Method and apparatus for producing a crystal bar with reduced wobble during a pulling process

Abstract

The present invention relates to a method for producing single crystal rods, particularly silicon single crystal rods, by means of a pulling device (110) of a crystal pulling apparatus (100), wherein the crystal pulling apparatus (100) defines a pendulum rotation center D, the defined stationary axis of the crystal pendulum extends substantially along and through the height axis, wherein, during at least one pulling process, a substantially progressive single crystal rod segment having an associated substantially progressive specified single crystal length is pulled from the melt according to a configurable variable target pulling speed of the pulling device (110) via a control device (120) to obtain a single crystal rod. During at least one stage of the pulling process, the target pulling speed is controlled and variablely set via controlled actuation of the pulling device (110) and the control device (120), such that after each change in the setting of the target pulling speed, in order to continue the pulling process, the maximum pendulum deflection of the asymptotic single crystal rod segment based on the stationary axis of the crystal pendulum develops into a function of the asymptotic pulling time and / or the asymptotic single crystal length, the amplitude of which and / or the difference in amplitude relative to the continuous amplitude decreases at least during the stage.

Description

Technical Field

[0001] This invention relates to a method for producing a single crystal rod with reduced pendulum deflection, and to producing a wafer by further processing a semiconductor material. The invention also relates to a crystal pulling apparatus and its use for reducing pendulum deflection. Finally, the invention relates to a computer program for reducing pendulum deflection, and a computer-readable medium storing this computer program thereon. Background Technology

[0002] In crystal pulling apparatuses primarily operated with cable pendulum-type pulling devices, it is known that the pendulum motion of the mass unit suspended on the pulling cable occurs during the actual pulling process (i.e., particularly the growing crystal rod), but also during process steps involving the mass unit suspended on the pulling cable before or after the actual pulling process (i.e., especially those related to the movement of the melt cover or other components of the crystal pulling apparatus, such as those that must be lifted). It is possible that the maximum pendulum deflection of the mass unit based on the stationary axis of the crystal pendulum has a large amplitude, which causes the mass unit to collide, for example, with the crucible wall of the crystal pulling apparatus, and causes corresponding damage to the crucible, particularly to the suspended mass unit, i.e., to the crystal rod in the production process or to other components of the crystal pulling apparatus.

[0003] However, in the actual pulling process, damage to the growing crystal rod occurs long before it collides with the edge of the crucible: even with slight pendulum deflection, there is a loss of yield because the crystal no longer grows in a cylindrical manner or is pulled out of the melt. Such crystal growth is naturally disadvantageous and renders the resulting crystal rod (segment) unusable.

[0004] In order to achieve crystal pulling even within the system's resonant frequency, active control is required to counteract the pendulum motion.

[0005] A known solution to this problem from the prior art is to implement active closed-loop control of the crystal pulling device by means of an "XY stage" below the cable's rotating head, as described, for example, in DE 102009024472 A1. In this case, the sway deflection during the pulling process is reduced by moving the cable's rotating head through the XY stage in the lateral directions (along the X and Y directions) relative to the height axis. However, providing such a movable XY stage below the cable's rotating head to counteract the sway deflection during the pulling process requires complex setup in terms of construction and control technology.

[0006] Therefore, the present invention is based on the objective technical problem of providing a method and apparatus, particularly for producing single crystal rods with reduced pendulum deflection, in a simple manner, which has the aforementioned disadvantages, at least to the extent of reduction, and in particular does not require providing a movable XY stage below the rotating head of the cable to counteract or reduce the pendulum deflection.

[0007] In a first aspect, this objective is achieved by a method for producing single crystal rods according to the features of claim 1; in a second aspect, by a crystal pulling apparatus according to the features of claim 9; in a third aspect, by reducing pendulum deflection using a crystal pulling apparatus according to claim 11; and finally, in a fourth aspect, by a computer program for reducing pendulum deflection according to the features of claim 12. The invention also relates to a computer-readable medium according to claim 13, on which the computer program is stored. Finally, the invention relates to the production of wafers from semiconductor materials by further processing according to claim 14 using the method of the invention or a preferred variation thereof for producing single crystal rods with reduced pendulum deflection.

[0008] This invention is based on the teachings of this technology, namely, that a crystal bar already pulled on a crystal pulling apparatus with a reduced pendulum deflection can be manufactured in a simple manner and, in particular, without the additional structural configuration just described, because the reduction, especially attenuation, of the maximum pendulum deflection based on the stationary axis of the crystal pendulum during pulling is achieved solely through controlled, and particularly continuous and variable, settings for the target pulling speed. In other words, the invention has determined that it is sufficient to effectively reduce or attenuate the pendulum deflection during pulling to match the target pulling speed in response to the current result of the pendulum deflection, and in particular to pull with reference to definable switching steps and following switching criteria (particularly relating to the progress, variation, and magnitude of the target pulling speed). Summary of the Invention

[0009] Therefore, in a first aspect, the present invention relates to a method for producing single crystal rods, particularly silicon single crystal rods, by means of a pulling device of a crystal pulling apparatus, wherein the crystal pulling apparatus, particularly the pulling device, defines a pendulum rotation center D through which the defined stationary axis of the crystal pendulum extends substantially along the height axis. During at least one pulling process, a substantially progressively increasing segment of a single crystal rod having an associated substantially progressively increasing specified single crystal length is pulled from the melt by means of an actuation of the pulling device with a control device, according to a configurable variable target pulling speed of the pulling device, to obtain a single crystal rod.

[0010] According to the invention, it is envisioned that during at least one stage of the pulling process, this controlled, variable setting of the target pulling speed is performed via controlled actuation of the pulling device through a control device, such that after each change in the setting of the target pulling speed, in order to continue the pulling process, the maximum pendulum deflection  of the asymptotic single crystal rod segment based on the stationary axis of the crystal pendulum develops into a function of the asymptotic pulling time and / or the asymptotic single crystal length, the magnitude of which and / or the magnitude of the difference between the amplitudes relative to the continuous amplitudes decreases at least within the stage, particularly by replacing the maximum reference pendulum deflection  generated in the pulling process during the reference pulling process. R The amplitude and / or difference amplitude are compared, in each case having the same progressive pull time and the same progressive single crystal rod length on the progressive reference single crystal rod segment, wherein the reference single crystal rod is pulled according to the reference process - a typical reference target pull speed profile.

[0011] The method of the present invention achieves, in a simple manner, a reduction (or attenuation) of the maximum pendulum deflection based on the stationary axis of the crystal pendulum, which occurs only in at least one stage via a controlled and, in particular, continuous setting of the target pulling speed. This setting of the target pulling speed is preferably performed via controlled actuation of the pulling device via a control device of the crystal pulling device, which is in any case provided in a general crystal pulling device. Thus, all these changes are actuation commands for a controlled, variable setting of the target pulling speed, particularly according to switching criteria or switching steps further described below, without the need to provide additional units for actuation on or in the environment of the crystal pulling device. In other words, the reduction of pendulum deflection according to the invention can be performed on a conventional (general) crystal pulling device, and by means of the execution of the computer program of the invention (as further described below), by means of a computer device (including a processor unit) provided in any case in a general method and crystal pulling system.

[0012] The method of the present invention overcomes the shortcomings described at the outset of the methods for reducing pendulum deflection referenced in the prior art.

[0013] The reference pull process refers to a comparison process performed separately from the method of this invention; that is, a process that does not occur (simultaneously) on the crystal pulling apparatus when performing the method for producing single crystal rods. It acts as a comparison process in the sense of a reference process (POR) and can quantify the effect of a reduction or attenuation in the maximum pendulum deflection of this invention. The reference process—a typical reference target pull speed curve—preferably follows the typical process progression of a conventional crystal pulling system.

[0014] In the context of this invention, the “substantially progressive single crystal rod segment” pulled from the melt during the pulling process may also include a temporary remelting process. In other words, the crystal rod does not absolutely have to be in a constant growth state.

[0015] In the context of this invention, "at least in the segment" means that the reduction in the magnitude of the pendulum deflection  and / or the magnitude of its difference relative to the continuous magnitude (by comparison with a reference pulling process) may, in various cases, develop only in the segment during the progressive pulling time and / or progressive single crystal length. For example, it is possible, by means of the method of this invention, to produce a high reduction in the magnitude of the difference between the pendulum deflection  and the continuous magnitude at the beginning stage of the pulling process (especially at the beginning of a stage of the pulling process), and in contrast, to establish a high reduction in the magnitude of the pendulum deflection  itself (compared to a reference pulling process) toward the middle or end of the pulling process (especially toward the middle or end of a stage of the pulling process). This effect on the resulting deflection characteristics of the single crystal rod segment can then be achieved via a controlled, variable setting of the target pulling speed (via the pulling device via corresponding actuation of the control device). Due to the possibility of flexible configuration of the controlled setting of the target pulling speed, especially depending on a definable pendulum deflection trigger threshold, there are numerous resulting further variations.

[0016] The method of the present invention is applicable to both crystal pulling apparatuses with cable-operated pull devices and conventional CZ pull devices with frame units. However, the particularly advantageous effects of the present invention are especially evident when performed on crystal pulling apparatuses with cable-operated pull devices.

[0017] In a preferred variant, the rotation center D is defined by and spatially distributed to the pulling device. In this case, in the design of the pulling device of the cable swing device type, the provided cable rotating head can be configured according to the conventional design of the rotating cable head, but no XY stage or other (physical) unit or interacting with it is provided, and it is driven in a conventional manner (via a drive unit in the form of a motor unit). In other words, it is not necessary to change or add to the construction of the rotating cable head in order to carry out the method of the present invention.

[0018] In a preferred variation, the center of rotation D remains essentially stationary during the pulling process, or performs essentially no relative motion. However, in this respect, "essentially" means, for example, that in the case where the pulling mechanism is executed as a cable pendulum device, the center of rotation D can naturally be spatially variable within certain limitations due to the cable winding around the drum during the pulling process, since in some designs the point where the pulling cable rolls off the drum will move during the winding of the pulling cable. However, this effect on the determination of the pendulum deflection is negligible.

[0019] In a particularly advantageous variant, it is preferred that the variable setting of the target pulling speed is made in response to the maximum swing deflection reaching or exceeding or falling below a definable swing deflection trigger threshold, which is in the range of 0 mm to 100.0 mm, preferably in the range of 0.1 mm to 10.0 mm, and more preferably in the range of 0.5 mm to 3.0 mm.

[0020] In the context of this invention, actuation also encompasses closed-loop control and closed-loop control steps, and the control device in the context of this invention further includes a closed-loop control unit designed to perform a constant comparison with a limitable threshold (here, in particular, at least one swing deflection trigger threshold) and, depending on the result of the comparison, in particular with reference to a limitable switching criterion and subsequent limitable switching steps, to set the target pull speed in a controlled, variable manner (or to keep it temporarily set at the current level).

[0021] The pendulum deflection trigger threshold represents a measure of the amplitude of the crystal pendulum's motion. The target pulling speed should be actively and controllably set from this measure. In other words, the pulling device should be appropriately actuated at a limited target pulling speed via a control device from this deflection threshold to reduce or attenuate the motion.

[0022] In a particularly advantageous variant, preferably, during at least one stage of the pulling process, by means of a pendulum motion determining device, the progress of the current maximum pendulum deflection of at least the single crystal rod segment is determined as a function of the current pulling time and / or the current single crystal length, wherein, by means of the pendulum motion determining device, the determined result is continuously transmitted to an indicator device for further use. Alternatively or additionally, the determined result is transmitted to a memory device for further use. The indicator device and memory device are preferably part of a computer device including a processor unit. In particular, the current result is also transmitted to a control device. When the current maximum pendulum deflection reaches, falls below, or exceeds a definable pendulum deflection trigger threshold, the control device can variably set the target pulling speed in a controlled manner, particularly according to at least one switching step and following at least one definable switching criterion (particularly as further described below).

[0023] In a preferred variant, the pendulum motion determining device or its components, particularly the processing device of the pendulum motion determining device, is preferably physically localized to a computer device (including a processor unit) and preferably integrated therein.

[0024] In principle, the progress of the current maximum pendulum deflection of the single crystal rod segment can be determined in any desired manner as a function of the current pulling time and / or the current single crystal length. For example, this progress can be obtained by means of a pendulum motion determining device, wherein the corresponding current result of the maximum pendulum deflection is determined by a measurement of weight. However, in a particularly advantageous variant, it is preferred that the camera device of the provided pendulum motion determining device continuously records at least one imaging area as a function of time, said at least one imaging area comprising at least one segment of the circumferential edge between the traveling single crystal rod segment and the melt, and the processing device of the pendulum motion determining device, at least for the circumferential edge segment, determines its time-dependent absolute and relative position coordinates (in other words, the relative position coordinates of the currently deflected circumferential edge segment relative to the ideal position of the circumferential edge (i.e., at the midpoint of the stationary axis of the crystal pendulum) by means of computer-based image processing, and based on these absolute and relative position coordinates, the time-dependent absolute and relative position coordinates of the crystal rod segment relative to the stationary axis of the crystal pendulum are determined. Furthermore, the oscillation mode of the pendulum around the rotation center D determines at least one time-dependent and / or crystal length-dependent progression of the segment at the circumferential edge of the crystal bar segment, and, for each pendulum oscillation n, determines the specified period duration T, zero-axis intercept time t, and maximum pendulum deflection Â. Preferably, further, the processing device also determines the progression of the current maximum pendulum deflection of at least the single crystal bar segment as a function of the current pulling time and / or the current single crystal length. Preferably, the corresponding current result of the (maximum) pendulum deflection of the specified pendulum oscillation is determined starting from the timing absolute and relative position coordinates of the segment at the deflection circumferential edge. Preferably, the result is reported in a plane perpendicular to the stationary axis of the crystal pendulum.

[0025] In a particularly advantageous variant, it is preferred that, at least during a phase of the pulling process, the pulling device, actuated via a control device, sets the target pulling speed as a function of the current result of the maximum swing deflection, according to at least one of the following switching steps and following a definable switching criterion: I) According to the first switching criterion, the first switching step is preferably performed as follows: when the current determined result of the maximum swing deflection remains below the limitable swing deflection trigger threshold, the current set target pulling speed of the pulling device, especially the first or third target pulling speed, remains basically constant.

[0026] In other words, this switching criterion or this switching step corresponds to the state in which the active reduction or decay is not switched, provided that the current determined result of the maximum pendulum deflection  remains below the limitable pendulum deflection trigger threshold.

[0027] Additional or alternative: II) According to the second switching criterion, the second switching step is preferably performed as follows: once the result of the currently determined maximum swing deflection  reaches a definable swing deflection trigger threshold, there is a substantially abrupt transition from the target pulling speed, especially the first or third target pulling speed, to a definable target pulling speed interval, said interval being limited by a second upper and / or second lower target pulling speed, wherein the second upper target pulling speed increases by an amount Δ relative to the target pulling speed. v2o And the decrease in the second target pulling speed relative to the target pulling speed Δ v2u Among them, the target pulling speed, especially the first or third target pulling speed.

[0028] In other words, in the case of this switching standard or this switching step, due to the reaching of the pendulum deflection trigger threshold, the active reduction or attenuation is activated from the previous inactive state in the manner described.

[0029] Additional or alternative: III) According to the third switching criterion, the third switching step is preferably performed as follows: when the result of the currently determined maximum pendulum deflection  exceeds a definable pendulum deflection trigger threshold, there is a continuous transition between the second upper target pulling speed and the second lower target pulling speed at each zero-axis intercept time t of the pendulum motion of the crystal rod segment relative to the stationary axis of the crystal pendulum, wherein the second upper target pulling speed has increased by an amount Δ relative to the target pulling speed. v2o Furthermore, the second pull speed of the target has decreased by an amount Δ relative to the target pull speed. v2u Among them, the target pulling speed, especially the first or third target pulling speed.

[0030] In other words, this switching criterion or switching step corresponds to the state in which active reduction or attenuation is switched or activated, and the reduction or attenuation is achieved in the manner described above as long as the current determined result of the maximum pendulum deflection exceeds the definable pendulum deflection trigger threshold.

[0031] Additional or alternative: IV) According to the fourth switching criterion, the fourth switching steps are performed as follows: Once the current determination of the maximum pendulum deflection  is lower than the limitable pendulum deflection trigger threshold, a. There is an increase in pulling speed Δ relative to the first or third target. v2o The transition from the second target's pulling speed to the first or third target's pulling speed is essentially abrupt. and / or b. There is a decrease in pulling speed Δ relative to the first or third target. v2u The second target pull speed is basically a sudden change to the first or third target pull speed.

[0032] In other words, in this switching criterion or this switching step, because the value is below the swing deflection trigger threshold from the active reduction or decay state, there is a switch to the inactive state (i.e., the active reduction or decay is cut off).

[0033] "Essentially abrupt" also means that if the decay effect is sufficient, the time delay increases in a sloping but steep manner, Δ. v2o Or the decrease Δ v2u It is possible.

[0034] It will be apparent that, for the functional modes of switching standards or switching steps, it is not absolutely necessary to use the exact maximum pendulum deflection or the stationary axis of the pendulum for determination; given that the oscillation period duration T is in the high single-digit second range, the delay in signal processing or system intervention is negligible.

[0035] In a particularly advantageous variant, it is preferred that the definable pendulum deflection trigger threshold is in the range of 0 mm to 100.0 mm, preferably in the range of 0.1 mm to 10.0 mm, and even more preferably in the range of 0.5 mm to 3.0 mm.

[0036] Additionally or alternatively, particularly according to at least one switching criterion specified above, the configurable target pulling speed can be in the range of 0 mm / min to 10 mm / min, preferably in the range of 0.1 mm / min to 4 mm / min, and more preferably in the range of 0.5 mm / min to 3 mm / min.

[0037] Additionally or alternatively, the first and / or third target pulling speed (especially according to at least one switching criterion specified above) may be in the range of 0 mm / min to 10 mm / min, preferably in the range of 0.1 mm / min to 4 mm / min, and more preferably in the range of 0.5 mm / min to 3 mm / min.

[0038] In a particularly advantageous variation, the preferred case is that the amplitude Δ v2o (The amplitude of the target pulling speed, particularly between the target pulling speed of the first or third target and the second upper target, can be set in the range of 0.0001 mm / min to 3 mm / min, preferably in the range of 0.001 mm / min to 0.1 mm / min. Amplitude Δ) v2o Preferably, it is set in a constant manner during the at least one stage, or it is set in a variable manner within the range during the at least one stage.

[0039] Additionally or alternatively, the magnitude Δ v2u The amplitude of the target pulling speed, particularly between the target pulling speed of the first or third target and the second target pulling speed, can be set in the range of 0.0001 mm / min to 3 mm / min, preferably in the range of 0.001 mm / min to 0.1 mm / min. Here, the amplitude Δ... v2u Preferably, it is set in a constant manner during the at least one stage, or in a variable manner within the range during the at least one stage.

[0040] In another aspect, the present invention relates to a crystal pulling apparatus for producing single crystal rods using a pulling device, wherein the pulling device is designed, at least during the pulling process, to pull a substantially progressive single crystal rod segment having an associated substantially progressive specified single crystal length from the melt according to a configurable variable target pulling speed of the pulling device, at least during the pulling process, to obtain a single crystal rod, wherein the crystal pulling device (preferably by means of a pulling device) defines a pendulum rotation center D, the defined stationary axis of the crystal pendulum extending substantially along the height axis through the pendulum rotation center.

[0041] According to the invention, a crystal pulling apparatus, particularly a control device for the crystal pulling apparatus, is designed such that, at least during a phase of the pulling process, a controlled variable setting of a target pulling speed is achieved via controlled actuation of the pulling apparatus (via the control device). This controlled variable setting ensures that, after each change in the target pulling speed setting has been made, for the continuation of the pulling process, the maximum pendulum deflection  of the asymptotic single crystal rod segment based on the stationary axis of the crystal pendulum develops into a function of the asymptotic pulling time and / or the asymptotic single crystal length, the magnitude of which and / or the difference relative to the continuous magnitude each decreases at least within a phase, particularly by comparison with the magnitude and / or the difference of the maximum reference pendulum deflection  generated by the pulling process substitution in a reference pulling process. In each case, the same asymptotic pulling time and the same asymptotic single crystal rod length are present on the asymptotic reference single crystal rod segment, wherein the reference single crystal rod is pulled according to a reference process—typically a reference target pulling speed profile.

[0042] The crystal pulling apparatus of the present invention can be designed as a pulling device of the type with a cable swing device or as a pulling device of the type with a conventional CZ pulling device with a frame unit. However, the particularly advantageous effects of the present invention are especially evident when performed on a crystal pulling apparatus with a pulling device of the type with a cable swing device.

[0043] The crystal pulling apparatus of the present invention achieves similar advantages to the method of the present invention described in detail above, and therefore reference is made to the above observations to avoid repetition. Generally, the invention has been described primarily using features of the method according to the invention or according to preferred variations thereof. It is evident that these features of preferred variations of the method (in conjunction with the advantages described therein) are equally applicable to preferred variations of the crystal pulling apparatus, wherein individual device components of the crystal pulling apparatus are then designed accordingly to implement the associated method steps. To avoid repetition, reference is made to the full scope of the above observations, and in summary, in preferred variations of the crystal pulling apparatus, the pulling device is preferably designed to pull, via the pulling device, a substantially progressively progressive segment of a single crystal rod having an associated substantially progressively progressive specified single crystal length from the melt during at least one pulling process, according to a variable target pulling speed configurable by the pulling device, to provide a single crystal rod by one or more variations of the method of the present invention described or according to preferred embodiments thereof.

[0044] On the other hand, the present invention relates to the use of a crystal pulling apparatus (according to the invention or one or more of the variations thereof, preferably described herein) for reducing the pendulum deflection of a mass unit suspended on the pulling device. In other words, the use of the crystal pulling apparatus is adapted to the overall execution of a working method for reducing the pendulum deflection of a mass unit suspended on the pulling device (such as, as described by way of introduction, for example, melt coverage, etc.).

[0045] On the other hand, the present invention relates to a computer program comprising instructions which, when executed by a computer device including a processor unit, specifically actuates the pulling mechanism of a crystal pulling apparatus by means of a control device of the crystal pulling apparatus according to the invention, or according to the above-described variant, to produce a crystal rod having reduced pendulum deflection by means of the production method of the present invention, or according to the above-described variant. The invention also relates to a computer-readable medium on which this computer program is stored. Attached Figure Description

[0046] Figure 1 A schematic cross-section of a crystal pulling device 100 with a pulling device of the type of cable pendulum device is shown, and the pendulum deflection at the circumferential edge of the current crystal rod segment is schematically shown during the pulling process of the present invention.

[0047] Figure 2 The attenuation effect of the maximum pendulum deflection during the ZP1 phase of the pulling process is shown compared to the reference process (POR) at the asymptotic single crystal rod length.

[0048] Figure 3 A detailed view of the segment during the pull process ZP1 (without POR comparison) phase is shown, where active attenuation is switched and cut off after a definable switching step and switching criteria I to IV. Detailed Implementation

[0049] The crystal pulling apparatus 100 is designed to implement a method for producing silicon single crystal rods and includes a pulling device 110. The pulling device 110 is designed to, during the pulling process ZP1, be actuated by means of a control device 120 to pull a substantially progressive single crystal rod segment having a corresponding substantially progressive specified single crystal length from the melt according to an adjustable variable target pulling speed of the pulling device 110, so as to obtain a single crystal rod.

[0050] The pulling device 110 of the crystal pulling apparatus 100 is designed as a cable pendulum device. The pulling device 110 defines a pendulum rotation center D, and the defined stationary axis of the crystal pendulum extends substantially along and through the height axis H. During the pulling process, the crystal rod segment oscillates around the pendulum rotation center D (or suspension point) in a pendulum oscillation manner relative to the stationary axis of the crystal pendulum. Figure 1 A schematic diagram is shown of the current maximum pendulum deflection (assigned to pendulum oscillation) at the current circumferential edge of the currently deflected crystal bar segment during the pulling process ZP1.

[0051] The basic setup of the crystal pulling apparatus 100 corresponds to a conventional crystal pulling apparatus, and may be additionally configured with a specific control device for controlling the controlled actuation of the device or the controlled setting of the target pulling speed to operate with reduced swing deflection. Therefore, conventional components of the crystal pulling apparatus will not be discussed in detail.

[0052] During the pulling process ZP1 phase, the control device 120 is designed to achieve the target pulling speed v via controlled actuation of the pulling device 110. S A controlled variable setting, wherein after each change in the setting of the target pulling speed, in order to continue the pulling process, the maximum pendulum deflection  of the asymptotic single crystal rod segment based on the stationary axis of the crystal pendulum develops into a function of the asymptotic pulling time and the asymptotic single crystal length, with a reduced amplitude compared to the amplitude generated by the substitution in the reference pulling process (recorded process, POR), see [reference]. Figure 2 In each case, the same asymptotic pulling time and the same asymptotic single crystal rod length are used on the asymptotic reference single crystal rod segment, wherein the reference single crystal rod is pulled according to the reference process—typically a reference target pulling speed profile. Specifically, the reduction (in the sense of decay) of the maximum pendulum deflection of the crystal pendulum's rest axis occurring within the stage is achieved solely through a controlled (continuous) setting of the target pulling speed. Compared to POR, in Figure 2 The figure shows this decay effect relative to the length of the asymptotic single crystal rod during the time period of the pulling process ZP1.

[0053] Determine the progress of the current pendulum deflection during the pulling process ZP1. : To obtain the current progress of the pendulum deflection, a pendulum motion determining device 130 is provided. A camera device 131 of the pendulum motion determining device 130 continuously records at least one imaging region as a function of time, the imaging region comprising at least one segment of the circumferential edge UK between the traveling single crystal rod segment and the melt. A portion of the circumferential edge UK is in… Figure 1 The schematic cross-sectional view indicates the point. A processing unit 132 of the pendulum motion determining device 130 is also provided, which, at least for the circumferential edge segment, determines its time-dependent position coordinates by means of computer-based image processing, and based on these position coordinates, determines the time-dependent and crystal length-dependent progression of the circumferential edge of the crystal bar segment relative to the stationary axis of the crystal pendulum and the pendulum oscillations around the pendulum rotation center D, and for each pendulum oscillation n, determines the assigned period duration T, the zero-axis intercept time t, and the maximum pendulum deflection Â. Finally, the processing unit 132 determines the progression of the current maximum pendulum deflection of the single crystal bar segment as a function of the current pulling time and the current single crystal length.

[0054] The pendulum motion determination device 130 continuously transmits the determination results to the indicator device 210 for further use. Alternatively, the determination results can be transmitted to the memory device 220 for further use. The indicator device and memory device are part of the computer device 200, which includes the processor unit 201. The current result can be additionally transmitted to the control device 120, and when the current determination result of the maximum pendulum deflection reaches, exceeds, or falls below a defined pendulum deflection trigger threshold PAS, the control device 120 sets the target pulling speed v in a variable and controlled manner according to at least one switching step or following a defined switching criterion. S As described below.

[0055] The target pulling speed v during the pulling process ZP1 S Description of controlled settings : refer to Figure 2 And especially Figure 3 For a single crystal rod to be produced on the crystal pulling device 100, when the current result of the maximum swing deflection reaches or exceeds or falls below the definable swing deflection trigger threshold PAS, the target pulling speed v S The threshold is set continuously and variably in response, and in this working example, it has a value of 1.5 mm.

[0056] Figure 3A detailed view of the segment during the ZP1 phase of the pulling process is shown, wherein active attenuation is switched and cut off according to definable switching steps and following switching criteria I to IV, as will now be described: depending on the current magnitude of the maximum swing deflection obtained by comparison with the swing deflection trigger threshold PAS, during the ZP1 phase, the target pulling speed is set according to one of the following switching steps, or by following the definable switching criteria (by correspondingly actuating the pulling device 110 via the control device 120): I) According to the first switching criterion, the first switching step is performed as follows: while the current determination result of the maximum swing deflection  remains below the swing deflection trigger threshold PAS, the current setting of the first target pulling speed of the pulling device 110 remains basically constant.

[0057] II) According to the second switching criterion, the second switching steps are performed as follows: Once the current determined result of the maximum swing deflection  reaches the swing deflection trigger threshold PAS, there is a substantially abrupt transition from the first target pulling speed to a limitable target pulling speed interval limited by the second upper target pulling speed and the second lower target pulling speed, wherein the increase in the second upper target pulling speed relative to the first target pulling speed is Δ v2o Furthermore, the second target pulling speed decreased by Δ compared to the first target pulling speed. v2u .

[0058] III) According to the third switching criterion, the third switching step is performed as follows: When the current determination result of the maximum pendulum deflection  exceeds the pendulum deflection trigger threshold PAS, there is a continuous transition between the second upper target pulling speed and the second lower target pulling speed at approximately each zero-axis intercept time t of the pendulum motion of the crystal bar segment relative to the stationary axis of the crystal pendulum, wherein the second upper target pulling speed has increased again relative to the first target pulling speed by an amount Δ. v2o Furthermore, the second target pulling speed has decreased by an amount Δ relative to the first target pulling speed. v2u .

[0059] IV) According to the fourth switching criterion, the fourth switching step is performed as follows: once the current determination of the maximum swing deflection  is lower than the swing deflection trigger threshold PAS, there is a substantially sudden transition (depending on the current state before the switch) from the second upper target pull speed or from the second lower target pull speed to the first target pull speed.

[0060] Compared to POR, the "active" attenuation effect of the pendulum deflection based on the switching standard is... Figure 2 The progress is evident. Progress is shown as a function of the asymptotic single crystal length. In this working example, the first target pulling speed is 0.525 mm / min, and the amplitude Δ v2oand amplitude Δ v2u The speed is 0.04 mm / min. Additionally, Figure 2 and Figure 3 It also shows the current actual pulling speed v established in the system in response to a defined target pulling speed. i Progress on [mm / min]. Figure 3 It shows from Figure 2 A detailed view of the progress, which includes all four steps or switching from Standard I to IV.

[0061] Then, the crystal bar generated by the reduced pendulum deflection is removed from the crystal pulling device 100, and the process of producing a wafer from semiconductor material continues, including the following steps: • Cut the single crystal rod into thin wafers. • The thin wafers of semiconductor materials are further chemically and mechanically processed, including further processing steps such as edge rounding, grinding, cleaning and polishing.

[0062] The described method is generally suitable for reducing the pendulum deflection of a mass unit suspended on a pulling device.

[0063] In the working example, a computer program including instructions may be additionally provided, which, when executed by a computer device 200 including a processor, specifically actuates the pulling device 110 of the crystal pulling apparatus by means of a control device 120 of the crystal pulling apparatus 100 to produce a crystal rod with reduced pendulum deflection by the described production method. This computer program is stored on a computer-readable medium 300.

Claims

1. A method for producing single crystal rods, particularly silicon single crystal rods, said method by means of a pulling device (110) of a crystal pulling apparatus (100), wherein the crystal pulling apparatus (100) defines a pendulum rotation center D, and the defined stationary axis of the crystal pendulum extends substantially along the height axis through said pendulum rotation center. in, During at least one pulling process, a pulling device (110) is actuated by a control device (120), and a generally progressively increasing single crystal rod segment having an associated generally progressively increasing specified single crystal length is pulled from the melt according to an configurable, variable target pulling speed of the pulling device (110) to obtain a single crystal rod. in, During at least one stage of the pulling process, this controlled, variable setting of the target pulling speed is achieved by controlled actuation of the pulling device (110) via the control device (120) in such a way that after each change in the setting of the target pulling speed has been made, for the continuation of the pulling process, the maximum pendulum deflection of the asymptotic single crystal rod segment based on the stationary axis of the crystal pendulum develops as a function of the asymptotic pulling time and / or the asymptotic single crystal length, the magnitude of which and / or the magnitude of the difference relative to the continuous magnitude decreases at least within the stage, in particular by comparison with the magnitude of the maximum reference pendulum deflection and / or the magnitude of the difference generated by the pulling process substitution in the reference pulling process, in each case having the same asymptotic pulling time and the same asymptotic single crystal rod length on the asymptotic reference single crystal rod segment, wherein the reference single crystal rod is pulled according to the reference process - a typical reference target pulling speed curve profile.

2. The method according to claim 1, wherein The reduction, especially the attenuation, of the maximum pendulum deflection based on the stationary axis of the crystal pendulum during at least one of the aforementioned stages is achieved solely through a controlled and, in particular, continuous setting of the target pulling speed. and / or The variable setting of the target pulling speed is made in response to the current result that the maximum swing deflection reaches or is above or below a defined swing deflection trigger threshold, which is in the range of 0 mm to 100.0 mm, preferably in the range of 0.1 mm to 10.0 mm, and more preferably in the range of 0.5 mm to 3.0 mm.

3. The method according to claim 1 or 2, wherein The camera device (131) of the pendulum motion determining device (130) continuously records at least one imaging region as a function of time, said imaging region comprising at least one segment of the circumferential edge between the traveling single crystal rod segment and the melt, and The processing unit (132) of the pendulum motion determining device (130) determines, at least for the circumferential edge segment, its time-dependent position coordinates by means of computer-based image processing, and based on these position coordinates, determines at least one time-dependent and / or crystal length-dependent progression of the circumferential edge segment of the crystal rod segment by means of the pendulum oscillations of the crystal rod segment relative to the stationary axis of the crystal pendulum and around the pendulum rotation center D, and for each pendulum oscillation n, determines the assigned period duration T, the zero axis intercept time t, and the maximum pendulum deflection Â, and The processing device (132) also acquires at least the progress of the current maximum pendulum deflection of the single crystal rod segment as a function of the current pulling time and / or the current single crystal length.

4. The method according to claim 3, wherein, By means of the pendulum motion determining device (130), the determined result is continuously transmitted to the indicator device (210) for further use, and / or the determined result is transmitted to the memory device (220) for further use, wherein the indicator device (210) and the memory device (220) are part of a computer device (200) including a processor unit (201), and The current result of the maximum swing deflection is transmitted to the control device (120), and if the current result of the maximum swing deflection reaches or is higher or lower than a defined swing deflection trigger threshold, the control device (120) variably and in a controlled manner sets the target pull speed, especially according to at least one switching step and following at least one defined switching criterion.

5. The method according to any one of the preceding claims, wherein, At least during the pulling phase, the pulling device (110), actuated via the control device (120), sets the target pulling speed as a function of the current result of the maximum pendulum deflection, particularly by the method and by means of the pendulum motion determining device according to claim 3 or 4, according to at least one of the following switching steps and following a definable switching criterion: According to the first switching criterion, the first switching step is performed as follows: While the current determined result of the maximum swing deflection remains below the definable swing deflection trigger threshold, the current set target pulling speed of the pulling device, especially the first or third target pulling speed, remains essentially constant. and / or ii. According to the second switching criterion, the second switching step is performed as follows: Once the current determination result of the maximum swing deflection  reaches a limitable swing deflection trigger threshold, there is a substantially abrupt transition from the target pulling speed, especially the first or third target pulling speed, to a limitable target pulling speed interval, which is limited by the second upper target pulling speed and / or the second lower target pulling speed, wherein the increase in the second upper target pulling speed relative to the target pulling speed is Δ. v2o And the decrease in the second target pulling speed relative to the target pulling speed Δ v2u Among them, the target pulling speed, especially the pulling speed of the first or third target, and / or iii. According to the third switching criterion, the third switching step is performed as follows: When the current determination result of the maximum pendulum deflection  exceeds the definable pendulum deflection trigger threshold, there is a continuous transition between the second upper target pulling speed and the second lower target pulling speed, essentially at each zero-axis intercept time t of the pendulum motion of the crystal bar segment relative to the stationary axis of the crystal pendulum, wherein the second upper target pulling speed has increased by an amount Δ relative to the target pulling speed. v2o And the second target pulling speed has decreased by Δ relative to the target pulling speed. v2u Among them, the target pulling speed, especially the pulling speed of the first or third target, and / or iv. According to the fourth switching criterion, the fourth switching step is performed as follows: once the current determination of the maximum pendulum deflection  is lower than the limitable pendulum deflection trigger threshold, There exists an increase in pulling speed Δ relative to the first or third target. v2o The pull speed of the second target changes almost abruptly to the pull speed of the first or third target. or The decrease in pulling speed relative to the first or third target Δ v2u The second target pull speed is basically a sudden change to the first or third target pull speed.

6. The method according to any one of the preceding claims, wherein The definable pendulum deflection trigger threshold is in the range of 0 mm to 100.0 mm, preferably in the range of 0.1 mm to 10.0 mm, and more preferably in the range of 0.5 mm to 3.0 mm. and / or The configurable target pulling speed and / or first target pulling speed and / or third target pulling speed, in particular according to at least one switching step and following a configurable switching criterion, is in the range of 0 mm / min to 10 mm / min.

7. The method according to any one of the preceding claims, wherein Amplitude Δ v2o The target pulling speed range, particularly between the target pulling speed of the first or third target and the target pulling speed of the second upper target, can be set in the range of 0.0001 mm / min to 3 mm / min, preferably in the range of 0.001 mm / min to 0.1 mm / min. and / or Amplitude Δ v2u The target pulling speed range, particularly between the target pulling speed of the first or third target pulling speed and the second target pulling speed, can be set in the range of 0.0001 mm / min to 3 mm / min, preferably in the range of 0.001 mm / min to 0.1 mm / min.

8. The method according to any one of the preceding claims, wherein The method is performed on a crystal pulling device (100) having a pulling device of the type of cable swing device, or The method is performed on a crystal pulling device (100) having a conventional CZ pulling device type with frame units.

9. A crystal pulling apparatus for producing single crystal rods using a pulling device (110), wherein the pulling device (110) is designed, at least during the pulling process, to pull a substantially progressive single crystal rod segment having an associated substantially progressive specified single crystal length from the melt according to a variable target pulling speed configurable by the pulling device, via a control device (120), to obtain a single crystal rod. in, The crystal pulling apparatus, preferably by means of a pulling device (110), defines the center of rotation D of the pendulum, the defined stationary axis of the crystal pendulum extending substantially along the height axis through the center of rotation. in The crystal pulling apparatus (100), and in particular the control device (120) of the crystal pulling apparatus (100), is designed to, during at least one stage of the pulling process, perform a controlled variable setting of a target pulling speed by controlled actuation of the pulling apparatus via the control device (120), such that after each change in the setting of the target pulling speed, in order to continue the pulling process, the maximum pendulum deflection of the asymptotic single crystal rod segment based on the stationary axis of the crystal pendulum develops as a function of the asymptotic pulling time and / or the asymptotic single crystal length, the magnitude of which and / or the magnitude of the difference relative to the continuous magnitude decreases at least within the stage, particularly by comparison with the magnitude and / or the magnitude of the maximum reference pendulum deflection generated by the pulling process substitution in the reference pulling process, in each case having the same asymptotic pulling time and the same asymptotic single crystal rod length on the asymptotic reference single crystal rod segment, wherein the reference single crystal rod is pulled according to the reference process-typical reference target pulling speed curve profile.

10. The crystal pulling apparatus according to claim 9, wherein, The crystal pulling apparatus (100) performs the method according to any one of claims 1 to 8.

11. The crystal pulling apparatus according to claim 9 is used to reduce the pendulum deflection of the mass unit suspended in the pulling device (110).

12. A computer program comprising instructions, when executed by a computer device (200) including a processor unit (201), to specifically actuate the pulling device (110) of the crystal pulling apparatus (100) according to claim 9 or 10 by means of a control device (120) of the crystal pulling apparatus (100) to produce a crystal rod having reduced pendulum deflection by means of a production method according to any one of claims 1 to 8.

13. A computer-readable medium on which the computer program of claim 12 is stored.

14. A process for producing a wafer of semiconductor material from a single crystal rod, said single crystal rod having been produced by a method for producing a single crystal rod with reduced pendulum deflection according to any one of claims 1 to 8, wherein the process of producing the single crystal rod is terminated and then at least the following steps are performed: • The single crystal rod is sawn into thin wafers. • Subjecting at least one thin wafer of semiconductor material to further chemical and / or mechanical processing, said further processing comprising at least one of the following further processing steps: edge rounding, grinding, cleaning, polishing, epitaxial growth of an oxide layer, a single crystal layer, especially a silicon layer, or a SiGe layer, or a GaN layer.

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