TW201816202A - Heat shield of crystal seed growth crucible and method thereof - Google Patents

Abstract

This invention provides a heat shield of a crystal seed growth crucible and a method thereof. The heat shield comprises a shield body, and the shield body has a receiving space. The material of the shield body is used as quartz glass to prevent it from Molybdenum and Carbon pollution sources and it can efficiently prevent the crystal seed from the pollution of the heat shield.

Description

   Hot screen of single crystal growth furnace and manufacturing method thereof   

The invention relates to a single crystal growth furnace heat shield, which belongs to the production equipment of single crystal silicon.

Monocrystalline silicon is a crystal with a complete lattice structure and is a good semiconductor material. It is currently widely used in the manufacture of semiconductor elements and solar cells. The modern downstream IC industry has higher and higher requirements for the quality of silicon wafer materials, which requires that silicon single crystals grown by the pulling method have fewer defects and impurities.

The existing single crystal silicon manufacturing equipment is a single crystal growth furnace, and the furnace body mainly includes seven parts: a furnace bottom, a lower furnace body, a middle furnace body, an upper furnace cover, an isolation valve, an auxiliary furnace chamber and a lifting device. A heat shield is hung on the upper furnace lid. The use of the heat shield of the single crystal growth furnace reduces the radiant heat loss of the silicon melt and crucible in the vertical direction, which greatly reduces the power required to grow the crystal; it changes the flow mode and speed of argon and takes it away more effectively. Silicon monoxide.

However, the heat shield material of the current silicon single crystal growth furnace is generally molybdenum or silicon carbide or coated high-purity graphite. Since the heat shield is located very close to the silicon melt, it is easy to introduce molybdenum, carbon and other pollution sources. So choosing the right heat shield material is an important content of a straight-pull silicon thermal field design.

The purpose of the present invention is to provide a single crystal growth furnace heat shield and a manufacturing method thereof, in order to solve the existing single crystal growth furnace heat shield because the material used is molybdenum or silicon carbide or coated high-purity graphite, which is easy to apply to single crystals. Problems causing pollution.

In order to solve the above technical problems, the present invention provides a single crystal growth furnace hot screen, which includes a screen body, and an accommodation space is formed in the screen body, and the screen body is made of quartz glass.

Optionally, in the hot screen of the single crystal growth furnace, the outer surface and the inner surface of the screen body are coated with a barium hydroxide coating.

Optionally, in the hot screen of the single crystal growth furnace, the barium hydroxide coating layer uses barium hydroxide containing crystal water.

Optionally, in the heat shield of the single crystal growth furnace, the shield body is filled with a heat insulation material to form a heat insulation layer.

Optionally, in the heat shield of the single crystal growth furnace, the material of the heat insulation layer is a solid carbon felt.

The invention also provides a method for manufacturing a heat shield of a single crystal growth furnace, which comprises: forming a shield body using a quartz material.

Optionally, in the method for manufacturing a heat shield of a single crystal growth furnace, the outer surface and the inner surface of the shield body are coated with a barium hydroxide coating.

Optionally, in the method for manufacturing a heat shield of a single crystal growth furnace, the barium hydroxide coating layer uses barium hydroxide containing crystal water.

Optionally, in the method for manufacturing a heat shield of a single crystal growth furnace, the shield body is filled with a heat insulation material to form a heat insulation layer.

Optionally, in the method for manufacturing a heat shield of a single crystal growth furnace, a material of the heat insulation layer is a solid carbon felt.

The heat shield of a single crystal growth furnace provided by the present invention and a method for manufacturing the same include a shield body, in which a accommodating space is formed. The material of the shield body is quartz glass, which can avoid the introduction of pollution sources such as molybdenum and carbon, which can effectively Reduce the crystal contamination of the heat shield of the single crystal growth furnace. Further, the outer surface and the inner surface of the screen body are coated with a barium hydroxide coating containing crystal water, and the barium hydroxide coating reacts with carbon dioxide in the air to form barium carbonate. When heated in a single crystal growth furnace, the barium carbonate decomposes to form barium oxide, and then reacts with silicon dioxide in quartz glass to form a barium silicate material with a high melting point. Due to the catalysis of barium silicate, a layer of dense and fine white silica crystals is formed on the surface of the screen body. The white silica crystals increase the strength of the screen body and reduce the phenomenon of high temperature softening.

10‧‧‧Screen

11‧‧‧ Insulation

FIG. 1 is a schematic diagram of a heat shield structure of a single crystal growth furnace provided by the present invention; FIG. 2 is a schematic flowchart of a method of manufacturing a heat shield of a single crystal growth furnace provided by the present invention.

The single-crystal growth furnace hot screen and the manufacturing method thereof provided by the present invention will be further described in detail below with reference to the drawings and specific embodiments. The advantages and features of the invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and all use inaccurate proportions, which are only used to facilitate and clearly assist the description of the embodiments of the present invention.

The present invention provides a single crystal growth furnace thermal screen. As shown in FIG. 1, the screen includes a screen body 10. An accommodation space is formed in the screen body 10, and the screen body 10 is made of quartz glass. Using quartz glass as the screen body of the heat shield of the single crystal growth furnace, avoiding the introduction of molybdenum, carbon and other pollution sources, can effectively reduce the crystal pollution of the heat shield of the single crystal growth furnace. Further, and because the reflectivity of quartz glass is high, the heat radiated from the melt surface to the heat shield is low. In addition, quartz glass has a lower thermal conductivity than graphite, so the thermal insulation performance is better.

Specifically, the outer surface and the inner surface of the screen body 10 are coated with a barium hydroxide coating (not shown in the figure); and the barium hydroxide coating is barium hydroxide containing crystal water. The barium hydroxide containing crystal water will react with carbon dioxide in the air to form barium carbonate. When heated in a single crystal growth furnace, the barium carbonate decomposes to form barium oxide, and then reacts with quartz glass, which is the material of the screen body 10, to form a barium silicate material with a high melting point. Due to the catalytic action of the barium silicate material, a layer of dense and fine white silica crystals is formed on the surface of the screen body 10, and the white silica crystals can increase the strength of the screen body 10 and reduce the phenomenon of high temperature softening. .

Specifically, the screen body 10 is filled with a heat insulation material, and a heat insulation layer 11 is formed. The material of the thermal insulation layer 11 is preferably a solid carbon felt. Because the solid carbon felt has better thermal insulation performance and the thermal conductivity of the screen body 10 is low, this will reduce the heat from the melt to the crystal and help the crystal to cool down.

The present invention provides a method for manufacturing a heat shield of a single crystal growth furnace, and a schematic flow chart is shown in FIG. 2. The method for manufacturing a heat shield of a single crystal growth furnace includes the following steps: Step S21, providing a screen body with an accommodation space; In step S22, a heat insulating material is filled into the screen body to form a heat insulating layer.

Specifically, the material of the screen body is quartz glass, and the use of quartz glass as the screen body of the heat shield of the single crystal growth furnace can avoid the introduction of molybdenum, carbon and other pollution sources, which can effectively reduce the heat shield of the single crystal growth furnace. Crystal contamination. Further, because the reflectivity of the quartz glass is high, the heat radiated from the melt surface to the heat shield is low. In addition, quartz glass has a lower thermal conductivity than graphite, so the thermal insulation performance is better.

Specifically, the outer surface and the inner surface of the screen body are coated with a barium hydroxide coating containing crystal water, and the barium hydroxide containing crystal water will react with carbon dioxide in the air to form barium carbonate. When heated in a single crystal growth furnace, the barium carbonate decomposes to form barium oxide, and then reacts with quartz glass, which is the material of the screen body, to form a barium silicate material with a high melting point. Due to the catalysis of the barium silicate material, a layer of dense and fine white silica crystal is formed on the surface of the screen body. The white silica crystal can increase the strength of the screen body and reduce the phenomenon of high temperature softening.

Specifically, the material of the heat-insulating layer is a solid carbon felt because the solid carbon felt has excellent thermal insulation properties. And the thermal conductivity of the screen body 10 is low, which will reduce the heat from the melt to the crystal and help the crystal to cool down.

The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those skilled in the art in accordance with the above disclosure are within the protection scope of the patent application.

Claims (10)

    A heat shield for a single crystal growth furnace includes a shield body, and an accommodation space is formed in the shield body. The material of the shield body is quartz glass.         The single crystal growth furnace hot screen according to claim 1, wherein the outer surface and the inner surface of the screen body are coated with a barium hydroxide coating.         The single crystal growth furnace heat shield according to claim 2, wherein the barium hydroxide coating is barium hydroxide containing crystal water.         The single crystal growth furnace hot screen according to claim 2, wherein the screen body is filled with a heat insulation material to form a heat insulation layer.         The single crystal growth furnace heat shield according to claim 4, wherein the material of the heat insulation layer is a solid carbon felt.         A method for manufacturing a heat shield of a single crystal growth furnace includes forming a shield body using a quartz material.         The method for manufacturing a heat shield of a single crystal growth furnace according to claim 6, wherein the outer surface and the inner surface of the screen body are coated with a barium hydroxide coating.         The method for manufacturing a heat shield of a single crystal growth furnace according to claim 7, wherein the barium hydroxide coating is barium hydroxide containing crystal water.         The method for manufacturing a heat shield of a single crystal growth furnace according to claim 6, wherein the shield body is filled with a heat insulation material to form a heat insulation layer.         The method for manufacturing a heat shield of a single crystal growth furnace according to claim 9, wherein a material of the heat insulation layer is a solid carbon felt.