JP3641193B2 - Vertical heat treatment apparatus, heat treatment method, and heat insulation unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a vertical heat treatment apparatus and a heat treatment method.And thermal insulation unitAbout.
[0002]
[Prior art]
A vertical heat treatment apparatus is known as one of semiconductor device manufacturing apparatuses. This heat treatment apparatus is of a batch type in which a large number of wafers are heat treated at once, and FIG. 14 shows a schematic view of an apparatus for performing low pressure CVD. Reference numeral 1 denotes a wafer boat. The wafer boat 1 holds a large number of wafers W in a shelf shape and is carried into a reaction vessel comprising a double-structured reaction tube 11 and a cylindrical manifold 12 by an elevator (not shown). The At this time, the reaction vessel is airtightly closed by the lid 10. The inside of the reaction vessel is heated to a predetermined temperature by a heater 13 surrounding the reaction tube 11 and is reduced to a predetermined pressure by an exhaust tube 14. Then, a film forming gas is supplied from the lower side of the reaction vessel through the gas supply pipe 15, is decomposed into thin film components and is deposited on the wafer W, and the remaining gas is supplied from the ceiling of the inner pipe 11a to the inner pipe 11a and the outer pipe. It descends the space between 11b.
[0003]
Under the wafer boat 1, for example, a thermal insulation unit 16 in which quartz wool or the like is accommodated in a cylindrical body made of quartz is interposed to insulate the atmosphere in which the wafer W is placed from the outside of the lid body 10 to keep the thermal insulation. Further, several dummy wafers W called side wafers are placed on the lower end side of the wafer boat 1 without placing the product wafers W.
[0004]
[Problems to be solved by the invention]
By the way, the heat capacity of the heat retaining unit 16 is set to be large so that the heat of the atmosphere in which the wafer W is placed is not released outside as much as possible. For this reason, when the temperature of the processing atmosphere is raised to the target processing temperature to stabilize the temperature, the temperature rise of the heat retaining unit 16 is delayed, and heat flows from the processing atmosphere to the heat retaining unit 16 side. As a result, the time during which the temperature stabilizes (recovery time) is long, which causes a decrease in throughput. Furthermore, unless a sufficiently long recovery time is taken, the reproducibility for each batch process is poor.
[0005]
Further, the heat retaining unit 16 blocks the heat flow between the processing atmosphere and the outside of the reaction vessel. However, since the lower part of the wafer placement area of the wafer boat 1 has a large amount of heat radiation, Side wafers (dummy wafers) are placed from the lowermost stage to several upper stages, and thus the area for placing the product wafer W must be narrowed. Therefore, even if the number of wafers that can be stored in the wafer boat 1 is increased, the number of processed product wafers W per batch processing is reduced, which eventually hinders improvement in throughput.
[0006]
Furthermore, the film forming gas introduced into the reaction vessel through the gas supply pipe 15 rises along the side of the heat insulating unit 16, but the temperature of the heat insulating unit 16 is low. The amount of unreacted gas reaching the processing atmosphere where W is placed increases. For this reason, the amount of gas to be decomposed in the processing atmosphere increases, and the amount of active species generated varies depending on the location. This is reflected in the film thickness of the wafer W, and between wafers W and within the wafer W surface. This is one of the causes of the poor uniformity of film thickness.
[0007]
In order to solve such problems, the present inventor is considering the provision of a heating element unit in the heat retaining unit. In realizing this, how should the temperature control of the heating element unit be performed? There are problems such as how to suppress the heat radiation from the heating element unit to the lid, and what kind of structure is appropriate when the holder is rotated.
[0008]
The present invention has been made under such circumstances, and its purpose is to quickly stabilize the temperature of the processing atmosphere of the vertical heat treatment apparatus and to suppress heat radiation from the processing atmosphere to the outside. An object of the present invention is to provide an appropriate configuration when a heating element unit is used as the means for realizing the above.
[0009]
[Means for Solving the Problems]
The present invention allows a holder supported on a lid to hold a large number of objects to be processed in a shelf shape, carries the holder into the reaction vessel from below, and lowers the lower end of the reaction vessel with the lid. The present invention is intended for a vertical heat treatment apparatus that hermetically seals and heat-treats the object to be processed in a heated atmosphere inside the reaction vessel.
[0010]
  The present invention provides a planar heating element unit provided between the lid and the holder so as to face the bottom of the holder, and encapsulating a resistance heating element in ceramics,
And a heat shield plate provided on the lower side of the heating element unit and having a black film layer formed on one surface of the quartz plate. Instead of forming the black film layer on one surface of the quartz plate, the heat shield plate may be configured by enclosing the black film layer in a quartz plate body.
[0011]
  According to this invention, since the heating element unit is provided on the lower side of the holder, the amount of heat dissipated from the processing atmosphere in the reaction vessel to the lower side is reduced, so that the processing atmosphere is quickly stabilized at the target temperature. It is possible to secure a wide processing area where the temperature can be stabilized.At the same time, the heat insulation effect and the thermal responsiveness are improved.
[0015]
According to still another aspect of the present invention, when the holder is configured to rotate, it is configured to penetrate the central portion of the heating element unit and be divided into an upper side and a lower side, and rotate the holder around the vertical axis. Therefore, it is possible to provide a configuration including a rotation shaft for rotation and a rotation drive unit connected to the lower end of the rotation shaft.
[0016]
  MoreIn another invention, a plurality of objects to be processed are held in a shelf shape on a holder supported on a lid, and the holder is carried into the reaction vessel from below and the lower end of the reaction vessel is covered by the lid. In a heat retaining unit used in a vertical heat treatment apparatus that heat-treats an object to be processed with the inside of the reaction vessel being heated in a heated atmosphere,
  A ring-shaped bottom surface portion and a ring-shaped top surface portion placed on the lid are connected to and opposed to each other by a first protective tube, and upper and lower portions of the first protective tube are opened to the upper surface portion and the bottom surface portion, respectively. A heat insulating unit,
  The hollow ring-shaped body has a shape in which the lower surface is opened, and the inner space is partitioned from the outer space by being detachably mounted with its lower end in contact with the upper surface of the heat insulating unit. A cover body;
  A heating element unit that is disposed in the cover body and encloses a heater wire made of a high-purity carbon material in a ring-shaped quartz plate;
  A third protective tube connected to the lower surface side of the quartz plate and inserted with a power supply line for supplying power to the heater wire,
  The third protective tube is inserted into the first protective tube and extends from below the first protective tube;
  The opening at the center of each of the heat insulating unit, the cover body, and the heating element unit is for a rotating shaft for rotating the holder to pass therethrough.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an overall configuration diagram showing an embodiment of a vertical heat treatment apparatus of the present invention, and FIG. 2 is an overview of the vertical heat treatment apparatus. First, the outline of the apparatus will be briefly described with reference to these drawings. In FIG. 1, reference numeral 2 denotes a reaction tube having a double tube structure made of, for example, quartz made of an inner tube 2 a and an outer tube 2 b, and a metal tubular manifold 3 is provided on the lower side of the reaction tube 2. ing.
[0018]
The inner pipe 2 a has an upper end opened and is supported on the inner side of the manifold 3. The outer tube 2 b is closed at the upper end, and the lower end is airtightly joined to the upper end of the manifold 3. In this example, a reaction vessel is constituted by the inner tube 2a, the outer tube 2b, and the manifold 3. 31 is a base plate.
[0019]
In the reaction tube 2, a large number of, for example, 126 wafers W to be processed are placed in a shelf shape on a wafer boat 21 that is a holder in a horizontal state and spaced apart vertically. As shown in FIG. 2, the wafer boat 21 is configured by providing a plurality of support columns 24 between the top plate 22 and the bottom plate 23, and forming grooves for holding the peripheral edge of the wafer W in the support columns 24. The wafer boat 21 is held on the lid 32 through the installation area of the heat retaining unit 4. The heat retaining unit 4 will be described later in detail. The lid 32 is mounted on a boat elevator 33 for carrying the wafer boat 21 into and out of the reaction tube 2, and when it is at the upper limit position, the lower end opening of the manifold 3, that is, the reaction tube 2 and the manifold. 3 has the role of closing the lower end opening of the reaction vessel.
[0020]
A heater 25 made of, for example, a resistance heating body is provided around the reaction tube 2 so as to surround the reaction tube 2. Although not shown in FIG. 1, a heat insulating layer is provided around the heater 25, and an exterior body is provided on the outer side thereof, and these constitute the heating furnace 20 (see FIG. 2).
[0021]
A plurality of gas supply pipes are provided around the manifold 3 so that a plurality of processing gases can be supplied into the inner pipe 2a. In FIG. 1, one of the gas supply pipes 34 is shown, and this gas supply pipe 34 is connected to a gas supply source 35 via a valve V1, a flow meter MFC and a valve V2. Further, an exhaust pipe 36 is connected to the manifold 3 so that the space between the inner pipe 2a and the outer pipe 2b can be exhausted, and the inside of the reaction tube can be maintained in a predetermined reduced pressure atmosphere by a vacuum pump 37. Yes.
[0022]
Next, the said heat retention unit 4 and the site | part relevant to this are demonstrated, referring FIGS. 3-5. The heat retaining unit 4 includes a heat insulating unit 40 made of ceramic, for example, quartz. The heat insulating unit 40 has a circular upper surface portion 41 and a bottom plate portion 42 (in FIG. 5, the outer peripheral portion of the bottom plate portion 42 is omitted). And three struts 43 (see FIG. 4) that connect the upper surface part 41 and the bottom plate part 42 and are provided at intervals in the circumferential direction. A large number of grooves 44 (see FIG. 5) are formed on each of the three support columns 43, and quartz fins 45 (FIG. 4) serving as heat insulating members are formed in the grooves 44 of the three support columns 43. The quartz fins 45 are arranged in multiple stages. The quartz fin 45 is for suppressing heat from the upper side from radiating to the lid 32 side. The heat insulating member is not limited to the quartz fin 45 but may be a foamed quartz block.
[0023]
Further, a first protective tube 46 and a second protective tube 47 are provided between the upper surface portion 41 and the bottom surface portion 42 of the heat insulating unit 40 at intervals in the circumferential direction. Both ends open to the upper surface portion 41 and the bottom surface portion 42, respectively.
[0024]
On the upper surface portion 41 of the heat insulating unit 40, a heat shield plate 48 (not shown in FIG. 4) for suppressing heat radiation to the lid 32 side is placed. For example, as shown in FIG. 6, the heat shield plate 48 is configured by sealing a black film layer 48b made of carbon, for example, in a transparent quartz plate 48a. The black film layer 48b may be a titanium film, a silicon carbide film, or the like, and may be formed on one side of the quartz plate 48a even if it is not enclosed in the quartz plate 48a.
[0025]
For example, a planar heating element unit 5 is provided above the heat shield plate 48 through a gap. The heating element unit 5 is configured by enclosing a resistance heating element with few metal impurities in ceramics such as quartz. In this example, as shown in FIG. 7, for example, a quartz circle having a thickness of about 8 mm is used. A heater wire 52 made of a high-purity carbon material is spirally arranged in a plate-like body (quartz plate) 51. Further, quartz may be interposed between the heater wires 52 and 52 adjacent to each other. In this case, the heater wire 52 is wired between spiral partition walls made of quartz. The heating element unit 5 is preferably the same size or larger than the wafer W in order to increase the heat retaining effect.
[0026]
A third protective tube 53 is connected to the lower surface of the peripheral edge of the quartz plate 51 of the heating element unit 5, and the power supply line 54 for supplying power to the heater wire 52 is shown in FIG. As shown in FIG. 3, the third protective tube 53 is connected to the connection portion, and is inserted into the protective tube 53 from there. Although not shown in detail in the figure, each of the feeder lines 54 passes through the protective tube 53 in a state of being enclosed in a thin quartz tube. The third protective tube 53 is inserted into the first protective tube 46 opened in the upper surface portion 41 of the heat insulating unit 40, and further penetrates the lid body 32 to the lower surface side of the lid body 32. Is fixed. Therefore, the third protective tube 53 also serves as a support for the heating element unit 5.
[0027]
Further, in the center of the upper surface portion 41 and the bottom surface portion 42 of the heat insulating unit 40, the quartz fin 45, the heat shield plate 48, and the heating element unit 5, a hole through which a rotation shaft, which will be described later, for rotating the wafer board 21 passes. 41a, 42a, 45a, 48a and 5a are formed, respectively. On the upper surface portion 41, for example, a cylindrical (ring-shaped) quartz cover body 55 having a hole portion 55 a formed in the center portion, which covers the heating element unit 5 and the heat shield plate 48, is placed. (Removably provided). Accordingly, the heating element unit 5 is placed in a space surrounded by the cover body 55 and the upper surface portion 41 and is isolated from the processing atmosphere, so that reaction products are less likely to adhere.
[0028]
On the other hand, the wafer boat 21 passes through the holes 55a, 48a, 41a, 45a, 42a in the center of the cover body 55 and the heat insulating unit 4 and penetrates to the lower side of the cover body 32. It is mounted via a table 27 on the top. As shown in FIGS. 3 and 8, the rotary shaft 26 can be separated vertically, and an upper rotary shaft 26 </ b> A having a concave portion SA formed at the lower end and a lower rotary shaft 26 </ b> B formed with a convex portion SB at the upper end. The concave portion SA and the convex portion SB are fitted. The upper rotating shaft 26A and the lower rotating shaft 26B are made of, for example, quartz and metal, respectively, and in consideration of the thermal expansion coefficients of both materials, the two are in a close fitting state at the process temperature, and there is no backlash. Set the dimensions as follows. Further, as shown in FIG. 8, for example, a temperature adjusting means such as a heater 28 is embedded in the lower rotating shaft 26B, and the heat generation amount of the heater 28 is adjusted to control the temperature of the lower rotating shaft 26B. Thus, the thermal expansion of the metal may be adjusted.
[0029]
In the second protective tube 47 provided in the heat insulation unit 4, a first temperature detection unit 60 is inserted, in which a thermocouple and its conducting wire are enclosed in a quartz tube, and its tip is L-shaped. It is bent into a mold and located between the heating element unit 5 and the heat shield plate 48. The sensor portion of the thermocouple at the tip in the first temperature detection unit 60 constitutes the first temperature detection portion 61. The base end side of the first temperature detection unit 60 penetrates the lid body 32 in an airtight manner.
[0030]
Further, a second temperature detection unit 70 in which a thermocouple and its conducting wire are enclosed in a quartz tube is inserted into the lid 32 in an airtight manner, and its tip is bent into an L shape. In the vicinity of the wafer W, for example, in the vicinity of the lower side of the wafer boat 21. The sensor part of the thermocouple at the tip in the second temperature detection unit 70 constitutes the second temperature detection part 71. In fixing the temperature detection unit 60 (70) to the lid body 32, for example, a protrusion 60a is formed on the quartz tube of the temperature detection unit 60 (70) as shown in FIG. The shape of 60b is adapted to the cross-sectional shape of the quartz tube including the projection 60a, thereby preventing rotation and positioning of the quartz tube.
[0031]
FIG. 10 is a diagram showing a temperature control system of the heating element unit 5, and the control unit 62 that controls the temperature of the heating element unit 5 is the temperature of both the first temperature detection unit 61 and the second temperature detection unit 71. The power supply of the heating element unit 5 is controlled based on the detection signal. Although the control unit 62 is schematically illustrated in the figure, in practice, the power source unit of the heating element unit 5, the control circuit for controlling the phase of the supplied power, for example, and the phase control signal based on both the temperature detection signals The calculation part etc. which create are included. That is, in this embodiment, the temperature control of the heating element unit 5 is performed based on the temperature near the heating element unit 5 and the temperature near the wafer W.
[0032]
Next, the operation of the above embodiment will be described. Here, an example of forming an oxide film called HTO (High Temperature Oxide) by CVD processing is given as an example of specific processing. First, a predetermined number of wafers W to be processed are held in a shelf shape on the wafer boat 21, and the boat elevator 33 is lifted to carry it into the reaction vessel. When the wafer boat 21 is loaded, the processing atmosphere of the reaction vessel is maintained at, for example, about 600 ° C. The wafer boat 21 is loaded and the lower end opening of the reaction vessel (specifically, the lower end opening of the manifold 3) is covered by the lid 32. After the blockage, the temperature of the processing atmosphere is raised to, for example, about 800 ° C. by the heater 25 and the inside of the reaction vessel is depressurized to a predetermined degree of vacuum by the vacuum pump 37 through the exhaust pipe 36.
[0033]
On the other hand, while the wafer boat 21 is waiting on the lower side of the reaction vessel, in order to avoid the influence of the wind from the fan filter generated in the loading area (the room for carrying in and out), for example, The temperature control of the heat generating unit 5 is performed using only the first temperature detecting unit 61 without using the second temperature detecting unit 71, and the heat generating unit 5 is maintained at around 100 ° C., for example. When the loading of the wafer board 21 is started, the heating element unit 5 starts to raise the temperature (the temperature setting value is increased), and the temperature of the heating element unit 5 is set to be higher than the temperature of the processing atmosphere at the time of film formation, for example. Raise the temperature to a slightly higher temperature. The time when the heating element unit 5 and the processing atmosphere reach the target temperature is approximately the same timing, for example. After the wafer boat 21 is carried into the reaction vessel, the temperature control of the heating element unit 5 is performed based on the temperature detection values of both the first temperature detection unit 61 and the second temperature detection unit 71. Specifically, assuming that the detected values of the temperature detectors 61 and 71 are T6 and T7, respectively, the ratio is A, and T6 · A + T7 (1−A) is the ratio control temperature. Then, the temperature of the wafer W is appropriately controlled by adjusting the value of the ratio A or adjusting the temperature setting value.
[0034]
Thereafter, the process waits for the time for temperature stabilization (recovery time) without performing any treatment, and then, from the two gas supply pipes 34 (only one is shown in FIG. 1 as described above), dichlorosilane. While supplying (SiH2 Cl2) gas and dinitrogen monoxide (N2 O) gas into the reaction vessel (reaction tube 1 and manifold 3), the pressure in the reaction vessel is maintained at a predetermined degree of vacuum, for example. At this time, the rotating shaft 26 is rotated to rotate the wafer boat 21.
[0035]
Here, since the temperature in the vicinity of the surface of the heating element unit 5 is set to, for example, about 840 ° C., the temperature around the heating element unit 5 and a little lower side thereof is higher than the temperature of the processing atmosphere near 800 ° C. For this reason, the dichlorosilane gas and the nitric oxide gas supplied to the lower side of the reaction vessel are decomposed when passing by the heat insulating unit 4 and diffused into the processing atmosphere in the state where the decomposition has progressed. Active species are deposited on the silicon oxide film. Thereafter, the electric power of the heater 25 is controlled to lower the temperature in the reaction vessel, the electric power supplied to the heating element unit 5 is set to zero, and the heating element unit 5 is lowered. For example, when the temperature of the processing atmosphere reaches 600 ° C. The wafer boat 21 is lowered.
[0036]
According to the above embodiment, the following effects are obtained.
[0037]
(1) Since the heating element unit 5 is provided between the wafer boat 21 and the lid 32, the amount of heat radiated to the outside from the processing atmosphere via the heat retaining unit 4 is reduced. Since the heat retaining unit 4 includes the heating element unit 5, the heat retaining property is good. For this reason, since the heat capacity may be small, the heat retaining unit 4 as a whole is heated at a high speed. For this reason, after the temperature of the processing atmosphere reaches the target temperature, a time (recovery time) for stabilizing the temperature to that temperature can be shortened, and the throughput can be improved. Further, since the variation in recovery time for each batch process is reduced, the reproducibility of the process is improved.
[0038]
(2) Since the heat retaining effect of the heat retaining unit 4 is large as described above, a region with high temperature uniformity spreads downward, so that the side wafer is placed on the lower part of the wafer boat 21 because the temperature is low until now. Product wafers can be placed in the unavoidable areas, and the number of processed wafers per batch can be increased, so that throughput is also improved in this respect.
[0039]
(3) Since the film forming gas supplied into the reaction vessel through the gas supply pipe 34 is heated by the heating element unit 5 and decomposed to some extent before reaching the processing atmosphere, the amount of unreacted gas in the processing atmosphere is small. Become. As a result, the uniformity of the concentration of the active species is increased between the wafers W arranged on the wafer board 21 and in the plane of each wafer W, and the film thickness is uniform between the wafers W and in the wafer W plane. Becomes higher.
[0040]
(4) After the wafer boat 21 is loaded into the reaction vessel, the temperature of the heating element unit 5 is controlled based on the temperature detection value near the heating element unit 5 and the temperature detection value near the wafer W. Therefore, there is no possibility that an excessive load is applied to the heating element unit 5 while the temperature of the wafer W is rapidly raised. For example, when only the temperature near the heating element unit 5 is detected, the temperature rise control by the heating element unit 5 is insufficient even though the temperature of the wafer W is low, or conversely the temperature near the wafer W In the case where only the load is detected, there is a possibility that the service life may be shortened by trying to further increase the temperature of the wafer W in order to increase the temperature of the wafer W even though the load of the heating element unit 5 is close to the limit. The temperature control of this embodiment is superior to the case of using one temperature detection value.
[0041]
(5) Furthermore, when the wafer boat 21 is waiting in the loading area below the reaction vessel, the temperature detection of the first temperature detection unit 61 which is covered with the cover body 55 and is not affected by the wind. Since the heating element unit 5 is controlled based on the value, stable temperature control can be performed. If the temperature control is unstable, when the heating element unit 5 enters the reaction vessel, the start temperature of the temperature stable region in the reaction vessel changes, and thus the curve also changes. The reproducibility of becomes worse. In addition, the temperature of the heating element unit 5 temporarily rises in the loading area, which may adversely affect the mechanical system such as the transport mechanism.
[0042]
(6) Since the heat shield plate 48 is provided on the lower side of the heat generating unit 5, it is possible to suppress the heat from the heat generating unit 5 from escaping to the lower side, so that high heat retention can be obtained and heat insulation can be achieved. The unit 40 can be made smaller or eliminated. Accordingly, since the heat capacity of the heat insulating unit 40 is reduced, the temperature of the lower wafer W can be raised quickly, and the throughput can be improved. Moreover, since the input power of the heating element unit 5 can be reduced, it can be heated efficiently.
[0043]
(7) By configuring the rotary shaft 26 of the wafer boat 21 so as to be vertically separated, for example, when the upper rotary shaft 26A made of quartz is cleaned or replaced, it can be extracted upward, and disassembly work Is easy.
[0044]
In the above, it is preferable to control the temperature of the heating element unit 5 only by the first temperature detection unit 61 when the wafer board 21 is in the loading area. However, even if the second temperature detection unit 71 is used in combination. Good. The first temperature detector 61 may be provided integrally with the heating element unit 5. In this case, the first temperature detection unit 61 may be provided in the heating element unit 5, or the quartz plate 51 of the heating element unit 5. The quartz tube of the first temperature detection unit 60 may be welded to the outer surface of the first temperature detection unit 60. The first temperature detection unit may include a temperature detection unit for preventing excessive temperature rise in addition to the first temperature detection unit 61. In addition, you may use a radiation thermometer etc. as the temperature detection parts 61 and 71 and the temperature detection part for excessive temperature rise prevention.
[0045]
Furthermore, when performing the temperature control of the heating element unit 5, it is preferable to use both the first temperature detection unit 61 and the second temperature detection unit 71 as described above during the process. The case where only the detection unit 61 is used is also included.
Furthermore, the heating element unit 5 may divide the resistance heating element 52 (heating area) into a plurality of areas and perform temperature control (so-called zone control) for each divided area. FIG. 11 shows an example of the division pattern of the resistance heating element 52. FIG. 11 (a) shows the heating element unit 5 divided into four in the circumferential direction, and FIG. 11 (b) shows the heating element unit 5. FIG. 11C shows the heating element unit 5 that is divided into four concentric circles in the circumferential direction. As an example of concentric division, the resistance heating element 52 is described in a ring shape for convenience of illustration. However, actually, for example, the resistance heating element 52 is divided into four concentric circles, and the resistance heating element 5 is arranged in a predetermined arrangement pattern for each divided region. It may be arranged with-.
[0046]
FIG. 12 shows an example of a control system when the heat generating unit 5 divides the heat generating area into four parts P1 to P4, and 52-1 to 52-4 are assigned to the respective divided areas P1 to P4. The resistance heating elements Q1 to Q4 are first temperature detectors assigned to the divided areas P1 to P4, and 81 to 84 are control parts assigned to the divided areas P1 to P4. In this example, each of the control units 81 to 84 generates heat from the resistance heating elements P1 to P4 based on the temperature set value, the temperature detection values of the first temperature detection units Q1 to Q4, and the temperature detection value of the second temperature detection unit. The amount is controlled. According to such an example, it is possible to perform fine temperature control such that the heat retention in the circumferential direction can be made uniform, or the heat generation outside can be increased to make the heat insulation in the surface uniform.
[0047]
In the present invention, as shown in FIG. 13, as a safety measure for preventing a fire when the heating element unit 5 is overheated and preventing human and material accidents, for example, the lower surface side of the heating element unit 5 and the lid It is preferable to provide temperature detecting portions 91, 92, 93 for preventing an excessive temperature rise in the lower surface side of the body 32 or in the loading area, and to stop the power supply of the heating element unit 5 based on the temperature detection signal. . Reference numerals 94 and 95 denote temperature detectors for preventing overheating of the heater of the heating furnace 20.
[0048]
The present invention is not limited to being applied to a low pressure CVD apparatus, but can be applied to a so-called oxidation and diffusion furnace.
[0049]
【The invention's effect】
According to the present invention, since the heating element unit is provided between the lid of the reaction vessel and the holder of the object to be processed, the time required for temperature stabilization can be shortened. By detecting the temperature in the vicinity of the heating element unit and the temperature in the vicinity of the object to be processed, and controlling the heating element unit based on the detected temperature values, the object to be processed can be quickly heated. Moreover, there is no possibility that an excessive load is applied to the heating element unit.
[Brief description of the drawings]
FIG. 1 is a vertical sectional side view showing an overall configuration of an embodiment of a vertical heat treatment apparatus of the present invention.
FIG. 2 is a perspective view showing an overview of the apparatus.
FIG. 3 is a cross-sectional view showing a heat retaining unit including a heating element unit and a heat insulating unit used in this embodiment.
FIG. 4 is an exploded perspective view showing a heat retaining unit and a rotating shaft.
FIG. 5 is a cross-sectional plan view showing the heat insulating unit.
FIG. 6 is a cross-sectional view showing a heat shield plate.
FIG. 7 is an explanatory view showing a cross section and a plane of a heating element unit.
FIG. 8 is a schematic explanatory view showing a state in which a rotating shaft is disassembled.
FIG. 9 is a perspective view showing a structure in which a quartz tube of a temperature detection unit is attached to a lid.
FIG. 10 is an explanatory diagram showing a temperature control system of the heating element unit.
FIG. 11 is a plan view showing an example in which the resistance heating element of the heating element unit is divided.
FIG. 12 is an explanatory diagram showing a control circuit for controlling the resistance heating element divided in the heating element unit;
FIG. 13 is an explanatory diagram showing an example of the arrangement of a heater for heating a processing atmosphere and a sensor for preventing an excessive temperature rise of a heating element unit.
FIG. 14 is a vertical sectional side view showing a conventional vertical heat treatment apparatus.
[Explanation of symbols]
2 reaction tubes
21 Wafer boat
26 Rotating shaft
26A Upper rotation axis
26B Lower rotation shaft
3 Manifold
32 Lid
4 Thermal insulation unit
40 Thermal insulation unit
46 First protective tube
45 Quartz fins
47 Second protective tube
48 heat shield
5 Heating unit
53 Third protective tube
55 Cover body
61 1st temperature detection part
62 Control unit
71 2nd temperature detection part
P1-P4 divided area
Q1-Q4 1st temperature detection part
81-84 control unit
91-95 Temperature detector for preventing excessive temperature rise

Claims (11)

A holding tool supported on the lid body holds a large number of objects to be processed in a shelf shape, and the holder is carried into the reaction vessel from below and the lower end of the reaction vessel is hermetically closed by the lid body. In a vertical heat treatment apparatus that heat-treats the object to be processed in a heated atmosphere inside the reaction vessel,
A planar heating element unit provided between the lid and the holder so as to face the bottom of the holder, and encapsulating a resistance heating element in ceramics;
A vertical heat treatment apparatus comprising: a heat shield plate provided on a lower side of the heating element unit and having a black film layer formed on one surface of a quartz plate. The heat shield plate instead of black film layer on one surface of the quartz plate are formed, vertically according to claim 1, characterized in that the black film layer is composed enclosed in a quartz plate member Mold heat treatment equipment. A holding tool supported on the lid body holds a large number of objects to be processed in a shelf shape, and the holder is carried into the reaction vessel from below and the lower end of the reaction vessel is hermetically closed by the lid body. In a vertical heat treatment apparatus that heat-treats the object to be processed in a heated atmosphere inside the reaction vessel,
A heating unit provided by being fixed to the lid below the holder, and enclosing a resistance heating element in ceramics,
It is configured to penetrate the central portion of the heating element unit and be divided into an upper side and a lower side, and a rotating shaft for rotating the holder around the vertical axis;
A vertical heat treatment apparatus, comprising: a rotary drive unit connected to a lower end of the rotary shaft; The upper and lower rotary shafts are made of ceramics and metal, respectively, and are provided with temperature adjusting means for adjusting the thermal expansion of the lower rotary shaft and tightly fitting with the upper rotary shaft. The vertical heat treatment apparatus according to claim 3 . Detecting the temperature of the heat generating unit, according to any of claims 1, characterized in that a temperature detecting portion for preventing excessive temperature rise for preventing excessive temperature rise of the heat generating unit 4 Vertical heat treatment equipment. The resistance heating body vertical heat treatment apparatus according to any one of 5 claims 1, characterized in that it consists of carbon material. Vertical heat treatment apparatus according to any one of claims 1, wherein the ceramic resistive heating element is enclosed is quartz 6. The vertical heat treatment apparatus according to any one of claims 1 to 7 , wherein a heat insulating member is provided on a lower side of the heating element unit. A holding tool supported on the lid body holds a large number of objects to be processed in a shelf shape, and the holder is carried into the reaction vessel from below and the lower end of the reaction vessel is hermetically closed by the lid body. In a heat retaining unit used in a vertical heat treatment apparatus that heat-treats an object to be treated in a heated atmosphere in the reaction vessel,
A ring-shaped bottom surface portion and a ring-shaped top surface portion placed on the lid are connected to and opposed to each other by a first protective tube, and upper and lower portions of the first protective tube are opened to the upper surface portion and the bottom surface portion, respectively. A heat insulating unit,
The hollow ring-shaped body has a shape in which the lower surface is opened, and the inner space is partitioned from the outer space by being detachably mounted with its lower end in contact with the upper surface of the heat insulating unit. A cover body;
A heating element unit disposed in the cover body and enclosing a heater wire made of a carbon material in a ring-shaped quartz plate;
A third protective tube connected to the lower surface side of the quartz plate and inserted with a power supply line for supplying power to the heater wire,
The third protective tube is inserted into the first protective tube and extends from below the first protective tube;
The heat insulating unit, wherein the central opening of each of the heat insulating unit, the cover body, and the heating element unit is for a rotating shaft for rotating the holder to pass therethrough. A second protective tube provided so as to connect the upper surface portion and the bottom surface portion of the heat insulating unit and to open the upper and lower surfaces to the upper surface portion and the bottom surface portion, respectively;
The heat retention unit according to claim 9 , further comprising: a temperature detection unit provided on a lower side of the heating element unit in the cover body, the conductor of which is inserted into the second protective tube. Support columns provided in the circumferential direction of the heat insulation unit so as to connect the upper surface portion and the bottom surface portion of the heat insulation unit, and grooves formed at intervals above and below,
The heat retaining unit according to claim 9 or 10 , further comprising a fin that forms a heat insulating member inserted into a groove of the support column.

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