JP2001240484A - Cz method based, cooler equipped silicon single cristal silicon pulling-up device with improved effect of defect displacement by dashneck method silicon single crystal pulling-up device based on cz method and provided with cooler, enhanced in eliminating defect in dashneck method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CZ method based single crystal pulling-up device which is equipped with a cooler in a CZ furnace and is enable to smoothly dislocate a silicon seed crystal. SOLUTION: In this CZ method based single crystal pulling-up device, the cooler and a heat shelter are placed far from the surface of a melted solution in order to properly dislocate the silicon seed crystal in the dashneck method. This is based on the fact that the dislocation effect in the dashneck method is not obtained in a zone near to the cooler and the heat shelter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CZ single crystal pulling apparatus having a cooler for cooling a pulled single crystal and capable of smoothly removing dislocations from a silicon seed crystal by a dash neck method.

[0002]

2. Description of the Related Art In a CZ method single crystal pulling apparatus for pulling a single crystal by the Chocoolersky method (CZ method), an apparatus in which a cooler for cooling a pulled single crystal is installed in a CZ furnace has recently been used. ing. By using such a CZ method single crystal pulling apparatus with an in-furnace cooler, it is possible to remarkably increase the single crystal pulling speed by using the apparatus, and as a result, to increase the manufacturing efficiency of single crystal ingots and wafers. The significance of this is great.

[0003]

However, as a result of the research by the present inventors, the dash neck method (W. Dash:
J. Applied Physics 30 (1959) P459) to eliminate dislocations from silicon seed crystals (mainly, dislocations generated by thermal shock when immersing the seed crystals in the melt) It has been found that when a cooler is present, it is difficult for dislocations to escape from the silicon seed crystal.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a CZ furnace with a cooler and to smoothly remove dislocations from a silicon seed crystal by a dash neck method. An object of the present invention is to provide a CZ method single crystal pulling apparatus that can be used.

[0005]

In order to achieve the above object, according to the present invention, when dislocations are eliminated from a silicon seed crystal by a dash neck method, a cooler is used to cool a melt surface. CZ that is away from
It is intended to provide a method single crystal pulling apparatus.

In order to complete the present invention, when a heat shield is provided above the melt surface and a cooling coil is provided above the heat shield, the heat shield is provided under a specific condition using the dash neck method. The research results of the present inventors, who have experimentally clarified that it is only possible to eliminate dislocations, have contributed greatly.

[0007] As a technique similar to the present invention, in the invention described in Japanese Patent Application Laid-Open No. H11-189488, the distance between the melt surface and the lower end of the heat shield is set to a predetermined range, and at the same time, before the liquid is applied It is stated that dislocation-free operation was realized without the necking step by reducing the temperature difference between the seed crystal and the melt.However, it is not possible to realize dislocation-free operation when a cooler is present near the seed crystal. It is possible. Examples of using a cooling means above the melt for the purpose of crystal cooling include the inventions described in JP-A-4-317491 and JP-A-8-239291, but there is no dislocation after seeding. No specific method for the conversion is disclosed.

[0008] More specifically, the present invention provides the following.

(1) By adjusting the cooler for cooling the pulled single crystal provided in the CZ method silicon single crystal pulling apparatus so as to be movable in the CZ furnace, it is possible to adjust the defect elimination effect by the dash neck method. How to make it possible.

(2) While performing the seed drawing operation by the dash neck method, C is moved so as to be movable in the CZ furnace.
A method for increasing the dislocation elimination effect by the dash neck method by keeping a cooler for cooling a pulled single crystal provided in a Z method silicon single crystal pulling apparatus away from a silicon melt surface.

(3) The method according to (2), wherein the heat shield is kept away from the surface of the silicon melt together with the cooler.

In the present invention, during the seed drawing operation by the dash neck method, basically, both the cooler and the heat shield are kept away from the silicon melt surface. The position is a position that does not adversely affect the dislocation elimination effect by the dash neck method, and is most preferably a “dislocation-free region” (described in the later embodiment). As shown in the drawings with reference to the drawing, it can be regarded as a certain area mapped by the distance from the melt surface to the lower end of the cooler and the distance to the lower end of the heat shield)), and When the heat shield is located there, the same effect (dislocation elimination effect by the dash neck method) can be obtained as when the cooler and the heat shield are not present in the CZ furnace.

(4) A method of removing a pulling single crystal cooling cooler provided in a CZ method silicon single crystal pulling apparatus in order to enhance the effect of eliminating defects by the dash neck method.

(5) A cooler for cooling a pulled single crystal, a lifting device for raising and lowering the cooler in a CZ furnace,
A CZ method silicon single crystal pulling apparatus, wherein the elevating device raises the cooler during a seed drawing operation by a dash neck method. Crystal pulling device.

(6) A cooler for cooling a pulled single crystal, an elevating device for elevating the cooler in a CZ furnace,
A CZ method silicon single crystal pulling apparatus comprising: a heat shield surrounding the single crystal; and a heat shield disposed in a CZ furnace so as to be portable.
A CZ method single crystal pulling apparatus, wherein the cooler and the heat shield are raised during the seed drawing operation by the dash neck method.

(7) In the apparatus for pulling a CZ silicon single crystal according to (6), the cooler and the heat shield are provided with engaging members that engage with each other, and when the cooler is raised, The CZ method single crystal pulling apparatus, wherein the engaging members are engaged with each other and the heat shield is lifted with the rise of the cooler.

(8) A crucible for storing the silicon melt which can be moved up and down, and a cooler for cooling the pulled single crystal, wherein the silicon single crystal is pulled from the silicon melt.
A Z-method silicon single crystal pulling apparatus, wherein when performing a seed drawing operation by the dash neck method, the crucible is lowered to perform the seed drawing operation in a state where the silicon melt surface is separated from the cooler. A CZ method silicon single crystal pulling apparatus characterized by the above-mentioned.

(9) A CZ method silicon comprising: a crucible that stores a silicon melt and can be moved up and down; a cooler for cooling a pulled single crystal; and a heat shield surrounding the silicon single crystal that is pulled from the silicon melt. In a single crystal pulling apparatus, when performing a seed drawing operation by a dash neck method, the crucible is lowered and the seed drawing is performed in a state where the silicon melt surface is separated from the bottom surfaces of the cooler and the heat shield. An apparatus for pulling a CZ silicon single crystal, which performs an operation.

(10) A silicon ingot manufactured by the CZ method single crystal pulling apparatus according to any one of (5) to (9).

(11) A silicon wafer cut from the silicon ingot according to (10).

When a wafer is cut out from a silicon ingot, it is general to cut out the silicon ingot from a product target area. However, in some cases, such as when cutting out a wafer for research or a dummy, the wafer may be cut out. May be cut out from the shoulder or tail.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a CZ according to the present invention.
1 is a block diagram showing a preferred embodiment of a method single crystal pulling apparatus.

[Overall Structure] A CZ method single crystal pulling apparatus according to the present invention, like a normal CZ method CZ method single crystal pulling apparatus, includes a silicon melt 1 in a closed chamber 11.
And a crucible 13 for manufacturing and storing
And a heater 14 for heating the heater. In addition to the above, an electrode for supplying power to the heater 14, a crucible receiver for supporting the crucible 13, a pedestal for rotating the crucible 13, a heat insulating material, and a melt, similarly to a normal CZ method single crystal pulling apparatus. Receive, inner cylinder, etc. are provided. Also, this apparatus includes a silicon melt 12
Further, a heat shield 18 for shielding heat radiation from the heater 14 to the pulled single crystal 17 and a cooler 19 arranged inside the heat shield 18 are provided.

In such a CZ method single crystal pulling apparatus, the single crystal is pulled while the pulling single crystal 17 and the crucible 13 rotate in the opposite directions, similarly to a normal CZ method CZ method single crystal pulling apparatus. Here, the crucible 13 is a crucible 13
The crucible 13 moves up and down by a lifter (not shown) provided at the lower part of the crucible. Unless otherwise specified, the vertical movement of the crucible 13 is performed in such a manner that the crucible 13 rises in accordance with the lowering of the silicon melt surface 12a due to the lifting of the silicon single crystal ingot.

Although not particularly shown, the CZ single crystal pulling apparatus according to the present invention includes an inert gas introduction / exhaust system normally provided in this type of CZ single crystal pulling apparatus. ing. Under such a system, the heat shield 18 also has a function of adjusting the flow path of the inert gas. In this apparatus, a vacuum pump 20 for exhausting the inside of the chamber 11 is connected (means for detecting the opening of the throttle valve or detecting the amount of supplied electric power). Is provided on the vacuum pump 20,
It is not necessary to separately provide a pressure sensor described later).

Further, the CZ method single crystal pulling apparatus according to the present invention is provided with solenoids 51 and 52 for applying a cusp magnetic field to the silicon melt 12. By applying a cusp magnetic field to the silicon melt 12 by the solenoids 51 and 52, minute convection generated in the silicon melt 12 can be eliminated, and the reduction of crystal defects and the stable pulling are further promoted. Will be able to do it.

Further, as shown in FIG. 2, the CZ method single crystal pulling apparatus according to the present invention comprises a silicon melt surface 12a.
And a melt level sensor 45 for detecting the distance between the silicon shield liquid surface 12a and the bottom of the cooler 19, and the liquid surface that changes due to the vertical movement of the crucible. The level can be accurately detected. For this reason, the distance between the bottom of the heat shield 18 and the silicon melt surface 12a and the distance between the bottom of the cooler 19 and the silicon melt surface 12a are dash necks which will be described later. The distance can be controlled accurately so that the defect elimination effect by the method can be obtained.

[Cooler] In the CZ single crystal pulling apparatus according to the present invention, a cooler 19 composed of a pipe through which cooling water flows is disposed inside the heat shield 18. As shown in FIGS. 1 and 2, the cooler 19 is composed of a stacked body of pipes (cooling pipe stack) surrounding the pulled single crystal 17, and cooling water is circulated through the pipes. The cooling water is supplied through a supply pipe 21a. A bellows member 23 is attached to a location where the supply / discharge pipe 21 (comprising a set of the supply pipe 21a and the discharge pipe 21b) including the supply pipe 21a penetrates into the chamber 11, thereby maintaining airtightness. It has been like that.

In this embodiment, the inside diameter of the pipe constituting the cooler 19 is about 17 mm, and the flow rate of the cooling water flowing through the pipe is set to 15 liter / min or less. Here, when the diameter of the pipe is reduced,
If it is made too small, a sufficient cooling effect will not be obtained, but if it is made to some extent, the cooling effect will not be significantly affected. In this case, the amount of water remaining in the cooler 19 is reduced, so that damage to the water leak in the event of the breakage of the cooler 19 can be reduced.

The distance between the lower end 19a of the cooler 19 and the silicon melt surface 12a is usually set to about 150 mm. By installing the cooler 19 in the CZ furnace, the crystal defect size can be reduced by increasing the temperature gradient in the single crystal straight body, and at the same time, the pulling speed of the silicon single crystal ingot can be increased, thereby increasing the production. Improvement of efficiency can be realized.

[Movement of cooler] <Cooler elevating device (vertical vertical movement in vertical direction)>
A characteristic of the CZ method single crystal pulling apparatus according to the present invention is that a cooler 19 formed of a pipe through which cooling water flows moves in the CZ furnace. In this embodiment, First of all, the movement of the cooler 19 is shown in the embodiment "elevation".

That is, in the CZ method silicon single crystal pulling apparatus with a cooler according to the present invention, as shown in FIG. 1, an elevating apparatus 25 for raising and lowering a cooler 19 in a CZ furnace.
The cooling pipe stack of the cooler 19 surrounding the pulling single crystal 17 is moved up and down by the driving of the elevating device 25.

FIG. 2 is a block diagram for explaining the functional configuration of the lifting device 25. As shown in FIG. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In addition, for the sake of simplicity, members and components unnecessary for the description are omitted, while members and components omitted in FIG. 1 are appropriately added.

As shown in FIG. 2, in this embodiment, an elevating device 25 includes an elevating block 23a (cross-linking member) attached to an upper portion of a bellows member 23, and a screw rod screwed to the elevating block 23a. It comprises a body 25a and a motor 26a for rotating the screw rod body 25a. In this embodiment, the screwing of the lifting block 23a and the screw rod 25a is performed by a ball screw.

According to the lifting device 25 having the above-described configuration, there is an advantage that the axial movement of the screw rod can be surely performed, and the moving speed can be appropriately and freely changed. More specifically, it is possible to freely perform not only the constant speed movement in the axial direction of the screw rod body but also the sudden stop and the change of the reverse rotation position moving speed.

Incidentally, in the CZ method single crystal pulling apparatus according to the present invention, 30 mm / min and 300 mm / mi
It is assumed that the moving speed changes in two stages of n, and the function will be used for ensuring the safety of the device described later.

According to the elevating device 25 having the above-described configuration, even when the motor 26a as the driving mechanism is stopped, the cooler is supported and the position of the cooler is maintained. It also saves energy.

Incidentally, all types of elevating devices described in this embodiment are made of stainless steel in order to cope with the magnetic field when a magnetic field is applied to the silicon melt as shown in FIG. It is necessary to take some countermeasures, for example, to install in a position free from the influence of a magnetic field, or to cover with a housing.

<Diagonal Movement> FIG. 3 is a block diagram for explaining an embodiment in which the cooler moves diagonally. In the figure, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the equivalent components having the same functions are denoted by the same reference numerals in the 100's in the last two digits.

As shown in FIG. 3, in a cooler that moves in an oblique direction, the elevating device itself is the same as that of the cooler of the vertical movement type shown in FIG. The difference is that the stack is divided into two. Due to such a characteristic configuration, in the CZ method silicon single crystal pulling apparatus with a cooler according to this embodiment, when the cooler rises in an oblique direction, the cooling pipe stack is opened.

The structure and operation of the CZ method silicon single crystal pulling apparatus with a cooler according to this embodiment will be specifically described. In this apparatus, an elevating apparatus 125 for moving a cooler 119 composed of a cooling pipe stack in an oblique direction.
Is basically the same as the elevating device 25 shown in FIG. 1, and the elevating device 125 includes an elevating block 123 a (bridge member) attached to the upper part of the bellows member 123,
A screw rod body 125a screwed with the lifting block 123a
And a motor 126a for rotating the screw rod 125a
And consisting of In this embodiment, the screwing of the lifting block 123a and the screw rod body 125a is also performed by a ball screw, similarly to the lifting device 25 shown in FIG.

Here, a characteristic of the cooler according to this embodiment is that a cooler 119 constituted by a cooling pipe stack is divided into two cooler blocks 119a and 119b. As shown in FIGS. 4A and 4B, each of the cooler blocks 119a and 119b is formed by winding a cooling tube so that the entire block has a semi-cylindrical shape, and the cooler block 119a and the cooler block 119b are respectively provided. Are combined to form a cylindrical shape (FIG. 5).
A). For this reason, even if it moves in an oblique direction, the predetermined position of the single crystal can be cooled by the cooler and can be retreated to another place when unnecessary.

The cooler 11 of the obliquely moving type as described above.
9 is not suitable for use in changing the cooling position of the single crystal, but is more suitable for switching between setting and canceling of the cooling pulling environment than the vertically movable cooler shown in FIG. It has the advantage that it can be done simply and quickly.

In this embodiment, only the semi-cylindrical cooler blocks 119a and 119b constituting the obliquely moving cooler 119 are shown (see FIG. 5A). However, the present invention is not limited to this. For example, a cylinder formed by dividing a cylinder into three at a central angle of 120 degrees (see FIG. 5B) and a cylinder divided into four at a central angle of 90 degrees (see FIG. 5C) are all integrated. Any form that can form a cylindrical shape or a shape close to a cylindrical shape can be adopted. As a matter of course, the central angle in the case of division may not be uniform (see FIG. 5D).

<Rotational Movement> FIG. 6 is a block diagram for explaining an embodiment of a CZ method silicon single crystal pulling apparatus equipped with a cooler having a cooler that rotates. In the figure, the same components as those of the CZ method silicon single crystal pulling apparatus with a cooler provided with a vertically movable cooler shown in FIG. Are given the same reference numbers in the 200s.

As shown in FIG. 6, the cooler 219 of the rotary position type is also composed of a stack of cooling pipes, similarly to the cooler 19 of the vertical movement type, through which cooling water flows. Cool the single crystal.

The characteristic of the cooler 219 of the rotary position type is that the cooler 21
9 is to rotate. That is, in the CZ method silicon single crystal pulling apparatus shown in FIG. 6, after the cooler 219 is lifted by the rotational movement of the cooler 219 (FIG. 6A), the bellows member 223 extends, and the bellows member 2 extends.
Cooler 219 is accommodated in 23 (FIG. 6B).

Here, the expansion and contraction of the bellows member 223 is performed by the horizontal moving device 225.
25 is a cooler 19 of the vertical movement type shown in FIG.
3 and a moving block 223a attached to the end of the bellows member 223, and a screw rod screwed to the moving block 223a. It comprises a body 225a and a motor 226a for rotating the screw rod 225a. And such a horizontal movement device 225
According to the above, the moving block 223a is horizontally moved with the rotation of the motor 226a, and the expansion and contraction of the bellows member 223 and the insertion and removal of the cooler 219 are performed in the same manner as in the above-described lifting device.

It should be noted that such a rotary-position-moving cooler 2
In the CZ method silicon single crystal pulling apparatus with a cooler provided with the cooler 219, the shape of the cooler 219 is such that the cooler 219 can pass through the single crystal 17 when the cooler 219 is lifted as shown in FIG. In order to do this, it is not completely cylindrical,
It is necessary to have a gap 219x larger than the diameter of 7a. However, without adopting such a mode, a split-type cooler as shown in FIGS. 5A to 5D may be used.

[Removal of Cooler] The cooler was removed after the silicon single crystal ingot was pulled up.
This is performed by withdrawing the supply / discharge pipe from inside the Z furnace.

Regarding this operation and related members, a CZ method single crystal pulling apparatus with a cooler equipped with a cooler 19 of a vertical movement type shown in FIG. 1 will be described as an example. The same can be applied to other types of devices as long as they are provided.

First, the cooler 19 is removed by pulling out the supply / discharge pipes (21a, 21b) from the inside of the CZ furnace after pulling up the silicon single crystal ingot. Here, as shown in FIG. 8, the cooler 19 is provided with a fixing jig 60 provided on the top of the bellows member 23.
Is fixed to the lifting block 23a. Also,
A cover 70 is provided as a member for closing a hole opened in the elevating block 23a after the cooler 19 is removed. Since the lid 70 is for compensating for a state where the cooler 19 is not present, the fixing jig 60 and the lid 70 have a shape homologous to each other in order to have interchangeability.

Here, the fixing jig 60 and the lid 70
As shown in FIG. 8, both of them have a flange member extending parallel to the outer surface of the lifting block 23a, and have a basic structure of fixing the flange member with screws. . First, as shown in FIG. 8B, the lid 70 is made of a cylindrical body 70a provided with a disk-shaped flange 70b at the top, and is fitted to the elevating block 23a with screws 70c. The screw is fixed. An O-ring 70d for maintaining airtightness is wound around the cylindrical body 70a.

On the other hand, as shown in FIG. 8A, a fixing jig 60 includes a cylindrical body 61 having a circumferential groove 61a formed thereon and a pair of semicircular rings fitted into the circumferential groove 61a of the cylindrical body 61. The cylindrical body 61 is provided with a through hole 61b through which the supply / discharge pipes (21a, 21b) are passed (FIG. 8C). An O-ring 61d for maintaining airtightness is wound around the cylindrical body 61, similarly to the body 70a of the lid 70.

In such a fixing jig 60, a pair of semicircular ring-shaped plate members 62 a and 62 b are fitted into the grooves 61 a of the cylindrical body 61. In this state, the semicircular ring-shaped plate members 62a and 62b are fixed to the cylindrical body 61 by screws 63a and 63b, so that the semicircular ring-shaped plate members 62a and 62b have the shape of a cylindrical body having a flange member, and can exhibit the same function as the lid body 70. become. Then, in this state, the fixing jig 60 is fixed to the semicircular ring-shaped plate members 62a and 62a.
The screws 64a and 6
The screw is fixed to the lifting block 23a by 4b.

As described above, both the fixing jig 60 and the lid 70 (the fixing jig 60 has a bolt-like shape when the semicircular ring-shaped plate members 62a and 62b are fitted).
It is a bolt-like member without any thread, which is fitted into the hole of the lifting block 23a, and as a replaceable one, the fixing jig 60 and the lid 70 constitute one set, so to speak. Therefore, the attachment and detachment of the cooler 19 can be easily performed. For this reason, it is possible to easily and freely switch between the presence and absence of a cooler, and to use it as a CZ method single crystal pulling apparatus equipped with a CZ furnace with a cooler on a case-by-case basis, and a cooler on another occasion. It can be easily used as an ordinary CZ method single crystal pulling apparatus without the method.

[Recharging / Charging] The quartz crucible is damaged by heating when melting the polycrystal, and is usually discarded for each pulling process. Therefore, if the amount of single crystal pulled in a single pulling process can be increased, not only can the manufacturing cost be reduced, but also if the same amount of single crystal is manufactured, the process of cooling and raising the temperature can be performed. Can be reduced, leading to a reduction in the time required to produce a certain amount of single crystal, and to improve the efficiency of the entire production process. In particular, if the pulling amount of the single crystal can be pulled to the limit of serviceability as a quartz crucible for pulling a single crystal, the greatest effect such as cost reduction from this aspect can be obtained. .

Recharging and follow-up charging are means for obtaining such an effect.
As shown in the figure, when the raw material polysilicon is charged into the crucible and melted, if the crucible is not fully charged due to the bulk of the raw material polysilicon, additional raw material polysilicon is added to the raw material melt. Then, the amount of the melt is increased, and then the single crystal is pulled in the same manner as in a normal case.

On the other hand, as shown in FIG. 9B, the recharge is performed again after the single crystal has been pulled to some extent.
This refers to charging a raw material polysilicon into a crucible to pull up a single crystal.

According to such recharging / charging, the amount of single crystal pulled in one pulling process can be increased, so that not only can the manufacturing cost be reduced, but also the crucible can be significantly raised. Since the temperature is not lowered, the life of the crucible is prevented from being shortened, and the heating time can be extended. The length of the obtained single crystal can be increased. Also, by using the cooler together with the cooler, the increase of the pulling rate of the single crystal per unit time based on the improvement of the pulling speed by the cooler is synergistic, so that the manufacturing efficiency can be improved as a whole.

Here, the cooler 19 and the heat shield 18 are
In order to exert their functions sufficiently, they are usually arranged at a position as close to the surface of the melt as possible. However, when performing recharging or recharging, the cooler 19 and the heat shield 18 are melted. Being close to the liquid level is by no means desirable in view of the problem of contact with these members and liquid splash due to the rise of the melt liquid level.

[0062] Regarding this, there is a similar problem when the crucible is normally charged, and in order to increase efficiency and to make the crucible as close to full charge as possible,
Inevitably, the deposition amount of the raw material silicon increases, but if this is done, during the melting process, the raw material polysilicon stacked on the upper side falls and the raw material melt splashes. Therefore, there is a concern that it may adhere to the cooler 19 and the heat shield 18.

In order to solve such a problem, in the CZ method single crystal pulling apparatus with a cooler according to the present invention, charging of the raw material into the crucible, dissolution of the raw material, and execution of recharging and recharging are performed. At this time, the cooler and the heat shield are retracted upward (FIG. 10). In this case, the mechanism for moving the cooler may use the elevating device described above. Also, from the viewpoint of work efficiency, the speed at the time of retreating upward is a high speed (300 mm / min).
It is preferred that

If the method according to the present invention is adopted, for example, as shown in FIG. 11, even when the bottom heater 16 is separately attached and the heating power is further increased, the cooler 19 and the heat shielding The body 18 is retracted upward to prevent the liquid splash from adhering, and the increased heating power can be effectively used for melting the material.

[Movement of Heat Shield Following Cooler]
FIG. 12 is a longitudinal sectional view in the CZ furnace for describing the structure and function of the heat shield and the cooler according to the present invention.

As shown in FIG. 12A, a characteristic of the present invention is that the side of the cooler 19 is provided with an ear member 81a.
Is attached. On the other hand, on the inner wall side of the heat shield 18, an engaging body 18a that engages with the ear member 81a is provided. Correspondingly, the heat shield 18 is placed on the base member 83 in the CZ furnace.
It is merely mounted on the base member 83 without fixing such as screw fixing or bonding. Therefore,
The heat shield 18 can be easily separated from the base member 83 by lifting.

That is, in the CZ method single crystal pulling apparatus with a cooler according to the present invention, as shown in FIGS. 12B and 12C, when the cooler 19 is in the normal position, the lug 81a engages with the ear member 81a. The engagement with the member 18a is not performed, and the normal cooler 19a is in the same state as the heat shield 18, but as shown, the ear member 81
The ear member 81a and the engaging body 18a engage with each other when the cooler 19 rises, and the heat shield and the cooler 19 are heat shielded. The body 18 also rises away from the base member 83.

As shown in FIG. 12C, the ear member 81a and the engaging member 18a are not provided over the entire circumference of the cooler 19, but are provided at a part thereof. In FIG. 12C, each of the ear member 18a and the corresponding engaging member 81a is
Although these are provided individually, for example, as shown in FIG. 12D, three of them may be provided around the cooler 19, and furthermore, in consideration of the function of the entire apparatus, etc. It is also possible to provide several.

FIG. 13 shows a cooler 1 according to the present invention.
9 is a diagram for explaining the operation of the heat shield 9 and the heat shield 18. FIG. Note that the same reference numerals are given to the components in FIGS. 12 and 11 and the description thereof will be omitted.

First, as shown in FIG. 13A, the cooler 19 is located at the lowest level position as a fixed position. Then, as shown in FIG. 13B, the cooler 19 rises, and as shown in FIG. 13C, when the ear member 81a and the engaging member 18a are engaged, the heat shield 18a is lifted. (FIG. 13D). In addition, from the opposite viewpoint, FIG.
As shown in FIG. 3B, the ear member 81a and the engagement member 18a
Until the air conditioner is engaged, the cooler 19 is
This means that you can go up and down freely regardless of the situation.

When the ear member 81a according to the present invention is constructed, the ear member 81a is bonded to the side surface of the cooler 19 made of metal, so that the ear member 81a engages with the heat shield 18 and lifts it. It is generally difficult to provide strength. Therefore, in the present invention, as a preferred embodiment, a support plate 81 as shown in FIG. 14 is formed, and the ear plate 81 a is protruded from the side wall of the cooler 19 by sandwiching the support plate 81 in the spiral of the cooler 19. I have to. That is, the support plate 81 is
9 and an ear member 81a projecting from the periphery of the annular portion 81b. When the ear member 81a is inserted into the cooler 19, as shown in FIG. The ear member 81a protrudes from the side wall, and has sufficient strength to lift the heat shield 18. The support plate 81 can be made of a heat-resistant material such as a carbon material.

In the CZ single crystal pulling apparatus with a cooler according to the present invention, the cooler 19 is moved to the upper part in order to shorten the melting time at the time of the initial melting of the raw material or at the time of additional charge / recharge melting. To move away from the melt surface. At this time, in this embodiment, the heat shield 18 is also raised upward in accordance with the cooler 19, so that the cooler 19 becomes a shadow of the heat shield 18 on the melt surface. Therefore, the heating efficiency for dissolving the raw materials increases. In any case of the initial melting or the additional charge / recharge melting, it is preferable to shorten the melting time by increasing the output ratio of the bottom heater 16 particularly when melting the raw material.

The cooler 19 is moved up and down at a high speed when moving upward for the above-mentioned purpose or when retracting the upper portion for ensuring safety. Gradually lower the temperature to avoid changes in the thermal environment.

The operation at the time of executing the additional charge / recharge has been described in the present specification by taking as an example a CZ single crystal pulling apparatus with a cooler having a vertically movable cooler. The objective can be achieved as long as the cooler moves to a position away from the melt or crucible when performing additional charge / recharge, so a cooler equipped with another type of movable cooler such as a diagonal movable cooler or a rotary cooler Obviously, the present invention can be applied to a CZ method single crystal pulling apparatus.

[Dashneck Method and Cooler] According to the study of the present inventors, when a cooler was present near the seed crystal while the seed crystal was being drawn by the dashneck method, it was generated by thermal shock. It has been found that the dislocations cannot be removed from the seed crystal and a single crystal cannot be produced (Table 1).

[0076]

[Table 1]

That is, as shown in Table 1, when the distance between the heat shield 18 and the melt surface is 20 mm, even if the distance between the cooler 19 and the melt surface is small (75 m).
m) Even if it was large (125 mm), dislocation-free seed crystals could not be obtained (as shown in Table 1, the dislocation-free rate was 0% in each case). On the other hand, the heat shield 1
When the distance between the melt 8 and the melt surface is set to 30 mm or 40 mm, the distance between the cooler 19 and the melt surface is small (85 mm) or large (115 mm), and no seed crystal is formed. The dislocation conversion ratio was 100% (as shown in Table 1, in the case of 30 mm, 15 out of 15 dislocations are missing). When the cooler 19 was not installed (right end in Table 1), even if the distance between the heat shield 18 and the melt surface was 20 mm, the dislocation-free ratio of the seed crystal was 100%. Was obtained.

As described above, when the cooler does not exist, the seed crystal can be made dislocation-free even if the lower end of the heat shield exists near the melt surface.
When a cooler is present, the lower end of the heat shield is located at a certain distance from the melt surface (at least 3 mm from the melt surface).
It can be seen that the seed crystal cannot be dislocation-free unless it is at a position separated by about 0 mm).

Assuming a region where dislocations can be eliminated based on such a fact, the region shown in FIG. 15 is obtained. The specific numerical value of the boundary portion of the dislocation-free region shown in FIG. 15 is determined by the size and state of the CZ furnace, the shape of the in-furnace member used, and the like. For example, in this embodiment, The point P in the figure will be 30 mm.

As described above, the cooler 19 and the heat shield 1
8, dislocations do not escape near the melt surface, and from another perspective, in order to successfully remove dislocations from the seed crystal in the dash neck method, the heat shield 18 and the cooler 19 must be melted. It is necessary to keep it away from the liquid surface.

Accordingly, in the present invention, while dislocations are eliminated by the dash neck method, the cooler 1
9 and the heat shield 18 are controlled so as to be separated from the melt surface. As to how much the cooler 19 and the heat shield 18 are separated from the melt surface, the dislocation-free region shown in FIG. 15 is determined by changing the size and state of the CZ furnace, the shape of the furnace internal member used, and the like. The boundary condition is determined after the boundary condition is specifically determined, and the cooler 19 and the heat shield 18 are moved so as to enter the dislocation-free region.

Then, after the dislocation is sufficiently removed from the seed crystal by the dash neck method, the cooler 19 and the heat shield 1
8, the single crystal is pulled up while cooling. In the course of this operation, the movement of the cooler 19 and the heat shield 18 is basically performed at a high speed (300 mm / mm) from the viewpoint of work efficiency and the like.
min).

Although the operation of the cooler when dislocations are eliminated by the dash neck method has been described in this specification, a CZ single crystal pulling apparatus with a cooler equipped with a vertically movable cooler has been described as an example. The purpose of the present invention is that the cooler and the heat shield only need to be located at a predetermined distance from the melt surface while dislocation elimination by the dash neck method is performed, so that the obliquely moving cooler and It is apparent that the present invention can be similarly applied to a CZ method single crystal pulling apparatus equipped with a cooler having another type of movable cooler such as a rotary cooler.

[Relationship between Moving Speed and Position of Cooler—In All Steps of Pulling Single Crystal] FIG. 16 is a view for explaining the operation of the CZ single crystal pulling apparatus with a cooler according to the present invention. The moving speed of the cooler is shown on the lower side, and the position of the cooler is shown on the upper side.

First, in the process of performing additional charging and necking (steps (a) and (b)), the cooler 19 is stopped at a high position away from the melt surface. Then, when necking ends, the cooler 19 descends and stops when it reaches a predetermined position (step C). The movement at that time is performed at a high speed to speed up the work. If it becomes necessary to re-attach the seed crystal, the cooler 19 is raised again and placed at a high position,
Necking is performed in this state.

Then, when the single crystal is pulled while the cooler has been lowered to a predetermined position (step d),
Since the pulling is performed while cooling the single crystal, the pulling speed can be increased. Here, when the pulling of the single crystal is completed, the cooler 19 rises again at a high speed (step E), and the cooler 19 is stopped at an upper position to perform remelting (step F). When the remelting is completed, the cooler 19 descends again at a high speed (step T), and the single crystal is pulled again (step H). In the tail step (process step), which is the final step of pulling a single crystal, the cooler 19 is raised in order to reduce power consumption. However, in order to secure a sufficient product solution, the cooler 19 is raised with a slight delay. I try to make it.

Next, when performing recharging (step n), as described above, the cooler 19 is raised at a high speed in order to ensure the ease of charging and to avoid harm of liquid splash. And will be placed higher up. When the recharge is completed, the cooler 19 descends again at a high speed (step 1), and the single crystal is pulled up (step 1). In the single crystal pulling step (step ヲ), if a collision or accident occurs, the cooler 19 is immediately raised to keep it away from the silicon melt surface. The tail step (step W) after pulling the single crystal is the same as the tail step (step d) described above, and thereafter, the cooler 19 descends into the crucible, and the crucible is cooled. (Step yo).

<Operation for Ensuring Safety and Avoiding Danger> The CZ method single crystal pulling apparatus according to the present invention is basically used as an operation for ensuring safety and avoiding danger, basically, in a place where an abnormal situation occurs, in a place where melting occurs. A mode is adopted in which the cooler is moved away (evacuated) from the liquid surface or the pulled single crystal. As a more specific mode, for example, the “abnormal situation” is the cooler 1
In the case of collision or abnormal approach between the furnace 9 and other furnace members, the cooler 19 may be temporarily moved in the opposite direction by about 5 mm. If the "abnormal situation" is a collision between furnace members other than the cooler 19 or a malfunction of the apparatus, the cooler 19 is moved away from the single crystal 17 or the silicon melt 12. By doing so, danger is avoided and maintainability of the CZ method single crystal pulling apparatus is improved.

In this case, when retreating from a dangerous place represented by the single crystal 17 or the silicon melt 12, the moving speed of the cooler 19 is changed at a high speed (3).
0 mm / min → 300 mm / min)
Rapid risk avoidance is realized.

Here, the abnormal state detection mechanism / device includes the detection of the temperature of the cooling water flowing in the cooler, the monitoring of the temperature distribution in the CZ furnace, the detection of the relative position of the members in the furnace, and the detection of the cooler and the single crystal pulling motor. Overload detection, abnormal weight change detection,
Although the detection of the movement amount by an encoder installed in the mobile cooler can be mentioned, in this specification, the function and configuration in the case of ensuring safety by detecting water vapor will be described with reference to FIG.

As shown in FIG. 1, in the CZ method single crystal pulling apparatus according to this embodiment, the chamber 11
A pressure sensor 31 for tracking a pressure change in the chamber, a temperature sensor 33 for monitoring a temperature change of a gas in the chamber 11 sucked by the vacuum pump 20, and an infrared absorption of the gas in the chamber 11 sucked by the vacuum pump 20. Seeing infrared sensor 34
And is attached. This is because when water leaks from the piping of the cooler 19, the water in the furnace turns into water vapor due to heat in the furnace, which causes a temperature change or a pressure change. It is intended to accurately detect. The infrared sensor 34 is installed to increase the reliability of water leak detection by measuring the water vapor, which has infrared absorption, by measuring the infrared absorption.

If any one of these sensors is installed, it is sufficiently possible to detect a water leak. However, from the viewpoint of thorough detection, a plurality of sensors are appropriately combined and installed. You may make it. Further, from a similar viewpoint, it is not hindered to install a plurality of sensors of the same type.

The temperature sensor 33 does not respond to changes in other conditions unless a relatively large amount of water vapor is present. To be attached to the evacuation path (ie, the vacuum pump 2).
(Pipe connected to 0). On the other hand, since the infrared sensor 34 can immediately detect even a small amount of water vapor, the infrared sensor 34 can be attached not only to the exhaust path but also to any part such as the inner wall surface of the chamber 11.

Here, each of the sensors is connected to the controller 3
5 is connected. In this embodiment, the pressure sensor 31 is directly connected, the temperature sensor 33 and the infrared sensor 34 are connected to the corresponding processing units 33a and 34a, respectively.
Is connected to the controller 35 via the.

For example, the chamber 11 by the generation of water vapor
When the pressure increase in the inside was detected by the pressure sensor 31, when the temperature rise of the exhaust gas due to the generation of water vapor was detected by the temperature sensor 33, abnormal absorption in the water vapor absorption band was recognized by the infrared sensor 34. In this case, or when these situations are detected at the same time, the controller 35 operates to turn on the display 36, close the electromagnetic valve 37 for adjusting the inflow of cooling water, and stop the inflow of cooling water. At the same time, the normally closed solenoid valve 3
9 is opened to open the end of the discharge pipe 21b to the atmosphere. Then, if a water leak occurs, the water leaks into water vapor and the pressure increases. In this case, the cooling water in the cooler 19 is discharged to the outside through the solenoid valve 39 and the silicon melt is discharged. The amount of water falling inside can be reduced.

The pipe for opening to the atmosphere is also connected to the supply pipe 21a, so that what is about to be supplied into the cooler 19 can be discharged. For this reason, at the time of water leakage, the cooling water remaining in the cooler 19 is discharged as much as possible, so that the damage to the device is reduced, and even in such a case, the operation stop of the device can be avoided. Become. However, in the CZ method single crystal pulling apparatus according to the present embodiment, a safety valve 40 is attached to the chamber 11 as a countermeasure in order to ensure an emergency. In addition, a check valve 4 is installed on the outflow pipe of cooling water and the pipe open to the atmosphere.
1, 42, and 43 are attached to ensure emergency situations.

Here, the "abnormal situation has occurred" in the CZ method single crystal pulling apparatus includes, for example, detection of an operator, power failure, failure of a vacuum pump, failure of a heater power supply, breakage of furnace components, and cooling. When such an "abnormal situation" occurs, at least the motor 26a of the elevating device 25 is stopped, and in some cases, the motor 26a is reversely rotated so that the cooler 1
Turn 9 back in the opposite direction to avoid a serious accident. Furthermore, in order to avoid serious accidents, in the event of "an abnormal situation", if the cooler is in close proximity, dangerous furnace components (silicon melt surface or pulled single crystal) It operates to move the cooler away at a high speed (300 mm / min).

[0098]

The C with a cooler according to the present invention as described above
In the Z method single crystal pulling apparatus, a cooler for cooling the single crystal is installed in the CZ furnace, such as a problem at the time of additional charge / recharge and a problem at the time of dislocation-free by the dash neck method. Therefore, it is possible to avoid the problem caused by the above, and to enjoy only the merit of providing the cooler such as increasing the crystal pulling speed. Therefore, for example, the crystal pulling speed is set to 1.
The effect of quintuple can be surely obtained without the disadvantage of the cooler installation.

More specifically, first, in the CZ method single crystal pulling apparatus with a cooler according to the present invention, it is possible to reduce the problem of increase in energy consumption of the CZ single crystal pulling apparatus with a cooler. it can. That is, in the CZ method single crystal pulling apparatus with a cooler as described in this specification, the crystal is provided by providing a cooler between the heat shield and the crystal for shielding heat from the raw material melt to the crystal. Can be 1.5 times faster than before.
On the other hand, there is a problem of an increase in energy consumption. However, in the CZ method single crystal pulling apparatus with a cooler according to the present invention, at the time of initial melting or additional charge / recharge melting, a cooler (in some cases, a heat shield is also used). At the same time) is moved upward and away from the melt surface, so that the output of the heater is correspondingly reduced and the increase in energy consumption is suppressed.

Further, in the CZ method single crystal pulling apparatus with a cooler according to the present invention, the problem at the time of additional charging and recharging caused by the problem of the durability time of the quartz crucible is solved.
That is, when additional charging or recharging is performed, the state in which the quartz crucible is heated becomes longer, and when recharging is performed due to deterioration of the quartz crucible or the problem of durability time, crystal collapse after recharging ( Although the problem of a decrease in the acquisition rate due to an increase in the (polycrystallization) rate and the problem of a decrease in the acquisition rate due to an increase in the crystal collapse (polycrystallization) rate in the latter half of the crystal occur when additional charge is performed, In the CZ method single crystal pulling apparatus with a cooler according to the present invention, the pulling speed of the crystal can be surely increased to 1.5 times or more of the conventional method without the disadvantage of the cooler installation, and the heating time of the quartz crucible can be reduced. Therefore, it is possible to increase the dislocation-free ratio in both the additional charge crystal and the recharge crystal. In addition, due to problems such as durability, an expensive synthetic quartz crucible had to be used in the past to avoid an increase in the polycrystallization rate, but by applying the present invention, an inexpensive natural quartz crucible can be used. It is also possible to use it.

Further, in the CZ single crystal pulling apparatus with a cooler according to the present invention, dislocation-free by the dash neck method can be surely performed even with the cooler, so that the production efficiency is improved, This can contribute to a reduction in production costs.

Furthermore, even if the furnace internal members are deformed due to long-term use, etc., the distance between the melt surface and the cooler and the distance between the heat shield and the cooler are reduced. Since the setting can be made so that substantially the same condition is maintained by adjustment, it is possible to continue mass-producing crystals of stable quality.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a preferred embodiment of a CZ method single crystal pulling apparatus according to the present invention.

FIG. 2 is a block diagram for explaining a functional configuration of an elevating device of the CZ method single crystal pulling device according to the present invention.

FIG. 3 is a block diagram illustrating an embodiment in which a cooler moves in an oblique direction.

FIG. 4 shows an embodiment of a cooling pipe stack of a cooler moving diagonally. In particular, FIG. 4A is a side view,
FIG. 4B is a top view.

FIG. 5 shows a variation of an embodiment of a cooling pipe stack.

FIG. 6: C with cooler provided with a cooler that rotates
It is a block diagram for explaining embodiment of a Z method silicon single crystal pulling device.

FIG. 7 illustrates an embodiment of a cooling pipe stack of a cooler that rotates.

FIG. 8 is a diagram showing a configuration of a jig used for a joint between a supply / drainage pipe of the cooler and an elevating block, and a lid for covering a hole after the cooler is removed. In particular, FIG. 8A is a longitudinal sectional view of the jig, FIG. 8B is a longitudinal sectional view of the lid, FIG. 8C is a top view of the jig, and FIG. 8D is a diagram for explaining the structure of the jig.

FIG. 9 is a diagram for explaining an additional charging step (A) and a recharging step (B).

FIG. 10 is a block diagram for explaining operations at the time of additional charge and recharge.

FIG. 11 is a block diagram for explaining operations at the time of additional charging and recharging, and is a diagram showing an embodiment in which a bottom heater is installed.

FIG. 12 is a view for explaining an embodiment in which the heat shield 18 moves up together with the cooler 19;

FIG. 13 is a view for explaining the operation of the embodiment in which the heat shield 18 moves up together with the cooler 19;

FIG. 14 is a diagram for explaining a configuration of a support plate 81.

FIG. 15 is an imaginary view showing a region where dislocations can be eliminated by the dash neck method in relation to the distance from the melt surface to the lower end of the heat shield and the distance from the melt surface to the lower end of the cooler. .

FIG. 16 is a view for explaining the elevating operation of the cooler in the present invention, and shows the position of the cooler (upper part).
FIG. 3 is a diagram showing time and a moving speed (lower part) over time.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Chamber 12 Silicon melt 12a Silicon melt level 13 Crucible 14 Heater 15 Wire 16 Winder 17 Silicon ingot 17a Seed crystal 18 Heat shield 18a Engagement member 19, 119, 219 Cooler 119a, 119b Cooler block 219x gap 20 Vacuum pump 23, 123, 223 Bellows member 25, 125 Elevating device 225 Horizontal moving device 23a, 123a, 223a Elevating block (cross-linking member) 223a Moving block 25a, 125a, 225a Screw rod 26a, 126a, 226a Motor 26b Encoder 27 Limiter Switch (LS) 31 Pressure sensor 33 Temperature sensor 34 Infrared sensor 33a, 34a Processor 35 Controller 36 Display 37, 39 Solenoid valve 40 Safety valve 41-43 Check valve 45 Melt level sensor 51, 52 Solenoid 60 Fixing jig 61 Cylindrical body 61a Circumferential groove 61b of cylindrical body 61 Through hole 61d O-ring 62a, 62b Semi-circular ring-shaped plate 63a, 63b, 64a, 64b Screw 70 Lid 70a Lid 70 Cylindrical body 70b disk-shaped flange 70c screw 70d O-ring 71 rotating shaft 81 support plate 81a ear member 81b annular portion 83 base member

Continued on the front page (72) Inventor Makoto Kamogawa 2612 Yonomiya, Hiratsuka-shi, Kanagawa Prefecture Inside Komatsu Electronic Metals Co., Ltd. 4G077 AA02 BA04 CF10 EG20 EG28 PA01 PA10

Claims (11)

[Claims] 1. A structure in which a cooler for cooling a pulled single crystal provided in a CZ method silicon single crystal pulling apparatus is configured to be movable in a CZ furnace, whereby the defect elimination effect can be adjusted by a dash neck method. How to 2. A cooler for cooling a pulled single crystal provided in a CZ method silicon single crystal pulling apparatus so as to be movable in a CZ furnace while performing a seed drawing operation by a dash neck method. A method of increasing the dislocation elimination effect by the dash neck method by keeping it away from the melt surface. 3. The heat shield as well as the cooler are kept away from the surface of the silicon melt.
The described method. 4. A method for removing a pulling single crystal cooling cooler provided in a CZ method silicon single crystal pulling apparatus in order to enhance the defect elimination effect by the dash neck method. 5. A CZ method silicon single crystal pulling apparatus comprising: a cooler for cooling a pulled single crystal; and an elevating device for elevating the cooler in a CZ furnace, wherein the elevating device is a seed by a dash neck method. An apparatus for pulling a CZ silicon single crystal, wherein the cooler is raised during a drawing operation. 6. A cooler for cooling a pulled single crystal, a lifting / lowering device for raising / lowering the cooler in a CZ furnace, and a heat shield surrounding the single crystal, wherein the CZ is provided in a portable state.
A CZ method silicon single crystal pulling apparatus comprising: a heat shield installed in a furnace, wherein the elevating apparatus is configured to perform the seed drawing operation by a dash neck method while the cooler and the heat A CZ method silicon single crystal pulling apparatus characterized in that a shield is raised. 7. The CZ silicon single crystal pulling apparatus according to claim 6, wherein the cooler and the heat shield are provided with engaging members that engage with each other, and when the cooler is raised, the engaging is performed. A CZ single crystal pulling apparatus, wherein the members are engaged with each other and the heat shield is lifted with the rise of the cooler. 8. A CZ method silicon single crystal pulling apparatus comprising: a crucible capable of storing and raising a silicon melt; and a cooler for cooling the pulled single crystal, wherein the silicon single crystal is pulled from the silicon melt. When performing a seed drawing operation by the dash neck method, the crucible is lowered to perform the seed drawing operation in a state where the silicon melt surface is separated from the cooler, and the CZ method silicon single crystal pulling up. apparatus. 9. A CZ method silicon single unit comprising: a crucible that stores a silicon melt, which can be raised and lowered, a cooler for cooling a single crystal pulled up, and a heat shield surrounding the silicon single crystal pulled up from the silicon melt. A crystal pulling apparatus, wherein when performing a seed drawing operation by the dash neck method, the crucible is lowered to perform the seed drawing operation in a state where the silicon melt surface is separated from the bottom surfaces of the cooler and the heat shield. A CZ method silicon single crystal pulling apparatus. 10. A silicon ingot manufactured by the CZ method single crystal pulling apparatus according to claim 5. 11. A silicon wafer cut from the silicon ingot according to claim 10.