JP6395302B2 - Single crystal silicon pulling apparatus and single crystal silicon pulling method - Google Patents

Description

  The present invention relates to a single crystal silicon pulling apparatus and a single crystal silicon pulling method, and more particularly to controlling pulling temperature of single crystal silicon.

Single crystal silicon used for a semiconductor substrate or the like is generally manufactured by the Czochralski method (hereinafter referred to as CZ method).
In the CZ method, polycrystalline silicon (raw material silicon) is placed in a quartz crucible placed in a high pressure-tight airtight chamber, and the polycrystalline silicon is heated by heating a heater placed so as to surround the quartz crucible. Melt to form a silicon melt. A seed (seed crystal) is attached to a seed chuck disposed above the quartz crucible, and the seed is immersed in a silicon melt in the quartz crucible, and the seed is pulled up while rotating the seed and the quartz crucible, and the single crystal is Silicon is grown (for example, see Patent Document 1). In pulling up the single crystal silicon, the heater is controlled along a temperature control line that associates the length of the single crystal silicon to be pulled up (the pulling length) with the temperature of the quartz crucible.

  In the production of single crystal silicon by such a CZ method, it is important to maintain a dislocation-free state during pulling of the single crystal silicon. However, for example, in order to melt a large amount of raw silicon, the temperature of the wall of the quartz crucible rises, and the natural convection of the silicon melt increases, so that the melting of the quartz crucible proceeds and small particles of insoluble matter (cristobalite) By adhering to the growth interface, the single crystal silicon being pulled may be dislocated. When the single crystal silicon being pulled becomes dislocations, the pulling is stopped at that time, and the single crystal silicon that has already been pulled is taken out.

  When such dislocations occur at a position significantly shorter than the planned pulling length of single crystal silicon, a large amount of silicon melt remains in the quartz crucible. It is very troublesome to recover the remaining silicon melt by cooling, solidifying it, and using it again as a silicon raw material, and there is a concern of contamination by impurities. For this reason, using the silicon melt remaining in the quartz crucible, another single crystal silicon having a length shorter than the planned pulling length is pulled up.

Conventionally, when pulling single crystal silicon shorter than the originally planned pulling length from the silicon melt remaining in such a quartz crucible, the temperature control line corresponding to the initially planned pulling length is shorter than that. In order to obtain a temperature control line corresponding to the pulling length, an operator inputs parameters according to the remaining amount of silicon melt remaining in the quartz crucible and manually sets a temperature control line corresponding to the short pulling length. It was made by work.

JP 2001-278696A

  However, every time the single crystal silicon being pulled is dislocated, it is necessary to manually produce a temperature control line corresponding to a short pulling length each time depending on the amount of silicon melt remaining in the quartz crucible. It took a lot of time and hindered the efficient pulling of single crystal silicon.

  The present invention has been made in view of the above-described circumstances, and when single crystal silicon is dislocated, when another single crystal silicon is pulled according to the remaining amount of silicon melt remaining in the quartz crucible. It is an object of the present invention to provide a single crystal silicon pulling apparatus and a single crystal silicon pulling method that can easily generate a single temperature control line and efficiently manufacture single crystal silicon.

In order to solve the above-described problems, a single crystal silicon pulling apparatus according to the present invention includes a quartz crucible, a crucible driving means for rotating the quartz crucible around an axis, a heater for heating the quartz crucible, and the crucible driving. A single crystal silicon pulling apparatus comprising at least a means and a control unit for controlling the heater,
The heater is controlled along a first temperature control line indicating a relationship between the crucible temperature and the pulling length of the single crystal silicon, and the first temperature control line forms a shoulder portion of the single crystal silicon. And a straight body part temperature control line for forming a straight body part following the shoulder part, and the control part is shorter than the pulling length set in advance by the single crystal silicon When a dislocation is performed at a position, an unexecuted temperature control line after the position on the straight body temperature control line corresponding to the displaced position is connected to an end point of the front-stage temperature control line, A second temperature control line is generated.

According to such a single crystal silicon pulling apparatus of the present invention, when the single crystal silicon is dislocated during the pulling, the control unit performs an unexecuted temperature control line after the dislocation position of the single crystal silicon. Is connected to the front-stage temperature control line, and the second temperature control line is generated by the program, thereby eliminating the input error and calculation error due to manual calculation and facilitating the temperature control of the quartz crucible during re-drawing. Enable.
Note that the second temperature control line is a temperature control line that is generated according to the remaining amount of silicon melt when single crystal silicon undergoes dislocation relative to the temperature control line applied during the pulling operation. The second temperature control line is generated each time the dislocation is performed twice or more.

According to the present invention, the pull-up length corresponding to the front-end control line from the start point to the end point approximates a length corresponding to the diameter of the single crystal silicon.
Thereby, the setting of the front-stage control line can be facilitated.

According to the present invention, the second temperature control line is connected to an end point of the front stage temperature control line while maintaining an inclination of the unexecuted temperature control line.
Accordingly, it is possible to easily generate the second temperature control line in which only the pulling length is shortened in response to the state in which the amount of the silicon melt is reduced.

According to the present invention, the rotation speed of the quartz crucible is controlled along a first rotation speed control line indicating the relationship between the rotation speed of the quartz crucible and the pulling length of the single crystal silicon, The rotational speed control line includes a front stage rotational speed control line for forming a shoulder portion of single crystal silicon, and a straight body rotational speed control line for forming a straight body portion following the shoulder portion, When the single crystal silicon is dislocated at a position shorter than a preset pull-up length, the control unit is not executed after the position on the straight body rotation speed control line corresponding to the position at which the single crystal silicon is shifted. The second rotational speed control line is generated by connecting the rotational speed control line to the end point of the preceding stage rotational speed control line.
As a result, when the crystalline silicon undergoes dislocation in the middle of pulling, the control unit connects the unexecuted rotational speed control line after the dislocation position of the single crystal silicon to the preceding stage rotational speed control line. By automatically generating the second rotation speed control line by a program, it becomes possible to eliminate the input error and calculation error due to manual calculation and facilitate the rotation speed control of the quartz crucible in the re-pulling.

According to the present invention, when the unexecuted rotational speed control line is connected to the end point of the preceding stage rotational speed control line, the starting point of the unexecuted rotational speed control line and the preceding stage rotational speed control line When there is a difference in the set rotation speed from the end point, the connection between the start point of the unexecuted rotation speed control line and the end point of the front-stage rotation speed control line is made via an inclined adjustment straight line. It is characterized by doing.
As a result, when the second rotational speed control line is generated, even if there is a difference in the set rotational speed between the start point of the unexecuted rotational speed control line and the end point of the preceding stage rotational speed control line, it is abrupt. A second rotation speed control line that does not cause fluctuations in the rotation speed can be obtained.

The single crystal silicon pulling method of the present invention is a single crystal silicon pulling method using the single crystal silicon pulling apparatus described in the above items,
Introducing a predetermined amount of silicon raw material into the quartz crucible; heating the heater along the first temperature control line; and pulling single crystal silicon from a silicon melt obtained by melting the silicon raw material; When the single crystal silicon is dislocated at a position shorter than a preset pull-up length, stopping the pulling of the single crystal silicon and forming the second temperature control line; and A step of heating the heater along a temperature control line and pulling another single crystal silicon from the silicon melt remaining in the quartz crucible.

  According to the single crystal silicon pulling method of the present invention, when single crystal silicon is dislocated during pulling, an unexecuted temperature control line after the dislocation position of single crystal silicon is changed to a front-stage temperature control line. By connecting and generating the second temperature control curve by the program, it becomes possible to eliminate the input error and calculation error due to manual calculation and facilitate the temperature control in the re-pull-up.

  According to the single crystal silicon pulling apparatus and single crystal silicon pulling method of the present invention, after the single crystal silicon is dislocated, another single crystal silicon is selected depending on the remaining amount of the silicon melt remaining in the quartz crucible. The temperature control line for pulling up can be easily generated, enabling efficient production of single crystal silicon.

It is sectional drawing which shows the single crystal silicon pulling-up apparatus of this invention. It is a flowchart which shows an example of the single crystal silicon pulling-up method of this invention. It is explanatory drawing which shows the pulling-up length of single crystal silicon, and a temperature control line. It is explanatory drawing which shows the pulling-up length of single crystal silicon, and a temperature control line. It is explanatory drawing which shows the pulling length of single crystal silicon, and a rotation speed control line. It is explanatory drawing which shows the pulling length of single crystal silicon, and a rotation speed control line.

  Hereinafter, a single crystal silicon pulling apparatus and a single crystal silicon pulling method of the present invention will be described with reference to the drawings. Each embodiment described below is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, there is a case where a main part is shown in an enlarged manner for convenience, and the dimensional ratio of each component is the same as the actual one. Not necessarily.

The structure of the single crystal silicon pulling apparatus of the present invention will be described.
FIG. 1 is a schematic view showing an example of a single crystal silicon pulling apparatus.
The single crystal silicon manufacturing apparatus 1 includes a pressure-tight and air-tight chamber 10, a quartz crucible 15, a seed chuck 17, a heater 19, a crucible support 21, and a seed chuck driving mechanism 30, and a reduced pressure state. The single crystal silicon T is grown by immersing the seed S attached to the seed chuck 17 in the silicon melt M stored in the quartz crucible 15 and pulling it up while rotating. .

  The chamber 10 includes a main chamber 11, a top chamber 12 connected to the top of the main chamber 11, and a pull chamber 13 connected to the top of the top chamber 12. The main chamber 11 is erected on the bottom 11A and the bottom 11A. A quartz crucible 15 is disposed at the center, and a vacuum pump (not shown) is connected to the exhaust hole 11D so that the chamber 10 can be depressurized or evacuated. .

  Further, when the spill tray 14 is disposed at the bottom 11A of the main chamber 11, and the quartz crucible 15 is broken and the silicon melt M flows out, the silicon melt M directly contacts the bottom 11A. Thus, the chamber can be prevented from being damaged.

  The pull chamber 13 is formed in a substantially cylindrical shape, has a space for storing the pulled single crystal silicon T, and is connected to the main chamber 11 by the top chamber 12. A shutter (not shown) that thermally isolates the pull chamber 13 from the main chamber 11 and the top chamber 12 is formed between the pull chamber 13 and the top chamber 12. Even when the silicon melt M is stored in the quartz crucible 15 by such a shutter, the single crystal silicon T in a state where only a part of the initial plan is pulled out from the pull chamber 13 can be taken out. It has become.

  The quartz crucible 15 is capable of holding massive polycrystalline silicon (raw material silicon), which is a raw material of the single crystal silicon T, in the concave portion of the quartz crucible 15 and is formed by heating and melting the polycrystalline silicon. M can be stored and is stored in the graphite crucible 16. For example, the temperature of the silicon melt M can be maintained at a desired temperature by controlling the temperature of the quartz crucible 15.

  The graphite crucible 16 is integrally formed by being held by a pedestal 21 </ b> C disposed on the upper surface of the crucible support base 21, and the support part 21 </ b> A has a support part 21 </ b> A at the center of the bottom part 11 </ b> A of the main chamber 11. And inserted into a through hole 11H formed through the bottom portion 11A and the spill tray 14, and can be rotated and moved up and down relatively with respect to the main chamber 11.

A cylindrical heater 19 is disposed around the graphite crucible 16, a cylindrical heat retaining cylinder 22 is disposed outside the heater 19, and a radiation thermometer 40 is disposed outside the heat retaining cylinder 22.
The heat insulating tube 22 has an inner heat insulating tube 22A made of cylindrical graphite and an outer heat insulating tube 22B made of cylindrical porous graphite disposed outside the inner heat insulating tube 22A, and has an inner diameter of the inner heat insulating tube 22A. A disc-shaped upper ring 22D having a hole with a diameter substantially the same as the inner diameter of the inner heat retaining cylinder 22A is disposed above the disk-shaped lower ring 22C having a hole with a diameter substantially the same as that of the inner heat retaining cylinder 22A. Has been.

  The lower portion of the heater 19 is fixed to the electrode joint 19A with bolts 19B, and the electrode joint 19A is connected to the power supply device P1 through a graphite electrode 19C disposed in a through hole formed in the spill tray 14. For example, the electric power supplied from the power supply device P1 is controlled in the heater 19 so that the temperature of the silicon melt M is maintained at a predetermined temperature.

  The radiation thermometer 40 is for measuring the temperature of the heat insulating cylinder 22. In the present embodiment, the electric power of the heater 19 is adjusted based on the measurement data of the radiation thermometer 40 to control the temperature of the silicon melt M. The temperature measured by the radiation thermometer 40 is substantially the same as the temperature of the quartz crucible 15.

The electric power of the heater 19 is controlled so that the temperature measured by the radiation thermometer 40 becomes preset temperature data.
The temperature data includes a growth amount of the single crystal silicon T (a growth length from the liquid surface of the silicon melt M) and a temperature gradient set according to the growth amount of the single crystal silicon. In the present embodiment, this growth amount is associated with the pulling length of single crystal silicon. Details of the temperature data will be described later.

A flow pipe 25 is attached to the upper end of the heat insulating cylinder 22 via an upper ring 22 </ b> D and an adapter 23.
The flow tube 25 is an inverted frustoconical hollow cylinder whose upper end opening is larger in diameter than the lower end opening, and is made of graphite or SiC.
The seed chuck 17 is connected to the wire W at the proximal end side, and the seed S is rotatable and raised relative to the main chamber 11 by connecting the wire W to the seed chuck drive mechanism 30.

  The seed chuck drive mechanism 30 is provided in the upper part of the pull chamber 13, and can be rotated relative to the pull chamber 13 with the pulley 31 connected to the proximal end of the wire W and wound, and the wire W as the rotation axis O. A rotation drive unit 32, and the pulley 31 winds up the wire W so that the seed chuck 17 moves up and down, and the rotation drive unit 32 rotates so that the seed chuck 17 turns around the wire W. It has become.

  Further, the single crystal silicon manufacturing apparatus 1 includes a control unit 50. The controller 50 is configured to be able to control the rotation of the crucible support base 21 and the rotation and elevation of the seed chuck drive mechanism 30, and the rotational direction and rotational speed of the crucible support base 21 and the rotational drive in the seed chuck drive mechanism 30. The rotational direction and rotational speed of the seed chuck 17 by the part 32 and the raising and lowering and pulling (lifting) speed of the seed chuck 17 by the pulley 31 can be controlled.

  The control unit 50 includes, for example, a first inverter 51, a second inverter 52, a third inverter 53, a fourth inverter 55, and a calculation unit 54. The inverter 52, the third inverter 53, and the fourth inverter 55 are configured to send a drive signal based on an instruction signal from the calculation unit 54.

The control unit 50 can control the rotation direction and rotation speed of the quartz crucible by changing the frequency of the first inverter 51 and controlling the rotation direction and rotation speed of the motor M1 that rotates the crucible support base 21, for example. The rotational speed of the crucible support 21 can be adjusted from 1.0 rpm to 30 rpm, for example.
The first inverter 51 and the motor M1 constitute a crucible rotation control means. Such rotation control of the quartz crucible 15 by the motor M1 will be described in detail later.

Further, the control unit 50 changes the frequency of the second inverter 52 to control the rotation direction and the number of rotations of the motor M2 that rotates the rotation drive unit 32 of the seed chuck drive mechanism 30, thereby rotating the seed chuck 17. The rotation direction (right rotation, left rotation) and the rotation speed around the axis O can be adjusted, and the rotation speed of the seed chuck 17 can be adjusted from 0.5 rpm to 15 rpm.
The second inverter 52 and the motor M2 constitute seed rotation control means.

Further, the control unit 50 changes the frequency of the third inverter 53 and controls the rotation direction and the rotation speed of the motor M3 that rotates the pulley 31 around which the wire W is wound, thereby moving the seed chuck 17 up and down. The pulling speed can be adjusted, and the pulling speed of the seed chuck 17 can be adjusted from 0.01 rpm to 10 rpm.
The third inverter 53 and the motor M3 constitute seed pulling speed control means.

The control unit 50, via the fourth inverter 55, the voltage and current output from the power supply device P1 control. Thereby, the power of the heater 19 can be controlled, and the temperature of the silicon melt M can be set to a predetermined temperature. The fourth inverter 55 is controlled based on the temperature of the heat retaining cylinder 22 detected by the radiation thermometer 40. The heater 19 is temperature controlled according to a temperature control curve input to the control unit 50. Such temperature control of the heater 19 will be described in detail later.

  Note that the fourth inverter 55 is configured to directly measure the temperature of the quartz crucible using, for example, a thermocouple, in addition to performing control based on the temperature of the heat retaining cylinder 22 detected by the radiation thermometer 40. There may be.

Next, the operation of the single crystal silicon manufacturing apparatus 1 having the above-described configuration and the single crystal silicon manufacturing method of the present invention will be described.
FIG. 2 is a flowchart showing stepwise the method for producing single crystal silicon according to the present invention. In the silicon single crystal manufacturing method of the present invention, for example, a single crystal silicon manufacturing apparatus 1 shown in FIG. 1 is used.
First, massive polycrystalline silicon (raw material silicon) as a raw material is filled in the quartz crucible 15 (raw material filling step S1). Then, the quartz crucible 15 is heated by the heater 19 to form a silicon melt M obtained by melting polycrystalline silicon, and the silicon melt M in the vicinity of the portion where the seed S is immersed is brought into a supercooled state ( Raw material melting step S2).

  Next, the seed S is inserted into the seed chuck 17 and fixed. Next, the seed chuck drive mechanism 30 is driven, the seed chuck 17 is lowered, the seed S is immersed in the silicon melt M, and the seed S is adapted to the silicon melt M (seed immersion step S3).

  When the seed S becomes familiar with the silicon melt M, the seed chuck 17 is raised while rotating. The seed S is for growing single crystal silicon from the silicon melt M. When the seed S comes into contact with the silicon melt M, the single crystal silicon T having the same atomic arrangement as the seed S is connected to the seed S. (First crystal growth step S4).

  The pulling (crystal growth) of the silicon single crystal T is performed by rotating the seed chuck 17 to rotate the silicon single crystal T itself, rotating the crucible support 21 to rotate the quartz crucible 15 storing the silicon melt M, and the seed. By controlling the pulling speed by raising the chuck 17 and the heating temperature of the quartz crucible 15 by the heater 19 (substantially approximate to the temperature of the silicon melt M), a silicon single crystal T having desired properties is grown. Can do.

  Among these, the heating temperature of the quartz crucible 15 is controlled by applying an arbitrary electric power to the heater 19 via the fourth inverter 55 by the control unit 50. The optimum heating temperature of the quartz crucible 15 always fluctuates due to a change in heat dissipation characteristics corresponding to the portion of the silicon single crystal to be pulled up and a change in the remaining amount of the silicon melt M. Therefore, the length of the silicon single crystal T to be pulled up along the pulling direction (hereinafter sometimes referred to as the pulling length) and the heating temperature of the heater 19 (hereinafter also referred to as the pulling temperature). The pulling temperature is controlled so as to follow the temperature control line indicating the relationship. Such temperature control lines are generally indicated by curves.

  FIG. 3A is an example of a temperature control curve Q (first temperature control line) showing the relationship between the pulling length of the silicon single crystal T and the pulling temperature. In the present invention, the control unit 50 controls the power value applied to the heater 19 along the temperature control curve Q to change the pulling temperature.

  The silicon single crystal T generally includes a shoulder portion Es that is expanded from a small diameter portion that is continuous with the seed S toward a target diameter, and a straight body portion Eb that is continuous with the shoulder portion Es and extends with a diameter in a predetermined range. And a substantially cylindrical shape composed of the end portion Et. In general, a neck portion (not shown) with a reduced diameter is formed between the seed S and the shoulder portion Es in order to cut off the inheritance of crystal defects.

  The temperature control curve (first temperature control line) Q1 includes a section Q1A of the front stage temperature control line for forming the shoulder portion Es of the single crystal silicon T and a straight body temperature control for forming the straight body portion. It consists of two sections, line section Q1B. When pulling up the shoulder portion Es of the silicon single crystal T, since there are many heat radiation portions due to the outer surface facing upward, the section Q1A of the front-stage temperature control line starts to be pulled from a relatively high temperature state. It has a linear shape that lowers the pulling temperature along with the diameter expansion. The pull-up length corresponding to the section Q1A of the front-stage temperature control line from the start point to the end point may be a value approximate to the length corresponding to the diameter of single crystal silicon, for example. On the other hand, the section Q1B of the straight body temperature control line between the straight body portion Eb and the terminal portion Et following the section Q1A of the front stage temperature control line has a linear shape in which the pulling temperature is gradually increased. Yes.

  While the heating temperature of the quartz crucible 15 is controlled so as to follow the temperature control curve Q1, when the single crystal silicon T grows without dislocation over the entire length up to the initially planned pulling length L, it is pulled up from the pull chamber 13. The obtained single crystal silicon T is taken out to obtain a single crystal silicon T having a pulling length L (S5).

  On the other hand, when the control unit 50 controls the pulling temperature along the temperature control curve Q1, if the single crystal silicon is dislocated, the pulling is stopped at that time, and the already pulled portion of the single crystal silicon is removed. Remove (S6). For example, as shown in FIG. 3B, of the initially planned pull-up length L of the single crystal silicon T, for example, when dislocation occurs in the middle of the straight body Eb, the pull-up is performed at this dislocation position Sp. To stop. Then, the silicon single crystal T1 having the pulling length L1 up to the dislocation position Sp is taken out and used for production of a silicon wafer or the like.

  On the other hand, in the quartz crucible 15, in the raw material melting step S 2, an amount of silicon melt M that can be pulled up from the originally planned single crystal silicon T having the pull-up length L is stored, so that the dislocation position Sp is reached. Even after the silicon single crystal T1 having the pulling length L1 is taken out, a considerable amount of the silicon melt M remains. From this remaining silicon melt M, a silicon single crystal having a pulling length shorter than the originally planned pulling length L is pulled up.

  The control unit 50 generates a new temperature control curve Q2 that matches the amount of the remaining silicon melt M. Specifically, as shown in FIG. 4A, the unexecuted temperature control line after the position Q1BP1 corresponding to the dislocation position Sp of the single crystal silicon T in the section Q1B of the straight body temperature control line. The second temperature control curve (second temperature control line) Q2 is generated by connecting the section Q1BX (refer to the dotted line in the figure) to the end point Q1AP1 of the section Q1A of the preceding stage temperature control line (second temperature control line) Temperature control line generation step S7).

  When the section Q1BX of the unexecuted temperature control line is connected to the end point Q1AP1 of the section Q1A of the pre-stage temperature control line, the connection is made while maintaining the slope on the graph of the section Q1BX of the unexecuted temperature control line. It is preferable to do.

As shown in FIG. 4B, using the second temperature control curve Q2 obtained in this way, while controlling the heating temperature of the quartz crucible 15 along the second temperature control curve Q2, The single crystal silicon T2 having a pulling length L2 is pulled up from the remaining silicon melt M (second crystal growth step S8).
).

  When the single crystal silicon undergoes dislocation in the middle of controlling the pulling temperature along the temperature control curve Q1 by the above process, the pulling length L1 of the single crystal silicon T1 and pulling Two single crystal silicons with the long L2 single crystal silicon T2 can be obtained (S9).

  Conventionally, the second temperature control curve corresponding to the remaining amount of the silicon melt M after the dislocation has been manually input. However, in the present invention, the position after the dislocation position of the single crystal silicon T has been input. By connecting the temperature control line corresponding to the unexecuted section Q1BX to the section Q1A of the pre-stage temperature control line and automatically generating the second temperature control curve Q2 by the program, input errors and calculation errors are eliminated. Thus, it is possible to facilitate the temperature control in the re-pulling.

  When the second temperature control curve Q2 is generated, the weight of the single crystal silicon T1 is between the end point of the section Q1A of the front-stage temperature control line and the start point of the section Q1BX of the unexecuted temperature control line. It is also preferable to calculate so as to correspond to the length when converted into a cylinder having a target diameter.

  Moreover, although each temperature control line mentioned above is made into the curve (temperature control curve), the structure which connected the some straight line may be sufficient and it is not limited to a curve. The linear shape of the temperature control line illustrated is an example, and is not limited to such a linear shape, and an arbitrary linear temperature control line can be used.

The second temperature control curve Q2, to the temperature control line which is applied during the pulling run of the single-crystal silicon, according to the remaining amount of the silicon melt M in the single-crystal silicon is dislocated The temperature control line is generated each time, and the second temperature control line can be generated each time for two or more dislocations.

  The rotation speed (rotation speed) of the quartz crucible 15 is controlled by the control unit 50 via the first inverter 51. The optimum rotational speed of the quartz crucible 15 always varies depending on the portion of the silicon single crystal to be pulled up. For this reason, the rotational speed of the quartz crucible 15 is controlled so as to follow a rotational speed control line indicating the relationship between the pulling length of the silicon single crystal T to be pulled up and the rotational speed of the quartz crucible 15.

  FIG. 5A is an example of a rotation speed control line R1 (first rotation speed control line) showing the relationship between the pulling length of the silicon single crystal T and the rotation speed of the quartz crucible. In the present invention, the control unit 50 controls the motor M1 that rotates the crucible support base 21 along such a rotation speed control line R1, and changes the rotation speed of the quartz crucible.

  The rotation speed control line R1 includes a section R1A of the front-stage rotation speed control line for forming the shoulder portion Es of the single crystal silicon T, and a section R1B of the straight body rotation speed control line for forming the straight body section. These two sections are provided at least. The section R1A of the front-stage rotational speed control line starts to be pulled up from a relatively high rotational speed state, and forms a linear shape that decreases the rotational speed as the silicon single crystal T expands. The pull-up length corresponding to the section R1A of the front-stage rotation speed control line from the start point to the end point may be a value approximate to the length corresponding to the diameter of single crystal silicon, for example. On the other hand, the section R1B of the straight body rotation speed control line between the straight body portion Eb and the terminal end Et following the section R1A of the front stage rotation speed control line has a linear shape in which the rotation speed is gradually increased. ing.

  When the single crystal silicon T grows without undergoing dislocation over the entire length up to the initially planned pulling length L while controlling the rotational speed of the quartz crucible 15 along the rotational speed control line R1, the pull chamber 13 The pulled single crystal silicon T is taken out to obtain a single crystal silicon T having a pulling length L.

  On the other hand, when the control unit 50 controls the rotation speed along the rotation speed control line R1, when the single crystal silicon is dislocated, the pulling is stopped at that time, and the already pulled portion of the single crystal silicon is removed. Take out. For example, as shown in FIG. 5B, of the initially planned pull-up length L of the single crystal silicon T, for example, when dislocation occurs in the middle of the straight body portion Eb, the single crystal silicon T is pulled up at this dislocation position Sp. To stop. Then, the silicon single crystal T1 having the pulling length L1 up to the dislocation position Sp is taken out and used for production of a silicon wafer or the like.

  On the other hand, in the quartz crucible 15, an amount of silicon melt M that can be pulled up from the originally planned single crystal silicon T having the pull-up length L is stored, so that the pull-up length L 1 up to the dislocation position Sp is increased. Even after the silicon single crystal T1 is taken out, a considerable amount of the silicon melt M remains. From this remaining silicon melt M, a silicon single crystal having a pulling length shorter than the originally planned pulling length L is pulled up.

The controller 50 generates a new rotation speed control line R2 that matches the amount of the remaining silicon melt M. Specifically, as shown in FIG. 6A, in the section R1B of the straight body rotation speed control line, the unexecuted rotation speeds after the start point R1BP1 corresponding to the dislocation position Sp of the single crystal silicon T The section R1BX of the control line (see the dotted line in the figure) is translated and connected to the end point R1AP1 of the section R1A of the front stage rotation speed control line.

At this time, when there is a difference in the set rotational speed between the start point R1 BP 1 of the section R1BX of the unexecuted rotational speed control line and the end point R1AP1 of the section R1A of the preceding stage rotational speed control line, the rotational speed Even if the section R1BX of the control line is translated on the graph, it cannot be connected to the end point R1AP1 of the section R1A of the front-stage rotation speed control line. In this case, the starting point R1BP1 of the section R1BX of the unexecuted rotation speed control line and the end point R1AP1 of the section R1A of the preceding stage rotation speed control line are connected via the inclined adjustment straight line RL. The inclination and length of the adjustment straight line RL may be appropriately set according to, for example, the remaining amount of the silicon melt M, the expected pull-up length of the single crystal silicon pulled up from the remaining silicon melt M, and the like. Good.

As shown in FIG. 6 (b), using a second rotational speed control line R2 obtained in this manner, the rotational speed of the quartz crucible 15 along the second rotational speed control line R2 While controlling, the single crystal silicon T2 having the pulling length L2 is pulled up from the remaining silicon melt M.

Through the above steps, in the middle of the control unit 50 along the rotational speed control line R1 controls the rotational speed of the quartz crucible 15, when the single crystal silicon T is dislocated, the single crystal pulling length L1 Two single crystal silicons, silicon T1 and single crystal silicon T2 having a pulling length L2, can be obtained.

  Conventionally, the second rotation speed control line corresponding to the remaining amount of the silicon melt M after dislocation has been manually input. However, in the present invention, after the dislocation position of the single crystal silicon T By connecting the section R1BX of the unexecuted rotation speed control line to the section R1A of the front-stage temperature control line via the adjustment straight line RL and automatically generating the second rotation speed control line R2 by a program, It is possible to eliminate the input error and the calculation error and facilitate the rotation speed of the quartz crucible 15 in the re-pulling.

Note that the second rotational speed control line R2 is the remaining amount of the silicon melt M when the single crystal silicon is dislocated relative to the rotational speed control line applied during the pulling of the single crystal silicon. Accordingly, the second rotation speed control line is generated each time, and the second rotation speed control line can be generated each time for two or more dislocations.

  As mentioned above, although the manufacturing apparatus of the single crystal silicon which concerns on one Embodiment of this invention was demonstrated, this invention is not limited to this, In the range which does not deviate from the technical idea of the invention, it can change suitably.

  The shape of the temperature control line and the rotational speed control line shown in the above embodiment is an example, and an appropriate shape of the temperature control line and the rotational speed control line is formed according to the shape and characteristics of the single crystal silicon to be pulled up. That's fine.

  In the above embodiment, when the single crystal silicon being pulled has undergone dislocation, an example in which a temperature control line and a rotation speed control line for continuously pulling another single crystal silicon are generated by a program has been shown. . However, other than this, it is more preferable to automatically generate a control line for controlling the pulling speed, the crystal rotation speed, the flow rate of the inert gas, the furnace pressure in the chamber, and the like by the same method. .

  In addition, the linearity of each rotational speed control line mentioned above is an example, and it is not limited to such a linear form, Arbitrary linear rotational speed control lines can be used.

M silicon melt S seed T single crystal silicon 1 single crystal silicon manufacturing apparatus 10 chamber 15 quartz crucible (crucible)
19 Heater

Claims (6)

A quartz crucible,
Crucible driving means for rotating the quartz crucible around an axis;
A heater for heating the quartz crucible;
A controller for controlling the crucible driving means and the heater, and a single crystal silicon pulling apparatus comprising at least
The heater is controlled along a first temperature control line indicating a relationship between the crucible temperature and the pulling length of the single crystal silicon,
The first temperature control line includes a front temperature control line for forming a shoulder portion of single crystal silicon, and a straight body temperature control line for forming a straight body portion following the shoulder portion,
When the single crystal silicon undergoes dislocation at a position shorter than a preset pull-up length, the control unit is not executed after the position on the straight body temperature control line corresponding to the position at which the single crystal silicon is formed. The temperature control line is connected to the end point of the preceding stage temperature control line to generate a second temperature control line.   The single crystal silicon pulling apparatus according to claim 1, wherein a pulling length corresponding to a point from a start point to an end point of the front stage temperature control line is approximate to a length corresponding to a diameter of the single crystal silicon. The said 2nd temperature control line maintains the inclination of the said unexecuted temperature control line, and is connected to the end point of the said front part temperature control line, The Claim 1 or 2 characterized by the above-mentioned. Single crystal silicon pulling device. The rotation speed of the quartz crucible is controlled along a first rotation speed control line indicating the relationship between the rotation speed of the quartz crucible and the pulling length of single crystal silicon,
The first rotational speed control line includes a front part rotational speed control line for forming a shoulder portion of single crystal silicon, and a straight body rotational speed control line for forming a straight body part following the shoulder part. With
When the single crystal silicon undergoes dislocation at a position shorter than a preset pull-up length, the control unit is not yet positioned after the position on the straight body rotation speed control line corresponding to the dislocated position. 4. The single crystal according to claim 1 , wherein a second rotational speed control line is generated by connecting an execution rotational speed control line to an end point of the preceding stage rotational speed control line. 5. Silicon pulling device.   When connecting the unexecuted rotation speed control line to the end point of the preceding stage rotation speed control line, between the start point of the unexecuted rotation speed control line and the end point of the preceding stage rotation speed control line. When there is a difference in the set rotational speed, the starting point of the unexecuted rotational speed control line and the end point of the preceding stage rotational speed control line are connected via an inclined adjustment straight line. The single crystal silicon pulling apparatus according to claim 4. A single crystal silicon pulling method using the single crystal silicon pulling apparatus according to any one of claims 1 to 5,
Introducing a predetermined amount of silicon raw material into the quartz crucible;
Heating the heater along the first temperature control line, and pulling single crystal silicon from a silicon melt obtained by melting the silicon raw material;
When the single crystal silicon is dislocated at a position shorter than a preset pull-up length, the step of stopping the pulling of the single crystal silicon and forming the second temperature control line;
A step of heating the heater along the second temperature control line and pulling another single crystal silicon from the silicon melt remaining in the quartz crucible in order. Pulling method.

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