JP6452098B2 - Large diameter CZ single crystal growth apparatus and growth method thereof - Google Patents

Description

  The present invention relates to a single crystal growth apparatus and a single crystal growth method.

  In the single crystal growth apparatus and the single crystal growth method, the CZ method has been generally used for manufacturing a semiconductor single wafer material and a single crystal material used as a single wafer for a single crystal silicon solar cell.

However, looking at the relationship between the diameter of the crucible used and the diameter of the crystal, a crucible having an inner diameter of about 600 mm or more is used for a Φ200 mm single crystal and an inner diameter of the crucible is about 600 mm for a Φ300 mm single crystal. That is, it was common to pull up a single crystal having a diameter of about one third of the crucible diameter.
Therefore, when the diameter of the single crystal is increased, a furnace in which a crucible having a large diameter is contained is required. When the crucible becomes large, the graphite crucible, the heater, and the heat insulating cylinder all increase, and there is a drawback that the single crystal manufacturing apparatus becomes large and the cost increases due to the introduction of a large apparatus.

  In addition, when a large crystal is grown with a small crucible, crystal growth from the crucible wall tends to occur. In this case, the crystal from the crucible that is reverse to the growing crystal is solidified and connected, so that the crystal falls and melts. This could cause liquid leakage and could cause a major accident such as a hydrogen explosion.

JP2000-281814 JP 2008-254946 A

HORIOKA Yukichi, “Practical Instrumentation Control in Single-Crystal Manufacturing Process” Kogyo Kogyosha “Instrumentation” March 1985 issue, separate pages

In Patent Document 1, two diameter measuring cameras for a small diameter and a large diameter are used for growing a large crystal. However, no measures are taken for crystal growth from the crucible wall, which is the biggest problem in the growth of large crystals. On the other hand, with respect to the position of the temperature sensor, the temperature at the bottom of the crucible is measured as in Patent Document 2, or the temperature of the melt surface is measured by a heater outer wall temperature or a two-color thermometer as in Non-Patent Document 1. The crystal growth was controlled by measuring. In this way, the above measures are sufficient if crystal growth of about one third of the crucible diameter is performed. Even so, the single crystal and the crucible wall crystal were connected, and crystal dropping accidents could occur even if infrequent, and the damage caused by damage to the in-furnace parts in that case was significant.
The problem to be solved by the present invention is that the diameter of the growing crystal, which has been restricted by the crucible diameter, is made large. Conventionally, it has been common to grow a single crystal having a diameter of about one third of the diameter of the crucible. For example, in a CZ furnace for growing a semiconductor single crystal, a crucible having an inner diameter of 600 mm has been used to grow a single crystal having a diameter of 200 mm. In the case of growing a single crystal having a diameter of 300 mm, a crucible having an inner diameter of 900 mm has been used. Therefore, since there was no growth of a single crystal having a diameter of 380 mm for a silicon part of a semiconductor process device, for example, from a crucible having an inner diameter of 600 mm, the crucible was increased in size when a large-diameter single crystal was required, and thus the in-furnace part was increased in size. As a result, the entire equipment of the single crystal growth furnace was increased in size, and the increase in the size of the crystal required immediate capital investment, which was accompanied by an increase in cost.

  In order to solve the above-mentioned problems, the present invention provides a temperature sensor for monitoring the boundary between the crucible and the melt, and constantly monitors the temperature of the boundary to monitor the crystal growth from the crucible. While it is possible to maintain a temperature at which no crystal nuclei are generated on the crucible wall at any time, even if crystal growth is detected here, crystal growth from the crucible wall due to temperature rise can be suppressed or nuclei can be dissolved. Therefore, safe crystal growth of large-diameter crystals can be performed. That is, since a large diameter crystal can be produced safely from the same crucible, there is an advantage that the cost can be significantly reduced. According to the present invention, a single crystal having a diameter of about 80% of the inner diameter of the crucible can be obtained.

  The single crystal growth method according to the present invention can be measured by a temperature measurement sensor at the boundary between the crucible wall and the melt in the furnace of the single crystal growth furnace. With this sensor, when crystal growth from the crucible wall occurs, the crystal growth can be quickly grasped, the growth can be suppressed, the growth can be eliminated, and the same crystal growth as the grown crystal diameter can be performed.

In the preceding item (0009), a large crystal having about 80% of the inner diameter of the crucible can be manufactured by using the single crystal growth method.
The temperature measurement sensor can be slid in the direction perpendicular to the melt surface to check the melt surface level.

      In the previous item (0009), the temperature measurement sensor can be slid in the direction perpendicular to the melt surface to check the melt surface level. If this liquid surface position information is used to control the melt surface level, the accuracy of the melt surface control can be improved. Conventionally, there has been a method for measuring the melt surface by reflecting the laser beam on the melt surface and measuring the melt surface based on the position of the reflected light. Not put into practical use.

      In the preceding paragraph (0009), the temperature measurement sensor may be slid in the vertical direction and the horizontal direction, and the temperature distribution measurement in the circumferential direction of the crucible may be performed on the boundary portion where the melt and the crucible contact. It is possible to control the temperature of the heater so as not to exceed the temperature limit at which crystal growth from the crucible wall occurs based on the measured temperature distribution in the region. Moreover, even if crystal growth occurs from the crucible wall at one end, the temperature range can be adjusted to the high temperature side before further supercooling occurs.

In the preceding paragraph (0012), the single crystal growth furnace is provided with a plurality of measurement windows, and each measurement window is provided with a temperature measurement sensor, and each temperature sensor is independently slid in the vertical and horizontal directions to be melted. You may measure the temperature distribution of the circumference of a crucible about the part which a liquid and a crucible contact. In particular, when the grown crystal obstructs the visual field, the plurality of sensor outputs respectively provided in the plurality of observation windows can function effectively together with the crystal growth.
Moreover, you may use the line sensor which arranged the sensor in the line form instead of performing sliding operation | movement. In this case, the position information of each element of the line sensor may be used as the position information, and the region information may be analyzed by a program to predict the crystal growth from the crucible wall and eliminate the growth. In addition, area information may be captured using an area sensor.

      In the preceding item (0011), the melt surface level obtained by confirming the melt level may be always maintained and controlled at a predetermined level.

      In the preceding paragraph (0011), the diameter of the crystal may be measured by sliding the temperature measurement sensor in a direction parallel to the melt surface. In this case, the amount of movement when the sensor position is first aligned with the position of one side surface of the crystal and then the sensor is translated to the other side surface directly corresponds to the crystal diameter. Although there is a method of measuring the crystal diameter with a region sensor through a lens system, the accuracy of the diameter measurement is poor due to the influence of the focal length and magnification, so that accuracy improvement can be measured by using the present invention. Furthermore, the measurement accuracy can be improved by increasing the magnification of the temperature sensor viewer, grasping the characteristics of the rotating crystal during just focus, and measuring the diameter at the same position of the rotating crystal.

      Furthermore, in the previous item (0015), the temperature measurement sensor may be moved in order to always set the distance from the melt surface of the temperature measurement sensor to the focal length.

      In any one of the above items (0009) to (0016), it is preferable to use a silica glass crucible having liquid crystallinity as a crucible for performing single crystal growth.

      In the preceding paragraph (0009), the sensor for measuring the temperature of the boundary between the crucible wall and the melt during crystal growth in the furnace of the single crystal growth furnace can monitor crystal growth from the crucible wall surface during crystal growth.

      In the preceding paragraph (0018), when the temperature measurement sensor detects crystal growth from the crucible wall surface, the temperature setting value is instantaneously increased by a specified temperature, for example, a set temperature of 1450 ° C. by 10 ° C. The rate is maintained at a low rate growth rate of 0 to 0.5 mm / min, and the growth crystal from the crucible wall is melted. This is a single crystal growth method capable of continuing the crystal growth of the same diameter as that of the straight body portion that has been grown up to a higher rate.

In the previous section (0013), the high temperature part and the low low temperature part are determined from the temperature distribution in the circumferential direction of the crucible measured by the temperature measurement sensor, the crucible rotation is modulated, and the part where there is crystal growth from the crucible is This is a single crystal growth method capable of slowly passing through the high temperature part.
Usually, the temperature in the vicinity of the heater electrode increases. The crystal growth from the crucible wall grows in the low temperature part and melts in the high temperature part each time it goes around, so the passage time of the high temperature part is long (slowly) and the low temperature region is short (fast) to pass from the crucible. Crystal growth can be stopped or dissolved.

      The single crystal growth apparatus of the present invention has a temperature measurement sensor for measuring the temperature at the boundary between the crucible wall and the melt in the furnace, and the output of this temperature sensor can be used for crystal growth control and crucible position control.

      In the preceding item (0021), the single crystal growth apparatus can produce a large crystal having a diameter of about 80% of the inner diameter of the crucible used for crystal growth. Since the single crystal growth operation can proceed without worrying about the risk of crystal growth from the crucible wall, the degree of supercooling that promotes crystal growth can be greatly controlled.

      In the preceding paragraph (0022), in the single crystal growth apparatus of the present invention, the temperature measurement sensor is provided so as to be slidable in the direction perpendicular to the melt surface, and the melt surface level can be confirmed. The surface position of the melt is directly related to diameter detection and diameter control during crystal growth. In particular, when the diameter is optically controlled as an image and diameter control is performed, a significant difference occurs.

      In the single crystal growth apparatus of the present invention according to the preceding item (0021), the temperature measurement sensor is provided so as to be slidable in the vertical direction and the horizontal direction. The temperature distribution in the circumferential direction can be measured. Since there is a temperature distribution in the circumferential direction of the crucible, grasping of the high temperature portion and the low temperature portion greatly depends on the residence time of each place in crystal growth from the crucible wall surface.

Furthermore, the single crystal growth apparatus of the present invention according to the preceding item (0024) is provided with a plurality of measurement windows, and the temperature measurement sensor provided in each measurement window can be slid in the vertical and horizontal directions. Thus, the temperature distribution in the circumferential direction of the crucible can be measured for the portion where the melt and the crucible contact.
During the growth of a single crystal, it may become the shadow of a sensor trying to see the crucible wall on each of the seed crystal, shoulder, and straight body. Therefore, when the temperature is monitored from the optimum place in some cases, it is preferable that measurement can be performed through a plurality of observation windows.

Furthermore, the single crystal growth apparatus of the present invention according to the preceding item (0009 to 0020) has a seed crystal rotation speed of 10 ± 0.5 rpm and a crucible rotation of 8 ± 2 rpm.
When the crucible rotation and the seed crystal rotation are low-speed rotation, crystal growth from the crucible wall tends to occur. On the other hand, even when the rotation of the seed crystal is relatively slow, the ridge line portion of the crystal may grow rapidly. For example, if the rotation of the seed crystal is reduced to 5 ± 0.5 rpm and the crucible rotation to 4 ± 0.5 rpm, crystal growth from the crucible and rapid growth of the ridge line portion of the single crystal are likely to occur. Since low-temperature convection from the bottom of the crucible rolls up just below the single crystal, it is appropriate for the single crystal growth that the seed crystal rotation speed which is the above condition is 10 ± 0.5 rpm and the crucible rotation is 8 ± 2 rpm. is there.

The single crystal growth apparatus of the present invention according to the preceding item (0023) can always maintain and control the melt surface level grasped by the temperature measurement sensor at a predetermined level.
When observing the crucible wall surface and the melt interface center, the crucible ascending / descending speed is controlled so as not to cause a deviation in the aim of the sensor. Since the inner shape of the crucible has a large variation, it is desirable to synchronize with the rotational speed for data collection and smooth the detected signal by a moving average method or the like.

In the single crystal growth apparatus of the present invention according to the preceding item (0023), the temperature measurement sensor is provided so as to be slidable in a direction parallel to the melt surface, whereby the diameter of the crystal can be measured.
The sliding movement of the temperature measurement sensor is effective for positioning the temperature sensor on the boundary between the crucible wall and the melt.

Furthermore, the single crystal growth apparatus of the present invention according to the preceding item (0028) has a moving mechanism for always setting the distance from the melt surface of the temperature measurement sensor on the focal length.
The adjustment of the focal length can be determined based on whether the aiming ring on the focus is clearly visible. Therefore, the focal length adjustment mechanism is important.

Moreover, in the single crystal growth apparatus of the present invention according to the preceding paragraphs (0021 to 0029), the crucible is a silica glass crucible having a liquid crystallinity.
By using the molten crucible, the silicon melt comes into contact with the crucible wall with a convex surface, so that the temperature decreases in the upward direction of the crucible, which is advantageous in suppressing crystal growth from the crucible. Also, since the boundary line is clear, there is an advantage that it is easy to measure.

Further, the single crystal growth apparatus of the present invention according to the preceding item (0021) can monitor the crystal growth from the crucible wall surface with the temperature measuring sensor during crystal growth.
If there is crystal growth from the crucible wall, a rapid signal change occurs with respect to the temperature sensor. This is a signal indicating that crystal growth has occurred from the surface of the silica glass. When this signal is detected, the temperature is instantaneously increased by 10 ° C. to a specified temperature, for example, 1450 ° C., and the pulling rate is low. To prevent a decrease in crystal diameter. Thereafter, after the crystal growth from the crucible wall surface is melted, a defect in diameter is not caused by the control depending on the crystal diameter control system.

The single crystal growth apparatus of the present invention according to the preceding item (0031) instantaneously raises the temperature set value by 10 ° C. with respect to a specified value, for example, 1450 ° C. set temperature, when crystal growth from the crucible wall surface is detected. At the same time, in order to suppress the reduction of the crystal diameter, the growth rate is maintained at a growth rate of 0 to 0.5 mm / min, and the growth crystal from the crucible wall is melted. It is a single crystal growth apparatus that can be automatically adjusted to continue.
This is because the work proceeds for the purpose of eliminating a minus minus defect with respect to a rapid temperature rise.

  In addition, the single crystal growth apparatus of the present invention according to the preceding item (0026) determines a high temperature part and a low temperature part where the temperature is high from the measured temperature distribution in the circumferential direction of the crucible, modulates the crucible rotation, The portion where there is crystal growth is adjusted so that the high temperature portion passes slowly. Crystal growth from the crucible wall is dissolved by passing a high temperature region for a long time (slowly) and a low temperature region for a short time (faster) by applying a modulation signal to the crucible rotation and passing through the crystal part. The crystal growth state can be restored.

Furthermore, the single crystal manufacturing method of the present invention according to the preceding item (0009) can measure the temperature distribution without moving the position of the temperature measurement sensor by arranging the temperature measurement sensors in a straight line.
By using the line sensor type temperature sensor, it is not necessary to move the position of the temperature sensor, and the position moving mechanism can be simplified and the control program can be simplified.

Further, the single crystal growth apparatus of the present invention according to the preceding item (0021) uses temperature sensors arranged on a straight line, and measures the temperature distribution without moving the position of the temperature sensor.
In the case of a temperature sensor that measures one point, the area on the line can be monitored by moving the X table, but if a temperature sensor arranged on a straight line is used, a position moving operation becomes unnecessary.

  Furthermore, in the single crystal growth apparatus of the present invention according to the preceding item (0021), the temperature measurement sensors are arranged in a matrix, and thereby the temperature distribution can be measured without moving the position of the temperature measurement sensor. it can. In the case of a temperature sensor that measures an area, the area area can be monitored by moving the XY table. However, if temperature sensors arranged in a matrix are used, the temperature distribution of the area can be measured without moving the position. Become.

  The present invention can suppress the crystal growth from the crucible wall by measuring the boundary temperature between the crucible and the melt, and occurs when growing a large crystal having a half or more of the inner diameter of the crucible. Even if crystal growth from a certain crucible wall occurs, the growth can be detected at an early stage.

  In addition, crystal growth from the crucible wall can be eliminated, and large crystals can be grown safely and again, and when a large crystal is grown on the crucible by detecting and controlling the melt level by moving the sensor, In particular, since the change in the melt level also becomes large, there is an advantage that accurate melt level control can be performed. According to the invention, it is possible to prevent a large crystal from being dropped and to grow a large crystal in a small furnace.

FIG. 1 is an explanatory view showing a sensor for measuring the boundary between the crucible wall and the melt and control of crystal growth based on the measurement result. (Example 1) FIG. 2 is an explanatory diagram showing a signal obtained by observing a sensor output signal capturing crystal growth from the crucible wall with an oscilloscope. (Example 2) FIG. 3 is an example of the aiming position and temperature data when aiming the temperature sensor near the boundary between the crucible wall and the melt.

  The interface between the crucible wall and the melt is positioned at the center of the aim of the temperature sensor through the observation window of the crystal growth furnace. By selecting and installing a location where the optical path is not blocked by the furnace structure, it is possible to monitor the crystal growth from the crucible wall. This can be detected as soon as possible.

  Thereby, it is possible to prevent the growing crystal and the crystal growth from the crucible wall from contacting and solidifying. After detecting the crystal growth from the crucible wall, the crystal growth from the crucible wall can be dissolved by increasing the set temperature by 10 ° C. when the set temperature is 1450 ° C., for example. A rapid temperature rise prevents the diameter of the growing crystal from becoming thin and the aperture from becoming smaller, so the growth rate is maintained at a low rate growth rate of 0 to 0.5 mm / min. After melting, the temperature can be lowered to 80% of the temperature setting previously raised by the specified temperature, and the growth rate can be gradually increased to continue crystal growth of the same diameter as the straight body portion that has been grown up to that point. This is a crystal growth method.

For example, since the set temperature was raised by 10 ° C. when the set temperature was 1450 ° C., the crystal growth may be continued when the crystal is melted and lowered to 8 ° C. and returned to the original diameter again.
By installing the temperature sensor, the growth of large crystals can be facilitated. An object of the present invention is to provide the temperature sensor and realize the growth of large crystals without increasing the diameter of the crucible.

  FIG. 1 is a schematic diagram of an embodiment of the apparatus of the present invention, where 1 is a temperature sensor, 2 is a conversion unit that converts the amount of light obtained from the temperature sensor into an electrical signal, and 4 is a crystal growth control unit. . Reference numeral 11 denotes an observation window of the crystal growth furnace, and through this observation window, the aim of the sensor 1 captures the boundary portion of the quartz crucible inner surface 8 and the inner portion of the melt 13 so that the crystal growth of 7 is performed. This is a temperature detection mechanism that captures the temperature change at the nine boundary sites during the break.

Further, the light quantity captured by the optical system sensor unit of the temperature sensor 1 is guided to the converter 2 by an optical fiber, and reaches the display device via the converter 2 that converts the light quantity into an electrical signal corresponding to the temperature. The indicator 3 can display the actual temperature calibrated in the black body furnace, and can set the emissivity of the luminous body. From the converter 2, a current output of 0 to 20 mA and a voltage output of 0 to 1 V or 0 to 5 V can be obtained by connecting a resistor to the output terminal.
The heater power supply 5 has a function of adjusting the output power to 0 to the maximum power with the voltage signal 0 to 5 V using an AC power supply by a power control device. By connecting an adjustment signal to the input signal to this power control device, the power applied to the furnace heater 10 can be adjusted. The temperature control mechanism of the furnace can be performed by the power control device. The temperature inside the furnace can be kept constant by a furnace temperature sensor provided separately.

  In the growth of the single crystal 7, the tip of the seed crystal can be immersed in the melting by an elevating mechanism that lowers the seed chuck 6 in which the seed crystal (seed) is attached to the melt 13 in which the polycrystalline raw material is dissolved. The in-furnace temperature control mechanism can be adjusted to a set temperature at which the seed crystal does not melt and does not enter a supercooled state in which the seed crystal rapidly grows. The seed crystal can be pulled up while gradually rotating the seed chuck 6 upward after the temperature of the melt 13 is adjusted to the set temperature.

  In the growth process of the seed crystal, the transition defects in the seed crystal are eliminated by pulling up while adjusting the diameter of the seed crystal to about 10 to 3 mm and adjusting the growth rate to a growth rate of 0.5 to 5 mm / min. Can be metastasized. In a single crystal, a ridgeline appears depending on the axial orientation. For example, in a crystal having an axial orientation <111>, three ridge lines appear every 120 degrees in the circumferential direction. In the axial orientation <100> crystal, four ridge lines appear every 90 degrees in the circumferential direction. The ridgeline of the non-transitioned crystal rises, and it can be seen that the single crystal has become non-transitional due to its shape change.

  If no transition is confirmed, the pulling speed of the seed crystal is reduced, the diameter of the single crystal increases, and a growth process is gradually performed until the target product diameter is reached. The diameter of the single crystal 7 having a diameter maintaining the target diameter is controlled by increasing the ascent speed of 6. At the same time, appropriate temperature control can be performed on the diameter according to the temperature programmed by the power control mechanism. As the single crystal 7 grows, the melt 13 decreases depending on the single crystal diameter and the inner diameter ratio of the crucible that holds the melt. By compensating for the decrease in the melt 13 by the rise of the crucible shaft 12 at the same time, Thirteen levels can be kept in a fixed position. Since the crucible shaft 12 normally rotates in the reverse direction with the seed chuck 6 and moves up and down as it moves, vacuum sealing at the bottom of the furnace is performed using a magnetic fluid seal and a welding bellows.

FIG. 2 is a sensor signal that captures crystal growth from the crucible wall that is detected in synchronization with the rotation of the crucible by a temperature measurement sensor that is aimed at the boundary between the crucible wall and the melt in the furnace of the single crystal growth furnace. Here, it is an example in which a sawtooth wave that has detected a crystal grown from a crucible wall when the crucible rotates three times is captured by an oscilloscope.
The aim is equipped with a viewer that visually confirms the observation area, and it is structured so that it can be clearly seen as a concentric quadruple ring in it.

  After detecting the crystal grown from the crucible wall, the crystal growth from the crucible was stopped by raising the temperature of the set point of the furnace showing 1450 ° C., for example, 10 ° C., and the crystal was dissolved over time. Meanwhile, the crystal growth rate was suppressed to a growth rate of 0.01 to 0.5 mm / min to suppress a decrease in crystal diameter.

As the temperature sensor, a fiber type radiation thermometer FTK-A700A-50L11) of Japan Sensor Co., Ltd. and a parameter setting device PWC1 were used.
Since the sensor beam diameter at the time of this just focus is φ1.7 mm and the focal length is 500 mm, it is important to adjust the sensor objective distance to 500 mm. Moreover, although the measurement temperature range is 700-2000 ° C., the temperature display is a relative value because the observation window in the furnace is passed through a shading filter that can directly observe crystal growth with the naked eye. It doesn't matter.

FIG. 3 shows the temperature sensor value in the vicinity of the boundary between the crucible wall and the melt during single crystal growth, and the positional relationship and temperature of a quadruple circle indicating the aim.
The sights are 0.1 mm, 0.2 mm, 0.4 mm, and 0.6 mm in order from the inside of the circle.
Whether the focal length is in focus is determined by whether this circle is clearly visible. Therefore, the sensor can adjust the distance to match the boundary position with the focal position.

As can be seen from FIG. 3, the temperature becomes higher as the center of the aim of the boundary approaches, and the temperature output peaks when the center of the aim reaches the boundary.
By using this change and controlling the position of the crucible to the position where the boundary is always at the center of the aim, the position of the melt surface can be controlled more accurately than conventional liquid level detection by laser reflection. The system of single crystal diameter control by camera can also be improved.

The inner diameter of the crucible used in the experiment of the present invention was 165 mm, and a crystal having a maximum inner diameter of 132 mm, that is, 80% of the diameter, was grown from a small inner diameter crucible. During the experiment, there was crystal growth from the crucible wall, and the crystal was dissolved and extinguished by heating, followed by single crystal growth and single crystal growth up to the bottom of the crystal.
In the experiment, there was crystal growth from a crucible wall having a width of about 60 mm and a width of about 15 mm in the circumferential direction of the crucible, but the crystal could be dissolved at a temperature increase of 10 ° C. with respect to the set temperature of 1450 ° C. Although the predetermined temperature varies depending on the crucible diameter, large crystals can be grown by the same temperature rise and fall.
Conventionally, a crystal having a diameter of about one third of the inner diameter of the crucible was generally grown, but a crystal having a diameter more than twice that was able to be grown.

  The temperature sensor was allowed to move freely on the X axis, which is a horizontal axis, and the temperature distribution on the line was measured. By this operation, the temperature distribution on the straight line could be measured, and the crystal growth from the crucible wall in the region could be monitored. Furthermore, using an XY table that freely moves about the Y axis, which is the vertical axis, the crystal growth from the crucible wall in the horizontal and vertical regions could be grasped more accurately.

When the state of crystal growth from the crucible wall was changed for each of the crucible rotation and the seed rotation, it was found that the growth rate was faster as the rotation speed was lower and the growth rate was slower as the rotation speed was higher. It has been found that crystal growth from the crucible wall can be easily suppressed when the seed crystal rotation speed is 10 ± 0.5 rpm and the crucible rotation is 8 ± 2 rpm in the range of rotation with little rotational vibration.
In addition, there are a low temperature portion where crystal growth from the crucible wall is fast and a slow high temperature portion when the crucible rotates, and the growth can be suppressed by passing the low temperature portion quickly and slowly passing the high temperature portion.

  Crystal growth from the crucible wall was observed using a normal silica glass crucible and a liquid-filled liquid crucible. As the temperature decreases in the direction, the crucible cannot normally stop crystal growth from the crucible wall, and it has a tail, while the liquid crucible melts and extinguishes the crystal growth from the crucible wall once generated. I was able to. Moreover, the single crystal growth could be performed without falling below the target diameter by setting the single crystal growth rate at this time to 0 to 0.5 mm / min.

  The present invention can be applied to single crystal materials for semiconductor silicon wafers, silicon parts using silicon single crystals, and wafers for solar cells.

DESCRIPTION OF SYMBOLS 1 Temperature sensor 2 Converter 3 Display 4 Control part 5 Heater power supply 6 Seed chuck 7 Single crystal 8 Silica glass crucible 9 Boundary line 10 Heating heater 11 Observation window 12 Crucible shaft 13 Melt

Claims (24)

In a method for growing a single crystal using a single crystal growth furnace,
The temperature of the boundary between the crucible wall and the melt in the furnace is measured by the temperature measuring sensor, wherein the crucible wall to control the set temperature and growth rate of the single crystal of the melt during crystal growth based on the measurement result When crystal growth from the crucible wall is detected, the crystal growth from the crucible wall is suppressed by increasing the temperature, or the crystal nucleus grown from the crucible wall is dissolved . A single crystal growth method characterized in that a large crystal having an inner diameter of 80% or more of the inner diameter of the crucible is manufactured.   2. The single crystal growth method according to claim 1, wherein the temperature measurement sensor is slid in a direction perpendicular to the melt surface to check a melt surface level.   2. The single crystal growth method according to claim 1, wherein the temperature distribution in the circumferential direction of the crucible is measured at a portion where the temperature measurement sensor slides in the vertical and horizontal directions and the melt and the crucible contact each other.   4. The single crystal growth furnace according to claim 3, wherein the single crystal growth furnace is provided with a plurality of measurement windows, and each measurement window is provided with a temperature measurement sensor, and each temperature sensor is independently slid in the vertical direction and the horizontal direction to melt. A single crystal growth method characterized by measuring a temperature distribution in a circumferential direction of a crucible while tracking a portion where a liquid and a crucible contact.   3. A method for growing a single crystal, wherein the melt surface level grasped in claim 2 is always maintained and controlled at a predetermined level. 3. The single crystal growth method according to claim 2, wherein the temperature measuring sensor is slid in a direction parallel to the melt surface and the diameter of the crystal is measured.   7. The single crystal growth method according to claim 6, wherein the temperature measurement sensor is moved so that the distance from the melt surface of the temperature measurement sensor is always on the focal length.   The single crystal growth method according to any one of claims 1 to 7, wherein the crucible uses a silica glass crucible having a liquid-cooling property.   In any one of Claims 1-8, when the crystal growth from the crucible wall surface is detected, the growth rate is set to 0 to 0 in order to instantaneously raise the temperature setting value to the specified temperature and suppress the reduction of the crystal diameter. After maintaining the growth rate of .5 mm / min and dissolving the growth crystal from the crucible wall, the temperature is lowered to 80% of the temperature setting where the specified temperature has been raised first, and the growth rate is gradually increased to grow the crystal with the specified diameter. A single crystal growth method characterized by continuing.   The high temperature part and the low low temperature part are determined from the temperature distribution in the circumferential direction of the crucible measured in claim 4, the crucible rotation is modulated, and the part where crystal growth from the crucible passes slowly through the high temperature part. A method for growing a single crystal, characterized by comprising:   11. The single crystal growth method according to claim 1, wherein the seed crystal rotation speed is 10 ± 0.5 rpm and the crucible rotation is 8 ± 2 rpm. It has a temperature measurement sensor that measures the temperature at the boundary between the crucible wall and the melt in the single crystal growth furnace,
Maintaining the temperature not set temperature of the melt at the time of measurement the crystal growth based on the measuring sensor and the crystal nuclei in the crucible wall growth rate control to single crystal occurs a temperature, crystals from the crucible wall When growth is detected, crystal growth from the crucible wall is suppressed by heating, or large crystals having a diameter of 80% or more of the inner diameter of the crucible are manufactured by melting the nucleus of the crystal grown from the crucible wall. A single crystal growth apparatus characterized by that.   13. The single crystal growth apparatus according to claim 12, wherein the temperature measurement sensor is provided so as to be slidable in a direction perpendicular to the melt surface, thereby confirming a melt surface level.   13. The temperature measurement sensor according to claim 12, wherein the temperature measurement sensor is provided so as to be slidable in a vertical direction and a horizontal direction. A single crystal growth device.   15. A plurality of measurement windows are provided according to claim 14, and the temperature measurement sensor is provided in each measurement window so as to be slidable in the vertical and horizontal directions, whereby the melt and the crucible come into contact with each other. A single crystal growth apparatus characterized by measuring a temperature distribution in a circumferential direction of a crucible for a portion.   The single crystal growth apparatus characterized in that the melt surface level grasped in claim 13 is always maintained and controlled at a predetermined level.   14. The single crystal growth apparatus according to claim 13, wherein the temperature measurement sensor is provided so as to be slidable in a direction parallel to the melt surface, thereby measuring the diameter of the crystal.   The single crystal growth apparatus according to claim 17, further comprising a moving mechanism for always setting a distance from the melt surface of the temperature measurement sensor to a focal length.   The single crystal growth apparatus according to any one of claims 12 to 18, wherein the crucible is a silica glass crucible having a liquid crystallinity.   20. The growth rate of 0 to 0.5 mm / min according to any one of claims 12 to 19 in order to increase the temperature set value instantaneously and simultaneously suppress a reduction in crystal diameter when crystal growth from the crucible wall surface is detected. The single crystal growth apparatus is characterized in that the growth crystal from the crucible wall is melted and adjusted so as to continue the crystal growth by gradually increasing the growth rate after the dissolution is completed.   In claim 15, a high temperature portion and a low low temperature portion are determined from the measured temperature distribution in the circumferential direction of the crucible, the crucible rotation is modulated, and the portion where there is crystal growth from the crucible slowly moves the high temperature portion. A single crystal growth apparatus characterized by adjusting so as to pass through.   The single crystal growth method according to claim 1, wherein the temperature distribution is measured without moving the position of the temperature measurement sensor by arranging the temperature measurement sensors linearly.   13. The single crystal growth apparatus according to claim 12, wherein the temperature measurement sensors are arranged in a straight line, thereby measuring a temperature distribution without moving the position of the temperature measurement sensor.   The single crystal growth apparatus according to claim 12, wherein the temperature measurement sensors are arranged in a matrix and thereby measure a temperature distribution without moving the position of the temperature measurement sensor.

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