JP6630146B2 - Substrate processing apparatus, semiconductor device manufacturing method, and heating unit - Google Patents

Description

  The present invention relates to a substrate processing apparatus, a method for manufacturing a semiconductor device, and a heating unit.

  As a substrate processing apparatus, there is a batch type substrate processing apparatus that processes a predetermined number of substrates at a time. In a batch type substrate processing apparatus, a predetermined number of substrates are held by a substrate holder, the substrate holder is carried into a processing chamber, and a processing gas is introduced into the processing chamber while the substrate is heated, thereby performing required processing. Be done.

  Conventionally, a substrate in a processing chamber is heated from the side by a heater provided so as to surround the processing chamber. However, in particular, the central portion of the substrate below the processing chamber is hardly heated, and the temperature is easily lowered. As a result, in the conventional substrate processing apparatus, there is a problem that it takes time to raise the temperature in the processing chamber, and the recovery time (temperature stabilization time) becomes longer.

Japanese Patent No. 3598032

  The present invention provides a technique capable of shortening the temperature stabilization time in a processing chamber.

According to the present invention,
A substrate holder for holding a plurality of substrates,
A heat insulating portion provided below the substrate holder,
A processing chamber for storing the substrate holder and processing the substrate,
A first heating unit installed around the processing chamber and configured to heat the processing chamber from a side;
A second heating unit provided in the processing chamber, between the substrate holder and the heat insulating unit,
The second heating unit includes:
A substantially annular heating section;
A hanging portion extending downward from the heat generating portion,
A technique is provided in which the heat generating portion is configured to fit in an annular region having a smaller diameter than the substrate.

  According to the present invention, an excellent effect that the temperature stabilization time in the processing chamber can be shortened is exhibited.

FIG. 2 is a side sectional view of a processing furnace of the substrate processing apparatus suitably used in the first embodiment of the present invention. FIG. 2 is a schematic configuration diagram illustrating a control system of the substrate processing apparatus of the present invention. (A) is a diagram illustrating a simulation result of a temperature distribution when the entire bottom region is heated at the same temperature, and (B) is a diagram illustrating a simulation result of a temperature distribution when the entire bottom region is heated at the same output. FIG. FIG. 6 is a diagram illustrating a simulation result of a temperature distribution when a bottom region in a substantially middle portion of a radius of a substrate is heated by the cap heater according to the first embodiment of the present invention. 6 is a graph showing a comparison of the in-plane temperature distribution of the lowermost substrate when the diameter of the cap heater is varied. A circle indicates a position where the cap heater 34 is provided. 6 is a graph showing a comparison of the maximum temperature difference of the in-plane temperature of the lowermost substrate when the diameter of the cap heater is changed. It is a top view which shows a cap heater and its peripheral part. It is a principal part enlarged side sectional view which shows the bottom area of a substrate processing apparatus. It is a principal part enlarged side sectional view which shows the bottom area of a substrate processing apparatus. It is a perspective view showing the cap heater concerning a 1st example. FIG. 2 is a top view illustrating the cap heater according to the first embodiment. It is a side view showing the cap heater concerning a 1st example. It is a front view showing the cap heater concerning a 1st example. It is a top view which shows the cap heater and its periphery which concern on the modification of the 1st Example of this invention. FIG. 6 is a top view illustrating a cap heater according to a second embodiment of the present invention and a peripheral portion thereof. FIG. 13 is a top view illustrating a cap heater according to a modification of the second embodiment of the present invention and a peripheral portion thereof. It is a top view showing a cap heater concerning a 3rd example of the present invention. It is a longitudinal section showing a cap heater concerning a 3rd example of the present invention. FIG. 1 is a schematic diagram showing a configuration of a substrate processing apparatus suitably used in a first embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the processing furnace 1 has a cylindrical side heater 2 as a first heating unit. Inside the side heater 2, a cylindrical reaction tube 5 made of a heat-resistant material such as quartz (SiO ₂ ) and having a closed upper end and an open lower end is arranged concentrically with the side heater 2. Is established.

  The reaction tube 5 defines a processing chamber 6 therein, and a boat 7 as a substrate holder is accommodated in the processing chamber 6. The boat 7 is configured to hold wafers 8 as substrates in a horizontal posture and vertically aligned in multiple stages. The boat 7 is made of, for example, quartz or silicon carbide.

  In the present embodiment, as shown in FIG. 19, the processing chamber 6 is divided into four regions of region 1, region 2, region 3, and region 4 from above. The side heater 2 is divided into first to fourth heaters so as to correspond to each area. A first heater 2A is provided around the region 1, a second heater 2B is provided around the region 2, a third heater 2C is provided around the region 3, and a fourth heater 2D is provided around the region 4 above. . In the processing chamber 6, the boat 7 is stored in the areas 1 to 3, and a heat insulating part 31 described later is stored in the area 4. In order to heat the area (product area) in which the boat 7 is stored by the first heater to the third heater, the first heater to the third heater may be collectively referred to as an upper heater for heating the product area. Further, the fourth heater 2D may be referred to as a lower heater that heats the heat-insulating area because the fourth heater 2D heats the area above the area where the heat-insulating section 31 is housed (heat-insulating area).

  As shown in FIG. 1, a gas inlet 9 is provided at the lower end of the reaction tube 5 so as to penetrate the reaction tube 5. A nozzle 12 is connected to the gas introduction unit 9 as a gas introduction tube that is provided upright along the inner wall of the reaction tube 5. A plurality of gas introduction holes 16 are provided in a side surface of the nozzle 12 and facing the wafer 8, and a processing gas is introduced into the processing chamber 6 from the gas introduction holes 16.

  A source gas supply source, a carrier gas supply source, a reaction gas supply source, and an inert gas supply source (not shown) are connected to an upstream side of the gas introduction unit 9 via an MFC (mass flow controller) 14 as a gas flow controller. ing. A gas flow controller 15 is electrically connected to the MFC 14, and is configured to control at a desired timing so that the flow rate of the supplied gas becomes a desired amount.

  An exhaust unit 17 for exhausting the atmosphere in the processing chamber 6 is provided at a lower end of the reaction tube 5 at a position different from the gas introduction unit 9, and an exhaust pipe 18 is connected to the exhaust unit 17. A pressure sensor 19 as a pressure detector (pressure detector) for detecting the pressure in the processing chamber 6 is installed in the exhaust pipe 18, and an APC (Auto Pressure Controller) valve 21 as a pressure regulator (pressure regulator). Is connected to the vacuum pump 22 as a vacuum exhaust device.

  A pressure controller 23 is electrically connected to the APC valve 21 and the pressure sensor 19. The pressure controller 23 controls the pressure of the processing chamber 6 by the APC valve 21 based on the pressure detected by the pressure sensor 19. The APC valve 21 is configured to be controlled at a desired timing so as to obtain a desired pressure.

  At the lower end of the reaction tube 5, a base 24 as a holding member capable of airtightly closing the lower end opening of the reaction tube 5 and a seal cap 25 as a furnace cover are provided. The seal cap 25 is formed of, for example, a metal such as stainless steel. The base 24 formed in a disk shape is formed of, for example, quartz, and is mounted on the seal cap 25 so as to overlap. An O-ring 26 is provided on the upper surface of the base 24 as a seal member that contacts the lower end of the reaction tube 5. A rotation mechanism 27 for rotating the boat 7 is provided below the seal cap 25. A bottom plate 29 of the boat 7 is fixed to an upper end of a rotation shaft 28 of the rotation mechanism 27.

  A heat insulating part 31 is provided below the boat 7. The heat insulating portion 31 has a configuration in which the bottom plate 32 is sandwiched by a pressing plate 33 made of quartz. The bottom plate 32 is restrained between the pressing plates 33 so that the heat insulating portion 31 is prevented from falling. The heat insulating part 31 is formed in a cylindrical shape made of a heat-resistant material such as quartz or silicon carbide.

  Inside the heat insulating portion 31, a heat insulating plate (not shown) made of a heat resistant material such as quartz or silicon carbide is laminated. The internal heat insulating plate may be referred to as a heat insulating part 31. The fourth heater is configured to heat the upper part of the heat insulating part 31. With such a configuration, the upper part of the heat insulating portion 31 is heated, and the temperature controllability of the bottom region can be secured. On the other hand, the lower part of the heat insulating part 31 is not directly heated. Therefore, the heat from the side heater 2 and the cap heater 34 is insulated by the heat insulating portion 31, so that it is difficult for the heat to be transmitted to the furnace port on the lower end side of the reaction tube 5.

  A hole 30 is formed in the center of the heat insulating portion 31 so as to extend through the entire length in the vertical direction. The rotating shaft 28 is inserted into the hole 30, and the rotating shaft 28 penetrates through the seal cap 25 and the base 24 and is connected to the boat 7. The rotation of the rotation shaft 28 allows the boat 7 to rotate independently of the heat insulating portion 31.

  The seal cap 25 is configured to be vertically moved up and down by a boat elevator 35 as an elevating mechanism vertically installed outside the reaction tube 5, so that the boat 7 can be carried in and out of the processing chamber 6. It has become.

  In the space between the boat 7 and the heat insulating part 31, a cap heater 34 as a second heating part having a heat generating part 51 described later is provided. The cap heater 34 is installed so that the heat generating part 51 is located at least at a height equal to or higher than the height of the boundary between the third heater and the fourth heater. In other words, the cap heater 34 is installed so that the heat generating part 51 is located at least at a height equal to or higher than the height of the boundary between the product area and the heat insulating area. By disposing the cap heater 34 at such a position, it is possible to efficiently heat the lower part of the product area (the bottom area where the bottom wafer of the boat 7 is placed).

  The cap heater 34 has a structure in which, for example, a resistance heating element is hermetically sealed in a quartz tube as a protection tube. The heat generating portion 51 of the cap heater 34 is formed in a substantially annular shape in plan view. With such a configuration, in the bottom region, for example, the radial direction of the lowermost wafer 8 can be annularly heated. That is, a part of the lowermost wafer 8 in the radial direction can be mainly heated. In other words, a region outside the central region can be heated without heating the central region of the lowermost wafer 8. Note that the cap heater 34 only needs to have enough strength to withstand the pressure when the processing chamber 6 is depressurized, so that the thickness of the protective tube can be reduced, and the thickness in the vertical direction can be reduced.

  A first temperature sensor 37 as a first temperature detector is provided between the side heater 2 and the reaction tube 5. Further, a second temperature sensor 39 as a second temperature detector is provided so as to come into contact with the protective tube surface of the cap heater 34. Here, it is installed so as to contact the upper surface of the protection tube (see FIG. 7). The second temperature sensor 39 has a structure in which a temperature detector such as a thermocouple is housed in a protective tube.

  The temperature controller 38 adjusts the power supply to the side heater 2 based on the temperature information detected by the first temperature sensor 37, and supplies power to the cap heater 34 based on the temperature information detected by the second temperature sensor 39. By adjusting the condition, the side heater 2 and the cap heater 34 are controlled at a desired timing so that the temperature in the processing chamber 6 has a desired temperature distribution. The gas flow control unit 15, the pressure control unit 23, the drive control unit 36, and the temperature control unit 38 are electrically connected to a controller 42 as a main control unit that controls the entire substrate processing apparatus.

  As shown in FIG. 2, the controller 42, which is a control unit (control means), is configured as a computer including a CPU (Central Processing Unit) 43, a RAM (Random Access Memory) 44, a storage device 45, and an I / O port 46. Have been. The RAM 44, the storage device 45, and the I / O port 46 are configured to be able to exchange data with the CPU 43 via the internal bus 47. The controller 42 is connected to an input / output device 48 including, for example, a touch panel.

  The storage device 45 is configured by, for example, a flash memory, an HDD (Hard Disk Drive), or the like. In the storage device 45, a control program for controlling the operation of the substrate processing apparatus, a process recipe in which a procedure and conditions of the substrate processing described later are described, and the like are stored in a readable manner. The process recipe is a combination that allows the controller 42 to execute each procedure in the substrate processing described below and obtain a predetermined result, and functions as a program.

  Hereinafter, process recipes, control programs, and the like are collectively referred to as simply programs. In this specification, the use of the word program may include only a single recipe, only a single control program, or both. The RAM 44 is configured as a memory area (work area) in which programs, data, and the like read by the CPU 43 are temporarily stored.

  The I / O port 46 is connected to the above-described gas flow controller 15, pressure controller 23, drive controller 36, and temperature controller 38. The CPU 43 is configured to read and execute a control program from the storage device 45 and read a recipe from the storage device 45 in response to an operation command input from the input / output device 48 and the like. The CPU 43 adjusts the flow rate of various gases by the gas flow rate control unit 15, the pressure adjustment operation by the pressure control unit 23, the start and stop of the exhaust device 22, and the side unit by the temperature control unit 38 in accordance with the contents of the read recipe. The temperature control operation of the heater 2 and the cap heater 34, the rotation of the boat 7 by the drive control unit 36, the rotation speed adjustment operation, the elevating operation, and the like are controlled.

  The controller 42 is stored in an external storage device (for example, a magnetic tape, a magnetic disk such as a flexible disk and a hard disk, an optical disk such as a CD and a DVD, a magneto-optical disk such as an MO, and a semiconductor memory such as a USB memory and a memory card). The above-described program can be configured by installing the program on a computer. The storage device 45 and the external storage device 49 are configured as computer-readable recording media. Hereinafter, these are collectively simply referred to as a recording medium. In this specification, the term “recording medium” may include only the storage device 45 alone, may include only the external storage device 49 alone, or may include both. The provision of the program to the computer may be performed using communication means such as the Internet or a dedicated line without using the external storage device 49.

  Next, a substrate process (hereinafter, also referred to as a film forming process) for performing oxidation, diffusion, film formation, and the like on the wafer 8 is performed as one process of a semiconductor device manufacturing process using the processing furnace 1 having the above configuration. The method will be described. Here, an example in which a film is formed on the wafer 8 by alternately supplying the first processing gas (source gas) and the second processing gas (reaction gas) to the wafer 8 will be described. In the following description, the operation of each unit constituting the substrate processing apparatus is controlled by the controller 42.

  When a predetermined number of wafers 8 are loaded into the boat 7 (wafer charging), the boat 7 is loaded into the processing chamber 6 by the boat elevator 35 (boat loading). In this state, the seal cap 25 is in a state where the lower end opening (furnace opening) of the reaction tube 5 is hermetically closed via the base 24 and the O-ring 26. At this time, the cap heater 34 may be heated and maintained at a predetermined temperature (first temperature). In this case, the first temperature is set to a temperature lower than the temperature of the side heater 2 (at least, the temperature of the fourth heater).

  The inside of the processing chamber 6 is evacuated (reduced pressure) by the exhaust device 22 so as to have a desired pressure. At this time, the pressure in the processing chamber 6 is measured by the pressure sensor 19, and the APC valve 21 is feedback-controlled based on the measured pressure.

  Further, the wafer 8 in the processing chamber 6 is heated by the side heater 2 and the cap heater 34 so as to be at a desired temperature. At this time, the power supply to the side heater 2 is feedback-controlled based on the temperature information detected by the first temperature sensor 37 so that the inside of the processing chamber 6 has a desired temperature distribution. The degree of energization to the cap heater 34 is feedback-controlled based on the temperature information. At this time, the set temperature of the cap heater 34 is set to a temperature equal to or lower than the temperature of the side heater 2 (at least, the temperature of the fourth heater). Here, when the temperature of the wafer 8 in the bottom region in the processing chamber 6 reaches a desired temperature, the heating by the cap heater 34 may be stopped.

  Subsequently, the boat 7 is rotated by the rotation mechanism 27 via the bottom plate 29, so that the wafer 8 being processed is rotated. At this time, since the rotating shaft 28 is inserted through the hole 30, only the boat 7 rotates with respect to the heat insulating portion 31. The rotation of the boat 7 makes it possible to uniformly heat the bottom annular region even with the substantially annular cap heater 34.

(Source gas supply process)
Next, a source gas is supplied into the processing chamber 6 from a source gas supply source. The raw material gas is controlled by the MFC 14 to have a desired flow rate, flows through the nozzle 12 from the gas introduction unit 9, and is introduced into the processing chamber 6 from the gas introduction hole 16.

(Source gas exhaust process)
When a preset source gas supply time has elapsed, the supply of the source gas into the processing chamber 6 is stopped, and the processing chamber 6 is evacuated by the exhaust device 22. At this time, an inert gas may be supplied from the inert gas supply source into the processing chamber 6 (inert gas purge).

(Reaction gas supply process)
After the evacuation time set in advance, the reaction gas is supplied from the reaction gas supply source. The gas controlled to have a desired flow rate by the MFC 14 flows through the nozzle 12 from the gas introduction unit 9 and is introduced into the processing chamber 6 from the gas introduction hole 16.

(Reaction gas exhaust process)
Further, when a preset processing time elapses, the supply of the reaction gas into the processing chamber 6 is stopped, and the processing chamber 6 is evacuated by the exhaust device 22. At this time, an inert gas may be supplied from the inert gas supply source into the processing chamber 6 (inert gas purge).

  By performing the above-mentioned four steps non-simultaneously, that is, by performing a cycle that is performed without synchronization a predetermined number of times (n times), a film having a predetermined composition and a predetermined thickness can be formed on the wafer 8. Note that the above cycle is preferably repeated a plurality of times.

  After forming a film having a predetermined thickness, an inert gas is supplied from an inert gas supply source, the inside of the processing chamber 6 is replaced with the inert gas, and the pressure in the processing chamber 6 is returned to normal pressure. Thereafter, the seal cap 25 is lowered by the boat elevator 35, the furnace port is opened, and the processed wafer 8 is unloaded (boat unloaded) from the reaction tube 5 while being held by the boat 7. Thereafter, the processed wafer 8 is taken out of the boat 7 (wafer discharging). At this time, the heating by the cap heater 34 is stopped.

Up to one example, as a processing condition for forming an oxide film on the wafer 8 in the processing furnace 1 of the present embodiment, DCS (SiH ₂ Cl ₂ : dichlorosilane) gas is used as a source gas, and O ₂ is used as a reaction gas. When the (oxygen) gas and the N ₂ (nitrogen) gas are used as the inert gas, for example, the following are exemplified.
Processing temperature (wafer temperature): 300 ° C to 700 ° C,
Processing pressure (sub-pressure in the processing chamber) 1 Pa to 4000 Pa,
DCS gas: 100 sccm to 10000 sccm,
O ₂ gas: 100 sccm to 10000 sccm,
N ₂ gas: 100 sccm to 10000 sccm,
By setting each processing condition to a certain value within each range, it becomes possible to appropriately advance the film formation processing.

  Next, the relationship between the radial heating position of the cap heater 34 and the temperature distribution in the lower portion (bottom region) of the processing chamber 6 when the diameter of the wafer 8 is 300 mm, for example, will be described.

  FIGS. 3A and 3B show simulation results of the temperature distribution when the entire bottom region is heated (conventional example). As a case where the entire region of the bottom region was heated, a simulation was performed with a configuration in which a plurality of, for example, three cap heaters 34 were provided concentrically.

  FIG. 4 shows a simulation result of the temperature distribution when a part of the bottom region is annularly heated (the present invention). FIG. 4 shows, as an example, the temperature distribution when the heating position is 70 mm from the center of the processing chamber 6, that is, when the diameter of the cap heater 34 is 140 mm.

  As shown in FIGS. 3A and 3B, when the cap heaters 34a to 34c have the same temperature (615 ° C.) in the bottom region, the cap heaters 34a to 34c have the same output (12 W). In each case, the temperature distribution on the outer peripheral side of the bottom region was high and the temperature on the central side was low, and the in-plane temperature difference of the wafer 8 was about 4 ° C. at the maximum. That is, in the case of a heater configured to heat the entire bottom region, a large temperature difference occurs in the surface of the wafer 8, so that the in-plane uniformity of film formation may be deteriorated.

  On the other hand, as a result of intensive research, the inventors have found that the cap heater 34 heats not the entire bottom region but the annular region which is a part of the bottom region in the radial direction as shown in FIG. Has found that there is almost no temperature difference between the outer peripheral side and the central side of the bottom region, and it is possible to moderate the temperature distribution in the bottom region.

  As shown in FIGS. 5 and 6, when the heating position in the radial direction by the cap heater 34 (radius of the cap heater 34) is set to 90 mm and 110 mm from the center of the processing chamber 6, ie, the radius of the wafer 8a in the bottom region. When the outer peripheral side is heated more than the middle portion (75 mm), the in-plane temperature difference of the wafer 8a is smaller than that in the case where the entire bottom region is heated, which is improved. However, a temperature distribution occurs in which the temperature on the outer peripheral side of the lowermost wafer 8a is high and the temperature on the central side is low (see FIG. 5). Further, the maximum temperature difference in the plane of the wafer 8a is still large, and the in-plane temperature is not uniform (see FIG. 6). This is considered to be because the center side of the wafer 8a is hardly heated because there is no heat source on the center side of the wafer 8a, and the outer peripheral side of the wafer 8a is heated twice by the side heater 2 and the cap heater 34.

  Also, when the heating position in the radial direction by the cap heater 34 is set to 30 mm or 50 mm from the center of the processing chamber 6, that is, when heating the center side of the middle part of the radius of the wafer 8 a in the bottom area, As compared with the case where the entire area is heated, the in-plane temperature distribution of the wafer 8a is improved, but an inversely convex temperature distribution in which the temperature on the outer peripheral side and the central side becomes higher in the lowermost wafer 8a is generated. . Also in this case, the maximum temperature difference in the plane of the wafer 8a is still large, and the in-plane temperature is not uniform. It is considered that this is because the cap heater 34 was too close to the center side, resulting in insufficient heating of the wafer 8a in the vicinity of the radially intermediate portion.

  On the other hand, when the heating position by the cap heater 34 is 60 mm or more and 77.5 mm or less from the center of the processing chamber 6, that is, when the vicinity of the substantially middle part in the radial direction of the lowermost wafer 8 a is heated, There was almost no temperature difference between the outer peripheral side and the central side of the wafer 8a, and a gentle temperature distribution was obtained.

  Further, the temperature difference in the plane of the wafer 8a is about 0.6 ° C., and the in-plane temperature uniformity is improved. The reason why the maximum temperature difference in the plane of the wafer 8a is the smallest and the in-plane temperature uniformity is improved is, for example, that the heating position in the radial direction by the cap heater 34 is set at the center of the processing chamber 6 (of the wafer 8a). 77.5 mm from the center), that is, the diameter of the cap heater 34 is 155 mm, and the bottom region is heated.

  It should be noted that the in-plane temperature distribution is improved when the diameter of the cap heater 34 is set within the annular region of 60 mm or more and 180 mm or less as compared with the case where the entire bottom region is heated. In other words, the in-plane temperature distribution can be improved by heating around the center of the bottom region of the wafer 8a in the annular region having a diameter of 60 mm or more and 180 mm or less in the bottom region. If the diameter of the cap heater 34 is made to fall within the range of a circular area smaller than 60 mm, or if it is larger than 180 mm, the in-plane temperature difference becomes about 2.5 ° C., and the in-plane temperature distribution deteriorates. The in-plane uniformity of the film is impaired.

  Further, by setting the diameter of the cap heater 34 to 90 mm or more and 160 mm or less, the temperature difference in the surface of the wafer 8a could be made smaller than 2 ° C., and the temperature distribution was further improved. That is, by heating the inside of the annular region of the bottom region having a diameter of 90 mm or more and 160 mm or less, the temperature distribution can be further improved. Further, in order to further improve the in-plane uniformity in the substrate processing, the temperature difference in the plane of the wafer 8a is preferably within 0.6 ° C., and the diameter of the cap heater 34 is set to 120 mm or more and 155 mm or less. It is preferred that That is, it is preferable that the diameter of the cap heater 34 be set within the annular region of 120 mm to 155 mm so as to actively heat the annular region of the bottom region having a diameter of 120 mm to 155 mm.

  In the above description, for example, the diameter of the wafer is 300 mm. However, the same effect can be obtained even if the diameter of the wafer is not limited to 300 mm, for example, 150 mm, 200 mm, and 450 mm. That is, when the range of 1/5 or more and 3/5 or less of the bottom region with respect to the diameter of the wafer is positively heated, the in-plane temperature distribution is improved. That is, when the diameter of the cap heater 34 is set to be within the annular region of not less than 1/5 and not more than 3/5 of the diameter of the wafer, the in-plane temperature distribution can be improved. Preferably, when the range of 3/10 or more and 8/15 or less of the bottom region is positively heated, the in-plane temperature distribution can be further improved. That is, when the diameter of the cap heater 34 is set to be within the annular region of 3/10 or more and 8/15 or less of the diameter of the wafer, the in-plane temperature distribution can be further improved. More preferably, if the range of 2/5 or more and 31/60 or less of the bottom region is positively heated, the in-plane temperature distribution can be further improved, and the uniformity of substrate processing can be improved. In other words, when the diameter of the cap heater 34 is set within the annular region of 2/5 or more and 31/60 or less, the in-plane temperature distribution can be further improved, and the in-plane uniformity of the substrate processing can be improved. it can.

  As described above, in the process of moving the heating position in the radial direction by the cap heater 34 from the outer peripheral side of the bottom region to the center side, that is, the in-plane temperature of the lowermost wafer 8a is higher on the outer peripheral side, and The in-plane temperature of the lowermost wafer 8a is lower than the temperature distribution between the lower temperature distribution and the inversely convex temperature distribution in which the in-plane temperature of the lowermost wafer 8a is higher on the outer peripheral side and the center side and lower therebetween. There is a temperature distribution with almost no temperature difference between and the center side.

  Although there may be a difference depending on the apparatus or the like, there is a position where the in-plane temperature distribution of the lowermost wafer 8a becomes uniform when the radial heating position is changed from the outer peripheral side to the central side. . Therefore, the heating position at which the in-plane temperature distribution of the lowermost wafer 8a is uniform is determined by an experiment or the like, and the diameter of the cap heater 34 is determined so as to heat the determined heating position, thereby improving the uniformity of the substrate processing. be able to.

  Next, an example of the cap heater 34 in the first embodiment will be described with reference to FIGS. As shown in FIG. 7, the upper end of the cap heater 34 has a substantially annular heating portion 51 and a V-shaped reinforcing portion 52 protruding from both ends of the heating portion 51 toward the outer peripheral direction. Here, the heat generating portion 51 has a ring shape in which a part thereof is opened, in other words, is formed in an arc shape (a horseshoe shape). As shown in FIG. 8, the cap heater 34 has a hanging portion 53 that is bent at a root portion (outer end portion) of the reinforcing portion 52 and extends vertically downward.

  A first notch 54 is formed on the peripheral surface of the heat insulating portion 31 over the entire length in the vertical direction. The hanging portion 53 is inserted through the first notch portion 54, and the hanging portion 53 is prevented or almost prevented from projecting from the peripheral surface of the heat insulating portion 31. The hanging portion 53 passes through the base 24 and the seal cap 25 in an airtight manner, and is connected to a power supply unit (not shown). The penetrating portion of the hanging portion 53 is sealed by a predetermined sealing member such as a vacuum joint.

  The position where the first notch 54 is formed, that is, the position where the reinforcing portion 52 is formed, is above the gas exhaust portion 17, and the reinforcing portion 52 and the gas exhaust portion 17 have the same or substantially the same plane direction. Match.

  A plurality of spacers 55 are provided on the upper surface of the heat insulating portion 31 at a predetermined angle pitch between the heat generating portion 51 and the heat generating portion 51, and a gap is formed between the spacer 55 and the heat generating portion 51. The spacer 55 is formed of a heat insulating member such as quartz, and prevents the heat generating portion 51 from directly contacting the heat insulating portion 31 when the cap heater 34 is deformed due to aging.

  In addition, a second temperature sensor 39 such as a thermocouple is provided so that the tip portion contacts the upper surface of the heat generating portion 51. The position of the tip of the second temperature sensor 39 is fixed by a support section 56 which is a temperature measurement member support section provided on the heat generating section 51. The support portion 56 is further displaced by a predetermined angle, for example, 5 ° from a position 90 ° displaced from the root of the reinforcing portion 52 so that the contact length (contact area) between the heat generating portion 51 and the second temperature sensor 39 is increased. It is provided in the position where it did. Further, the relationship between the second temperature sensor 39 and the heat generating portion 51 is such that the center line of the second temperature sensor 39 is tangent or substantially imaginary with respect to a virtual circle (center circle) formed by the center line of the heat generating portion 51 in plan view. It is tangent.

  The base end side of the second temperature sensor 39 extends toward the peripheral portion of the heat insulating portion 31 and is bent vertically downward at the peripheral portion of the heat insulating portion 31. The bent portion is inserted into a second cutout portion 57 formed over the entire length of the heat insulating portion 31 in the vertical direction, and hermetically seals the base 24 and the seal cap 25 via a predetermined sealing member such as a vacuum joint. It penetrates and is electrically connected to the temperature control unit 38.

  The second temperature sensor 39, like the hanging portion 53 of the cap heater 34, is inserted through the second notch 57 so as not to protrude from the peripheral surface of the heat insulating portion 31.

  Next, the cap heater 34 will be described in detail with reference to FIGS. The V-shaped apex angle of the reinforcing portion 52 is, for example, 60 °. As shown in FIG. 10, assuming that the distance between the boundary between the heat generating portion 51 and the reinforcing portion 52 (the length of the bottom of the V-shape) is D1, the force applied to the boundary between the heat generating portion 51 and the reinforcing portion 52 is As for the moment M1 in the tangential direction with respect to the peripheral surface of the heat insulating portion 31, the reaction force generated by the distance D1 is reduced. Further, assuming that the projecting distance of the reinforcing portion 52 from the heat generating portion 51 (the distance from the center circle of the heat generating portion 51 to the top of the V-shape) is D2, a moment (radial moment) M2 in a direction away from the heat insulating portion 31. With regard to, the reaction force generated by the distance D2 is reduced.

  The cap heater 34 has a protection member 58 made of quartz, which is a frame having a circular cross section, and a conductive wire 59 inserted into the protection member 58. The conductive wire 59 is, for example, a one-turn nickel-made conductive wire. The conductive wire 59 forms a heating element, for example, a coil-shaped resistance heating element 61 in the heating section 51 with a boundary between the heating section 51 and the reinforcing section 52 as a heating point. The cap heater 34 generates heat.

  The conducting wires 59 inserted through the heat generating portion 51 are joined in the reinforcing portion 52 and are suspended in the hanging portion 53 in a bundled state. Further, the protective wires 62, which are insulating members, are attached to the conductive wires 59 in the reinforcing portions 52, respectively, and are insulated from each other by the protective glasses 62.

  The protective glass 62 is made of, for example, a plurality of connected cylindrical ceramic glasses. The conductive wires 59 are inserted into the ceramic glass, and the intervals between the connected ceramic glasses are reduced, so that the bundled conductive wires 59 are formed. The insulation between them is secured.

  In the hanging portion 53, only one of the bundled conductive wires 59 is inserted through the protective glass 62. If the diameter of the hanging portion 53 can be sufficiently ensured, both of the bundled conducting wires 59 may be inserted into the protective glass 62.

  The lower end of the hanging portion 53 is hermetically sealed and electrically insulated by a cap 63 formed of an insulating member such as silicon. That is, the resistance heating element 61 is hermetically sealed in the protection member 58 while being electrically insulated. The conducting wire 59 extends from the lower end of the hanging portion 53 in a state covered with an insulating member such as Teflon (registered trademark), and is connected to a power supply unit (not shown).

As described above, in the present embodiment, one or more effects described below can be obtained.
(A) Since the heat-generating portion of the cap heater is formed in an arc shape (horse-shoe shape) smaller than the diameter of the wafer, and the protection member of the cap heater is made of quartz having a small thickness, it is easy to raise and lower the temperature of the cap heater. Thus, the recovery time is shortened and the throughput can be improved.
(B) Since the diameter of the cap heater is smaller than the diameter of the wafer, the gas is uniformly supplied to the surface of the wafer without obstructing the flow of gas flowing from the gas introduction hole toward the gas exhaust portion. The in-plane uniformity of the wafer can be improved.
(C) Since the cap heater actively heats the annular region closer to the center than the peripheral edge of the lowermost wafer, the peripheral edge of the lowermost wafer is doubled by the side heater and the cap heater. , The bottom region where the temperature tends to decrease can be efficiently and uniformly heated, and the in-plane temperature uniformity of the wafer can be improved.
(D) The cap heater has a V-shaped reinforcing portion protruding from the heat generating portion to the outer peripheral side, and is bent downward from the root of the reinforcing portion to form a hanging portion, so that a separate reinforcing member is not provided. The strength of the cap heater can be ensured, and the number of components can be reduced.
(E) Since the reinforcing portion is located above the gas exhaust portion, even if turbulence occurs in the gas due to the V-shaped reinforcing portion, the turbulent flow can be quickly exhausted, and the generation of turbulent flow is suppressed. As a result, the gas is uniformly supplied to the wafer, and the in-plane uniformity can be improved.
(F) The hanging portion is inserted through the first cutout formed over the entire length of the heat insulating portion in the vertical direction, and the hanging portion does not project from the peripheral surface of the heat insulating portion. The obstruction of the flow can be prevented.
(G) In the hanging part, only one of the bundled conductors is inserted through the protective glass, so that the inner diameter of the hanging part can be reduced, and the space for the cap heater can be reduced. Can be.
(H) Since the cap heater is provided fixedly and the boat rotates independently of the cap heater, uneven heating of the wafer when using the cap heater is suppressed, and the wafer is uniformly heated. can do.
(I) Since the spacer is provided on the upper surface of the heat insulating portion, the cap heater is deformed by heat and does not come into direct contact with the heat insulating portion when it hangs down. Durability can be improved.
(J) The second temperature sensor is provided so as to be in contact with the upper surface of the heat generating portion of the cap heater, and the temperature of the cap heater can be measured from the side of the wafer to be heated. Thus, the heating controllability can be improved, and the in-plane uniformity of the wafer can be improved.
(K) Since the second temperature sensor is fixed by a support portion provided at a position further displaced by a predetermined angle from a position displaced by 90 ° from the root of the reinforcing portion, the second temperature sensor and the heat generating portion Thus, the quartz tube for protecting the thermocouple can be heated in a short time, the measurement error can be reduced, and the second temperature sensor can be easily positioned.
(L) By setting the heating position by the cap heater at or near the middle of the radius of the wafer, the temperature difference between the outer peripheral side and the central side in the bottom region in the processing chamber is reduced, and the bottom region is efficiently and uniformly formed. , And the in-plane uniformity of the temperature of the wafer can be further improved.
(M) By heating a portion where the temperature of the lower part of the processing chamber is apt to decrease by the cap heater, the soaking length can be extended to the lower part of the processing chamber, so that the number of dummy wafers can be reduced. That is, the number of processed product wafers can be increased, and productivity can be improved.

  FIG. 14 shows a modification of the first embodiment. In the modification, a cap heater 34 ′ having a smaller diameter than the cap heater 34 is provided concentrically with the cap heater 34. Since the structure of the cap heater 34 'is the same as that of the cap heater 34, the description is omitted.

  In the case of the modified example, the notch depth of the first notch portion 54 is increased, and the hanging portion 53 of the cap heater 34 (see FIG. 8) and the hanging portion (not shown) of the cap heater 34 'are both first cut. The penetrating portion can be provided without protruding from the peripheral surface of the heat insulating portion 31 by being inserted into the notch portion 54.

  By providing a plurality of cap heaters 34 in the annular region and controlling each of the cap heaters 34 individually, the heating controllability by the cap heater 34 is further improved, and the bottom region can be heated more effectively. In-plane temperature uniformity can be further improved. In FIG. 14, only one second temperature sensor 39 is provided. However, by providing the second temperature sensor 39 in each cap heater 34, more precise temperature control becomes possible, and the heating controllability is further improved. Can be improved.

  Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 15, the same components as those in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted.

  In the second embodiment, the cap heater 34 has a heating portion 66 having a double structure in which an outer circular portion 66a and an inner circular portion 66b are concentrically multiplexed. Further, the cap heater 34 has a hanging portion 53 (see FIG. 8) inserted through the first notch portion 54 bent along the upper surface of the heat insulating portion 31, and extends toward the center of the heat insulating portion 31. It has a protrusion 65.

  The outer circle portion 66a is fixed to the extension portion 65 on the base end side by welding or the like. Further, the outer circular portion 66a and the inner circular portion 66b are fixed by welding or the like at a position substantially opposed to the extending portion 65, that is, at the distal end side. Note that, on the distal end side, the outer circular portions 66a and the inner circular portions 66b are not connected to each other, and the distal ends of the heat generating portions 66 are separated. That is, the heat generating portion 66 has a double structure in which the outer circular portion 66a and the inner circular portion 66b are integrated by one turn. Although not shown, as in the first embodiment, a coil-shaped resistance heating element is sealed in the heating section 66 with the boundary between the extension section 65 and the outer circular section 66a as a heating point.

  In the second embodiment, the heat generating portion 66 is doubled. Therefore, the output of the cap heater 34 can be increased, and the bottom region below the processing chamber 6 (see FIG. 1) can be more effectively heated. In addition, since the cap heater 34 can be formed by one turn of the conducting wire 59 (see FIG. 11), only one power supply unit is required for the cap heater 34 having the double heating unit 66, and the control system can be simplified and Thus, the number of parts can be reduced.

  FIG. 16 shows a modification of the second embodiment of the present invention. In the modified example, the extension 65 in the second embodiment is a reinforcement 67 having the same shape as the V-shaped reinforcement 52 (see FIG. 7) of the first embodiment.

  By bending downward at the root of the reinforcing portion 67 to form a hanging portion (not shown), a direction along the peripheral surface of the heat insulating portion 31 of the cap heater 34 and a direction away from the heat insulating portion 31. Can be improved.

  Next, a third embodiment of the present invention will be described with reference to FIGS. The same components as those in FIG. 7 are denoted by the same reference numerals, and the description thereof is omitted.

  In the third embodiment, the hanging portion 53 is formed at the center of the heat generating portion 51 in a plan view. Further, it has an extending portion 65 that is bent in a horizontal direction above the hanging portion 53 and extends outward from the center of the heat insulating portion 31. The extension portions 65 are formed in a pair of I-shape so as to be connected to both ends of the heat generating portion 51, and are joined together at the upper end of the hanging portion 53. The second temperature sensor 39 is bent horizontally from the center of the heat generating portion 51 along the upper surface of the heat insulating portion 31 in a direction opposite to the extending portion 65, and is formed to be connected to the side surface of the heat generating portion 51. As shown in FIG. 19, the upper end of the hanging portion 53 has a larger diameter than that below the hanging portion 53 because the pair of extending portions 65 and the second temperature sensor 39 merge. The second temperature sensor 39 encloses a first temperature sensor 39B for detecting the temperature of the heat generating portion 51 and a second sensor 39B for detecting a temperature near the center of the bottom region.

  The heat generating portion 51 is formed in a substantially cardioid shape (heart shape). In other words, the heat generating portion 51 is formed in a shape in which cardioid cusps are separated. As in the first embodiment, a coil-shaped resistance heating element is sealed in the heating section 51 with the boundary between the extension section 65 and the heating section 51 as a heating point. Preferably, the curved portion of the cardioid shape is formed in a perfect circle. The hanging part 53 is installed so as to penetrate the hole 30, the seal cap 25 and the base 24.

  Since the resistance heating element is sealed up to the cardioid-shaped cusp, the heating portion in the annular region by the heating portion 51 can be increased, and the heating performance by the cap heater 34 can be improved. Thereby, the bottom region can be heated more effectively, and the in-plane temperature uniformity of the wafer 8 can be further improved. In addition, since the heat-generating portion 51 is supported by the hanging portion 53 provided at the center position of the heat-generating portion 51 in a plan view, the heat-generating portion 51 is unlikely to sag or deform due to aging. Since the cap heater 34 can be operated for a long time, productivity can be improved.

  In the first, second, and third embodiments, a coil-shaped resistance heating element is exemplified as the heating element. However, a lamp heater such as a halogen lamp may be used as the heating element. It goes without saying that it is good.

  The present invention can be suitably applied not only to the formation of the oxide film described above but also to the formation of a nitride film. For example, a nitride film can be formed by using the source gas exemplified above and an NH3 gas as a reaction gas.

  Further, a metal-based thin film containing a metal element such as titanium (Ti), zirconium (Zr), hafnium (Hf), tantalum (Ta), niobium (Nb), aluminum (Al), molybdenum (Mo), and tungsten (W). The present invention can be suitably applied to the case of forming.

(Preferred embodiment of the present invention)
Hereinafter, preferred embodiments of the present invention will be additionally described.

(Appendix 1)
According to one aspect of the present invention,
A substrate holder for holding a plurality of substrates,
A heat insulating portion provided below the substrate holder,
A reaction tube having therein a processing chamber for processing the substrate,
A first heating unit provided around the reaction tube;
A second heating unit provided between the substrate holder and the heat insulating unit,
The second heating unit includes:
A substantially annular heating section;
A hanging portion extending downward from the heat generating portion,
There is provided a substrate processing apparatus configured such that the heat generating portion is accommodated in an annular region having a smaller diameter than the substrate.

(Appendix 2)
An apparatus according to claim 1, wherein:
The annular region is at least 1/5 and at most 3/5 of the diameter of the substrate.

(Appendix 3)
An apparatus according to claim 1 or 2, wherein
A temperature measuring member is connected to a surface of the heat generating portion.

(Appendix 4)
The apparatus according to any one of supplementary notes 1 to 3, wherein
The first heating unit includes:
An upper heater for heating an upper region in which the substrate holder is accommodated in the processing chamber;
A lower heater that heats a lower region in which the heat insulating unit in the processing chamber is stored,
The heat generating portion is installed at a height at least equal to or higher than the height of a boundary between the upper heater and the lower heater.

(Appendix 5)
The apparatus according to claim 4, wherein:
The temperature of the heat generating portion is equal to or lower than the temperature of the lower heater.

(Appendix 6)
An apparatus according to any of claims 1 to 3, wherein
The heat generating portion is formed in an arc shape (a horseshoe shape).

(Appendix 7)
The apparatus according to claim 4, wherein:
The second heating section has a V-shaped reinforcing section protruding from the heating section toward the outer periphery.

(Appendix 8)
An apparatus according to claim 3, wherein:
A temperature measuring member supporting portion is provided on the heat generating portion, and the temperature detector is supported by the temperature measuring member supporting portion in a state of being in contact with an upper surface of the heat generating portion.

(Appendix 9)
The apparatus according to claim 8, wherein:
The temperature measuring member supporting portion is provided at a position where a center line of the temperature detector is tangent or substantially tangent to an imaginary circle formed by a center line of the heat generating portion.

(Appendix 10)
An apparatus according to claim 7, wherein:
A root portion of the reinforcing portion is connected to the hanging portion, and an insulating member is attached to only one of the pair of heating elements in the hanging portion.

(Appendix 11)
The apparatus according to claim 8, wherein:
A spacer is provided below the heat generating portion on the upper surface of the heat insulating portion, and a gap is formed between the spacer and the heat generating portion.

(Appendix 12)
An apparatus according to claim 11, wherein
The reinforcing section is provided above an exhaust section of the processing chamber.

(Appendix 13)
An apparatus according to claim 1 or 2, wherein
A plurality of the second heating units are provided concentrically.

(Appendix 14)
An apparatus according to claim 1 or 2, wherein
The heat generating portion has an outer circular portion and an inner circular portion provided in a concentric multiple circle shape, and the outer circular portion is connected to the reinforcing portion on a base end side, and the outer circular portion and the inner circular portion Are connected on the distal end side.

(Appendix 15)
An apparatus according to any of claims 1 to 14, wherein
A cutout portion is formed on the entire peripheral surface of the heat insulating portion in the vertical direction, and the hanging portion is inserted through the cutout portion.

(Appendix 16)
An apparatus according to claim 1 or 2, wherein
The heat generating portion is formed in a cardioid shape (heart shape).

(Appendix 17)
The apparatus according to claim 16, wherein:
The hanging portion is formed at a center position of the heat generating portion in a plan view.

(Appendix 18)
An apparatus according to claim 2, wherein:
The annular region is at least 1/5 and at most 3/5 of the diameter of the substrate.

(Appendix 19)
The apparatus according to claim 18, wherein:
The annular region is at least 3/10 and at most 8/15 of the diameter of the substrate.

(Appendix 20)
An apparatus according to any of claims 1 to 19, wherein
The diameter of the heat generating portion is a size that can be heated at a position where the in-plane temperature distribution of the lowermost substrate becomes uniform.

(Appendix 21)
According to another aspect of the present invention,
A step of loading a substrate holder, which is installed above the heat insulating unit and holds a plurality of substrates, into the processing chamber;
A first heating section provided around the processing chamber and a substantially annular second heating section provided between the substrate holder and the heat insulating section, for heating the processing chamber;
Supplying a processing gas into the processing chamber,
In the step of heating the processing chamber, the substrate processing method in which the heating unit of the second heating unit formed so as to fit in an annular region smaller in diameter than the substrate heats a bottom region in the processing chamber, or a semiconductor. A method for manufacturing a device is provided.

(Appendix 22)
According to yet another aspect of the present invention,
A procedure of loading a substrate holder that is installed above the heat insulating unit and holds a plurality of substrates into the processing chamber;
A first heating unit provided around the processing chamber and a substantially annular second heating unit provided between the substrate holder and the heat insulating unit for heating the processing chamber;
Supplying a processing gas into the processing chamber,
In the step of heating the processing chamber, a program that causes a computer to execute such that the heating unit of the second heating unit formed so as to fit in an annular region smaller in diameter than the substrate heats a bottom region in the processing chamber. Alternatively, a computer-readable recording medium on which the program is recorded is provided.

(Appendix 23)
According to yet another aspect of the present invention,
A heating unit installed between a substrate holder holding a plurality of substrates and a heat insulating unit installed below the substrate holder,
The heating unit is
A substantially annular heating section;
A hanging portion extending downward from the heat generating portion,
A heating section is provided, wherein the heating section is configured such that the heating section fits in an annular region having a smaller diameter than the substrate.

(Appendix 24)
According to yet another aspect of the present invention,
A substrate holder for holding the substrate, a heat insulating portion provided below the substrate holder, a reaction tube defining a processing chamber for processing the substrate, and a second tube provided so as to surround the periphery of the reaction tube. 1 heating part, and a second heating part provided between the substrate holder and the heat insulating part, wherein the second heating part is an annular shape having a smaller diameter than the substrate, A substrate processing apparatus configured to heat a portion in a radial direction is provided.

(Appendix 25)
According to yet another aspect of the present invention,
Loading a substrate holder for holding a substrate into the processing chamber, heating the processing chamber with a first heating unit and a second heating unit, and supplying and exhausting a processing gas into the processing chamber; Loading and unloading the substrate holder from the processing chamber, wherein in the step of heating the processing chamber, the second heating unit is arranged radially on the center side of the periphery of the substrate from below the substrate holder. And a method for manufacturing a semiconductor device.

2 Side Heater 6 Processing Room 7 Boat 31 Heat Insulating Section 34 Cap Heater 38 Temperature Control Section 51, 66 Heating Section 53 Hanging Part 61 Resistance Heating Element

Claims (12)

A substrate holder for holding a plurality of substrates,
A heat insulating portion provided below the substrate holder,
A processing chamber for storing the substrate holder and processing the substrate,
A first heating unit installed around the processing chamber and configured to heat the processing chamber from a side;
A second heating unit provided in the processing chamber,
The second heating unit includes:
An annular portion provided between the substrate holder and the heat insulating portion and provided with a one-turn ring-shaped heating element;
A hanging portion extending downward from the annular portion,
A substrate processing apparatus configured such that the heating element is accommodated in an annular area smaller in diameter than the substrate.   2. The substrate processing apparatus according to claim 1, wherein the annular area is at least 1/5 and at most 3/5 of the diameter of the substrate. 3. The second heating portion has the heating element protective tube is enclosed structure,
The heating element is a coil-shaped resistance heating element that is formed in the ring shape with a part open, the center line of which forms a circle,
The substrate processing apparatus according to claim 1, wherein the hanging portion connects to both ends of the protection tube of the annular portion. The first heating unit includes:
An upper heater for heating an upper region in which the substrate holder is accommodated in the processing chamber;
A lower heater that heats a lower region in which the heat insulating unit in the processing chamber is stored,
2. The substrate according to claim 1, wherein the heat generating portion, which is the portion of the annular portion provided with the heat generating element, is installed at a height at least equal to a height of a boundary between the upper heater and the lower heater. 3. Processing equipment.   The substrate processing apparatus according to claim 4, wherein a temperature measuring member is connected to a surface of the heating unit, and a temperature of the heating unit is set to be equal to or lower than a temperature of the lower heater. A temperature measuring member supporting portion is provided on the heat generating portion, and a temperature detector is supported by the temperature measuring member supporting portion in contact with an upper surface of the heat generating portion,
6. The method of manufacturing a semiconductor device according to claim 5, wherein a spacer is provided below the heat generating portion on the upper surface of the heat insulating portion, and a gap is formed between the spacer and the heat generating portion. The annular portion has the reinforcing portion of the V-shaped projecting toward the outer peripheral side from both ends of the heat generating portion is a portion where the heating element is provided within said annular portion, said reinforcing portion includes the heating unit 3. The substrate processing apparatus according to claim 2, wherein a force applied to a boundary between the reinforcing member and the reinforcing portion reduces moments in both a tangential direction and a radial direction. The second heating portion is bent in a horizontal direction above the hanging portion, extends outward from the center of the heat insulating portion, and is a portion of the annular portion where the heating element is provided. The substrate processing apparatus according to claim 2, further comprising a pair of extending portions formed in an I shape so as to be connected to both ends of the portion. 8. The substrate processing apparatus according to claim 7, wherein a cutout portion is formed in the heat insulating portion over the entire length in the vertical direction, and the hanging portion is inserted through the cutout portion.   The substrate processing apparatus according to claim 8, wherein the hanging portion is formed at a center position of the heat generating portion in a plan view. A step of loading a substrate holder, which is installed above the heat insulating unit and holds a plurality of substrates, into the processing chamber;
A first heating unit provided around the processing chamber and a second heating unit provided in the processing chamber, for heating the processing chamber;
Supplying a processing gas into the processing chamber,
In the step of heating the inside of the processing chamber, the second heating unit is provided between the substrate holder and the heat insulating unit, and includes an annular portion in which a ring-shaped heating element is enclosed, and an annular portion. A method of manufacturing a semiconductor device, comprising: a heating element formed so as to fit in an annular area having a diameter smaller than that of the substrate, the heating element having a hanging part extending downward and heating the bottom area in the processing chamber. A heating unit installed between the substrate holder and the heat insulating unit in the substrate processing apparatus to be depressurized,
The heating unit is
An annular portion in which a ring-shaped heating element is enclosed in a protective tube;
A hanging portion connected to both ends of the protection tube of the annular portion and extending downward from the annular portion,
A heating unit configured such that a heating unit, which is a portion in which the heating element is sealed, of the annular unit is accommodated in an annular region having a smaller diameter than the substrate.