JP2007073865A - Heat treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment device capable of surely preventing a thermal insulating material of a heater unit from falling. <P>SOLUTION: The heat treatment device has a reaction tube 42 for treating a substrate 54, a heater wire 72 arranged outside the reaction tube 42 and heating inside the reaction tube, a side-part thermal-insulating material 76 arranged outside the heater wire 72 and provided so as to cover the side part of the reaction tube 42, and an upper thermal-insulating material 78 arranged so as to be in contact with the upper end of the side-part thermal-insulating material 76 and provided so as to cover the upper part of the reaction tube 42. A positioning part 80 for positioning the upper thermal-insulating material 78 is provided to at least either of the side-part thermal-insulating material 76 and the upper thermal-insulating material 78. Stress relaxation treatment is applied to the positioning part 80. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  As this type of heat treatment apparatus, one having a reaction tube for processing a substrate and a heater unit for heating the inside of the reaction tube is widely used. For example, as a heater unit (heating device), one having a heater wire (heating wire) as a heating element and a heat insulating material (heat insulating material) is known (for example, Patent Document 1).

JP 2004-311775 A

  In addition, the heater unit includes, for example, a cylindrical side heat insulating material and a plate-shaped upper heat insulating material (top plate portion) made of a plurality of layers of heat insulating members provided with positioning step portions on the periphery. In addition, those having a structure in which an upper heat insulating material is placed on the side heat insulating material are known.

  However, when the heater unit having the above-described structure is subjected to thermal cycles of increasing and decreasing temperature many times, the heat insulating member may cause cracking or delamination, and the upper heat insulating material may collapse.

The collapse of the heat insulating material of the heater unit was considered to be caused by the following.
As shown in FIG. 5, when the substrate is processed, the furnace temperature is raised and lowered using a heater unit. By this thermal cycle, the heat insulating material repeats thermal expansion and contraction (FIG. 5A). In particular, the upper heat insulating member is covered with a casing made of a plate member such as SUS (Steel Use Stainless), for example, on the lowermost heat insulating member, and a plurality of layers of heat insulating members are placed on the heat insulating member. Yes. Therefore, during this thermal expansion, the heat insulating member is restrained from expanding upward and escapes downward (expands) together with the weight of the heat insulating material, so that the upper heat insulating material has a convex shape downward. (Dripping) (FIG. 5B). Moreover, although the inside of a furnace becomes high temperature because it is the same temperature as process temperature, since the upper part of an upper heat insulating material is insulated, it is colder than the lower part of this upper heat insulating material. Due to this temperature difference, a difference in thermal expansion occurs in the upper heat insulating material, and the upper heat insulating material becomes a convex shape downward (hangs down).

  At this time, a large stress is applied to the upper heat insulating material, and particularly those having corner portions such as the above-described positioning step portions are concentrated at the corner portions, and cracks, cracks, and the like are generated. Furthermore, when the thermal cycle is repeated many times, cracks and cracks grow and delamination occurs in the upper heat insulating material (FIG. 5C). Thereby, it is thought that an upper heat insulating material collapses.

  The objective of this invention is providing the heat processing apparatus which has a structure which prevents collapse of the heat insulating material of a heater unit.

  A feature of the present invention is that a reaction tube for processing a substrate, a heating element that is disposed outside the reaction tube and heats the inside of the reaction tube, and a side portion of the reaction tube that is disposed outside the heating element. A first heat insulating member provided so as to cover; and a second heat insulating member disposed so as to contact the upper end of the first heat insulating member and covering the upper part of the reaction tube. A positioning portion for positioning the second heat insulating member is provided on at least one of the first heat insulating member and the second heat insulating member, and stress relaxation processing is performed on the positioning portion. In the heat treatment equipment.

  Preferably, the positioning part is configured by providing a step part.

  Preferably, the corner portion of the step portion is rounded.

  Preferably, the second heat insulating member has a structure in which a plurality of layers of plate-like heat insulating materials are stacked, and each of the heat insulating materials of the plurality of layers is provided with a positioning portion for positioning each of the heat insulating materials. Stress relaxation treatment is performed.

  Preferably, at least a surface of the second heat insulating member facing the upper portion of the reaction tube is formed in a curved shape.

  Preferably, the second heat insulating member is provided with a vent for circulating quenching air.

  According to the present invention, since stress relaxation treatment is applied to at least one positioning portion of the first heat insulating member and the second heat insulating member, the stress concentration generated in the positioning portion is diffused, and thereby the heat insulating material of the heater unit. Can be reliably prevented.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a heat treatment apparatus 10 according to an embodiment of the present invention. This heat treatment apparatus 10 is a batch type vertical heat treatment apparatus, and has a casing 12 in which a main part is arranged. A pod stage 14 is connected to the front side of the housing 12, and the pod 16 is conveyed to the pod stage 14. For example, 25 wafers as substrates to be processed are stored in the pod 16 and set on the pod stage 14 with a lid (not shown) closed.

  A pod transfer device 18 is disposed on the front side in the housing 12 and 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 shelf 20 is disposed above the pod opener 22, and the substrate number detector 24 is disposed adjacent to the pod opener 22. 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 substrate support (boat) 30 are disposed in the housing 12. The substrate transfer machine 26 has, for example, an arm (tweezer) 32 that can take out five substrates. By moving this arm 32, the pod 16 placed at the position of the pod opener 22, the notch aligner 28, and The substrate is transported between the substrate supports 30. 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.

  Further, a reaction furnace 40 is disposed at the upper part on the back side in the housing 12. The substrate support 30 loaded with a plurality of substrates is carried into the reaction furnace 40 and subjected to heat treatment.

  An example of the reaction furnace 40 is shown in FIG. The reaction furnace 40 has a reaction tube 42 made of silicon carbide (SiC). The reaction tube 42 has a cylindrical shape in which the upper end is closed and the lower end is opened, and the opened lower end is formed in a flange shape. A quartz adapter 44 is disposed below the reaction tube 42 so as to support the reaction tube 42. The adapter 44 has a cylindrical shape with an open upper end and a lower end, and the open upper end and the lower end are formed in a flange shape. The lower surface of the lower end flange of the reaction tube 42 is in contact with the upper surface of the upper end flange of the adapter 44. A reaction vessel 43 is formed by the reaction tube 42 and the adapter 44. Further, a heater unit 46 to be described later is disposed around the reaction tube 42 excluding the adapter 44 in the reaction vessel 43.

  The lower part of the reaction vessel 43 formed by the reaction tube 42 and the adapter 44 is opened to insert the substrate support 30, and this open portion (furnace port) is an adapter with the furnace port seal cap 48 sandwiching the O-ring. It is made to seal by contacting the lower surface of the lower end flange of 44. The furnace port seal cap 48 supports the substrate support 30 and is provided so as to move up and down together with the substrate support 30. Between the furnace port seal cap 48 and the substrate support 30, a first heat insulating plate 52 made of quartz, and a second made of silicon carbide (SiC) disposed on the upper portion of the first heat insulating plate 52. A heat insulating plate 50 is provided. The substrate support 30 supports a large number of, for example, 25 to 100 substrates 54 in multiple stages with a gap in a substantially horizontal state, and is loaded into the reaction tube 42.

  In order to enable processing at a high temperature of 1200 ° C. or higher, the reaction tube 42 is made of silicon carbide (SiC). When the SiC reaction tube 42 is extended to the furnace port portion and the furnace port portion is sealed by the furnace port seal cap 48 via the O-ring, the heat transferred through the SiC reaction tube 42 is used. There is a possibility that the temperature of the seal portion becomes high and the O-ring that is a seal material is melted. If the seal part of the reaction tube 42 made of SiC is cooled so as not to melt the O-ring, the reaction tube 42 made of SiC is damaged due to a difference in thermal expansion due to a temperature difference. Therefore, a reaction region made of the heater unit 46 in the reaction vessel 43 is constituted by the reaction tube 42 made of SiC, and a portion outside the heating region made by the heater unit 46 is constituted by the adapter 44 made of quartz. Heat transfer from the tube 42 can be eased, and the furnace port can be sealed without melting the O-ring and without damaging the reaction tube 42. In addition, if the seal between the SiC reaction tube 42 and the quartz adapter 44 is improved in surface accuracy, the SiC reaction tube 42 is arranged in the heating region of the heater unit 46, so that there is a temperature difference. It does not occur and expands isotropically. Therefore, the flange portion at the lower end of the reaction tube 42 made of SiC can be kept flat, and no gap is formed between the adapter 44 and the sealing property can be obtained simply by placing the reaction tube 42 made of SiC on the adapter 44 made of quartz. Can be secured.

  The adapter 44 is provided with a gas supply port 56 and a gas exhaust port 59 integrally with the adapter 44. A gas introduction pipe 60 is connected to the gas supply port 56, and an exhaust pipe 62 is connected to the gas exhaust port 59.

  The inner wall of the adapter 44 is on the inner side (projects) from the inner wall of the reaction tube 42, and the side wall portion (thick portion) of the adapter 44 communicates with the gas supply port 56 and extends in the vertical direction. The nozzle mounting hole is provided in the upper part so as to open upward. The nozzle mounting hole is opened on the upper surface of the adapter 44 on the upper end flange side inside the reaction tube 42 and communicates with the gas supply port 56 and the gas introduction path 64. A nozzle 66 is inserted and fixed in the nozzle mounting hole. That is, the nozzle 66 is connected to the upper surface of the portion of the adapter 44 that protrudes inward from the inner wall of the reaction tube 42 in the reaction tube 42, and the nozzle 66 is supported by the upper surface of the adapter 44. With this configuration, the nozzle connection portion is not easily deformed by heat and is not easily damaged. Further, there is an advantage that the assembly and disassembly of the nozzle 66 and the adapter 44 are facilitated. The processing gas introduced from the gas introduction pipe 60 to the gas supply port 56 is supplied into the reaction pipe 42 through the gas introduction path 64 and the nozzle 66 provided in the side wall portion of the adapter 44. The nozzle 66 is configured to extend above the upper end of the substrate arrangement region along the inner wall of the reaction tube 42, that is, above the upper end of the substrate support 30.

Next, the operation of the heat treatment apparatus 10 configured as described above will be described.
In the following description, the operation of each part constituting the heat treatment apparatus 10 is controlled by the controller 70.

  First, when the pod 16 containing a plurality of substrates 54 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 54 accommodated in is detected.

  Next, the substrate transfer machine 26 takes out the substrate 54 from the pod 16 at the position of the pod opener 22 and transfers it to the notch aligner 28. In the notch aligner 28, the notch is detected while rotating the substrate 54, and the notches of the plurality of substrates 54 are aligned at the same position based on the detected information. Next, the substrate transfer machine 26 takes out the substrate 54 from the notch aligner 28 and transfers it to the substrate support 30.

In this way, when one batch of the substrates 54 is transferred to the substrate support 30, for example, a substrate in which a plurality of substrates 54 are loaded in the reaction furnace 40 (reaction vessel 43) set to a temperature of about 600 ° C. The support 30 is inserted, and the reactor 40 is sealed with a furnace port seal cap 48. Next, the furnace temperature is raised to the heat treatment temperature, and processing is performed in the reaction tube 42 from the gas introduction pipe 60 through the gas introduction port 56, the gas introduction path 64 provided in the side wall of the adapter 44, and the nozzle 66. Introduce gas. The processing gas includes nitrogen (N ₂ ), argon (Ar), hydrogen (H ₂ ), oxygen (O ₂ ), and the like. When the substrate 54 is heat-treated, the substrate 54 is heated to a temperature of, for example, about 1200 ° C. or higher.

  When the heat treatment of the substrate 54 is completed, for example, the temperature in the furnace is lowered to a temperature of about 600 ° C., and then the substrate support 30 supporting the heat-treated substrate 54 is unloaded from the reaction furnace 40 and supported by the substrate support 30. The substrate support 30 is put on standby at a predetermined position until all the substrates 54 that have been cooled are cooled. Next, when the substrate 54 of the substrate support 30 that has been put on standby is cooled to a predetermined temperature, the substrate transfer device 26 takes out the substrate 54 from the substrate support 30, and the empty pod set in the pod opener 22. It is conveyed to 16 and accommodated. Next, the pod transport device 18 transports the pod 16 containing the substrate 54 to the pod shelf 20 or the pod stage 14 to complete a series of processes.

Next, the heater unit 46 will be described in detail with reference to FIG.
As shown in FIG. 3, the heater unit 46 includes a heater wire (heating element) 72 and a heat insulating material 74. The heat insulating material 74 includes a side heat insulating material 76 as a first heat insulating member and an upper heat insulating material (top plate portion) 78 as a second heat insulating member.

  The heater wire 72 is disposed outside the reaction tube 42, and the heater tube 72 is heated to heat the inside of the reaction tube 42 (reaction vessel 43). The heater wire 72 is divided into a plurality of, for example, five zones.

  The side heat insulating material 76 is disposed outside the heater wire 72 and is provided so as to cover the side portion of the reaction tube 42. The side heat insulating material 76 is formed in a cylindrical shape with an upper end and a lower end opened, and an upper heat insulating material 78 is provided at the upper end of the side heat insulating material 76.

  The upper heat insulating material 78 is disposed so as to come into contact with the upper end portion of the side heat insulating material 76 and is provided so as to cover the upper portion of the reaction tube 42. The upper heat insulating material 78 has a structure in which plate-shaped (disk-shaped) heat insulating materials 78a to 78c are stacked in a plurality of layers (for example, three layers). Positioning portions 80 are provided in these multiple layers of heat insulating materials 78a to 78c. The positioning portion 80 is provided with step portions 80a to 80c. Each of these stepped portions 80a to 80c is provided in the peripheral portion of each of the plurality of layers of heat insulating materials 78a to 78c, and has a convex shape on the upper surface of the plurality of layers of heat insulating materials 78a to 78c. It is formed so that it may become concave shape in the lower surface of -78c. Therefore, each of the heat insulating materials 78a to 78c of the plurality of layers is positioned by engaging the step portions 80a to 80c of the heat insulating materials 78a to 78c of the plurality of layers.

  The positioning portion 80 of the upper heat insulating member 78 is subjected to stress relaxation processing. Specifically, the corner portion of the stepped portion 80c of the positioning portion 80 in the upper heat insulating member 78c is rounded (R cornering is applied to the corner portion). In this example, only the corner of the stepped portion 80c of the upper heat insulating member 78c is rounded, but the stepped portion 80a of the upper heat insulating material 78a and the corner of the stepped portion 80b of the upper heat insulating material 78b are also rounded. It may be rounded.

  Further, at least the surface of the upper heat insulating material 78 facing the upper portion of the reaction tube 42 (the lower surface of the upper heat insulating material 78) is formed in a curved surface (dome shape). In this example, only the lower surface of the upper heat insulating material 78 is formed in a curved shape, but the entire upper heat insulating material 78 may be formed in a curved shape, or may be formed in a conical shape or the like.

As described above, by applying stress relaxation processing to the positioning portion 80 for positioning the upper heat insulating material 78, stress concentration due to thermal expansion is dispersed, and cracking or delamination of the upper heat insulating material 78 is generated. Therefore, the heat insulating material 74 can be prevented from collapsing.
In addition, by forming the lower surface of the upper heat insulating material 78 in a curved shape, it is possible to reduce drooping (a state in which the upper heat insulating material 78 protrudes downward) due to thermal expansion or its own weight. Thereby, the bending force which acts on the upper heat insulating material 78 is relieved, and generation | occurrence | production of a crack, a crack, etc. can be suppressed.

  In the description of the above embodiment, the upper heat insulating material 78 provided with the stepped portion 80 is shown, but the present invention is not limited to this, and the side heat insulating material 76 and the upper heat insulating material 78 are not limited to this. It is only necessary that at least one of them is provided with a positioning portion 80 that has been subjected to stress relaxation processing for positioning the upper heat insulating material 78.

Next, a modification of the above-described heater unit 46 will be described with reference to FIG.
As shown in FIG. 4, the heater unit 46 in this example is provided with a vent 82 for circulating quenching air in the upper heat insulating material 78 of the heater unit 46. That is, the heater unit 46 has a structure in which a hole as a vent 82 is opened in the upper heat insulating material (top plate portion) 78 of the heater unit 46. By using the vent 82 to circulate quenching air from a cooling device (not shown) around the reaction tube 42, the inside of the reaction tube 42 (reaction vessel 43) is rapidly cooled.
Therefore, the heater unit 46 in this example can also be applied to a heat treatment apparatus having a cooling mechanism.

  In the description of the above embodiment, a batch-type heat treatment apparatus that heat-treats a plurality of substrates at a time is used. However, the present invention is not limited to this, and a single-wafer type may be used. Good.

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 higher, 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 the SiO ₂ layer is formed inside the wafer (the SiO ₂ layer is embedded) is manufactured.

  In addition to the SIMOX wafer, it is also possible to apply the heat treatment apparatus of the present invention to one step of a manufacturing process of a hydrogen anneal wafer or an Ar anneal wafer. In this case, the wafer is annealed at a high temperature of about 1200 ° C. or higher in a hydrogen atmosphere or an Ar 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.

  The heat treatment apparatus of the present invention can be applied even when a high temperature annealing process is performed as one process of the substrate manufacturing process as described above.

The heat treatment apparatus of the present invention can also be applied to a semiconductor device (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.

  The heat treatment apparatus of the present invention can also be used when performing the heat treatment step as one step of the semiconductor device manufacturing step.

  INDUSTRIAL APPLICABILITY The present invention can be used in a heat treatment apparatus for heat treating a semiconductor wafer, a glass substrate, or the like that needs to reliably prevent the heat insulating material of the heater unit from collapsing.

It is a perspective view which shows the heat processing apparatus which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the reaction furnace of the heat processing apparatus which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the heater unit of the heat processing apparatus which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the modification of the heater unit of the heat processing apparatus which concerns on embodiment of this invention. The progress of repeated thermal cycles in a heat treatment apparatus having a heater unit in which the step portion of the heat insulating member is not subjected to stress relaxation treatment is shown, (a) is a state in which the heat insulating member repeats thermal expansion and contraction, (b) Is a state where cracks and cracks have occurred in the heat insulating member, and (c) is a diagram showing a state in which delamination has occurred in the heat insulating member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Heat processing apparatus 42 Reaction tube 46 Heater unit 54 Substrate 72 Heater strand 76 Side heat insulating material 78 Upper heat insulating material 80 Positioning part 80a-80c Step part 82 Vent

Claims (1)

A reaction tube for processing the substrate;
A heating element that is disposed outside the reaction tube and heats the inside of the reaction tube;
A first heat insulating member disposed outside the heating element and provided to cover a side portion of the reaction tube;
A second heat insulating member disposed so as to be in contact with the upper end of the first heat insulating member and provided to cover an upper portion of the reaction tube;
A positioning part for positioning the second heat insulating member is provided on at least one of the first heat insulating member and the second heat insulating member, and stress relaxation processing is performed on the positioning part. Heat treatment equipment.

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