Silicon single-crystal growing device and silicon single-crystal growing process that uses it

Abstract

Silicon single-crystal growth device comprising: - one chamber (10); - a crucible (30) arranged in the chamber (10) to hold a silicon melt (SM); - a heater (20) arranged outside the crucible (30) to heat the crucible (30); - a heat shielding unit (40) arranged in the chamber (10); - an auxiliary heat shielding unit (70) which is arranged above the crucible (30) in such a way that it is vertically movable; - a main control (140) for controlling a traction speed of a single crystal block (50) grown in the silicon melt (SM); - an auxiliary control (130) for controlling an increase rate of the auxiliary heat shielding unit (70); and - a pulling device (110) for pulling the single crystal block and the auxiliary heat shielding unit (70) respectively based on a control signal supplied by the main control (140) and the auxiliary control (130), wherein the auxiliary heat shielding unit (70) has a truncated cone shape with a through-opening, wherein the single crystal block (50) has a body section (B) and a shoulder section (S), and wherein the auxiliary heat shielding unit (70) is arranged above the boundary between the shoulder section (S) and the body section (B) of the single crystal block (50) at a predetermined distance (d), wherein the specified distance (d) by which the auxiliary heat shielding unit (70) is spaced upwards from a boundary of the shoulder section (S) and the body section (B) of the single crystal block (50) ranges from 150 mm to 300 mm, and wherein the rate of increase of the auxiliary heat shielding unit (70) is between 0.5 mm / min and 0.7 mm / min.

Description

Technical field

[0001] Embodiments relate to a silicon single-crystal growing device for setting a crystal defect area in a single-crystal block body section being grown, and a silicon single-crystal growing method that uses this device. Background technology

[0002] Methods for producing silicon single crystals are known, for example, from DE 195 46 987 A1, JP 2012-091 942 A, KR 10-2001-0 108 424 A, KR 10-2014-0 013 284 A, JP H06-92784 A, or JP 2007-290 961 A. Generally, zone melting (FZ) or Czochralski (CZ) processes have frequently been used to produce silicon single crystals. Growing a silicon single-crystal block using an FZ process has several problems, such as the difficulty in producing a large-diameter silicon wafer and considerably high process costs. Therefore, growing a silicon single-crystal block using the CZ process is predominant.

[0003] In the CZ process, after polycrystalline silicon has been stacked in a quartz crucible and heated by heating a graphite heating element, a crystal seed is immersed in the resulting silicon melt to cause crystallization at the interface of the silicon melt, and is then pulled while being rotated, thus completing the growth of a silicon single-crystal block.

[0004] The silicon single-crystal block grown by the above-described method comprises a neck section connected to the crystal seed and formed in a thin and elongated shape, a heel section grown by gradually increasing the diameter of the single-crystal block after a constriction process, a body section grown in an axial direction while maintaining the enlarged diameter, and an extension section formed by gradually decreasing the diameter of the single-crystal block being grown and separating it from the silicon melt.

[0005] Since, in the case of a conventional silicon single-crystal block growing device and a single-crystal block growing process that uses it, the top of the crucible is open, a single-crystal block may exhibit an uneven distribution of heat during its growing process, and furthermore, a difference in the cooling rate occurs between the central section and the circumferential section of the cross-section of the silicon single-crystal block.

[0006] Due to such a temperature gradient in the radial direction of the single-crystal block, crystal defects that form in the central and circumferential regions of the cross-section of the single-crystal block have different distributions at the same position in the axial tensile direction. Therefore, it is difficult to grow the single-crystal block while magnifying a defect-free crystal region. Revelation Technical Problem

[0007] Embodiments shall provide a silicon single-crystal growing device and a growing process in which an auxiliary heat shielding unit is arranged above the melting crucible and in which the pulling speed of the auxiliary heat shielding unit is controlled in such a way that the distribution of a defect-free area in a single-crystal block body section is increased. Technical solution

[0008] One embodiment provides a silicon single-crystal growth device comprising: a chamber, a crucible arranged in the chamber to hold a silicon melt, a heater arranged outside the crucible to heat the crucible, a heat shielding unit arranged in the chamber, an auxiliary heat shielding unit arranged above the crucible in such a way that it is vertically movable, a main controller for controlling a pull rate of a single-crystal block grown in the silicon melt, an auxiliary controller for controlling an increase rate of the auxiliary heat shielding unit, and a pull device for pulling the single-crystal block and the auxiliary heat shielding unit respectively based on a control signal supplied by the main controller and the auxiliary controller. wherein the auxiliary heat shielding unit has a truncated cone shape with a through-opening, wherein the single crystal block has a body section and a shoulder section, and wherein the auxiliary heat shielding unit is arranged above the boundary between the shoulder section and the body section of the single crystal block at a predetermined distance, wherein the predetermined distance by which the auxiliary heat shielding unit is spaced upwards from a boundary of the shoulder section and the body section of the single crystal block ranges from 150 mm to 300 mm, and wherein the rate of increase of the auxiliary heat shielding unit is between 0.5 mm / min and 0.7 mm / min.

[0009] Another embodiment provides a silicon single-crystal growth process carried out in a silicon single-crystal growth apparatus comprising: a chamber, a crucible arranged in the chamber to receive a silicon melt, a heat shielding unit arranged in the chamber, and an auxiliary heat shielding unit arranged above the crucible in such a way that it is vertically movable, wherein the process comprises: Controlling the rate of increase of the auxiliary shielding unit such that the auxiliary heat shielding unit maintains a predetermined distance from a body section of a single crystal block grown in the silicon melt, in order to increase the distribution of a defect-free area in the body section of the single crystal block. wherein the auxiliary heat shielding unit has a truncated cone shape with a through-opening, and wherein the pulling speed for the auxiliary heat shielding unit is controlled such that the auxiliary heat shielding unit is arranged above the boundary between a shoulder section and a body section of the single crystal block at a predetermined distance, wherein the predetermined distance ranges from 150 mm to 300 mm, and wherein the lifting speed of the auxiliary heat shielding unit is between 0.5 mm / min and 0.7 mm / min. Favorable results

[0010] In a silicon single-crystal growing device and a growing method according to one embodiment, an auxiliary heat shielding unit is arranged above a melting crucible and the pulling speed of the auxiliary heat shielding unit is controlled, whereby a defect area in a single-crystal block body section can be controlled and the distribution of a defect-free area can be increased. Description of the drawings Fig. Figure 1 is a view representing an embodiment of a silicon single-crystal growth device. Fig. 2a and Fig. 2b are views that represent an embodiment of an auxiliary heat shielding unit, wherein Fig. 2a shows a non-inventive embodiment and in Fig. 2b an auxiliary heat shielding unit according to the present invention is shown, Fig. Figure 3 is a view showing a section of the silicon single-crystal growth device of an embodiment, Fig. 4a and Fig. 4b are views showing the distribution of crystal defects in a body section of a single crystal block, Fig. Figure 5 is a view showing the temperature distribution in the cross-section of the single crystal block. Fig. Figure 6 is a view that shows a difference in the cooling rate in the cross-section of the single crystal block. Fig. Figure 7 is a view that represents an embodiment of a silicon single-crystal growing device, Fig. 8 is a block diagram that represents an embodiment of an auxiliary control system, Fig. 9 is a block diagram representing an embodiment of a main control system, and Fig. Figure 10 is a flowchart that represents an embodiment of a silicon single crystal growth process. Best operating mode

[0011] The following are detailed descriptions of embodiments of the present invention with reference to the accompanying drawings, in order to provide a concrete description and enhance understanding of the present invention. However, various modifications of the embodiments of the present invention are possible, and the technical spirit of the present invention should not be interpreted as being limited by the embodiments described below. The embodiments of the present invention are provided solely to provide a more complete description of the present invention to those with technical expertise.

[0012] It is understood that when reference is made to an element being formed "on" or "under" another element, it can be formed directly "on" or "under" the other element, or indirectly with intermediate elements in between. It is also understood that "on" or "under" the element can be described relative to the drawings.

[0013] In the drawings, the thickness or size of each layer may be exaggerated, omitted, or schematically represented for the sake of clarity and simplicity. Furthermore, the size of each component element does not entirely reflect its actual size.

[0014] Fig. Figure 1 is a view that represents an embodiment of a silicon single-crystal growing device.

[0015] The silicon single-crystal growth device of the in Fig. The embodiment shown in Figure 1 can comprise a chamber 10, a crucible 30 for receiving a silicon melt, a heater 20 and a heat shielding unit 40, which are arranged outside the crucible.

[0016] The chamber 10 can take the form of a cylinder with a cavity formed therein, and a (not shown) tension chamber can be connected to the chamber 10 and arranged above it.

[0017] The crucible 30 for receiving the silicon molten SM can be arranged inside the chamber 10. The crucible 30 can be located in the central region of the chamber 10, and the entire crucible can have a concave shape. Furthermore, the crucible 30 can consist of a quartz crucible that comes into direct contact with the silicon molten SM, and a graphite crucible that surrounds the outer surface of the quartz crucible and holds it in place.

[0018] The heater 20 can be arranged around the crucible 30 to supply heat towards the crucible 30. The heater 20 can be positioned at a predetermined distance from the outer circumferential surface of the crucible 30, thus placing it outside the crucible 30, and can be arranged in a cylindrical shape to surround the side section of the crucible 30. Additionally, a water cooling pipe 60 can be arranged above the chamber 10 to cool a grown single-crystal block 50.

[0019] The heat shielding unit 40 can be arranged in the chamber 10 of the single-crystal growth device to retain the heat from the crucible 30, which is heated by the heater 20. The heat shielding unit 40 can be located between the heater 20 and the chamber 10. Although the heat shielding unit 40 may comprise an upper heat shield located above the crucible 30, a lateral heat shield located around the side surface of the crucible 30, and a lower heat shield located below the crucible 30, the arrangement of the heat shielding unit 40 is not limited to these configurations.

[0020] The heat shielding unit 40 can be designed using a material and a shape that achieves optimal heat distribution in the heater 20 and the melting pot 30 and enables maximum use of heat energy without losses.

[0021] The single crystal growth device of the in Fig. According to the present invention, the embodiment shown in Figure 1 further comprises an auxiliary heat shielding unit 70.

[0022] The auxiliary heat shielding unit 70 is located above the melting pot and is vertically movable.

[0023] Fig. 2a and Fig. 2b are views that represent embodiments of an auxiliary heat shielding unit, wherein Fig. 2a shows a non-inventive embodiment and in Fig. 2b an auxiliary heat shielding unit according to the present invention is shown.

[0024] Referring to Fig. 2a and Fig. 2b An auxiliary heat shielding unit 70A or 70B may have a cylindrical side surface with open top and bottom surfaces to surround a germ clamping device and may be empty within its side surface.

[0025] The non-inventive auxiliary heat shielding unit 70A according to Fig. 2a has a disc shape; however, according to the present invention, it has, as in Fig. Figure 2b shows a truncated cone shape. The auxiliary heat shielding unit 70A or 70B can be made of graphite or carbon composite material (CCM).

[0026] The lower surface of the auxiliary heat shielding unit 70A or 70B can be flat to maintain a predetermined distance from a body section of the single crystal block.

[0027] A wire 72 can be attached to the top of the auxiliary heat shield unit 70A or 70B to adjust the vertical movement of the auxiliary heat shield unit 70A or 70B. In one embodiment of the silicon single-crystal growth device described below, the wire 72 can be a first wire 72. Although only two wires 72 are shown connected to the auxiliary heat shield unit in the drawings, the embodiment is not limited to this. Three or more wires can be connected to the auxiliary heat shield unit to adjust its movement.

[0028] Fig. Figure 3 is a view showing a section of the single crystal growth device of one embodiment.

[0029] Referring to Fig. In section 3, the auxiliary heat shielding unit 70 is arranged above the silicon melt SM being grown. In particular, the auxiliary heat shielding unit 70 is spaced upwards from the silicon single-crystal block 50, which is currently being grown from the silicon melt SM.

[0030] Furthermore, the increase rate of the auxiliary heat shielding unit 70 is controlled such that the auxiliary heat shielding unit 70 maintains a predetermined distance from a body section B of the single crystal block 50 in order to increase the distribution of a defect-free area in the body section B of the single crystal block that is currently being grown.

[0031] At this time, the specified distance between the auxiliary heat shielding unit 70 and the single crystal block body section B can be controlled in such a way that it varies accordingly based on the conditions of a growth process for the production of the single crystal block.

[0032] This means that a distance between the auxiliary heat shielding unit 70 and the single crystal block body section B can be set, for example, based on the pulling speed of the single crystal block, the temperature of the silicon melt in the crucible, or the temperature inside the chamber in the single crystal growth process.

[0033] The auxiliary heat shielding unit 70 is arranged at a predetermined distance d from the boundary of a section S and the body section B of the single crystal block 50, which is currently being grown.

[0034] In particular, the auxiliary heat shielding unit 70 is arranged above the body section B and the increase rate of the auxiliary heat shielding unit 70 is controlled such that the distance d between the auxiliary heat shielding unit 70 and the boundary of the shoulder section S and the body section B of the block, which is the starting point of the body section S, is maintained in a range of 150 mm to 300 mm.

[0035] To maintain the specified distance between the auxiliary heat shielding unit 70 and the body section B, the upward speed of the auxiliary heat shielding unit 70 ranges from 0.5 mm / min to 0.7 mm / min. If the auxiliary heat shielding unit 70 is moved upwards at a speed higher than 0.7 mm / min, the distance d between the single crystal block 50 being grown and the auxiliary heat shielding unit 70 can increase, and therefore the magnitude of the temperature gradient between the center and the periphery of the single crystal block 50 cannot be reduced by the desired value. If the auxiliary heat shielding unit 70 is moved at a speed lower than 0.5 mm / min, contact can occur between the auxiliary heat shielding unit 70 and the single crystal block 50 being grown.

[0036] The rate of increase of the auxiliary heat shielding unit 70 can be the same as the rate of growth of the single crystal block 50 that is currently being grown.

[0037] This means that while the ledge section S and the initial section of body section B are being grown in the single-crystal growth process, the acceleration rate of the auxiliary heat shielding unit 70 and the traction rate of the single-crystal block 50 can be equal in order to maintain the predetermined distance between the auxiliary heat shielding unit 70 and body section B of the single-crystal block 50. This allows the cooling rate of the body section of the single-crystal block currently being grown to be adjusted, which can increase the distribution of defect-free areas in crystals forming in the initial section of body section B.

[0038] Fig. 4a and Fig. Figure 4b shows the distribution of a crystal defect area in body section B depending on whether the auxiliary heat shielding unit 70 is applied or not.

[0039] In the drawings, the X-axis represents the axial length of the single-crystal block body section. The starting point of body section B, i.e., the boundary point of the offset section S and body section B, is 0 mm, and the length of the single-crystal block being grown increases in the axial direction.

[0040] In the drawings, the Y-axis represents the pulling velocity of the single crystal block, and the solid line indicates a change in the pulling velocity as a function of the length of the single crystal block body section.

[0041] Furthermore, the Y-axis direction can correspond to the radial direction at a position in the longitudinal direction in which the body section is grown. For example, the center of the Y-axis region in the diagram can correspond to the central section of the cross-section of the single-crystal block, and based on the center, the direction in which the Y-axis value increases and the direction in which the Y-axis value decreases can correspond to the circumferential region of the cross-section of the single-crystal block.

[0042] In the drawings, the dashed line represents the boundary of the crystal defect area. The area designated by 1) represents an octagonal defect area, which is a defect area created during hardening; the area designated by 2) represents an oxidation-induced crystal stacking fault (OiSF) area; and the area designated by 3) represents a defect-free area.

[0043] Fig. Figure 4a shows the distribution of crystal defects in the single-crystal block body section when the auxiliary heat shielding unit 70 is not applied.

[0044] Referring to the presentation of Fig. 4a it can be determined that in the case where the auxiliary heat shielding unit is not provided, a defect area contained in the single crystal block is distributed up to the position where the length of the body section is 350 mm, and it can also be determined that an area in which the same type of defects are arranged and an area in which all of an octagonal defect, an OiSF defect and a defect-free area are contained appear in the radial direction of the body section.

[0045] Compared to Fig. 4a can Fig. 4b, which represents the distribution of crystal defects in the case where the auxiliary heat shielding unit 70 is applied, it is found that a defect-free area is only distributed when the length of the body section is longer than 200 mm and the crystal defects with the same shape appear in the radial direction of the body section when the length of the body section is less than or equal to 200 mm.

[0046] This means that if the single-crystal growth process is carried out in the state in which the auxiliary heat shielding unit 70 is arranged above the silicon melt SM to maintain the predetermined distance from the single-crystal block, the auxiliary heat shielding unit 70 can prevent heat from being lost from the top of the silicon melt SM held in the crucible, thereby preventing the rapid cooling of the settling section S and the initial section of the body section B as the growth of the single-crystal block progresses, which can reduce a crystal defect area attributable to rapid cooling.

[0047] In the single-crystal growing device of the embodiment, the raising rate of the auxiliary heat shielding unit 70 can be controlled in order to reduce the temperature difference between the center and the periphery of the cross-section of the body section that is perpendicular to the raising direction of the auxiliary heat shielding unit 70.

[0048] Fig. Figure 5 is a diagram showing the temperature distribution K in the single-crystal block body section as a function of whether the auxiliary heat shielding unit 70 is applied or not. In the diagram of Fig. Figures 5 and 6, “A” and “B”, represent results for the circumferential region of the cross-section of the single-crystal block body section. “A” corresponds to the case where no auxiliary heat shielding unit is provided, and “B” corresponds to the case where the auxiliary heat shielding unit is provided. Furthermore, “C” and “D” represent values ​​for the central region of the body section's cross-section. “C” corresponds to the case where no auxiliary heat shielding unit is provided, and “D” corresponds to the case where the auxiliary heat shielding unit is provided.

[0049] Referring to Fig. 5 In the case of a single crystal block grown by a single crystal growth device that does not include the auxiliary heat shielding unit 70, a temperature difference between the center C and the circumference A of the body section is increased when the length of the body section is increased.

[0050] On the other hand, in the case of the single crystal block grown by the single crystal growing device of the embodiment, in which the auxiliary heat shielding unit 70 is included and the movement speed of the auxiliary heat shielding unit is controlled to maintain the predetermined distance between the auxiliary heat shielding unit and the body section, it can be found that there is almost no obvious temperature difference between the center D and the circumference B of the body section, even though the body section is grown until its length becomes 400 mm.

[0051] Consequently, in the single-crystal growing device of the embodiment, the auxiliary heat shielding unit 70 is provided and its rate of increase is controlled, which can reduce a temperature difference of the cross-section of the body section during the single-crystal growing process, which can lead to a uniform distribution of crystal defects.

[0052] In the single-crystal growing device of the embodiment, the raising rate of the auxiliary heat shielding unit 70 can be controlled in order to reduce the difference in the cooling rate between the center and the periphery in the cross-section of the body section that is perpendicular to the raising direction of the auxiliary heat shielding unit.

[0053] Fig. Figure 6 is a diagram showing the temperature gradient (K / cm) in the single crystal block body section as a function of whether the auxiliary heat shielding unit 70 is applied or not.

[0054] In Fig. 6. The temperature gradient can be a difference in the cooling rate. Furthermore, “A” and “C” represent the same concept as in Fig. 5 each represent the circumferential region and the center of the cross-section of the single crystal block when the auxiliary heat shielding unit is not provided, and “B” and “D” each represent the circumferential region and the center of the cross-section of the single crystal block in the case in which the single crystal growing device of the embodiment is used in which the auxiliary heat shielding unit is provided in such a way that its movement speed is controlled.

[0055] Referring to Fig. 6. It can be determined that in the case where the auxiliary heat shielding unit 70 is not applied, there is a difference in the cooling rate between the center C and the circumferential area A of the single crystal block body section, and that the difference in the cooling rate, i.e. the temperature gradient in the area where the length of the body section ranges from 100 mm to 200 mm, is greater than or equal to 5 K / cm.

[0056] In comparison to the above description, it can be stated that in the case where the single crystal growing device of the embodiment is used with the auxiliary heat shielding unit 70, there is almost no difference in the cooling rate between the center D and the circumferential area B of the body section.

[0057] Consequently, the single-crystal growth device of the embodiment can control the scaling rate of the auxiliary heat shielding unit such that the auxiliary heat shielding unit is at a predetermined distance from the single-crystal block body section, thereby reducing the difference in the cooling rate between the center and the periphery of the cross-section of the body section perpendicular to the scaling direction of the auxiliary heat shielding unit. In this way, the single-crystal growth device of the embodiment can establish a crystal defect area and increase the distribution of a defect-free area within the body section.

[0058] For example, in this embodiment, the difference in the cooling rate between the center D and the circumference B of the cross-section of the body section can be less than 1 K / cm.

[0059] Fig. Figure 7 is a view that represents an embodiment of a silicon single-crystal growing device.

[0060] With regard to the embodiment of the single crystal growing device described below with reference to the drawings, a repeated description of the embodiment of the single crystal growing device described above is omitted, and only differences are described below.

[0061] The silicon single-crystal growth device of the in Fig. In the embodiment shown in Figure 7, the chamber 10, the crucible 30 for receiving a silicon melt, the heater 20 and the heat shielding unit 40, which is arranged outside the crucible, can include a main control 140 for controlling the pulling speed of the single crystal block and an auxiliary control 130 for controlling the increasing speed of the auxiliary heat shielding unit.

[0062] Furthermore, the silicon single-crystal growing device of the embodiment can include the water cooling pipe 60, which extends from the top of the crucible 30 in the pulling direction of the single-crystal block, and a pulling device 110, which is connected to the single-crystal block and the auxiliary heat shielding unit via wires 72 and 52.

[0063] The pulling device 110 can comprise a first pulling unit 114, which is connected to the upper surface of the auxiliary heat shielding unit 70 via a first wire 72, and a second pulling unit 112, which is connected to the silicon single crystal block being grown via a second wire 52.

[0064] The first pull unit 114 can be connected to the auxiliary heat shield unit 70 to move the auxiliary heat shield unit upwards from the crucible. At least one first pull unit 114 can be provided, or several first pull units 114 can be provided to allow a balanced elevation of the auxiliary heat shield unit 70. Furthermore, several first wires 72 can be provided to connect the auxiliary heat shield unit 70 and the first pull unit 114.

[0065] The second pulling unit 112 can be used to move the single-crystal block being grown upwards from the crucible. The second pulling unit can be connected via the second wire 52 to a single-crystal seed section where the growth of the single-crystal block begins. Furthermore, the second pulling unit 112 can be connected to a seed clamping device, which is connected via the wire 52 to the upper end of the single-crystal block.

[0066] The auxiliary controller 130 can receive position information about the position of the auxiliary heat shielding unit and the grown single-crystal block body section, which is output by the traction device 110, and can also feed back a correction value calculated in the auxiliary controller 130 to the traction device 110. At this time, the feedback value can be transmitted to the second traction unit 114 of the traction device 110, which is the traction device for the auxiliary heat shielding unit.

[0067] Fig. Figure 8 is a block diagram that briefly illustrates a configuration of the auxiliary controller 130.

[0068] Referring to Fig. 8 The auxiliary control 130 can comprise a position value scanning unit 132, a distance calculator 134, a correction value generation device 136 and a first drive unit 138.

[0069] The position value scanning unit 132 can detect a position value of the body section of the grown single crystal block and a position value of the auxiliary heat shielding unit, which are tested in the pulling device.

[0070] For example, the position value of the single crystal block body section can be the value of the position at which the body section of the grown single crystal block begins, and the position value of the auxiliary heat shielding unit can be the value of the position of the lower surface of the auxiliary heat shielding unit.

[0071] The distance calculator 134 can extract a distance between the body section and the auxiliary heat shielding unit from the position values ​​of the body section and the auxiliary heat shielding unit, which are detected by the position value scanning unit 132.

[0072] In particular, the distance between the body section and the auxiliary heat shielding unit is again referred to Fig. 3 the distance d between the lower surface of the auxiliary heat shielding unit and the initial section of the body section.

[0073] The initial section of the body section corresponds to the boundary of the paragraph section S and the body section B.

[0074] The correction value generation device 136 can extract a correction value of the increase rate of the auxiliary heat shielding unit based on the distance between the body section and the auxiliary heat shielding unit, which is calculated in the distance calculator 134.

[0075] At this time, a target distance value between the body section and the auxiliary heat shielding unit can be set, and the correction value of the rate of increase can be extracted by comparing the calculated distance value with the set target distance value.

[0076] If the distance value between the body segment and the auxiliary heat shielding unit is, for example, within a target value range, the rate of increase of the auxiliary heat shielding unit, in which the correction value is reflected, can be equal to the current rate of increase. Furthermore, if the calculated distance value is greater than the target value, the corrected rate of increase can be less than the current rate of increase. Conversely, if the calculated distance value is less than the target value, the corrected rate of increase can be greater than the current rate of increase.

[0077] This means that the rate of increase of the auxiliary heat shielding unit can be adjusted so that the distance value between the body section and the auxiliary heat shielding unit coincides with the target value range.

[0078] According to the invention, the target value range extends from 150 mm to 300 mm.

[0079] The auxiliary control 130 includes the first drive unit 138.

[0080] The first drive unit 138 can output a signal that causes the auxiliary heat shielding unit to be pulled by the traction device 110. The first drive unit 138 can transmit data regarding the corrected rate of increase, generated in the correction value generation unit 136, to the traction device 110.

[0081] The first drive unit 138 can be a servo motor for operating the auxiliary heat shielding unit, during which its increase speed is controlled.

[0082] This means that the auxiliary heat shielding unit 70, which is moved upwards under the control of the auxiliary control 130, is controlled in such a way that the specified distance d to the boundary of the sorting section S and the body section B of the single crystal block 50, which is currently being grown, is maintained.

[0083] At this time, the specified distance between the auxiliary heat shielding unit 70 and the single crystal block body section B can be controlled such that it changes based on conditions of the growth process for the production of the single crystal block.

[0084] This means that the distance between the auxiliary heat shielding unit 70 and the single-crystal block body section B can be adjusted, for example, based on the pulling speed of the single-crystal block, the temperature of the silicon melt in the crucible, or the temperature inside the chamber in the single-crystal growth process.

[0085] According to the invention, the auxiliary heat shielding unit 70 is arranged above the body section B, and the speed of the auxiliary heat shielding unit 70 is controlled such that the distance d between the auxiliary heat shielding unit and the boundary of the shoulder section S and the body section B of the silicon single-crystal block, which is the starting point of the body section B, is maintained in a range of 150 mm to 300 mm.

[0086] Referring again to Fig. 7 The main control 140 can send a signal, detected by a sensor 141 located on one side above the chamber, to the pulling device 110 to adjust the pulling speed of the single crystal block.

[0087] In Fig. 7. The sensor 141 can scan the extent of the growth of the single crystal block via a viewing aperture formed in one side of the top of the chamber.

[0088] Sensor 141 can be any of the various sensors used to measure the diameter of the single-crystal block being grown, such as an infrared sensor, a CCD camera, or a pyrometer. For example, sensor 141 can be an automatic diameter control (ADC) sensor.

[0089] Information sampled by sensor 141 can be optical or image information from which a change in the diameter of the silicon single-crystal block can be estimated.

[0090] The information regarding the change in diameter in the single crystal block currently being grown, which is sampled by the sensor, can be sent to the main controller 140.

[0091] Fig. Figure 9 is a block diagram that briefly illustrates a configuration of the main controller 140.

[0092] Referring to Fig. 9 The main control unit 140 can include a diameter scanning unit 142, a train speed determination unit 144 and a second drive unit 146.

[0093] The diameter scanning unit 142 can extract a diameter value of the silicon single-crystal block from the information that is sampled and transmitted by the sensor 141 described above.

[0094] The diameter scanning unit 142 can continuously detect changes in the diameter of the silicon single crystal block depending on the process progress.

[0095] The diameter value of the silicon single-crystal block, which is detected by the diameter scanning unit 142, can be sent to the tensile speed determination unit 144.

[0096] The pull rate determination unit 144 can determine the pull rate of the single crystal block based on the diameter value of the single crystal block, which is entered by the diameter scanning unit 142.

[0097] For example, the pull rate determination unit 144 can use data regarding the diameter of the silicon single-crystal block being grown, which is input by the diameter scanning unit 142, to assess whether the pull rate of the single-crystal block should be adjusted or not, and can change the pull rate using a PID control.

[0098] This means that if, as a result of comparing the measured diameter value with the target diameter value, there is a difference between the diameter value measured by the diameter scanning unit 142 and a target diameter value, a pulling speed of the single crystal block can be set.

[0099] If the measured diameter is larger than the target diameter, the drawing speed can be adjusted to be higher than the current drawing speed. Conversely, if the measured diameter is smaller than the target diameter, the drawing speed can be adjusted to be lower than the current drawing speed.

[0100] The main control unit 140 can include the second drive unit 146.

[0101] The second drive unit can output a signal that causes the silicon single-crystal block to be pulled over the traction device 110. The second drive unit 146 can send data regarding a corrected traction speed value, generated in the traction speed determination unit 144, to the traction device 110.

[0102] The second drive unit 146 can be a servo motor for operating the second traction unit 112 by controlling the traction speed of the single crystal block that is currently being grown.

[0103] Consequently, the in Fig. Figures 7 to 9 of the single-crystal growing device of the embodiment comprise the auxiliary control for controlling the auxiliary heat shielding unit and the main control for controlling the pulling of the silicon single-crystal block, wherein the increase rate of the auxiliary heat shielding unit can be controlled such that the auxiliary heat shielding unit is located at a predetermined distance from the single-crystal block body section that is currently being grown.

[0104] Since the auxiliary heat shielding unit is controlled to maintain a predetermined distance from the silicon single-crystal block body section, a crystal defect area can be set by reducing a difference in the cooling rate between the center and the perimeter of the cross-section of the body section that is perpendicular to the elevation direction of the auxiliary heat shielding unit, and the distribution of a defect-free area in the body section can be increased.

[0105] The following describes embodiments of a silicon single-crystal growth process using the silicon single-crystal growth device of the embodiments described above.

[0106] In the following description of the embodiments, a repeated description of the embodiments of the silicon single-crystal growing device described above is omitted, and differences are described below.

[0107] A silicon single-crystal growth process according to one embodiment can be carried out in a silicon single-crystal growth apparatus comprising: a chamber, a crucible arranged in the chamber to hold a silicon melt, a heat shielding unit arranged in the chamber, and an auxiliary heat shielding unit arranged above the crucible such that it is vertically movable. The silicon single-crystal growth process includes the step of controlling the rate of increase of the auxiliary heat shielding unit such that the auxiliary heat shielding unit maintains a predetermined distance from a body section of the single-crystal block being grown in the silicon melt, in order to increase the distribution of a defect-free area in the body section of the single-crystal block.

[0108] In the silicon single-crystal growth process of the embodiment, the growth rate of the auxiliary heat shielding unit can be controlled in such a way that a temperature difference between the center and the circumference of the cross-section of the body section that is perpendicular to the growth direction of the auxiliary heat shielding unit is reduced.

[0109] Furthermore, the rate of increase of the auxiliary heat shielding unit can be controlled in such a way that a difference in the cooling rate between the center and the perimeter of the cross-section of the body section is reduced, and the difference in the cooling rate can be controlled in such a way that it is, for example, below 1 K / cm.

[0110] In this embodiment, the rate of increase of the auxiliary heat shielding unit, which is arranged above the crucible, can be controlled in such a way that heat loss from the silicon melt during the growth of the single-crystal block body section is prevented and rapid cooling of the single-crystal block is prevented, thereby reducing a temperature difference between the center and the periphery of the cross-section of the single-crystal block and the magnitude of a temperature gradient in the axial direction.

[0111] Consequently, reducing the magnitude of the temperature gradient can uniformly distribute the defect area radially along the single-crystal block. Furthermore, adjusting the temperature gradient can create a defect-free zone starting from the initial portion of the block, thereby increasing the distribution of defect-free areas within that block.

[0112] The rate of increase of the auxiliary heat shielding unit is controlled in particular such that the auxiliary heat shielding unit is spaced from the boundary of the shoulder section and the body section of the single crystal block by a distance ranging from 150 mm to 300 mm.

[0113] Furthermore, the increase rate of the auxiliary heat shielding unit can be controlled in the case where the length of the body section is less than or equal to 400 mm.

[0114] If the body section is grown to a length exceeding 400 mm, crystal growth within that section is more strongly influenced by the water cooling piping located in the upper part of the chamber than by the insulating effect of the auxiliary heat shield. Therefore, controlling the crystal defect area of ​​the single-crystal block using the auxiliary heat shield can be more effective if the heat shield is positioned between the silicon melt surface and the water cooling piping.

[0115] This means that once the auxiliary heat shielding unit has passed through the water cooling piping, the effect of adjusting the crystal defect area in the single crystal block by controlling the scaling rate of the auxiliary heat shielding unit may be reduced.

[0116] A silicon single-crystal growth process according to another embodiment can be carried out in a silicon single-crystal growth apparatus comprising: a chamber, a crucible arranged in the chamber to hold a silicon melt, a heat shielding unit arranged in the chamber, an auxiliary heat shielding unit arranged above the crucible such that it is vertically movable, a main control for controlling the pull rate of the single-crystal block being grown in the silicon melt, and an auxiliary control for controlling the pull rate of the auxiliary heat shielding unit. The silicon single-crystal growth process can include the steps of checking the length of a body section of the grown single-crystal block and determining, based on the checked length of the body section, whether or not the auxiliary heat shielding unit should be operated.

[0117] Fig. Figure 10 is a flowchart that illustrates one embodiment of the silicon single crystal growth process.

[0118] For example, the flowchart of the in Fig. Figure 10 of the silicon single-crystal growth process illustrates the step of controlling the increase rate of the auxiliary heat shielding unit and the pull rate of the single-crystal block by the main control and the auxiliary control.

[0119] Referring to Fig. 10. The silicon single-crystal growth method of the embodiment may include step S1000 of checking the length of the grown single-crystal block body section and assessing whether the tested length of the body section is less than or equal to 400 mm or not.

[0120] If the length of the body section in the silicon single-crystal growth process is less than or equal to 400 mm, the pulling of the single-crystal block can be controlled by the main control and the operation of the auxiliary heat shielding unit can be controlled by the auxiliary control.

[0121] At this time, the step of controlling the operation of the auxiliary heat shield unit by the auxiliary control may include: the step of checking the position of the body section and the position of the auxiliary heat shield unit, and step S1310 of calculating the distance value between the body section and the auxiliary heat shield unit based on the checked positions, step S1330 of assessing whether the calculated distance value is within a target distance value range or not, step S1350 of generating a correction value for the rise rate of the auxiliary heat shield unit if the distance value deviates from the target distance value range, and step S1370 of pulling the auxiliary heat shield unit based on the rise rate correction value.

[0122] At this time, the target distance between the body section and the auxiliary heat shielding unit can range from 150 mm to 300 mm. This means that a distance between the boundary of the heel section and the body section of the single crystal block currently being grown, and the lower surface of the auxiliary heat shielding unit, can be continuously maintained within the target distance range of 150 mm to 300 mm.

[0123] Furthermore, the step of controlling the operation of the auxiliary heat shielding unit by the auxiliary controller can include step S1360 of moving the auxiliary heat shielding unit upwards without a change in the current ascent rate if the distance between the body section and the auxiliary heat shielding unit is within the target distance value range.

[0124] However, if in step S1000, which involves checking the length of the body section of the grown single crystal block and assessing whether the checked length of the body section is less than or equal to 400 mm or not, the measured length of the body section is greater than 400 mm, the increase rate of the auxiliary heat shielding unit can be maintained at a rate greater than or equal to the pull rate of the single crystal block.

[0125] This means that the operation of the auxiliary heat shielding unit can include step S1210 of maintaining the increase rate of the auxiliary heat shielding unit so that it is greater than or equal to the pull rate of the silicon single crystal block.

[0126] For example, the growth rate of the auxiliary heat shielding unit in the process, after the silicon single-crystal block has been grown, such that the length of the body section is greater than or equal to 400 mm, can be maintained regardless of the distance between the auxiliary heat shielding unit and the body section, provided that the growth rate is greater than or equal to the pull rate of the silicon single-crystal block.

[0127] In the embodiment of the in Fig. In the silicon single-crystal growth process shown in section 10, the pulling speed of the single-crystal block can be controlled by the main control.

[0128] The step of controlling the pull rate of the single crystal block by the main control includes step S1100 of scanning the diameter of the single crystal block using a diameter scanning unit, step S1120 of calculating an error between a scanned diameter value and a target diameter value by the pull rate determination unit, step S1140 of generating a correction value of the pull rate based on the calculated value, and step S1160 of pulling the single crystal block with a pull rate changed depending on the correction value.

[0129] Consequently, this can be in Fig.10 illustrated silicon single-crystal growth methods of the embodiment extract the distance value between the body section of the single-crystal block and the auxiliary heat shielding unit and can control the growth rate of the auxiliary heat shielding unit based on the extracted distance value.

[0130] If the auxiliary control also controls the auxiliary heat shielding unit in such a way that it is maintained at a predetermined distance from the single crystal block, a crystal defect area can be set, and the distribution of a defect-free area in the body section can be increased by reducing a difference in the cooling rate between the center and the perimeter of the cross-section of the body section that is perpendicular to the increase rate of the auxiliary heat shielding unit.

[0131] In the case of the single-crystal growth device and the growth method of the embodiments described above, the provision of the auxiliary heat shielding unit during the initial growth of the body section of the single-crystal block can achieve an insulating effect. Furthermore, heat loss from the top of the crucible during the initial growth of the body section can be minimized, and the magnitude of the temperature gradient between the center and the periphery of the body section in the axial and radial directions can be reduced, thereby enabling a more uniform distribution of crystal defects and increasing the distribution of defect-free areas.

[0132] Although the exemplary embodiments have been presented and described as above, it will of course be obvious to people with technical knowledge that the embodiments are provided to aid understanding, and that the embodiments are not limited to the above description, and that various modifications and variations can be made to the embodiments without departing from the spirit or scope of the disclosure, and that the modifications and variations should not be understood individually in terms of the point of view or scope of the disclosure, as long as they include constituent elements set forth in the patent claims. Industrial applicability

[0133] A silicon single-crystal growing device and a growing method according to the embodiments can, as a result of arranging an auxiliary heat shielding unit above a melting crucible and controlling the rate of increase of the auxiliary heat shielding unit, control a defect area in the body section of a single-crystal block and can increase the distribution of a defect-free area, thus giving them industrial applicability.

Claims

[1] Silicon single crystal growth device comprising: - a chamber (10); - a melting pot (30) arranged in the chamber (10) to receive a silicon melt (SM); - a heater (20) arranged outside the melting pot (30) for heating the melting pot (30); - a heat shielding unit (40) arranged in the chamber (10); - an auxiliary heat shielding unit (70) arranged above the crucible (30) so as to be vertically movable; - a main controller (140) for controlling a pulling speed of a single crystal ingot (50) grown in the silicon melt (SM); - an auxiliary controller (130) for controlling an increasing speed of the auxiliary heat shielding unit (70); and - a pulling device (110) for pulling the single-crystal ingot and the auxiliary heat shielding unit (70) respectively based on a control signal supplied from the main controller (140) and the auxiliary controller (130), wherein the auxiliary heat shielding unit (70) has a truncated cone shape with a through opening, wherein the single crystal block (50) has a body portion (B) and a shoulder portion (S), and wherein the auxiliary heat shielding unit (70) is arranged above the boundary between the shoulder portion (S) and the body portion (B) of the single-crystal block (50) at a predetermined distance (d), wherein the predetermined distance (d) by which the auxiliary heat shielding unit (70) is spaced upward from a boundary of the shoulder portion (S) and the body portion (B) of the single crystal ingot (50) ranges from 150 mm to 300 mm, and wherein the elevating speed of the auxiliary heat shielding unit (70) is between 0.5 mm / min and 0.7 mm / min. [2] The apparatus of claim 1, wherein the auxiliary control (130) comprises: - a position value sensing unit (132) for detecting a position of a body portion (B) of the single crystal block (50) and a position of the auxiliary heat shielding unit (70); - a distance calculator (134) for calculating a distance between the body portion (B) and the auxiliary heat shielding unit (70) based on the positions of the body portion (B) and the auxiliary heat shielding unit (70) detected by the position value sensing unit (132); - a correction value generating means (136) for generating a correction value of the increasing speed of the auxiliary heat shielding unit (70) based on a value output by the distance calculator (134); and - a first drive unit (138) for outputting a changed increase speed based on the generated correction value to the traction device (110). [3] The apparatus according to claim 2, wherein said correction value generating means (136) generates the correction value to allow said auxiliary heat shielding unit (70) to maintain said predetermined distance (d) from said body portion (B) of said single crystal ingot (50). [4] The apparatus according to claim 3, wherein the predetermined distance (d) is controlled in consideration of growth conditions for the body portion (B) of the single crystal ingot (50). [5] The apparatus of claim 2, wherein the main controller (140) comprises: - a diameter sensing unit (142) for detecting a diameter of the single crystal block (50); - a pulling speed determining unit (144) for determining the pulling speed of the single-crystal ingot (50) based on a diameter value detected by the diameter sensing unit (142); and - a second drive unit (146) for outputting a specific train speed value to the traction device (110). [6] Device according to claim 1, wherein the pulling device (110) comprises: - a first pulling unit (114) connected to an upper surface of the auxiliary heat shielding unit via a first wire (72); and - a second pulling unit (112) connected to the single crystal block (50) via a second wire (52). [7] A silicon single crystal growth process carried out in a silicon single crystal growth apparatus comprising: - one chamber (10), - a melting pot (30) arranged in the chamber (10) to receive a silicon melt (SM), - a heat shielding unit (40) arranged in the chamber (10), and - an auxiliary heat shielding unit (70) arranged above the crucible (30) so as to be vertically movable, the method comprising: Controlling an increase speed of the auxiliary shielding unit (70) such that the auxiliary heat shielding unit (70) maintains a predetermined distance (d) from a body portion (B) of a single crystal block (50) grown in the silicon melt (SM) in order to increase a distribution of a defect-free region in the body portion (B) of the single crystal block (50), wherein the auxiliary heat shielding unit (70) has a truncated cone shape with a through-hole, and wherein the pulling speed for the auxiliary heat shielding unit (70) is controlled such that the auxiliary heat shielding unit (70) is arranged above the boundary between a shoulder portion (S) and a body portion (B) of the single-crystal ingot (50) at a predetermined distance (d), the predetermined distance (d) ranging from 150 mm to 300 mm, and wherein the elevation speed of the auxiliary heat shielding unit (70) is between 0.5 mm / min and 0.7 mm / min. [8] The method according to claim 7, wherein the raising speed of the auxiliary heat shielding unit (70) is controlled such that a temperature difference between a center and a periphery of a cross section of the body portion (B) perpendicular to a raising direction of the auxiliary heat shielding unit (70) is reduced. [9] The method according to claim 7, wherein the raising speed of the auxiliary heat shielding unit (70) is controlled such that a difference in cooling rate between a center and a circumference of a cross section of the body portion (B) perpendicular to a raising direction of the auxiliary heat shielding unit (70) is reduced. [10] The method of claim 9, wherein the difference in cooling rate is less than 1 K / cm. [11] The method according to claim 7, wherein the elevating speed of the auxiliary heat shielding unit (70) is controlled when a length of the body portion is less than or equal to 400 mm. [12] The method of claim 7, further comprising: - detecting a diameter of the single crystal block (50); - determining the pulling speed of the single-crystal block (50) based on the detected diameter; and - Outputting a specific train speed to a pulling device (110). [13] The method according to claim 7, wherein the predetermined distance (d) is controlled taking into account growth conditions for the body portion (B) of the single crystal block (50).

Images