KR100777336B1 - Apparatus for manufacturing silicon single crystal ingot - Google Patents

Abstract

An apparatus for manufacturing a silicon single crystal ingot is provided to minimize loss of a dopant by doping efficiently a low melting point dopant into a silicon melt. A quartz crucible(110) is formed to receive a silicon melt. A heating unit(120) supplies a heating source to the silicon melt. A sidewall insulating member(130) is formed to surround the heating unit in order to reduce thermal loss to a lateral surface. A heat shielding member(140) is installed on the heating unit in order to reduce the thermal loss to an upper part. A lifting unit(300) dips a silicon seed crystal into the silicon melt or lifts the silicon seed crystal from the silicon melt. A position control unit controls the height of the quartz crucible. A dopant supply plate(180) includes a supporting groove coupled with the heat shielding member, at least one dopant reception groove for receiving a low melting point, and a groove covering net for supporting the low-melting point dopant.

Description

Apparatus for manufacturing silicon single crystal ingot

1 is a schematic diagram of an apparatus for producing a silicon single crystal ingot according to the present invention.

FIG. 2 is a perspective view illustrating a bottom surface of the dopant supply plate in FIG. 1.

3 is a perspective view illustrating a top surface of the dopant supply plate in FIG. 1.

<Description of Symbols for Major Parts of Drawings>

100: silicon growth furnace 110: quartz crucible

112: silicon melt 120: heating unit

130: side wall insulation member 140: heat shield member

180: dopant supply plate 182: dopant receiving groove

184: groove cover net 186: support groove

190: Low melting point dopant 200: Silicon seed crystal

300: impression device 400: silicon ingot

The present invention relates to an apparatus for producing a silicon single crystal ingot, and more particularly, to an apparatus for producing a silicon single crystal ingot having an improved structure so as to efficiently dope a low melting point dopant having a melting point lower than that of silicon.

In general, silicon wafers used in semiconductor manufacturing have a P-type or N-type dopant added in the growth process of pure silicon single crystals in order to have an appropriate resistivity value. At this time, since the melting point of boron (B) injected for the production of P-type silicon wafer is about 2180 ° C., which is higher than the melting point of silicon 1414 ° C., when polycrystalline silicon is loaded in a quartz crucible, Dopants are doped into the molten silicon by adding them together and melting them. The dopant having a melting point higher than that of silicon (1412 ° C.) is called a high melting point dopant.

On the other hand, dopants having a lower melting point than silicon's melting point (1412 ℃) is called a low melting point dopant, and such low melting dopants are antimony (Sb: 631 ℃), red (us phosphorus: 593 ℃), germanium (Ge: 937 ° C) and arsenic (As: 817 ° C). In order to add such a low melting dopant at a high concentration, when the doping method used for adding a high melting point dopant such as boron is used, all of the low melting dopants are melted / vaporized before the polycrystalline silicon is completely melted. It may be discharged / removed out of the growth furnace with an inert gas (e.g. Ar, etc.) flowing to remove the contaminating silicon oxide (which is the material that evaporates from the silicon melt). Therefore, it was difficult to produce a silicon single crystal having a desired specific resistance value.

On the other hand, when the low melting dopant is sealed without flowing an inert gas in the growth furnace to prevent it from being vaporized and discharged, silicon oxide (SiOx) contaminates the growth furnace and undesired carbon and metal impurities melt the silicon melt. There was a problem polluting. In addition, silicon oxide (SiOx) is deposited on the inner wall of the growth furnace, and silicon oxide (SiOx), which has been deposited on the inner wall of the growth furnace, falls on the surface of the silicon melt during the production of the silicon single crystal ingot, thereby impeding the growth of the silicon single crystal, thereby increasing the productivity of the silicon single crystal It was the cause of degradation.

Therefore, in the related art, polycrystalline silicon is completely dissolved for high concentration injection of low melting point dopant, and then pure doping is sprayed onto the surface of the molten silicon. In this case, however, the doped dopant is not completely melted into the silicon melt, and about 30% is vaporized and discharged / removed out of the furnace together with the inert gas. Thus, control over the dopant concentration is incomplete and waste of low melting dopant is generated. In addition, most of the low melting point dopants are toxic substances, which have a problem of causing environmental pollution when discharged to the outside of the growth furnace.

SUMMARY OF THE INVENTION The present invention has been made in an effort to improve the above-described problems of the related art, and to provide an apparatus for manufacturing a silicon single crystal ingot having an improved structure to efficiently dope a low melting point dopant.

An apparatus for producing a silicon single crystal ingot according to the present invention,

A quartz crucible in which a silicon melt is accommodated;

A heating unit for supplying a heat source to the silicon melt;

A side wall insulation member surrounding the heating portion to reduce heat loss to the side surface;

A heat shield member installed on the heating portion to reduce heat loss to an upper portion;

An impression device for introducing and pulling silicon seed crystals into the silicon melt;

Position adjuster for adjusting the height of the quartz crucible; And

It is spaced apart from the liquid-liquid interface of the silicon melt by a predetermined distance, the upper surface of the support groove is formed to be coupled to the heat shield member, the lower surface containing at least one dopant so that the low melting dopant can be charged A dopant supply plate having a groove formed therein and installed to support the low melting point dopant coupled to the dopant receiving groove and having a groove cover net formed of a mesh structure so that the silicon melt may flow into the dopant receiving groove; It includes.

Here, the diameter of the dopant supply plate is smaller than the inner diameter of the quartz crucible, the through hole is formed in the center so that the silicon ingot can pass.

Preferably, the dopant supply plate is formed of a quartz material, the dopant supply plate is installed 10mm to 100mm away from the solid-liquid interface of the silicon melt.

According to the present invention, when the silicon single crystal ingot is manufactured by the Czochralski crystal growth method, the low melting point dopant can be efficiently doped into the silicon melt, thereby minimizing the loss of the dopant. In particular, according to the present invention, since additional opening and closing of the single crystal growth furnace for injection of the dopant is not required, contamination in the single crystal growth furnace due to the opening and closing can be prevented, and as a result, a silicon ingot of good quality can be produced. have. In addition, according to the present invention, since the control of the doping amount is easy, it may be easy to manufacture a silicon single crystal having a desired specific resistance value.

Hereinafter, with reference to the accompanying drawings a preferred embodiment of the silicon single crystal ingot manufacturing apparatus according to the present invention will be described in detail.

In the production of silicon ingots, in general, the Czochralski crystal growth method and a silicon ingot production apparatus therefor are well known. The Czochralski crystal growth method is a method of crystal growth of the seed crystals into ingots of a predetermined diameter by dipping silicon seed crystals into a silicon melt and slowly pulling them up. Device for the invention.

1 is a schematic diagram of an apparatus for producing a silicon single crystal ingot according to the present invention. 2 and 3 are perspective views showing the lower surface and the upper surface of the dopant supply plate in FIG. 1, respectively.

Referring to Figure 1, the silicon single crystal ingot manufacturing apparatus according to the present invention is installed in the silicon growth furnace (100, furnace) and the silicon growth furnace (100) quartz crucible 110, heating unit 120, sidewall insulation The member 130, the heat shielding member 140, the pulling device 300, the position adjuster 500, and the dopant supply plate 180 are provided.

Specifically, the quartz crucible 110 is for accommodating silicon melt 112, and the silicon melt 112 may be obtained by loading and melting polycrystalline silicon in the quartz crucible 110. The heating part 120 is installed around the quartz crucible 110 to supply a heat source to the silicon melt 112 and is usually made of graphite material.

The sidewall insulation member 130 is installed to block heat emitted to the sidewall of the silicon growth path 100, and is installed to surround the heating part 120 to reduce heat loss to the side surface. do. Similarly, the heat shield 140 is installed on the heating part 120 to reduce heat loss to the upper portion.

The silicon seed crystal 200 may be introduced into the silicon melt 112 by the pulling device 300, and the height of the quartz crucible 110 may be adjusted by the positioning controller 500. have.

The dopant supply plate 180 is spaced a predetermined distance from the solid-liquid interface of the silicon melt 112 is installed on the upper portion. A support groove 186 is formed on the top surface of the dopant supply plate 180 to be fixedly coupled to the heat shield member 140. In addition, at least one dopant receiving groove 182 is formed on the bottom surface of the dopant supply plate 180 so that the low melting dopant 190 may be charged. Here, the low melting dopant 190 includes at least one selected from the group consisting of antimony (Sb), bismuth (Bi), red phosphorus, germanium (Ge), gallium (Ga), and arsenic (As). can do. In addition, the dopant receiving groove 182 is coupled to the groove cover net 184 so as to support the low melting point dopant 190 charged in this way. Preferably, a screw groove is further formed on an inner circumferential surface of the dopant receiving groove 182 to couple the groove cover net 184, and a screw thread is further formed in the groove cover net 184 to correspond to the screw groove. Can be. The groove cover net 184 is formed in a mesh structure so that the silicon melt 112 flows into the dopant receiving groove 182 through the groove cover net 184. In addition, the groove cover net 184 is installed to be completely drawn into the dopant receiving groove 182, it is preferable not to protrude to the outside. This is to prevent the low melting dopant 190 from being evaporated when it is exposed to an external high temperature.

The dopant supply plate 180 is manufactured to have a diameter smaller than the inner diameter of the quartz crucible 110, and a through hole 180a is formed at the center thereof so that the silicon ingot 400 can pass therethrough. Therefore, by adjusting the height position of the quartz crucible 110 by the position adjuster 500, the solid-liquid interface of the silicon melt 112 can be in contact with the lower surface of the dopant supply plate 180, more specifically The silicon melt 112 may be adjusted to be introduced into the dopant receiving groove 182. When the silicon melt 112 is introduced, the dopant 190 charged into the dopant receiving groove 182 may be easily dissolved in the silicon melt 112. In this process, there is little loss of dopant 190, and almost 100% of the dopant may be dissolved in the silicon melt 112. In addition, since the dopant supply plate 180 may be formed of a quartz material, the dopant supply plate 180 may not be concerned about contamination of the silicon melt 112 in contact with the dopant supply plate 180.

The dopant supply plate 180 is preferably installed 10mm to 100mm away from the solid-liquid interface of the silicon melt (112). In this case, when the dopant supply plate 180 is installed at a predetermined distance apart, the oxygen gas discharged from the silicon melt 112 is induced between the solid-liquid interface of the silicon melt 112 and the lower surface of the dopant supply plate 180. As a result, the oxygen partial pressure may be increased at the solid-liquid interface of the silicon melt 112. This increase in oxygen partial pressure can inhibit Marangoni flow, which is known to adversely affect the growth of silicon ingots. Here, the marangoni flow is one of the convection phenomena of the silicon melt 112. As the inner wall side of the quartz crucible 110 becomes higher on the surface of the silicon melt 112 than the growth side of the silicon ingot 400, By this temperature gradient, the flow phenomenon of the silicon melt 112 is generated from the inner wall side of the quartz crucible 110 to the growth side of the silicon ingot 400. Since the increase in the partial pressure of oxygen has already been reported to suppress the Marangoni flow, this side effect can be obtained by the installation of the dopant supply plate 180. When the separation distance of the dopant supply plate 180 is too far greater than 100 mm, it is difficult to expect an increase in the oxygen partial pressure at the solid-liquid interface of the silicon melt 112, and conversely, if it is too close to 10 mm or less, the dopant accommodation groove Since the low melting point dopant 190 charged inside 182 may be vaporized and leaked under the influence of an external high temperature, a distance of 10 mm to 100 mm is most preferable.

In the silicon ingot manufacturing apparatus having such a configuration, the silicon seed crystals 200 are dipped into the silicon melt 112, and the seed crystals 200 can be grown to ingots having a predetermined diameter by gradually pulling them up. If necessary, the bottom surface of the dopant supply plate 180 may be dipped into the silicon melt 112 so that the low melting dopant 190 charged into the dopant receiving groove 182 may be incorporated into the silicon melt 112. Through this process, dopant implantation and ingot growth can be performed in a one-step process, and additional opening and closing of the silicon growth furnace 100 for implantation of the dopant is not required. The contamination in the silicon growth path 100 can be prevented. As a result, a high quality silicon ingot 400 into which the low melting point dopant 190 is injected may be obtained.

According to the present invention, when the silicon single crystal ingot is manufactured by the Czochralski crystal growth method, the low melting point dopant can be efficiently doped into the silicon melt, thereby minimizing the loss of the dopant. In particular, according to the present invention, since additional opening and closing of the silicon growth furnace for injection of the dopant is not required, contamination in the silicon growth furnace due to the opening and closing can be prevented, and as a result, a silicon ingot of good quality can be produced. have. In addition, according to the present invention, since the control of the doping amount is easy, it may be easy to manufacture a silicon single crystal having a desired specific resistance value.

In the above, some exemplary embodiments have been described and illustrated in the accompanying drawings in order to facilitate understanding of the present invention, but these embodiments are merely exemplary and various modifications from the embodiments can be made by those skilled in the art. And it should be understood that other equivalent embodiments are possible. Therefore, the present invention is not limited to the illustrated and described structures and process sequences, but should be protected based on the technical spirit of the invention described in the claims.

Claims (4)

A quartz crucible in which a silicon melt is accommodated; A heating unit for supplying a heat source to the silicon melt; A side wall insulation member surrounding the heating portion to reduce heat loss to the side surface; A heat shield member installed on the heating portion to reduce heat loss to an upper portion; An impression device for introducing and pulling silicon seed crystals into the silicon melt; Position adjuster for adjusting the height of the quartz crucible; And It is spaced apart from the liquid-liquid interface of the silicon melt is installed on the upper portion, the upper surface is formed with a support groove to be coupled to the heat shield member, the lower surface at least one dopant receiving groove so that the low melting point dopant is charged A dopant supply plate which is formed to be coupled to the dopant receiving groove and is installed to support the low melting point dopant and has a groove cover net formed in a mesh structure so that the silicon melt may flow into the dopant receiving groove. An apparatus for producing a silicon single crystal ingot. The method of claim 1, The diameter of the dopant supply plate is smaller than the inner diameter of the quartz crucible, the center of the silicon single crystal ingot manufacturing apparatus, characterized in that the through hole is formed so that the silicon ingot can pass through. The method of claim 1, The dopant supply plate is a silicon single crystal ingot manufacturing apparatus, characterized in that formed of a quartz material. The method according to any one of claims 1 to 3, The dopant supply plate is a device for producing a silicon single crystal ingot, characterized in that installed 10mm to 100mm spaced apart from the solid-liquid interface of the silicon melt.

Images