JPH0855811A - Vertical furnace - Google Patents

Abstract

PURPOSE:To provide a vertical furnace whose interior can be efficiently cooled while the reduction of the heat insulation and generation of mottles are prevented. CONSTITUTION:A vertical furnace has a reaction tube 3 for housing substrates 5 to be treated and tubular heater 1 disposed around the tube 3 with a gap. The heater heats the substrates 5 put in the tube 3 to treat them. A lower layer heat insulated plate 18 having a hole 20 and upper layer heat insulated plate 19 having a groove 21 continuing to the side face from a position corresponding to the hole 20 are laminated to form a top plate 17 which closes the upper end opening of the heater 1, thereby forming a heat radiating passage with the hole 20 and groove 21 at the top end of the heater 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical furnace in a semiconductor manufacturing apparatus, and more particularly to a vertical furnace capable of rapidly lowering the temperature inside the furnace.

[0002]

2. Description of the Related Art In semiconductor manufacturing, a substrate such as glass is processed while being heated. For example, in a CVD apparatus for forming a thin film on a glass substrate, the substrate is housed in a vertical reaction furnace and heated while supplying a reaction gas,
A thin film is vapor-deposited on a substrate.

As shown in FIG. 5, a conventional vertical furnace has a cylindrical heater 1 having a heating element, a soaking tube 2 housed in the heater 1 with a gap, and a soaking tube 2 inside. The reaction tube 3 accommodated with a gap is provided, and the boat 6 that holds the substrate 5 to be processed in the reaction tube 3. The boat 6 can load the substrates 5 in multiple stages in a horizontal state with a gap, and holds a plurality of substrates 5 in the reaction tube 3 in this state. The boat 6 is placed on an elevator (not shown) via a boat cap 7, and can be moved up and down by this elevator. Therefore, the loading of the substrate 5 into the reaction tube 3 and the removal from the reaction tube 3 are performed by the operation of the elevator.

The heater 1 has an opening at its upper end closed by a heat insulating plate 8, and a groove 9 is formed in the heat insulating plate 8 as shown in FIG. Therefore, the groove 9 forms a passage that connects the inside and the outside of the heater 1, and the radiator 12 and the cooling fan 13 are connected to this passage through the heat radiating pipe 11 having the damper 10 that can be opened and closed. ing.

To form a thin film on the substrate 5 charged in the reaction tube 3, the heating element of the heater 1 is heated to heat the reaction tube 3 through the soaking tube 2, and the reaction gas is introduced into the reaction tube 3. At the same time, the reaction tube 3 is evacuated to form a thin film on the surface of the substrate 5. And the substrate 5 on which the film is formed
The heating of the heater 1 is stopped, the damper 10 is opened, and the cooling fan 13 is operated to release the heated air in the heater 1 to the outside through the passage including the groove 9 and the radiator 12, By lowering the temperature in the reaction tube 3 to a predetermined temperature, the elevator is operated to pull out the boat 6 from the reaction tube 3.

[0006]

In the above-mentioned conventional vertical furnace, as shown in FIG. 6, the passage for radiating heat in the heater 1 is a groove 9 formed by simply cutting out the heat insulating plate 8. Since the heat insulating plate 8 was formed, the heat insulating plate 8 was thinner in the groove 9 portion than in other portions, and the heat insulating property in the ceiling portion of the heater 1 was partially deteriorated. Therefore, the heating efficiency in the furnace by the heater 1 may be lowered, the throughput in the heat treatment of the substrate may be lowered, or the heat insulating state in the furnace may be uneven to make it difficult to realize a uniform heating temperature. It was

Further, as shown in FIG. 5, since the passage for heat dissipation, which is formed by the groove 9, is opened at the corner of the upper end portion of the heater 1, the heated air in the heater 1 is uniformly distributed by the cooling fan 13. Not being sucked out, the cooling efficiency in the furnace is lowered and the throughput in the substrate processing is lowered, and also the heat-treated substrate may be adversely affected due to the uneven temperature in the furnace. It should be noted that if a passage for heat dissipation is opened in the central portion of the upper end of the heater 1, the problem at the time of cooling can be solved, but in this case,
Since the groove 9 is formed to extend in the heat insulating plate 8 for a long time, a new problem arises that the above-mentioned deterioration of the heat insulating property and the unevenness become more remarkable.

The present invention has been made in view of the above-mentioned conventional circumstances, and it is an object of the present invention to provide a vertical furnace capable of efficiently cooling the inside of the furnace while preventing deterioration of the heat insulating property of the furnace and generation of spots. To aim.

[0009]

In order to achieve the above object, the vertical furnace of the present invention comprises a reaction tube for accommodating a substrate to be processed, and a cylindrical heater provided around the reaction tube with a gap. In a vertical furnace of a semiconductor manufacturing apparatus that heats and processes a substrate accommodated in a reaction tube by a heater, a lower layer side heat insulating plate in which a through hole is formed and a position from a position corresponding to the through hole to a side surface are continuous. The upper opening of the heater is closed by a top plate formed by stacking an upper heat insulating plate on which a groove is formed,
It is characterized in that a passage for radiating heat, which is composed of the through hole and the groove, is formed at the upper end of the heater.

[0010]

According to the vertical furnace of the present invention, the heater has its upper end opening closed by the top plate in which the lower layer side heat insulating plate and the upper layer side heat insulating plate are laminated, and the heated air in the heater is lower side. The heat is discharged from the through hole of the heat insulating plate to the outside of the furnace through the groove of the upper heat insulating plate. Further, in the vertical furnace of the present invention, since the lower heat insulating plate covers the groove that causes the lowering of the heat insulating property of the ceiling part of the heater, the whole top plate forming the ceiling part of the heater is partially covered. A decrease in heat insulation is prevented. In this way, since the influence of the groove on the heat insulation is prevented, it is possible to extend the groove relatively long and set the position of the through hole of the lower layer side heat insulating plate to the center of the ceiling part, and to heat the inside of the heater. The air can be exhausted uniformly to cool the inside of the furnace uniformly and efficiently.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vertical furnace according to an embodiment of the present invention will be described with reference to the drawings. The same parts as those of the above-mentioned conventional example will be described with the same reference numerals in the drawings. As shown in FIG. 1, the vertical reactor of this embodiment includes a cylindrical heater 1 having a heating element 1a, a cylindrical heat equalizing tube 2 housed in the heater 1 with a gap, and a heat equalizing tube. The reaction tube 3 has a cylindrical reaction tube 3 accommodated therein with a gap, and a boat 6 for holding a substrate 5 to be processed in the reaction tube 3. The reaction tube 3 defines a reaction chamber that accommodates the substrate 5. The reaction tube 3 is connected to a gas introduction tube 15, and the gas introduction tube 15 is connected to a reaction gas supply source (not shown). An exhaust pipe 16 is connected to the lower end of the reaction tube 3 to exhaust the reaction chamber.

The upper end of the heater 1 is closed by a top plate 17. The top plate 17 has a structure in which a lower heat insulating plate 18 and an upper heat insulating plate 19 are superposed as shown in FIG. Has become. A circular through hole 20 is formed in the lower heat insulating plate 18 provided in contact with the upper end of the heater, and the through hole 20 is located at the center of the lower heat insulating plate 18 (that is, the heater 1
It is located on the central axis of. In addition, the lower heat insulating plate 18
Grooves 21 are formed in the upper heat insulating plate 19 which is provided on the upper side of the heat insulating plate 19. The groove 21 is continuous from the center position of the heat insulating plate 19 corresponding to the through hole 20 to the side surface, and heat is insulated at the end of the groove 21. The side surface of the plate 19 is cut away.

Therefore, when the lower layer side heat insulating plate 18 and the upper layer side heat insulating plate 19 are superposed, the through hole 20 and the groove 21 communicate with each other, and as a result, the through hole 20 and the groove 21 cause the top plate 17 to be connected. A passage that connects the inside and the outside of the heater 1 is formed. A radiator 12 and a cooling fan 13 are connected to this passage through a heat radiating pipe 11 having a damper 10 that can be opened and closed, and the heated air in the heater 1 is discharged through this passage.

Further, as shown in FIG. 3, a plurality of grooves 2 are formed in an annular base 23 supporting the heater 1 on the base 22.
4 is formed by cutting out, and when the lower end of the heater 1 is fitted in the base 22, the heater 1 is formed by the groove 24.
A passage that connects the inside and the outside of the is formed.

The thin film is formed on the substrate 6 charged in the reaction tube 4 by heating the heating element 1a of the heater 1 to heat the reaction tube 3 through the soaking tube 2 and supplying the reaction gas, as in the conventional case. Tube 1
While introducing the reaction gas into the reaction tube 3 via 5,
The reaction tube 4 is evacuated through the exhaust pipe 16 to form a thin film on the surface of the substrate 5. When heating by the heater 1, the ceiling plate 17 that closes the upper end opening of the heater 1 has a structure in which the lower layer side heat insulating plate 18 covers the groove 21, so that the through hole 20 is set on the central axis of the heater 1. Even if the groove 21 is extended relatively long, the top plate 1
As a whole, a partial decrease in heat insulating property is prevented, and the heater 1 uniformly and efficiently heats the inside of the furnace.

When the above film forming process is completed, the exhaust pipe 16
The heating by the heater 1 is stopped while the exhaust from the chamber is continued, and the heated atmosphere in the reaction tube 3 is discharged to the outside, thereby lowering the temperature in the reaction tube 3. At the same time, the damper 10 is opened and the cooling fan 13 is opened.
The air from the outside of the furnace is introduced from the intake passage formed by the groove 24 and flows upward from the lower end through the gap between the heater 1 and the heat equalizing tube 2, and the heated air in the heater 1 is passed through. The heat is released to the outside via the radiator 12 including the holes 20 and the grooves 21 and the radiator 12 to lower the temperature in the heater 1 as well, which also lowers the temperature in the reaction tube 3.

After the temperature inside the reaction tube 3 is lowered to a predetermined temperature, the elevator is operated to pull out the boat 6 from the reaction tube 3 and take out the film-formed substrate 5 from the reaction tube 3. Since the through hole 20 is located on the central axis of the heater 1 during the cooling by the exhaust air from the above through hole 20, the heated air in the heater 1 will be in this through hole 20.
Since the gas is uniformly exhausted from the inside, the inside of the furnace is cooled uniformly and efficiently. Therefore, the temperature of the reaction tube 3 rapidly decreases,
The temperature of the substrate 5 rapidly drops to a predetermined temperature that can be taken out of the reaction furnace.

FIG. 4 shows a vertical furnace according to another embodiment of the present invention. The same parts as those in the above-described embodiment are designated by the same reference numerals, and the duplicated description will be omitted. In this example,
The present invention is applied to a vertical furnace provided with a soaking tube 32 having an open upper end instead of the soaking tube 2 having an upper end closed.
The soaking tube 32 is provided such that its upper end is in contact with the lower surface of the lower layer side heat insulating plate 18, and the heated air inside the soaking tube 32 is discharged from the hole 20 to the outside of the furnace. In addition, as in the above-described embodiment, an intake passage for introducing air from outside the furnace is provided at the lower end of the soaking tube 32, and the through hole 2
In accordance with the exhaust from 0, the soaking pipe 32 from this intake passage
A relatively low temperature air is introduced from the outside of the furnace.

Therefore, in this embodiment, in addition to the same effects as the above-described embodiments, a space close to the substrate 5 which is the target of temperature reduction (that is, the reaction tube 3 and the soaking tube 2).
Since the heated air can be released from the (gap between the substrate) and the substrate 5, the substrate 5 can be cooled more efficiently.

In each of the above-mentioned embodiments, the vertical furnace provided with the soaking tube 2 is shown. However, the present invention may be applied to a vertical furnace having no soaking tube, as in each of the above-mentioned embodiments. It is possible to obtain various effects. Further, although the cylindrical heater 1 is shown in each of the above-described embodiments, the present invention is not limited to this, and can be applied to tubular heaters having various sectional shapes. Further, the shapes of the lower layer side heat insulating plate 18 and the upper layer side heat insulating plate 19 are also
The shape is not limited to the disk shape as in the above-described embodiment, but may be variously set according to the cross-sectional shape of the heater so as to close the upper end opening of the heater 1.

A plurality of through holes 20 may be formed in the lower heat insulating plate 18, and the through holes 20 may have a shape other than a circular shape. Furthermore, the through hole 20 does not necessarily have to be provided in the center of the lower heat insulating plate 18, and for example,
A plurality of through holes may be arranged annularly or radially with the same center as the lower layer side heat insulating plate 18. It should be noted that if a through hole is formed at a target position with respect to the central axis of the heater 1 like the center of the lower layer side heat insulating plate 18, uniform cooling inside the heater can be realized. Even if the through-hole 20 is provided at a corner position deviated from the center, the laminated structure of the lower-layer side heat insulating plate 18 and the upper-layer side heat insulating plate 19 can prevent an adverse effect due to a partial decrease in heat insulating property. It is also possible to provide the through hole 20 at a position displaced from the center of the lower heat insulating plate 18.

Further, the groove 2 formed in the upper heat insulating plate 19
Since 1 may be communicated with the through hole 20, it may be variously changed depending on the number and position of the through holes 20, and the number to be formed is not limited to one, and a plurality may be formed depending on the situation. it can. Further, a passage for introducing air from the outside of the furnace into the heater 1 at the time of cooling, such as an intake passage formed by the groove 24 of the base 23, can be formed in various ways. It suffices that there is a passage in which air can be introduced from the outside in accordance with the exhaust air from any form.

[0023]

As described above, according to the vertical furnace of the present invention, the heater is provided by the top plate formed by stacking the lower layer side heat insulating plate having the through holes and the upper layer side heat insulating plate having the grooves. Since the upper end opening was closed and a passage for heat dissipation consisting of a through hole and a groove was formed at the upper end of the heater, partial lowering of the heat insulating property of the entire top plate forming the ceiling part of the heater was prevented, and the inside of the furnace was prevented. In addition to being able to heat uniformly and efficiently, it is possible to extend the groove relatively long and set the position of the through hole of the lower layer side heat insulating plate at the center of the ceiling part of the heater. The air can be exhausted uniformly to cool the inside of the furnace uniformly and efficiently. Therefore, the processing efficiency of the substrate by the vertical furnace is improved, and the throughput is improved. Further, since the top plate of the heater has a laminated structure of the lower heat insulating plate and the upper heat insulating plate, a passage for heat dissipation can be easily formed in the ceiling portion of the heater, and a vertical furnace having the above effect can be obtained. It can be easily realized at low cost.

[Brief description of drawings]

FIG. 1 is a sectional view showing a vertical furnace according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a top plate according to an embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a heater supporting portion according to an embodiment of the present invention.

FIG. 4 is a sectional view showing a vertical furnace according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a conventional vertical furnace.

FIG. 6 is a perspective view showing a conventional top plate.

[Explanation of symbols]

 1 Heater 3 Reaction Tube 5 Substrate 17 Top Plate 18 Lower Layer Thermal Insulation Plate 19 Upper Layer Thermal Insulation Plate 20 Through Hole 21 Groove

Claims (1)

[Claims] 1. A semiconductor having a reaction tube for accommodating a substrate to be processed, and a cylindrical heater provided around the reaction tube with a gap, wherein the heater heats the substrate accommodated in the reaction tube for processing. In the vertical furnace of the manufacturing apparatus, the lower layer side heat insulating plate in which the through hole is formed and the upper layer side heat insulating plate in which continuous grooves are formed from the position corresponding to the through hole to the side surface are overlapped by the top plate. A vertical furnace characterized in that the upper end opening of the heater is closed, and a passage for radiating heat, which is composed of the through hole and the groove, is formed at the upper end of the heater.