JP2005203482A - Heat treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment apparatus which can prevent the breaking of a placing plate in contact with a substrate and thereby can suppress the slip or other problems of the substrate during heat treatment. <P>SOLUTION: A supporting tool 30 comprises a main part 56 and the placing plate 58. The main part 56 is made of silicon carbide or silicon carbide impregnated with silicon, and comprises, for example, four struts 60 and connecting sections 62, each connecting the two facing struts 60. The connecting sections 62 are formed in the form of an arm. The placing plate 58 is supported on the connecting sections 62, and the substrate 64 is placed on the placing plate 58. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat treatment apparatus for heat treating a semiconductor wafer, a glass substrate or the like.

  For example, when a substrate such as a plurality of silicon wafers is heat-treated using a vertical heat treatment furnace, a silicon carbide support (boat) is used. The support is provided with support grooves that support the substrate at, for example, three points.

  In this case, when the heat treatment is performed at a temperature of about 1000 ° C. or more, slip dislocation defects are generated in the substrate in the vicinity of the support groove, which causes a slip line. When a slip line occurs, the flatness of the substrate deteriorates. For these reasons, there is a problem in that it is difficult to manufacture an LSI having a desired pattern due to mask misalignment (focal misalignment or mask misalignment due to deformation) in a lithography process, which is one of important processes in the LSI manufacturing process. It has occurred.

  As means for solving such a problem, a technique is known in which a placement plate is first placed in a support groove, and a substrate to be processed is placed on the placement plate (see Patent Document 1). By changing from the conventional three-point support to the surface support by the mounting plate, the self-weight stress concentration of the substrate to be processed is suppressed, the substrate warpage is prevented, and the slip dislocation defect is prevented from occurring. To do.

JP 2000-223495 A

  However, conventionally, since the mounting plate is supported by, for example, three support grooves, the mounting plate is easily held unevenly, and if the mounting plate is held unevenly, the mounting plate is cracked. Problem has occurred.

  An object of the present invention is to provide a heat treatment apparatus that can prevent a substrate plate from coming into contact with a substrate and suppress a substrate slip or the like that occurs during the heat treatment.

  In order to solve the above-mentioned problems, the present invention is characterized by having a reaction furnace for processing a substrate and a support for supporting the substrate in the reaction furnace, and the support includes a main body portion, a substrate, The main body has a plurality of support columns and a connection portion connecting these support columns, and the connection plate supports the mounting plate described above. Since the mounting plate is supported by the connection part connecting the support columns, the stress concentration generated on the mounting plate can be dispersed and reduced, and the mounting plate is less likely to break or the mounting plate. Dispersion / reduction of the stress concentration can reduce the deformation of the mounting plate, thereby suppressing the occurrence of slip on the substrate disposed on the mounting plate.

  Preferably, the connection part is in an arm shape, and at least two or more connection parts are provided.

  Preferably, the mounting plate has a disk shape having a diameter smaller than that of the substrate. As described above, when the mounting plate has a disk shape, the connection portion is a disk shape having a diameter larger than that of the substrate, and the disk-shaped connection portion is supported by the support groove formed in the support column. Also good. That is, when the mounting plate is the first plate and the connection portion is the second plate, the diameter is increased in the order of the first plate, the substrate, and the second plate. In this case, preferably, the connecting portion (second plate) is made of silicon carbide (SiC) or silicon carbide impregnated with silicon (Si).

  Preferably, the main body portion is made of silicon carbide (SiC) or silicon carbide impregnated with silicon (Si).

  Preferably, the mounting plate is made of silicon (Si). In particular, when the substrate is made of silicon, the substrate and the mounting plate are made of the same material, and thus have the same thermal expansion. Therefore, the occurrence of slippage of the substrate due to the difference in thermal expansion can be prevented.

  The heat treatment in the present invention is preferably performed at a high temperature of 1000 ° C. or higher, 1200 ° C. or higher, and further 1350 ° C. or higher.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a heat treatment apparatus 10 according to an embodiment of the present invention. The heat treatment apparatus 10 is, for example, a vertical type and includes a casing 12 in which a main part is arranged. A pod stage 14 is connected to the housing 12, and the pod 16 is conveyed to the pod stage 14. The pod 16 stores, for example, 25 substrates, and is set on the pod stage 14 with a lid (not shown) closed.

  In the housing 12, a pod transfer device 18 is disposed at a position facing the pod stage 14. Further, a pod shelf 20, a pod opener 22, and a substrate number detector 24 are arranged in the vicinity of the pod transfer device 18. The pod carrying device 18 carries the pod 16 among the pod stage 14, the pod shelf 20, and the pod opener 22. The pod opener 22 opens the lid of the pod 16, and the number of substrates in the pod 16 with the lid opened is detected by the substrate number detector 24.

  Further, a substrate transfer machine 26, a notch aligner 28, and a support tool 30 (boat) are disposed in the housing 12. The substrate transfer machine 26 has, for example, a tweezer 32 that can take out five substrates. By moving the tweezer 32, the pod placed at the position of the pod opener 22, the notch aligner 28, and the support 30. Transport the board with. The notch aligner 28 detects notches or orientation flats formed on the substrate and aligns the notches or orientation flats of the substrate at a certain position.

  In FIG. 2, a reactor 40 is shown. The reaction furnace 40 has a reaction tube 42, and the support 30 is inserted into the reaction tube 42. The lower part of the reaction tube 42 is opened to insert the support tool 30, and this open part is sealed with a seal cap 44. The periphery of the reaction tube 42 is covered with a soaking tube 46, and a heater 48 is disposed around the soaking tube 46. The thermocouple 50 is disposed between the reaction tube 42 and the soaking tube 46 so that the temperature in the reaction furnace 40 can be monitored. The reaction tube 42 is connected to an introduction tube 52 for introducing a processing gas and an exhaust tube 54 for exhausting the processing gas.

Next, the operation of the heat treatment apparatus 10 configured as described above will be described.
First, when a pod 16 containing a plurality of substrates is set on the pod stage 14, the pod 16 is transferred from the pod stage 14 to the pod shelf 20 by the pod transfer device 18 and stocked on the pod shelf 20. Next, the pod 16 stocked on the pod shelf 20 is transported and set to the pod opener 22 by the pod transport device 18, the lid of the pod 16 is opened by the pod opener 22, and the pod 16 is detected by the substrate number detector 24. The number of substrates accommodated in the sensor is detected.

  Next, the substrate is transferred from the pod 16 at the position of the pod opener 22 by the substrate transfer machine 26 and transferred to the notch aligner 28. The notch aligner 28 detects notches while rotating the substrates, and aligns the notches of the plurality of substrates at the same position based on the detected information. Next, the substrate is transferred from the notch aligner 28 by the substrate transfer machine 26 and transferred to the support 30.

  In this way, when one batch of substrates is transferred to the support tool 30, for example, the support tool 30 loaded with a plurality of substrates is loaded into the reaction furnace 40 set to a temperature of about 700 ° C. The inside of the reaction tube 42 is sealed with a seal cap 44. Next, the furnace temperature is raised to the heat treatment temperature, and the processing gas is introduced from the introduction pipe 52. The processing gas includes nitrogen, argon, hydrogen, oxygen, and the like. When heat-treating the substrate, the substrate is heated to a temperature of about 1000 ° C. or more, for example. During this time, the substrate is heat-treated according to a preset temperature rise and heat treatment program while monitoring the temperature in the reaction tube 42 with the thermocouple 50.

  When the heat treatment of the substrate is completed, for example, after the temperature in the furnace is lowered to a temperature of about 700 ° C., the support 30 is unloaded from the reaction furnace 40 and is supported until all the substrates supported by the support 30 are cooled. The tool 30 is put on standby at a predetermined position. Even when the temperature in the furnace is lowered, the temperature is lowered according to a preset temperature drop program while monitoring the temperature in the reaction tube 42 by the thermocouple 50. Next, when the substrate of the support 30 that has been waiting is cooled to a predetermined temperature, the substrate transfer machine 26 takes out the substrate from the support 30 and transports it to the empty pod 16 set in the pod opener 22. And accommodate. Next, the pod carrying device 18 carries the pod 16 containing the substrate to the pod shelf 20 and further to the pod stage 14 to complete.

Next, the support 30 will be described in detail.
In FIG. 3, the support 30 is composed of a main body portion 56 and a placement plate 58. The main body portion 56 is made of silicon carbide or silicon carbide impregnated with silicon, and includes, for example, four struts 60 and a connection portion 62 that connects the two struts 60 facing each other. The four struts 60 are each provided in the vertical direction. The connecting portion 62 is formed in an arm shape, and connects one strut 60 and the other strut 60 facing each other in parallel so as to form a bridge, and the two connecting portions 62 are arranged in a parallel position. A plurality of sets of connecting portions 62 are provided in parallel with the support column 60.

The mounting plate 58 is formed in, for example, a disk shape made of silicon, and the mounting plate 58 is mounted on the connecting portion 62 by contacting the upper surfaces of the two connecting portions 62 whose lower surfaces are parallel to each other. Then, the lower surface of the substrate 64 comes into contact with the upper surface of the mounting plate 58 to place and support the substrate 64.
In addition, the shape of the mounting plate 58 does not need to be a disk shape as in this embodiment, and may be configured as an ellipse or a polygon. Further, the mounting plate 58 can also be fixed to the connecting portion 62.

  The diameter of the mounting plate 58 is smaller than the diameter of the substrate 64, that is, the upper surface of the mounting plate 58 has an area smaller than the area of the flat surface which is the lower surface of the substrate 64. Is supported by the mounting plate 58 with the peripheral edge of the The substrate 64 has a diameter of, for example, 300 mm. Therefore, the mounting plate 58 has a diameter of less than 300 mm, and is preferably about 100 mm to 250 mm (about 1/3 to 5/6 of the substrate outer diameter).

  Further, the mounting plate 58 is formed to be thicker than the substrate 64. The thickness of the substrate 64 is, for example, 700 μm. Therefore, the thickness of the mounting plate 58 exceeds 700 μm and can be up to 10 mm, and at least twice the thickness of the substrate 64, for example, 3 mm to 10 mm is preferable, 3 mm to 6 mm is more preferable, and 4 mm to 5 mm is more preferable.

  An adhesion preventing layer can be formed on the upper surface of the mounting plate 58. This adhesion preventing layer is formed by, for example, treating a silicon surface or depositing on the silicon surface by CVD or the like to form a silicon nitride film (SiN), a silicon carbide film (SiC), a silicon oxide film ( It is made of a material having excellent heat resistance and wear resistance such as SiO 2), glassy carbon, microcrystalline diamond, and the like, and prevents the mounting plate 58 and the substrate 64 from being bonded after the substrate 64 is processed. When the adhesion preventing layer is a silicon carbide film, the thickness of the film is preferably 0.1 μm to 50 μm. When the silicon carbide film is thickened, due to the difference in thermal expansion coefficient between silicon and silicon carbide, the silicon mounting plate 58 is pulled by the silicon carbide film and the deformation amount of the entire mounting plate increases. This large deformation may cause a slip in the substrate 64. On the other hand, when the thickness of the silicon carbide film is as described above, the amount by which the silicon mounting plate 58 is pulled by the silicon carbide film decreases, and the deformation amount of the entire mounting plate also decreases. That is, when the silicon carbide film is thinned, the stress due to the difference in thermal expansion coefficient between the mounting plate 58 and the film is reduced, the deformation amount of the entire mounting plate is reduced, and the thermal expansion coefficient of the entire mounting plate is originally This is close to the thermal expansion coefficient of silicon (substantially the same thermal expansion coefficient when the substrate is silicon), and can prevent slipping.

In the above embodiment, since the thickness of the mounting plate 58 is set to a predetermined thickness that is thicker than the thickness of the substrate 64 as described above, the rigidity of the mounting plate 58 can be increased. It is possible to suppress deformation of the mounting plate 58 due to temperature changes during temperature, temperature drop, heat treatment, substrate unloading, and the like. Thereby, it is possible to prevent the occurrence of slip to the substrate 64 due to the deformation of the mounting plate 58. Further, since the material of the mounting plate 58 is made of silicon, which is the same material as the substrate 64, that is, a material having the same thermal expansion coefficient and hardness as the silicon substrate 64, the substrate 64 and the mounting plate 58 with respect to temperature change. The difference between the thermal expansion and the thermal contraction of the substrate 64 can be eliminated, and even if a stress is generated at the contact point between the substrate 64 and the mounting plate 58, the stress is easily released, so that the substrate 64 is damaged. It becomes difficult to do. Thereby, it is possible to prevent the occurrence of slip to the substrate 64 due to the difference in thermal expansion coefficient and the difference in hardness between the substrate 64 and the mounting plate 58.
In the description of the above embodiment and examples, the case where the diameter (area) of the mounting plate is smaller than that of the substrate has been described, but the mounting plate diameter can be made larger than the substrate diameter. In this case, in order to ensure the rigidity of the mounting plate 58, it is necessary to further increase the thickness of the mounting plate 58.

  The portion of the substrate transfer machine that supports the substrate of the tweezer 32 is divided into two portions, and has a larger interval than the outer periphery of the mounting plate 58, and the outer peripheral portion of the plate 58 from the direction orthogonal to the connecting portion 62. Are inserted at a predetermined distance. That is, in order to transfer the substrate 64 to the support tool 30, first, the substrate 64 is supported by the tweezer 32 of the substrate transfer machine, and the substrate 64 in a state supported by the tweezer 32 is moved above the placement plate 58 by the tweezer 32. And the tweezer 32 is lowered to place the substrate 64 on the placement plate 58. Conversely, to remove the substrate 64 from the support 30, the tweezer 32 is inserted between the substrate 64 and the connecting portion 62, the tweezer 32 is raised, the substrate 64 is placed on the tweezer 32, and the tweezer 32 is loaded. The placed substrate 64 is retracted by the tweezer 32.

  In FIG. 4, another embodiment according to the present invention is shown. The main body 56 has, for example, three struts 60, and support struts 68 are formed in the respective struts 60 at a predetermined interval in the vertical direction. The corresponding support grooves 68 of the three columns 60 are formed in parallel positions to form a set of support grooves 68, and a number of sets of the support grooves 68 are provided in the vertical direction. Each set of support grooves 68 supports a connection portion (second plate) 62, and three support columns 60 are connected via the connection portion 62. Connection portion 62 is made of silicon carbide or silicon carbide impregnated with silicon, and is made of a disk having a diameter larger than that of substrate 64. As in the above-described embodiment, a silicon mounting plate (first plate) 58 is mounted on the connection portion 62. Therefore, in this embodiment, the diameter increases in the order of the mounting plate (first plate) 58, the substrate 64, and the connection portion (second plate) 62. The tweezer 32 of the substrate transfer machine is inserted into a space surrounded by the placement plate (first plate) 58, the substrate 64, and the connection portion (second plate) 62.

  The heat treatment apparatus of the present invention can also be applied to a substrate manufacturing process.

  An example in which the heat treatment apparatus of the present invention is applied to one step of a manufacturing process of a SIMOX (Separation by Implanted Oxygen) wafer which is a kind of SOI (Silicon On Insulator) wafer will be described.

  First, oxygen ions are implanted into the single crystal silicon wafer by an ion implantation apparatus or the like. Thereafter, the wafer into which oxygen ions are implanted is annealed at a high temperature of 1300 ° C. to 1400 ° C., for example, 1350 ° C. or more, for example, in an Ar, O 2 atmosphere using the heat treatment apparatus of the above embodiment. By these processes, a SIMOX wafer in which a SiO 2 layer is formed inside the wafer (an SiO 2 layer is embedded) is produced.

  In addition to the SIMOX wafer, the heat treatment apparatus of the present invention can be applied to one step of the manufacturing process of the hydrogen anneal wafer. In this case, the wafer is annealed at a high temperature of about 1200 ° C. or higher in a hydrogen atmosphere using the heat treatment apparatus of the present invention. As a result, crystal defects in the wafer surface layer on which an IC (integrated circuit) is formed can be reduced, and crystal integrity can be improved.

  In addition, the heat treatment apparatus of the present invention can be applied to one step of the epitaxial wafer manufacturing process.

  Even when high-temperature annealing is performed as one step of the substrate manufacturing process as described above, by using the heat treatment apparatus of the present invention, the generation and deformation of the mounting plate on which the substrate is mounted are reduced. In addition, the occurrence of substrate slip can be prevented.

The heat treatment apparatus of the present invention can also be applied to a semiconductor device manufacturing process.
In particular, a heat treatment process performed at a relatively high temperature, for example, a thermal oxidation process such as wet oxidation, dry oxidation, hydrogen combustion oxidation (pyrogenic oxidation), HCl oxidation, boron (B), phosphorus (P), arsenic (As ), An antimony (Sb) or other impurity (dopant) is preferably applied to a thermal diffusion process for diffusing the semiconductor thin film.
Even in the case of performing a heat treatment step as one step of the manufacturing process of such a semiconductor device, the use of the heat treatment apparatus of the present invention reduces the occurrence of cracks and deformation of the mounting plate on which the substrate is mounted. The occurrence of slippage can be prevented.

The substrate processing apparatus of the present invention can also be applied to a semiconductor device manufacturing process.
In particular, a heat treatment process performed at a relatively high temperature, for example, a thermal oxidation process such as wet oxidation, dry oxidation, hydrogen combustion oxidation (pyrogenic oxidation), HCl oxidation, boron (B), phosphorus (P), arsenic (As ), An antimony (Sb) or other impurity (dopant) is preferably applied to a thermal diffusion process for diffusing the semiconductor thin film.
Even in the case of performing a heat treatment step as one step of the manufacturing process of such a semiconductor device, the use of the heat treatment apparatus of the present invention reduces the occurrence of cracks and deformation of the mounting plate on which the substrate is mounted. The occurrence of slippage can be prevented.

  The present invention can be used in a substrate heat treatment apparatus that is heat-treated at a high temperature.

As described above, the present invention is characterized by the matters described in the claims, and further includes the following embodiments.
(1) A reaction furnace for processing a substrate and a support for supporting the substrate in the reaction furnace, the support being in contact with the main body having a support and the substrate, and having a diameter smaller than that of the substrate. And a second plate that is supported by the column of the main body, supports the first plate, and has a diameter larger than that of the substrate.
(2) A step of carrying the substrate into the reaction furnace, a step of supporting the substrate at a connection part connecting a plurality of support columns, a step of processing the substrate in the reaction furnace, and a substrate after the treatment being carried out from the reaction furnace A substrate manufacturing method, a substrate processing method, or a semiconductor device manufacturing method.

1 is a perspective view showing a substrate processing apparatus according to an embodiment of the present invention. It is sectional drawing which shows the reaction furnace used for the substrate processing apparatus which concerns on embodiment of this invention. The support which concerns on embodiment of this invention is shown, (a) is a front view, (b) is the sectional view on the AA line of (a), (c) is a perspective view. The support which concerns on other embodiment of this invention is shown, (a) is a front view, (b) is the sectional view on the AA line of (a), (c) is a perspective view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Heat processing apparatus 30 Support tool 32 Tweezer 56 Main-body part 58 Mounting plate (1st plate)
60 support 62 connection part (second plate)
64 substrates

Claims (1)

A reactor for processing substrates;
A support for supporting the substrate in the reactor,
The support has a main body and a mounting plate that comes into contact with the substrate, and the main body has a plurality of support columns and a connection portion that connects the support columns, and the connection plate includes the mounting plate described above. A heat treatment apparatus characterized by being supported.

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