JP2939601B2 - Single crystal manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates relates to apparatus for producing a single crystal by the CZ method.

[0002]

2. Description of the Related Art When a single crystal is pulled using the CZ method, a chamber is formed in accordance with each step of pulling a single crystal, ie, drawing, shoulder expansion, straight body formation, and tail formation, in order to increase the crystal yield and the crystal cooling rate. It is necessary to control the temperature of the heater electrodes and the like to an optimum state. Regarding this, the following lifting method and lifting device are known. (1) As shown in JP-A-62-197398, a single crystal is grown while giving a specific change in the temperature and flow rate of the cooling water for the seed shaft and the crucible shaft in accordance with the single crystal pulling process. A single crystal pulling method for obtaining a good quality single crystal at a high yield by maintaining the shape of the crystal growth interface uniform. (2) As shown in Japanese Utility Model Laid-Open Publication No. 1-94468, a cooling cylinder for cooling the single crystal in a state surrounding the single crystal is detachably provided vertically on the upper end surface of the chamber containing the crucible. A pulling device that gives an appropriate cooling effect according to the diameter of the crystal and maintains good quality of the single crystal.

[0003]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 62-19 / 1987
In the single crystal pulling method disclosed in Japanese Patent No. 7398, the cooling ability in the chamber is insufficient, so that the temperature controllability, especially the rising characteristic is poor, and the crystal shape cannot be sufficiently controlled.
The single crystal pulling apparatus disclosed in Japanese Utility Model Laid-Open No. 94468/1989 has an effect on crystal cooling, but is inferior in the temperature control speed and control accuracy in the chamber, which are indispensable for the crystal shape, and therefore improves the crystal yield. It is not possible. ______________________________________ The present invention pays attention to the above-mentioned conventional problems, and an object of the present invention is to provide a single crystal manufacturing apparatus capable of obtaining a single crystal of good quality and high shape accuracy at a high yield.

[0004]

In order to achieve the above object, a first invention according to the present invention is provided in a chamber.
This single crystal is converted from a semiconductor melt melted in a crucible.
Made of single crystal that pulls up the inert gas while flowing down around
Hollow tube surrounding the periphery of a pulled single crystal
An outer peripheral surface of the hollow tubular member
From heat sources such as the melt surface of the crucible and the inner wall of the crucible.
A concave curved surface that reflects the radiant heat of the
And having, tea exposed to radiant heat reflected by the curved surface
It has a configuration that has a water temperature adjusting device that adjusts the temperature of the cooling water that cools the upper part of the chamber . The second invention is the first
In the single crystal manufacturing apparatus according to one aspect of the invention , the water temperature adjusting device adjusts the temperature of the cooling water for each single crystal pulling step.

[0005]

According to the first aspect of the present invention , there are provided a crucible melt surface and a crucible.
The radiant heat radiated from the inner wall surface toward the pulled single crystal is
On the outer peripheral surface of the hollow tubular member surrounding the outer periphery of the pulled single crystal
Reflects on the concave curved surface and reaches the upper inner wall of the chamber
You. Therefore, first, the inert gas due to this radiant heat
And the temperature rise of the single crystal surface can be directly suppressed, is suppressed reduce the temperature rise of the single crystal surface because of this. That is , the single crystal can be cooled in a short time, and the cooling rate of the single crystal can be improved. Second, it receives radiant heat reflected by the concave curved surface.
The upper part of the chamber where the temperature rise is
Cooling with more conditioned cooling water
The convective heat of the inert gas generated by the collision was cooled,
As a result, high convection heat indirectly passes through the inert gas or single crystal surface.
No heating is required. That is, in the chamber
Temperature control accuracy and crystal shape and quality accuracy are high
And the yield of single crystals can be improved.

[0006] In the meantime, single crystal production involves a plurality of steps.
The temperature must be suitable for each process.
Is common. Further, according to the first aspect,
For example, as described above, the temperature inside the chamber is adjusted with high accuracy.
Lick That is, the “water temperature control device of the second invention
The temperature is adjusted for each single crystal pulling process. "
Utilize the first invention having the above-described functions and effects.
This makes it possible to quickly and
The temperature can be changed and maintained quickly (with good responsiveness). You
In other words, the second invention is the first invention only in its operation and effects.
And effect. Therefore, the temperature in the chamber can be controlled with high accuracy, and the quality and the shape accuracy are high.
A single crystal can be obtained with a high yield .

[0007]

FIG . 1 is a schematic explanatory view of an embodiment . Between the chamber 1 and the cooling water supply device 2 of the Si single crystal manufacturing device,
Temperature-controlled device 3 (hereinafter, referred to as in-line chiller 3) Ru provided. The cooling water supply device 2 includes a cooling water supply water pipe 2a,
The cooling water is connected to the in-line chiller 3 via a return water pipe 2b. In-line chiller 3 is 3a, 3b, 3c,
3d, divided into four sections, between the inline chiller 3a and a load cell and a seed shaft (not shown), between the inline chiller 3b and the top chamber 1a, between the inline chiller 3c and the main chamber 1b, and between the inline chiller 3d and the heater. Between the electrode 4 and the crucible shaft 5,
Cooling water supply water pipes 31, 33, 35, 37 and cooling water return water pipes 32, 34, 36, 38 are provided, respectively. The water temperature of the cooling water return water pipes 32, 34, 36, 38 is
The temperature is detected by a temperature sensor (not shown) and input to the CZ controller 6. Output wirings 6a, 6b, 6c, 6d of the CZ controller 6 are connected to in- line chillers 3a, 3b, 3c, 3d, respectively, and output wirings of a radiation thermometer 7 for detecting the temperature of the heater 4a. 7a and the encoder output wiring of the seed shaft elevating motor (not shown) and the crucible shaft elevating motor
It is connected to the.

In the upper part of the chamber 1, there is provided a hollow tubular member vertical shaft 9 which can move up and down in the chamber 1, and a hollow tubular member surrounding the outer periphery of the Si single crystal 8 is provided at the lower end of the hollow tubular member vertical shaft 9. The member 10 is fixed. The inner periphery of the hollow tubular member 10 is provided with a gap through which an inert gas flows between the outer periphery of the Si single crystal 8, and the outer peripheral surface of the hollow tubular member 10 is
The radiant heat radiated to the Si single crystal 8 from the melt surface 11 and the inner wall of the quartz crucible 12 is reflected to the upper portion of the inner wall of the chamber.
It is made of a material having a high reflectance with a concave curved surface. The hollow tubular member 10 has a lower end and a melt surface 11.
Is adjusted by the vertical axis 9 of the hollow tubular member so as to keep a constant gap between the hollow tubular member and the shaft.

Regarding the function of the inline chiller 3,
A description will be given based on FIG. FIG. 2 is a block diagram showing the configuration of the control device. Cooling water return water pipe 32 shown in FIG. 1,
Water temperature sensor 2 mounted on each of 34, 36, 38
Output signals 1, 2, 23, and 24 are input to return water temperature calculation means 61, 62, 63, and 64 in the CZ controller 6, and calculation of each water temperature is performed. The output signal of the radiation thermometer 7 is input to the heater temperature calculating means 65, where the heater temperature is calculated, and the output signals of the seed shaft elevating motor encoder 25 and the crucible shaft elevating motor encoder 26 are calculated by the seed shaft elevating speed calculation, respectively. The means 66 is input to the crucible shaft elevating speed calculating means 67, and each elevating speed is calculated.

The cooling water temperature setting and storage means 68a for each part of the manufacturing apparatus and for each single crystal growth step stores and sets the cooling water temperature for each part such as a top chamber, a main chamber, and a heater, and for each single crystal pulling step. I have. For example, in the drawing process, T1 is applied to the load cell and the seed shaft.
1. T21 for top chamber, T31 for main chamber, T4 for heater electrode and crucible axis
1. In the shoulder expanding step, T12, T22, T
32, T42, and T13, T23, T33, T43 for each part in the straight body forming step. On the basis of these set values and the calculation results of the calculation means, the cooling water temperature availability determination means 69a for each part of the manufacturing apparatus and for each single crystal growth step determines whether or not the cooling water temperature is acceptable. A command signal V is supplied to each of the chiller 3a, the top chamber cooling chiller 3b, the main chamber cooling chiller 3c, the heater electrode, and the crucible shaft cooling chiller 3d.
C1, VC2, VC3, and VC4 are output. When it is necessary to adjust the cooling water temperature, the command signal is set to VC
1 ', VC2', VC3 ', and VC4'.

FIG. 3 is a flowchart for executing the control of the CZ controller 6, and the numbers described at the left shoulder of each step are step numbers. In step 1, a cooling water temperature command signal for each in-line chiller is output. First, in the first step, ie, the drawing step, the water temperature of the load cell and the seed shaft cooling chiller becomes T11, the water temperature of the top chamber cooling chiller becomes T21, the water temperature of the main chamber cooling chiller becomes T31, and the heater electrode and Command signals VC1, VC2, VC3, and VC4 are output to the respective chillers such that the water temperature of the crucible shaft cooling chiller becomes T41. Next, in step 2, the return cooling water temperatures t1, t2, t3, and t4 from the respective parts of the single crystal manufacturing apparatus and the heater temperature TH are read. In step 3, based on the return cooling water temperatures t1, t2, t3, and t4 and the heater temperature TH, the T
It is determined whether or not it is necessary to change 11 to T41. If necessary, in step 4, the cooling water temperature change command signals VC1 ', VC2', VC3 ', VC4' for each in-line chiller are output, and then the process returns to step 2. . If it is not necessary, the process proceeds to step 5, where the return cooling water temperatures t1, t2, t3, and t4, the heater temperature TH, the seed moving speed vs, and the crucible moving speed vc are read. In step 6, based on each data read in step 5, T11 to T
It is determined whether or not 41 needs to be changed. If this is not necessary, the process returns to step 2. If necessary, in step 7, the chiller set temperature command signals VC1, VC2, VC for the next process number, for example, the cooling water set temperatures T12, T22, T32, T42 for each part in the shoulder expanding process as the second process.
3 and VC4 are output, and the process returns to step 2.

Next, the function of the hollow tubular member 10 will be described. Radiant heat radiated from the inner wall of the hot melt surface 11 and the quartz crucible 12 is concave outer peripheral surface of the hollow tubular member 10
The light impinges on the curved surface and reflects on the upper part of the inner wall of the top chamber 1a. Further, the Si single crystal 8 and the hollow tubular member 10
The inert gas at an appropriate temperature flowing down the gap with the inner peripheral surface of the quartz crucible 12 passes through the gap between the hollow tubular member 10 and the melt surface 11.
And flows down the gap between the heater 4a and the heat retaining cylinder 13. The outer peripheral surface of the Si single crystal 8 is appropriately cooled by the inert gas, and the influence of the radiant heat from the melt surface 11 and the inner wall of the quartz crucible 12 becomes extremely small, so that the cooling rate of the Si single crystal 8 is increased. Becomes possible.

[0013]

According to the present invention as described above, according to the present invention, Ru
Towards single crystal pulled from crucible melt surface and crucible inner wall surface
The emitted radiant heat surrounds the periphery of the pulled single crystal.
The light is reflected by the concave curved surface formed on the outer peripheral surface of the hollow tubular
Reach the upper inner wall of the chamber. Therefore, first, this radiation
Direct temperature rise of inert gas or single crystal surface due to heat
Temperature rise on the single crystal surface
Can be In other words, the single crystal can be cooled in a short time.
Thus, the cooling rate of the single crystal can be improved. Second, concave songs
Large temperature rise due to radiant heat reflected from the surface
Cool the upper part with cooling water adjusted by a water temperature controller.
Therefore, the inert gas generated by hitting the top of the chamber
Convection heat is cooled, so hot convection heat is inert
Eliminates indirect heating of gas and single crystal surfaces
You. That is, the accuracy of the temperature control in the chamber is improved,
The accuracy of crystal shape and quality can be improved, and
The retention can be improved. By the way, in single crystal production,
Through the process to make the temperature suitable for each process
Is common. By the way, as mentioned above,
The temperature inside the chamber can be adjusted with high precision. This
Ri, in the temperature regulation of each process in a short time, a high speed (response
Can change and maintain the temperature. Accordingly
Therefore, the temperature in the chamber can be accurately controlled,
It is possible to obtain single crystals of good quality and high shape accuracy with high yield.
Can be. _ With such an improvement, the internal quality of the crystal , particularly the Oi concentration, is kept constant, so that a high-quality single crystal can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an embodiment .

2 is a block diagram showing the configuration of a definitive control device in the examples.

3 is a flow chart for performing a control of Examples.

[Explanation of symbols]

 Reference Signs List 1 chamber 2 cooling water supply device 3 water temperature control device (inline chiller) 4 heater electrode 5 crucible shaft 6 CZ controller 8 Si single crystal 10 hollow tubular member 11 melt surface 12 quartz crucible

Claims (2)

(57) [Claims] 1. A method according to claim 1 , wherein the melting is performed in a crucible provided in the chamber.
A single crystal from a molten semiconductor melt around this single crystal
In a single crystal manufacturing device that pulls up gas while flowing it down
The hollow tubular member surrounding the outer periphery of the pulled single crystal.
And a crucible on the outer peripheral surface of the hollow tubular member.
Check for radiant heat from heat sources such as the melt surface and the crucible inner wall.
With a concave curved surface that reflects off the upper chamber wall
And a water temperature control device for controlling the temperature of cooling water for cooling the upper portion of the chamber receiving the radiant heat reflected by the curved surface . 2. The single crystal manufacturing apparatus according to claim 1, wherein the water temperature adjusting device adjusts the temperature of the cooling water for each single crystal pulling step.