JPH1197360A - Vertical heat treatment equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the weight and cost of a heat insulating structure, and to improve the thermal responsiveness by reducing the heat capacity. SOLUTION: A heat insulating structure 22 includes a substrate support 21 which supports a large number of substrates W at predetermined intervals in a vertical direction on an upper portion of a lid 20 which opens and closes a furnace port 2 at a lower portion of a vertical heat treatment furnace 3. In the vertical heat treatment apparatus, wherein the heat treatment is performed on the target substrate W in a soaking region in a furnace, the heat insulating structure 22 is provided.
Are a plurality of columns 32, and a plurality of reflective heat shield plates 33 provided on the columns 32 at predetermined intervals in the vertical direction.
It is composed of

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 In the manufacture of semiconductor devices, various heat treatment apparatuses are used to perform processes such as oxidation, diffusion, CVD, and annealing on a semiconductor wafer as a substrate to be processed. As one of such heat treatment apparatuses, a heat insulating structure includes a substrate support that supports a large number of substrates to be processed at predetermined intervals in a vertical direction on an upper portion of a lid that opens and closes a lower furnace port of a vertical heat treatment furnace. 2. Description of the Related Art There is known a vertical heat treatment apparatus in which a heat treatment is performed on an object to be processed in a soaking region in a furnace.

[0003] In this vertical heat treatment apparatus, how to prevent heat from escaping from the furnace port and its surroundings is an important issue in order to achieve uniform heat treatment in the furnace. In order to improve the heat insulation effect of the furnace port, there has been proposed a vertical heat treatment apparatus in which the heat insulation structure is formed of a heat shield plate made of opaque quartz for preventing the transmission of heat rays (Japanese Patent Laid-Open No. 6-208954). Gazette). Specifically, the heat insulating structure is composed of a plurality of columns and a plurality of opaque quartz heat shield plates provided on the columns at predetermined intervals in the vertical direction. The heat shield plate employs a configuration in which the surface of an opaque quartz substrate is covered with a transparent quartz layer as a measure for preventing etching.

[0004]

However, in the above vertical heat treatment apparatus, the heat shield plate is made of an opaque quartz substrate.
Since it is composed of the transparent quartz layers laminated on both sides, the thickness of one heat shield plate is increased to, for example, 3 to 4 mm. Further, in order to obtain a sufficient heat shielding effect, a large number of the above heat shielding plates, for example, about 10 to 20 sheets are required. For this reason, the weight and cost of the heat insulating structure have to be increased. In addition, since the heat capacity of the heat insulating structure is increased and the thermal response is poor, there is a limit in improving the throughput by rapid temperature rise and rapid temperature decrease.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can reduce the weight and cost of the heat insulating structure, improve the heat responsiveness by reducing the heat capacity, and increase the temperature by rapidly increasing and decreasing the temperature. It is an object of the present invention to provide a vertical heat treatment apparatus capable of improving throughput.

[0006]

Means for Solving the Problems To achieve the above object, a vertical heat treatment apparatus according to claim 1 of the present invention comprises a large number of sheets on an upper part of a lid for opening and closing a furnace port at a lower part of the vertical heat treatment furnace. In a vertical heat treatment apparatus, a substrate support supporting the substrates to be processed at predetermined intervals in a vertical direction is placed via a heat insulating structure, and the object to be processed is heat-treated in a soaking region in a furnace. It is characterized in that the body is composed of a support and a plurality of reflective heat shield plates provided on the support at predetermined intervals in the vertical direction.

A vertical heat treatment apparatus according to a second aspect is characterized in that the heat shield plate is formed of a reflective film and a transparent quartz layer covering the surface of the reflective film.

A vertical heat treatment apparatus according to a third aspect is characterized in that a cylindrical heat shield having reflectivity is provided on the inner peripheral surface or the outer peripheral surface of the furnace port.

A vertical heat treatment apparatus according to a fourth aspect is characterized in that a reflective cover material is provided on the upper surface of the lid.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing a vertical heat treatment apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view showing a heat insulation structure of the vertical heat treatment apparatus, and FIG. 3 is a heat shield plate constituting the heat insulation structure. FIG. 4 is an exploded perspective view showing the structure of the heat shield plate.

In FIG. 1, reference numeral 1 denotes a vertical heat treatment apparatus configured to be suitable for performing a film forming process on a substrate to be processed, for example, a semiconductor wafer W by, for example, low pressure CVD. The vertical heat treatment apparatus 1 includes a vertical heat treatment furnace 3 having a furnace port 2 at a lower portion. This vertical heat treatment furnace 3 is made of a material having heat resistance and corrosion resistance, for example, transparent quartz, and has a vertically long cylindrical reaction tube 4 whose upper end is closed and whose lower end is opened.
And a gas supply pipe part 5 and an exhaust pipe part 6 which are connected to the lower opening end of the reaction tube 4 and which are made of a material having heat resistance and corrosion resistance, for example, stainless steel, and which supply and exhaust processing gas and the like. And a cylindrical manifold 7.

The manifold 7 is attached to a lower portion of a horizontally provided base plate 8 by an attachment member 9. The base plate 8 has an opening 10 through which the reaction tube 4 passes. The upper and lower open ends of the manifold 7 and the lower open end of the reaction tube 4 are formed in outward flange shapes. The lower opening end of the reaction tube 4 is placed on the upper opening end of the manifold 7 via a sealing means, for example, an O-ring 11, and is airtightly connected by a connecting member 12.

A cylindrical inner tube 14 made of, for example, transparent quartz is attached to an inward flange portion 13 provided inside the manifold 7 in an upright state, and the inner tube 14 and the outer tube are reaction tubes. The reaction tube 4 preferably has a double tube structure with the tube 4. The gas supply pipe section 5
Is provided so as to supply a processing gas or the like upward along the inside of the inner pipe 14, and the exhaust pipe section 6 is provided with the inner pipe 1.
The exhaust gas after the treatment is exhausted from an annular passage 15 between the reaction tube 4 and the reaction tube 4.

The gas supply pipe section 5 is connected to a gas supply pipe leading to a supply source of a processing gas or the like, and the exhaust pipe section 6 is connected to a gas supply pipe.
An exhaust pipe leading to the exhaust system is connected. The exhaust pipe is provided with a decompression control device having a vacuum pump or the like capable of depressurizing and exhausting the inside of the reaction tube 4 from a predetermined depressurized atmosphere or a degree of vacuum, for example, from about atmospheric pressure to about 10 ^-8 Torr (illustrated). Omitted).

A heater 16 is arranged around the reaction tube 4 to heat the inside of the reaction tube 4 to a predetermined temperature, for example, 500 to 1200 ° C. This heater 16
A heater wire (heating resistance wire) 17 is formed in a coil shape or the like, the outside of the heater wire 17 is covered with a heat insulating material 18, and the outside of the heat insulating material 18 is further covered with an outer shell 1 such as a cooling jacket.
It has a structure covered with 9. The heater 16 is provided on the base plate 8.

A lid 2 for opening and closing a lower opening end of the manifold 7 forming the furnace port 2 is provided below the vertical heat treatment furnace 3.
0 is provided. The lid 20 is formed of a material having heat resistance and corrosion resistance, for example, stainless steel. Above the lid 20, a wafer boat 21 which is a substrate support that supports a large number of, for example, about 150, semiconductor wafers W at predetermined intervals in a vertical direction may be referred to as a heat insulating structure (also referred to as a heat shielding structure). The heat insulating structure 22 allows the furnace port 2 to be thermally insulated, and allows the semiconductor wafer W to be positioned in the soaking area in the furnace and to be heat-treated.

The lid 20 is attached to an elevating arm 24 of an elevating mechanism 23 so that the lid 20 can be opened and closed, and the wafer boat 21 can be carried in and out of the reaction tube 4. Has become. A sealing means, such as an O-ring 25, is provided on the upper peripheral portion of the lid 20 for sealing the furnace port 2 when the lid 20 is brought into contact with the lower opening end of the manifold 7 and the furnace port 2 is closed.

A heat insulating structure 22 is provided above the lid 20.
It is preferable that a receiving base 26 on which the heat-insulating structure is to be mounted is formed with an edge 27 for engaging the heat insulating structure and restricting the horizontal movement thereof. Also,
It is preferable that the pedestal 27 is configured to be rotated by a rotation driving means in order to uniformly heat-treat the semiconductor wafer W.

The wafer boat 21 includes upper and lower end plates 2.
A plurality of vertical frames 30 arranged so as to surround the circumference of the disk-shaped semiconductor wafer W are bridged between 8, 29, and a large number of, for example, about 150 semiconductor wafers W are placed on the vertical frames 30 in a horizontal state. There is provided a groove-shaped locking portion 31 that is supported in multiple stages at predetermined intervals in the vertical direction (height direction). Vertical frame 3 above
0 denotes a wafer W from a horizontal direction by a transfer mechanism (not shown).
Are open so that one can be transferred. The transfer mechanism has a transfer arm in the form of a thin plate fork. The semiconductor wafer W is mounted on the transfer arm and the transfer operation to the wafer boat 21 and the like is performed by loading the lower part of the vertical heat treatment furnace 3. This is done in the area.

On the other hand, as shown in FIG. 2, the heat insulating structure 22 includes a plurality of, for example, three
2, a plurality of, for example, three to
Five reflective heat shields (may be referred to as reflectors)
33 mainly. The support column 32 is erected on a circular bottom plate 34 mounted on the receiving table 26, and an upper plate 35 for mounting the wafer boat 21 is horizontally mounted on the upper end of the support column 32. Is provided. The upper plate 35 is provided with a circular opening 37 for fitting and positioning a circular projection 36 projecting from the bottom of the lower end plate 29 of the wafer boat 21. The above support 3
2. It is preferable that the bottom plate 34 and the upper plate 35 are formed of a material having heat resistance and corrosion resistance, for example, transparent quartz.

The heat shield plate 33 is used to prevent etching.
As shown in FIG. 3 and FIG. 4, in order to prevent metal contamination of the semiconductor wafer W by the reflective film, as shown in FIGS. 3 and 4, the reflective film 38 and transparent quartz layers 39 and 40 covering the surface of the reflective film 38 are formed. Is preferred. As one method of forming the heat shield plate 33, a pair of circular transparent quartz plates 41 and 42 forming the transparent quartz layers 39 and 40 are used, and a reflection film is formed on one surface of one of the transparent quartz plates 41. 38,
There is a method in which the reflection film 38 is sandwiched between another transparent quartz plate 42 and the peripheral portions of the two transparent quartz plates 41 and 42 are welded to be sealed and integrated.

As another method of forming the heat shield plate 33, a reflective film 38 is provided on the upper surface of a circular transparent quartz plate 41 on which one transparent quartz layer 39 is formed, and transparent quartz is coated on the reflective film 38. There is a method of casting and sealing the reflective film 38 to form the other transparent quartz layer 42 (not shown). The reflection film 38 can be provided as an extremely thin film by coating, CVD, vapor deposition, or the like. The transparent quartz layers 39 and 40 provided on both surfaces of the reflection film 38 may have a thickness of, for example, about 0.5 mm that can prevent etching.
Can be formed as thin as about 1 mm.

A plurality of the heat shield plates 33 are provided on the column 32 between the bottom plate 34 and the upper plate 35 in a horizontal state at predetermined intervals in the vertical direction. As one method of providing the heat shield plate 33 on the support 32, a hole (not shown) for passing the support 32 through the heat shield 33 is provided.
There is a method of fixing the heat shield plate to the column by welding the column and the column 32 after passing the column 32 through the hole. As another method of providing the heat shield plate 33 on the column 32,
There is a method in which the support 32 is divided into a plurality of parts so as to be used as spacers, and the heat shield plates 33 are stacked and provided via the divided support 32. In any method, the heat insulating structure 22 in which the plurality of heat shield plates 33 are provided on the support 32 can be easily manufactured.

In order to shield the heat around the furnace port 2, for example, an inner circumferential surface of the manifold 7, which is an inner circumferential surface of the furnace port 2,
It is preferable that a cylindrical heat shield 43 having reflectivity is provided. This heat shield 43 is preferably formed in a structure in which a reflection film is sandwiched between the two transparent quartz layers, similarly to the heat shield plate 33. Instead of providing the heat shield 43 on the inner peripheral surface of the furnace port 2, the heat shield 43 may be provided on the outer peripheral surface of the furnace port 2, that is, on the outer peripheral surface of the manifold 7. It is preferable that the heat shield 43 be removable from the inner peripheral surface of the manifold 7 and facilitate cleaning.

Further, in order to further enhance the heat shielding effect at the furnace port 2, it is preferable that a reflective cover member 44 is provided on the upper surface of the lid 20. This cover member 44 is preferably formed in a structure in which a reflective film is sandwiched between both transparent quartz layers, similarly to the heat shield plate 33. It is preferable that the cover member 44 can be removed from the upper surface of the lid 20 and is easy to clean.

The vertical heat treatment apparatus 1 configured as described above
First, the lid 20 is moved down to the loading area below the vertical heat treatment furnace 3 by the lifting mechanism 23,
The semiconductor wafer W is transferred to the wafer boat 21 placed on the lid 20 via the heat insulating structure 22 by the transfer mechanism. Next, the lid 20 is moved up to carry the wafer boat 21 and the heat insulating structure 22 into the furnace, and the lid 20 is brought into contact with the lower opening end of the manifold 7 to seal the furnace port 2. As a result, the position of the wafer boat 21 is set in the soaking area in the furnace by the heat insulating structure 22.

Next, the inside of the furnace is vacuum-replaced by depressurized exhaust from the exhaust pipe section 6, and the inside of the furnace is replaced by nitrogen gas by introducing an inert gas such as nitrogen (N ₂ ) gas from the gas supply pipe section 5. After that, when the semiconductor wafer W is rapidly heated to a predetermined processing temperature by the heater 16, the inside of the furnace is maintained at a predetermined reduced pressure state while introducing a predetermined processing gas from the gas supply pipe section 5 to form a film. Heat treatment such as treatment is performed. When the heat treatment is completed, the temperature of the semiconductor wafer W may be rapidly lowered to, for example, room temperature, and the semiconductor wafer W after the heat treatment may be carried out of the furnace together with the wafer boat 21 by the downward movement of the lid 20.

According to the vertical heat treatment apparatus 1, a wafer boat supporting a large number of semiconductor wafers W at predetermined intervals in the vertical direction on an upper part of a lid 20 for opening and closing a furnace port 2 at a lower part of a vertical heat treatment furnace 3. In a vertical heat treatment apparatus for mounting the semiconductor wafer W through the heat insulating structure 22 and heat-treating the semiconductor wafer W in the soaking area in the furnace, the heat insulating structure 22 includes a plurality of columns 3.
2 and a plurality of reflective heat shield plates 33 provided at predetermined intervals on the columns 32 in the vertical direction. Accordingly, the heat rays that escape from the furnace port 2 of the vertical heat treatment furnace 3 to the outside of the furnace are reflected toward the inside of the furnace by a plurality of stages of heat shield plates 33 constituting the heat insulating structure 22 and are shielded. Compared to a heat shield plate made of opaque quartz, the number of heat shield plates 33 can be reduced to enhance the heat shield effect.

The heat insulating structure of the conventional vertical heat treatment apparatus is 10
While up to 20 heat shields are required, 3 to 5 heat shields 33 suffice for this embodiment. Therefore, the weight and cost of the heat insulating structure 22 can be reduced, the thermal response can be improved by reducing the heat capacity, and the throughput can be improved by rapid temperature rise and rapid temperature decrease. Further, the diameter of the heat shield plate 33 is adjusted to the inner pipe 14 of the vertical heat treatment furnace 3.
Can be increased to the maximum allowable, so that the heat insulation can be improved.

In particular, since the heat shield plate 33 is formed of the reflective film 38 and the transparent quartz layers 39 and 40 covering the surface of the reflective film, metal contamination of the semiconductor wafer W by the metallic reflective film 38 is performed. Of course, the thickness of the heat shield plate 33 can be reduced. Since the conventional heat shield plate is composed of an opaque quartz substrate and a transparent quartz layer laminated on both sides thereof, the thickness of one heat shield plate is as thick as 3 to 4 mm, for example. In the form of 1
mm. Therefore, the weight and cost of the heat insulating structure 22 can be further reduced, and
The responsiveness can be further improved by reducing the heat capacity.

Further, on the inner peripheral surface of the manifold 7,
Since the cylindrical heat shield 43 having reflectivity is provided, the escape of heat rays from around the furnace port is prevented, so that the heat shield can be further improved. In addition, since the inner peripheral surface of the manifold 7 is covered with the heat shield 43, corrosion of the inner peripheral surface of the manifold due to contact of corrosive processing gas can be prevented. Further, since the cover member 44 having reflectivity is provided on the upper surface of the lid 20, the heat shielding property of the furnace port 2 can be further improved, and the lid by contact of corrosive processing gas can be achieved. Corrosion of the upper surface of the body can be prevented.

The present invention is not limited to the above embodiment, and various design changes and the like can be made within the scope of the present invention. For example, the vertical heat treatment furnace in the above embodiment includes a manifold, but the vertical heat treatment furnace in the present invention does not necessarily need to include a manifold. The vertical heat treatment apparatus to which the present invention is applied may be one that performs heat treatment such as oxidation, diffusion, and annealing in addition to CVD. Further, as the substrate to be processed, for example, an LCD substrate or the like can be applied other than the semiconductor wafer.

[0033]

In summary, according to the present invention, the following excellent effects can be obtained.

(1) According to the vertical heat treatment apparatus of the first aspect, a large number of substrates to be processed are supported at predetermined intervals in the vertical direction on the upper portion of the lid that opens and closes the lower furnace port of the vertical heat treatment furnace. In a vertical heat treatment apparatus in which a substrate support is placed via a heat insulating structure and the object to be processed is heat-treated in a soaking region in a furnace,
Since the heat insulating structure is composed of a plurality of columns and a plurality of reflective heat shield plates provided at predetermined intervals in the columns in the vertical direction, the number of heat shield plates is reduced. The heat shielding effect can be enhanced, the weight and cost of the heat insulating structure can be reduced, the thermal response can be improved by reducing the heat capacity, and the throughput can be improved by rapid temperature rise and rapid temperature decrease.

(2) According to the vertical heat treatment apparatus of the second aspect, since the heat shield plate is formed of the reflective film and the transparent quartz layer covering the surface of the reflective film, the heat shield plate is covered by the reflective film. Of course, it is possible to prevent metal contamination of the processing substrate,
Since the thickness of the heat shield plate can be reduced, the weight and cost of the heat insulating structure can be further reduced, and the responsiveness can be further improved due to the decrease in heat capacity.

(3) According to the vertical heat treatment apparatus according to the third aspect, since a cylindrical heat shield having reflectivity is provided on the inner peripheral surface or the outer peripheral surface of the furnace port, the vicinity of the furnace port is provided. Can further improve the heat insulation.

(4) According to the vertical heat treatment apparatus of the fourth aspect, since the cover material having reflectivity is provided on the upper surface of the lid, the heat insulation of the layer at the furnace port can be improved. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a vertical heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a heat insulating structure in the vertical heat treatment apparatus.

FIG. 3 is a side view of a heat shield plate constituting the heat insulating structure.

FIG. 4 is an exploded perspective view showing the structure of the heat shield plate.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 vertical heat treatment apparatus W semiconductor wafer (substrate to be processed) 2 furnace port 3 vertical heat treatment furnace 20 lid 21 wafer boat (substrate support) 22 heat insulating structure 32 support 33 heat shield plate 38 reflective film 39, 40 transparent quartz Layer 43 Heat shield 44 Cover material

Claims (4)

[Claims] A substrate support supporting a large number of substrates to be processed at predetermined intervals in a vertical direction is placed on an upper portion of a lid for opening and closing a furnace port at a lower portion of a vertical heat treatment furnace via a heat insulating structure. In a vertical heat treatment apparatus for heat-treating the object to be treated in a soaking region in a furnace, the heat-insulating structure has a plurality of columns, and a plurality of reflective members provided at predetermined intervals on the columns at predetermined intervals. A vertical heat treatment apparatus, comprising: 2. The vertical heat treatment apparatus according to claim 1, wherein said heat shield plate is formed of a reflective film and a transparent quartz layer covering a surface of said reflective film. 3. The vertical heat treatment apparatus according to claim 1, wherein a cylindrical heat shield having reflectivity is provided on an inner peripheral surface or an outer peripheral surface of the furnace port. 4. The vertical heat treatment apparatus according to claim 1, wherein a cover material having reflectivity is provided on an upper surface of the lid.