JP5355607B2 - Semiconductor manufacturing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing apparatus which inhibits powder particles from occurring when cleaning inside a vertical reaction furnace by using a cleaning gas or during deposition. <P>SOLUTION: According to an embodiment, a semiconductor manufacturing apparatus comprises: a vertically movable rotation structure including a lower connection part 5 fixed to a rotation axis of a motor 6, an upper connection part 4 fixed on the lower connection part 5 and a boat 2 fixed on the upper connection part 4 for supporting a processing target substrate 10; and a reaction tube 1 forming a reaction chamber housing the rotation structure. The upper connection part 4 is composed of a material having a coefficient of thermal expansion between a coefficient of thermal expansion of the lower connection part 5 and a coefficient of thermal expansion of the boat 2. The upper connection part 4 is coated with a coating film having corrosion resistance against a cleaning gas and a reaction gas used in the processing chamber. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  Embodiments described herein relate generally to a semiconductor manufacturing apparatus.

  For semiconductor manufacturing equipment equipped with a vertical reactor, all parts of the reactor that come into contact with the reaction gas are made of quartz, which allows the use of highly corrosive gases, such as tube cleaning with halogen-based cleaning gases. It is said. In this type of semiconductor manufacturing apparatus, a boat on which a plurality of silicon substrates, which are substrates to be processed, are mounted is also formed from quartz. On the other hand, the rotating plate of the rotary motor for rotating the boat in the reaction furnace is configured using a metal material such as stainless steel. During the film formation, the inside of the reaction furnace is heated to several hundred degrees Celsius. Therefore, the thermal expansion coefficient is reduced by interposing a ceramic member having a thermal expansion coefficient between the quartz boat and the stainless steel rotating plate as an intermediate material between the quartz boat and the stainless steel rotating plate. This prevents the quartz boat from being damaged. As the intermediate material, a silicon nitride sintered body is often used.

  One of the applications of the vertical reactor is a silicon nitride film forming process, in which the silicon nitride film is removed from the reactor wall by using a halogen-based gas as tube cleaning. However, this cleaning gas can remove the silicon nitride film, but also etches the intermediate material formed of the sintered body of silicon nitride, and the member that is the sintered body peels off, so that the semiconductor It becomes a source of dust generation that generates powdery particles that can cause device failure.

JP-A-6-151396

  An object of one embodiment is to provide a semiconductor manufacturing apparatus that prevents powder particles from being generated when the inside of a vertical reactor is cleaned using a cleaning gas or during film formation.

  According to one embodiment, a lower connecting portion fixed to the rotating shaft of the motor, an upper connecting portion fixed on the lower connecting portion, and a boat fixed on the upper connecting portion and supporting the substrate to be processed. And a reaction chamber forming portion that forms a reaction chamber that accommodates the rotation structure, and the upper connection portion is intermediate between the thermal expansion coefficient of the lower connection portion and the thermal expansion coefficient of the boat. This is a semiconductor manufacturing apparatus composed of a material having a coefficient of thermal expansion. The upper connection portion is coated with a cleaning gas used in the reaction chamber and a coating film having corrosion resistance against the reaction gas.

FIG. 1 is a cross-sectional view schematically showing the configuration of the semiconductor manufacturing apparatus according to the first embodiment. FIG. 2 is a diagram illustrating the semiconductor manufacturing apparatus in a state where the elevator is lowered. FIG. 3 is a diagram showing a rotating shaft structure of a vertical reactor.

  Exemplary embodiments of a semiconductor manufacturing apparatus will be explained below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment.

(First embodiment)
FIG. 1 is a cross-sectional view schematically showing the configuration of the semiconductor manufacturing apparatus according to the first embodiment. The semiconductor manufacturing apparatus includes a vertical reaction furnace including a reaction tube 1, a boat 2, a boat cap 3, an upper connection portion 4, a lower connection portion 5, a motor 6, an elevator 7, and a heater 8. The vertical reaction furnace is an apparatus that accommodates a plurality of substrates to be processed 10 mounted on a boat 2 in a cylindrical reaction tube 1 and supplies a reaction gas into the reaction tube 1 to perform a film forming process. . The reaction tube 1 and the boat cap 3 constitute a reaction chamber forming portion that forms a reaction chamber. The reaction tube 1, the boat 2, and the boat cap 3 are formed of a material that is not corroded by the reaction gas or the cleaning gas (in other words, has low reactivity with the reaction gas or the cleaning gas). For example, the reaction tube 1, the boat 2, and the boat cap 3 are formed using, for example, quartz as a material when the reaction gas is a silane-based gas such as dichlorosilane or silane and the cleaning gas is a halogen-based gas.

  The boat 2 includes a base portion 2a and a support pillar portion 2b, and the substrate to be processed 10 is set on the support pillar portion 2b. The base 2 a of the boat 2 is connected to the lower connection 5 connected to the shaft of the motor 6 via the upper connection 4, and rotates in the reaction tube 1 by driving the motor 6. Thereby, the temperature non-uniformity in the circumferential direction and the non-uniformity of gas concentration in the reaction furnace are alleviated, and the film thickness and quality are made uniform in the rotation direction. The lower connecting portion 5 fixed to the rotating shaft of the motor 6 is made of a metal such as stainless steel like the rotating shaft of the motor 6, and connects and fixes the lower connecting portion 5 made of metal and the boat 2 made of quartz. The upper connection portion 4 is made of a ceramic member which is a sintered body of silicon nitride having a thermal expansion coefficient intermediate between the two.

  FIG. 2 is a view showing the semiconductor manufacturing apparatus with the elevator 7 lowered. As shown in FIG. 2, the motor 6 can be moved up and down by a support arm of the elevator 7, and the motor 6, the boat cap 3, the lower connection portion 5, the upper connection portion 4, and the boat 2 are moved up and down by the elevator 7. Is moved up and down.

  The substrate 10 to be processed is placed on the boat 2 in a room temperature environment with the elevator 7 lowered, and then loaded into the reaction tube 1 as the elevator 7 rises (see FIG. 1). During the film forming process, the inside of the reaction furnace is heated to about 200 to 1000 ° C. by the heater 8. After the film forming process, the elevator 7 is lowered to unload the substrate 10 to be processed from the reaction tube 1, and the substrate 10 having been formed is lowered from the boat 2 in a room temperature environment. For this reason, stress acts on the boat 2, the upper connection portion 4, and the lower connection portion 5 according to the difference in the respective thermal expansion coefficients. However, the upper connecting portion 4 disposed between the quartz boat 2 and the lower connecting portion 5 made of metal (stainless steel) is composed of a silicon nitride sintered body having a thermal expansion coefficient intermediate between quartz and stainless steel. Therefore, thermal stress is relieved. The general linear expansion coefficient of each material is about 0.6 for quartz, about 18 for stainless steel, and about 3.5 for silicon nitride.

  The boat cap 3 is cooled during the film forming process, and the heat of the lower connection portion 5 is absorbed by the boat cap 3. For this reason, the lower connecting portion 5 is cooler than the boat 2 during the film forming process. When the lower connecting portion 5 having a large coefficient of thermal expansion becomes lower in temperature than the boat 2, the difference in expansion amount is alleviated.

  FIG. 3 is a view showing a rotating shaft structure of a vertical reactor. The rotating shaft 61 of the motor 6 is connected to the lower connecting portion 5 via the magnetic seal 9, and airtightness is maintained at a portion where the rotating shaft 61 of the motor 6 penetrates the boat cap 3.

A purge gas inlet 31 is provided at the lower portion of the boat cap 3, and purge gas (for example, N ₂ gas) supplied from a purge gas supply device 11 provided outside the vertical reactor is discharged into the furnace. The purge gas released into the furnace flows toward the reaction tube 1 as indicated by a broken line arrow in FIG. This makes it difficult for the reaction gas and the cleaning gas to enter the vicinity of the upper connection portion 4 and the lower connection portion 5 during the film forming process and during the cleaning.

  The upper connecting portion 4 has a columnar shape having flanges 41 and 42 at upper and lower ends. A screw hole 43 is provided in the flange 42 at the lower end of the upper connecting portion 4. On the other hand, a screw hole 44 is provided in the flange 41 at the upper end of the upper connection portion 4. The upper connection portion 4 is connected and fixed to the base portion 2a of the boat 2 by a screw 21 or a pin at a plurality of locations by an upper flange 41. The fixing screw 21 for connecting the upper connecting portion 4 and the base portion 2a is made of alumina, for example.

  Further, the upper connecting portion 4 and the lower connecting portion 5 are connected and fixed at a plurality of locations by adjusting screws 51, and by adjusting the adjusting screw 51, the distance between the upper connecting portion 4 and the lower connecting portion 5, the base The interval between the portion 2a and the boat cap 3 (purge gas passage interval to the reaction chamber) can be adjusted. The adjusting screw 51 is made of, for example, stainless steel.

  As described above, the upper connecting portion 4 is fixed to the lower connecting portion 5 via the adjusting screw 51 and is fixed to the boat 2 via the fixing screw 21, so that the lower connecting portion 5 and the boat 2 are connected to each other. And the rotational force of the motor 6 is transmitted to the boat 2.

  One of the applications of the vertical reactor is a silicon nitride film forming process, in which the silicon nitride film is removed from the reactor wall by using a halogen-based gas as tube cleaning. However, this cleaning gas can remove the silicon nitride film, but also etches the upper connection portion 4 formed of a sintered body of silicon nitride, and the member that is the sintered body peels off. For this reason, the upper connection portion 4 formed of a silicon nitride sintered body serves as a dust generation source that generates powder particles that induce a defect in the semiconductor device to be manufactured. Note that the halogen-based gas may be a single gas or a mixed gas in which a halogen-based gas is mixed.

  Therefore, in the first embodiment, the upper connecting portion 4 has a reactive gas with respect to the entire outer surface of the silicon nitride sintered body constituting the main body and the screw hole into which the screw 21 and the adjusting screw 51 are inserted. Alternatively, a silicon oxide coating film 70 having corrosion resistance against the cleaning gas is formed. By coating the upper connecting portion 4 with silicon oxide by the CVD method, a silicon oxide film that is denser and has fewer defects than the sintered body can be formed. Although there are physical irregularities on the surface of the sintered body, the surface of the sintered body can be covered with a coating film without a gap by using a CVD method with a high step coverage. Thereby, the etching to the silicon nitride sintered body by the cleaning gas can be suppressed, and the generation of dust can be prevented. However, the surface of the upper connection portion 4 can be coated not only by the CVD method but also by the PVD method or the like.

  The thickness of the coating is, for example, about 0.1 to 3 μm. If the coating of silicon oxide is too thin, the effect of preventing corrosion of the upper connection portion 4 by the cleaning gas will be insufficient. On the other hand, if the coating of silicon oxide is too thick, the coating film cannot follow the thermal expansion of the upper connection portion 4 and cracks occur in the coating film, which causes a reduction in the anticorrosion effect. However, the above-described coating thickness is merely an example, and is not limited to this range.

  In the present embodiment, since the upper connecting portion 4 is coated with silicon oxide having corrosion resistance against the reaction gas or the cleaning gas, the upper connecting portion 4 is not corroded by the cleaning gas. Therefore, it is possible to prevent the powdery particles generated from the upper connection portion 4 during the cleaning of the reaction furnace from adhering to the substrate to be processed during the film formation and causing the film formation failure.

(Second Embodiment)
The semiconductor manufacturing apparatus according to the second embodiment has substantially the same configuration as that of the first embodiment. However, in this embodiment, the upper connection portion is coated with alumina (Al ₂ O ₃ ). Others are the same as in the first embodiment.

  Also in this embodiment, the upper connection portion is not corroded by the cleaning gas or the reaction gas. Accordingly, it is possible to prevent the formation of defective film formation due to the powdery particles generated from the upper connection part during the cleaning of the reaction furnace or during film formation adhering to the substrate to be processed during film formation.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  1 reaction tube, 2 boat, 3 boat cap, 4 upper connection part, 5 lower connection part, 6 motor, 10 substrate to be processed.

Claims (5)

A vertically connecting portion having a lower connecting portion fixed to a rotating shaft of a motor, an upper connecting portion fixed on the lower connecting portion, and a boat fixed on the upper connecting portion and supporting a substrate to be processed. Rotating structure,
A reaction chamber forming section for forming a reaction chamber for housing the rotating structure;
Comprising a material having an intermediate thermal expansion coefficient between the thermal expansion coefficient of the lower connection part and the thermal expansion coefficient of the boat,
The upper connection part is coated with a cleaning gas used in the reaction chamber and a coating film having corrosion resistance against the reaction gas,
The reaction chamber forming part and the boat are formed using quartz as a material ,
The lower connection part is made of metal,
The upper connecting portion, a semiconductor manufacturing apparatus characterized by being formed of silicon nitride.   The semiconductor manufacturing apparatus according to claim 1, wherein the coating film is a silicon oxide film. The semiconductor manufacturing apparatus according to claim 1, wherein the coating film is Al ₂ O ₃ .   The semiconductor manufacturing apparatus according to claim 1, wherein the coating film is a film formed by a CVD method. The cleaning gas is a gas containing a halogen gas,
The semiconductor manufacturing apparatus according to claim 1, wherein the reaction gas is a gas containing a silane-based gas.

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