JP4468555B2 - Heat treatment apparatus and heat treatment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat treatment apparatus and a heat treatment method.
[0002]
[Prior art]
In the manufacture of semiconductor devices, various types of heat treatment apparatuses are used to perform processes such as oxidation, diffusion, and CVD (Chemical Vapor Deposition) on an object to be processed such as a semiconductor wafer. As one of them, there is known a vertical heat treatment apparatus capable of heat treating a plurality of objects to be processed at one time.
[0003]
As shown in FIG. 7, this heat treatment apparatus accommodates a plurality of wafers w in the processing container 2 at a predetermined interval in the height direction, and a heater (heating source) 10 provided around the processing container 2. The wafer w is heated and subjected to a predetermined heat treatment. Reference numeral 12 denotes a quartz boat on which a plurality of wafers w are mounted at predetermined intervals in the height direction, and 13 is a lid for closing the opening of the processing container 2.
[0004]
[Problems to be solved by the invention]
However, in the heat treatment apparatus, since the heater 10 exists in the extending direction of the peripheral edge (edge) of the wafer w, that is, on the peripheral side, the temperature of the peripheral edge of the wafer rises first during heating, and the wafer is delayed. The temperature rises at the center. This delay in temperature rise causes an in-plane temperature difference of the wafer, which causes a slip (crystal deviation) in the wafer. In order to prevent this slip, in conventional heat treatment equipment and heat treatment methods, the temperature increase / decrease rate was adjusted for each temperature range, but the temperature increase / decrease rate must be optimized for each temperature range. In addition, since the rate is lowered, it is difficult to achieve the performance of the heater around the wafer.
[0005]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heat treatment apparatus and a heat treatment method that can reduce an in-plane temperature difference of an object to be processed and can prevent slipping. .
[0006]
[Means for Solving the Problems]
Among the present inventions, the invention according to claim 1 is a method in which a plurality of objects to be processed are heated from the peripheral portion around a processing container that accommodates a plurality of objects to be processed held in a holding tool at predetermined intervals in the height direction. A first heater is provided, and at least a second heater for heating and raising the temperature of the object to be processed from a central portion is provided in the processing container, and the second heater is a lower surface heater provided below the processing container; characterized in that it comprises a top heater provided above the outside processing chamber and an intermediate heater provided in the height direction intermediate portion of the retainer.
[0007]
According to a second aspect of the present invention, in the heat treatment apparatus according to the first aspect, the second heater is formed in a plane shape parallel to the object to be processed, and the temperature can be controlled concentrically into a plurality of regions. It is configured .
[0008]
According to a third aspect of the present invention, there is provided a first heater that heats and raises the temperature of the object to be processed from a peripheral portion around a processing container that accommodates a plurality of objects to be processed held in a holding tool at predetermined intervals in the height direction. And at least a second heater that heats and raises the temperature of the object to be processed from the central portion is disposed in the processing container. The second heater is a lower surface heater provided below the processing container, and an outer surface of the processing container. a top heater provided above the, and an intermediate heater provided in the height direction intermediate portion of the holder, these first heater and second heater, the peripheral portion and the object to be processed It is characterized in that a predetermined heat treatment is performed by heating from the center.
[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 heat treatment apparatus showing an embodiment of the present invention, FIG. 2 is a graph showing a temperature difference in a wafer surface by a first heater, and FIG. 3 is a temperature difference in a wafer surface by a second heater. FIG. 4 is a diagram schematically showing an embodiment of the present invention.
[0010]
1 to 4, reference numeral 1 denotes a vertical heat treatment apparatus. The heat treatment apparatus 1 accommodates a plurality of objects to be processed, for example, semiconductor wafers w at predetermined intervals in the height direction, and performs a predetermined heat treatment, for example, a CVD process. A processing container (process tube) 2 is provided. The processing container 2 is formed of a material having heat resistance and corrosion resistance, for example, quartz glass.
[0011]
In the present embodiment, the processing container 2 has a double tube structure of an inner tube 2a and an outer tube 2b. The inner tube 2a is open at the upper and lower ends. The outer tube 2b has an upper end closed and a lower end opened. In addition, the processing container 2 may consist only of the outer tube 2b.
[0012]
In the present embodiment, a gas introduction part (introduction port) 3 that introduces a processing gas or an inert gas into the processing container 2 and an exhaust part (exhaust port) that exhausts the inside of the processing container 2 are disposed below the processing container 2. ) 4 and a short cylindrical manifold 5 is provided. The manifold 5 is formed of a material having heat resistance and corrosion resistance, for example, stainless steel.
[0013]
The gas introduction unit 3 is connected to a gas supply system pipe leading to a gas source. An exhaust system having a vacuum pump and a pressure control mechanism is connected to the exhaust unit 4 so that the inside of the processing container 2 can be controlled to a predetermined processing pressure. In a state controlled by this processing pressure, the processing gas introduced from the gas introduction unit 3 rises in the inner tube 2a of the processing container 2 and is subjected to a predetermined heat treatment of the wafer w, and then the inner tube 2a and the outer tube 2a. The annular passage between the pipe 2b is lowered and exhausted from the exhaust part 4.
[0014]
A flange portion 5 f is formed at the upper end of the manifold 5, and a lower end flange portion 2 f of the outer tube 2 b is placed on the upper surface of the upper end flange portion 5 f and is bonded and fixed by a flange presser 6. Between the upper end flange portion 5f of the manifold 5 and the lower end flange portion 2f of the outer tube 2b, for example, an O-ring as a sealing means is interposed (not shown). An inner tube support portion 7 for supporting the inner tube 2 a is provided at the center of the manifold 5.
[0015]
The manifold 5 is attached to the lower part of the base plate 8, and above the base plate 8, around the processing vessel 2, the wafer w in the processing vessel 2 is heated from the peripheral edge to a predetermined heat treatment temperature. A first heater 10 is provided for heating. The first heater 10 in the illustrated example is composed of a carbon heater in which, for example, a rod-shaped resistance heating element or a carbon fiber bundle is knitted into a vertically long shape, and this is enclosed in a quartz glass or alumina sealed member. In a state, it is arranged in a cylindrical shape so as to surround the periphery of the processing container 2. The first heater 10 includes a main heater 10a that heats the periphery of the processing container 2, and a sub-heater 10b that heats the periphery of the upper and lower ends of the processing container 3, and the main heater 10a and the sub-heater 10b are arranged in the circumferential direction. It is preferable that they are arranged alternately.
[0016]
A cover 11 having a cylindrical water-cooling structure with a closed upper end is provided above the base plate 8 so as to cover the outside of the first heater 10 and the periphery and the top of the processing container 2. The first heater 10 is attached to the above. The first heater is preferably the one shown in the figure, but includes a cylindrical (cylindrical) heat insulating material that surrounds the processing vessel 2, and a resistance heating wire is provided on the inner periphery of the cylindrical heat insulating material. It may be arranged in a spiral shape or a meandering shape, and may be configured to be capable of temperature control divided into a plurality of regions (zones) in the height direction.
[0017]
In order to mount and hold a plurality of, for example, about 50 semiconductor wafers w in the height direction at predetermined intervals in the processing container 2, the wafers w are held by a boat 12 made of, for example, quartz glass, which is a holding tool. For example, a stainless steel lid 13 that seals the lower end opening (furnace port) of the manifold 5 is placed via a turntable 14.
[0018]
The rotary table 14 has a rotary column 15 erected from the upper center of the lid 13 to hold the boat 12 in the heat treatment region in the processing vessel 2, and the rotary column 15 is driven to rotate below the lid 13. A driving unit 16 is provided. In addition, a cylindrical quartz glass heat insulating cylinder 18 having a plurality of quartz glass heat shields 17 arranged at appropriate intervals in the vertical direction is installed on the upper portion of the lid 13 as a furnace port heat insulating heat retaining means. A rotary support column 15 of the rotary table 14 is rotatably passed through the axis of the heat insulating cylinder 18.
[0019]
At least in the processing container 2, a second heater 20 is provided for heating the wafer w from the center. The second heater 20 is provided on the center line of the wafer w in order to heat and heat the wafer w from the center. The second heater 20 is formed in a plane parallel to the wafer w, and is preferably provided as a lower surface heater 20a at least in the lower part of the processing container 2.
[0020]
In the illustrated example, an upper surface heater 20 b as a second heater is also provided above the processing container 2. The second heater 20 is preferably composed of a carbon heater in which, for example, a carbon fiber bundle is knitted into a vertically long shape, and this is wired in a flat shape and sealed in a sealed member made of quartz glass or alumina.
[0021]
The second heater 20 is provided in the lower part of the processing container 2, that is, on the upper part of the heat insulating cylinder 18, and on the upper part of the outer side of the processing container 2, that is, on the ceiling portion of the cover body 13, as shown in the illustrated example. The upper surface heater 20b is preferable. The upper surface heater 20b may be provided above the processing container 2, for example, above the boat 12.
[0022]
As the second heater, when the number of processed wafers w is as large as about 150, for example, as shown in FIG. 4, an intermediate heater 20c is provided at an intermediate portion of the wafer row, that is, an intermediate portion in the height direction of the boat 12. It is preferable that The upper surface heater 20b and the lower surface heater 20a have not only heating of the wafer w, but also functions of suppressing heat dissipation from above and below the processing container 2, respectively.
[0023]
Below the processing container 2, an elevating mechanism (not shown) for raising and lowering the lid 13 to open and close the lid 13 and loading and unloading the boat 12 with respect to the processing container 2 is provided, and a loading which is a work area thereof is provided. An area 21 is provided. For example, an O-ring (not shown) serving as a sealing means is provided at the joint between the lower end (opening end) of the manifold 5 and the lid 13.
[0024]
In the above configuration, as shown in FIG. 4, a wafer ws with a temperature sensor (for example, a thermocouple) is mounted on the boat 12, and the temperature is raised by heating only from the first heater 10 (side surface heating or side surface heating). FIG. 2 and FIG. 3 are graphs showing the results of the temperature increase test performed in the case where the temperature was raised by heating only by the lower heater 20a of the second heater 20 (lower surface heating). In the case of side surface heating, the temperature is raised from the peripheral edge of the wafer as shown in the graph of FIG. 2, and in the case of lower surface heating, the temperature is raised from the center of the wafer as shown in the graph of FIG. I understand that.
[0025]
Therefore, in actual operation, temperature rise data of the first heater 10 and the second heater 20 is collected, and the first heater 10 and the second heater 20 are controlled by the controller based on the temperature rise data. However, the in-plane temperature difference of the wafer w may be reduced or eliminated by the balance between the heating of the first heater 10 and the second heater 20.
[0026]
Next, the operation of the heat treatment apparatus having the above configuration will be described. First, the boat 12 on which the transfer of the wafer w has been completed is placed on the rotary table 14 on the lid 13 in the loading area 21. Next, the boat 12 is carried into the processing container 2 from the lower end opening (the lower end opening of the manifold 5) by ascending the lid body 13 by the elevating mechanism, and the opening is airtightly closed by the lid body 13.
[0027]
Then, the inside of the processing container 2 is controlled to a predetermined pressure or degree of vacuum by the reduced pressure exhaust from the exhaust unit 4 by the exhaust system, and is controlled to a predetermined processing temperature by the first heater 10 and the second heater 20 to rotate. While the boat 12 is rotated by the table 14, a processing gas is introduced into the processing container 2 from the gas introduction unit 3, and a predetermined heat treatment such as a CVD process is started on the wafer w. In particular, by controlling the outputs of the first heater 10 and the second heater 20, the temperature of the wafer w is increased by heating from the peripheral portion and the central portion, thereby reducing or eliminating the in-plane temperature difference of the wafer w. Is uniformly heat-treated in the plane.
[0028]
When the predetermined heat treatment is completed, first, the first and second heaters 10 and 20 are turned off, the introduction of the processing gas is stopped, and the inside of the processing container 2 is purged by introducing the inert gas. Next, the rotary table 14 is stopped, the lid 13 is lowered, the inside of the processing container 2 is opened, and the boat 2 may be carried out to the loading area 21.
[0029]
As described above, according to the heat treatment apparatus 1, the first heater 10 that heats and raises the temperature of the wafer w from the peripheral portion is provided around the processing container 2 that accommodates a plurality of wafers w at predetermined intervals in the height direction. Since at least the second heater 20 for heating and heating the wafer w from the central portion is provided in the processing container 2, the wafer w is heated from the peripheral portion and the central portion to increase the in-plane temperature difference of the wafer w. Can be reduced, and slipping can be prevented.
[0030]
Further, since the second heater 20 is formed in a plane parallel to the wafer w and is provided at least in the lower part of the processing chamber 2, the temperature of the wafer can be efficiently heated from the center. It becomes. Furthermore, since the second heater 20 is made of a carbon heater, the wafer w is hardly contaminated even if it is provided in the processing container 2, and the wafer w can be quickly heated to a desired high temperature. Moreover, since the 1st heater 10 is not employ | adopting a heat insulating material and is provided with the cover body 11 of the water cooling structure, rapid temperature rise and rapid temperature fall are possible.
[0031]
Furthermore, according to the heat treatment method, the first heater 10 for heating and heating the wafer w from the peripheral portion is arranged around the processing container 2 that accommodates a plurality of wafers w at predetermined intervals in the height direction, and the Also, a second heater 20 for heating and heating the wafer w from the central portion is disposed in the processing container 2, and the wafer w is simultaneously removed from the peripheral portion and the central portion by the first heater 10 and the second heater 20. Since a predetermined heat treatment is performed by heating and raising the temperature, the in-plane temperature difference of the wafer w can be reduced, and slipping can be prevented.
[0032]
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 the above embodiment, a CVD process is exemplified as an example of the heat treatment, but the heat treatment apparatus of the present invention can perform, for example, a diffusion process, an oxidation process, an annealing process, etc. in addition to the CVD process. . Moreover, in the said embodiment, although the heat processing apparatus provided with the manifold in the processing container was illustrated, the heat processing apparatus of this invention does not need to be provided with the manifold in the processing container. In addition to the semiconductor wafer, the object to be processed may be, for example, an LCD substrate or a glass substrate.
[0033]
As shown in FIG. 5, the second heater 20 may be configured to be concentrically divided into a plurality of regions (zones) so that the temperature can be controlled. Alternatively, as shown in FIG. These regions (zones) may be divided so that the temperature can be controlled, or a combination thereof may be used.
[0034]
【The invention's effect】
In short, according to the present invention, the following effects can be obtained.
[0035]
(1) According to the invention of claim 1, the temperature of the object to be processed is heated from the peripheral portion around the processing container that accommodates the plurality of objects to be processed while being held by the holder at predetermined intervals in the height direction. A first heater is provided, and at least a second heater for heating and raising the temperature of the object to be processed from a central portion is provided in the processing container, and the second heater is a lower surface heater provided below the processing container; a top heater provided above the outside processing chamber, because of an intermediate heater provided in the height direction intermediate portion of the retainer, and the heating was raised from the peripheral portion and the central portion of the object to be processed The in-plane temperature difference of the object to be processed can be reduced, and slipping can be prevented.
[0036]
(2) According to the invention of claim 2, the second heater is formed in a plane shape parallel to the object to be processed, and is configured to be temperature-controllable concentrically divided into a plurality of regions. Therefore, it is possible to efficiently raise the temperature of the object to be processed from the center.
[0037]
(3) According to the invention of claim 3, the temperature of the object to be processed is heated from the peripheral portion around the processing container that accommodates the plurality of objects to be processed while being held by the holder at predetermined intervals in the height direction. A first heater is disposed, and at least a second heater that heats and raises the temperature of the object to be processed from a central portion is disposed in the processing container, and the second heater is a lower surface heater provided below the processing container. When the upper surface heater provided on the upper outside the processing container, and an intermediate heater provided in the height direction intermediate portion of the holder, these first heater and second heater, to be treated Since the body is heated and heated from the peripheral part and the central part to perform a predetermined heat treatment, the in-plane temperature difference of the object to be processed can be reduced by heating and heating from the peripheral part and the central part, and slip Can be prevented.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a heat treatment apparatus showing an embodiment of the present invention.
FIG. 2 is a graph showing a temperature difference in a wafer surface by a first heater.
FIG. 3 is a graph showing a temperature difference in a wafer surface by a second heater.
FIG. 4 is a diagram schematically showing an embodiment of the present invention.
FIG. 5 is a schematic plan view showing an example of zone division of a second heater.
FIG. 6 is a schematic plan view showing another example of zone division of the second heater.
FIG. 7 is a diagram schematically showing a conventional heat treatment apparatus.
[Explanation of symbols]
w To-be-processed object 1 Heat processing apparatus 2 Processing container 10 1st heater 20 2nd heater

Claims (3)

A first heater that heats the object to be processed from its peripheral portion is provided around a processing container that accommodates a plurality of objects to be processed while being held by a holder at predetermined intervals in the height direction, and at least the processing container A second heater that heats and raises the temperature of the object to be processed from the center, and the second heater includes a lower surface heater provided below the processing container, and an upper surface heater provided above the processing container. the heat treatment apparatus being characterized in that an intermediate heater provided in the height direction intermediate portion of the retainer.   2. The heat treatment according to claim 1, wherein the second heater is formed in a plane shape parallel to the object to be processed, and is configured to be temperature-controllable in a plurality of regions concentrically. apparatus. A first heater that heats the object to be processed from its peripheral portion is disposed around a processing container that accommodates a plurality of objects to be processed while being held by a holder at a predetermined interval in the height direction. A second heater that heats and raises the temperature of the object to be processed from the central portion is disposed in the container, and the second heater includes a lower surface heater provided below the processing container and an upper surface provided outside the processing container. a heater, and an intermediate heater provided in the height direction intermediate portion of the holder, these first heater and second heater, is Atsushi Nobori from the peripheral portion and the central portion of the object to be processed And a predetermined heat treatment.

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