. In some embodiments, the heaters 135, 126 are resistive heaters. The side heaters 135 and the bottom heater 126 can be controlled by a control system 170 so that the temperature of the melt 104 is controlled throughout the pulling process.

[0034] The ingot puller apparatus 100 also includes a reflector 151 (or "heat shield") disposed within the growth chamber 152 and above the melt 104, covering the ingot 113 during ingot growth. During crystal growth, the reflector 151 may be partially disposed within the crucible 102. The reflector 151 defines a central passage 160 for receiving the ingot 113 as it is pulled by the pulling mechanism 114.

[0035] The reflector 151 is typically a heat shield adapted to retain heat beneath it and above the melt 104. In this regard, any reflector design and material of construction known in the art (e.g., graphite or gray quartz) may be used without limitation.

[0036] Figure 3 1 shows a single crystal silicon ingot 113 produced according to an embodiment of the present disclosure and a typical Czochralski method. Ingot 113 includes a neck 116, a flared portion 142 (synonymous as "crown" or "cone"), a shoulder 119, and a constant diameter body 145. Neck 116 is attached to a seed crystal 122, which contacts the melt and is drawn out to form ingot 113. Body 145 is suspended from neck 116. Neck 116 terminates once the flared portion 142 of ingot 113 begins to form.

[0037] The constant diameter portion of ingot 113 has a circumferential edge 150, a central axis A parallel to circumferential edge 150, and a radius R extending from central axis A to the circumferential edge. Central axis A also passes through flared portion 142 and neck 116. The diameter of body 145 may vary, and in some embodiments, the diameter may be about 150 mm, about 200 mm, about 300 mm, greater than about 300 mm, about 450 mm, or even greater than about 450 mm.

[0038] The single crystal silicon ingot 113 may generally have any resistivity. The single crystal silicon ingot 113 may be doped or undoped.

[0039] The load meter 192 of the crucible drive unit 107 and the load meter 194 of the crystal drive unit 180 are part of a measuring system for measuring the loads of the crucible drive unit 107 and the crystal drive unit 180. In other words, the load meter 192 of the crucible drive unit 107 measures the weight of the crystal supported by the shaft 105, and the load meter 194 of the crystal drive unit 180 measures the weight of the crystal supported by the pull-out cable 118 of the crystal drive unit 180.

[0040] The rotation of the gears and shafts of the crucible drive unit 107 and the crystal drive unit 180 generates vibrations that can be detected and measured in the time domain by the load cells (192, 194). The data transmitted from the load cells (192, 194) can be collected by the control system 170, processed by the computing device 200 and transformed by an algorithm to obtain data in the frequency domain, as explained in further detail below, to determine whether the gears and bearings, or more generally the components of the motors of the crucible drive unit 107 and the crystal drive unit 180, are worn.

[0041] Figure 6 is an example computing device 200 that can be used as or as part of the control system 170. The computing device 200 is also used as a detection system. The computing device 200 includes a processor 202, a local memory 204, a communication interface 206, and a plurality of sensors 208. The plurality of sensors 208 includes a load cell (192, 194) connected to the processor 202. Other embodiments include different components, additional components, and / or do not include Figure 6 All components shown in .

[0042] The communication interface 206 and computing device 200 are connected to a programmable logic controller or "PLC" 174. The PLC 174 controls the operation of at least the motors and heaters (126, 135) of the crucible drive unit 107 and the crystal drive unit 180.

[0043] The processor 202 is configured to execute instructions. For example, executable instructions are stored in the memory 204, and the processor 202 may include one or more processing units (for example, in a multi-core configuration). One or more processing units appropriately perform the individual functions of the processor 202 and execute all or part of the instructions. The term processor used herein refers to a central processing unit, a microprocessor, a microcontroller, a reduced instruction set circuit (RISC), an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), and any other circuit or processor capable of performing the functions described herein. The above is only an example, and therefore it is not intended to limit the definition and / or meaning of the term "processor" in any way.

[0044] The local memory 204 stores non-temporary computer-readable instructions for executing the techniques described herein. When executed by the processor 202, such instructions cause the processor 202 to perform at least a portion of the methods described herein. In some embodiments, the memory 204 stores computer-readable instructions for providing a user interface to a user via a media output component, and receiving and processing input from an input device. The memory 204 may include, but is not limited to, a random access memory (RAM) such as a dynamic RAM (DRAM) or a static RAM (SRAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electronically erasable programmable read-only memory (EEPROM), and a non-volatile RAM (NVRAM). Although described as being separate from the processor 202, in some embodiments, the memory 204 is combined with the processor 202, such as in a microcontroller or a microprocessor, but may still be mentioned separately. The above memory types are examples only, and therefore do not limit the memory types that can be used to store computer programs.

[0045] In some embodiments, computing device 200 includes or is connected to an input device for receiving input from a user. An input device is any device that allows computing device 200 to receive analog and / or digital commands, instructions, or other input from a user, including visual, audio, touch, button presses, stylus taps, and the like. For example, an input device may include a variable resistor, an input dial, a keyboard / keypad, a pointing device, a mouse, a stylus, a touch-sensitive panel (e.g., a touch pad or touch screen), a gyroscope, an accelerometer, a position detector, an audio input device, or any combination thereof. A single component, such as a touch screen, may function as both an output device and an input device for a media output component.

[0046] The communication interface enables the computing device 200 to communicate with remote devices and systems forming the network 210, such as remote sensors, remote databases, remote computing devices, and the like, and may include more than one communication interface for interacting with more than one remote device or system. The communication interface may be a wired or wireless communication interface that allows the computing device 200 to communicate with remote devices and systems directly or via a network. The wireless communication interface may include a radio frequency (RF) transceiver, Adapter, Wi-Fi transceiver, The wired communication interface may include a wireless transceiver, a near field communication (NFC) transceiver, an infrared (IR) transceiver, and / or any other device and communication protocol for wireless communication. (Bluetooth is a registered trademark of the Bluetooth Special Interest Group of Kirkland, Washington; ZigBee is a registered trademark of the ZigBee Alliance of San Ramon, California.) The wired communication interface may use any suitable wired communication protocol for direct communication, including but not limited to USB, RS232, I2C, SPI, analog, and proprietary I / O protocols. In some embodiments, the wired communication interface includes a wired network adapter that allows the computing device 400 to couple to a network, such as the Internet, a local area network (LAN), a wide area network (WAN), a mesh network, and / or any other network, to communicate with remote devices and systems via the network 210.

[0047] Figure 6Flowchart 300 is illustrated for receiving data from load cells (192, 194) and processing the data by an algorithm to obtain output data, which is then compared to a configuration file stored in memory 204 to determine whether mechanical wear or failure has occurred on components of crucible drive unit 107 and crystal drive unit 180. Load cells (192, 194) transmit time domain data 302 to processor 202. In some embodiments, processor 202 may execute instructions to process time domain data 302 by an algorithm to convert time domain data 302 to frequency domain data 304. In some embodiments, processor 202 may execute instructions to send time domain data 302 to network 210 so that one or more processors of network 210 may execute instructions to process time domain data 302 by an algorithm to convert time domain data 302 to frequency domain data 304. Frequency domain data 304 is then compared to a configuration file 306 stored in memory 204 to determine whether mechanical wear or failure has occurred on components of crucible drive unit 107 and crystal drive unit 180. The configuration file 306 includes one or more thresholds that are compared to the frequency domain data 304. If the frequency domain data 304 is greater than the one or more thresholds, it is determined that mechanical wear or failure has occurred on the components of the crucible drive unit 107 and the crystal drive unit 180. As used herein, the terms "threshold" and "threshold value" refer to guard band limits in the frequency domain.

[0048] In some embodiments, the algorithm is a Fourier transform. In some embodiments, the algorithm is a fast Fourier transform. In some embodiments, the algorithm is a discrete Fourier transform. As used herein, the term "time domain data" refers to a mathematical function, physical signal, or time series of data relative to time. A time domain graph (e.g., Figure 7 As used herein, the term "frequency domain data" refers to mathematical functions and signals relative to frequency rather than time. Where a time domain plot illustrates a signal or data changing over time, a frequency domain plot (such as Figure 8 ) illustrates the amplitude of data or signals within a given frequency band over a frequency range.

[0049] Figure 7 The load cell data in the time domain is illustrated over a specific range of crystal growth length L. Figure 1, the crystal length L is the length of the constant diameter portion or cylindrical body 145. In other words, the crystal length L is from the melt surface 111. The load cell data in the time domain is collected over a period T (or more generally, a measurement time) where the ingot 113 has a crystal length L of 1500 mm to 1700 mm, thereby defining the operating conditions of the control system 170 for determining mechanical wear. In some embodiments, the operating conditions (and time period T) include 100% of the crystal length L of the total crystal length. In some embodiments, the operating conditions (and time period T) include 80% of the crystal length L of the total crystal length. In some embodiments, the operating conditions (and time period T) include 60% of the crystal length L of the total crystal length. In some embodiments, the operating conditions (and time period T) include 40% of the crystal length L of the total crystal length. In some embodiments, the operating conditions (and time period T) include 20% of the crystal length L of the total crystal length.

[0050] In some embodiments, the processor 202 is configured to identify operating conditions of the processor 202 to receive time domain data from the load cell. In some embodiments, the processor is configured to receive time domain data throughout the crystal pulling process.

[0051] like Figure 7 1 , weight (in kg) fluctuations under operating conditions and thus over a period T are shown on components such as bearings, gears and worm gears of the crucible drive unit 107 and the crystal drive unit 180, or more generally, fluctuations in force data collected by load cells (192, 194) as illustrated by data (D1, D2, D3, D4). Data D1 and data D3 illustrate weight fluctuations of mechanically worn components of the crucible drive unit 107 and the crystal drive unit 180, data D2 illustrates weight fluctuations of maintained components of the crucible drive unit 107 and the crystal drive unit 180, and data D4 illustrates weight fluctuations of new and unworn components of the crucible drive unit 107 and the crystal drive unit 180. Weight fluctuations due to wear also cause vibrations, which are detected by the load cells (192, 194) under operating conditions. As the length of the ingot 113 grows, the vibrations and weight fluctuations gradually increase.

[0052] Weight fluctuations due to mechanical wear are difficult to detect in the time domain until the mechanical wear progresses close to failure. This is due to the lack of resolution and the presence of auxiliary vibrations and noise in the system.

[0053] like Figure 8 and 9 As shown in , the load cell data in the time domain is analyzed by a Fourier transform filter in the frequency domain, producing a frequency amplitude or peak ω corresponding to the variation caused by wear. Figure 8The amplitudes ω1, ω2, ω3, and ω4 are illustrated, which correspond to the weight fluctuations of the components caused by mechanical wear. Each amplitude (ω1, ω2, ω3, ω4) has a frequency F(ω4) corresponding to the degree of wear. In addition, the load cell (190, 192) can detect the vibration of the components connected in series, which corresponds to the increased frequency (as shown on the X-axis). Therefore, a single load cell can generate multiple force-frequency amplitudes (ω1, ω2, ω3, ω4) of all components connected in series using a Fourier transform filter. Each amplitude ω1, ω2, ω3, and ω4 is included in the frequency domain data 304 and compared with the threshold value stored in the memory 204.

[0054] like Fig. 9 As shown in FIG. 3 , new components, or more generally, components that do not exhibit mechanical wear, do not have detectable amplitudes in the frequency domain data 304. Therefore, by collecting time domain data 302 from the load cells (192, 194) and processing the time domain data 302 through an algorithm, frequency domain data 304 is generated that can be compared and analyzed to determine whether wear has occurred on a component.

[0055] A method 402 for detecting mechanical wear of gears or more generally components of a crucible drive unit 107 and a crystal drive unit 180 includes the steps of receiving 402 time domain data 302 from a load cell (190, 192) over a measurement time, transforming 404 the time domain data 302 into frequency domain data 304 in the frequency domain, and determining 406 whether an amplitude has exceeded a threshold amplitude. If it is determined that mechanical wear has occurred, preventive maintenance can be performed on the component before a mechanical failure occurs.

[0056] The computer systems discussed herein may include additional, fewer, or alternative functionality, including functionality discussed elsewhere herein.The computer systems discussed herein may include or be implemented via computer executable instructions stored on a non-transitory computer readable medium or media.

[0057] Unless otherwise specified, any logical flow depicted in the figure does not require the specific order or sequential order shown. In addition, other steps may be provided, or steps may be eliminated from the described process, and other components may be added to the described system or removed from the described system. The above embodiments described in detail are only examples or possible embodiments, and the scope of the present disclosure stores other combinations, additions or substitutions. In addition, the specific naming of components, the capitalization of terms, attributes, data structures or any other programming or structural aspects are not mandatory or important, and the mechanism implementing the present disclosure or its features may have different names, formats or protocols. In addition, the system may be implemented via a combination of hardware and software as described, or implemented entirely in hardware components. In addition, the functional division between the various system components described herein is only an example, not mandatory; the functions performed by a single system component may be performed by multiple components instead, and the functions performed by multiple components may be performed by a single component instead.

[0058] Approximating language, as used throughout the specification and claims, may be used to modify any quantitative representation that is permissibly variable without resulting in a change in the basic function to which it is related. Thus, values ​​modified by a term or terms, such as "about" and "substantially," are not limited to the precise values ​​specified. In at least some cases, approximating language may correspond to the precision of an instrument used to measure the value.

[0059] When introducing elements of the present disclosure or embodiments thereof, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," "containing," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. The use of terms indicating a particular orientation (e.g., "top," "bottom," "side," etc.) is for convenience of description and does not require any particular orientation of the items described.

[0060] As various changes could be made in the above constructions and methods without departing from the scope of the present disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A crystal pulling system, comprising: a crucible containing a molten semiconductor material; cables and gear; a crystal disposed at one end of the cable; a motor for pulling the cable and crystal out of the melt; a load cell connected to the gear to measure the force applied to the gear; and, A control system comprising a processor connected to the load cell, the processor configured to process data received from the load cell, the processor configured to: receiving time domain data from the load cell during a measurement time during a crystal pulling process, transforming the time domain data into frequency domain data in the frequency domain, the frequency domain data comprising the force-frequency amplitude within the measurement time; and, A determination is made as to whether the force-frequency amplitude has exceeded a threshold.

2. The system of claim 1, wherein the load cell reads a predetermined number of data samples within the measurement time.

3. The system of claim 1, wherein the processor is configured to identify an operating condition in which the processor receives time domain data from the load cell.

4. The system of claim 3, wherein the operating conditions include pulling the crystal to one of 100% of the total crystal length, 80% of the total crystal length, 60% of the total crystal length, and 20% of the total crystal length.

5. The system of claim 1, wherein the processor applies an algorithm to transform the time domain data into frequency domain data.

6. The system of claim 1, wherein the processor applies one of a Fourier transform, a fast Fourier transform, and a discrete Fourier transform to transform the time domain data into frequency domain data.

7. The system of claim 1, wherein the load cell measures at least one of a force on the gear, a vibration of the gear during rotation of the gear, and a vibration of a gear of the motor.

8. The system of claim 1, wherein the load cell is in situ with the gear and the motor.

9. The system of claim 8, wherein the load cell is suspended from the gear by a tensioned anchor.

10. The system of claim 9, wherein the load cell measures vibrations of a gear connected in series to the motor.

11. The system of claim 10, wherein the processor is further configured to: The time domain data is transformed into frequency domain data, the frequency domain data comprising a plurality of force-frequency amplitudes; and, determining whether one or more of the plurality of amplitudes has exceeded a threshold amplitude.

12. The system of claim 11, wherein each of the plurality of amplitudes corresponds to a vibration of the gear.

13. A detection system for detecting mechanical wear of a gear in a crystal puller, comprising: a load cell connected to the gear to measure the force applied to the gear in the time domain; and, A control system comprising a processor connected to the load cell, the processor configured to process data received from the load cell, the processor configured to: receiving time domain data from the load cell during a measurement time during a crystal pulling process, instructing the processor to transform the time domain data into frequency domain data in the frequency domain, the frequency domain data comprising amplitudes within the measurement time; and, The processor is instructed to determine whether the amplitude has exceeded a threshold amplitude.

14. The system of claim 13, wherein the gear is connected in series to a gear of a motor of a pulling mechanism, the pulling mechanism comprising a drum with a winding cable to pull the crystal from the molten semiconductor material.

15. The system of claim 14, wherein the gears are connected in series via an axle, shaft, or worm gear.

16. The system of claim 13, wherein the gear is connected to a motor of a crucible assembly, the crucible assembly including a shaft that rotates the crucible during a crystal pulling process.

17. The system of claim 13, wherein the load cell measures vibration of the gear during rotation of the gear.

18. A method for detecting mechanical wear of a gear in a crystal puller, comprising the steps of: receiving time domain data from a load cell during a measurement time, the load cell being coupled to the gear to measure a force applied to the gear in the time domain; transforming the time domain data into frequency domain data in the frequency domain, the frequency domain data comprising the amplitude within the measurement time; and, A determination is made as to whether the amplitude has exceeded a threshold amplitude.

19. The method of claim 18, wherein the processor applies a Fourier transform to transform the time domain data into frequency domain data in the frequency domain.

20. The method of claim 18, wherein the amplitude of the worn gear is greater than the amplitude of the intact gear.

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