JP2002025995A - Vertical heat treatment equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable vertical heat treatment equipment which performs heat treatment on many semiconductor wafers in a reaction chamber while the wafers are held on a shelf-like holding tool and, at the same time, to widely form a treatment atmosphere having high temperature uniformity. SOLUTION: Between a lid body closing the lower end of the reaction chamber and the holding tool, a heating element unit constituted by enclosing a resistance heat generating wire composed of a high-purity carbon material in a quartz plate is provided, and a feeder protective tube is connected to the lower surface of the outer edge section of the heating element unit by passing the lower end of the protective tube through the lid body. In addition, a heat insulating unit containing a heat insulating member is provided below the heating element unit, and the protective tube and heat insulating unit are supported in a vertically movable state by means of an interlocking plate below the lid body so that the heights of the units may be adjusted. The holding tool is supported rotably to the lid body by a rotating shaft passed through the heating element and heat insulating units.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a vertical heat treatment apparatus.

[0002]

2. Description of the Related 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. 15 is a schematic diagram showing 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 including a double-structured reaction tube 11 and a cylindrical manifold 12 by an elevator (not shown). You. At this time, the reaction vessel is hermetically 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 depressurized to a predetermined pressure by an exhaust pipe 14.
Then, a film forming gas is supplied from the lower side of the reaction vessel through a gas supply pipe 15, decomposed into thin film components and deposited on the wafer W, and the remaining gas is supplied from the ceiling of the inner pipe 11 a to the inner pipe 1.
The space between the outer tube 1a and the outer tube 11b is lowered.

Under the wafer boat 1, an atmosphere in which the wafer W is placed is insulated from the outside of the lid 10 through a heat retaining unit 16 in which a quartz wool or the like is stored in a cylindrical body made of, for example, quartz. In addition, several dummy wafers W called side wafers or the like are placed on the lower end side of the wafer boat 1 without placing the product wafers W thereon.

[0004]

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 to the outside as much as possible. Therefore, when the temperature of the processing atmosphere is raised to the target processing temperature to stabilize the temperature, the heat retaining unit 1
6 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 is stabilized (recovery time) is long, which causes a decrease in throughput. Further, unless a sufficiently long recovery time is taken, the reproducibility of each batch process is poor.

Although the heat flow between the processing atmosphere and the outside of the reaction vessel is cut off by the heat retaining unit 16, the lower part of the wafer mounting area of the wafer boat 1 has a large amount of heat radiation, so that the wafer is radiated. Side wafers (dummy wafers) are placed from the lowermost stage to several stages above the boat 1, so that the mounting area of 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 process is reduced, which hinders an improvement in throughput.

Further, the film forming gas introduced into the reaction vessel through the gas supply pipe 15 rises along the side of the heat retaining unit 16, but the temperature of the heat retaining unit 16 is low. The amount of unreacted gas that reaches the processing atmosphere where the wafer W is placed increases. As a result, the amount of gas 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 wafers W, and between the wafers W and in the wafer W plane. This is one reason that the uniformity of the film thickness is deteriorated.

Therefore, the present inventor has been studying the provision of a heating element unit in the heat retaining unit in order to solve such a problem. In order to realize this, how to attach the heating element unit is performed. However, there are problems such as how to suppress the adhesion of the reaction product to the heating element unit and how to obtain high effectiveness of the heating element unit.

The present invention has been made under such circumstances, and an object of the present invention is to quickly stabilize the temperature of the processing atmosphere of a vertical heat treatment apparatus and to suppress heat radiation from the processing atmosphere to the outside. It is another object of the present invention to provide an appropriate configuration in the case of using a heating element unit as a means for realizing the same.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a plurality of workpieces are held in a shelf on a holder supported on a lid, and the holder is loaded into a reaction vessel from below. The present invention is directed to a vertical heat treatment apparatus in which the lower end of a reaction vessel is hermetically closed by the lid and the inside of the reaction vessel is heated and decompressed to perform a heat treatment on the object.

In one aspect of the invention, a resistance heating element having a small amount of metallic impurities is provided between the lid and the holder and supported on the lid independently of the holder, and is encapsulated in ceramics. The heat generating unit is characterized in that the heat generating unit can be changed in height. Specifically, for example, on the lower side of the heating element unit, a heat insulating member supported by the lid independently of the holder is provided,
It is configured such that the heights of the heating element unit and the heat insulating member can be changed together. As an example of such a configuration, a case where a driving unit for raising and lowering the heating element unit and the heat insulating member together can be given.

According to the present invention, since the heating element unit is provided between the lid and the holder, the amount of heat radiated from the processing atmosphere in the reaction vessel to the outside is reduced. Can quickly stabilize in temperature,
Further, a wide processing region in which the temperature is stabilized can be secured. By adjusting the height of the heating element unit in accordance with the process, the function of keeping the processing atmosphere warm (the function of preheating the processing gas in the case of the film forming process) can be optimized in accordance with the process.

Another aspect of the present invention is a heating element unit provided between the lid and the holder and having a resistance heating element with a small amount of metallic impurities sealed in ceramics, and one end connected to the heating element unit. And a ceramic protective tube, which is located at the lower side of the lid through which the other end penetrates the lid, and is led out of the lid through a power supply path of the heating element unit, and a lower surface of the lid. A cylindrical body through which the protective tube is penetrated, a concave portion formed at a position of the protective tube below the cylindrical body, and a detachably engaged with the concave portion and the cylindrical member. A stopper member for preventing the protection tube from moving upward by engaging with the body.

The resistance heating element is made of, for example, a high-purity carbon material, and the ceramic in which the resistance heating element is sealed is, for example, quartz. Further, for example, the concave portion is formed in the circumferential direction of the protective tube, and the stopper member is a C-shaped ring body provided so as to engage with the concave portion. According to the present invention, since the stopper member is provided below the protection tube in the power supply path, the heating element unit is not sucked in even when the processing atmosphere is reduced in pressure.

According to another aspect of the present invention, a surface is provided between the lid and the holder so as to face the bottom of the holder, and a resistance heating element having a small amount of metallic impurities is sealed in the ceramic. A heating element unit, and a cover body detachably provided to the heating element unit and covering the heating element unit.

More specifically, a cover is provided so as to face the lower surface of the heating element unit, and the cover body is configured to cover the upper surface and the side peripheral surface of the heating element unit. It is preferable that the lower edge of the side peripheral surface of the cover is brought into contact with the planar portion so that the heating element unit is surrounded by the cover and the planar body. According to the present invention, there is an effect that the frequency of cleaning the heating element unit can be reduced.

[0016]

FIG. 1 is an overall configuration diagram showing an embodiment of a vertical heat treatment apparatus according to the present invention, and FIG. 2 is a schematic view of the vertical heat treatment apparatus. The outline of the apparatus will be briefly described with reference to these drawings. Reference numeral 2 in FIG. 1 denotes a reaction tube having a double tube structure including an inner tube 2a and an outer tube 2b made of, for example, quartz. A metal cylindrical manifold 3 is provided at a lower side of the reaction tube 2. ing.

The inner pipe 2a has an open upper end and is supported on the inner side of the manifold 3. The upper end of the outer tube 2 b is closed, and the lower end is hermetically joined to the upper end of the manifold 3. In this example, the inner pipe 2a, the outer pipe 2b
And the manifold 3 constitute a reaction vessel.
31 is a base plate.

In the reaction tube 2, a large number of, for example, 126
A plurality of wafers W to be processed are placed on a wafer boat 21 serving as a holder in a shelf shape in a horizontal state with a vertical interval therebetween. As shown in FIG. 2, the wafer boat 21 is provided with a plurality of columns 24 provided between a top plate 22 and a bottom plate 23, and the columns 24 are formed with grooves for holding the peripheral portion of the wafer W. The wafer boat 21 is held on a lid 32 via a region where the heat retaining unit 4 is installed. 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. When the lid 32 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 a role of closing the lower end opening of the reaction vessel composed of

Around the reaction tube 2, a heater 25, for example, composed of a resistance heater is provided 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 further provided outside the heater 25, thereby forming a heating furnace 20 (see FIG. 2).

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. FIG. 1 shows one of the gas supply pipes 34, which is connected to a gas supply source 35 via a valve V1, a flow meter MFC and a valve V2. An exhaust pipe 36 is connected to the manifold 3 so that air can be exhausted from a space between the inner pipe 2a and the outer pipe 2b, and the inside of the reaction tube can be maintained at a predetermined reduced pressure atmosphere by a vacuum pump 37. I have.

Next, the heat retaining unit 4 and its related parts will be described with reference to FIGS. The heat insulation unit 4 includes a heat insulating unit 40 made of ceramics, for example, made of quartz. The heat insulating unit 40 has a circular upper surface portion 41 and a circular bottom plate portion 42 (the bottom plate portion 42 in FIG. 5).
Are omitted), and three pillars 43 provided at intervals in the circumferential direction for connecting the upper surface portion 41 and the bottom plate portion 42 to each other. A large number of grooves 44 are formed in each of the three columns 43, and quartz fins 45 (not shown in FIG. 4) serving as heat insulating members are formed in the grooves 44 of the three columns 43. Are inserted and arranged in multiple stages. The quartz fins 45 are for suppressing the heat above this from being dissipated to the lid 32 side.

On the upper surface 41 of the heat insulating unit 40, a heat shield plate 46 (shown in FIG. 4) in which a black film layer such as a carbon layer or a silicon carbide layer is sealed in a quartz plate, for example. ), And a heating element unit 5 in the form of a sheet, for example, is provided on the upper side through a gap. The heating element unit 5 is formed by enclosing a resistance heating element having a small amount of metallic impurities in ceramics, for example, quartz, and in this example, as shown in FIG. Plate (quartz plate) 5
1, a heater wire 52 made of a high-purity carbon material is spirally arranged. Also, quartz may be interposed between the heater wires 52, 52 adjacent to each other, and in this case, the heater wire 52 is wired between the spiral partition walls made of quartz. The heating element unit 5 is preferably the same size as or larger than the wafer W in order to increase the heat retaining effect.

A rotating shaft for rotating the wafer boat 21 penetrates through the upper and lower portions 41 and 42 of the heat insulating unit 40, the quartz fin 45, the heat shield plate 46, and the center of the heat generating unit 5. Holes 41a, 42a, 45
a, 46a and 5a are formed respectively.

On the upper surface portion 41, for example, a cylindrical (ring-shaped) quartz cover body 53 having a hole 53a formed in the center and covering the heating element unit 5 and the heat shield plate 46.
Is mounted (removably provided). Therefore, the heating element unit 5 is placed in a space surrounded by the cover body 53 and the upper surface portion 41, and is isolated from the processing atmosphere, so that reaction products are less likely to adhere.

The quartz plate 51 of the heating element unit 5
A first protective tube 54 is connected to the lower surface side of the peripheral edge of the first protective tube 54, and the power supply line 55 is collected at a connection portion of the first protective tube 54 as shown in FIG. Has been inserted. Although not shown in detail in the figure, the power supply line 55 is sealed in a thin quartz tube, and the protection tube 5 is sealed.
4 inside. A second protective tube 47 is provided between the top surface portion 41 and the bottom surface portion 42 of the heat insulation unit 40, and both ends are opened to the top surface portion 41 and the bottom surface portion 42, respectively. The protection tube 54 is inserted into the second protection tube 47 and penetrates through the lid 32 of the reaction vessel.

Here, the lower part of the heat insulating unit 40 will be described with reference to FIG.
2 is mounted on a tray 62 provided at the upper end of an elevating rod 61 penetrating the lid 32 of the reaction vessel, and the elevating rod 61 can be raised and lowered by a driving unit 63 provided on the lid 32. Has become. The driving unit 63 is, for example, a ball
A combined screw mechanism or an air cylinder can be used. An interlocking plate 64 is provided on the elevating rod 61, and between the interlocking plate 64 and the lid 32, the elevating rod 61 is surrounded so as to ensure airtightness between the processing atmosphere and the outside. For example, metal tongue
The door 65 is provided.

The interlocking plate 64 is connected to the boat elevator 3
3 extends to the lower end of the first protective tube 54 so as not to interfere with the plane, and the lower end is fixed. Therefore, the heat insulation unit 40 and the heating element unit 5 can be moved up and down in conjunction with each other, and their height can be adjusted by the drive unit 63. A metal bellows 66 is also provided between the interlocking plate 64 and the lid 32 so as to surround the first protective tube 54. The height adjustment by the driving unit 63
For example, the control is performed based on a control signal from the control unit 60. For example, the control unit 60 may be configured to output a corresponding control signal by inputting a numerical value of the height, but the type of the process is designated. Thus, an appropriate height command (control signal) according to the process, which is grasped in advance, may be output.

In FIGS. 4 and 5, reference numeral 48 denotes a third protective tube provided between the upper surface portion 41 and the bottom surface portion 42 of the heat insulating unit 40. For example, a thermocouple 49, which is a temperature detecting unit for detecting a temperature near the heating element unit 5, is inserted. Thermocouple 4
Numeral 9 is enclosed in a quartz tube, for example, and is led out of the lid 32. This quartz tube is also configured to be able to move up and down by the interlocking plate 64 similarly to the first protective tube 54.

Returning to the description of the wafer boat 21, the wafer boat 21 passes under the cover body 53 and the central holes 53a, 46a, 41a, 45a and 42a of the heat insulating unit 4 and under the lid body 32. It is mounted on a rotating shaft 26 that penetrates to the side, and this rotating shaft is configured to be vertically separable, and can be rotated by a rotation drive unit M provided on the boat elevator 33. It has become.

Next, the operation of the above embodiment will be described. Here, as an example of specific processing, HTO (High
An example in which an oxide film called Temperature Oxide is formed by a CVD process will be described. For example, when a code corresponding to this processing is input to the control unit 60, a control signal corresponding to this code is output to the drive unit 63, and the heat insulation unit 40 and the heating unit 5 are set in advance according to the process. Adjusted to the height.

Then, a predetermined number of wafers W to be processed are held on the wafer boat 21 in a shelf shape, and the boat elevator 33 is lifted and carried into the reaction vessel. When the wafer boat 21 is carried in, the processing atmosphere of the reaction vessel is maintained at, for example, about 600 ° C.
Is carried in and the lower end opening of the reaction vessel (specifically, the lower end opening of the manifold 3) is closed by the lid 32. Then, the processing atmosphere is heated to about 800 ° C. by the heater 25, and the exhaust pipe 36 The pressure inside the reaction vessel is reduced to a predetermined degree of vacuum by the vacuum pump 37 through.

On the other hand, the heating element unit 5 is on standby at, for example, about 100 ° C., but starts to rise in temperature while the wafer boat 21 is being loaded, and the temperature of the heating element unit 5 is set to, for example, the temperature of the processing atmosphere during film formation. To a slightly higher temperature.
The time when the heating element unit 5 and the processing atmosphere reach the respective target temperatures is, for example, substantially the same timing. Here, the temperature of the heating element unit 5 is a temperature measured by placing a temperature sensor at a position several millimeters near the heating element unit 5.

Thereafter, the process stands by without performing the process for the time for stabilizing the temperature (recovery time), and thereafter, the two gas supply pipes 34 (only one is shown in FIG. 1 as described above). Dichlorosilane (SiH2 Cl2) gas and dinitrogen monoxide (N2 O) gas from a reaction vessel (reaction tube 1)
And the pressure in the reaction vessel is maintained at, for example, a predetermined degree of vacuum while being supplied into the manifold 3). At this time, the rotation shaft 26 is rotated to rotate the wafer boat 21.

Here, since the temperature near 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 slightly below the heating element unit 5 becomes higher than the temperature of the processing atmosphere near 800 ° C. ing. For this reason, the dichlorosilane gas and the nitrogen monoxide gas supplied to the lower side of the reaction vessel are decomposed when passing the heat retaining unit 4, and diffuse into the processing atmosphere in a state where the decomposition is advanced,
Active species are deposited on the wafer W to form a silicon oxide film. Thereafter, the power of the heater 25 is controlled to lower the temperature inside the reaction vessel, and the power supplied to the heating element unit 5 is reduced to zero to lower the temperature of the heating element unit 5. For example, when the temperature of the processing atmosphere reaches 600 ° C. To lower the wafer boat 21.

According to the above embodiment, the following effects can be obtained.

(1) Since the heating element unit 5 is provided between the wafer boat 21 and the lid 32, the amount of heat radiated from the processing atmosphere to the outside via the heat retaining unit 4 is reduced. Since the heat retaining unit 4 includes the heat generating unit 5, the heat retaining unit 4 has a good heat retaining property, and thus the heat capacity may be small. For this reason, after the temperature of the processing atmosphere reaches the target temperature, the time required for stabilizing the temperature (recovery time) can be shortened, and the throughput can be improved. In addition, since the variation in the recovery time for each batch process is reduced, the reproducibility of the process is improved.

(2) As described above, since the heat retaining effect of the heat retaining unit 4 is large, a region having high temperature uniformity extends to the lower side. Product wafers can be placed in the area where they have to be placed, and the number of processed wafers per batch can be increased. This also improves the throughput.

(3) 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 is reduced.
As a result, the uniformity of the concentration of the active species between the wafers W arranged in the wafer boat 21 and in the plane of each wafer W is increased, and the uniformity of the film thickness between the wafers W and in the plane of the wafer W is improved. Will be higher.

(4) Since the height of the heat retaining unit 4 can be adjusted, the temperature profile in the height direction on the lower side of the wafer boat 21 can be made suitable for the process (processing temperature, etc.). Further, in combination with the temperature control of the heating element unit 5, more detailed temperature control can be performed, and the temperature of the processing atmosphere can be more quickly stabilized at the target temperature, and the area with high temperature uniformity can be expanded. Can be. FIG. 7 shows a wafer boat 2
It is explanatory drawing which shows the mode which adjusted the relative height of the heating element unit with respect to 1 to h1 about a certain process, and adjusted to h2 about another process.

(5) Since the heating element unit 5 is covered with the cover body 53, contact with the gas descending from the wafer boat 21 side is prevented. In this example, the cover body 53 and the heat insulating unit 40 are connected to each other. Since the heating element unit 5 is placed in a space surrounded by the upper surface portion 41, the gas hardly flows to the lower surface of the heating element unit 5, and the heating element unit 5
Adhesion of reaction products to the surface is suppressed. Therefore, the cover body 5
Even if the cleaning of 3 is performed frequently, the frequency of cleaning the heating element unit 5 can be reduced, so that the burden of maintenance work is small.

In the above example, the height of the heat retaining unit 4 is adjusted in accordance with the process in the above-described example. However, when performing one process, after the wafer boat 21 is loaded into the reaction vessel, For example, during the heating, the heat retention unit 4
Is brought closer to the wafer boat 21 and thereafter the heat insulating unit 4
Height adjustment, such as lowering the height position of the camera. Further, the heat insulation unit 40 is provided without the driving unit 63.
A height adjusting member such as a quartz block may be interposed between the bottom surface portion 42 and the lid 32 to change the height of the height adjusting member according to the process. In this case, for example, a method of changing the number of steps of the quartz block or replacing the quartz block with a quartz block having a different height can be adopted.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. This embodiment differs from the previous embodiment in that the heat retaining unit 4 is fixed to the lid 32. A through-hole 32 a of a first protection tube 54 made of quartz extending from the heating element unit 5 is formed in the lid 32 of the reaction vessel, and the through-hole 32 is formed on the lower surface of the lid 32. Ring 7 so as to surround the
1 is attached. A first cylindrical body 72 is tightly attached to the inner peripheral portion of the fixing ring 71 from below, and the first protective tube 54 penetrates through the through-hole 32a, and further the first cylindrical body 72, and is drawn out downward. The lower part of the first cylindrical body 72 is configured as a large diameter part, and a pressing ring 73 is provided at the lower end so as to surround the first protective tube 54.

The lower inner end of the first cylindrical body 72 and the upper inner end of the pressing ring 73 are formed as an inclined surface facing upward and an inclined surface facing downward, respectively. In, a gap having a triangular cross section exists. A so-called O-ring 74, which is a sealing ring made of resin, is closely inserted into this gap. A screw portion 72a is formed on the outer peripheral surface of the large diameter portion of the first cylindrical body 72, and a second cylindrical body 75 is screwed to the screw portion 72a from below. The diameter of the second cylindrical body 75 is reduced so that the lower side of the second cylindrical body 75 is adapted to the diameter of the first protective tube 54. 75a presses the pressing ring 73 upward, and as a result, the pressing ring 73 presses the O-ring 74, and the O-ring 74 is crushed to ensure airtightness.

On the other hand, the first protective tube 54 is provided with a second cylindrical body 75.
Projecting lower than the
A concave portion (counterbore) 54a is formed in the circumferential direction, and a C-shaped ring 76 serving as a stopper member is fitted in the concave portion 54a. A screw portion 75b is formed on the outer peripheral surface of the small diameter portion of the second cylindrical body 75.
For example, a metal protector 77 is screwed into b from below. The protector 77 includes a quartz tube 56 extending from a lower end of the first protective tube 54 (this quartz tube 56 is also a first tube).
Of the protection tube 54), and has a role of preventing an operator from accidentally damaging the quartz tube 56. The power supply line 55 extending from the quartz tube 56 is connected to an external cable (not shown).

Here, the method of attaching the first protective tube 54 will be described. A projection 75c is formed on the outer peripheral surface of the second cylindrical body 75, for example, at a position facing the diametrical direction.
As shown in FIG. 11, the concave portions 8 engaging with these projections 75c
A cylindrical jig 8 having 1 is prepared. Then, the jig 8 is externally fitted to the second tubular body 75 and turned so that the concave portion 81 and the projection 75c are engaged with each other, so that the second tubular body 75 becomes the first tubular body 72. Tightened against. When the protector 77 is detached, for example, the power supply path 55 and the external cable
When the connection of the cable is made in the protector 77 and the connection portion is maintained, for example, when the protector 77 is turned, the second tubular body 75 also turns and the tightening may be loosened. The second cylindrical body 7
If the protector 77 is turned while the rotation of the motor 5 is stopped, such a situation does not occur.

FIG. 8 shows a thermocouple 10 serving as a temperature detector.
0 is shown. This thermocouple 100 is for detecting the temperature on the lower side of the heating element unit 5 and is a quartz tube 10.
1 is inserted. The quartz tube 101 passes through the lid 32 through the inside of the third protective tube 48, and the mounting structure of the quartz tube 101 is the same as the mounting structure of the first protective tube 54 shown in FIG. is there.

According to such a structure, even if the first protective tube 54 is sucked in by setting the inside of the reaction vessel to a reduced pressure atmosphere, the lower surface of the C-shaped ring 76 is engaged with the lower surface of the concave portion 54a, and Since the upper surface of the C-shaped ring 76 engages with the lower end surface of the second cylindrical body 75, the suction of the first protective tube 54 is prevented. Similarly, suction of the quartz tube 101 for the temperature detection unit is also prevented. At the time of maintenance, the first protection tube 54 and the quartz tube 101 can be pulled out by removing the C-shaped ring 76.

As for the connection between the power supply line 55 and the external cable, for example, as shown in FIG. 12, the power supply line 55 exposed from the quartz tube 56 is constituted by an electrode rod.
Using a connector 82 made of metal or ceramics, the leading end of the power supply line 55 is connected to the male (female) connector portion 82A, while the external cable 83 is connected to the female (male) connector portion 8.
It may be configured to connect to 2B.

Further, a method of cleaning quartz parts in the heat retaining unit 4 and the like will be described. FIG. 13 and FIG.
Reference numeral 4 denotes a jig 9 for cleaning the heating element unit 5 on behalf of quartz parts. The jig 9 is made of a material capable of withstanding a chemical solution as a cleaning solution, for example, a fluororesin, and includes a top plate 91 having a handle 91a and a bottom plate 9.
2 are connected by three support rods 93. The heating element unit 5 is inserted into the groove 94 of the support rod 93, and is supported upward while slightly floating from the bottom plate 92.
For example, it is fixed to the jig 9 by a lock mechanism 92a composed of a rotatable L-shaped member. Thus, the heating element unit 5
Of the heating element unit 5 by floating the
When the jig 9 is immersed in the cleaning liquid together with the jig 9, the cleaning liquid can contact the heating element unit 5. A cap 95 made of, for example, a fluororesin having chemical resistance is covered on the distal end of the first protection tube 54.
4, a seal ring 96 is interposed. The use of the cap 95 prevents the power supply path 55 from being corroded by contact with the cleaning liquid. The top plate 9
1, a notch 91b is formed and the periphery thereof is formed as a step. By supporting the flange 95a of the cap 95 at the step of the notch 91b, the own weight of the cap 95 is applied to the heating element unit 5. I try not to join.

In this example, the heating element unit 5 is taken as an example. However, when cleaning the thermocouple sealed in the quartz tube, the base end is covered with a similar cap to prevent corrosion of the thermocouple element wire. To do. Also, when the rotating shaft 26 of the wafer boat 21 is cleaned, the fitting portion is covered with a similar cap,
The dimensional accuracy is not disturbed by etching (due to cleaning).

In the above, the present invention is not limited to application to a low pressure CVD apparatus, but can also be applied to a so-called oxidation and diffusion furnace.

[0052]

According to the present invention, since the heating element unit is provided between the lid of the reaction vessel and the holder for the object to be processed, the time required for stabilizing the temperature can be shortened, and the heating element unit is further provided. Since the height of the heating element can be adjusted, there is an effect that the heating element unit can be placed at an appropriate position for the process.

[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 outline of the above-mentioned device.

FIG. 3 is a cross-sectional view showing a heat retaining unit including a heat generating unit and a heat insulating unit used in this embodiment, and means for elevating the heat retaining unit.

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 an explanatory diagram showing a cross section and a plane of a heating element unit.

FIG. 7 is an explanatory diagram showing a state in which the heights of the heat generating unit and the heat insulating unit are adjusted.

FIG. 8 is a vertical sectional side view showing a mounting structure of a heat retaining unit including a heat generating unit and a heat insulating unit to a lid used in another embodiment of the vertical heat treatment apparatus of the present invention.

FIG. 9 is a cross-sectional view illustrating a structure for attaching a protective tube to a lid used in the embodiment of FIG.

FIG. 10 is an exploded perspective view showing the mounting structure shown in FIG. 9 in an exploded manner.

FIG. 11 is a perspective view showing a jig used when attaching and detaching the protection tube.

FIG. 12 is a side view illustrating an example of a wiring of a power supply path of the heating element unit.

FIG. 13 is a side view showing a jig used when cleaning the heating element unit.

FIG. 14 is a perspective view showing the jig of FIG.

FIG. 15 is a vertical sectional side view showing a conventional vertical heat treatment apparatus.

[Explanation of symbols]

 2 Reaction Tube 21 Wafer Boat 26 Rotation Axis 3 Manifold 32 Lid 4 Heat Insulation Unit 40 Heat Insulation Unit 45 Quartz Fin 46 Heat Shield Plate 47 Second Protection Tube 5 Heating Element Unit 53 Cover Body 54 First Protection Tube 54a recess 60 control part 61 elevating rod 62 tray 63 drive part 64 interlocking plate 65, 66 bellows 72 first cylindrical body 74 O-ring 75 second cylindrical body 76 C-type ring 77 protector 8 jig 82 Connector 9 Cleaning jig 95 Cap

Continued on the front page (72) Inventor Choei 1-24-1 Machiya, Shiroyamacho, Tsukui-gun, Kanagawa Prefecture F-term (reference) 4K030 CA04 CA12 GA13 KA04 KA05 KA10 KA11 KA23 KA46 5F045 AA06 AA20 AB32 DP19 EB02 EK09 EM01 EM10

Claims (11)

[Claims] An object to be processed is held in a shelf shape on a holder supported on a lid, and the holder is loaded into the reaction vessel from below, and the lower end of the reaction vessel is held by the lid. In a vertical heat treatment apparatus for performing heat treatment on the object to be treated by heating the inside of the reaction vessel in a heating atmosphere, wherein the lid is independently provided between the lid and the holder. It is provided with a heating element unit that is supported and provided and encloses a resistance heating element with a small amount of metal impurities in ceramics, and the heating element unit is configured to be variable in height. Vertical heat treatment equipment. 2. The vertical heat treatment apparatus according to claim 1, wherein a heat insulating member supported by a lid is provided independently of the holder at a lower side of the heating element unit. 3. The vertical heat treatment apparatus according to claim 2, wherein the heat generating unit and the heat insulating member are configured so that their heights can be changed together. 4. The vertical heat treatment apparatus according to claim 3, further comprising an elevating mechanism for elevating and lowering the heat generating unit and the heat insulating member together. 5. A plurality of objects to be processed are held in a shelf shape by a holder supported on a lid, and the holder is loaded into the reaction vessel from below, and the lower end of the reaction vessel is held by the lid. In a vertical heat treatment apparatus that heat-treats the object to be processed by heating and decompressing the inside of the reaction vessel in a heated atmosphere and a reduced pressure atmosphere, wherein A heating element unit in which a heating element is sealed in ceramics, one end of which is connected to the heating element unit and the other end of the heating element unit is located below the lid body through the lid; A protective tube made of ceramics for leading out of the lid through a power supply path, a tubular body fixed to the lower surface of the lid and penetrating the protective tube, and a lower side of the tubular body in the protective tube A recess formed in a portion located at Vertical heat treatment apparatus being characterized in that and a stopper member for preventing upward movement of the protective tube by engage and the recess of the detachably engaging said tubular body. 6. The vertical heat treatment according to claim 5, wherein the concave portion is formed in a circumferential direction of the protective tube, and the stopper member is a C-shaped ring body provided so as to engage with the concave portion. apparatus. 7. A plurality of objects to be processed are held in a shelf shape by a holder supported on a lid, and the holder is loaded into the reaction vessel from below, and the lower end of the reaction vessel is held by the lid. In a vertical heat treatment apparatus in which the inside of the reaction vessel is heated and the heat treatment is performed on the object to be processed, between the lid and the holder, so as to face the bottom of the holder. A planar heating element unit in which a resistance heating element with a small amount of metallic impurities is sealed in ceramics; and a cover detachably provided to the heating element unit for covering the heating element unit. A vertical heat treatment apparatus comprising: a body. 8. A heating device, comprising a planar portion supported by a lid so as to face a lower surface of the heating element unit, wherein the cover body is configured to cover an upper surface and a side peripheral surface of the heating element unit. 8. The vertical type according to claim 7, wherein a lower edge of the side peripheral surface of the body is brought into contact with said planar portion so that the heating element unit is surrounded by the cover body and said planar body. Heat treatment equipment. 9. The vertical heat treatment apparatus according to claim 1, wherein the resistance heating element is made of a high-purity carbon material. 10. The vertical heat treatment apparatus according to claim 1, wherein the ceramic in which the resistance heating element is sealed is quartz. 11. A heat-insulating member is provided below the heating element unit.
The vertical heat treatment apparatus according to any one of 7, 8, 9 and 10.