JP2013139364A - Device for assisting with setting of condition for pulling silicon single crystal using silica glass crucible - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate setting of pulling conditions of single crystal silicon better adapted to characteristic of respective silica glass crucibles.SOLUTION: Measurement data for three-dimensional shapes of silica glass crucibles used by a user are acquired. Next simulation is carried out on incidence of crystal defects in case of conducting pulling of silicon single crystal by the Czochralski method using a silica glass crucible with three-dimensional shapes just the same as the measurement data, thereby pulling conditions, with which the rate of incidence of crystal defects becomes below the predetermined standard, are established. Subsequently, the pulling conditions, with which the rate of incidence of crystal defects becomes below the predetermined standard, are provided to the user. As a result, the user can easily set pulling conditions of single crystal silicon better adapted to characteristic of respective silica glass crucibles.

Description

  The present invention relates to an apparatus for assisting in setting conditions for pulling a silicon single crystal using a silica glass crucible.

  In order to produce a silicon single crystal by using a silica glass crucible by a Czochralski (hereinafter referred to as CZ) method, a solid-liquid interface shape between a solid silicon single crystal and a liquid silicon melt, A method for numerical analysis of the temperature distribution in the vicinity of the solid-liquid interface by computer simulation has been vigorously developed.

  For example, in Patent Document 1, physical property values of each member of a hot zone modeled with a mesh structure are input to a computer, and the surface temperature distribution of each member is obtained based on the amount of heat generated by the heater and the radiation rate of each member. Is described.

JP 2009-190926 A

  However, it is difficult to use the prior art described in the above-mentioned literature for setting the pulling conditions of single crystal silicon suitable for the characteristics of each silica glass crucible.

  The present invention has been made in view of the above circumstances, and an object thereof is to facilitate the setting of pulling conditions for single crystal silicon suitable for the characteristics of each silica glass crucible.

  ADVANTAGE OF THE INVENTION According to this invention, the apparatus which assists the condition setting of the silicon single crystal pulling using a silica glass crucible is provided. This apparatus includes a crucible specifying information acquisition unit for acquiring crucible specifying information that can individually specify a silica glass crucible input by a user, and measuring a three-dimensional shape of the silica glass crucible specified individually by the crucible specifying information. Using a measurement data acquisition unit for acquiring data and a calculation engine capable of one or more calculations selected from the group consisting of heat transfer calculation, fluid calculation, and structure calculation, silica glass having a three-dimensional shape according to the measurement data A simulation unit that obtains simulation data on the generation of crystal defects when a silicon single crystal is pulled using a crucible, and a pulling condition including a heating temperature, a pulling speed, and a rotation speed used by the simulation unit are set. The rate of occurrence of crystal defects in the simulation data obtained based on the pulling conditions of If it exceeds comprises a pulling condition setting unit for setting the improved pulling conditions the incidence of the crystal defect is equal to or less than a predetermined level, an output unit for outputting the pulling conditions, the.

  According to this configuration, after the silica glass crucible input by the user is individually specified, simulation is performed based on the measurement data of the three-dimensional shape of the silica glass crucible, and the occurrence rate of crystal defects is a predetermined level. It is possible to output the following conditions for improving the improvement. Therefore, the user can easily set pulling conditions for single crystal silicon suitable for the characteristics of each silica glass crucible.

  Moreover, according to the present invention, there is provided an apparatus for assisting in setting conditions for pulling a silicon single crystal using another silica glass crucible. This apparatus includes a crucible specifying information acquisition unit for acquiring crucible specifying information that can individually specify a silica glass crucible input by a user, and measuring a three-dimensional shape of the silica glass crucible specified individually by the crucible specifying information. A measurement data acquisition unit for acquiring data and an output unit for outputting the measurement data are provided.

  According to this configuration, after the silica glass crucible input by the user is individually specified, measurement data of the three-dimensional shape of the silica glass crucible is output. Therefore, the user can easily set pulling conditions for single crystal silicon suitable for the characteristics of each silica glass crucible based on the measurement data of the three-dimensional shape of the silica glass crucible.

  According to the present invention, it is possible to easily set pulling conditions for single crystal silicon suitable for the characteristics of each silica glass crucible.

It is a conceptual diagram for demonstrating the operation principle of the apparatus of this embodiment. Using the measurement data of the three-dimensional shape of the silica glass crucible obtained by using the apparatus of the present embodiment, it will be described that the user appropriately charges and melts the polycrystalline silicon raw material in the single crystal silicon pulling process. It is a conceptual diagram for. In order to explain that the user performs feedback control of the heating temperature, the pulling speed, and the rotational speed in the pulling process of the single crystal silicon more precisely using the pulling condition data obtained by using the apparatus of the present embodiment. FIG. It is a functional block diagram for demonstrating the whole structure of the apparatus of this embodiment. It is a functional block diagram for demonstrating the detailed structure of the simulation part of the apparatus of this embodiment, and a raising condition setting part. It is a data table for demonstrating the data structure of the measurement data of the silica glass crucible used with the apparatus of this embodiment. It is a flowchart for demonstrating operation | movement of the apparatus of this embodiment. It is a measurement process figure for demonstrating the method of measuring the measurement data of the silica glass crucible used with the apparatus of this embodiment using a robot arm and a ranging part. It is a conceptual diagram for demonstrating the measurement principle in FIG. It is a graph which shows the measurement result of the internal ranging part in FIG. It is a graph which shows the measurement result of the external ranging part in FIG.

<Apparatus for supporting setting of manufacturing conditions for silica glass crucible>
FIG. 1 is a conceptual diagram for explaining the operation principle of the apparatus according to the present embodiment. In this embodiment, first, using a silica glass crucible manufacturing apparatus equipped with a power source, a carbon electrode, a carbon mold, a decompression mechanism, etc., silica powder (also referred to as quartz powder) laminated on the mold is melted. A silica glass crucible is manufactured. Specifically, a silica powder layer forming step of depositing silica powder having an average particle size of about 300 μm on the inner surface of the rotary mold to form a silica powder layer, and the silica powder layer while reducing the pressure of the silica powder layer from the mold side A silica glass crucible is produced by an arc melting step of forming a silica glass layer by arc melting.

  At this time, at the initial stage of the arc melting process, the silica powder layer is strongly depressurized to remove bubbles to form a transparent layer, and then the depressurization is weakened to form a bubble-containing layer in which bubbles remain. A two-layered silica glass crucible having a transparent layer on the inner surface side and a bubble-containing layer on the outer surface side can be formed.

  Next, the three-dimensional shape of the silica glass crucible is measured using a robot arm to be described later to obtain measurement data of the three-dimensional shape of the silica glass crucible.

  Then, according to a user's request | requirement, the measurement data of the three-dimensional shape of this silica glass crucible are provided.

  Then, by performing a simulation on the generation of crystal defects when a silicon single crystal is pulled by the Czochralski method using a silica glass crucible having a three-dimensional shape according to the measurement data, the occurrence rate of crystal defects is a predetermined value. Set up pulling conditions that are below the level. Subsequently, the user is provided with a pulling condition that causes the occurrence rate of the crystal defects to be a predetermined level or less. As a result, the user can easily set pulling conditions for single crystal silicon suitable for the characteristics of each silica glass crucible.

  FIG. 2 shows that the user appropriately charges and melts the polycrystalline silicon raw material in the pulling process of the single crystal silicon using the measurement data of the three-dimensional shape of the silica glass crucible obtained by using the apparatus of the present embodiment. It is a conceptual diagram for demonstrating this. At the time of pulling up the silicon single crystal, as shown in FIG. 2A, the crucible 11 is filled with the polycrystalline silicon 21, and in this state, the polycrystalline silicon is heated by the carbon heater disposed around the crucible 11. By melting, a silicon melt 23 is obtained as shown in FIG.

  Since the volume of the silicon melt 23 is determined by the mass of the polycrystalline silicon 21, the height position H of the liquid surface 23 a of the silicon melt 23 depends on the mass of the polycrystalline silicon 21 and the three-dimensional shape of the inner surface of the crucible 11. Determined. According to the present embodiment, since the measurement data of the three-dimensional shape of the inner surface of the crucible 11 is provided, the volume up to an arbitrary height position of the crucible 11 is specified, and accordingly, the silicon melt 23 liquid surface 23a is specified. A height position H is determined. After the height position H of the initial liquid surface of the silicon melt 23 is determined, the tip of the seed crystal is lowered to the height position H to come into contact with the silicon melt 23, and then slowly pulled up to form silicon. Single crystals can be produced.

  FIG. 3 shows that the user performs more precise feedback control of the heating temperature, pulling speed, and rotation speed in the pulling process of the single crystal silicon using the pulling condition data obtained by using the apparatus of the present embodiment. It is a conceptual diagram for demonstrating. When pulling up the silicon single crystal, the crucible 11 is filled with polycrystalline silicon, and in this state, the polycrystalline silicon is heated and melted by the carbon heater disposed around the crucible 1, and is shown in FIG. Thus, the silicon melt 23 is obtained.

  Since the volume of the silicon melt 23 is determined by the mass of the polycrystalline silicon 21, the initial height position H 0 of the liquid surface 23 a of the silicon melt 23 is three-dimensional between the mass of the polycrystalline silicon 21 and the inner surface of the crucible 11. It depends on the shape. According to the present embodiment, since the measurement data of the three-dimensional shape of the inner surface of the crucible 11 is provided, the volume up to an arbitrary height position of the crucible 11 is specified, and accordingly, the silicon melt 23 liquid surface 23a is specified. An initial height position H0 is determined.

  After the initial height position H0 of the liquid surface 23a of the silicon melt 23 is determined, the tip of the seed crystal 24 is lowered to the height position H0 as shown in FIG. Then, the silicon single crystal 25 is pulled up slowly by pulling it up according to pulling conditions including the heating temperature, pulling speed and rotation speed provided in this embodiment.

  As shown in FIG. 3B, when the straight body part (part having a constant diameter) of the silicon single crystal 25 is pulled up, the liquid level 23a is positioned on the side wall part 11a of the crucible 11. According to the pulling conditions including the heating temperature, the pulling speed and the rotation speed provided in this embodiment, the descent speed V of the liquid level 23a becomes almost constant when the pulling speed is raised at a constant speed, so that the pulling control is easy. .

  However, as shown in FIG. 1 (c), when the liquid level 23a reaches the round part 11b of the crucible 11, the area rapidly decreases as the liquid level 23a descends. Increases rapidly. The descending speed V depends on the inner surface shape of the round part 11b, but since the inner surface shape is slightly different for each crucible, it is not possible to grasp in advance how the descending speed V changes. It was difficult and hindered automated lifting.

  In the present embodiment, since the three-dimensional shape of the inner surface of the crucible is accurately measured by a method described later, the inner surface shape of the round portion 11b (round portion unevenness data) is known in advance, and accordingly, the descent speed V Can be accurately predicted, and based on the prediction, by determining the pulling conditions such as the pulling speed of the silicon single crystal 25 and providing it to the user, the round portion 11b It is possible to prevent metastasis and automate the pulling.

  FIG. 4 is a functional block diagram for explaining the overall configuration of the apparatus of the present embodiment. The manufacturing condition setting support apparatus 1000 is provided with a crucible specifying information acquisition unit 140 that acquires crucible specifying information that can individually specify a silica glass crucible input by a user. The crucible specifying information acquisition unit 140 acquires information that can individually specify the silica glass crucible such as the type, manufacturing lot, and serial number of the silica glass crucible input by the user through the user terminal 152 via the Internet 150 and the local LAN 118. May be.

  The manufacturing condition setting support apparatus 1000 is provided with a measurement data acquisition unit 102 that acquires measurement data of a three-dimensional shape of a silica glass crucible individually specified by the crucible specifying information. The measurement data acquisition unit 102 may acquire measurement data of the three-dimensional shape of the silica glass crucible stored in the external server 126 via the local area LAN 118.

  This manufacturing condition setting support device 1000 uses a calculation engine capable of one or more types selected from the group consisting of heat transfer calculation, fluid calculation and structure calculation, and uses a three-dimensional shape silica according to the above measurement data. A simulation unit 112 is provided for obtaining simulation data regarding the occurrence of crystal defects when a silicon single crystal is pulled using a glass crucible.

  In this manufacturing condition setting support apparatus 1000, pulling conditions including the heating temperature, pulling speed and rotation speed used by the simulation unit 112 are set, and crystal defects of simulation data obtained based on the initial pulling conditions are set. In the case where the occurrence rate of the crystal defect exceeds a predetermined level, a pulling condition setting unit 114 is provided for setting an improved pulling condition that causes the crystal defect occurrence rate to be equal to or lower than the predetermined level.

  The manufacturing condition setting support apparatus 1000 is provided with an output unit 116 that outputs the above pulling conditions. The output unit 116 can output the measurement data of the three-dimensional shape of the silica glass crucible or the pulling conditions of the silicon single crystal to the user terminal 152 via the local area LAN 118 and the Internet 150.

  FIG. 5 is a functional block diagram for explaining detailed configurations of the simulation unit and the lifting condition setting unit of the apparatus according to the present embodiment. As shown in this figure, the simulation unit 112 is provided with a calculation engine storage unit 210 for storing a heat transfer calculation engine 204, a fluid calculation engine 206, a structural calculation engine 208, and the like. The simulation unit 112 reads the heat transfer calculation engine 204, the fluid calculation engine 206, and the structural calculation engine 208 from the calculation engine storage unit 210, and performs numerical analysis such as stress analysis and thermal fluid analysis. 202 is also provided.

  The simulation unit 112 uses a silica glass crucible having a three-dimensional shape according to measurement data, using a calculation engine capable of one or more calculations selected from the group consisting of heat transfer calculation, fluid calculation, and structure calculation. A crystal defect prediction unit 106 that predicts the generation of crystal defects when the silicon single crystal is pulled is provided. The crystal defect prediction unit 106 uses a calculation engine capable of one or more types selected from the group consisting of heat transfer calculation, fluid calculation, and structural calculation, to obtain a silica glass crucible having a three-dimensional shape as measured data. There is provided a crystal structure calculation unit 402 for performing a simulation of the crystal structure when the silicon single crystal is pulled up. In addition, the simulation unit 112 is provided with a threshold storage unit 404 that stores a predetermined level (threshold) that the crystal defect occurrence rate should not exceed.

  On the other hand, the pulling condition setting unit 114 is provided with a default pulling condition setting unit 310 that sets pulling conditions including the heating temperature, pulling speed, and rotation speed used by the simulation unit 112 as default pulling conditions. . The default pulling condition setting unit 310 reads from the default storage unit 312 default pulling conditions that are generally used in the case of the type of the silica glass crucible. In the pulling condition setting unit 114, the crystal defect occurrence rate of the simulation data obtained based on the initial pulling condition exceeds a predetermined level (threshold value) stored in the threshold storage unit 404. In such a case, an improved pulling condition setting unit 308 is provided for setting an improving pulling condition that causes the occurrence rate of crystal defects to be a predetermined level or less. The improved pulling condition setting unit 308 includes a heating temperature setting unit 302, a pulling speed setting unit 304, and a rotation number setting unit that respectively set pulling conditions including the heating temperature, the pulling speed, and the rotation number used by the simulation unit 112. 306 is provided. The improved pulling condition setting unit 308 considers individual measurement data of the three-dimensional shape of the silica glass crucible and additional information described later when the incidence of crystal defects exceeds a predetermined level under the default pulling condition. Then, an improvement pulling condition is set so that the occurrence rate of crystal defects is below a predetermined level.

  Here, returning to FIG. 4, the manufacturing condition setting support device 1000 is applied with the polycrystalline silicon raw material, the diameter of the pulling device (or the manufacturer name, series name, etc.) of the pulling device inputted by the user. Strength of the magnetic field (including the presence or absence of magnetic field input), the size of the silicon single crystal to be pulled up, the length of the silicon single crystal to be pulled up, the heating method (high frequency induction, carbon heater, etc.), the type of atmospheric gas (argon, nitrogen, Additional information acquisition unit for acquiring one or more types of additional information selected from the group consisting of hydrogen gas, etc., atmospheric gas pressure reduction, continuous pulling conditions, additional raw material charging conditions, and storage conditions (weather conditions, storage periods, etc.) 104 is further provided. The weather condition is important information because humidity and temperature are effective (cracks spread) on the crucible being stored. The additional information acquisition unit 104 may acquire the additional information input by the user at the user terminal 152 via the Internet 150 and the local area LAN 118.

  In consideration of such additional information, when the simulation unit 112 predicts the occurrence of crystal defects when the silicon single crystal is pulled, the accuracy of the simulation is further improved. Therefore, the lifting condition setting unit 114 can set more appropriate lifting conditions. As a result, the user can more easily set pulling conditions for single crystal silicon suitable for the characteristics of each silica glass crucible.

  FIG. 6 is a data table for explaining the data structure of the measurement data of the silica glass crucible used in the apparatus of this embodiment. As shown in this figure, the crucible measurement data acquisition unit 102 can directly acquire measurement data having a data structure as shown in this figure from the measurement device 128 described later via the local LAN 118. In this measurement data, for each position A, position B, position C, position D, position E, data such as inner XYZ coordinates, outer XYZ coordinates, bubble content, FT-IR spectrum, Raman spectrum, surface roughness, etc. Are recorded in table format.

  FIG. 7 is a flowchart for explaining the operation of the apparatus of this embodiment. First, the power of the manufacturing condition setting support apparatus 1000 is turned on and a series of operations is started. Then, first, the crucible identification information acquisition unit 104 sends information that can individually identify the silica glass crucible such as the type, manufacturing lot, and serial number of the silica glass crucible input by the user through the user terminal 152 through the Internet 150 and the local LAN 118. (S102). Then, the measurement data acquisition part 102 acquires the measurement data of the three-dimensional shape of the silica glass crucible stored in the external server 126 via the local area LAN 118 (S104).

  On the other hand, the additional information acquisition unit 104 has a crystal silicon raw material input by the user at the user terminal 152, the diameter of the pulling device, the strength of the applied magnetic field, the size of the silicon single crystal to be pulled up, the length of the silicon single crystal to be pulled up, Additional information such as the heating method, the type of atmospheric gas, the degree of decompression of the atmospheric gas, the continuous pulling condition, the additional raw material charging condition, and the storage condition is acquired via the Internet 150 and the local LAN 118 (S106).

  Thereafter, the simulation unit 112 uses a calculation engine capable of one or more calculations selected from the group consisting of heat transfer calculation, fluid calculation, and structural calculation to obtain a silica glass crucible having a three-dimensional shape according to the measurement data. Simulation data is obtained regarding the occurrence of crystal defects when the silicon single crystal is pulled using the silicon crystal (S108).

  Then, the pulling condition setting unit 114 sets pulling conditions including the heating temperature, pulling speed, and rotation speed used by the simulation unit 112, and crystal defects in simulation data obtained based on the initial pulling conditions It is determined whether or not the occurrence rate exceeds a predetermined level (S110). As a result, the pulling condition setting unit 114 sets an improved pulling condition that causes the crystal defect occurrence rate to be equal to or lower than the predetermined level when the crystal defect occurrence rate exceeds the predetermined level (S112). . On the other hand, the pulling condition setting unit 114 uses the pulling condition as it is when the occurrence rate of crystal defects is below a predetermined level.

  Then, the output unit 116 outputs the measurement data of the three-dimensional shape of the silica glass crucible or the pulling condition of the silicon single crystal to the user terminal 152 via the local LAN 118 and the Internet 150 (S114). Thus, a series of operations is completed.

<Three-dimensional shape measuring device for silica glass crucible>
Hereinafter, the three-dimensional shape measurement method of the silica glass crucible for obtaining the measurement data of the three-dimensional shape of the silica glass crucible used in the above embodiment will be described with reference to FIGS.

<Silica glass crucible>
FIG. 8 is a measurement process diagram for explaining a method of measuring the measurement data of the silica glass crucible used in the apparatus of this embodiment using a robot arm and a distance measuring unit. The silica glass crucible 11 to be measured has a transparent layer 13 on the inner surface side and a bubble-containing layer 15 on the outer surface side, and is mounted on a turntable 9 that can be rotated so that the opening portion faces downward. Is placed. The silica glass crucible 11 has a round part 11b having a relatively large curvature, a cylindrical side wall part 11a having an edge opened on the upper surface, and a mortar-shaped bottom part 11c made of a straight line or a curve having a relatively small curvature. In this embodiment, a round part is a part which connects the side wall part 11a and the bottom part 11c, from the point where the tangent of the curve of the round part overlaps with the side wall part 11a of the silica glass crucible, to the point having a common tangent with the bottom part 11c. Means the part. In other words, the point where the side wall part 11a of the silica glass crucible 11 starts to bend is the boundary between the side wall part 11a and the round part 11b. Further, the portion where the curvature of the bottom of the crucible is constant is the bottom portion 11c, and the point where the curvature starts to change when the distance from the center of the bottom of the crucible increases is the boundary between the bottom portion 11c and the round portion 11b.

<Internal robot arm, internal ranging unit>
On the base 1 provided at a position covered with the crucible 11, an internal robot arm 5 is installed. The internal robot arm 5 includes a plurality of arms 5a, a plurality of joints 5b that rotatably support these arms 5a, and a main body 5c. The main body 5c is provided with an external terminal (not shown) so that data exchange with the outside is possible. An internal distance measuring unit 17 for measuring the inner surface shape of the crucible 11 is provided at the tip of the internal robot arm 5. The internal distance measuring unit 17 measures the distance from the internal distance measuring unit 17 to the inner surface of the crucible 11 by irradiating the inner surface of the crucible 11 with laser light and detecting reflected light from the inner surface. A control unit that controls the joint 5b and the internal distance measuring unit 17 is provided in the main body 5c. The control unit moves the internal distance measuring unit 17 to an arbitrary three-dimensional position by rotating the joint 5b and moving the arm 5 based on a program provided in the main body 5c or an external input signal. Specifically, the internal distance measuring unit 17 is moved in a non-contact manner along the inner surface of the crucible. Therefore, rough shape data of the inner surface of the crucible is given to the control unit, and the position of the internal distance measuring unit 17 is moved according to the data. More specifically, for example, the measurement is started from a position close to the vicinity of the opening of the crucible 11 as shown in FIG. 8A, and toward the bottom 11c of the crucible 11 as shown in FIG. 8B. The internal distance measuring unit 17 is moved to perform measurement at a plurality of measurement points on the movement path. The measurement interval is, for example, 1 to 5 mm, for example, 2 mm. The measurement is performed at a timing stored in the internal distance measuring unit 17 in advance or according to an external trigger. The measurement results are stored in the storage unit in the internal distance measuring unit 17, and are sent to the main body unit 5c collectively after the measurement is completed, or are sequentially sent to the main body unit 5c for each measurement. The internal distance measuring unit 17 may be configured to be controlled by a control unit provided separately from the main body 5c.

  When the measurement from the opening of the crucible to the bottom 11c is completed, the turntable 9 is slightly rotated and the same measurement is performed. This measurement may be performed from the bottom 11c toward the opening. The rotation angle of the turntable 9 is determined in consideration of accuracy and measurement time, and is, for example, 2 to 10 degrees. If the rotation angle is too large, the measurement accuracy is not sufficient, and if it is too small, it takes too much measurement time. The rotation of the turntable 9 is controlled based on a built-in program or an external input signal. The rotation angle of the turntable 9 can be detected by a rotary encoder or the like. The rotation of the turntable 9 is preferably interlocked with the movement of the internal distance measuring unit 17 and the external distance measuring unit 19 described later, so that the three-dimensional coordinates of the internal distance measuring unit 17 and the external distance measuring unit 19 can be changed. Calculation becomes easy.

As will be described later, the internal distance measuring unit 17 includes a distance from the internal distance measuring unit 17 to the inner surface (inner surface distance) and a distance from the inner distance measuring unit 17 to the interface between the transparent layer 13 and the bubble-containing layer 15 (interface). Both distances can be measured. Since the angle of the joint 5b is known by a rotary encoder or the like provided in the joint 5b, the three-dimensional coordinates and direction of the position of the internal distance measuring unit 17 at each measurement point are known. Is obtained, the three-dimensional coordinates on the inner surface and the three-dimensional coordinates on the interface are known. And since the measurement from the opening part of the crucible 11 to the bottom part 11c is performed over the perimeter of the crucible 11, the three-dimensional shape of the inner surface of the crucible 11 and the three-dimensional shape of the interface become known. Further, since the distance between the inner surface and the interface is known, the thickness of the transparent layer 13 is also known, and a three-dimensional distribution of the thickness of the transparent layer is obtained.
Since the separation is known, the thickness of the transparent layer 13 is also known, and a three-dimensional distribution of the thickness of the transparent layer is obtained.

<External robot arm, external distance measuring unit>
An external robot arm 7 is installed on a base 3 provided outside the crucible 11. The external robot arm 7 includes a plurality of arms 7a, a plurality of joints 7b that rotatably support these arms, and a main body portion 7c. The main body 7c is provided with an external terminal (not shown) so that data exchange with the outside is possible. An external distance measuring unit 19 that measures the outer surface shape of the crucible 11 is provided at the tip of the external robot arm 7. The external distance measuring unit 19 measures the distance from the external distance measuring unit 19 to the outer surface of the crucible 11 by irradiating the outer surface of the crucible 11 with laser light and detecting the reflected light from the outer surface. A control unit that controls the joint 7b and the external distance measuring unit 19 is provided in the main body 7c. The control unit moves the external distance measuring unit 19 to an arbitrary three-dimensional position by rotating the joint 7b and moving the arm 7 based on a program provided in the main body unit 7c or an external input signal. Specifically, the external distance measuring unit 19 is moved in a non-contact manner along the outer surface of the crucible. Therefore, rough shape data of the outer surface of the crucible is given to the control unit, and the position of the external distance measuring unit 19 is moved according to the data. More specifically, for example, the measurement is started from a position close to the vicinity of the opening of the crucible 11 as shown in FIG. 8A, and toward the bottom 11c of the crucible 11 as shown in FIG. 8B. The external distance measuring unit 19 is moved to perform measurement at a plurality of measurement points on the movement path. The measurement interval is, for example, 1 to 5 mm, for example, 2 mm. The measurement is performed at a timing stored in advance in the external distance measuring unit 19 or according to an external trigger. The measurement results are stored in the storage unit in the external distance measuring unit 19 and are collectively sent to the main unit 7c after the measurement is completed, or are sequentially sent to the main unit 7c every measurement. The external distance measuring unit 19 may be configured to be controlled by a control unit provided separately from the main body unit 7c.

  The internal distance measuring unit 17 and the external distance measuring unit 19 may be moved in synchronization. However, since the measurement of the inner surface shape and the measurement of the outer surface shape are performed independently, it is not always necessary to synchronize.

  The external distance measuring unit 19 can measure the distance (outer surface distance) from the external distance measuring unit 19 to the outer surface. Since the angle of the joint 7b is known by a rotary encoder or the like provided in the joint 7b, the three-dimensional coordinates and direction of the position of the external distance measuring unit 19 are known. The three-dimensional coordinates are known. And since the measurement from the opening part of the crucible 11 to the bottom part 11c is performed over the perimeter of the crucible 11, the three-dimensional shape of the outer surface of the crucible 11 becomes known. From the above, since the three-dimensional shape of the inner surface and the outer surface of the crucible becomes known, a three-dimensional distribution of the wall thickness of the crucible is obtained.

<Details of distance measurement>
Next, details of distance measurement by the internal distance measuring unit 17 and the external distance measuring unit 19 will be described with reference to FIG.
As shown in FIG. 9, the internal distance measuring unit 17 is disposed on the inner surface side (transparent layer 13 side) of the crucible 11, and the external distance measuring unit 19 is disposed on the outer surface side (bubble-containing layer 15 side) of the crucible 11. Placed in. The internal distance measuring unit 17 includes an emitting unit 17a and a detecting unit 17b. The external distance measuring unit 19 includes an emitting unit 19a and a detecting unit 19b. The internal distance measuring unit 17 and the external distance measuring unit 19 include a control unit and an external terminal (not shown). The emitting portions 17a and 19a emit laser light, and include, for example, a semiconductor laser. The wavelength of the emitted laser light is not particularly limited, but is, for example, red laser light having a wavelength of 600 to 700 nm. The detectors 17b and 19b are composed of, for example, a CCD, and the distance to the target is determined based on the principle of triangulation based on the position where the light hits.

  A part of the laser light emitted from the emitting part 17a of the internal distance measuring part 17 is reflected by the inner surface (the surface of the transparent layer 13), and partly reflected by the interface between the transparent layer 13 and the bubble-containing layer 15, These reflected lights (inner surface reflected light and interface reflected light) strike the detection unit 17b and are detected. As is apparent from FIG. 8, the inner surface reflected light and the interface reflected light hit different positions of the detection unit 17b. Due to the difference in position, the distance from the inner distance measuring unit 17 to the inner surface (inner surface distance) and The distance to the interface (interface distance) is determined. A suitable incident angle θ may vary depending on the state of the inner surface, the thickness of the transparent layer 13, the state of the bubble-containing layer 15, etc., but is, for example, 30 to 60 degrees.

  FIG. 10 shows actual measurement results measured using a commercially available laser displacement meter. As shown in FIG. 10, two peaks are observed, the peak on the Near side corresponds to the peak due to the inner surface reflected light, and the peak on the Far side corresponds to the peak due to the interface reflected light. Thus, the peak due to the reflected light from the interface between the transparent layer 13 and the bubble-containing layer 15 is also clearly detected. Conventionally, the interface has not been specified in this way, and this result is very novel.

  If the distance from the internal distance measuring unit 17 to the inner surface is too far, or if the inner surface or interface is locally inclined, two peaks may not be observed. In that case, it is possible to search the position and angle at which two peaks are observed by bringing the internal distance measuring unit 17 closer to the inner surface or by tilting the internal distance measuring unit 17 to change the emission direction of the laser light. preferable. Further, even if the two peaks are not observed simultaneously, the peak due to the inner surface reflected light may be observed at a certain position and angle, and the peak due to the interface reflected light may be observed at another position and angle. In order to prevent the internal distance measuring unit 17 from coming into contact with the inner surface, a maximum proximity position is set so that even if no peak is observed, the inner distance measuring unit 17 cannot be closer to the inner surface than that position. preferable.

  In addition, when there are independent bubbles in the transparent layer 13, the internal distance measuring unit 17 may detect the reflected light from the bubbles, and the interface between the transparent layer 13 and the bubble-containing layer 15 may not be detected properly. is there. Therefore, when the position of the interface measured at a certain measurement point A is greatly deviated (exceeding a predetermined reference value) from the position of the interface measured at the preceding and following measurement points, the data at the measurement point A is It may be excluded. In that case, data obtained by performing measurement again at a position slightly deviated from the measurement point A may be employed.

  The laser light emitted from the emitting portion 19a of the external distance measuring section 19 is reflected by the surface of the outer surface (bubble-containing layer 15), and the reflected light (outer surface reflected light) strikes the detecting portion 19b and is detected. The distance between the external distance measuring unit 19 and the outer surface is determined based on the detection position on the detection unit 19b. FIG. 11 shows the actual measurement results measured using a commercially available laser displacement meter. As shown in FIG. 11, only one peak is observed. When the peak is not observed, the external distance measuring unit 19 is brought closer to the inner surface, or the external distance measuring unit 19 is tilted to change the emission direction of the laser light to search for the position and angle at which the peak is observed. Is preferred.

  The present inventors consider that it is essential to acquire data of the three-dimensional shape of the inner surface of the crucible and the three-dimensional distribution of the thickness of the transparent layer in order to improve the performance and quality control of the crucible. However, since the crucible is a transparent body, it is difficult to optically measure the three-dimensional shape. I tried to illuminate the inner surface of the crucible to acquire an image and analyze the image, but this method takes a very long time to analyze the image. It could not be used to measure the shape.

  In such a situation, the present inventors irradiated the laser beam from the oblique direction to the inner surface of the crucible, and in addition to the reflected light (inner surface reflected light) from the inner surface of the crucible, the transparent layer and the bubbles It was found that reflected light from the interface of the containing layer (interface reflected light) can also be detected. The interface between the transparent layer and the bubble-containing layer is a surface where the bubble content changes rapidly, but is not a clear interface such as the interface between air and glass. It was a surprising discovery that is detectable. And the apparatus which supports the silicon single crystal pulling condition setting using the silica glass crucible of the above-described embodiment is possible only after the development of such a three-dimensional shape measuring apparatus for the silica glass crucible. is there.

<Characteristic values associated with three-dimensional shape of silica glass crucible>
The measurement data may include characteristic value data associated with the three-dimensional shape of the silica glass crucible. As this characteristic value, for example, one or more characteristic values selected from bubble content, surface roughness, infrared absorption spectrum, and Raman spectrum can be suitably used.

  Regarding generation of crystal defects when the simulation unit 112 pulls up the silicon single crystal in consideration of one or more characteristic values selected from the bubble content, surface roughness, infrared absorption spectrum, and Raman spectrum. In the case of prediction, the accuracy of simulation is further improved. Therefore, the lifting condition setting unit 114 can set more appropriate lifting conditions. As a result, the user can more easily set pulling conditions for single crystal silicon suitable for the characteristics of each silica glass crucible.

<Method for determining the three-dimensional distribution of the bubble distribution in the crucible>
After the three-dimensional shape of the inner surface of the crucible is obtained, the bubble distribution is measured by measuring the bubble distribution at the crucible wall at the position corresponding to each measurement point at a plurality of measurement points on the three-dimensional shape. Determine the three-dimensional distribution. The method of measuring the bubble distribution at the crucible wall at each measurement point is not particularly limited as long as it is a non-contact type, but a confocal microscope that can selectively acquire information from the focused surface is used. In this case, a clear image that clearly shows the position of the bubble can be acquired, so that highly accurate measurement is possible. Further, by acquiring and synthesizing an image on the surface of each focal position while shifting the focal position, the three-dimensional arrangement of the bubbles can be understood and the size of each bubble can be known, so that the bubble distribution can be obtained. Methods for moving the focal position include (1) moving the crucible, (2) moving the probe, and (3) moving the objective lens of the probe.

  The arrangement of the measurement points is not particularly limited. For example, the measurement points are arranged at intervals of 5 to 20 mm in the direction from the opening to the bottom of the crucible, and at intervals of 10 to 60 degrees in the circumferential direction, for example. Specifically, for example, a confocal microscope probe is attached to the tip of the internal robot arm 5 and moved along the inner surface in a non-contact manner in the same manner as the internal distance measuring unit 17. When the internal distance measuring unit 17 is moved, only the rough three-dimensional shape of the inner surface is known, but the exact three-dimensional shape of the inner surface is not known. Therefore, based on the rough three-dimensional shape. Although the internal distance measuring unit 17 has been moved, since the accurate three-dimensional shape of the inner surface is known when measuring the bubble distribution, the distance between the inner surface and the probe when moving the confocal microscope probe is measured. Can be controlled with high accuracy.

  After the confocal microscope probe is moved from the opening to the bottom of the crucible and the bubble distribution is measured at a plurality of points on the movement path, the turntable 9 is rotated to change the bubble distribution in another part of the crucible 11. Measure. With such a method, the bubble distribution can be measured over the entire inner surface of the crucible, and the three-dimensional distribution of the crucible bubble distribution can be determined based on the measurement result.

<Method of determining the three-dimensional distribution of the surface roughness of the inner surface of the crucible>
After the three-dimensional shape of the inner surface of the crucible is obtained, the three-dimensional distribution is determined by measuring the surface roughness of the inner surface at a plurality of measurement points on the three-dimensional shape. The method for measuring the surface roughness at each measurement point is not particularly limited as long as it is a non-contact type, but it is highly accurate if a confocal microscope that can selectively acquire information from the focused surface is used. Measurement is possible. Further, if a confocal microscope is used, information on the detailed three-dimensional structure of the surface can be acquired, and the surface roughness can be obtained using this information. The surface roughness includes a center line average roughness Ra, a maximum height Rmax, and a ten-point average height Rz. Any of these may be adopted, and another parameter reflecting the surface roughness is adopted. May be. The arrangement of measurement points and the specific measurement method are the same as those in the above-described method for determining the three-dimensional distribution of the bubble distribution of the crucible.

<Method for determining the three-dimensional distribution of the infrared absorption spectrum of the inner surface of the crucible>
After the three-dimensional shape of the inner surface of the crucible is obtained, the three-dimensional distribution is determined by measuring the infrared absorption spectrum of the inner surface at a plurality of measurement points on the three-dimensional shape. The method of measuring the infrared absorption spectrum at each measurement point is not particularly limited as long as it is a non-contact type, but the reflected light is detected by irradiating infrared rays toward the inner surface. It can be measured by obtaining the spectral difference. The arrangement of measurement points and the specific measurement method are the same as those in the above-described method for determining the three-dimensional distribution of the bubble distribution of the crucible. The arrangement of measurement points and the specific measurement method are the same as those in the above-described method for determining the three-dimensional distribution of the bubble distribution of the crucible.

<Method of determining the three-dimensional distribution of the Raman spectrum of the inner surface of the crucible>
After the three-dimensional shape of the inner surface of the crucible is obtained, the three-dimensional distribution is determined by measuring the Raman spectrum of the inner surface at a plurality of measurement points on the three-dimensional shape. The method of measuring the Raman spectrum at each measurement point is not particularly limited as long as it is a non-contact type, but it can be measured by irradiating a laser beam toward the inner surface and detecting the Raman scattered light. The arrangement of measurement points and the specific measurement method are the same as those in the above-described method for determining the three-dimensional distribution of the bubble distribution of the crucible.

Claims (7)

An apparatus that supports the setting of conditions for pulling a silicon single crystal using a silica glass crucible,
A crucible specifying information acquisition unit for acquiring crucible specifying information capable of individually specifying the silica glass crucible input by the user;
A measurement data acquisition unit for acquiring measurement data of the three-dimensional shape of the silica glass crucible individually specified by the crucible specifying information;
Using a calculation engine capable of one or more calculations selected from the group consisting of heat transfer calculation, fluid calculation and structure calculation, pulling up a silicon single crystal using a three-dimensional silica glass crucible according to the measurement data. A simulation unit that obtains simulation data on the occurrence of crystal defects when performed;
The pulling conditions including the heating temperature, pulling speed and rotation speed used by the simulation unit are set, and the crystal defect occurrence rate of the simulation data obtained based on the initial pulling conditions exceeds a predetermined level. In this case, a pulling condition setting unit for setting an improved pulling condition that causes the occurrence rate of the crystal defects to be a predetermined level or less,
An output unit for outputting the pulling condition;
Comprising
apparatus. The apparatus of claim 1.
The measurement data includes characteristic value data associated with the three-dimensional shape of the silica glass crucible;
The simulation unit is configured to obtain simulation data on the occurrence of crystal defects when a silicon single crystal is pulled using a silica glass crucible having a three-dimensional shape and characteristic values according to the measurement data.
apparatus. The apparatus of claim 2.
The characteristic value is one or more characteristic values selected from bubble content, surface roughness, infrared absorption spectrum and Raman spectrum.
apparatus. In the apparatus in any one of Claims 1-3,
The measurement data includes irregularity data of the round part of the silica glass crucible,
The pulling conditions include a pulling speed, heating temperature and rotation time table near the round part,
apparatus. In the apparatus in any one of Claims 1-4,
The polycrystalline silicon raw material input by the user, the diameter of the pulling device, the strength of the applied magnetic field, the size of the silicon single crystal to be pulled up, the length of the silicon single crystal to be pulled up, the heating method, the type of the atmospheric gas, the atmospheric gas An additional information acquisition unit that acquires one or more additional information selected from the group consisting of a degree of decompression, continuous pulling conditions, additional raw material charging conditions, and storage conditions;
apparatus. In the apparatus in any one of Claims 1-5,
The front output unit is configured to further output the measurement data;
apparatus. An apparatus that supports the setting of conditions for pulling a silicon single crystal using a silica glass crucible,
A crucible specifying information acquisition unit for acquiring crucible specifying information capable of individually specifying the silica glass crucible input by the user;
A measurement data acquisition unit for acquiring measurement data of the three-dimensional shape of the silica glass crucible individually specified by the crucible specifying information;
An output unit for outputting the measurement data;
Comprising
apparatus.