JPS5826095A - Pulling apparatus for single crystal silicon - Google Patents

Abstract

PURPOSE:To prevent the occurrence of dislocation in single crystal Si due to SiO when the single crystal Si is pulled up from a polycrystalline Si melt in an inert gaseous atmosphere, by feeding the atmospheric gas symmetrically with respect to a shaft for pulling up single crystal Si. CONSTITUTION:A seed crystal 15 for single crystal Si is dipped in molten polycrystalline Si 17 in a quartz curcible 2 in a chamber 1 and slowly pulled up with a chain 16 to deposit single crystal Si on the crystal 15 and to pull up it. At this time, a plurality of holes 18 for introducing an inert gas such as Ar are pierced symmetrically with respect to the pulling shaft (chain) in the side wall of the cylindrical protruded part 5 of the chamber 1, and a plurality of holes 19 for exhausting the inert gas are also pierece symmetrically with respect to the pulling shaft. Since the inert gas can be fed symmetrically to the periphery of single crystal Si during pulling, the occurrence of dislocation in the Si due to gaseous SiO can be prevented, and single crystal Si of superior quality can be pulled up.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in single crystal silicon pulling equipment.

Dislocation-free single crystal silicon is used for single crystal silicon substrates used in LSIs. Here, as the diameter (and length) of single crystal silicon increases, the number of degs that can be obtained from single crystal silicon increases, and the cost per t lag can be reduced. As a result, the time it takes to pull a single crystal tends to become longer.

By the way, conventionally, single crystal silicon is mainly manufactured by Czochralski method (CC2 method). In this method, a raw material of polycrystalline silicon is placed in a quarry, the polycrystalline silicon is melted by heating from the surroundings, and the molten material is used as a seed crystal.

It is pulled upward to create single-crystal silicon. At this time, in order to prevent impurities from being contained in the single crystal silicon, it is common practice to introduce an inert gas such as argon into the tank.

Hereinafter, a conventional single crystal silicon pulling apparatus will be explained with reference to FIG.

In the figure, numeral 1 indicates a dianno+- whose upper portion 1m and lower portion 1b are open. Is there 1 quartz rutz in this Champer 1? 2 is placed and the Lu? The outer peripheral surface of 2 is surrounded by a graphite protector 3. A rotatable support rod 4 inserted through the opening of the lower part 1b of the Koki Dang Δ-1 is connected to the bottom surface of the protector S. Moreover, on the outer periphery of the above-mentioned protector S, 1
A cylindrical graphite heater and a cylindrical heat transfer body (not shown) are arranged in this order. Furthermore, (2) the upper part Im of the above-mentioned Dandan Δ-2 is provided with an upper lid 6 having a cylindrical protrusion 5 that matches the opening of the upper part 1s; Through the r-topal f1, a pull channel Δ for temporarily storing the injector after cooling the single crystal silicon is installed.
-I is installed. In addition, the side wall of the cylindrical protrusion 5 of the upper lid has an inert gas inlet 9 as shown in FIG. 2 (t1), and the lower part In addition, an inert gas inlet 11 is provided on the upper side wall of the prudian yΔ-8, and an inert gas inlet 11 is provided on the lower side wall of the prudian/4-8.
Inert gas exhaust ports I2 are provided respectively. Further, a rotatable sol chamber inner lid 13 is provided at the lower part of the inside of the pull damper Δ-8 to close the lower part of the sol chamber 8 when the monocrystalline silicon after being slowly cooled is stored in the pull damper 8. ing. In addition, a measurement window 14 is inserted into the upper lid 6 up to 1 m above the chamber 1.
The cylindrical protrusion 5 of the upper cover 6 is provided with a furnace interior observation window (not shown). Furthermore, a seed crystal 1 is placed at the lower end of the pull chamber 8 into the chamber 1.
A lifting device IC holding 5 is rotatably suspended.

To pull single crystal silicon using the above-mentioned pulling device, an inert gas is introduced into the chamber 1, and the seed crystal z5 at the lower end of the pulling chain 16 is pulled up from a quartz crystal. However, in the conventional pulling device, the quartz silicon 11 in contact with the molten silicon is immersed in the molten silicon 11 in the molten silicon and pulled up. There is a problem in that single crystal silicon becomes dislocated during crystal pulling due to the 1110 gas generated from the 1110 gas.

Therefore, the inventors of Zero Invention conducted various studies on the causes of formation of dislocations during the pulling of single crystal silicon using the above-mentioned conventional pulling apparatus, and as a result, discovered the following.

In other words, in the case of a conventional lifting device (see Fig. 2 (1 m
) and (b), since only one inert gas inlet 9 and one exhaust port 10 are provided,
The inert gas flow is disturbed within Teyanno 4-1 (as shown by the arrow in FIG. 1), and a stagnation layer in which there is almost no inert gas flow forms locally around the single crystal V5 condenser. Near such a stagnant layer of inert gas, 810 powder adheres to the t-yam bar.

Is there 810 powder during pulling? Single crystal V
The dislocation rate of 5pun increases. Moreover, in recent years, the pulling time has tended to become longer as pulled crystals have become larger in diameter and longer, so the above-mentioned tendency is becoming more and more prevalent.

Therefore, 1. Based on the above-mentioned hole drilling results, the present inventor proposed that a plurality of exhaust ports in the lower part of the y-yang Δ- be provided symmetrically around the pulling axis (pulling dean) (2). When inert gas is introduced from the inlet of the 810 gas, it can be flowed symmetrically around the pulling axis around the single crystal silicon being pulled, and the formation of dislocations in the single crystal silicon by the 810 gas can be prevented. We have discovered a pulling device that prevents this problem and makes it possible to pull high-quality single crystal silicon.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4 (a).
This will be explained with reference to (b). However, in FIG. 3, the same members as in FIG. 1 are given the same numbers as in FIG. 1, and their explanations are omitted.

On the side wall of the cylindrical protrusion 5 of the upper lid 6 of the chamber 1, as shown in FIG. . The inert gas inlet 18 is provided within a length of the length between the lower end of the gate pal fr and the upper end of the r-pulp r and the day par 1. The lower part 1bi2 of chamber 1 is shown in Fig. 4 (
As shown in b), a plurality of inert gas exhaust ports 19 are provided symmetrically about the pulling axis.

However, the inert gas exhaust port 19 is not limited to the lower part 1b of the chamber 1, and may be provided within a length of the height of the chamber from the lower end thereof. A plurality of inert gas inlet ports 20 are provided in the upper side wall of the Purudanno motherboard 8 symmetrically with respect to the pulling axis. The inert gas inlet 20 is %
From the top of Sol Champer 8! Redian/4-provided within 1 length of the height. In addition, the inert gas exhaust port I2 at the bottom of the f-rudy damper 8 is! It is provided within the length of the pull damper height from the lower end of the pull chamber 8. The Gluchan/4-8 is used to temporarily store an indentation that has gone through the steps of polycrystalline silicon melting, crystal pulling, and slow cooling in the single-crystal silicon pulling process.

Furthermore, a plurality of measurement windows 14 and furnace observation windows (not shown) on the upper lid 6 of the chamber 1 are also provided around the pulling axis.

According to the above configuration, quartz Ru? When the polycrystalline silicon raw material is put in the inside of 2 (2) and a heater (not shown) is turned on to heat the quartz crystal, the polycrystalline silicon raw material melts and becomes molten silicon 11. In this state, for example, argon gas is The gas is introduced through inert gas inlet ports 18 and 20 formed in the side wall of the cylindrical protrusion 5 of the upper lid 6 of 4-1 and the upper side wall of the glu chamber 8, respectively.

Exhaust air from the bottom 19 of chamber 1. In this case, other inert gas such as helium gas may be supplied instead of argon gas. After this, the quartz ruts surrounded by the protective body 3 are supported by the support rod 4.
While rotating 2, pull up the seed crystal 15 at the lower end of the
Quartz Ruth? When it is immersed in molten silicon z1 in 2 and pulled up while rotating once, single crystal silicon having a predetermined crystal orientation is pulled up. During such a pulling process, since the exhaust ports 19 are arranged symmetrically around the pulling axis, the argon gas flow supplied to the inlets xtt and go is centered around the pulling axis. Symmetrical:: Flow (as shown by the arrow in Figure 3)
, there is no stagnation layer of the aluminium gas flow inside the pulling device.

Therefore, it is possible to reduce the amount of gas adhering to the inside of the pulling device. As a result, single crystal silicon with a low dislocation rate can be pulled.

Fact 1 From the experimental example shown below, it was confirmed that more dislocation-free silicon can be produced than with conventional pulling equipment.

Experimental Example 1 r-) Upper lid C of Dianno Blue-1 of Pulp 1 lower 5cIR
The inert gas inlet 18 is installed in the upper side wall of the cylindrical protrusion 5 at four locations symmetrically about the axis (as shown in FIG. 4(a)), from the center of the chamber 1 in the lower part 1b of the chamber 1. A slit-shaped inert pipe with a width of 20 u is placed at 1 length of the inner diameter at 4 locations symmetrically around the axis (as shown in Figure 4(b)) below the upper end of the % sol chamberer 8. The inert gas inlets 20 are placed on the side wall of the 4css glu chamber at four locations symmetrically around the pull-up axis, and! 55 above the lower end of Ludan Camper 8! An inert gas exhaust port 12 with a diameter of 250 mm was provided at one location on the side wall of the pull chamber.

Furthermore, two rectangular furnace observation windows (not shown) and two measurement windows 14 each having a diameter of 85 u were provided on the upper chamber lid 6 symmetrically about the pulling axis. Here, the in-furnace observation window was provided at the same position as the measurement window 14 when rotated by 90 degrees around the pulling axis. The quartz lugs 2 used had dimensions of 12 inches in diameter and 9 inches in height.

Using the pulling device configured as described above, polycrystalline silicon with a mark of 15 was placed in Rukka and melted.

The inside of the chamber is made into an argon gas reduced pressure atmosphere of 10 torr, and argon gas is introduced from the inert gas inlet Ill, 110, and the argon gas is exhausted from the inert gas exhaust port 1g, and the constant diameter part A piece of single crystal silicon with a diameter of 4 inches was pulled up. During this pulling process, when the flow state of the furnace observation window 810 was observed, it was observed that the 5toif gas flowed symmetrically around the pulling axis and was guided to the exhaust port 19 (see Fig. 3). arrow shown). For this reason, it was confirmed that the adhesion of 8106 powder inside the device after pulling was reduced, and that the manner of adhesion was also symmetrical about the pulling axis.

Furthermore, using the above device, the number of dislocation-free single crystal silicon obtained in 120 hours of continuous operation was investigated and compared with the case using a conventional device. When the average of 10 operations was calculated, it was found that when using conventional equipment, 1 operation (120 hours)
Only 6.2 dislocation-free single-crystalline silicon pieces were obtained per run, but when the above-mentioned apparatus was used, 8.4 dislocation-free single-crystalline silicon pieces could be obtained per run.

Experimental Example 2 Inert gas inlet ports 18' were placed on the upper side wall of the cylindrical protrusion 5 of the upper cover σ of the chamberer L in the lower part 53 of the dirt pulp 1 at 20 locations symmetrically about the lifting axis (Fig. 5 (Maro)). (Illustrated)
Inert gas exhaust ports 19' with a diameter of 30 m11 are installed at 12 locations (5th
Figure (b1 shown) and the lower part 4 from the upper end of the pull champer 8
Inert gas inlets 20 were provided at 20 locations symmetrically about the pulling axis on the side wall of the glue chamber in the wound. Here, single-crystal silicon was pulled under the same conditions as in Experimental Example 1 except for an argon gas atmosphere at normal pressure.

Using the pulling device with the above configuration, we investigated the number of dislocation-free single crystal silicon that could be obtained in 120 hours of continuous operation.
A comparison was made with the case using a conventional device. The average of 10 operations was calculated.

5 per % (120 hours) using conventional equipment
．． Although only one dislocation-free single crystal silicon was obtained,
When the above-mentioned apparatus was used, 7.2 dislocation-free single crystal silicon could be obtained.

As is clear from Experimental Example 1.2 above, when the apparatus of the present invention is used, the flow of alponic gas becomes symmetrical about the pulling axis, so compared to the case where the conventional apparatus is used, It can be seen that the number of dislocation-free single-crystal V9 capacitors obtained in one operation increases.

As detailed above, according to the present invention, the flow of the inert gas becomes symmetrical about the pulling axis, so dislocation formation in the single crystal silicon is suppressed, and the diameter of the pulled single crystal silicon is increased. It is possible to provide a vine pulling apparatus for producing single crystal silicon that can sufficiently respond to the trend of longer lengths and longer pulling times as a result.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a conventional single crystal silicon pulling device;
Fig. 2(a) is a cross-sectional view of the person in Fig. 1, Fig. 2(b) is a sectional view taken along line B-B of Fig. 1, and Fig. 3 is a cross-sectional view showing the single-crystal silicon pulling apparatus of the present invention. , Figure 4 (1) is C-C in Figure 3.
The cross-sectional view, FIG. 4(b) is a cross-sectional view taken along line DD in FIG. 3, and other forms of defects corresponding to FIGS. Active gas inlet. It is a sectional view showing an exhaust port. 1... Chan Δ-12... Quartz rutz &, l... Graphite protector, 4... Support rod, 6... Upper lid, 8...
Solchan Δ-, 9, 11, 18, 111', 20・
... Inert gas introduction 0.10.12 , 19 , 19
'--Inert gas exhaust port, I4...Measurement window, 15
... Seed crystal, 16... Pull-up dean, 17... Molten silicon O Applicant's agent Patent attorney Takehiko Suzue II Figure 2 (a) (b)! 13m Figure 4 19 511 (a) (b) 19゛

Claims (1)

[Claims] Is there a quartz glass bolt inside the damper? Place it. In an apparatus for producing single-crystal silicon by pulling the molten νRipun in the melt 1 under an inert gas atmosphere below normal pressure, an inert gas inlet is provided at a desired position above the damper, and an inert gas inlet is provided near the bottom of the chamber. 1. A single-crystal silicon pulling apparatus characterized in that a plurality of inert gas exhaust ports are arranged symmetrically about a pulling axis.