JP2010239142A - Heat treatment apparatus, and heat treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform treatment with high uniformity in a plane and between substrates when heat treatment, such as film deposition, to the substrates in a reaction tube is performed by reducing pressure and then supplying treatment gas into the vertical reaction tube having an upper end surface curved outward. <P>SOLUTION: Structures such as a plurality of plates are provided in the upper region of a treatment region in which a substrate in a reaction tube is held, and thereby, a space on an upper side of a containment region of a substrate holder is filled. A treatment gas introduction duct is provided in the vertical direction along an outer peripheral surface of the reaction tube, and treatment gas is raised in the duct so as to be introduced in a treatment space through a gas inlet on an upper end surface of the reaction tube. By arranging the structures, retention of the treatment gas in the upper region is reduced, and generation of an excessive reaction active species is suppressed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat treatment apparatus and a heat treatment method for performing a heat treatment of a substrate such as a semiconductor wafer by supplying a processing gas after depressurizing the inside of a reaction tube.

  Among semiconductor manufacturing equipment, there are batch-type heat treatment equipment such as vertical furnaces and horizontal furnaces. Among them, the vertical heat treatment equipment (vertical furnace) is a vertical reaction of a wafer boat holding a large number of substrates. It is an apparatus that carries it into a tube and performs heat treatment. As an example of the heat treatment performed by this type of heat treatment apparatus, there is a film formation process by a CVD process under reduced pressure.

  Such a heat treatment apparatus 100 will be described with reference to FIG. The heat treatment apparatus 100 decompresses the reaction tube 101 in which a large number of substrates 110 are held, supplies a film forming process gas into the reaction tube 101, and heats the substrate 110 with a heater 102. In this apparatus, a gas is reacted on the substrate 110 to form a film. The processing gas is introduced from the side surface or the upper side of the reaction tube 101 and exhausted from the lower side of the reaction tube 101.

Since the inside of this single tube type reaction tube 101 is depressurized, in order to prevent implosion (crushing inward due to a pressure difference between the inside and outside of the reaction tube 101), the opposite side of the open end faces outward. It has a dome shape that curves. Since the substrate 110 cannot be installed in the curved portion, a wide space 103 surrounded by a curved surface is formed in the reaction tube 101 above the processing region where the substrate 110 is processed.
When heat treatment is performed in such a reaction tube 101, the heat of the substrate 110 is radiated to the upper end side of the reaction tube 101 through the space 103, and the temperature near the center of the substrate 110 is lowered. Above the tube 101, the in-plane temperature variation becomes large, and the in-plane film thickness becomes non-uniform.

  In addition, in the place (upper side) close to the space 103, the temperature is lower than that on the lower side, and therefore, temperature variation between the substrates 110 occurs. Therefore, the heater 102 is adjusted to create a temperature gradient in the reaction tube 101. However, among recent processes, for example, when forming a silicon nitride film (SiN film), there is a process that requires eliminating or making the temperature gradient between the substrates 110 as small as possible. While making the temperature in the tube 101 uniform, it is required to perform heat treatment so as to obtain a uniform film thickness within the surface and between the substrates 110.

  Patent Document 1 describes a technique in which a heat insulating material is provided on an upper part of a boat that holds a substrate to suppress rapid heating of the top plate of the boat. Therefore, it takes a long time for the temperature to stabilize when it is loaded next time, resulting in a decrease in throughput. In addition, the boat stroke length must be increased by the length of the heat insulating material, which increases the size of the apparatus. Furthermore, due to the temperature rise and fall of the heat insulating material, the reactive species adhering to the heat insulating material may be peeled off from the heat insulating material due to the difference in thermal expansion and contraction rate from the heat insulating material, resulting in particles. There is a risk of damage.

JP-A-2004-111715 ((0030), FIG. 1)

  The present invention has been made under such circumstances, and an object of the present invention is to uniformly perform heat treatment in a plane and between substrates in a heat treatment apparatus that supplies a processing gas after reducing the pressure in the reaction tube and performs heat treatment. It is an object of the present invention to provide a heat treatment apparatus and a heat treatment method that can perform the same.

The heat treatment apparatus of the present invention
A substrate holder holding a large number of substrates in parallel is carried into a reaction tube whose tip surface is curved outward from an opening on one end side, and after reducing the pressure in the reaction tube, a processing gas is supplied and heated in a heated atmosphere. In a heat treatment apparatus for performing a hot film treatment on the substrate in
A gas supply port formed on a front end surface and / or a side surface of the reaction tube in order to supply a processing gas to a processing region in which the substrate is held in the reaction tube;
Evacuation means for evacuating the inside of the reaction tube from below;
Heating means provided to surround the reaction tube;
It is provided in a space between the front end surface of the reaction tube and the storage area of the substrate holder, and has a structure for filling the space. In this case, filling the space does not only mean that the space is completely closed, but filling a part of the space as described in the best mode for carrying out the invention described later. It also means that.

The heat treatment may be a film forming process. In that case, the processing gas is a processing gas containing a silane-based gas or a processing gas containing a silane-based gas and an ammonia gas, and the film forming process forms a polycrystalline silicon film or a silicon nitride film. A treatment is preferred.
The heat treatment may be oxidation treatment or impurity diffusion treatment.
The heat treatment is preferably performed by heating so that the temperature of the product substrate held by the substrate holder is uniform between the substrates. In this case, “equalizing the temperature between the substrates” means that the temperature variation between the substrates is within 1 to 2% of the set temperature.

The structure is preferably a plate-like body provided so as to intersect with the axis of the reaction tube so that a gap is formed between the structure and the side wall of the reaction tube. Or it is preferable that the said structure is a plate-shaped body provided crossing the axis | shaft of the reaction tube and in which the hole part was formed.
It is preferable that the structure body further includes a plurality of plate-like bodies stacked in the axial direction of the reaction tube.
The gas supply ports may be arranged at intervals on the side wall of the reaction tube along the length direction of the reaction tube.

The heat treatment method of the present invention comprises:
A substrate holder holding a large number of substrates in parallel is carried into a reaction tube whose tip surface is curved outward from an opening on one end side, and after reducing the pressure in the reaction tube, a processing gas is supplied and heated in a heated atmosphere. In the heat treatment method of performing a heat treatment on the substrate in
Carrying in the substrate holder holding a number of the substrates in the reaction tube;
Evacuating the reaction tube from below;
Supplying a processing gas from the front end surface or / and the side surface into the reaction tube;
Heating the substrate and performing a film forming process,
A structure for filling the space is provided in a space between the distal end surface of the reaction tube and a storage area for the substrate holder. Even in this case, filling the space also means filling a part of the space.
The step of supplying the processing gas may be a step of supplying from the gas supply ports arranged at intervals on the side wall of the reaction tube along the length direction of the reaction tube.
.

  In the present invention, since the structure for reducing the volume of this region and suppressing the retention of the processing gas is provided between the front end surface of the reaction tube and the storage region of the substrate holder, the retention of the processing gas By suppressing this, excessive reaction of a processing gas such as a film forming gas can be suppressed, and heat treatment can be performed so as to obtain a uniform film thickness in the plane and between the substrates. In addition, since the reactive active species generated in this region are deposited on the structure and the amount of excessive reactive active species flowing to the processing region where the substrate is held is reduced, further in-plane and between the substrates. A film can be formed to have a uniform film thickness. In addition to the case where a film forming process gas is used as the process gas, the structure acts as a heat insulating material not only in the case where an oxidation or impurity diffusion process gas is used, but the region above the process region from the substrate. Since the heat transfer to is suppressed, the in-plane temperature difference is reduced in the upper region of the reaction tube, and the heat treatment can be performed uniformly.

[First Embodiment]
1st Embodiment of the heat processing apparatus 1 of this invention is described with reference to FIGS. The heat treatment apparatus 1 shown in FIG. 1 includes a cylindrical body 21 made of, for example, a heat insulating material, and a heater 22 that is a heating means provided in the circumferential direction along the inner wall surface of the cylindrical body 21. . As the heater 22, for example, a carbon wire heater sealed in ceramics is used. The heater 22 is divided into a plurality of regions in the vertical direction, and is configured so that the temperature of each region can be individually controlled.

  Inside the cylindrical body 21, a reaction tube 3 made of, for example, quartz and having a substantially cylindrical shape and a perfectly circular horizontal cross section is provided, and one end side (lower end side) thereof opens as a furnace port. In order to prevent implosion of the reaction tube 3, the tip surface (upper end side) is curved outward in a dome shape. A flange 42 is formed at the periphery of the opening 41 of the reaction tube 3, and the opening 41 is opened and closed by a lid 43 that can be raised and lowered by a boat elevator (not shown).

  On the lid 43, a wafer boat 45, which is a substrate holder for holding a plurality of, for example, 125 wafers W in a shelf shape, is provided. The region where the wafers W are held constitutes the processing region 10. ing. The distance between the wafer W held on the wafer boat 45 and the inner wall of the reaction tube 3 is configured to be as narrow as possible so that the flow rate of the processing gas is increased and the heat treatment is uniformly performed in the plane. For example, it is 10 mm on one side. A heat insulating unit 46 storing a large number of plate-like bodies 46 a and a rotating shaft 44 are provided below the wafer boat 45. The rotating shaft 44 is attached to a boat elevator (not shown) via a lid 43. It is configured to be rotated by a motor M that is a drive unit. Accordingly, the wafer boat 45 is configured to be carried in and out of the reaction tube 3 by raising and lowering the lid body 43 and rotating together with the rotary shaft 44 by the rotation of the motor M.

As shown in FIG. 2, a gas supply duct 60, which has a flat, vertically long box-like body, reacts on the outer wall of the reaction tube 3 as a gas supply path for supplying gas into the reaction tube 3. It is provided along the outer surface of the side wall of the tube 3.
A gas discharge hole 61 communicating with the inside of the reaction tube 3 is formed in a region corresponding to the processing region 10 of the gas supply duct 60, and this gas discharge hole 61 is processed throughout the processing region 10 in the reaction tube 3. In order to supply gas, a plurality of, for example, ten locations are formed at substantially constant intervals in the vertical direction. In this example, the gas discharge holes 61 are vertically arranged in one row, but a plurality of rows, for example, two rows may be arranged.

  For example, seven gas flow paths 73 are formed in the circumferential direction in the flange 42, and the distal end side of each gas flow path 73 opens into the gas supply duct 60 at the base portion of the flange 42. For example, seven gas supply pipes 65 are connected to the base end side of each gas flow path 73, and these gas supply pipes 65 are connected to different gas supply sources, for example. For example, one of the gas supply pipes 65 is connected to, for example, a SiH2Cl2 (dichlorosilane) gas source 72A via a valve 70A and a flow rate adjusting unit 71A, and for example, the other one is connected to a valve 70B and a flow rate adjusting unit 71B. For example, it is connected to an NH3 (ammonia) gas source 72B. The SiH2Cl2 (dichlorosilane) gas source 72A and the NH3 gas source 72B constitute a gas source 72.

  As shown in FIGS. 3 and 4, the upper space 11 above the processing region 10 (region between the front end surface of the reaction tube 3 and the storage region of the wafer boat 45) includes a plurality of, for example, five sheets. The fins 33 made of, for example, quartz fixed by, for example, three support shafts 32 are provided so that the circular plates 31 are stacked with a predetermined gap of, for example, 13 mm. The fins 33 are used to fill the upper space 11, and are, for example, discs made of quartz, for example, having an outer diameter slightly smaller than the inner diameter of the reaction tube 3 and having three notches 23 formed on the outer edge, for example. It is mounted on a support plate 34 having a shape. On the inner wall of the reaction tube 3, holding claws 35 are welded at three locations so as to correspond to the size and spacing of the notches 23 of the support plate 34, and the support plate 34 is below the holding claws 35. From above, the fins 33 are raised above the holding claws 35 so that the notches 23 overlap the positions of the holding claws 35, and the cutouts 23 are rotated so as not to overlap the positions of the protrusions of the holding claws 35. Thus, it is configured to be held on the holding claw 35. When the support plate 34 and the fins 33 are installed, for example, the support plate 34 and the fins 33 are placed on the wafer boat 45 described above, and are carried into the reaction tube 3 together with the wafer boat 45 and rotated. You may make it install by doing. In this example, as described above, the holding claw 35, the support plate 34, and the fins 33 are configured to be separable, but these may be welded. In that case, for example, the lower surface of the position corresponding to the upper space 11 of the reaction tube 3 is cut, the holding claws 35, the support plates 34 and the fins 33 are welded to the reaction tube 3, and then the upper portion of the reaction tube 3 is again attached. You may make it weld. At this time, for example, spot welding is performed so that the upper space 11 is not completely sealed so that the support plate 34 does not become a substantially upper surface of the reaction tube 3. The fins 33 and the support plate 34 correspond to the structures in the claims. This structure is not particularly limited to the fins 33 as long as the structure fills the upper space 11 (reduces the volume of the upper space 11). good.

  An exhaust port 5 for exhausting the atmosphere in the reaction tube 3 is formed on the side surface on the opening 41 side, which is one end side of the reaction tube 3 in FIG. A vacuum exhaust means 51 such as a vacuum pump capable of reducing the pressure in the reaction tube 3 is connected to the exhaust port 5 via an exhaust pipe 53 having a pressure adjusting unit 52 formed of, for example, a butterfly valve.

Next, an example of a heat treatment method using the heat treatment apparatus 1 described above will be described in the case where a SiN film is formed on the surface of a silicon wafer (hereinafter referred to as “wafer W”) by a CVD method.
First, for example, the 125 wafer boat 45 is held with wafers W and is loaded into the reaction tube 3 using a boat elevator (not shown). Thereafter, the lid 43 is raised, the reaction tube 3 is sealed, the inside of the reaction tube 3 is decompressed to, for example, 27 Pa (0.2 Torr) by the vacuum exhaust means 51, and the reaction tube 3 is set in advance by the heater 22. The temperature is raised to, for example, 760 ° C. This process temperature is controlled so that the wafer W in the reaction tube 3 has a constant temperature (within 1 to 2% of the set temperature, that is, 760 ° C. ± 5 ° C.).

  At this time, the above-described fin 33 is composed of a large number of discs 31 and has a smaller heat capacity as compared with the case where a solid cylinder having the same diameter as the disc 31 is provided, for example. The temperature of the wafer W is hardly hindered, and the inside of the reaction tube 3 is heated in substantially the same temperature increase time as when the fins 33 are not provided. Incidentally, several wafers on the upper side of the wafer W, for example, about five are not product wafers W but dummy wafers. The dummy wafer functions as a heat insulating material that suppresses a decrease in yield in a processing atmosphere, for example, an unstable region of the processing temperature, and suppresses heat radiation from the product wafer W.

  Next, the valves 70A and 70B are opened, and SiH2Cl2 gas and NH3 gas, which are processing gases, are introduced from the gas sources 72A and 72B into the gas supply duct 60 through the gas supply pipe 65 and the gas flow path 73, respectively. . The processing gas rises while being heated in the gas supply duct 60 and flows into the reaction tube 3 from the gas discharge hole 61, and a narrow gap between the wafer W and the inner wall of the reaction tube 3 is directed downward. The silicon nitride film (SiN film) is generated on the surface of the wafer W by diffusing toward the center of the wafer W from the gap.

  Further, the processing gas flows into the upper space 11 through a gap between the support plate 34 and the inner wall of the reaction tube 3. Since the upper space 11 is provided with fins 33 and has a small volume, Since the flow velocity does not decrease so much in the space 11 and flows to the processing region 10, the generation of excess reactive species is suppressed. As described above, the fin 33 is provided with a large number of disks 31 and has a large surface area, so that the reactive species generated in the upper space 11 are adsorbed on the surface of the fin 33. As a result, it is consumed and the flow rate is increased. For this reason, the amount of reactive species introduced into the processing region 10 is greatly reduced as compared with the case where the upper space 11 is hollowed out.

Further, since the fins 33 and the support plate 34 also serve as heat insulators, heat radiated from the wafers W held on the upper side of the wafer boat 45 to the upper space 11 can be suppressed. The temperature difference in the plane of the wafer W becomes smaller.
Then, the gas containing unreacted processing gas and by-products is exhausted from the exhaust port 5 at the bottom of the reaction tube 3 by the vacuum exhaust means 51. The above-described processing gas is diluted with, for example, N2 gas, but a related description is omitted for convenience.

  According to the above embodiment, since the fins 33 are provided in the upper space 11 that is an area where the wafer W is not held, the retention of the processing gas in the upper space 11 is suppressed, and the reactive species are consumed. The Therefore, as described above, it is possible to form a film with high uniformity within the surface of the wafer W and between the wafers W while suppressing the film increase on the peripheral edge of the wafer W and the upper wafer W. it can.

Further, even in the case of forming a SiN film, for example, in a process that requires the temperature of the wafer W in the reaction tube 3 to be constant, the temperature of the wafer W is kept constant and the uniformity between the wafers W is high. A film forming process can be performed. Even when the set temperature of the heater 22 is adjusted according to the concentration of the processing gas in the reaction tube 3 to create a temperature gradient in the reaction tube 3, the retention of the processing gas in the upper space 11 is suppressed. Since the reactive species are consumed, the same effect as described above can be obtained.
Since the fin 33 and the support plate 34 function as heat insulating materials, the temperature difference in the surface of the upper wafer W is reduced. For example, the number of dummy wafers is reduced to about 3, for example, and the number of product wafers W is reduced. It can increase and productivity can be improved.

  In addition, since the fins 33 are installed not in the upper part of the wafer boat 45 but in the reaction tube 3, there are problems such as a decrease in throughput and an increase in the stroke length of the wafer boat 45 as described above. Absent. Further, since the fin 33 is not subjected to a rapid temperature change, the possibility of damage due to heat shock is reduced, and due to the difference in thermal expansion and contraction rate between the reactive active species (SiN film) adhering to the surface and the fin 33. Since the separation of the reactive species is suppressed, the generation of particles is reduced.

  In the above example, the five circular plates 31 are provided on the fin 33. However, for example, the number of the circular plates 31 may be about ten or more, or the fin 33 may not be provided as shown in the embodiments described later. good. Further, although the reduced pressure atmosphere is used when supplying the processing gas, it may be an atmospheric pressure. In this case, before starting the heat treatment, in order to exhaust the atmosphere in the reaction tube 3 (discharge gas that does not contribute to the heat treatment), the processing gas is introduced after the pressure in the reaction tube 3 is reduced.

  In the above example, the case where the SiN film is formed using the heat treatment apparatus 1 has been described. However, not only such a CVD method but also an oxygen gas is supplied as a processing gas to form an oxide film on the surface. Such oxidation treatment may be used. Even in this case, the fin 33 functions as a heat insulating material, and the temperature in the surface of the upper wafer W is kept uniform, and as a result, productivity is improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, since the configuration other than the above-described support plate 34 and fins 33 is the same as that of the first embodiment, description thereof will be omitted.
In this embodiment, in the upper space 11, as a structure, a substantially conical support plate 34a, a fin 33a provided so as to close the inside of the support plate 34a, and a small diameter stored inside the fin 33a. Fins 36a are provided.

The small-diameter fin 36a is composed of a plurality of, for example, three disks 37a having the same diameter, and a support shaft 38a penetrating the center of the disk 37a.
The fins 33a on the outer side of the fins 36a are ring-shaped, such as a plurality of discs 31a whose outer diameter gradually increases from the upper side, for example, three discs 31a and the discs 31a so that the discs 31a are concentric. And a cylindrical support shaft 32a provided to connect the inner diameter sides. The support shaft 32a is composed of a plurality of low-height cylindrical bodies so that the outer diameter side can be connected slightly to the inner diameter end of the disk 31a. The fins 33a are configured by alternately laminating and welding 31a.

The above-mentioned fin 36a is stored in the support shaft 32a of the fin 33a, and the upper surface of the disc 37a and the inner surface of the support shaft 32a are arranged so that the disc 31a is at the same height as the disc 37a of the fin 36a. Each is provided with a fitting claw (not shown), and is configured such that the fin 36a is held by the support shaft 32a by inserting the fin 36a into the support shaft 32a and rotating the fin 36a.
A holding claw 35a is formed at the upper end of the outer peripheral surface of the support shaft 32a of the fin 33a.

The support plate 34a has a substantially conical shape having a hollow inside and a lower surface opened, and an upper surface portion thereof is opened so that the support shaft 32a of the fin 33a can pass therethrough. In addition, a notch 23a corresponding to the holding claw 35a of the support shaft 32a described above is formed in the opening, and the support shaft 32a of the fin 33a is inserted into the opening from below, so that the fin 33a The fins 33a can be suspended from the support plate 34a by the holding claws 35a.
In FIG. 5, the notch of the support plate 34 a and the holding claw 35 in the reaction tube 3 are omitted, but the support plate 34 a is supported on the holding claw 35 as in the first embodiment described above. The plate 34a is configured to be held. The following embodiments are similarly omitted.
Even with such a configuration, the same effects as those of the first embodiment described above can be obtained.
Moreover, as shown in FIG. 7, the fin 36a does not need to be provided, and as shown in FIG. 8, the disk 31a of the fin 36a may be enlarged to the extent that it is close to the inner wall of the support plate 34a. .

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIGS. This embodiment also has the same configuration as that of the first embodiment except for the support plate 34 and the fins 33 described above.
In the upper space 11, as a structure, a ring-shaped support plate 34b, a substantially ring-shaped fin 33b provided on the upper surface of the support plate 34b, and a small-diameter fin 36b stored inside the fin 33b are provided. ing.

The small-diameter fin 36b is composed of a plurality of, for example, five disks 37b and a support shaft 38b that passes through the center of the disk 37b. The fins 33b outside the fins 36b include a plurality of ring-shaped, for example, five disks 31b, and a support shaft 32b for fixing the upper and lower disks 31b at the outer edge of the disk 31b. The above-described fin 36b is housed in the opening at the center of the disc 31b, and the disc 31b is configured to have the same height as the disc 37b of the fin 36b. The uppermost disc 31b is formed to have a slightly smaller diameter than the other discs 31b in order to match the shape of the upper end surface in the reaction tube 3, and the support shaft 32b is adjusted accordingly. Is also provided on the inside at the top. The support plate 34b and the fin 33b are welded and fixed by the lowermost support shaft 32b of the fin 33b.
Even with such a configuration, the same effects as those of the first embodiment described above can be obtained.
The fin 36b and the fin 33b are configured to be held together by a fitting claw, a notch, a holding claw, etc., as in the second embodiment described above, but are omitted here. . The same applies to the following examples.

  Further, as shown in FIG. 11, the fin 36b may not be provided, and as shown in FIG. 12, the fin 33b is not provided and the inner diameter of the support plate 34b is narrowed above the support plate 34b. A ring-shaped member 39b may be provided. As shown in FIG. 13, a support plate 34c having a disc shape and a plurality of openings 40c formed on the periphery thereof may be used.

[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIGS. A heat treatment apparatus 2 shown in FIG. 14 includes a reaction tube 4 different from the heat treatment apparatus 1 described above. As shown in FIG. 15, the reaction tube 4 is provided with a gas supply duct 62 extending to the top of the reaction tube 4 so as to supply the processing gas from the upper end of the reaction tube 4. A gas discharge hole 63 having a diameter larger than that of the gas discharge hole 61 described above is opened at the upper end of the reaction tube 4.

In the reaction tube 4, the processing gas is supplied to the processing region 10 through the upper space 11. Even in such a configuration, a film forming process is performed in the same manner as the heat treatment apparatus 1 described above, and by providing a structure having a configuration similar to that of the first to third embodiments, The same effect can be obtained. That is, the present invention can be applied to a heat treatment apparatus having a configuration in which the processing gas flows downward or laterally through the reaction tube and the processing gas may stay in the upper space 11 or may absorb heat. it can. Therefore, for example, a plurality of openings are formed on the side surface of the reaction tube 3 so as to face the gas discharge hole 61 in the first embodiment described above, and the processing gas is exhausted from the openings. Anyway.
A gas discharge hole 61 similar to that of the above-described reaction tube 3 may be further formed on the side surface of the reaction tube 4.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described with reference to FIGS. The heat treatment apparatus 7 shown in FIG. 16 has substantially the same configuration as the heat treatment apparatus 1 described above, but as shown in FIG. 17, the reaction tube 6 is disposed above the gas discharge hole 61 formed in the reaction tube 6. A pressure equalizing hole 66 having a diameter larger than that of the gas discharge hole 61 is formed so as to communicate with the inner upper space 11. The pressure equalizing hole 66 increases the flow rate of the processing gas in the gas supply duct 60 to increase the pressure (flow rate) of the processing gas supplied from the gas discharge holes 61 to the processing region 10 in the reaction tube 6. ). That is, most of the processing gas is supplied to the upper space 11 from the pressure equalizing hole 66 and then descends in the reaction tube 6 and is exhausted.

  As shown in FIG. 18, the support plate 34a shown in FIG. 5 is held on the holding claws 35 on the upper portion of the reaction tube 6. The support plate 34a is supported on the support plate 34a. In order to narrow the central opening, the ring-shaped member 39b shown in FIG. 12 described above is provided, and the support plate 34a and the member 39b form a structure in the claims.

In this heat treatment apparatus 7 as well, the SiN film or the like is formed in the same manner as the heat treatment apparatus 1 described above. However, as described above, most of the processing gas is from the pressure equalizing hole 66 to the upper space 11. And discharged from the reaction tube 6. At this time, the support plate 34a and the member 39b provide the same effects as described above.
Hereinafter, other structural examples of the structure installed in the upper space 11 in the heat treatment apparatus 7 will be described. Not only these structures but also the structures described up to the first to third embodiments are described. Even if it provides, the same effect is acquired.

FIG. 19 shows an example in which a ring-shaped member 39c having an enlarged opening diameter at the center of the member 39b shown in FIG. 18 is used. FIG. 20 shows an example in which a ring-shaped member 39d in which a large number of small-diameter openings 24 are formed at the center of the member 39b is used. FIG. 21 shows a support plate 34d in which the opening on the upper end surface of the support plate 34a shown in FIG. 5 is closed and a small-diameter opening 25 is formed on the entire surface. FIG. 22 shows a substantially disk-shaped support plate 34e provided with, for example, two base portions 26 so as to suppress the retention of the processing gas at a position above the position of the holding claws 35. FIG. 23 shows an example using only the support plate 34b shown in FIG. FIG. 24 shows an example in which a member 39c is combined with the central opening of the support plate 34b. FIG. 25 shows an example in which the member 39d is combined with the support plate 34b. FIG. 26 shows a flat support plate 34f in which a large number of small-diameter openings 27 are formed.
Even when the structure shown above is used, the same effect as described above can be obtained.

  Experiments conducted to confirm the effects of the present invention will be described below. In the experiment, a heat treatment apparatus 1 was used to perform a SiN film deposition test using 110 wafers W for each example under the following process conditions. Further, in the upper space 11, experiments were performed by providing the above-described structures as in the following examples. After film formation, the film thickness was measured at a plurality of points on each wafer W, and the film thickness uniformity and film formation speed were calculated. In addition, since the upper five wafers among the 110 wafers W used dummy wafers, the measurement for these dummy wafers was not performed. In addition, when the structure is provided in the upper space 11, the temperature may be absorbed by the structure and a temperature gradient may be formed. In each example, the output of the heater 22 was adjusted so that each wafer W had a constant temperature.

(Process conditions)
Processing temperature: 760 ° C
Process gas: dichlorosilane gas / ammonia gas = 150/1500 sccm
Processing pressure: 27 Pa (0.2 Torr)
(Experimental example 1)
In the upper space 11, the fins 33 and the support plate 34 in the first embodiment are provided as structures.
(Experimental example 2)
The fin 33 of Experimental Example 1 was not provided.
(Comparative example)
The experiment was conducted without providing any structure in the upper space 11.
(Experimental result)
As shown in FIG. 27, it can be seen that by providing the support plate 34 and the fins 33 as structures in the upper space 11, the deposition rate on the upper side can be suppressed and the deposition rate can be uniform between the wafers W. It was. This is presumably because the retention of the processing gas in the upper space 11 was suppressed as described above, and excessive reactive species were consumed in the upper space 11. Further, by providing the fins 33 in addition to the support plate 34 in addition to the support plate 34, the uniformity of the film forming speed between the wafers W is improved. Therefore, the surface area and volume of the structure provided in the upper space 11 are improved. It is considered that the above effect increases as the value increases.

  Since the film formation speed varies depending on the processing temperature, the difference in film formation speed between the experimental example 1 and the comparative example on the upper side of the processing region 10 was calculated assuming that this difference was caused only by the temperature difference. The temperature difference was found to be about 4-5 ° C. However, as described above, since the temperature in the reaction tube 3 is measured before the experiment and the output of the heater 22 is adjusted, such a temperature difference does not occur. As described above, it is considered to be due to the retention of the processing gas and the influence of excess reactive species.

  Further, the uniformity of the film thickness within the surface of the wafer W is improved, and in particular, the uniformity of the wafer W on the upper side is improved. This result also shows that the effect increases as the volume of the structure in the upper space 11 increases. As described above, this is an effect as a heat insulating material of the structure, and heat dissipation from the central portion of the wafer W is suppressed, and in the upper wafer W, the temperature difference between the central portion and the peripheral portion is 1 ° C. It was found that the temperature decreased to about 0.5 ° C. or less.

It is a longitudinal section showing the whole heat treatment equipment composition concerning a 1st embodiment of the present invention. It is a perspective view which shows an example of the reaction tube in said heat processing apparatus. It is a perspective view which shows the structure provided in said reaction tube. It is sectional drawing of the reaction tube which shows the said structure. It is a disassembled perspective view which shows the structure based on the 2nd Embodiment of this invention. It is sectional drawing of the reaction tube which shows the said structure. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is a disassembled perspective view which shows the structure based on the 3rd Embodiment of this invention. It is sectional drawing which shows the said structure. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is a longitudinal cross-sectional view which shows the whole structure of the heat processing apparatus which concerns on the 4th Embodiment of this invention. It is a perspective view which shows an example of the reaction tube in said heat processing apparatus. It is a longitudinal cross-sectional view which shows the whole structure of the heat processing apparatus which concerns on the 5th Embodiment of this invention. It is a perspective view which shows an example of the reaction tube in said heat processing apparatus. It is sectional drawing which shows the structure provided in said reaction tube. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is sectional drawing which shows the other example of the said structure. It is a characteristic view which shows the experimental result in the Example of this invention. It is a longitudinal cross-sectional view showing the conventional heat processing apparatus.

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 3 Reaction tube 5 Exhaust port 10 Processing area | region 11 Upper space 22 Heater 23 Notch 33 Fin 34 Support plate 35 Holding claw 45 Wafer boat 51 Vacuum exhaust means 60 Gas supply duct 61 Gas discharge hole

Claims (2)

A substrate holder holding a large number of substrates in parallel is carried into a reaction tube whose tip surface is curved outward from an opening on one end side, and after reducing the pressure in the reaction tube, a processing gas is supplied and heated in a heated atmosphere. In the heat treatment apparatus for performing heat treatment on the substrate in
A gas supply port formed in a front end surface of the reaction tube in order to supply a processing gas to a processing region in which the substrate is held in the reaction tube;
Evacuation means for evacuating the inside of the reaction tube from below;
Heating means provided to surround the reaction tube;
A heat treatment apparatus, comprising: a structure provided in a space between a front end surface of the reaction tube and a storage area for a substrate holder, and filling the space. A substrate holder holding a large number of substrates in parallel is carried into a reaction tube whose tip surface is curved outward from an opening on one end side, and after reducing the pressure in the reaction tube, a processing gas is supplied and heated in a heated atmosphere. In the heat treatment method of performing a heat treatment on the substrate in
Carrying in the substrate holder holding a number of the substrates in the reaction tube;
Evacuating the reaction tube from below;
Supplying a processing gas from the tip surface into the reaction tube;
Heating the substrate and performing a heat treatment,
A heat treatment method characterized in that a structure for filling the space is provided in a space between the front end surface of the reaction tube and a storage area for the substrate holder.

Images