JP4140601B2 - Gas rectifying member for single crystal pulling apparatus and manufacturing method thereof - Google Patents

Description

The present invention relates to a member for constituting a single crystal pulling apparatus, and more particularly to a gas rectifying member used for a single crystal pulling apparatus based on the Czochralski method as a semiconductor material.

A single crystal pulling apparatus pulls a silicon single crystal from a silicon melt in a crucible in the presence of an atmospheric gas by a method called a so-called Czochralski method. For example, Japanese Patent Publication No. 57-15079 discloses a single crystal pulling apparatus. It is known as a “single crystal manufacturing apparatus” as shown in FIG. As shown in FIG. 3, the apparatus disclosed in this publication is as follows: “A rotating shaft 2 is introduced into the furnace body 1 from below, and a crucible 4 is placed on the end surface of the rotating shaft 2 via a mounting table 3. Further, a heating element 5 and a heat insulating cylinder 6 are arranged around the crucible 4, and silicon is melted in the crucible 4 to obtain a melt 7. On the other hand, above the furnace body container 1, A rotating shaft 9 that slides is provided at the free end of the rotating shaft 9, and a silicon seed crystal 8 is attached to the rotating shaft 9 above the state in which the seed crystal 8 is in contact with the melt 7 in the crucible 4. To obtain a single crystal 10 of silicon continuing under the seed crystal 8.

When growing the single crystal, it is necessary to eliminate unnecessary reaction product gas so that it does not react on the liquid surface of the single crystal 10 and the melt 7. For this purpose, an inert gas such as argon is used as the atmospheric gas, and is supplied from above the furnace body container 1 to the single crystal and the liquid surface and discharged from the lower part of the furnace body container 1.
(2nd column of the above publication).

In this type of single crystal pulling apparatus, it is necessary to form a clean atmosphere so that impurities are not mixed into the Si melt in the crucible in order to maintain the purity of the resulting semiconductor material. For this reason, a gas rectifying member for rectifying the inert gas flowing from above is installed on the crucible for melting Si. This gas rectification prevents impurities such as SiO gas generated in the furnace at high temperature from flowing into the crucible and mixing into the Si melt. Moreover, in order to increase the temperature gradient of the Si single crystal in the pulling direction that affects the pulling speed of the Si single crystal, it also plays a role of blocking radiant heat from the Peter and the Si melt.

As described above, in order to increase the temperature gradient of the Si single crystal, the radiant heat from the melt and the crucible must be sufficiently blocked. Moreover, even if a graphite material is excellent in heat resistance, it cannot fully exhibit heat insulation. Therefore, a gas rectifying member for a single crystal pulling apparatus is provided in which graphite is used as a base material and a heat insulating material is combined in order to block heat radiation. For example, Japanese Patent Application Laid-Open No. 9-183686 is composed of a cylinder and a collar that coaxially surrounds a pulling single crystal rod, and the collar is formed of a high-purity graphite material, and a heat insulating material overlapped on multiple layers covers the upper surface of the collar. Further, the upper surface is coated with a high purity graphite material, or the surface of the high purity graphite material to be coated is coated with silicon carbide or the like.

However, the gas rectifying member is not only expensive due to the processing accuracy, but also has a problem that the heat capacity is increased, and further, the SiO gas enters from the interposer and the following chemical reaction occurs, and the heat insulating material is silicified. However, it sometimes causes generation of particles.

SiO + 2C → SiC + CO

Therefore, the object of the present invention is to provide a desired temperature gradient necessary for pulling a single crystal and to have high durability and cost without causing contamination in the single crystal pulling apparatus or contamination of the single crystal. It is to provide a gas rectifying member that can be reduced.

In order to solve the above problems, the means taken by the invention of claim 1 will be described with reference numerals used in the description of the embodiments.
“A gas rectifying member installed on a crucible for melting a semiconductor raw material and rectifying an inert gas flowing into the sealed body from above, with a carbonaceous fiber molded body as a base material. A thermosetting resin carbide formed by carbonizing after thermosetting the thermosetting resin is formed as an intermediate layer, and further, a film made of pyrolytic carbon is formed on the surface of the intermediate layer,
A gas rectifying member for a single crystal pulling apparatus, wherein a film of pyrolytic carbon is prevented from being formed on each of the fibers of the carbonaceous fiber molded body. "
That's it.

Furthermore, the means taken by the invention of claim 2 is that “the gas rectifying member 60 is installed on the crucible 10 for melting the semiconductor raw material and rectifies the inert gas flowing into the sealed body 50 from above. A manufacturing method comprising:
A carbonaceous fiber molded body 61 is used as a base material, and at least one group of a phenol resin, a furan resin, a divinylbenzene resin, or a condensed polycyclic aromatic compound and a hydroxymethyl group or a halomethyl group is formed on the surface of the base material. One or two or more types of thermosetting resins selected from compositions comprising a combination of an aromatic cross-linking agent composed of two or more aromatic rings composed of one or two or more aromatic rings and an acid catalyst. Apply to the molded body 61,
After heat curing, apply and cure again,
Forming a carbonized thermosetting resin carbide as the intermediate layer 62;
Further, a film 63 made of pyrolytic carbon is formed on the surface of the intermediate layer 62,
A method for producing a gas rectifying member for a single crystal pulling apparatus, wherein a film of pyrolytic carbon is prevented from being formed on each of the fibers of the carbonaceous fiber molded body 61 . ".

As shown in FIG. 1, the gas rectifying member 60 according to the present invention is installed above the crucible 10 for melting the semiconductor raw material, and the entire base material can be formed by the carbonaceous fiber molded body 61. is necessary. The reason is that such a carbonaceous fiber molded body 61 has low heat conductivity and high heat insulation properties. Therefore, if it is formed above the crucible 10, the melt or radiant heat applied from the crucible 10 to the single crystal can be obtained. This is because the desired temperature gradient necessary for pulling up the single crystal can be obtained.

Next, an intermediate layer 62 made of a thermosetting resin carbide needs to be formed on the surface of the carbonaceous fiber molded body 61. The thermosetting resin carbide forming the intermediate layer 62 contains at least one group selected from a phenol resin, a furan resin, a divinylbenzene resin, a condensed polycyclic aromatic compound, a hydroxymethyl group, and a halomethyl group. One or two or more thermosetting resins selected from a composition comprising an aromatic crosslinker consisting of one or more aromatic rings composed of one or more aromatic rings and an acid catalyst are heat-cured and then carbonized. Formed. The reason why the intermediate layer 62 made of a thermosetting resin carbide is formed on the surface of the carbonaceous fiber molded body 61 is that if the intermediate layer 62 is not present, the pyrolytic carbon coating 63 is difficult to be formed, and heat is applied to each fiber. Since cracked carbon is coated, the pyrolytic carbon film 63 is further formed on the cracked carbon, thereby increasing the weight, resulting in an increase in heat capacity and deterioration of heat insulation characteristics.

Further, it is necessary to form a film 63 made of pyrolytic carbon on the surface of the thermosetting resin carbide formed as the intermediate layer 62. The reason is that since the surface layer of the pyrolytic carbon coating 63 is dense, the oxidation resistance and gas impermeability are also greatly improved, and the SiO gas or Si gas and the thermosetting resin carbide come into contact with each other. This is to prevent reaction with carbon of the curable resin carbide. On the other hand, since the thermal conductivity of the surface layer of the coating 63 made of pyrolytic carbon is very low in the direction perpendicular to the pyrolytic carbon deposition surface, the original thermal conductivity of the carbonaceous fiber molded body 61 is increased. This is because high thermal insulation is sufficiently secured. In addition, since there is a risk of carbon dropping from the thermosetting resin carbide, if these disadvantages are prevented by the coating 63 made of dense pyrolytic carbon, contamination in the single crystal pulling apparatus 100 and contamination of the single crystal are prevented. Because it can. Furthermore, since the surface layer of the coating 63 made of pyrolytic carbon has a high density, not only the intermediate layer 62 made of a thermosetting resin carbide but also the mechanical strength of the carbonaceous fiber molded body 61 is improved. This is because the oxidation resistance and gas impermeability are also greatly improved.

The gas rectifying member 60 for the single crystal pulling apparatus 100 according to the present invention is “a gas rectifying member that is installed on the crucible 10 for melting the semiconductor raw material and rectifies the inert gas flowing from above into the sealed body 50. 60, the carbonaceous fiber molded body 61 is used as a base material, and a thermosetting resin carbide formed by carbonizing the thermosetting resin after heat-curing the thermosetting resin on the surface of the base material is formed as the intermediate layer 62. the intermediate coatings 63 made of pyrolytic carbon on the surface of the layer 62 formed by Ri Na, and characterized in that is prevented film formation of pyrolytic carbon "to one one fiber charcoal predisposition fiber molded body By doing so, since the carbonaceous fiber molded body 61 is provided with high heat insulation, a desired temperature gradient can be obtained and a high-quality single crystal can be obtained. Further, since the coating 63 made of dense pyrolytic carbon is firmly formed on the intermediate layer 62, it does not cause contamination in the sealed body 50 or single crystal, but also prevents silicidation of the gas rectifying member 60. Therefore, it is possible to obtain a gas rectifying member for a single crystal pulling apparatus having high durability and low cost.

Next, the present invention will be described with reference to the embodiment shown in the drawings. FIG. 1 is a longitudinal sectional view of a single crystal pulling apparatus 100 to which a gas rectifying member 60 according to the present invention is applied. This single crystal pulling apparatus 100 is a device in which a crucible 10 for melting a semiconductor raw material is accommodated in a hermetically sealed main body 50 so as to be rotatable on a rotating shaft, and the crucible 10 is heated around the crucible 10. The heater 20 is arranged. A gas rectifying member 60 according to the present invention is disposed above the crucible 10.

The crucible 10 has a double structure having a quartz crucible 11 as a portion in direct contact with the molten semiconductor material, and the heater 20 is generally a so-called graphite heater. It becomes substantially constant in the positional relationship as shown in FIG.

As shown in FIG. 2, the gas rectifying member 60 is formed using the carbonaceous fiber molded body 61 as a base material. Further, a thermosetting resin carbide is formed as an intermediate layer 62 on the surface of the carbonaceous fiber molded body 61, Further, a coating 63 made of pyrolytic carbon is formed on the surface of the intermediate layer 62. The carbonaceous fiber molded body 61, the thermosetting resin carbide forming the intermediate layer 62 and the coating 63 made of pyrolytic carbon are manufactured or formed as shown in detail in the following examples.

An inverted conical carbonaceous fiber molded body 61 having a major outer diameter of 340 mm, a minor outer diameter of 200 mm, a thickness of 5 mm, and a height of 350 mm was formed. The obtained carbonaceous fiber molded body 61 has a 1: 2 molar ratio of a benzene-soluble component (average molecular weight 340) of petroleum-based pitch having a softening point of 80 ° C. and P-xylene glycol as a thermosetting resin. And 1 wt% P-toluenesulfonic acid was added thereto, and this was reacted at 130 ° C. for 40 minutes.

This reaction product was melted at 130 ° C., applied to the carbonaceous fiber molded body 61, cured at 180 ° C., then applied again, cured, and baked at 1900 ° C.

A carbonaceous fiber molded body 61 having an intermediate layer 62 made of a thermosetting resin carbide formed on the surface is placed in a CVD furnace, and methane gas is heated in a furnace using hydrogen gas as a carrier under conditions of a deposition temperature of 2000 ° C. and a pressure of 30 Torr. Was continuously fed into. Thereby, the film 63 made of pyrolytic carbon having a thickness of 50 μm was formed on the entire surface of the thermosetting resin carbide.

It is a schematic longitudinal cross-sectional view of the single crystal pulling apparatus which employ | adopted the gas rectification | straightening member which concerns on this invention. It is a partial expanded sectional view of the gas rectification member. It is sectional drawing which shows the conventional silicon single crystal pulling apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Single crystal pulling apparatus 10 Crucible 11 Quartz crucible 20 Heater 50 Sealing main body 60 Gas rectifying member 61 Carbonaceous fiber molded body 62 Intermediate layer 63 made of thermosetting resin carbide 63 Film made of pyrolytic carbon

Claims (2)

A gas rectifying member installed on a crucible for melting a semiconductor raw material and rectifying an inert gas flowing into the sealed body from above, with a carbonaceous fiber molded body as a base material, and heat on the surface of the base material A thermosetting resin carbide formed by heating and curing the curable resin is formed as an intermediate layer, and further, a film made of pyrolytic carbon is formed on the surface of the intermediate layer,
A gas rectifying member for a single crystal pulling apparatus, wherein a film of pyrolytic carbon is prevented from being formed on each of the fibers of the carbonaceous fiber molded body. A method for producing a gas rectifying member for rectifying an inert gas which is installed on a crucible for melting a semiconductor raw material and flows into the sealed body from above,
A carbonaceous fiber molded body is used as a base material, and at least one group selected from a phenol resin, a furan resin, a divinylbenzene resin, or a condensed polycyclic aromatic compound and a hydroxymethyl group or a halomethyl group is formed on the surface of the base material. One or more thermosetting resins selected from a composition comprising a combination of an aromatic cross-linking agent comprising one or more aromatic rings composed of one or more aromatic rings and an acid catalyst are formed into the carbon fiber molding. Smear on the body,
After heat curing, apply and cure again,
Forming a carbonized thermosetting resin carbide as an intermediate layer,
Furthermore, a film made of pyrolytic carbon is formed on the surface of this intermediate layer,
Method for producing a gas rectifying member for a single crystal pulling apparatus which is characterized that you made is prevented film formation of pyrolytic carbon to one one fiber of carbonaceous fiber molding.

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