JP2011054870A - Vapor deposition device and method of manufacturing silicon epitaxial wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor deposition device which extends an exchange cycle by preventing the local deterioration of a silica protection member and which makes the exchange of a thermocouple easy and a method of manufacturing a silicon epitaxial wafer using the same. <P>SOLUTION: A vapor deposition device 10 includes: a susceptor 14 on which a substrate for forming a thin film is laid in a chamber 11; a support member 13 for supporting the susceptor; a tubular shaft 16 to the upper end of which the support member is fixed; a thermocouple 19 which is inserted in the tubular shaft, is arranged in such a manner that the leading end of the thermocouple is protruded from the upper end of the tubular shaft and comes close to the lower surface of the susceptor, and measures the temperature of the susceptor; a silica protection member 18 with which the thermocouple is covered; and a protection cover 17 with which the upper end of the silica protection member is covered. A region from the upper end of the silica protection member to 2-10 mm under the upper end of the tubular shaft is covered with the protection cover. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vapor phase growth apparatus for forming a thin film on a substrate and a method for manufacturing a silicon epitaxial wafer using the same.

  In the manufacturing process of a semiconductor device, there is a process of supplying a reactive gas onto a semiconductor substrate in a chamber in which outside air is blocked and forming a thin film on the substrate. In such a process, a vapor phase growth apparatus is used that forms a thin film by causing a gas phase reaction on a substrate by supplying a raw material gas.

Among such apparatuses, a vapor phase growth apparatus that grows a single crystal of silicon on a silicon substrate is used in a manufacturing process of a semiconductor device such as an LSI. In this apparatus, normally, a silicon single crystal wafer in a chamber is heated to 1000 ° C. or more, and a mixed gas of a raw material gas such as silicon tetrachloride and trichlorosilane and hydrogen gas is supplied into the chamber for hydrogen reduction or thermal decomposition. Thus, a single crystal silicon thin film is grown on the silicon single crystal wafer by vapor phase growth. Then, after this vapor phase growth, cleaning is performed by flowing HCl gas into the chamber to remove silicon adhering to the chamber.
Such vapor phase growth is used in the semiconductor device manufacturing process to increase the breakdown voltage of the bipolar element. When manufacturing a megabit memory in the element as well, soft errors and latch-ups caused by alpha rays are prevented. This technology is necessary for

For such vapor phase growth, a vapor phase growth apparatus is used. A typical apparatus will be described with reference to a schematic diagram shown in FIG.
A vapor phase growth apparatus 101 shown in FIG. 6 processes a substrate in a state where it is shielded from outside air in a quartz chamber 110. In this chamber 110, a susceptor 108 made of silicon carbide and a silicon carbide ring 102 surrounding the susceptor 108 are arranged, and placed on the susceptor 108 by a heating lamp 104 arranged outside the chamber 110. In this structure, the substrate is heated.

The susceptor 108 is supported by a quartz support member 105, and the support member 105 is further supported by a quartz tubular shaft 106. The tubular shaft 106 is rotatable, and the support member 105 and the susceptor 108 are rotated by rotating the tubular shaft 106. A thermocouple 109 covered with a quartz protective member 107 is inserted into the tubular shaft 106, and the quartz protective member 107 covering the measurement portion at the tip of the thermocouple 109 is further covered with a protective cover 103 made of silicon carbide. Covered. The measurement portion at the tip of the thermocouple 109 covered with the quartz protective member 107 and the protective cover 103 is disposed directly below the susceptor 108 inside the support member 105.
Such a vapor phase growth apparatus is disclosed in Patent Document 1, for example.

JP-T-2001-522138

  However, even when the tip of the quartz protective member covering the thermocouple is covered with a silicon carbide protective cover, the quartz protective member is locally deteriorated by etching with HCl gas or the like during cleaning of the chamber. In addition, there is a problem that the protective cover is detached when the thermocouple is taken out.

  The present invention has been made in view of the above-mentioned problems, and it is possible to prolong the exchange cycle by preventing local deterioration of the quartz protective member, and to further facilitate the exchange of the thermocouple and the vapor growth apparatus thereof It aims at providing the manufacturing method of the silicon epitaxial wafer using this.

  In order to achieve the above object, the present invention provides at least a susceptor on which a substrate for forming a thin film is formed in a chamber, a support member that supports the susceptor, and a tubular shaft that is fixed to the upper end of the support member. A thermocouple that is inserted into the tubular shaft and has a tip projecting from the upper end of the tubular shaft so as to be close to the lower surface of the susceptor, and a quartz protection covering the thermocouple A vapor phase growth apparatus having a member and a protective cover covering an upper end portion of the quartz protective member, wherein at least the protective cover is downward from the upper end of the tubular shaft from the upper end of the quartz protective member. Provided is a vapor phase growth apparatus which covers an area of 2 to 10 mm.

Thus, if the protective cover covers an area of 2 to 10 mm downward from the upper end of the tubular shaft from the upper end of the quartz protective member, the quartz protective member is covered with the protective cover to the inside of the tubular shaft. Since the exposed portion of the quartz protective member can be prevented from coming into contact with HCl gas or the like and local deterioration can be suppressed, the replacement cycle is extended. Further, if the protective cover is the size of the present invention, the cost can be reduced by extending the replacement cycle of the quartz protective member, rather than increasing the cost. Furthermore, since the step at the boundary between the portion covered with the protective cover and the exposed portion of the quartz protective member is in the tubular shaft, the step is caught on the upper end of the tubular shaft and removed when the protective cover is removed. Nor.
As described above, with the vapor phase growth apparatus of the present invention, the quartz protective member replacement cycle can be extended, and further, the protective cover can be prevented from being removed when the thermocouple is replaced. It becomes a device that can.

At this time, the protective cover is preferably made of silicon carbide.
As described above, if the protective cover is made of silicon carbide, it is resistant to high temperatures, hardly deteriorated by HCl gas or the like, and further, the chamber and the substrate are less contaminated.

At this time, the susceptor may be a single wafer type.
Thus, a single wafer type susceptor can be used as the susceptor of the vapor phase growth apparatus of the present invention.

In addition, a silicon single crystal wafer is placed on the susceptor in the vapor phase growth apparatus of the present invention, and a silicon single crystal thin film is vapor grown on the main surface of the silicon single crystal wafer. A method for manufacturing a wafer is provided.
As described above, by using the vapor phase growth apparatus of the present invention to vapor-phase grow the silicon single crystal thin film on the main surface of the silicon single crystal wafer, a silicon epitaxial wafer can be manufactured at a low cost and with a high yield.

  As described above, with the vapor phase growth apparatus of the present invention, the replacement cycle of the quartz protective member for protecting the thermocouple can be extended, and the protective cover can be prevented from being removed when the thermocouple is taken out. Vapor phase growth can be performed with good yield.

It is the schematic which shows an example of the embodiment of the vapor phase growth apparatus of this invention. It is the elements on larger scale which show roughly an example of the embodiment of the vapor phase growth apparatus of the present invention. It is explanatory drawing for demonstrating the conventional vapor phase growth apparatus. It is explanatory drawing for demonstrating the conventional vapor phase growth apparatus. It is explanatory drawing for demonstrating the degradation part of the conventional quartz protective member. It is the schematic which shows an example of the conventional vapor phase growth apparatus. It is a graph which shows the relationship between the penetration length in the tubular shaft of a protective cover, and the lifetime of a quartz protective member. It is a graph which shows the relationship between the penetration length in the tubular shaft of a protective cover, and the ratio of the cost of the apparatus provided with the protective cover of the said penetration length, and the cost of the conventional apparatus.

Conventionally, in a vapor phase growth apparatus, a quartz protective member that protects a thermocouple may be locally deteriorated to shorten the replacement cycle, and further, the protective cover may be removed when the thermocouple is taken out. there were.
As a result of intensive studies on such problems, the present inventors have found the following.

3 and 4 are explanatory views for explaining a conventional vapor phase growth apparatus. FIG. 5 is an explanatory view for explaining a deteriorated portion of a conventional quartz protective member.
As shown in FIG. 5, when the local deterioration of the quartz protective member 107 is observed, the deterioration is not a crack or a crack, but the thickness of the quartz protective member 107 is thinned by scraping, and further, there is a hole. There was also a thing. Further, the deteriorated part of the quartz protective member 107 is in the same place every time, near the boundary between the protective cover 103 and the exposed part of the quartz protective member 107, and this part is the protective cover 103 of the quartz protective member 107. The portion that was exposed without being covered with, and was the portion closest to the atmosphere in the chamber. From this, it was found that the cause of local deterioration of the quartz protective member 107 was caused by HCl gas used to remove deposits in the chamber after the process.

As shown in FIG. 3, the shaft gas 111 such as hydrogen gas is ejected through the tubular shaft 106, and conventionally, the HCl gas 112 was considered difficult to enter the tubular shaft 106. For this reason, conventionally, it is considered that the deterioration cannot be prevented if the protective cover 103 is not excessively enlarged in consideration of cost and the like and the protective cover 103 covers the quartz protective member 107 to the vicinity of the upper end of the tubular shaft 106. It was.
However, as shown in FIG. 4, the present inventors have found that the HCl gas 112 has entered the tubular shaft 106 and the exposed portion of the quartz protective member 107 is locally deteriorated due to this. .

  Furthermore, the present inventors examined and investigated the relationship between the length of penetration of the protective cover into the tubular shaft (the length of penetration from the upper end of the tubular shaft downward) and the life of the quartz protective member. The results are shown in FIG. The intrusion length of the protective cover was 0 mm when the quartz protective member was covered up to the upper end position of the tubular shaft, and the lower part covered 16 levels of 0 to 15 mm with respect to the upper end position of the tubular shaft.

As shown in FIG. 7, the life of the quartz protective member was extremely short at 0 mm where there was no penetration, and the life was comparable to that of the conventional case by covering 1 mm below. The protective cover covers an area of 2 mm or more downward from the upper end of the tubular shaft, so that the life of the quartz protective member is 75 days, which is about 1.5 times longer than the conventional one. As the penetration length further increased, the life slightly increased, and at 12 mm or more, the life did not further increase. On the other hand, when the price of the protective cover exceeds 10 mm, it has risen drastically due to raw material costs and yield reduction.
In addition, the conventional cover removal rate at the time of taking out the thermocouple was 55.0%, but the protective cover covers the area of 2 mm or more from the upper end of the quartz protective member downward from the upper end of the tubular shaft. The rate was improved to 0%.

  From the above, the present inventors consider the cost reduction by extending the life of the quartz protective member and the cost increase by enlarging the protective cover, so that the protective cover is attached to the tubular shaft from the upper end of the quartz protective member. The present invention has been completed by finding that if it covers an area of 2 to 10 mm downward from the upper end, the life of the quartz protective member can be extended, the cover can be prevented from being removed, and the cost can be reduced as a whole.

Hereinafter, the vapor phase growth apparatus of the present invention will be described in detail as an example of an embodiment with reference to the drawings. However, the present invention is not limited to this.
FIG. 1 is a schematic view showing an example of an embodiment of the vapor phase growth apparatus of the present invention. FIG. 2 is a partially enlarged view schematically showing an example of an embodiment of the vapor phase growth apparatus of the present invention.

The vapor phase growth apparatus 10 of the present invention shown in FIG. 1 includes, for example, a silicon carbide susceptor 14 in which a counterbore on which a substrate for forming a thin film is placed is formed in a quartz chamber 11, and a susceptor 14. A silicon carbide ring 15 surrounding the periphery is arranged. The substrate is heated by a heating lamp 12 arranged outside the chamber 11.
The susceptor 14 is supported by a support member 13 made of quartz, and the support member 13 is fixed to the upper end of a tubular shaft 16 made of quartz. The tubular shaft 16 has a rotatable structure. When the tubular shaft 16 rotates, the support member 13 and the susceptor 14 rotate. A thermocouple 19 covered with a quartz protective member 18 is disposed in the tubular shaft 16, and the quartz protective member 18 covering the measurement portion at the tip of the thermocouple 19 is further covered with a protective cover 17. . The measuring portion at the tip of the thermocouple 19 covered with the quartz protective member 18 and the protective cover 17 protrudes from the upper end of the tubular shaft 16 and is disposed inside the support member 13 and immediately below the susceptor 14. .

As shown in FIG. 2, in the vapor phase growth apparatus 10 of the present invention, the protective cover 17 covers an area from 2 to 10 mm downward from the upper end of the tubular shaft 16 from the upper end of the quartz protective member 18. It is.
As shown in FIG. 2, the protective cover 17 covers an area of 2 mm or more downward from the upper end of the tubular shaft 16 from the upper end of the quartz protective member 18. Even when the quartz protective member 18 enters, the exposed portion of the quartz protective member 18 is located in a region where the concentration of the shaft gas 21 such as hydrogen gas is high, so that the quartz protective member 18 can be sufficiently prevented from being locally deteriorated. . Further, if the protective cover 17 protects an area of 10 mm or less from the upper end of the quartz protective member 18 downward from the upper end of the tubular shaft 16, the protective member made of quartz can be used rather than increasing the cost by increasing the protective cover 17. Since the cost reduction due to the extension of the 18 exchange cycles is greater, the cost when using the vapor phase growth apparatus of the present invention for vapor phase growth can be reduced as a whole.
Further, since the lower end of the protective cover 17 has entered the tubular shaft 16 by 2 mm or more, when the thermocouple 19 is taken out from the tubular shaft 16, the step at the lower end of the protective cover 17 comes into contact with the upper end of the tubular shaft 16. The protective cover 17 does not come off by being caught.

As such a material of the protective cover 17 of the vapor phase growth apparatus 10 of the present invention, for example, silicon carbide is preferable.
The protective cover 17 made of silicon carbide is resistant to high temperatures and HCl gas, and does not contaminate the chamber 11 or the substrate to be processed.

  Further, the susceptor 14 of the vapor phase growth apparatus 10 of the present invention is not particularly limited, and is a single wafer type in which substrates are placed one by one, or a batch in which a plurality of counterbore are formed and a plurality of substrates are placed. It can be of the formula

Using such a vapor phase growth apparatus 10 of the present invention, a silicon single crystal wafer is placed on the susceptor 14, and a silicon single crystal thin film is vapor-phase grown on the main surface of the silicon single crystal wafer to form a silicon epitaxial layer. It is preferable to manufacture a wafer.
After such vapor phase growth, silicon or the like adheres in the chamber 11, so the HCl gas 20 is flowed to remove the deposits, but the vapor phase growth apparatus 10 of the present invention uses the HCl gas 20 to protect quartz. The member 18 is hardly etched locally. Therefore, by using the vapor phase growth apparatus 10 of the present invention, a silicon epitaxial wafer can be manufactured with good yield and low cost.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these.
(Examples and comparative examples)
The cost of the apparatus according to the length of penetration of the protective cover of the vapor phase growth apparatus as shown in FIG. 1 or 6 into the tubular shaft was examined. The penetration length of the protective cover is 0 mm when the quartz protective member is covered up to the upper end position of the tubular shaft, and 0-15 mm downward from the upper end position of the tubular shaft (Example: 2-10 mm, Comparative Example: 0) (1 mm, 11-15 mm) covering 16 levels were examined. The protective cover was made of silicon carbide.

  Conventionally obtained by subtracting the cost increase (or cost reduction) by enlarging (or reducing) the protective cover from the cost reduction (or cost increase) due to the life extension (or shortening) of the quartz protective member. A graph showing the cost of 1 as 1 is shown in FIG.

  As shown in FIG. 8, in the comparative example, when the penetration length of the protective cover into the tubular shaft is in the range of 0 to 1 mm, the quartz protective member is locally deteriorated, the life is shortened, and the cost is increased. I have. In addition, in the range where the length of the protective cover entering the tubular shaft is in the range of 11 to 15 mm, the life of the quartz protective member was long, but the cost increase by increasing the protective cover becomes larger, and the cost as a whole is increased. It has become expensive. On the other hand, in the example, when the penetration length of the protective cover into the tubular shaft was in the range of 2 to 10 mm, the cost as a whole was lower than the conventional one.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

10 ... Vapor growth apparatus, 11 ... Chamber, 12 ... Heating lamp,
13 ... support member, 14 ... susceptor, 15 ... silicon carbide ring,
16 ... Tubular shaft, 17 ... Protective cover, 18 ... Quartz protective member,
19 ... Thermocouple, 20 ... HCl gas, 21 ... Shaft gas.

Claims (4)

At least a susceptor on which a substrate that forms a thin film in the chamber is placed; a support member that supports the susceptor; a tubular shaft that is fixed to the upper end of the support member; and a distal end that is inserted into the tubular shaft. A thermocouple that protrudes from the upper end of the tubular shaft and is disposed close to the lower surface of the susceptor, measures the temperature of the susceptor, a quartz protective member that covers the thermocouple, and an upper end portion of the quartz protective member A vapor phase growth apparatus having a protective cover for covering, at least,
The vapor phase growth apparatus characterized in that the protective cover covers an area of 2 to 10 mm downward from the upper end of the tubular shaft from the upper end of the quartz protective member.   The vapor phase growth apparatus according to claim 1, wherein the protective cover is made of silicon carbide.   The vapor phase growth apparatus according to claim 1 or 2, wherein the susceptor is a single wafer type. A silicon single crystal wafer is placed on the susceptor in the vapor phase growth apparatus according to any one of claims 1 to 3, and a silicon single crystal thin film is formed on a main surface of the silicon single crystal wafer. A method for producing a silicon epitaxial wafer, characterized by vapor phase growth.

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