JP5267366B2 - Silicon wafer processing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing apparatus of a silicon wafer in which contamination from a member containing metal is prevented, and the removal of a by-product when in maintenance is easy. <P>SOLUTION: A chamber 20 and a plurality of members comprising a material containing metal attached to the chamber 20 are equipped. Among the plurality of members, DLC coating is applied to an exhaust piping 41 and an exhaust cap 42 to which the adhesion of the by-product is relatively many, and quartz coating is applied to other members to which the adhesion of the by-product is relatively few. Since, the coating material is selected according to the easiness of the adhesion of the by-product, it becomes possible to remove the by-product easily when in maintenance, while preventing metal contamination. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a silicon wafer processing apparatus, and more particularly to a silicon wafer processing apparatus in which a metal-containing member is coated with a coating for preventing contamination.

  One of silicon wafer processing apparatuses is an epitaxial growth apparatus. The epitaxial growth apparatus is an apparatus mainly used in the manufacturing process of a silicon wafer, and is an apparatus for growing a silicon epitaxial layer on the surface of a mirror-polished silicon wafer. In addition, the epitaxial growth apparatus may be used for selective epitaxial growth in a device pre-process.

  In the epitaxial growth apparatus, main members such as a chamber are made of quartz in order to prevent contamination of the silicon wafer. However, since it is difficult to form all the members with quartz, there are some members such as a base plate for ensuring the mechanical strength of the chamber and an exhaust mechanism for guiding the gas exhausted from the chamber. Metal materials are used. As a method for preventing the contamination of the silicon wafer by such a metal member, Patent Document 1 describes a method of coating a portion of the metal member exposed to the process gas with quartz.

JP 2009-49047 A

  However, when epitaxial growth is performed, a large amount of by-products adhere mainly to the exhaust mechanism. The adhering by-product not only obstructs the gas flow, but also becomes a particle and may contaminate the silicon wafer. Therefore, it is necessary to remove this by regular maintenance.

  At the time of maintenance, the exhaust mechanism is removed from the chamber or the like and opened to the atmosphere. As a result, the attached by-products take in oxygen and moisture in the atmosphere to form polysiloxane and the like. In order to remove this, it is necessary to use a solution containing hydrofluoric acid. However, since hydrofluoric acid attacks quartz, if a quartz coating is applied to a member to which many by-products are attached, the solution containing hydrofluoric acid is removed. It cannot be used, and maintenance becomes very difficult.

  Such a problem is applicable not only to the epitaxial growth apparatus but also to all silicon wafer processing apparatuses in which by-products can adhere to various members. Moreover, although the by-product attachment location differs depending on the type of apparatus, there are places where by-products are particularly likely to adhere in any apparatus.

  Accordingly, an object of the present invention is to provide a silicon wafer processing apparatus in which contamination from a metal-containing member is prevented and by-products can be easily removed during maintenance.

  A silicon wafer processing apparatus according to the present invention includes a chamber in which a silicon wafer is accommodated and a predetermined processing is performed by an introduced gas, and a plurality of members attached to the chamber and made of a material containing metal. In the wafer processing apparatus, a first coating made of a material that is not affected by at least hydrofluoric acid is applied to a member having a relatively large amount of by-product adhesion due to the gas among the plurality of members. The second coating made of quartz is applied to a member with relatively little by-product adhesion due to.

  According to the present invention, since the coating material is selected according to the ease of adhesion of by-products, it is possible to easily remove by-products during maintenance while preventing metal contamination. Become.

  In the present invention, the first coating is preferably made of DLC (diamond-like carbon). Since DLC is not affected by hydrofluoric acid, it is possible to remove by-products including siloxane and the like using an aqueous hydrofluoric acid solution during maintenance.

  In the present invention, among the plurality of members, the temperature given to the member coated with the first coating may be lower than the temperature given to at least one of the members coated with the second coating. preferable. This is because the second coating made of quartz is excellent in heat resistance, whereas the first coating made of a non-quartz material such as DLC is difficult to have the same heat resistance as quartz.

  In the present invention, it is preferable that the plurality of members include an exhaust mechanism for guiding a gas exhausted from the chamber, and at least a part of the exhaust mechanism is provided with the first coating. This facilitates maintenance of an apparatus such as an epitaxial growth apparatus in which by-products easily adhere to the exhaust mechanism.

  In the present invention, it is preferable that the plurality of members further include an introduction mechanism for introducing a gas into the chamber, and at least a part of the introduction mechanism is provided with the second coating. In an epitaxial growth apparatus or the like, since a by-product hardly adheres to the introduction mechanism, a second coating made of quartz can be used in such a place.

  In the present invention, it is preferable that the plurality of members further include a base plate for holding the chamber, and the second coating is applied to the base plate. This is because the base plate is a member that is exposed to a relatively high temperature, and adhesion of by-products hardly occurs. Therefore, it is preferable to apply a second coating having excellent heat resistance to such a member.

  In the present invention, the exhaust mechanism includes an exhaust pipe and an exhaust cap that connects the base plate and the exhaust pipe, and the introduction mechanism connects the introduction pipe, the base plate, and the introduction pipe. The exhaust pipe and the exhaust cap are both coated with the first coating, and the introduction pipe and the injection cap are both the second. It is preferable that the coating is applied. This is because both the exhaust pipe and the exhaust cap are portions where by-products are likely to adhere.

  In the present invention, the plurality of members further include a slit valve for loading the silicon wafer into the chamber or unloading the silicon wafer from the chamber, and the slit valve includes the second valve. A coating is preferably applied. According to this, metal contamination from the slit valve is also prevented.

  In the present invention, the plurality of members further include an insertion portion of a rotation shaft for rotating the silicon wafer in the chamber, and the second coating is applied to the insertion portion of the rotation shaft. It is preferable. According to this, metal contamination from the rotation shaft insertion portion is also prevented.

  Thus, according to the present invention, since the coating material is selected according to the ease of attachment of the by-product, the by-product is easily removed during maintenance while preventing metal contamination. It becomes possible.

1 is a schematic cross-sectional view showing the structure of a silicon wafer processing apparatus 10 according to a preferred embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic cross-sectional view showing the structure of a silicon wafer processing apparatus 10 according to a preferred embodiment of the present invention. The silicon wafer processing apparatus 10 according to the present embodiment is an epitaxial growth apparatus, and hence is hereinafter referred to as an epitaxial growth apparatus 10.

  As shown in FIG. 1, the epitaxial growth apparatus 10 according to the present embodiment includes a chamber 20, an introduction mechanism 30 that introduces gas into the chamber 20, and an exhaust mechanism 40 that guides gas exhausted from the chamber 20. ing.

  The chamber 20 is composed of four members including a disk-shaped upper member 21, a funnel-shaped lower member 22, and ring-shaped side members 23 and 24, and these are combined as shown in FIG. 20 is configured. These members 21 to 24 are all made of quartz.

  Inside the chamber 20 are provided a susceptor 25 that holds the silicon wafer 100 to be processed, and an elevating mechanism 26 that places the silicon wafer 100 on the susceptor 25 or takes the silicon wafer 100 out of the susceptor 25. The susceptor 25 is made of carbon coated with SiC, but the elevating mechanism 26 is made of quartz.

  The lower member 22 constituting the chamber 20 is provided with a slit valve 27 for loading the silicon wafer 100 into the chamber 20 or unloading the silicon wafer 100 from the chamber 20. The slit valve 27 is made of a metal material, and the surface thereof is coated with quartz. Thereby, contamination of the silicon wafer 100 by the metal constituting the slit valve 27 is prevented. The slit valve 27 is a member that is exposed to a high temperature during epitaxial growth. However, the quartz coating has high heat resistance, so that the coating is not deteriorated by heat. Further, since the slit valve 27 is a member with little by-product adhesion, there is little need for cleaning with hydrofluoric acid.

  Further, a rotation shaft 28 for rotating the silicon wafer 100 is provided inside the chamber 20. Although the rotation shaft 28 itself is made of quartz, the connection portion with the motor 50 for rotating the rotation shaft 28 and the connection portion with the actuator 60 for moving the rotation shaft 28 up and down (rotation shaft insertion portion). Are partially used. More specifically, the rotation shaft insertion portion includes a rotation housing 28a, a wafer lift housing 28b, a collet 28c, an isolation housing 28d, and the like, and these are made of metal. Such a rotation shaft insertion portion is coated with quartz, thereby preventing the silicon wafer 100 from being contaminated by the metal constituting the rotation shaft insertion portion. The rotation shaft insertion portion is a member having a complicated shape, but quartz can be easily coated even with a complicated shape by using polysilazane. Further, since the rotation shaft insertion portion is a member with little by-product adhesion, there is little need for cleaning with hydrofluoric acid.

  As shown in FIG. 1, a ring-shaped base plate 29 that holds the chamber 20 is provided around the chamber 20. The base plate 29 is made of a metal material, and serves to secure the mechanical strength of the chamber 20 while fixing the members 21 to 24 constituting the chamber 20. The base plate 29 also serves as a connection between the chamber 20 and the introduction mechanism 30 and the exhaust mechanism 40. For this reason, a part of the base plate 29 comes into contact with the gas introduced into the chamber 20 and the gas exhausted from the chamber 20.

  In the present embodiment, the base plate 29 is coated with quartz, thereby preventing the silicon wafer from being contaminated by the metal constituting the base plate 29. The base plate 29 is a member that is exposed to a high temperature during epitaxial growth. However, the quartz coating has high heat resistance, so that the coating does not deteriorate due to heat. Further, since the base plate 29 is a member with little by-product adhesion, there is little need for cleaning with hydrofluoric acid.

  As shown in FIG. 1, the introduction mechanism 30 includes two introduction pipes 31, an injection cap 32 that connects the base plate 29 and the introduction pipe 31, and a collective introduction pipe 34. The introduction pipe 31 is a pipe connected to the collective introduction pipe 34 via the flow rate adjustment valve 33. The collective introduction pipe 34 is connected via a main valve 35 to a main introduction pipe 36 connected to a cylinder (not shown) of process gas and carrier gas. The process gas or carrier gas flowing through the introduction pipe 31 is introduced into the chamber 20 through the injection cap 32. During maintenance, the main valve 35 is closed. Therefore, the introduction mechanism 30 is defined as a pipe in a portion downstream of the main valve 35 that defines the boundary with the main introduction pipe 36.

During the epitaxial growth, for example, SiHCl ₃ (trichlorosilane) and H ₂ (hydrogen gas) are introduced through the introduction mechanism 30, and Si (silicon) generated by the decomposition of trichlorosilane is deposited on the surface of the silicon wafer 100. The HCl (hydrogen chloride) generated by the decomposition of trichlorosilane is discharged through the exhaust mechanism 40. Of the introduced trichlorosilane, the portion used for epitaxial growth is about 10%, and the remaining 90% is thermally decomposed into highly reactive radicals and discharged through the exhaust mechanism 40. This is the main cause of by-products.

  Silicon generated by the decomposition of trichlorosilane adheres to members exposed to high temperatures other than the surface of the silicon wafer 100, but this can be removed by introducing hydrogen chloride through the introduction mechanism 30. it can. However, in order to remove silicon deposits with hydrogen chloride, it is necessary to heat the inside of the chamber 20 to a temperature equivalent to that during epitaxial growth. This means that the removed silicon becomes radicals and adheres as a by-product at a location where the silicon is not sufficiently heated (for example, the exhaust mechanism 40).

  The introduction pipe 31, the collective introduction pipe 34, and the injection cap 32 are all made of a metal material, and the surface thereof is coated with quartz. Thereby, contamination of the silicon wafer 100 by the metal constituting the introduction pipe 31, the collective introduction pipe 34 and the injection cap 32 is prevented. The introduction pipe 31, the collective introduction pipe 34, and the injection cap 32 are members having a relatively complicated shape. However, as described above, quartz can be easily coated even on a complicated shape. In addition, since the introduction pipe 31, the collective introduction pipe 34, and the injection cap 32 are members to which less by-products are attached, there is little need for cleaning using hydrofluoric acid.

  As shown in FIG. 1, the exhaust mechanism 40 includes an exhaust pipe 41 and an exhaust cap 42 that connects the base plate 29 and the exhaust pipe 41. The exhaust pipe 41 is a pipe connected to the collective exhaust pipe 44 via the valve 43. Therefore, the gas exhausted from the chamber 20 is exhausted to the collective exhaust pipe 44 via the exhaust cap 42 and the exhaust pipe 41. During maintenance, the valve 43 is closed. In this state, the exhaust pipe 41 and the exhaust cap 42 are removed and cleaned. Therefore, the exhaust pipe 41 is defined as a pipe upstream of the valve 43 that defines the boundary with the collective exhaust pipe 44.

  As described above, since most of the process gas trichlorosilane is thermally decomposed without contributing to epitaxial growth or silicon-derived radicals removed by hydrogen chloride are exhausted, the temperature of the gas is increased. Polymerization occurs in the exhaust mechanism 40 that rapidly decreases to form SinHxCly, which is a by-product. For this reason, by-products are gradually accumulated on the inner wall of the exhaust pipe 41 and the like, thereby obstructing the gas flow and serving as a particle generation source. Therefore, accumulated by-products must be removed by regular maintenance. At the time of maintenance, since the exhaust mechanism 40 is removed from the chamber 30 and released to the atmosphere, the attached by-products take in oxygen and moisture in the atmosphere and form polysiloxane and the like.

  The exhaust pipe 41 and the exhaust cap 42 are both made of a metal material, and the surface thereof is coated with DLC. Thereby, contamination of the silicon wafer 100 by the metal constituting the exhaust pipe 41 and the exhaust cap 42 is prevented. As described above, the exhaust pipe 41 and the exhaust cap 42 are regions in which the temperature of the gas is drastically lowered, and therefore, by-products are extremely attached. For this reason, at the time of maintenance, it is necessary to remove by-products such as polysiloxane by washing with a liquid containing hydrofluoric acid. In this embodiment, these surfaces are subjected to DLC coating. Therefore, the coating is not attacked even if a liquid containing hydrofluoric acid is used. The heat resistance temperature of the DLC coating is lower than that of the quartz coating. However, since the exhaust pipe 41 and the exhaust cap 42 are not exposed to as much heat as the slit valve 27 and the base plate 29, the DLC coating may deteriorate due to heat. Absent.

  As described above, the epitaxial growth apparatus 10 according to the present embodiment uses a liquid containing hydrofluoric acid for the exhaust pipe 41 and the exhaust cap 42 to which a large amount of by-products adhere among a plurality of members made of a metal material. DLC coating that can be maintained is applied, and other members to which by-products do not adhere so much have high heat resistance, and quartz coating that can cope with complex shapes is applied. As a result, it is possible to easily remove the by-product by regular maintenance while preventing contamination of the silicon wafer 100 with metal.

  In addition, since the surface on which the DLC coating is applied is superior in smoothness to the surface on which the quartz coating is applied, the effect of reducing the amount of by-products attached to the exhaust mechanism 40 is also obtained. This also makes it possible to lengthen the maintenance cycle.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

  For example, in the above embodiment, DLC coating is applied to the exhaust pipe 41 and the exhaust cap 42. However, the coating material is not limited to DLC, and metal contamination can be prevented and hydrofluoric acid can be used. Other materials can be used as long as they are not attacked.

  Moreover, in the said embodiment, although the exhaust piping 41 and the exhaust cap 42 are selected as a member which performs DLC coating, this invention is not limited to this. In other words, since the amount and site of by-product attachment vary depending on the type and structure of the device, a member to be subjected to DLC coating may be appropriately selected according to the type and structure of the device.

  Moreover, although the epitaxial growth apparatus was mentioned as an example in the said embodiment, the object of this invention is not limited to this. Accordingly, the present invention can be applied to other types of silicon wafer processing apparatuses such as a CVD apparatus, a sputtering apparatus, and a dry etching apparatus.

10 Silicon wafer processing equipment (epitaxial growth equipment)
20 Chamber 21 Upper member 22 Lower member 23, 24 Side member 25 Susceptor 26 Elevating mechanism 27 Slit valve 28 Rotating shaft 28a Rotating housing 28b Wafer lift housing 28c Collet 28d Isolation housing 29 Base plate 30 Introducing mechanism 31 Introducing piping 32 Injecting cap 32 33 Flow control valve 34 Collective introduction pipe 35 Main valve 36 Main introduction pipe 40 Exhaust mechanism 41 Exhaust pipe 42 Exhaust cap 43 Valve 44 Collective exhaust pipe 50 Motor 60 Actuator 100 Silicon wafer

Claims (5)

A chamber in which a silicon wafer is accommodated and a predetermined process is performed by the introduced gas;
A silicon wafer processing apparatus comprising: a plurality of members attached to the chamber and made of a material containing metal,
The plurality of members include an exhaust mechanism that guides gas exhausted from the chamber, and a base plate that holds the chamber,
An apparatus for processing a silicon wafer, wherein a first coating made of DLC is applied to at least a part of the exhaust mechanism, and a second coating made of quartz is applied to the base plate . Wherein the plurality of members are further comprise introducing mechanism for introducing a gas into the chamber, to claim 1 where at least a portion of the introducing mechanism is characterized in that the second coating is applied The silicon wafer processing apparatus as described. The exhaust mechanism includes an exhaust pipe, an exhaust cap that connects the base plate and the exhaust pipe,
The introduction mechanism includes an introduction pipe, and an injection cap that connects the base plate and the introduction pipe.
The exhaust pipe and the exhaust cap are both provided with the first coating,
The silicon wafer processing apparatus according to claim 2 , wherein the introduction pipe and the injection cap are both coated with the second coating. The plurality of members further include a slit valve for loading the silicon wafer into the chamber or unloading the silicon wafer from the chamber, and the second coating is applied to the slit valve. The silicon wafer processing apparatus according to claim 1 , wherein the silicon wafer processing apparatus is provided. The plurality of members further include a rotation shaft insertion portion for rotating the silicon wafer in the chamber, and the rotation shaft insertion portion is provided with the second coating. The silicon wafer processing apparatus according to any one of claims 1 to 4 .

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