JP2012009702A - Heating device and manufacturing method of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce contact between a heating element and a heat insulator at the time of thermal expansion of the heating element and reduce damage of components constituting a heating device.SOLUTION: A heating device comprises an annularly formed heating element, a heat insulator placed around the circumference of the heating element, and a fixing part which fixes the heating element onto an inner wall of the heat insulator. At least when the heating element is at a room temperature, the distance between the heating element and the inner wall of the heat insulator is set to be larger as it moves away from the fixing part.

Description

  The present invention relates to a heating device and a method for manufacturing a semiconductor device.

  As one step of a method of manufacturing a semiconductor device such as a DRAM, a substrate processing step of heating and processing a substrate such as a silicon wafer may be performed. Such a process is performed by a substrate processing apparatus including a processing chamber that accommodates and processes a substrate, and a heating device that heats the processing chamber. The heating device includes an annular heating element that surrounds the outer periphery of the processing chamber, a heat insulator that is provided so as to surround the outer periphery of the heating element, and a holding member that fixes the heating element to the inner wall of the heat insulator (for example, Patent Document 1).

JP-A-4-318923

  However, in the above-described heating device, when the heating element thermally expands as the temperature rises, the heating element and the heat insulator come into contact with each other, and these members may be damaged. In particular, since the amount of displacement of the heating element increases cumulatively with distance from the holding member, contact between the heating element and the heat insulator tends to occur at a location away from the holding member.

  Therefore, the present invention provides a heating that can suppress the contact between the heating element and the heat insulator when the heating element is thermally expanded, or the interference between the heating element and the pin member, and reduce the damage to the components of the heating device. An object is to provide a device and a method for manufacturing a semiconductor device.

  According to an aspect of the present invention, an annular heating element, a heat insulator provided so as to surround an outer periphery of the heat generator, and a fixing portion that fixes the heat generator to an inner wall of the heat insulator. A heating device provided, wherein at least when the heating element is at room temperature, a distance between the heating element and the inner wall of the heat insulator is set so as to increase as the distance from the fixing portion increases. Is provided.

  According to another aspect of the present invention, an annularly formed heating element, a heat insulating body provided so as to surround an outer periphery of the heating element, a fixing portion that fixes the heating element to an inner wall of the heat insulating body, And a step of carrying a substrate into a processing chamber provided inside the heating element of the heating device, and a step of heating the substrate in the processing chamber by heating the heating element to process the substrate. There is provided a method for manufacturing a semiconductor device, wherein at least when the heating element is at room temperature, a distance between the heating element and an inner wall of the heat insulator is set to increase as the distance from the fixing portion increases.

  According to the heating device and the method for manufacturing a semiconductor device according to the present invention, it is possible to suppress contact between the heating element and the heat insulator when the heating element thermally expands, and to reduce damage to the components of the heating device. Become.

1 is a vertical sectional view of a substrate processing apparatus according to a first embodiment of the present invention. It is a perspective view of the heater unit which concerns on the 1st Embodiment of this invention. It is the elements on larger scale of the heater unit which concerns on the 1st Embodiment of this invention. (A) is the schematic which illustrates the linear material which can comprise the heat generating body which concerns on the 1st Embodiment of this invention, (b) is the schematic which illustrates the plate-shaped material which can comprise this heat generating body It is. (A) is the elements on larger scale of the electric power feeding part periphery which concerns on the 1st Embodiment of this invention, (b) is a side view of an enlarged part. It is a horizontal sectional view of the heater unit before temperature rising concerning the 1st embodiment of the present invention. It is a horizontal sectional view of the heater unit after temperature rising concerning the 1st embodiment of the present invention. It is the schematic which shows the expansion direction of the heat generating body which concerns on the 1st Embodiment of this invention. It is the schematic which illustrates the measurement result regarding the thermal expansion of the heat generating body which concerns on the 1st Embodiment of this invention. (A) is the elements on larger scale around the dummy terminal which concerns on the 2nd Embodiment of this invention, (b) is a side view of an enlarged part. (A) is the elements on larger scale around a pin member as a modification of the fixed part concerning the present invention, and (b) is a side view of an enlarged part. It is a horizontal sectional view of the heater unit before temperature rising concerning the 2nd Embodiment of the present invention. It is a horizontal sectional view of the heater unit after temperature rising concerning the 2nd Embodiment of the present invention. It is the schematic which shows the expansion direction of the heat generating body which concerns on the 2nd Embodiment of this invention. It is the schematic which illustrates the measurement result regarding the thermal expansion of the heat generating body which concerns on the 2nd Embodiment of this invention. It is the schematic which shows the mode of the heat deformation of a heat generating body at the time of making a heat generating body and a heat insulator into concentric form in a room temperature state, (a) is a state before temperature rising, (b) is temperature rising. Each of the following is shown. It is the elements on larger scale which show the mode of heat deformation of a heat generating body, (a) is a state before temperature rising, (b) is a state after temperature rising, (c) is shearing of a holding member and heat_generation | fever by heat deformation. (D) shows a state in which the holding member is pulled out due to thermal deformation.

<First Embodiment>
A first embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a vertical sectional view of a substrate processing apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view of the heater unit according to the first embodiment of the present invention. FIG. 3 is a partially enlarged view of the heater unit according to the first embodiment of the present invention. FIG. 4A is a schematic view illustrating a linear material constituting the heating element according to the first embodiment of the present invention, and FIG. 4B illustrates a plate-like material constituting the heating element. FIG. Fig.5 (a) is the elements on larger scale around the electric power feeding part which concerns on the 1st Embodiment of this invention, FIG.5 (b) is a side view of an enlarged part.

(1) Configuration of substrate processing apparatus

  The configuration of the substrate processing apparatus according to one embodiment of the present invention will be described below. The substrate processing apparatus according to the present embodiment is configured as a batch type vertical hot wall type low pressure CVD (Chemical Vapor Deposition) apparatus as illustrated in FIG.

The substrate processing apparatus according to this embodiment includes a vertical process tube 11 that is vertically supported. The process tube 11 includes an outer tube 12 and an inner tube 13. The outer tube 12 and the inner tube 13 are each integrally formed of a material having high heat resistance such as quartz (SiO ₂ ) and silicon carbide (SiC). The outer tube 12 is formed in a cylindrical shape with the upper end closed and the lower end opened. The inner tube 13 is formed in a cylindrical shape with both upper and lower ends opened. The inner diameter of the outer tube 12 is configured to be larger than the outer diameter of the inner tube 13. The outer tube 12 is provided concentrically with the inner tube 13 so as to surround the outer side of the inner tube 13. In the inner tube 13, a processing chamber 14 is formed for storing and processing the wafers 1 stacked in multiple stages in a horizontal posture by a boat 22 as a substrate holder. The lower end opening of the inner tube 13 constitutes a furnace port 15 for taking in and out the boat 22.

  Lower ends between the outer tube 12 and the inner tube 13 are hermetically sealed by a manifold 16 formed in a circular ring shape. The manifold 16 is made of, for example, stainless steel (SUS). The manifold 16 is detachably attached to the inner tube 13 and the outer tube 12 for replacement of the inner tube 13 and the outer tube 12, respectively. Since the manifold 16 is supported in a horizontal posture by the heater base 19, the process tube 11 is installed vertically.

  An upstream end of the exhaust pipe 17 is connected to the side wall of the manifold 16. The inside of the exhaust pipe 17 communicates with an exhaust path 18 formed as a cylindrical hollow body (gap) between the inner tube 13 and the outer tube 12. The cross-sectional shape of the exhaust path 18 is, for example, a circular ring shape with a constant width. The exhaust pipe 17 is in a state of being connected to the lowermost end portion of the exhaust path 18 which is a cylindrical hollow body. The exhaust pipe 17 is provided with a pressure sensor 17a, an APC (Auto Pressure Controller) valve 17b as a pressure adjusting valve, and a vacuum exhaust device 17c in order from the upstream. By controlling the opening degree of the APC valve based on the pressure detected by the pressure sensor while operating the vacuum exhaust device, the pressure in the processing chamber 14 can be set to a predetermined pressure (degree of vacuum). It is configured. An exhaust line for exhausting the atmosphere in the processing chamber 14 is mainly configured by the exhaust pipe 17, the pressure sensor 17a, the APC valve 17b, and the vacuum exhaust device 17c. The pressure sensor 17a, the APC valve 17b, and the vacuum exhaust device 17c are connected to a controller 280 as a control unit. The controller 280 is configured to control the valve opening degree of the APC valve 17b based on the pressure information detected by the pressure sensor 17a so that the pressure in the processing chamber 14 can be set to a predetermined processing pressure. Has been.

  A disk-shaped seal cap 20 that closes the lower end opening of the manifold 16 is brought into contact with the manifold 16 from the lower side in the vertical direction. The outer diameter of the seal cap 20 is substantially equal to the outer diameter of the outer tube 12 and the manifold 16. The seal cap 20 is configured to be raised and lowered in the vertical direction by a boat elevator 21 (only a part of which is shown) provided outside the process tube 11. A rotation mechanism 25 is provided below the seal cap 20. The rotating shaft of the rotating mechanism 25 passes through the seal cap 20 vertically. On the rotating shaft of the rotating mechanism 25, the above-described boat 22 is vertically supported and supported. As described above, the boat 22 is configured to hold a plurality of wafers 1 stacked in multiple stages in a horizontal posture with the centers aligned. The boat 22 can be rotated in the processing chamber 14 by operating the rotating mechanism 25.

A gas introduction pipe 23 is connected to the seal cap 20 in the vertical direction. A source gas supply device 23 a and a carrier gas supply device 23 b are connected to the upstream side end (lower end) of the gas introduction pipe 23. The downstream end (upper end) of the gas introduction pipe 23 is configured to supply (spout) gas into the processing chamber 14. The gas supplied from the gas introduction pipe 23 into the processing chamber 14 (inner tube 13) flows through the surface of each wafer 1 held in the processing chamber 14, and then is exhausted from the upper end opening of the inner tube 13. It flows out into the exhaust pipe 17 and is exhausted from the exhaust pipe 17. A gas supply line for supplying gas into the processing chamber 14 is mainly configured by the gas introduction pipe 23, the raw material gas supply device 23a, and the carrier gas supply device 23b. The source gas supply device 23a and the carrier gas supply device 23b are connected to a controller 280 as a control unit. The controller 280 is configured to control the source gas supply device 23a and the carrier gas supply device 23b so as to supply the source gas and the carrier gas at a predetermined flow rate into the processing chamber 14 at a predetermined timing. ing.

  A temperature sensor 24 is disposed in the vertical direction in the gap between the outer tube 12 and the inner tube 13. The temperature sensor 24 is connected to the controller 280. Based on the temperature information detected by the temperature sensor 24, the controller 280 controls the energization state (power supply by the pair of power supply units 45 and 46) to each heating element 42 included in the heater unit 30 described later. The surface temperature of the wafer 1 held in the processing chamber 14 is configured to be a predetermined processing temperature.

(2) Configuration of Heater Unit A heater unit 30 as a heating device for heating the inside of the process tube 11 is provided outside the outer tube 12 so as to surround the outer tube 12. The heater unit 30 includes an annular heating element 42, a heat insulating body 33 provided so as to surround the outer periphery of the heating element 42, and a pair of power supply units 45 as fixed parts connected to both ends of the heating element 42. , 46 and a case 31 surrounding the outside of the heat insulator 33.

At least one heating element 42 is provided in the vertical direction so as to surround the outer tube 12. As shown in FIGS. 2 and 3, the heating element 42 is configured in an annular shape so as to surround the outer periphery of the outer tube 12. Both end portions of the heating element 42 are fixed in close proximity without being in contact with each other, and are in an electrically non-contact state. In other words, the heating element 42 is not electrically completely circular but is configured in a C-shaped ring shape, for example. As a material constituting the heating element 42, for example, a resistance heating material such as Fe—Cr—Al alloy, MoSi ₂ , SiC or the like can be used, and the shape thereof is a linear shape as shown in FIG. A material may be sufficient and a plate-shaped material as shown in (b) may be sufficient. 2, 3, and 5, a plurality of ridges (projections) 42 a and valleys (notches) 42 b are alternately connected to the upper and lower ends of the heating element 42. . That is, the heating element 42 is formed in a meandering shape (wave shape).

  The ends of the pair of power feeding portions 45 and 46 are connected to both ends of the heating element 42 described above. The pair of power feeding portions 45 and 46 are fixed to the heat insulating body 33 through a heat insulating body 33 (side wall portion 35) described later. That is, the pair of power feeding units 45 and 46 functions as a fixing unit that fixes the heat generating body 42 to the inner wall of the heat insulating body 33. FIG. 5A shows a partially enlarged view (plan view) around the power feeding portions 45 and 46 viewed from the center side of the heating element 42 (viewed from the process tube 11 side). As described above, the heating element 42 is fixed only at one place (an end portion of the heating element 42) by a pair of power feeding parts 45 and 46 as fixing parts. That is, the fixing using a holding body such as a pin is not performed except for the pair of power feeding units 45 and 46.

  A pair of electric power feeding parts 45 and 46 is comprised by electroconductive materials, such as a metal. By passing a current from one end of the heat generating element 42 to the other end via the pair of power supply units 45 and 46, the heat generating element 42 is heated and the inside of the process tube 11 is heated. Power supply to the heating element 42 via the pair of power supply units 45 and 46 is controlled by the controller 280.

The heat insulator 33 is provided so as to surround the outer periphery of the heating element 42. The heat insulator 33 includes a cylindrical side wall portion 35 whose upper and lower ends are open, and a ceiling wall portion 34 that covers an upper opening of the side wall portion 35, and is formed in a cylindrical shape with its lower end opened. The heat insulator 33 is provided concentrically with respect to the outer tube 12. The side wall portion 35 and the ceiling wall portion 34 are formed of a heat insulating material such as fibrous or spherical alumina (Al ₂ O ₃ ) or silica (SiO ₂ ), for example. The side wall portion 35 and the ceiling wall portion 34 are integrally formed by, for example, a vacuum foam method or the like. The side wall portion 35 is not limited to being integrally molded, and may be configured by stacking a plurality of circular heat insulating materials. By comprising in this way, it becomes possible to suppress the damage of the side wall part 35 when stress is added to the side wall part 35, or to improve maintainability.

  The case 31 is provided so as to surround the outer periphery of the heat insulator 33. The case 31 is formed in, for example, a cylindrical shape with the upper end closed and the lower end opened. The case 31 is made of, for example, stainless steel (SUS). A gap 32 between the outer peripheral surface of the heat insulator 33 and the inner peripheral surface of the case 31 functions as a space for air cooling. In addition, you may comprise so that the exhaust port which penetrates the ceiling wall part 34 and the ceiling wall of case 31 may be provided, and the atmosphere between the heat insulating body 33 and the outer tube 12 may be forced-air-cooled.

  When the heating element 42 is heated, it has a characteristic of extending in the circumferential direction and the radial direction due to thermal expansion. As a result, the heating element 42 and the inner wall of the heat insulating body 33 may contact and interfere with each other. In particular, when the heating element 42 is formed in a meandering manner as in the present embodiment, the amount of elongation increases and contact is likely to occur. When the heating element 42 and the inner wall of the heat insulating body 33 come into contact with each other and interfere with each other, a local temperature increase (abnormal temperature increase) of the heating element 42 may occur, and the heating element 42 may melt. Further, stress is applied to the heat generating body 42 and the heat insulating body 33, and there is a possibility that these members may be damaged. Further, if the distance between the heating element 42 and the inner wall of the heat insulating body 33 becomes non-uniform along the circumferential direction of the heating element 42 due to the extension of the heating element 42 in the radial direction, the temperature distribution of the heating element 42 becomes uniform. There is a case where the quality of the substrate processing deteriorates due to a decrease in the circumferential direction. That is, the temperature of the heating element 42 rises abnormally at a location where the distance between the heating element 42 and the inner wall of the heat insulating body 33 is short, or the temperature of the heating element 42 at a location where the distance between the heating element 42 and the inner wall of the heat insulating body 33 is far. May decrease.

  Therefore, in the present embodiment, at least when the heating element 42 is at room temperature, the distance between the heating element 42 and the inner wall of the heat insulating body 33 is increased as the distance from the power feeding parts 45 and 46 as the fixing parts increases. Thus, the above-mentioned problems are solved. FIG. 6 is a horizontal sectional view of the heater unit 30 (in a room temperature state) before the temperature increase according to the present embodiment. As shown in FIG. 6, when at least the heating element 42 is at room temperature, the distance between the heating element 42 and the inner wall of the heat insulating body 33 gradually increases as the distance from the pair of power feeding portions 45 and 46 increases. Then, A <B <C.

  In this state, when the heating element 42 is heated to a temperature at the time of substrate processing, for example, each part of the heating element 42 expands in the direction shown in FIG. 8 due to thermal expansion. FIG. 8 shows the displacement direction and displacement amount of each part of the heating element 42 by the direction and length of the arrow, respectively. Since the heating element 42 is fixed at one place by the pair of power feeding portions 45 and 46, each part of the heating element 42 starts from the area near the pair of power feeding sections 45 and 46 (area indicated by reference numeral A <b> 1). Displacement so that it swells (so as to move away from the pair of power supply portions 45 and 46). Note that the amount of displacement of the heating element 42 increases as the distance from the pair of power supply units 45 and 46 increases.

As a result, at least when the heating element 42 is in the temperature state during substrate processing, the distance between the heating element 42 and the inner wall of the heat insulating body 33 is equal in the circumferential direction of the heating element 42. FIG. 7 is a horizontal cross-sectional view of the heater unit 30 after the temperature rise (in the temperature state during substrate processing) according to the present embodiment.
As shown in FIG. 7, at least when the heating element 42 is in a temperature state during substrate processing, the distance between the heating element 42 and the inner wall of the heat insulating body 33 becomes equal over the circumferential direction of the heating element 42 due to thermal expansion. In the figure, A≈B≈C.

(3) Substrate Processing Step Next, a film forming step as an example of a substrate processing (heat treatment) step performed by the above-described substrate processing apparatus will be briefly described. In the following description, the operation of each part of the substrate processing apparatus is controlled by the controller 280.

  As shown in FIG. 1, a boat 22 loaded with a plurality of wafers 1 (wafer charging) is lifted by a boat elevator 21 and loaded into a processing chamber 14 (boat loading). In this state, the seal cap 20 is in a state where the lower end opening of the manifold 16 is sealed.

  The process tube 11 is evacuated through the exhaust pipe 17 so that the inside of the process tube 11 has a predetermined pressure (degree of vacuum). Further, the process tube 11 is heated by the heater unit 30 so that the inside of the process tube 11 becomes a predetermined temperature. That is, by passing an electric current from one end of the heating element 42 to the other end via the pair of power supply units 45 and 46, the meandering heating element 42 is heated to raise the temperature in the process tube 11. At this time, feedback control of the state of energization to the heating element 42 of the heater unit 30 is performed based on the temperature information detected by the temperature sensor 24 so that the inside of the processing chamber 14 has a predetermined temperature distribution. Subsequently, the rotation mechanism 25 is operated to start the rotation of the wafer 1.

  Next, the raw material gas controlled to a predetermined flow rate is introduced into the processing chamber 14 through the gas introduction pipe 23. The introduced source gas flows through the processing chamber 14, then flows out from the upper end opening of the inner tube 13 into the exhaust path 18 and is exhausted from the exhaust pipe 17. The raw material gas contacts the surface of the wafer 1 as it passes through the processing chamber 14. At this time, the wafer 1 is processed, and a desired thin film is deposited (deposition) on the surface of the wafer 1 by, for example, a thermal CVD reaction. Is done.

  When a preset processing time has elapsed, an inert gas is supplied from an inert gas supply source (not shown), the inside of the processing chamber 14 is replaced with an inert gas, and the pressure in the processing chamber 14 is set to normal pressure. Return to. Further, the operation of the rotation mechanism 25 is stopped.

  Thereafter, the seal cap 20 is lowered by the boat elevator 21 to open the lower end of the manifold 16, and the boat 22 holding the processed wafer 1 is unloaded from the lower end of the manifold 16 to the outside of the process tube 11 (boat unloading). Loading). Thereafter, the processed wafer 1 is taken out from the boat 22 (wafer discharge).

(4) Effects according to the present embodiment According to the present embodiment, one or more of the following effects (a) to (e) are achieved.

(A) According to the present embodiment, at least when the heating element 42 is at room temperature, the distance between the heating element 42 and the inner wall of the heat insulating body 33 increases as the distance from the power feeding parts 45 and 46 as the fixing parts increases. I am doing so. As a result, when the heating element 42 is in the temperature state during substrate processing, the distance between the heating element 42 and the inner wall of the heat insulating body 33 becomes equal over the circumferential direction of the heating element 42 due to thermal expansion. Thereby, unnecessary contact and interference between the heating element 42 and the inner wall of the heat insulating body 33 can be prevented. And the damage of the structural member of the heater unit 30 can be suppressed. For example, the local temperature rise (abnormal temperature rise) of the heating element 42 can be prevented and the fusing of the heating element 42 can be avoided. For example, since the heat generating body 42 and the inner wall of the heat insulating body 33 are not in contact with each other, the stress applied to these members can be reduced.

(B) According to the present embodiment, when at least the heating element 42 is in the temperature state during substrate processing, the distance between the heating element 42 and the inner wall of the heat insulating body 33 extends over the circumferential direction of the heating element 42 due to thermal expansion. It becomes equivalent. As a result, the wafer 1 can be heated uniformly over the circumferential direction of the heating element 42. As a result, the in-plane uniformity of substrate processing can be improved.

(C) According to the present embodiment, the heating element 42 is fixed only at one place (end portion) by the pair of power feeding portions 45 and 46 as fixing portions. That is, the fixing using a holding body such as a pin is not performed except for the pair of power feeding units 45 and 46. As a result, the heating element 42 can be prevented from being damaged or short-circuited due to thermal expansion. In other words, the heating element 42 according to the present embodiment is not restrained at a part other than the connection part with the power feeding units 45 and 46 and thermal expansion is not hindered, so that the stress applied to the heating element 42 and the holding member is reduced. As a result, deformation, damage, short circuit, etc. of the heating element 42 can be suppressed.

  For reference, the state of thermal deformation of the heating element 42 ′ when the heating element 42 ′ and the inner wall of the heat insulating body 33 ′ are concentric in a room temperature state will be described with reference to FIG. 16.

  FIG. 16A shows the state before the heating element 42 ′ is heated, and FIG. 16B shows the state after the heating element 42 ′ is heated. According to FIG. 16A, before the temperature rise, the distance between the heating element 42 'and the inner wall of the heat insulating body 33' is uniform over the entire circumference of the heating element 42 '. However, as shown in FIG. 16 (b), when the heating element 42 'is heated to, for example, the temperature during substrate processing, the heating element 42' expands in the radial direction, and the heating element 42 'and the heat insulating element 33' The distance between the inner wall and the inner wall is not uniform over the circumferential direction of the heating element 42 '(A> B> C in the figure). That is, since the pair of power feeding portions 45 ′ and 46 ′ are fixed to the heat insulating body 33 ′, each part of the heat generating body 42 ′ expands from the region near the pair of power feeding portions 45 ′ and 46 ′. The distance between the heating element 42 ′ and the inner wall of the heat insulating body 33 ′ gradually decreases as the distance from the pair of power feeding portions 45 ′ and 46 ′ increases, and the region farthest from the pair of power feeding portions 45 ′ and 46 ′. Thus, the heat generating body 42 ′ and the heat insulating body 33 ′ may come into contact with each other. As a result, a local temperature rise (abnormal temperature rise) of the heating element 42 ′ may occur, and the heating element 42 ′ may be melted. In addition, the stress applied to the heating element 42 ′ or the like increases, and these members may be damaged. In addition, the uniformity of the temperature distribution of the heating element 42 'may be reduced.

  For reference, the state of the heating element 42 ′ fixed to the inner wall of each heat insulator by a plurality of holding bodies 41 ′ and in which the displacement of each part due to thermal expansion is restricted will be described with reference to FIG. 17.

FIG. 17A shows a state before the heating element 42 'is heated. On the upper and lower ends of the heating element 42 ′, a plurality of ridges 42 a ′ and valleys 42 b ′ are alternately arranged, and the heating element 42 ′ is formed in a meandering shape (wave shape). The heating element 42 ′ is held on the inner peripheral side of the heat insulating body by fixing each valley 42 b ′ to the inner peripheral side wall of the heat insulating body (not shown) by the holding body 41 ′. The holding body 41 ′ is directly disposed in the valley portion 42b ′. FIG. 17B shows a state after the temperature of the heating element 42 ′ is increased. As described above, the serpentine heating element 42 'extends in the circumferential direction due to thermal expansion. FIG. 17B shows a state in which the amount of expansion in the circumferential direction of the heating element 42 ′ exceeds a certain amount, and there is no movement allowance along the circumferential direction of the heating element 42 ′ (the holding body 41 ′ and the heating element 42 ′. Is showing interference). When the heating element 42 'further extends, the state shown in FIG. FIG. 17C shows a state in which the holding body 41 ′ is sheared, the heating element 42 ′ is cracked, and the heating element 42 ′ is short-circuited due to thermal deformation. As described above, when the amount of elongation in the circumferential direction exceeds a certain amount, the holding body 41 ′ interferes with the heating element 42 ′, plastic stress is applied to the heating element 42 ′, and the heating element 42 ′ is deformed. . In the area indicated by reference numeral A6, the state where the holding body 41 ′ is sandwiched and sheared by the valley portions 42b ′ from both sides is shown, and in the area indicated by reference numeral A4, the state in which the heating element 42 ′ is cracked is indicated by reference numerals. A region indicated by A5 shows a state in which a short circuit has occurred in the heating element 42 '. FIG. 17D is a side view of the heating element 42 ′ shown in FIG. 17C, and shows how the holding body 41 ′ is detached due to thermal deformation. A region indicated by reference numeral A6 shows a state in which the holding body 41 ′ is lifted from the heat insulating body due to deformation of the heat generating body 42 ′ and is about to be pulled out.

<Second Embodiment>
Below, the 2nd Embodiment of this invention is described, referring drawings.

  In this embodiment, a plurality of fixing portions are provided instead of one. That is, the heating element 42 is fixed at a plurality of locations (two locations in the present embodiment) using a pair of power feeding portions 45 and 46 as fixed portions and dummy terminals 45d and 46d as other fixed portions. Yes. Note that the pair of power feeding portions 45 and 46 and the pair of dummy terminals 45d and 46d are arranged so as to divide the heating element 42 into two substantially in the circumferential direction.

  FIG. 10A is a partially enlarged view around the dummy terminals 45d and 46d as fixing portions according to the present embodiment, and FIG. 10B is a side view of the enlarged portion. The pair of dummy terminals 45d and 46d are connected to one end of the heating element 42 (on the opposite side to the connecting portion with the power feeding parts 45 and 46) and penetrate the heat insulating body 33 (side wall 35) to form the heat insulating body 33. It is fixed to. That is, the pair of dummy terminals 45 d and 46 d function as a fixing portion that fixes the heating element 42 to the inner wall of the heat insulating body 33, similarly to the pair of power feeding portions 45 and 46. The dummy terminals 45d and 46d are made of a conductive material such as a metal, like the power feeding units 45 and 46. A current is passed from one end of the heating element 42 to the other end via the pair of dummy terminals 45d and 46d, whereby the heating element 42 is heated and the inside of the process tube 11 is heated. . Note that the power supply to the heating element 42 via the pair of power supply units 45 and 46 is controlled by the controller 280. The dummy terminals 45d and 46d may be configured not to be supplied with power. In this case, the dummy terminals 45d and 46d are not necessarily made of a conductive material, and may be made of a heat-resistant insulating material.

  Further, in the present embodiment, when at least the heating element 42 is in the room temperature state, the distance between the heating element 42 and the inner wall of the heat insulating body 33 is maximized at the central position between the adjacent fixed portions, and from this central position. It is set to become smaller as it approaches the fixed part (the pair of power feeding parts 45, 46 or the pair of dummy terminals 45d, 46d).

  FIG. 12 is a horizontal sectional view of the heater unit 30 before the temperature rise according to the present embodiment. According to FIG. 12, the distance (B in the figure) between the heating element 42 and the inner wall of the heat insulating body 33 is the central position between the pair of power feeding portions 45, 46 and the pair of dummy terminals 45d, 46d, respectively. It is configured to be maximum. The distance between the heating element 42 and the inner wall of the heat insulating body 33 is configured to gradually decrease from the center position toward the power feeding units 45 and 46 or the dummy terminals 45d and 46d. That is, B> A and B> C in the figure.

  In this state, when the heating element 42 is heated to a temperature at the time of substrate processing, for example, each part of the heating element 42 expands in the direction shown in FIG. 14 due to thermal expansion. FIG. 14 shows the displacement direction and displacement amount of each part of the heating element 42 by the direction and length of the arrow, respectively. Since the heating element 42 is fixed at two locations by the pair of power feeding parts 45 and 46 and the pair of dummy terminals 45d and 46d, each part of the heating element 42 is an area near the pair of power feeding parts 45 and 46. The region is displaced so as to swell outward (that is, to extend up and down in the drawing) starting from each of (a region indicated by reference symbol A2a) and a region in the vicinity of the pair of dummy terminals 45d and 46d (region indicated by reference symbol A2b). The amount of displacement of the heating element 42 increases as it approaches the center position (upper and lower ends in the figure) between the pair of power supply portions 45 and 46 and the pair of dummy terminals 45d and 46d, and is maximum at the intermediate position. Become.

  As a result, at least when the heating element 42 is in the temperature state during substrate processing, the distance between the heating element 42 and the inner wall of the heat insulating body 33 is the same distance in the circumferential direction of the heating element 42. FIG. 13 is a horizontal cross-sectional view of the heater unit 30 after temperature increase (in the temperature state during substrate processing) according to the present embodiment. As shown in FIG. 13, when at least the heating element 42 is in a temperature state during substrate processing, the distance between the heating element 42 and the inner wall of the heat insulating body 33 becomes equal over the circumferential direction of the heating element 42 due to thermal expansion. In the figure, A≈B≈C.

  According to this embodiment, in addition to the effects shown in the first embodiment, one or more of the following effects (a) to (c) are exhibited.

(A) According to the present embodiment, the maximum displacement amount of the heating element 42 can be reduced. As a result, the contact between the heating element 42 and the heat insulator 33 can be prevented more reliably.

FIG. 9 is a schematic view illustrating the measurement result regarding the thermal expansion of the heating element according to the first embodiment, and FIG. 15 illustrates the measurement result regarding the thermal expansion of the heating element 42 according to the second embodiment. FIG. In the evaluations shown in FIG. 9 and FIG. 15, the annular heating element 42 having a diameter φ of 481 mm at room temperature (20 ° C.) is heated to 1220 ° C., which is the substrate processing temperature. The amount of displacement was measured. The heating element 42 was formed in a serpentine shape by Kanthal APM (registered trademark) having a linear expansion coefficient of 15 × 10 ⁻⁶ in a temperature range of 20 ° C. to 1250 ° C. In addition, the extension amount of the outer periphery of the heating element 42 due to the temperature rise is (length of the heating element 42) × (1250-20) × 15 × 10 ⁻⁶ mm.

  As a result, in the heating element 42 in the first embodiment, the diameter φ increased from 481 mm to 490.2 mm. Further, as shown in the drawing, the amount of positional deviation of each part of the heating element 42 gradually increases as the distance from the pair of power feeding parts 45 and 46 increases (3.8 mm, 6.5 mm, 8. 6 mm), the maximum distance from the pair of power feeding portions 45 and 46 was 9.2 mm. It should be noted that the position farthest from the pair of power feeding portions 45 and 46 is not displaced in the circumferential direction (tangential direction) but displaced only in the radial direction.

  On the other hand, in the heating element 42 in the second embodiment, the distance between the fixing portions (the pair of power feeding portions 45 and 46 or the pair of dummy terminals 45d and 46d) gradually increases and becomes a central position between the adjacent fixing portions. The maximum value is 7.5 mm at (a central position between the pair of power feeding units 45 and 46 and the pair of dummy terminals 45d and 46d). That is, according to the present embodiment, the maximum displacement amount of the heating element 42 can be reduced by about 20% compared to the first embodiment. Note that, at the central position where the displacement amount is maximum, the positional deviation in the radial direction is mainly performed without the positional deviation in the circumferential direction (tangential direction).

(B) According to the present embodiment, the connection location with the pair of power feeding portions 45 and 46 is fixed, and the opposite side is further fixed with the pair of dummy terminals 45d and 46d. Therefore, the displacement direction of each part of the heat generating element 42 can be made to substantially coincide with the radial direction of the heat generating element 42 (direction perpendicular to the inner wall of the heat insulating element 33) as shown in FIG. In particular, at the central position where the displacement is maximum (the central position between the pair of power feeding portions 45 and 46 and the pair of dummy terminals 45d and 46d), the position is not displaced in the circumferential direction (tangential direction), and the radial direction It is possible to shift the position only. As a result, even when a bridge-type or T-shaped pin member is additionally provided as a fixed portion at the center position, contact / interference between the heating element 42 and the pin member due to thermal expansion can be suppressed. That is, according to the present embodiment, it is possible to further increase the holding strength of the heating element 42 while preventing the heating element 42 from being deformed, damaged, short-circuited, or the like.

In the first embodiment in which the opposite side of the connection portion with the power feeding units 45 and 46 is not fixed, as illustrated in FIG. 8, for example, a position (first position) shifted by 90 ° from the pair of power feeding units 45 and 46. 2), the displacement direction of the heating element 42 in the central position between the pair of power feeding portions 45, 46 and the pair of dummy terminals 45d, 46d does not coincide with the radial direction of the heating element 42, and is tangential. Slightly closer to the direction. Therefore, if the above-described pin member is additionally provided at a position shifted by 90 ° from the pair of power supply portions 45 and 46 without being fixed by the pair of dummy terminals 45d and 46d, Contact / interference with the pin member occurs, and the heating element 42 is deformed, damaged, or short-circuited.

(C) According to the present embodiment, since the displacement direction of each part of the heating element 42 and the radial direction of the heating element 42 substantially coincide with each other, for example, a bridge-type or T-shaped holding member is additionally provided as a fixed part. Even in this case, it is not necessary to provide a notch (elongation allowance hole) on the heating element 42 side to avoid contact / interference between the heating element 42 and the holding member. For this reason, it is possible to avoid a decrease in the strength of the heating element 42 and a decrease in the amount of heat generation. If the above-described pin member is provided at a position shifted by 90 ° from the pair of power supply portions 45 and 46 without being fixed by the pair of dummy terminals 45d and 46d, the heating element 42 and the holding member are brought into contact with each other. -In order to avoid interference, it is necessary to provide a notch, and there is a possibility that the strength of the heating element 42 and the amount of heat generation may be reduced.

<Other embodiments>
As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, It can change variously in the range which does not deviate from the summary.

  For example, in the above-described embodiment, the pair of power feeding units 45 and 46 and the pair of dummy terminals 45d and 46d are described as examples of the fixing unit that fixes the heating element 42 to the inner wall of the heat insulating body 33. Is not limited to such a form. That is, these members do not necessarily have to be paired. Further, for example, a pin member fixed to the inner wall of the heat insulating body 33 may be used as the fixing portion. FIG. 11A is a partially enlarged view around a bridge-type pin member 45b as a modified example of the fixing portion, and FIG. 11B is a side view of the enlarged portion. Although not shown, a T-shaped pin member or an L-shaped pin member can be used as the fixing portion.

  Further, for example, in the above-described embodiment, the place where the heating element 42 is fixed by the fixing portion is one place or two places. However, the present invention is not limited to this case, and may be fixed at, for example, three or more places. Good. Even in this case, at least when the heating element is in a room temperature state, the distance between the heating element and the inner wall of the heat insulator becomes maximum at the central position between the adjacent fixing parts, and as the fixing part approaches the fixing part from the center position. Make it smaller. As the number of fixing points is increased, the maximum displacement amount can be reduced, and the holding strength of the heating element 42 can be improved. Note that the plurality of fixing portions may be arranged at equal intervals over the circumferential direction of the heating element 42.

  In the above case, the plurality of fixing portions may be unified by penetrating members such as a pair of power feeding portions 45 and 46 and a pair of dummy terminals 45d and 46d, or a pin member such as a bridge-type pin member 45b. May be unified, or these may be mixed.

  Further, for example, the present invention is not limited to the case where the upper and lower ends of the heating element 42 are provided with a crest (projection) 42a and a trough (cutout) 42b. That is, the heating element 42 is not limited to being formed in a meandering shape (wave shape), and may be formed in a long shape.

The present invention is not limited to a semiconductor manufacturing apparatus, and can be suitably applied to an apparatus for processing a glass substrate such as an LCD apparatus. Further, the configuration of the process chamber is not limited to the above-described embodiment. That is, the specific content of the substrate processing is not questioned, and it may be processing such as annealing processing, oxidation processing, nitriding processing, and diffusion processing as well as film forming processing. The film formation process may be, for example, a process for forming a CVD, PVD, oxide film, or nitride film, or a process for forming a film containing a metal. Furthermore, it may be an exposure process performed by photolithography or a coating process of a resist solution or an etching solution.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

According to one aspect of the invention,
A heating element formed in an annular shape;
A heat insulator provided to surround the outer periphery of the heating element;
A fixing unit for fixing the heating element to the inner wall of the heat insulator,
Provided is a heating device in which the distance between the heating element and the inner wall of the heat insulator is set to increase as the distance from the fixing portion increases at least when the heating element is at room temperature.

Preferably,
A plurality of the fixing portions are provided along the circumferential direction of the heating element,
At least when the heating element is at room temperature, the distance between the heating element and the inner wall of the heat insulating body is set so as to decrease from the central position between the adjacent fixing parts toward the fixing part. .

Also preferably,
At least when the heating element is at room temperature, the distance between the heating element and the inner wall of the heat insulating body is set to be maximum at the center position between the adjacent fixing portions.

Also preferably,
The distance between the heating element and the inner wall of the heat insulating body is set to be equal over the circumferential direction of the heating element at least when the heating element is in a temperature state during heat treatment.

Also preferably,
The plurality of fixing portions are arranged at equal intervals over the circumferential direction of the heating element.

Also preferably,
At least one of the fixing portions is configured as a pair of power feeding portions that pass through the heat insulating body and are fixed to the heat insulating body and connected to both ends of the heating element.

Also preferably,
At least one of the plurality of fixed portions is configured as a penetrating member that penetrates the heat insulator and is fixed to the heat insulator.

Also preferably,
At least one of the plurality of fixing portions is configured as a pin member that is fixed to the inner wall of the heat insulator.

According to another aspect of the invention,
An annular heating element, a heat insulator provided so as to surround the outer periphery of the heat generator, and a fixing portion for fixing the heat generator to an inner wall of the heat insulator. A step of carrying the substrate into a processing chamber provided inside;
And heating the heating element to heat and process the substrate in the processing chamber,
When at least the heating element is at room temperature, the distance between the heating element and the inner wall of the heat insulator is set to increase as the distance from the fixing portion increases.
A method for manufacturing a semiconductor device is provided.

1 Wafer (substrate)
14 Processing chamber 30 Heater unit (heating device)
33 Heat Insulator 42 Heating Element 42a Mountain 42b Valley 45, 46 Power Feed (Fixed)
45d, 46d Dummy terminal (fixed part)
45b Pin member (fixed part)

Claims (3)

A heating element formed in an annular shape;
A heat insulator provided to surround the outer periphery of the heating element;
A fixing unit for fixing the heating element to the inner wall of the heat insulator,
At least when the heating element is at room temperature, the heating apparatus is set such that a distance between the heating element and an inner wall of the heat insulating body increases as the distance from the fixing portion increases. A plurality of the fixing portions are provided along the circumferential direction of the heating element,
At least when the heating element is at room temperature, the distance between the heating element and the inner wall of the heat insulating body is set so as to decrease from the central position between the adjacent fixing parts toward the fixing part. The heating apparatus according to claim 1. An annular heating element, a heat insulator provided so as to surround the outer periphery of the heat generator, and a fixing portion for fixing the heat generator to an inner wall of the heat insulator. A step of carrying the substrate into a processing chamber provided inside;
And heating the heating element to heat and process the substrate in the processing chamber,
A method of manufacturing a semiconductor device, characterized in that at least when the heating element is at room temperature, a distance between the heating element and an inner wall of the heat insulator is set to increase as the distance from the fixing portion increases.

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