Method and device for producing a crystal rod with reduced pendular deflection during the pulling process

Abstract

The invention relates to a method of producing a single-crystal rod, in particular of silicon, by means of a pulling device (110) of a crystal-pulling device (100), wherein the crystal-pulling device (100) defines a point of pendular rotation D through which a defined axis of pendular rest for the crystal runs substantially along a vertical axis , wherein, during at least one pulling process, the actuation of the pulling de vice (110) by a control device (120) is used to pull a substantially successively progressing single-crystal-rod section with an accompanying substantially successively progressing associated single-crystal length from a melt according to a settable, variable target pulling rate of the pulling device (110) to produce the single-crystal rod. During at least one phase of the pulling process, such a specifically selected, variable setting of the target pulling rate is undertaken by way of a specifically selected actuation of the pulling device (110) by the control device (120) that, after each change in the setting of the target pulling rate has been made for the continuation of the pulling process, maximum pendular deflections of the progressing single-crystal-rod section, based on the axis of pendular rest for the crystal, are obtained as a function of the progressing pulling time and / or progressing single-crystal length, of which the magnitudes and / or differential magnitudes from successive magnitudes are reduced at least in phases.

Description

[0001] Method and device for producing a crystal rod with reduced pendulum deflection during the pulling process

[0002] Technical area

[0003] The invention relates to a method for producing a single-crystal rod with reduced pendulum deflection, as well as the subsequent production of wafers made of semiconductor material. The invention further relates to a crystal pulling device and the use of the crystal pulling device for reducing pendulum deflections. Finally, the invention relates to a computer program for reducing pendulum deflections, as well as to a computer-readable medium on which this computer program is stored.

[0004] State of the art and technical task

[0005] Primarily in crystal pulling devices which are operated with a pulling device in the form of a rope pendulum device, it is known that pendulum movements of the mass unit hanging on the pulling rope occur during the actual crystal pulling process (i.e. in particular the growing crystal rod), but also during process steps upstream or downstream of the actual crystal pulling process on the mass unit hanging on the pulling rope (i.e. concerning the movement of the melt cover or other components of the crystal pulling device which, for example, have to be lifted). In this case, it can happen that a maximum pendulum deflection of the mass unit, related to a crystal pendulum rest axis, assumes such large values ​​that the mass unit collides, for example, with the edge of the crucible of the crystal pulling device and corresponding damage to the crucible and in particular to the hanging mass unit, i.e.for example, on the crystal rod in the manufacturing process or on components of the crystal pulling device.

[0006] However, with regard to the actual crystal pulling process, damage to the growing crystal rod occurs long before the growing crystal rod collides with the crucible rim: even a slight pendulum deflection results in yield losses, as the crystal no longer grows cylindrically or is pulled from the melt. Such crystal growth is inherently detrimental and renders the produced crystal rod (section) unusable.

[0007] In order to enable crystal pulling even within the resonance frequency of the system, an active counter-control of the pendulum movement is required.

[0008] To solve this problem, an active control system for the crystal pulling device using an "XY table" below the cable rotating head is known from the prior art, as described, for example, in DE 102009024472 A1. To reduce pendulum deflections during the pulling process, the cable rotating head is displaced transversely (along the X and Y directions) relative to the vertical axis via the XY table. However, providing such a movable XY table below the cable rotating head to counteract pendulum deflections during the pulling process requires a complex structural and control design.

[0009] The present invention is therefore based on the objective, technical problem of providing in a simple manner, in particular, a method and a device for producing a single-crystal rod with reduced pendulum deflection, which does not have the above-mentioned disadvantages or at least to a lesser extent and which, in particular, does not require the provision of a displaceable XY table below a cable rotating head to counteract or reduce pendulum deflections.

[0010] According to a first aspect, the object is achieved by a method for producing a single-crystal rod according to the features of claim 1, according to a second aspect by a crystal pulling device according to the features of claim 9, according to a third aspect by its use for reducing pendulum deflections according to claim 11, and finally according to a fourth aspect by a computer program for reducing pendulum deflections according to the features of claim 12. Furthermore, the invention relates to a computer-readable medium according to claim 13 on which this computer program is stored. Finally, the invention relates to the further processing of wafers made of semiconductor material according to claim 14, based on the method according to the invention or its preferred variants for producing a single-crystal rod with reduced pendulum deflection.

[0011] The invention is based on the technical teaching that a crystal rod can be produced in a simple manner and in particular without the additional structural structures just described, which crystal rod was pulled on the crystal pulling device with reduced pendulum deflection, by reducing, in particular damping, the maximum pendulum deflection occurring during pulling, related to a crystal pendulum rest axis, exclusively by means of a targeted, and in particular continuous and variable, adjustment of the target pulling speed. In other words, the present invention has recognized that for an effective reduction or damping of the pendulum deflection during pulling, it is sufficient to adapt the target pulling speed in response to the current result of the pendulum deflection and to do this in particular based on predeterminable switching steps and switching criteria (relating, among other things, tothe course, the change and the amount of the target pulling speed).

[0012] Description of the invention

[0013] According to a first aspect, the invention therefore relates to a method for producing a single-crystal rod, in particular made of silicon, by means of a pulling device of a crystal pulling device, wherein a pendulum pivot point D is defined by the crystal pulling device, in particular by the pulling device, through which pendulum pivot point D a defined crystal pendulum rest axis runs essentially along a height axis. During at least one pulling process, a substantially successively advancing single-crystal rod section with an associated substantially successively advancing assigned single-crystal length is pulled from a melt to form the single-crystal rod according to an adjustable, variable target pulling speed of the pulling device via the control of the pulling device with the control device.

[0014] According to the invention, it is provided that during at least one time segment of the pulling process, such a targeted, variable setting of the target pulling speed is carried out by means of a targeted control of the pulling device via a control device that, after each changed setting of the target pulling speed has been made, maximum pendulum deflections Ä of the advancing single-crystal rod section, related to the crystal pendulum rest axis, are formed for the subsequent pulling process as a function of the advancing pulling time and / or advancing single-crystal length, the amounts of which and / or the difference amounts of which from successive amounts are reduced at least in sections, in particular in comparison to amounts and / or difference amounts of maximum reference pendulum deflections ÄR,which, as an alternative to the drawing process in a reference drawing process, would form at an identical progressive drawing time and / or identical progressive single-crystal rod length on a progressive reference single-crystal rod section in which a reference single-crystal rod is drawn according to a reference process-typical reference target-target drawing speed profile.

[0015] The method according to the invention achieves in a simple manner that a reduction (or damping) of the occurring maximum pendulum deflection relative to the crystal pendulum's rest axis within the at least one time period is carried out exclusively by a targeted, and in particular continuous, adjustment of the target pulling speed. This adjustment of the target pulling speed is preferably carried out by a targeted control of the pulling device via the control device of the crystal pulling device which is already provided in generic crystal pulling devices. Thus, only the control commands for the targeted, variable adjustment of the target pulling speed change, in particular according to the switching criteria or switching steps described below, without the need to provide additional control units on the crystal pulling device or in the vicinity of the crystal pulling device.In other words, the pendulum deflection reduction according to the invention can be carried out on a conventional (generic) crystal pulling device and this by means of the execution of the computer program according to the invention (as described further below) by a computer device (comprising a processor unit) which is already provided in generic methods or crystal pulling systems.

[0016] The method according to the invention overcomes the disadvantages described at the outset in conjunction with solutions proposed in the prior art for reducing pendulum deflections.

[0017] The reference pulling process is understood to be a comparison process (carried out separately from the method according to the invention), which is therefore not carried out (simultaneously) on the crystal pulling device at the moment the method for producing the single-crystal rod is carried out. It serves as a comparison process in the sense of a Process of Reference (POR) and enables the quantification of the effect of the inventive reduction or damping of the maximum pendulum deflection. Preferably, the reference target pulling speed profile typical of the reference process follows a profile typical of conventional crystal pulling systems. The "essentially successively advancing single-crystal rod section" within the meaning of the invention, which is pulled from the melt during the pulling process, can also include temporary remelting processes. In other words, it is not absolutely necessary for the crystal rod to be in a growing state throughout.

[0018] By "at least in sections" in the sense of the invention is meant that a reduction (compared to the reference pulling process) in the amounts and / or their difference amounts from successive amounts of the pendulum deflections Ä can also only develop in sections during the advancing pulling time and / or advancing single crystal length. For example, it is possible that, by means of the method according to the invention, a significant reduction in the difference amounts from successive amounts of the pendulum deflections Ä develops at a time section at the beginning of the pulling process (in particular at the beginning of the time section of the pulling process), while towards the middle or end of the pulling process (in particular towards the middle or end of the time section of the pulling process), a significant reduction in the amounts of the pendulum deflections Ä itself (compared to the reference pulling process) develops.This influencing of the resulting deflection behavior of the single-crystal rod section can now be achieved by the targeted, variable adjustment of the target pulling speed (via the corresponding control of the pulling device via the control device). Thanks to the flexible design options of the targeted adjustment of the target pulling speed, particularly as a function of a predefined pendulum deflection trigger threshold, a multitude of further curve variations are possible.

[0019] The method according to the invention is suitable for implementation on a crystal pulling device with a pulling device in the form of a cable pendulum device, as well as for implementation on a crystal pulling device with a pulling device in the form of a conventional CZ pulling device with a rod assembly. However, the particularly advantageous effects of the invention are particularly evident when implemented on a crystal pulling device with a pulling device in the form of a cable pendulum device.

[0020] In preferred variants, the pivot point D is defined by the pulling device and is spatially assigned to it. In embodiments of the pulling device in the manner of a rope pendulum device, the provided rope rotating head can be designed according to conventional rope rotating head designs, but without the provision of or interaction with an XY table or other (physical) unit, and can be driven in a conventional manner (via a drive unit in the form of a motor unit). In other words, no structural modification to or addition to the rope rotating head is required to carry out the method according to the invention.

[0021] In a preferred variant, the pivot point D remains essentially stationary during the drawing process or essentially performs no relative movement. However, "essentially" in this context means that, for example, if the drawing device is designed as a rope pendulum device, the position of the pivot point D can naturally vary within certain limits as a result of the winding of the rope on the drum during the drawing process, since in certain designs the unwinding point of the rope on the drum shifts during the winding of the drawing rope. This influence on the results of the pendulum deflection determination is negligible, however.

[0022] In particularly advantageous variants, it is preferably provided that the variable setting of the target pulling speed is carried out in response to the maximum pendulum deflection reaching or exceeding or falling below a predeterminable pendulum deflection triggering threshold value which is in the range from 0 mm to 100.0 mm, preferably in the range from 0.1 mm to 10.0 mm, more preferably in the range from 0.5 mm to 3.0 mm.

[0023] The control within the meaning of the invention also comprises the control and the control steps or the control device within the meaning of the invention also includes a control unit which is designed to carry out the constant comparison with the predeterminable threshold values, here in particular the at least one pendulum deflection triggering threshold value, and to set the target pulling speed in a specifically variable manner (or to maintain it at the current level until further notice) depending on the result of the comparison, in particular based on predeterminable switching criteria and predeterminable switching steps.

[0024] The pendulum trigger threshold represents a measure of the strength of the crystal pendulum movement, from which the active, targeted, variable setting of the target pulling speed is to be made; in other words, from which deflection threshold the reduction or damping is to be carried out by appropriately controlling the pulling device via the control device with a predefined target pulling speed.

[0025] In particularly advantageous variants, it is preferably provided that, during at least one time period of the pulling process, at least the course of the current, maximum pendulum deflection of the single-crystal rod section is determined as a function of the current pulling time and / or current single-crystal length by means of a pendulum motion determination device, wherein the pendulum motion determination device continuously transmits the results of the determination to a display device for further use. Additionally or alternatively, the results of the determination are transmitted to a storage device for further use. The display device and the storage device are preferably part of a computer device comprising a processor unit.

[0026] In particular, a current result is further transmitted to the control device. There, the control device can adjust the target pulling speed in a targeted manner, in particular according to at least one switching step and at least one predeterminable switching criterion (in particular as described further below), if the current maximum pendulum deflection reaches, falls below, or exceeds a predeterminable pendulum deflection trigger threshold.

[0027] In preferred variants, the pendulum motion determination device or components of the pendulum motion determination device, in particular a processing device of the pendulum motion determination device, is preferably physically assigned to a computer device (comprising a processor unit), preferably integrated therein.

[0028] In principle, the curve of the current maximum pendulum deflection of the single-crystal rod section can be determined in any way as a function of the current pulling time and / or the current single-crystal length. For example, this curve can be determined using a pendulum motion detection device, in which the respective current result of the maximum pendulum deflection is determined via a weight measurement.In particularly advantageous variants, however, it is preferably provided that a camera device of a provided pendulum movement determination device continuously records at least one image recording area comprising at least a section of a circumferential edge between the advancing single-crystal rod section and the melt as a function of time, and a processing device of the pendulum movement determination device determines the time-dependent absolute and relative position coordinates of at least the section of the circumferential edge using means of computer-based image processing (ie the relative position coordinates of the section of the currently deflected circumferential edge are determined in relation to the ideal position of the circumferential edge (iecentrally in the crystal pendulum rest axis) and on the basis of these absolute and relative spatial coordinates, at least one time-dependent and / or crystal length-dependent profile of the section of the circumferential edge of the crystal rod section is determined in the manner of pendulum oscillations of the crystal rod section with respect to the crystal pendulum rest axis and around the pendulum pivot point D, and for each pendulum oscillation n, the associated period T, zero crossing time t and the maximum pendulum deflection Ä are determined. Preferably, it is further provided that the processing device further determines at least the profile of the current, maximum pendulum deflection of the single-crystal rod section as a function of the current pulling time and / or the current single-crystal length.Preferably, the respective current result of the (maximum) pendulum deflection for the associated pendulum oscillation is determined based on the temporally assigned absolute and relative spatial coordinates of the section of the deflected orbiting edge. The result is preferably specified with respect to the crystal pendulum's rest axis in a plane perpendicular to the crystal pendulum's rest axis.

[0029] In particularly advantageous variants, it is preferably provided that at least during the period of the drawing process, the drawing device, controlled by the control device, sets the desired drawing speed depending on the current result of the maximum pendulum deflection according to at least one of the following switching steps and a predeterminable switching criterion:

[0030] I) According to a first switching criterion, a first switching step is preferably carried out as follows: as long as the currently determined result of the maximum pendulum deflection Ä remains below a predeterminable pendulum deflection triggering threshold value, a current, set target pulling speed of the pulling device, which in particular represents a first or third target pulling speed, is kept substantially constant.

[0031] In other words, this switching criterion or switching step corresponds to a state in which the active reduction or damping is not switched on as long as the currently determined result of the maximum pendulum deflection Ä is below the predeterminable pendulum deflection triggering threshold.

[0032] Additionally or alternatively:

[0033] II) According to a second switching criterion, a second switching step is preferably carried out as follows: as soon as the currently determined result of the maximum pendulum deflection Ä reaches a predeterminable pendulum deflection triggering threshold value, a switch is made essentially abruptly from a target pulling speed, which in particular represents a first or third target pulling speed, to a predeterminable target pulling speed interval, which is limited by a second upper and / or a second lower target pulling speed, wherein the second upper target pulling speed is increased by an amount A V 2o is raised with respect to the target pulling speed and the second lower target pulling speed is increased by an amount A V 2u is reduced with respect to the target pulling speed, wherein in particular the target pulling speed represents a first or third target pulling speed.

[0034] In other words, with this switching criterion or this switching step, the active reduction or damping is activated in the manner described due to the pendulum triggering threshold being reached, starting from the previously inactive state.

[0035] Additionally or alternatively:

[0036] III) According to a third switching criterion, a third switching step is preferably carried out as follows: as long as the currently determined result of the maximum pendulum deflection Ä exceeds a predeterminable pendulum deflection triggering threshold value, switching is continuously carried out essentially abruptly between a second upper target pulling speed and a second lower target pulling speed at each zero crossing time t of a pendulum movement of the crystal rod section with respect to the crystal pendulum rest axis, wherein the second upper target pulling speed is increased by an amount Av20 with respect to a target pulling speed and the second lower target pulling speed is increased by an amount Av2 U is reduced with respect to a target pulling speed, wherein in particular the target pulling speed represents a first or third target pulling speed.

[0037] In other words, this switching criterion or switching step corresponds to a state in which the active reduction or damping is switched on or activated and carries out the reduction or damping in the manner described above, as long as the currently determined result of the maximum pendulum deflection Ä exceeds the predeterminable pendulum deflection triggering threshold value,

[0038] Additionally or alternatively:

[0039] IV) According to a fourth switching criterion, a fourth switching step is carried out as follows: as soon as the currently determined result of the maximum pendulum deflection Ä falls below a predeterminable pendulum deflection triggering threshold, a. is essentially jumped from a second upper

[0040] Target pulling speed, which is increased by an amount Av20 with respect to a first or third target pulling speed, is switched to the first or third target pulling speed, and / or b. is switched essentially abruptly from a second lower target pulling speed, which is increased by an amount Av2 U with respect to a first or third target pulling speed, switching occurs to a first or third target pulling speed. In other words, with this switching criterion or this switching step, the state of active reduction or damping is switched to the inactive state (i.e., the active reduction or damping is deactivated) due to the oscillation triggering threshold being undershot.

[0041] “Substantially abrupt” also means that a ramp-like, but steep, time-delayed rise by the amount Av20 or fall by the amount Av20 is possible, as long as the dampening effect is sufficient.

[0042] It is understood that for the functioning of the switching criteria or switching steps, it is not absolutely necessary to use the exact maximum pendulum deflection or the pendulum rest axis for the determination; as long as the period T of the oscillation is in the high single-digit second range, the delay in signal processing or the system's intervention is negligible.

[0043] In particularly advantageous variants, it is preferably provided that a predeterminable pendulum deflection triggering threshold value is in the range from 0 mm to 100.0 mm, preferably in the range from 0.1 mm to 10.0 mm, more preferably in the range from 0.5 mm to 3.0 mm.

[0044] Additionally or alternatively, a predeterminable, adjustable target drawing speed, in particular according to at least one switching criterion as stated above, can be in the range from 0 mm / min to 10 mm / min, preferably in the range from 0.1 mm / min to 4 mm / min, more preferably from 0.5 mm / min to 3 mm / min.

[0045] Additionally or alternatively, a first and / or third desired drawing speed, in particular according to at least one switching criterion as stated above, can be in the range from 0 mm / min to 10 mm / min, preferably in the range from 0.1 mm / min to 4 mm / min, more preferably from 0.5 mm / min to 3 mm / min.

[0046] In particularly advantageous variants, it is preferably provided that an amount A V2o, which represents a desired drawing speed amount between a desired drawing speed, which is in particular a first or third desired drawing speed, and a second upper desired drawing speed, is adjustable in the range from 0.0001 mm / min to 3 mm / min, preferably from 0.001 mm / min to 0.1 mm / min. Preferably, the amount A V 2O is set constant over the at least one time period or is variably adjustable within the range during the at least one time period.

[0047] Additionally or alternatively, an amount A V 2u, which represents a desired drawing speed amount between a desired drawing speed, which is in particular a first or third desired drawing speed, and a second lower desired drawing speed, can be set in the range from 0.0001 mm / min to 3 mm / min, preferably from 0.001 mm / min to 0.1 mm / min. Preferably, the amount A V2u set constant over the at least one time period or variably adjustable within the range during the at least one time period.

[0048] According to a further aspect, the invention relates to a crystal pulling device for producing a single crystal rod with a pulling device, wherein the pulling device is designed to pull a substantially successively advancing single crystal rod section with an associated substantially successively advancing assigned single crystal length from a melt to the single crystal rod during at least one pulling process via the control of the pulling device with a control device according to an adjustable, variable target pulling speed of the pulling device, wherein the crystal pulling device, preferably by means of the pulling device, defines a pendulum pivot point D through which a defined crystal pendulum rest axis runs substantially along a height axis.

[0049] The crystal pulling device is designed according to the invention, in particular the control device of the crystal pulling device is designed to carry out such a targeted, variable setting of the target pulling speed during at least one time segment of the pulling process by means of a targeted control of the pulling device via the control device that, after each changed setting of the target pulling speed has been made for the subsequent pulling process, maximum pendulum deflections Ä of the advancing single-crystal rod section, related to the crystal pendulum rest axis, are formed as a function of the advancing pulling time and / or advancing single-crystal length, the amounts of which and / or the difference amounts of which from successive amounts are reduced at least in sections, in particular in comparison to amounts and / or difference amounts of maximum reference pendulum deflections ÄR,which, as an alternative to the drawing process in a reference drawing process, would be formed at an identical progressive drawing time and / or identical progressive single-crystal rod length on a progressive reference single-crystal rod section in which a reference single-crystal rod is drawn according to a reference process-typical reference target drawing speed profile.

[0050] The crystal pulling device according to the invention can be designed either with a pulling device in the form of a cable pendulum device or with a pulling device in the form of a conventional CZ pulling device with a rod assembly. However, the particularly advantageous effects of the invention are particularly evident when implemented on a crystal pulling device with a pulling device in the form of a cable pendulum device.

[0051] With the crystal pulling device according to the invention, the advantages can be achieved analogously to the inventive method described in detail above, so that reference is made to the above statements to avoid repetition. In general, the invention has been described primarily with reference to the features of the method according to the invention or its preferred variants. It is understood that these features (in conjunction with their described advantages) of the preferred variants of the method equally apply to preferred variants of the crystal pulling devices, wherein the individual device components of the crystal pulling device are then designed accordingly to carry out the associated method steps.To avoid repetition, reference is therefore made in full to the above statements and it is summarized at this point that in preferred variants of the crystal pulling device, the pulling device is preferably designed to pull a substantially successively advancing single-crystal rod section with an associated substantially successively advancing associated single-crystal length from a melt according to an adjustable, variable target pulling speed of the pulling device to the single-crystal rod according to the described method according to the invention or according to one or more of its preferred, described variants of the method during at least one pulling process via the pulling device.

[0052] According to a further aspect, the invention relates to the use of the crystal pulling device (according to the invention or according to one or more of its preferred, described variants) for reducing pendulum deflections of a mass unit suspended from a pulling device. In other words, the use of the crystal pulling device is suitable for generally carrying out a method for reducing pendulum deflections of a mass unit suspended from a pulling device (as described in the introduction, for example, melt cover).

[0053] According to a further aspect, the invention relates to a computer program comprising instructions which, when executed by a computer device (comprising a processor unit), cause the computer device, via the control device of the crystal pulling device according to the invention (or according to the variants described above), to specifically control the pulling device for producing a crystal rod with reduced pendulum deflections according to the manufacturing method according to the invention (or according to the variants described above). Furthermore, the invention relates to a computer-readable medium on which this computer program is stored.

[0054] Short description of the characters

[0055] Figure 1 shows a schematic section through a crystal pulling device 100 with a pulling device in the manner of a rope pendulum device and schematically illustrates a pendulum deflection at a circumferential edge of a current crystal rod section during the pulling process according to the invention.

[0056] Figure 2 illustrates the effect of damping the maximum pendulum deflection for a time period during the pulling process ZP1 compared to the Process of Record (POR) over the advancing single crystal rod length.

[0057] Figure 3 shows a detailed view of a section during the time period of the drawing process ZP1 (without POR comparison), in which the active damping is switched on and off according to predeterminable switching steps and switching criteria I to IV.

[0058] Preferred embodiment

[0059] The crystal pulling device 100 is designed to carry out a method for producing a single-crystal rod made of silicon and comprises a pulling device 110. The pulling device 110 is designed to pull a substantially successively advancing single-crystal rod section with an associated substantially successively advancing assigned single-crystal length from a melt according to an adjustable, variable target pulling speed of the pulling device 110 to form the single-crystal rod during a pulling process ZP1 via the control of the pulling device 110 by means of a control device 120.

[0060] The pulling device 110 of the crystal pulling device 100 is designed in the manner of a cable pendulum device. The pulling device 110 defines a pendulum pivot point D, through which a defined crystal pendulum rest axis runs essentially along a height axis H. During the pulling process, the crystal rod section oscillates around the pendulum pivot point D (or suspension point) in the manner of pendulum oscillations with respect to the crystal pendulum rest axis. Figure 1 schematically shows a current, maximum pendulum deflection (associated with a pendulum oscillation) at a current circumferential edge of a current, deflected crystal rod section during the pulling process ZP1.

[0061] The basic structure of the crystal pulling device 100 corresponds to a conventional crystal pulling device and is additionally designed with the special control device configuration for targeted control of the control device or targeted adjustment of the target pulling speed for operation with reduced pendulum deflection. Therefore, conventional components of a crystal pulling device will not be discussed in detail.

[0062] The control device 120 is designed to carry out such a targeted, variable setting of the target drawing speed v during a time period of the drawing process ZP1 sby means of a targeted control of the pulling device 110, in such a way that, after each change in the setting of the target pulling speed for the subsequent pulling process, maximum pendulum deflections Ä of the advancing single-crystal rod section, related to the crystal pendulum rest axis, are formed as a function of the advancing pulling time and advancing single-crystal length, the amounts of which are reduced compared to amounts which, as an alternative to the pulling process in a reference pulling process (Process of Record, POR), see Figure 2, would be formed in each case with an identical advancing pulling time and identical advancing single-crystal rod length on an advancing reference single-crystal rod section in which a reference single-crystal rod is pulled according to a reference target pulling speed profile typical of the reference process.Specifically, the reduction (in the sense of damping) of the maximum pendulum deflection relative to the crystal pendulum's rest axis within the time period is achieved exclusively through the targeted (continuous) adjustment of the target pulling speed. This damping effect, compared to the POR, is shown in Figure 2 for a time period during the pulling process ZP1 over the advancing single-crystal rod length.

[0063] Determination of the course of the current pendulum deflection during the drawing process ZP1:

[0064] A pendulum motion detection device 130 is provided to determine the course of the current pendulum deflection. A camera device 131 of the pendulum motion detection device 130 continuously records at least one image recording area comprising at least a portion of a peripheral edge UK between the advancing single-crystal rod section and the melt as a function of time. A portion of the peripheral edge UK is indicated as a point in the schematic sectional view in Figure 1.Furthermore, a processing device 132 of the pendulum motion determination device 130 is provided, which determines the time-dependent spatial coordinates of at least the section of the circumferential edge using computer-based image processing and, on the basis of these spatial coordinates, determines a time-dependent and crystal-length-dependent profile (of the section) of the circumferential edge of the crystal rod section in the manner of pendulum oscillations of the crystal rod section with respect to the crystal pendulum's rest axis and around the pendulum pivot point D, and determines for each pendulum oscillation n, the associated period T, zero-crossing time t, and the maximum pendulum deflection Ä. Finally, the processing device 132 determines the profile of the current, maximum pendulum deflection of the single-crystal rod section as a function of the current pulling time and the current single-crystal length.

[0065] The pendulum movement determination device 130 continuously transmits the results of the determination for further use to a display device 210. In addition, the results of the determination are transmitted to a storage device 220 for further use. The display device and the storage device are part of a computer device 200 comprising a processor unit 201. A current result is additionally transmitted to the control device 120 and, if the currently determined result of the maximum pendulum deflection reaches or exceeds or falls below a predeterminable pendulum deflection triggering threshold value PAS, the control device 120 sets the target pulling speed v s specifically according to at least one switching step or a predeterminable switching criterion, as described below. Description of the targeted setting of the target pulling speed v s during the

[0066] ZP1 :

[0067] With reference to Figure 2 and in particular Figure 3, a continuous, variable adjustment of the target pulling speed vs is now carried out for the single crystal rod to be produced on the crystal pulling device 100 in response to the current result of the maximum pendulum deflection reaching or exceeding or falling below a predeterminable pendulum deflection triggering threshold value PAS, which in the present embodiment has a value of 1.5 mm.

[0068] Figure 3 shows a detailed view of a section during the drawing process ZP1 period, in which the active damping is switched on and off according to predeterminable switching steps and switching criteria I to IV, which will now be described: Depending on the current value of the determined maximum pendulum deflection in comparison to the pendulum deflection triggering threshold value PAS, the setting of the target drawing speed follows one of the following switching steps during the drawing process ZP1 period or the setting is made according to a predeterminable switching criterion (by controlling the drawing device 110 accordingly via the control device 120):

[0069] I) According to a first switching criterion, a first switching step is carried out as follows: as long as the currently determined result of the maximum pendulum deflection Ä remains below the pendulum deflection triggering threshold PAS, a current, set first target pulling speed of the pulling device 110 is kept substantially constant.

[0070] II) According to a second switching criterion, a second switching step is carried out as follows: as soon as the currently determined result of the maximum pendulum deflection Ä reaches the pendulum deflection triggering threshold PAS, the system switches essentially abruptly from the first target pulling speed to a predeterminable target pulling speed interval, which is limited by a second upper and a second lower target pulling speed, wherein the second upper target pulling speed is increased by an amount A V2o is raised with respect to the first target pulling speed and the second lower target pulling speed is increased by an amount A V 2u is reduced with respect to the first target pulling speed. III) According to a third switching criterion, a third switching step is carried out as follows: as long as the currently determined result of the maximum pendulum deflection Ä exceeds the pendulum deflection triggering threshold PAS, switching is continuously carried out essentially abruptly between the second upper target pulling speed and the second lower target pulling speed at each zero crossing time t of a pendulum movement of the crystal rod section with respect to the crystal pendulum rest axis, wherein the second upper target pulling speed is again reduced by an amount A V 2o is raised with respect to the first target pulling speed and the second lower target pulling speed is increased by an amount A V2u is reduced with respect to the first target pulling speed.

[0071] IV) According to a fourth switching criterion, a fourth switching step is carried out as follows: as soon as the currently determined result of the maximum pendulum deflection Ä falls below the pendulum deflection triggering threshold PAS, the system switches essentially abruptly from the second upper target pulling speed or from the second lower target pulling speed (depending on the current state before switching) to the first target pulling speed.

[0072] The effect of the "active" damping of the pendulum deflection according to the switching criteria compared to the POR is shown in Figure 2. The curves are shown as a function of the advancing single crystal length. In the present embodiment, the first target pulling speed is 0.525 mm / min and the value A V 2o and the amount A V2u, at a size of 0.04 mm / min. Figures 2 and 3 also show the curve of the current actual drawing speed Vj [mm / min], which is set in the system in response to the specified target drawing speed. Figure 3 shows a detailed section of the curve from Figure 2, which includes all four steps or switching criteria I to IV.

[0073] The crystal rod produced under reduced pendulum deflection is then removed from the crystal pulling device 100 and subjected to a further process for producing a wafer of semiconductor material, which comprises the following steps:

[0074] Sawing the single crystal rod into thin slices, • Chemical and mechanical further treatment of the thin slices of semi-material, whereby the further treatment includes the further treatment steps of edge rounding, lapping, cleaning and polishing.

[0075] The described method is generally suitable for reducing pendulum deflections of a mass unit hanging on a pulling device.

[0076] Furthermore, the exemplary embodiment provides a computer program comprising instructions that, when executed by a computer device 200 (comprising a processor), cause the computer device 200 to specifically control the crystal pulling device 110 via the control device 120 of the crystal pulling device 100 for the production of the crystal rod with reduced pendulum deflections according to the described production method. This computer program is stored on a computer-readable medium 300.

Claims

Claims 1. A method for producing a single crystal rod, in particular made of silicon, by means of a pulling device (110) of a crystal pulling device (100), wherein a pendulum pivot point D is defined by the crystal pulling device (100), through which pivot point D a defined crystal pendulum rest axis runs essentially along a height axis, wherein during at least one pulling process, via the control of the pulling device (110) with a control device (120), a substantially successively advancing single crystal rod section with an associated substantially successively advancing assigned single crystal length is pulled from a melt according to an adjustable, variable target pulling speed of the pulling device (110) to the single crystal rod, wherein during at least one time period of the pulling process, such a targeted,variable setting of the target pulling speed is carried out via a targeted control of the pulling device (110) via the control device (120), so that after each changed setting of the target pulling speed for the subsequent pulling process, maximum pendulum deflections of the advancing single-crystal rod section, related to the crystal pendulum rest axis, are formed as a function of the advancing pulling time and / or advancing single-crystal length, the amounts of which and / or the difference amounts of which from successive amounts are reduced at least in sections, in particular in comparison to amounts and / or difference amounts of maximum reference pendulum deflections which would form alternatively to the pulling process in a reference pulling process in each case with an identical advancing pulling time and / or identical advancing single-crystal rod length on an advancing reference single-crystal rod section,in which a reference single crystal rod is pulled according to a reference process-typical reference target pulling speed profile.

2. Method according to claim 1, wherein the reduction, in particular damping, of the occurring maximum pendulum deflection related to the crystal pendulum rest axis within the at least a period of time is carried out exclusively via the targeted, and in particular continuous, setting of the target pulling speed, and / or the variable setting of the target pulling speed is carried out in response to the current result of the maximum pendulum deflection reaching or exceeding or falling below a predeterminable pendulum deflection triggering threshold value which lies in the range 0 mm to 100.0 mm, preferably in the range from 0.1 mm to 10.0 mm, more preferably in the range from 0.5 mm to 3.0 mm.

3. Method according to claim 1 or 2, wherein a camera device (131) of a pendulum motion determination device (130) continuously records at least one image recording area comprising at least a section of a circumferential edge between the advancing single-crystal rod section and the melt as a function of time, and a processing device (132) of the pendulum motion determination device (130) determines the time-dependent spatial coordinates of at least the section of the circumferential edge using computer-based image processing and, on the basis of these spatial coordinates, determines at least one time-dependent and / or crystal length-dependent profile of the section of the circumferential edge of the crystal rod section in the manner of pendulum oscillations of the crystal rod section with respect to the crystal pendulum rest axis and around the pendulum pivot point D, and for each pendulum oscillation n, the associated period T,Zero crossing time t and the maximum pendulum deflection Ä are determined, and the processing device (132) further determines at least the course of the current maximum pendulum deflection of the single-crystal rod section as a function of the current pulling time and / or the current single-crystal length.

4. The method according to claim 3, wherein the pendulum motion determination device (130) continuously transmits the results of the determination to a display device (210) for further use and / or the results of the determination are transmitted to a storage device (220) for further use, wherein the display device (210) and the storage device (220) are part of a computer device (200) comprising a processor unit (201), and the current result of the determination of the maximum pendulum deflection is transmitted to the control device (120) and if the current result of the maximum pendulum deflection reaches, falls below or exceeds a predeterminable pendulum deflection triggering threshold value, the control device (120) adjusts the target pulling speed in a targeted manner, in particular according to at least one switching step and following at least one predeterminable switching criterion.

5. Method according to one of the preceding claims, wherein at least during the time period of the drawing process, the drawing device (110), controlled via the control device (120), sets the desired drawing speed as a function of the current result of the maximum pendulum deflection, in particular determined according to the method and by means of the pendulum movement determination device according to claim 3 or 4, according to at least one of the following switching steps and a predefinable switching criterion: i according to a first switching criterion, a first switching step is carried out as follows: as long as the currently determined result of the maximum pendulum deflection Ä remains below a predefinable pendulum deflection triggering threshold value, a current, set desired drawing speed of the drawing device, which in particular represents a first or third desired drawing speed, is kept substantially constant.and / or ii according to a second switching criterion, a second switching step is carried out as follows: as soon as the currently determined result of the maximum pendulum deflection Ä reaches a predeterminable pendulum deflection triggering threshold value, there is a substantially abrupt switch from a target pulling speed, which in particular represents a first or third target pulling speed, to a predeterminable target pulling speed interval which is limited by a second upper and / or a second lower target pulling speed, wherein the second upper target pulling speed is increased by an amount A. V 2o is raised with respect to the target pulling speed and the second lower target pulling speed is increased by an amount A V 2u is reduced with respect to the target pulling speed, wherein in particular the target pulling speed represents a first or third target pulling speed, and / or iii according to a third switching criterion, a third switching step is carried out as follows: as long as the currently determined result of the maximum pendulum deflection Ä exceeds a predeterminable pendulum deflection triggering threshold value, switching is carried out continuously, essentially at each zero crossing time t of a pendulum movement of the crystal rod section with respect to the crystal pendulum rest axis, essentially abruptly between a second upper target pulling speed and a second lower target pulling speed, wherein the second upper target pulling speed is increased by an amount A V 2o is raised with respect to a target pulling speed and the second lower target pulling speed is increased by an amount A V2u is reduced with respect to a target pulling speed, wherein in particular the target pulling speed represents a first or third target pulling speed, and / or iv according to a fourth switching criterion, a fourth switching step is carried out as follows: as soon as the currently determined result of the maximum pendulum deflection Ä falls below a predeterminable pendulum deflection triggering threshold value, there is essentially a sudden change from a second upper target pulling speed, which is increased by an amount A V 2o is raised with respect to a first or third target pulling speed, is switched to the first or third target pulling speed, or is essentially jumped from a second lower target pulling speed, which is raised by an amount A V 2u is reduced with respect to a first or third target pulling speed, switched to a first or third target pulling speed.

6. Method according to one of the preceding claims, wherein a predeterminable pendulum deflection triggering threshold value is in the range from 0 mm to 100.0 mm, preferably in the range from 0.1 mm to 10.0 mm, more preferably in the range from 0.5 mm to 3.0 mm, and / or a predeterminable, adjustable 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 a predeterminable switching criterion, in the range from 0 mm / min to 10 mm / min.

7. Method according to one of the preceding claims, wherein an amount A V2o, which represents a target drawing speed amount between a target drawing speed, which is in particular a first or third target drawing speed, and a second upper target drawing speed, is adjustable in the range from 0.0001 mm / min to 3 mm / min, preferably from 0.001 mm / min to 0.1 mm / min, and / or an amount A V 2u, which represents a target drawing speed amount between a target drawing speed, which is in particular a first or third target drawing speed, and a second lower target drawing speed, is adjustable in the range from 0.0001 mm / min to 3 mm / min, preferably from 0.001 mm / min to 0.1 mm / min.

8. Method according to one of the preceding claims, wherein the method is carried out on a crystal pulling device (100) with a pulling device in the manner of a rope pendulum device, or the method is carried out on a crystal pulling device (100) with a pulling device in the manner of a conventional CZ pulling device with a rod unit.

9. A crystal pulling device for producing a single crystal rod, comprising a pulling device (110), wherein the pulling device (110) is configured to pull, during at least one pulling process, a substantially successively advancing single crystal rod section with an associated substantially successively advancing associated single crystal length from a melt to the single crystal rod according to an adjustable, variable target pulling speed of the pulling device, via the actuation of the pulling device (110) with a control device (120), wherein the crystal pulling device, preferably by means of the pulling device (110), defines a pendulum pivot point D, through which a defined crystal pendulum rest axis extends substantially along a height axis, characterized in that the crystal pulling device (100), in particular the control device (120) of the crystal pulling device (100), is designed to carry out a targeted, variable setting of the target pulling speed during at least one time segment of the pulling process by means of a targeted control of the pulling device via the control device (120) such that, after a changed setting of the target pulling speed has been made, maximum pendulum deflections of the advancing single-crystal rod section, related to the crystal pendulum rest axis, are formed for the subsequent pulling process as a function of the advancing pulling time and / or advancing single-crystal length, the amounts and / or the differences between successive amounts of which are at least partially reduced, in particular in comparison to amounts and / or differences of maximum reference pendulum deflections,which, as an alternative to the drawing process in a reference drawing process, would be formed at an identical progressive drawing time and / or identical progressive single-crystal rod length on a progressive reference single-crystal rod section in which a reference single-crystal rod is drawn according to a reference process-typical reference target drawing speed profile.

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

11. Use of the crystal pulling device according to claim 9 for reducing pendulum deflections of a mass unit suspended from a pulling device (110).

12. A computer program comprising instructions which, when the program is executed by a computer device (200) comprising a processor unit (201), cause the latter to specifically control, via the control device (120) of the crystal pulling device (100) according to claim 9 or 10, its pulling device (110) for the production of a crystal rod with reduced pendulum deflections according to the production method according to one of claims 1 to 8.

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

14. A method for producing a wafer of semiconductor material from a single-crystal rod which has been produced with reduced pendulum deflection according to a method for producing a single-crystal rod according to one of claims 1 to 8, wherein, starting from the end of the method for producing the single-crystal rod, at least the following steps follow: • Sawing the single crystal rod into thin slices, • Chemical and / or mechanical further treatment of at least one of the thin slices of semi-material, wherein the further treatment comprises at least one further treatment step of edge rounding, lapping, cleaning, polishing, Deposition of an oxide layer, epitaxial growth of a single-crystalline layer, in particular a silicon layer, or a SiGe layer or a GaN layer.

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