KR20130063584A - Exhausting system for single crystal grower - Google Patents

Abstract

PURPOSE: An exhausting system for a single crystal growing apparatus is provided to prevent the backflow of impurities by using a concavo-convex part, a funnel, and a mesh part used as a flow path resistance. CONSTITUTION: An exhaust pipe(150) discharges the gas of a chamber. A resistance unit is formed in the exhaust pipe and filters impurities in the backflow of the impurities. The resistance unit includes a concavo-convex part(210), a mesh part(220), and a funnel(230). The mesh part crosses the inner surface of the exhaust pipe. The funnel is attachable/detachably to/from the inlet(151) of the exhaust pipe. A detection unit includes an inspection plate(300) vertical to the flow direction of the exhaust gas in the inlet of the exhaust pipe.

Description

Exhaust system of single crystal growth unit {EXHAUSTING SYSTEM FOR SINGLE CRYSTAL GROWER}

The present invention relates to an exhaust system of a single crystal growth apparatus capable of detecting impurities as well as reducing backflow of impurities contained in gas from the exhaust pipe to the chamber.

Generally, for the production of silicon wafers, monocrystalline silicon is grown in an ingot shape. Czochralski (CZ) method can be applied to grow an ingot.

In the single crystal ingot growing process, solid silicon is put into a crucible, and then heat is applied to form a liquid phase, which is then grown into a single crystal ingot. At this time, the ingot is grown in a vacuum state.

Meanwhile, during the growth of the single crystal ingot, an impurity such as an oxide film material, which is emitted from a high-temperature silicon melt by using an inert gas such as argon (Ar), is discharged to the inside of the single- I have to.

All of these impurities are not discharged outside the single crystal growth apparatus, but are deposited inside the single crystal growth apparatus, thereby causing loss in single crystal growth.

Therefore, in order to remove the impurities adhering to the inside of the single crystal growth apparatus after the completion of the single crystal growth, the operator carries out cleaning by manual operation or cleaning by an automated chamber cleaning apparatus.

The ingot is discharged repeatedly for the ingot growing operation or the chamber is opened to inject the solid silicon, whereby impurities in the outside air are introduced into the chamber.

However, in order to grow the ingot, the inside of the chamber is made to be in a vacuum state. When the vacuum pump provided on the side of the exhaust pipe connected to the chamber is operated, the impurities inside the chamber escape like the exhaust gas.

The exhaust system of the conventional single crystal growth apparatus as described above may be unstable when the vacuum pump is initially turned on, so that the exhaust gas may flow back from the exhaust pipe, or the vacuum pump may be operated for a certain time to reach the vacuum state. When there is no pressure difference inside the chamber and the exhaust pipe, impurities contained in the exhaust gas are sporadically flowed back by the molecular flow, and when the exhaust gas is larger than the capacity due to the limited capacity of the vacuum pump, the exhaust gas is similarly exhausted. Impurities contained in are reversed in the molecular flow state.

In addition, it is difficult to detect the reverse flow of the impurities flowing into the chamber, and it is difficult to detect when impurities which are not visible are introduced into the chamber due to backflow of the impurities flowing through the molecules.

Therefore, due to the reverse flow of impurities flowing into the chamber, the impurities act as a crystal loss in the growth of the ingot in the chamber, thereby increasing the defect rate of the silicon wafer and deteriorating the quality of the silicon wafer. Further, There is a problem that the efficiency of the cleaning is lowered due to the progress of the additional cleaning work.

The present invention has been made to solve the above problems of the prior art, and an object of the present invention is to provide an exhaust system of a single crystal growth apparatus that can reduce the backflow of impurities flowing into the chamber along the exhaust pipe.

It is also an object of the present invention to provide an exhaust system of a single crystal growth apparatus capable of detecting impurities backflowed by molecular flow along the exhaust pipe to the chamber.

The present invention relates to a process for producing a crucible, comprising: a chamber having a crucible grown as an ingot; An exhaust pipe for exhausting gas inside the chamber; A vacuum pump connected to the exhaust pipe, for evacuating the inside of the chamber; And resistance means provided in the exhaust pipe and filtering impurities during the reverse flow of the impurities.

Further, in the present invention, the exhaust pipe may be connected to a lower portion of the chamber, and the resistance means may be provided at an inlet of an exhaust pipe connected to the chamber.

Further, in the present invention, the resistance means may be a plurality of concave-convex portions formed along the inner circumferential surface of the inlet of the exhaust pipe.

Preferably, the concavo-convex portion may have a triangular cross section cut in the gas exhaust direction.

Further, in the present invention, the resistance means may include a mesh portion disposed to cross the inner circumferential surface of the exhaust pipe.

Preferably, the mesh portion may have a hole size of 500 mu m or less.

Further, in the present invention, the resistance means may include a funnel mounted at an inlet of the exhaust pipe, the diameter of which narrows toward the exhaust direction of the gas.

Preferably, the funnel may be provided with a concave / convex portion on an outer circumferential surface facing the inner circumferential surface of the exhaust pipe.

Preferably, the funnel may be provided with a plurality of grooves for guiding the exhaust flow of the gas on the upper surface thereof.

Further, in the present invention, it may further comprise a detection plate mounted to be erected in the flow direction of the exhaust gas to the pipe inlet, and to which the impurities can be adhered.

Preferably, the detection plate may be a silicon wafer.

According to another aspect of the present invention, there is provided a method of manufacturing a crucible, An exhaust pipe for exhausting gas inside the chamber; A vacuum pump connected to the exhaust pipe, for evacuating the inside of the chamber; And a detection plate mounted on the inlet of the exhaust pipe to stand in the flow direction of the gas and to which impurities may be attached.

Further, in the present invention, the apparatus may further include a funnel which is seated at the inlet of the exhaust pipe, the detection plate is fixed to the upper surface, and the diameter becomes narrower toward the exhaust direction of the gas.

Preferably, the funnel may be provided with a concave / convex portion on an outer circumferential surface facing the inner circumferential surface of the exhaust pipe.

Preferably, the funnel may be provided with a pair of grooves on the upper surface thereof to which the detection plate can be fitted.

Further, in the present invention, the detection plate may be a silicon wafer.

Further, in the present invention, it may further include a plurality of concave-convex parts formed along the inner circumferential surface of the inlet of the exhaust pipe.

Preferably, the concavo-convex portion may have a triangular cross section cut in the gas exhaust direction.

Further, in the present invention, it may further comprise a mesh portion provided to cross the inner circumferential surface of the exhaust pipe.

Preferably, the mesh portion may have a hole size of 500 mu m or less.

The exhaust system of the single crystal growth apparatus according to the present invention is provided with an uneven portion, a funnel, and a mesh portion that act as a flow path resistance to the flow in the reverse flow direction on the exhaust pipe, thereby preventing backflow of impurities flowing through the molecular flow and filtering impurities. In this case, it is possible to reduce the crystal loss during ingot growth and to improve the quality of the silicon wafer made by the ingot.

In addition, in the exhaust system of the single crystal growth apparatus according to the present invention, since the test plate is provided at the inlet of the exhaust pipe in the flow direction of the exhaust gas, the impurities flowing in the molecule may be adsorbed on the test plate and detected. Through not only to recognize the reverse flow of impurities flowing through the molecule, but also by analyzing the impurities there is an advantage that can analyze the cause of the crystal loss during ingot growth.

1 is a schematic view showing an example of a single crystal growing apparatus according to the present invention;
Figure 2 is a plan view showing the lower chamber of the single crystal growth apparatus according to the present invention.
Figure 3 is a side cross-sectional view showing the main part of the exhaust system of the single crystal growth apparatus according to the present invention.
Fig. 4 is a view showing an example of the exhaust pipe applied to Fig.
5 is a cross-sectional perspective view illustrating an example of a funnel applied to FIG. 3;
FIG. 6 is a plan view showing an example of a funnel applied to FIG. 3; FIG.
7 is a view showing an impurity detection state when applying the exhaust system of the single crystal growth apparatus according to the present invention.

Hereinafter, the present embodiment will be described in detail with reference to the accompanying drawings. It should be understood, however, that the scope of the inventive concept of the present embodiment can be determined from the matters disclosed in the present embodiment, and the spirit of the present invention possessed by the present embodiment is not limited to the embodiments in which addition, Variations.

FIG. 1 is a schematic view showing an example of a single crystal growing apparatus according to the present invention, and FIG. 2 is a plan view showing a lower portion of a chamber of a single crystal growing apparatus according to the present invention.

A single crystal growth apparatus according to the present invention includes a chamber 110 in which an ingot is grown, a crucible 130 provided in the chamber 110, a heater 140 for heating the crucible, (Not shown) for lifting the cable, which is provided on the upper portion of the chamber 110, for lifting up the cable, and an exhaust pipe 150 provided below the chamber 110 to exhaust the exhaust gas. A vacuum pump 160 connected to the exhaust pipe 150 for evacuating the inside of the chamber 110 and resistive means for filtering impurities back flowing into the molecular flow from the exhaust pipe 150; (Not shown) for detecting impurities that flow back to the molecular flow from the gas flow channel (not shown).

The chamber 110 provides a space in which predetermined processes for growing a single crystal ingot for a silicon wafer used as an electronic component material such as a semiconductor are performed.

At this time, a Czochralski (CZ) method may be employed in which a single crystal seed crystal is immersed in molten silicon and a crystal is grown while slowly pulling it up, as a method of growing a silicon single crystal ingot (IG) .

According to this method, after a necking process for growing elongated crystals from a seed crystal, a process of growing a crystal in a radial direction to make a target diameter is performed, and then a crystal having a constant diameter After the body growing process, the body is grown by a body growing process, the diameter of the crystal is gradually decreased after progressing the body growth, and finally the tiling process is performed to separate the silicon from the molten silicon. It grows.

The crucible 130 is provided in the chamber 110 to contain the silicon solution, and may be made of quartz. Of course, a crucible support (not shown) made of graphite can be provided outside the crucible 130 to support the crucible 130. The crucible 130 is rotated by the driving means (not shown) to rotate the crucible 130. The crucible 130 is rotated by the driving means (not shown) And allowing the solid and liquid interfaces to maintain the same height while moving up and down.

The heater 140 is provided on the inner wall of the chamber 110 to heat the crucible 130. The heater 140 may be formed in a cylindrical shape to surround the crucible support and a power supply line 141 for supplying power to the lower side is connected. In addition, a radiator (not shown) may be installed on the inner wall of the chamber 110 to prevent the heat of the heater 140 from being discharged through the wall of the chamber 110. At this time, the heater melts the high-purity polycrystalline silicon mass loaded in the crucible 130 to produce a silicon solution.

The lifting means may be installed on the upper part of the chamber 110 so as to lift up the cable (not shown), and may include a seed crystal provided under the cable. In addition, a heat shield 120 may further be provided in the chamber 110 to block heat from the silicon melt during growth of the single crystal ingot.

Therefore, the seed crystal grows in contact with the silicon solution in the crucible 130 and is pulled up to grow a single crystal ingot. The lifting means lifts up the cable and lifts the single crystal ingot while rotating, The crucible 130 can be rotated while being rotated about the same axis as the rotation axis 131 of the crucible 130 in the rotation direction or the opposite direction of the crucible 130.

The exhaust pipe 150 is connected to the lower portion of the chamber 110 to form a flow path for discharging the gas inside the chamber 110. At this time, the exhaust pipe 150 exhausts the outside air introduced into the chamber 110 before the ingot is grown, and also exhausts the gas generated from the melt even when the ingot is grown.

The vacuum pump 160 is connected to the exhaust pipe 150. The vacuum pump 160 is operated before the ingot is grown to make the inside of the chamber 110 vacuum, .

The resistance means is provided to reduce backflow of exhaust gas from the exhaust pipe 150 to the chamber 110 and further to filter impurities that flow back into the molecular flow. The exhaust pipe 150 is connected to the chamber 110, that is, the inlet 151 of the exhaust pipe 150, and a detailed configuration will be described below. At this time, the resistance means can reduce the reverse flow due to the molecular flow of the exhaust gas, and the molecular flow generally occurs at a high vacuum region of 10 to 3 torr or less in the atmospheric pressure, so that the gas flow is not performed from the high pressure to the low pressure, .

The detection means is provided at the inlet 151 of the exhaust pipe 150 to detect impurities that flow back into the molecular flow, and a detailed configuration will be described below.

3 to 6 is a view showing the main part of the exhaust system of the single crystal growth apparatus according to the present invention.

The resistance means includes a recessed portion 210 provided in the exhaust pipe 150, a mesh portion 220 provided in the exhaust pipe 150, A funnel 230 may be included.

A plurality of the concave and convex portions 210 may be provided in a part of an inner circumferential surface of the inlet 151 of the exhaust pipe 150 and may act as a resistance against backflowing impurities. At this time, the concave-convex portion 210 may be formed in a triangular shape in cross section cut in the flow direction of the exhaust gas, and may be formed in various shapes and arrangements. In addition, It is preferable to be formed to collide perpendicularly with the flow.

The mesh portion 220 is installed to cross the inner circumferential surface of the exhaust pipe 150 and is located below the concave and convex portion 210. At this time, the mesh part 220 filters the impurities which flow backward, and the size of the lattice may be formed to be less than 500 탆 so as to filter the impurities, and it is not preferable that the mesh part 220 is formed to be excessively small.

The funnel 230 may be detachably mounted on the inlet 151 of the exhaust pipe 150 or integrally formed with the inlet 151 of the exhaust pipe 150 and may have a smaller diameter It can act as a resistance against backflowing impurities. The concave and convex portion 231 of the funnel 230 is also provided on the outer peripheral surface of the funnel 230 opposite to the concave and convex portion 210 of the exhaust pipe 150, And may be formed in various shapes and arrangements. In addition, the upper surface of the funnel 230 may be provided with a plurality of grooves 232 for guiding the discharge of the exhaust gas. Hereinafter, the grooves 232 may be utilized for mounting the detecting means. A pair may be provided in a direction opposite to each other. The inner surface of the funnel 230 may include a helical groove for guiding the flow direction of the exhaust gas, a mesh portion for filtering impurities, and the like, but will not be described here.

The detection means may include an inspection plate 300 erected in the flow direction of the exhaust gas to the inlet 151 of the exhaust pipe 150. The inspection plate 300 can be mounted on the grooves 232 of the funnel 230 and installed to stand up in the flow direction of the exhaust gas. At this time, the inspection plate 300 is made of a material capable of adsorbing impurities, and a silicon wafer having a property of easily observing impurities when exposed to light can be used.

Looking at the operating state of the exhaust system of the single crystal growth apparatus configured as described above with reference to Figures 1 and 3 as follows.

The ingot grown inside the chamber 110 is taken out and external air containing impurities flows into the chamber 110 even if the interior of the chamber 110 is cleaned.

When the vacuum pump 160 is operated to make the interior of the chamber 110 vacuum, an incomplete operation during the initial operation of the vacuum pump 160 causes the exhaust pipe 150 to flow into the chamber 110 The exhaust gas can flow backward. When the vacuum pump 160 operates stably and the inside of the chamber 110 reaches the vacuum state, the flow of the exhaust gas flowing from the high pressure to the low pressure is irregularly progressed, so that the exhaust pipe 150 The exhaust gas can flow back into the chamber 110. Also, when the capacity of the vacuum pump 160 is exceeded, the exhaust gas may flow back into the chamber 110 from the exhaust pipe 150. At this time, the exhaust gas flowing into the chamber 110 from the exhaust pipe 150 is regarded as flowing backward by the molecular flow, and the impurities also travel to the molecular flow due to the reverse flow of the exhaust gas due to the molecular flow.

When the impurities flow back into the molecular flow along the exhaust pipe 150, the impurities rising along the exhaust pipe 150 are partially filtered while passing through the mesh unit 220.

When the impurities passing through the mesh part 220 rise along the inner circumferential surface of the exhaust pipe 150, the impurities are further filtered by the irregularities 210 of the exhaust pipe 150, The direction of flow may be changed.

When the impurities passing through the mesh portion 220 are lifted along the center portion of the exhaust pipe 150, the impurities impinge on the outer surface of the funnel 230 and the irregularities 231 provided thereon, And the flow direction is changed again in the exhaust direction.

However, the impurities which are not filtered by the mesh portion 220, the concave and convex portions 210 and the funnel 230 are flowed back into the chamber 110 through the center of the funnel 230 . At this time, the impurities back flowing into the chamber 110 are adsorbed on the inspection plate 300 while passing along the inspection plate 300.

7 is a view showing an impurity detection state when applying the exhaust system of the single crystal growth apparatus according to the present invention.

Accordingly, the above process is performed until the ingot growth is completed. When the ingot growth is completed, the inspection plate 300 is taken out, and then the inspection plate 300 is irradiated with light as shown in FIG. 7 It is possible to identify the cause of the crystal loss of the ingot on the basis of the amount and kind of the impurities, and furthermore, the control condition can be changed for better quality in a later ingot growing step.

According to the present invention, even if impurities flowing in a molecule flow back to the chamber from the exhaust pipe, the reverse flow of the impurities flowing in the molecular flow is reduced by sequentially filtering by the mesh portion, the concave-convex portion and the funnel, And the quality of the silicon wafer produced by such an ingot can be improved.

Further, according to the present invention, impurities flowing through the exhaust pipe are adsorbed on the inspection plate even if the impurities flow from the exhaust pipe back into the chamber, so that the reverse flow of the impurities flowing in the molecules can be sensed. Further, On the basis of this, it is possible to analyze the cause of the crystal loss of the ingot, and it is possible to easily change the control element in the subsequent process, thereby improving the quality.

150: exhaust pipe 210: concave /
220: mesh part 230: funnel
300: Inspection board

Claims (20)

A chamber having a crucible grown as an ingot;
An exhaust pipe for exhausting gas inside the chamber;
A vacuum pump connected to the exhaust pipe, for evacuating the inside of the chamber; And
Exhaust system provided in the exhaust pipe, the resistance means for filtering impurities during the back flow of impurities; exhaust system of a single crystal growth apparatus comprising a. The method of claim 1,
Wherein the exhaust pipe is connected to a lower portion of the chamber,
The resistance means is an exhaust system of the single crystal growth apparatus provided in the inlet of the exhaust pipe connected to the chamber. The method of claim 2,
And the resistance means is a plurality of uneven parts formed along the inner circumferential surface of the inlet of the exhaust pipe. The method of claim 3,
The uneven part is an exhaust system of a single crystal growth apparatus having a triangular cross section cut in the gas exhaust direction. The method of claim 2,
And the resistance means comprises a mesh portion provided to cross the inner circumferential surface of the exhaust pipe. The method of claim 5,
The mesh portion exhaust system of the single crystal growth apparatus having a hole size of 500㎛ or less. The method according to any one of claims 2 to 6,
And the resistance means is mounted to an inlet of the exhaust pipe, and includes a funnel that narrows in diameter toward the exhaust direction of the gas. The method of claim 7, wherein
The funnel exhaust system of the single crystal growth apparatus is provided with irregularities on the outer peripheral surface facing the inner peripheral surface of the exhaust pipe. The method of claim 7, wherein
The funnel exhaust system of the single crystal growth apparatus having a plurality of grooves for guiding the exhaust flow of the gas on the upper surface. 10. The method of claim 9,
And a detection plate mounted at the inlet of the pipe to stand in the flow direction of the exhaust gas and to which impurities may be attached. The method of claim 10,
And the detection plate is a silicon wafer. A chamber having a crucible grown as an ingot;
An exhaust pipe for exhausting gas inside the chamber;
A vacuum pump connected to the exhaust pipe, for evacuating the inside of the chamber; And
And a detection plate mounted on the inlet of the exhaust pipe so as to stand in the flow direction of the gas and to which impurities may be attached. The method of claim 12,
And a funnel seated at an inlet of the exhaust pipe, the detection plate being fixed to an upper surface thereof, and having a diameter narrowing toward the exhaust direction of the gas. The method of claim 13,
The funnel exhaust system of the single crystal growth apparatus is provided with irregularities on the outer peripheral surface facing the inner peripheral surface of the exhaust pipe. The method of claim 13,
The funnel is exhaust system of a single crystal growth apparatus having a pair of grooves in which the detection plate is fitted on the upper surface. 16. The method according to any one of claims 12 to 15,
And the detection plate is a silicon wafer. 17. The method of claim 16,
The exhaust system of the single crystal growth apparatus further comprises; a plurality of uneven parts formed along the inner peripheral surface of the inlet of the exhaust pipe 18. The method of claim 17,
The uneven part is an exhaust system of a single crystal growth apparatus having a triangular cross section cut in the gas exhaust direction. 17. The method of claim 16,
And a mesh unit disposed to cross the inner circumferential surface of the exhaust pipe. 20. The method of claim 19,
The mesh portion exhaust system of the single crystal growth apparatus having a hole size of 500㎛ or less.

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