JP2631591B2 - Semiconductor single crystal manufacturing method and manufacturing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor single crystal manufacturing apparatus for manufacturing a homogeneous semiconductor single crystal from a raw material melt in a crucible by providing a new flow path for an inert gas introduced into the apparatus. About.

[0002]

2. Description of the Related Art For growing a semiconductor single crystal, a CZ (Czochralski pulling) method for growing a columnar crystal from a raw material melt in a crucible is widely used.

Usually, in growing a semiconductor single crystal, a crucible is installed in a chamber evacuated to a predetermined vacuum to maintain a high quality of the grown single crystal. A method of growing a crystal while pulling the crystal from the crystal is used.

For example, as shown in FIG. 5, in a conventional semiconductor single crystal growing apparatus, a raw material 3 housed in a quartz crucible 2 installed in a chamber 1 kept under reduced pressure is heated by a heater 4.
Then, the seed crystal attached to the pulling shaft 5 is immersed in the melt, and is pulled upward while rotating, so that the single crystal 6 grows. Here, a pedestal (crucible support) 7 is provided in the heater 4.
The quartz crucible 2 is further mounted in the graphite crucible 9 supported by the crucible receiver 8 mounted on the quartz crucible 2, and for example, a silicon raw material is melted in the quartz crucible 2 and held as a raw material melt. Here, reference numeral 10 denotes a heat retaining cylinder.

In such an apparatus, there is a problem that a high-temperature gas containing silicon oxide (SiO) reaches the inner wall of the chamber or the pulling shaft, and is cooled, condensed and adhered. If such deposits fall and mix into the melt, dislocations may occur in the grown single crystal, which may cause quality degradation.

In order to solve this problem, in order to discharge silicon oxide evaporated from the melt surface, an inert gas such as argon gas is introduced through a gas inlet (not shown) provided in the upper portion of the chamber 1. The gas is introduced, passes from the region near the raw material melt in the crucible, passes between the heater 4 and the graphite crucible 9, and between the heater 4 and the heat retaining cylinder 10, and goes to the lower part of the chamber. There has been proposed a structure in which the air is discharged to the air.

However, even in such a configuration, since the lower portion of the heater and the periphery of the exhaust port, which are still the lower portion of the chamber, are in a low temperature range, a high temperature gas containing argon gas and silicon oxide comes in contact with a low temperature object. As a result, there is a problem that the powder is easily deposited and deposited as a powder.

[0008] Most furnace products such as heaters and heat retaining cylinders are made of high-purity carbon products. After pulling them up and examining their surfaces, it was found that amorphous adhered below the chamber and silicon carbon Is confirmed. Then, as the number of times of pulling increases, the contamination of carbon with silicon-based material is remarkably accumulated.

The infiltration of silicon into carbon and the formation of SiC on the carbon surface cause deterioration of furnace components, and when the degree of deterioration is severe, the furnace components are bonded to each other, making division impossible, making handling difficult. There was a problem of making things. In particular, in-furnace products having different lifespans for use are often adhered to each other, so that their exchangeability is often impaired.

As described above, not only does the life of the in-furnace product be shortened, but also the quality is changed by changing the in-furnace temperature distribution and affecting the heat history of the grown single crystal. It is highly possible that

In the latter half of the growing process, the amorphous material deposited and deposited on the upper end of the quartz crucible may fall off in the melt in some cases and become dislocations by being attached to the crystal, thereby deteriorating the quality of the pulled crystal. Was the cause. In addition, as the size of the apparatus increases, it is inevitable that the surface area of the melt increases, so that the evaporation of silicon oxide further increases, and the risk of dislocations increases. Therefore, even if the silicon oxide is efficiently discharged by controlling the gas flow, it is probable that the life of the in-furnace products is shortened by that much, and at present the fundamental solution has not been reached.

[0012]

As described above, in the conventional method and apparatus, since the lower portion of the heater, which is the lower portion of the chamber, and the periphery of the exhaust port are in a low temperature range, they contain an inert gas and silicon oxide. High-temperature gas comes into contact with low-temperature objects to form powder and adheres and accumulates.This shortens the life of the furnace and reduces the life of the furnace. There is also a problem that dislocation is caused by the attachment, and the quality of the pulled crystal is deteriorated.

The present invention has been made in view of the above circumstances, and provides a method and apparatus for pulling a semiconductor single crystal capable of preventing deterioration of furnace components and obtaining a high-quality single crystal for a long period of time. Aim.

[0014]

SUMMARY OF THE INVENTION Accordingly, the method of the present invention involves simultaneously disabling the crucible and the heater in the chamber from below and / or between the crucible and the heat retaining cylinder from below, and from above along the pulled single crystal. Activated gas is introduced and pulled out while passing out of the chamber through the upper part of the heat retaining cylinder.

In the apparatus of the present invention, an inert gas is simultaneously introduced from below the space between the crucible and the heater and / or between the crucible and the heat retaining cylinder in the chamber and from above along the pulled single crystal. Means are provided so that the inert gas is pulled out while passing out of the chamber through the upper part of the heat retaining cylinder.

[0016]

According to the above construction, the silicon oxide gas is prevented from flowing under the crucible and the heater or between the heater and the heat retaining cylinder by the inert gas, and the silicon oxide gas is efficiently guided to the exhaust port, and It is possible to prevent the in-furnace product from deteriorating due to adhesion of water.

Here, in the furnace, it is necessary to appropriately partition the furnace space by furnace products so that the argon gas introduced from below is not immediately discharged to the exhaust port. Preferably, a plurality of gas inlets are arranged at a position substantially below the main heater. As a result, the fresh inert gas introduced from the base chamber creates a flow that rises from below the heater toward the upper end portion, flows from above on the uppermost heat shield ring, and passes through the region near the melt. It merges with the inert gas flow, descends through the space between the chamber and the heat retaining cylinder, and is guided to the outside of the furnace from the exhaust port on the side wall of the chamber. Most of the silicon oxide gas is discharged outside the heat retaining cylinder by this gas flow, so that the heater, the carbon electrode, and the like can be prevented from being deteriorated by the permeation of silicon.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

A single crystal manufacturing apparatus according to a first embodiment of the present invention has a base plate at the bottom of a chamber 1 constituting a single crystal manufacturing apparatus main body, as shown in a sectional view of FIG. A total of eight argon gas inlets 13 are provided, one for every 45 degrees, along the position directly below the heater 4 of the eleventh heater. The argon gas introduced from the argon gas inlet 13 is supplied to the crucible, the heater 6, To form an ascending flow, and together with the argon gas introduced from the upper part of the chamber, a gas outlet 12 provided on the side of the base plate from the top end of the heater 4 through the space between the heat retaining cylinder 10 and the chamber side wall 15. From the chamber to the outside of the chamber.

The other parts are formed in the same manner as the conventional apparatus shown in FIG. 5, and the single crystal raw material 3 housed in the quartz crucible 2 in the chamber 1 kept under reduced pressure is heated and melted by the heater 4. Then, the seed crystal attached to the pulling shaft 5 is immersed in the melt, and is pulled upward while rotating the seed crystal to grow the single crystal 6. In FIG. 1, reference numeral 10 denotes a heat retaining cylinder, the lower portion of which is fixed to the base plate 11 so as to be in close contact therewith. After flowing upward, the gas flows down the outside of the heat-insulating cylinder together with the argon gas introduced from the upper part of the chamber so as to prevent the water from flowing outside the heat-insulating cylinder. . Further, inside the heater 4, the quartz crucible 2 is further mounted in the graphite crucible 9 supported by the crucible receiver 8 mounted on the pedestal (crucible support) 7, and the silicon raw material is melted inside the quartz crucible 2. It is held as a raw material melt. Reference numeral 14 denotes an electrode of the heater.

In such an apparatus, a high-temperature gas containing silicon oxide (SiO) is prevented from flowing into a low-temperature region between the crucible and the heater and between the heater and the heat retaining cylinder. To the outside of the chamber.

Next, a method of growing a silicon single crystal using this single crystal manufacturing apparatus will be described.

First, the chamber 1 is evacuated to 10 ⁻²
~ ^-3 Torr.

Then, argon gas was introduced at a rate of 20 l / min from the argon gas inlet 13 and a gas inlet (not shown) at the top of the chamber.
The heater 4 for heating the internal crucible is turned on to obtain a raw material melt.

Then, a seed crystal is immersed in the raw material melt and pulled up at a predetermined speed by a pulling section (not shown) to grow a single crystal.

According to this apparatus, the high-temperature gas containing silicon oxide (SiO) is cooled by the flow of the gas flowing into the chamber 1 from the argon gas inlet 13 provided in the base plate 11. Since it reaches the region and is guided upwards in a gaseous state without adhering, it does not cause deterioration of furnace components or foreign substances mixed into the raw material melt, and has few crystal defects for a long time Good crystals can be obtained.

Further, the present invention is not limited to the above-described embodiment, but can be applied to various application examples, for example, for growing a single crystal other than silicon.

Next, as a second embodiment of the present invention, as shown in FIG. 3, when the exhaust port 22 is formed at the bottom of the base plate 11, the lower end of the heat retaining cylinder 20 is deformed inward to form the exhaust port 22. And the argon gas inlet 13 are connected to the heat insulating cylinder 20
And the gas flow may be satisfactorily raised inside the heat insulation cylinder and lowered outside, and guided to the exhaust port 22.

In addition to the structure of the first embodiment, as shown in FIG. 4, an argon gas may be supplied at about 20 l / min from above by attaching a cover cylinder 21 so that the gas near the crystal is rectified. The grown crystal can be prevented from being contaminated, and the quality can be further improved. Otherwise, the configuration may be exactly the same as that of the first embodiment.

[0030]

As described above, according to the present invention, the inert gas introduced from below the chamber forms a flow which rises from below the heater toward the upper end,
For example, the adhesion of silicon oxide can extend the life of a consumable in a carbon furnace, which has been a consumable having a short life, and can improve the production yield of a pulled single crystal.

[Brief description of the drawings]

FIG. 1 is a sectional view of a single crystal manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the single crystal manufacturing apparatus according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a main part of a single crystal manufacturing apparatus according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a single crystal manufacturing apparatus according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional single crystal manufacturing apparatus.

[Explanation of symbols]

 Reference Signs List 1 chamber 2 quartz crucible 3 melt 4 heater 5 pulling shaft 6 single crystal 7 pedestal 8 crucible receiver 9 graphite crucible 10 heat insulating cylinder 11 base plate 12 exhaust port 13 argon gas inlet 14 electrode 15 chamber side wall 16 heat shield ring 20 heat insulating cylinder 21 Cover cylinder

Claims (2)

(57) [Claims] 1. A crucible to be filled with a raw material, a cylindrical heater around the crucible, and a heat insulating cylinder surrounding the heater are installed in a chamber, and the raw material in the crucible is melted by the heater. A method for producing a semiconductor single crystal, comprising: a melt forming step of forming a melt; and a pulling step of dipping a seed crystal in a raw material melt in the crucible to pull up a single crystal, wherein the pulling step is performed by using the chamber An inert gas is introduced simultaneously from below between the crucible and the heater and / or between the crucible and the heat retaining cylinder from above and further along the pulled single crystal from above, and passes above the heat retaining cylinder into the chamber. A method for producing a semiconductor single crystal, comprising a step of pulling out while pulling out. 2. A crucible for filling a raw material, a cylindrical heating heater installed to surround a periphery of the crucible, and melting a raw material in the crucible to form a raw material melt; A semiconductor single crystal manufacturing apparatus comprising: a chamber having an insulated cylinder surrounding it; and a pull-up unit for dipping a seed crystal in a raw material melt in the crucible to pull up a single crystal, wherein the crucible in the chamber and the crucible From below between the heater and or between the crucible and the heat retaining cylinder,
A semiconductor single crystal manufacturing device comprising an argon gas introduction means configured to simultaneously introduce an inert gas from above along the pulled single crystal and to lead out of the chamber through above the heat retaining cylinder. apparatus.