JP4031601B2 - Vertical heat treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vertical heat treatment apparatus.
[0002]
[Prior art]
For example, in the manufacture of semiconductor devices, as a semiconductor manufacturing apparatus that performs processing such as oxidation, diffusion, annealing, CVD, etc. on an object to be processed such as a semiconductor wafer, for example, a batch type vertical type capable of processing a large number of semiconductor wafers at a time A heat treatment apparatus is used. This vertical heat treatment apparatus accommodates a boat, which is a support member in which a large number of semiconductor wafers are arranged and supported at a predetermined interval in the height direction, in a processing container, and introduces a processing gas into the processing container to generate a predetermined temperature. The semiconductor wafer is configured to be subjected to a predetermined process such as a film forming process by CVD.
[0003]
The processing container is provided with a gas introduction pipe for introducing a processing gas. The gas introduction pipe is, for example, a straight pipe that rises from the bottom to the top in the processing container and has its tip closed, and its wall In addition, a gas injection hole (also referred to as a dispersion injector) in which gas injection holes for injecting a processing gas to a semiconductor wafer are formed at a predetermined interval is used.
[0004]
[Problems to be solved by the invention]
However, in the vertical heat treatment apparatus provided with the gas introduction pipe, a pressure gradient is generated in the gas introduction pipe, and the flow rate of the processing gas from the gas injection hole decreases from the gas introduction port side to the tip of the gas introduction pipe. Therefore, a variation (non-uniformity) occurs in the supply amount of the processing gas between planes or between planes (height direction) of a large number of semiconductor wafers supported by the boat, and processing (for example, film formation) occurs in the plane direction. There has been a problem that non-uniformity of the film thickness in the treatment and the doping concentration in the diffusion treatment occurs.
[0005]
In order to solve this problem, for example, the diameter of the gas injection hole of the gas introduction pipe is increased from the gas introduction port side to the tip (the former), or a plurality of gas introduction pipes having different lengths are provided. A gas flow rate control (the latter) has been proposed for each, but the former requires a great deal of time and adjustment to optimize the gas ejection amount, and the latter is not flexible for changing conditions. There are problems such as complicated gas supply system facilities and increased costs.
[0006]
Therefore, the present invention has been made in consideration of the above-described circumstances, and it is possible to achieve a uniform gas supply amount in the direction between the surfaces of the object to be processed with a simple configuration, and to achieve a uniform process in the direction between the surfaces. An object is to provide a vertical heat treatment apparatus.
[0007]
[Means for Solving the Problems]
Among the present inventions, the invention according to claim 1 supports a number of objects to be processed at predetermined intervals in the height direction, accommodates them in a processing container, introduces a processing gas into the processing container, and supplies a predetermined temperature. In the vertical heat treatment apparatus for processing an object to be processed, a gas is formed in the processing container, which is a straight pipe that rises from the bottom to the top and whose tip is closed, and injects a processing gas to the object to be processed on the tube wall A first gas introduction pipe having ejection holes formed at predetermined intervals, and a U-shaped pipe that rises from the bottom to the top and is folded from the top to the bottom and closed at the tip, and is the part of the part folded back to the bottom. The wall is provided with a second gas introduction pipe in which gas ejection holes for injecting a processing gas to the object to be processed are formed at predetermined intervals.
[0008]
The invention according to claim 2 is the vertical heat treatment apparatus according to claim 1, wherein a flow rate control mechanism is provided in each gas supply system of the first gas introduction pipe and the second gas introduction pipe. It is characterized by.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 is a longitudinal sectional view of a vertical heat treatment apparatus showing an embodiment of the present invention, FIG. 2 is a view showing a configuration of a gas introduction pipe in the vertical heat treatment apparatus, and FIG. 3 is an AA excluding the heater of FIG. It is arrow schematic sectional drawing.
[0010]
As shown in FIG. 1, a vertical heat treatment apparatus, which is a semiconductor manufacturing apparatus, supports a large number of, for example, about 150 objects to be processed, for example, semiconductor wafers w, arranged at predetermined intervals in the height direction on a bow and 1, which are support tools. The semiconductor wafer w is housed in a reaction tube 2 that is a processing vessel, and a processing gas is introduced into the reaction tube 2 so that a predetermined heat treatment, for example, a CVD process is performed on the semiconductor wafer w at a predetermined temperature.
[0011]
Around the reaction tube 2, there is provided a heater 3 as a heating means for heating the inside of the furnace to a desired temperature, for example, about 600 to 1200 ° C. The heater 3 is configured by arranging a heating resistance wire (heating resistor) 5 in a meandering manner in the circumferential direction or in a spiral shape in the longitudinal direction on the inner circumference of a cylindrical heat insulating material 4 surrounding the reaction tube 2. ing. The heater 3 may be divided into a plurality of zones in the height direction and configured to be capable of temperature control independently for each zone. The outside of the heat insulating material 4 is covered with a water cooling jacket (not shown).
[0012]
The heater 3 is installed on a base plate 6. The heater 3 blows cooling air into the space between the reaction tube 2 and the heater 3, and forcibly exhausts the furnace by a forced exhaust mechanism (not shown) provided on the ceiling of the heat insulating material 4. It may be a forced air cooling heater that can be rapidly cooled. By employing the forced air cooling heater, the vertical heat treatment apparatus can be configured as a rapid heating / cooling furnace.
[0013]
The reaction tube 2 is made of a heat-resistant and corrosion-resistant material such as quartz, and is formed in a vertically long cylindrical shape with the upper end closed and the lower end opened as a furnace port. In the present embodiment, a short cylindrical manifold 7 is attached to the lower end portion of the reaction tube 2 in order to make the furnace port a highly airtight structure so that heat treatment in which the pressure inside the furnace is reduced, for example, low pressure CVD treatment, is possible. . The manifold 7 is made of a material having heat resistance and corrosion resistance, such as stainless steel.
[0014]
On the side wall of the manifold 7, a gas introduction pipe 8 (described later) for introducing processing gas and inert gas into the furnace and a thermometer (not shown) are inserted and fixed in an airtight manner. An exhaust section (exhaust port) 9 for exhausting is provided. An exhaust system having a pressure control mechanism is connected to the exhaust unit 13, and this exhaust system is connected to a factory exhaust system (not shown).
[0015]
The upper end portion of the manifold 7 is attached and fixed to the base plate 6, and the lower end portion of the manifold 7 is opened as a furnace port. Below the reaction tube 2, a lid body 11 that is brought into contact with the lower opening end of the manifold 7 through an airtight material (not shown) such as an O-ring and hermetically closes the furnace port is provided by an elevating mechanism 12. Yes. The boat 1 is placed on the lid 11 via a heat insulating cylinder 13. The elevating mechanism 12 carries the boat 1 into and out of the reaction tube 2 and opens and closes the lid 11. Further, the lid 11 is provided with a rotating mechanism 14 that rotates the boat 1 together with the heat insulating cylinder 13 in order to uniformly process the semiconductor wafer w in the surface.
[0016]
The reaction tube 2 of the present embodiment has a double tube structure composed of an inner tube 2a and an outer tube 2b. The outer tube 2b is closed at the upper end, opened at the lower end, and has a flange portion 2f at the open end. The outer pipe 2b is brought into contact with the upper end surface (upper opening end) of the manifold 7 through an airtight member (not shown) such as an O-ring, and the flange portion 2f is fixed with a flange presser 15 so that the manifold 2 7 is installed in an airtight manner.
[0017]
The inner pipe 2a has an upper end and a lower end opened. The lower end of the inner tube 2a is detachably attached to the inner periphery of the manifold 7 on the lower end opening (furnace port) side, and is concentrically disposed inside the outer tube 2b.
[0018]
On the other hand, the gas introduction pipe 8 is bent in an L shape at the base end side on the gas introduction port 8a side, and is hermetically inserted and fixed to the introduction portion 9, and the distal end side of the inner pipe 2a of the inner pipe 2a is inserted into the reaction tube 2. It is installed in a state of vertically rising along the inner wall. As shown in FIG. 2, the gas introduction pipe 8 includes a first gas introduction pipe 8A that is a dispersion injector and a second gas introduction pipe 8B that is a reverse dispersion injector.
[0019]
The first gas introduction pipe 8A is a straight pipe made of quartz (straight pipe) whose rising tip 8e is closed from the lower side to the upper side, and the processing gas is sprayed onto the semiconductor wafer w onto the pipe wall. The gas ejection holes 16 are formed at a predetermined interval, for example, the same interval as the arrangement pitch of the semiconductor wafers w. All the gas ejection holes 16 formed in the first gas introduction pipe 8A have the same hole diameter. The gas ejection holes 16 correspond to the upper positions of the semiconductor wafers w so as to supply the processing gas horizontally along the surface to be processed (upper surface) of the semiconductor wafers w supported by the boat 1. Is formed.
[0020]
The second gas introduction pipe 8B is made of a quartz U-shaped pipe that rises from the bottom to the top and is folded from the top to the bottom and closed at the tip 8e. The gas injection holes 17 for injecting the processing gas to the semiconductor wafer w are formed at a predetermined interval, for example, the same interval as the arrangement pitch of the semiconductor wafers w. That is, the second gas introduction pipe 8B has a vertical rising portion 8h and a vertical falling portion 8g extending downward from the upper end of the rising portion 8h via an inverted U-shaped bent portion 8u. The gas ejection holes 17 formed in the descending portion 8g correspond to the gas ejection holes 16 of the first gas introduction pipe 8A in an upside down relationship.
[0021]
The gas ejection holes 17 of the second gas introduction pipe 8B have the same diameter as the gas ejection holes 16 of the first gas introduction pipe 8A, and each semiconductor wafer supported by the boat 1 has the same diameter. It is formed corresponding to the position of w. The gas introduction hole 16 of the first gas introduction pipe 8A and the gas ejection hole 17 of the second gas introduction pipe 8B may have the same or different hole diameters.
[0022]
Gas supply systems 18a and 18b communicating with a gas supply source are connected to the gas introduction ports 8a of the first gas introduction pipe 8A and the second gas introduction pipe 8B, and flow rates are connected to the gas supply systems 18a and 18b. Control mechanisms 19a and 19b are provided. In this case, the gas supply source may be common, or may be separate sources that supply the same kind of processing gas.
[0023]
In the first gas introduction pipe 8A, the amount of the processing gas ejected from the gas ejection hole 16 decreases as it goes above the gas introduction pipe 8A, whereas in the second gas introduction pipe 8B, On the contrary, the amount of the processing gas ejected decreases as it goes below the gas introduction pipe 8B. Therefore, by combining these two gas introduction pipes 8A and 8B, the gas in the direction between the surfaces of the semiconductor wafer w can be obtained with a simple configuration. The supply amount can be made uniform.
[0024]
Note that FIG. 2 shows a configuration in which the first gas introduction pipe 8A and the second gas introduction pipe 8B are arranged to face each other in order to illustrate how the gas supply amount becomes uniform in the inter-plane direction. Specifically, the first gas introduction pipe 8A and the second gas introduction pipe 8B are arranged in parallel in the reaction tube 2 as shown in FIG.
[0025]
Next, the operation of the vertical heat treatment apparatus having the above configuration will be described. The boat 1 in which a large number of semiconductor wafers w are arranged and stored at a predetermined pitch in the height direction is placed on the heat insulating cylinder 13, and the lid 11 is raised by the elevating mechanism 12, whereby the boat 1 is placed in the reaction tube 2. While being accommodated in the reactor core, the lower end opening (furnace port) of the manifold 7 is sealed with the lid 11.
[0026]
Next, after the inside of the reaction tube 2 is replaced with an inert gas such as nitrogen gas, the temperature inside the reaction tube 2 is raised to a predetermined temperature by the heater 3, and the first and second gas introduction pipes 8 </ b> A, A processing gas is supplied from 8B to perform a predetermined process such as a CVD process or a diffusion process. In this case, the flow rate of the processing gas is controlled by the flow rate control mechanisms 19a and 19b from the processing gas supply source to the first gas introduction pipe 8A and the second gas introduction pipe 8B through the processing gas supply systems 18a and 18b, respectively. Supplied.
[0027]
In the first gas introduction pipe 8A, the amount of the processing gas ejected from the gas ejection hole 16 decreases as it goes above the gas introduction pipe 8A, whereas in the second gas introduction pipe 8B, Since the flow rate of the processing gas decreases toward the lower side of the gas introduction pipe 8B, by combining these two gas introduction pipes 8A and 8B, the gas supply amount in the direction between the surfaces of the semiconductor wafer w can be made uniform. Further, uniform processing in the inter-surface direction, for example, CVD processing can achieve uniform film thickness, and diffusion processing can achieve uniform doping concentration.
[0028]
As described above, according to the vertical heat treatment apparatus, a large number of semiconductor wafers w are supported at predetermined intervals in the height direction and are accommodated in the reaction tube 2, and a processing gas is introduced into the reaction tube 2 to obtain a predetermined temperature. In the vertical heat treatment apparatus for processing the semiconductor wafer w, the reaction tube 2 is a straight tube that rises from the bottom to the top and closes the tip 8e, and injects a processing gas to the semiconductor wafer w on the tube wall. The first gas introduction pipe 8A is formed with gas ejection holes 16 formed at predetermined intervals, and a U-shaped pipe that rises from the bottom to the top and is folded from the top to the bottom and closed at the tip, and is folded back to the bottom. Since the second gas introduction pipe 8B in which the gas ejection holes 17 for injecting the processing gas to the semiconductor wafer w are formed at a predetermined interval is provided on the tube wall of the part, the semiconductor wafer w can be configured with a simple configuration. In the face-to-face direction Hakare the uniformity of supply amount, Hakare the uniformity of the processing in the inter-plane direction, thereby improving the yield.
[0029]
The vertical heat treatment apparatus has the simple configuration of simply adding the inverse dispersion injector 8B to the conventional dispersion injector 8A, and can achieve the effects described above. Since two gas supply systems are sufficient, the equipment cost can be reduced. be able to. In addition, since the gas supply systems 18a and 18b of the first gas introduction pipe 8A and the second gas introduction pipe 8B are provided with flow control mechanisms 19a and 19b, respectively, in the direction between the surfaces of the semiconductor wafer w. The balance of the process gas supply amount can be easily adjusted.
[0030]
The present invention relates to D-Poly (treatment using, for example, phosphine as a processing gas and doping phosphorus into a silicon film, also referred to as P-Doped-Polysilicon), F-Poly (the temperature inside the furnace is not given a temperature gradient). The process gas is also applicable to various processes such as a process for forming a silicon film using monosilane as a processing gas, also referred to as “Flat-Polysilicon”.
[0031]
Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to the above-described embodiments, and various design changes and the like can be made without departing from the scope of the present invention. is there. For example, in order to secure a horizontal flow of the processing gas in the reaction tube, an exhaust port may be formed in the tube wall of the inner tube facing the first and second gas introduction tubes. As a reaction tube which is a processing vessel, a double tube structure is adopted in the embodiment, but a single tube structure may be used. The vertical heat treatment apparatus according to the present invention can be applied not only to CVD processing and diffusion processing, but also to other processing such as oxidation processing. As an object to be processed, for example, a glass substrate or an LCD substrate can be applied in addition to the semiconductor wafer.
[0032]
【The invention's effect】
In short, according to the present invention, the following effects can be obtained.
[0033]
(1) According to the first aspect of the present invention, a large number of objects to be processed are supported at predetermined intervals in the height direction and are accommodated in a processing container, and a processing gas is introduced into the processing container and a predetermined temperature is set. In the vertical heat treatment apparatus for processing an object to be processed, a gas is formed in the processing container, which is a straight pipe that rises from the bottom to the top and whose tip is closed, and injects a processing gas to the object to be processed on the tube wall A first gas introduction pipe having ejection holes formed at predetermined intervals, and a U-shaped pipe that rises from the bottom to the top and is folded from the top to the bottom and closed at the tip, and is the part of the part folded back to the bottom. Since the wall is provided with a second gas introduction pipe in which gas ejection holes for injecting a processing gas to the object to be processed are formed at a predetermined interval, the surface of the object to be processed can be formed in a simple configuration. The gas supply amount can be made uniform, and the treatment in the plane direction can be made uniform. That.
[0034]
(2) According to the invention of claim 2, each gas supply system of the first gas introduction pipe and the second gas introduction pipe is provided with a flow rate control mechanism. It is possible to easily adjust the balance of the process gas supply amount in the inter-direction.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a vertical heat treatment apparatus showing an embodiment of the present invention.
FIG. 2 is a view showing a configuration of a gas introduction pipe in the vertical heat treatment apparatus.
FIG. 3 is a schematic cross-sectional view taken along the line AA excluding the heater of FIG. 1;
[Explanation of symbols]
w Semiconductor wafer (object to be processed)
2 reaction tube (processing vessel)
8A First gas introduction pipe 8B Second gas introduction pipe 16, 17 Gas ejection holes 18a, 18b Gas supply systems 19a, 19b Flow rate control mechanism

Claims (2)

In a vertical heat treatment apparatus that supports a large number of objects to be processed at predetermined intervals in a height direction, accommodates them in a processing container, introduces a processing gas into the processing container, and processes the objects to be processed at a predetermined temperature. 1st gas which consists of the straight pipe which stood up from the lower part to the upper part in the said process container, and the front-end | tip was obstruct | occluded, and formed the gas injection hole which injects process gas with respect to a to-be-processed object at the predetermined | prescribed space | interval It consists of an introduction pipe and a U-shaped pipe that rises from the bottom to the top and is folded from the top to the bottom and closed at the tip, and the processing gas is sprayed onto the object to be treated onto the pipe wall of the part folded back to the bottom. A vertical heat treatment apparatus provided with a second gas introduction pipe having gas ejection holes formed at predetermined intervals. The vertical heat treatment apparatus according to claim 1, wherein a flow rate control mechanism is provided in each gas supply system of the first gas introduction pipe and the second gas introduction pipe.

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