JP2893670B2 - Method for manufacturing semiconductor device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device for heat-treating a semiconductor wafer. 2. Description of the Related Art Conventional methods for manufacturing a semiconductor device include:
A plurality of semiconductor wafers are vertically stacked with a space therebetween in a vertically long processing chamber, arranged horizontally, and the processing chamber is heated by a heater, and a normal temperature processing is performed from above the semiconductor wafer in the processing chamber. A method for manufacturing a semiconductor device has been developed which heat-treats a semiconductor wafer which supplies a gas and exhausts a processing gas from a lower portion of the processing chamber. For example, as an example,
There is JP-A-56-91417. However, in the conventional method of manufacturing a semiconductor device of this type, the density of a normal-temperature processing gas supplied from a processing gas supply port during heat treatment of a semiconductor wafer is reduced. Since the density of the high-temperature processing gas is significantly higher than that of the high-temperature processing gas, and no consideration has been given to the point that a non-uniform downward flow of the processing gas involving the high-temperature processing gas in the processing chamber as schematically shown in FIG. Due to this uneven flow of the processing gas, the semiconductor wafer placed laterally in the processing chamber comes into contact with the non-uniform processing gas having a mixture of low and high temperatures, and there is a problem that uniform heat treatment cannot be performed. Was. In particular, with the increase in the density of integrated circuits, the need for more uniform heat treatment has increased. As a conventional method of manufacturing a semiconductor device, a method of preheating a processing gas supplied to a processing chamber is described in a microfilm of Japanese Utility Model Application No. 54-104693 (Japanese Utility Model Application Laid-Open No. 56-21439). Is a type in which a plurality of semiconductor wafers are arranged vertically in a horizontal processing chamber at intervals with a space therebetween in a horizontal direction, and a processing gas is supplied from a side surface of the processing chamber and forcedly flows in a horizontal direction, This is completely different from the above-mentioned type in which the processing gas flows from the upper part to the lower part, and does not show that uneven heat treatment is performed by a non-uniform downward flow of the processing gas due to a difference in density of the processing gas. [0005] It is an object of the present invention to arrange a plurality of semiconductor wafers in a vertically elongated processing chamber in a vertically stacked manner with a space therebetween and to place the semiconductor wafers horizontally. A method of manufacturing a semiconductor device, comprising: oxidizing and heat-treating a semiconductor wafer that supplies a processing gas from an upper portion of the semiconductor wafer and exhausts a processing gas from a lower portion of the processing chamber.
An object of the present invention is to provide a method of manufacturing a semiconductor device capable of preventing the generation of a non-uniform downward flow of a processing gas due to a difference in density between the processing gas flowing from above the semiconductor wafer and uniformly heat-treating the semiconductor wafer. is there. SUMMARY OF THE INVENTION It is an object of the present invention to arrange a plurality of semiconductor wafers horizontally in a cylinder forming a vertically long processing chamber, with a plurality of semiconductor wafers being vertically stacked at intervals and provided to a heater. And heating the inside of the cylinder by oxidizing and heat-treating a semiconductor wafer that supplies a processing gas from an upper part of the semiconductor wafer in the cylinder and exhausts a processing gas from a lower part of the cylinder. the process gas supplied into the inner
With pre-heated at the outside and inside with a lower or al upper portion guided by <br/> the heater of the heater cylinder, guided to the top
The processing gas to be supplied to the heater below the semiconductor wafer.
Is achieved by increasing the amount of heat generated by heating . An embodiment of the present invention will be described below with reference to FIGS. 1 and 5. The cylindrical vertically elongated reaction tube 1 having a closed top is integrally formed with a vertically elongated inner cylinder 16 with a gap inside to form a double cylindrical shape. Reaction tube 1
A gap between the inner cylinder 16 and the inner cylinder 16 forms a gas passage 17. The inner cylinder 16 forming the processing chamber 22 has a processing gas supply port 24 provided at a central portion thereof at a closed top, and a transfer port 20 for the semiconductor wafer 4 provided at a lower portion thereof. The gas supply port 14 is provided integrally on the outer periphery of the lower end portion of the reaction tube 1, a plurality of processing gas gas supply ports 8 are provided in a part thereof, and communicates with the lower part of the gas passage 17. Processing gas such as oxygen, hydrogen and impurities is supplied from the air supply port 8 into the air supply port 14. The soaking tube 2 is provided with an air layer 10 so as to cover the entire reaction tube 1. The cylindrical heater 3 is provided outside the heat equalizing tube 2, the reaction tube 1, and the inner cylinder 16, and is vertically divided into a plurality. The heat insulating material 13 is provided so as to cover the tops of the heater 3 and the heat equalizing tube 2. The base 12 provided with the refractory bricks 11 and 11a includes a reaction tube 1, an inner cylinder 1
6 and the soaking tube 2. The refractory brick 11 is provided so as to cover the air supply port 14. The refractory brick 11a is provided to support the heater 3 and the heat insulating material 13. A basket 5 constituting a support for the semiconductor wafer 4 is configured so that a plurality of semiconductor wafers 4 can be placed side by side at intervals and stacked and stored on a basket stage 6. The loading mechanism 7 to which the basket stage 6 is attached is configured to be able to move up and down, and the basket 5 is moved from the transfer port 20 of the inner cylinder 16 to the processing chamber 2.
2. Processing room 22
The heater 3 is also arranged on the lower outer peripheral portion of the basket 5 arranged inside. The cap 9 attached to the intermediate portion of the loading mechanism 7
Move up and down so as to close the transfer port 20 of the inner cylinder 16 with the bottom portion 21 and a slight gap 19 in a state where the basket 5 is disposed in the processing chamber 22. The gap 19 constitutes an exhaust port for the processing gas, but a separate exhaust port may be provided to completely close the transfer port 20. Next, a method of manufacturing a semiconductor device will be described.
First, a plurality of semiconductor wafers 4 are stored side by side in the basket 5 at intervals, mounted on the basket stage 6, the loading mechanism 7 is moved upward, and the inside of the processing chamber 22 is passed through the transfer port 20 of the inner cylinder 16. The semiconductor wafer 4 is arranged at the upper center of the semiconductor wafer. At the same time, the cap 9 has a gap 19 serving as an exhaust port and closes the transport port 20. From this state, the heat treatment during dry oxidation and diffusion and the heat treatment during wet oxidation involving hydrogen combustion will be described separately. (1) The heat treatment at the time of dry oxidation and diffusion will be described. A normal-temperature processing gas in which oxygen, nitrogen, and impurities are appropriately mixed is supplied from a gas supply port 8 to a supply port 14. The supplied processing gas is supplied from the gas supply port 14 to the gas passage 17.
Leads to. On the other hand, by the heater 3, the heat equalizing tube 2, the reaction tube 1,
The gas passage 17 and the inside of the processing chamber 22 are heated. The processing gas supplied to the gas passage 17 is heated and gradually heated and raised while being heated, and flows into the top 18 of the processing chamber 22 from the supply port 24 at the top of the inner cylinder 16. Since the flowing processing gas is heated in advance, it is possible to prevent a non-uniform downward flow of the processing gas due to a difference in density of the processing gas in the processing chamber 22 as in the related art, and stored in the basket 5. The semiconductor wafer 4 can be uniformly heat-treated. After processing the semiconductor wafer 4 from the upper portion to the lower portion in this manner, the processing gas is discharged to the outside from an exhaust port formed at a lower end portion of the processing chamber 22. Further, since the processing gas to be supplied to the processing chamber 22 is guided from the lower part to the upper part outside the processing chamber 22 and preheated by the heater 3, the processing gas is guided from the lower part to the upper part inside the processing chamber. In comparison, there is an advantage that the processing chamber 22 is simplified, the semiconductor wafer storage property is good, and the temperature in the processing chamber 22 can be made non-uniform due to heat exchange with the processing gas flowing from the lower part to the upper part. . In order to make the temperature of the processing gas in contact with all the semiconductor wafers 4 stored in the basket 5 uniform, the inner cylinder 1
In order to eliminate the temperature difference between the processing gas in contact with the side wall surface (outer wall) of the gas passage 17 and the side wall surface (inner wall) of the basket 5, the heating value of the heater in the lower part in the vertical direction is made larger than that in the upper part in the vertical direction. As a result, the temperature inside the processing tank can be set to a predetermined temperature. (2) The heat treatment during wet oxidation accompanied by hydrogen combustion will be described. Oxygen and hydrogen supplied from the gas supply port 8 are combusted in the supply port 14 and become steam to move up the gas passage 17. The supply port 2 provided at the top 18 of the inner cylinder 16
4 descends to the semiconductor wafer 4 surface. In this case, contrary to the above-described dry oxidation, the calorific value of the heater below the vertical direction is made smaller than the calorific value of the heater above the vertical direction. Here, the temperature of the supply processing gas is increased by combustion at the air supply port 14, so that the temperature of the processing gas in contact with all the semiconductor wafer 4 surfaces can be maintained at a predetermined value by the above setting. As shown in FIGS. 2 and 6, hydrogen and oxygen supplied from the air supply port 14 are supplied to the gas passage 17.
To the top 18 of the reaction tube 1 from the gas passage outlet 17a.
And burning at the top 18 is also conceivable. In this case, the calorific value of the lower heater in the vertical direction is made larger than the calorific value of the heater 3 in the upper vertical direction, and the temperature of the processing gas passing through the gas passage 17 near the semiconductor wafer 4 is reduced.
7 is adjusted so as to be equal to the temperature of the processing gas in contact with the outside semiconductor wafer. Since the processing gas temperature rises due to combustion at the top portion 18, the heater 3 near the top portion 18 stops heating, lowers the supply gas temperature by radiating heat to the surroundings, and makes the processing gas temperature reaching the semiconductor wafer 4 uniform. maintain. FIGS. 3 and 4 show another embodiment of the present invention. The embodiment of FIG. 3 is different from the embodiment of FIG. 2 in that the air supply port 14 is omitted, the gas passage 17 is formed by a tube, and the processing chamber 22 is coiled at a position below the basket 5. It differs in that it is formed. According to this, the structure is simple. 4 is different from that of the embodiment shown in FIG. 2 in that a tube-shaped gas passage 17 is formed on the upper surface 14a of the air supply port 14 formed by an elongated double tube. Also in this case, the structure is simplified. 2, 3, and 4, the reaction tube 1 itself forms the processing chamber 22. According to the embodiment described above, a plurality of semiconductor wafers 4 are vertically stacked at intervals and arranged horizontally in a cylinder 22 forming a vertically long processing chamber. In the method of manufacturing a semiconductor device, the semiconductor wafer 4 is heated while heating the inside of the cylinder 22 and supplying the processing gas from the upper part of the semiconductor wafer 4 in the cylinder 22 and exhausting the processing gas from the lower part of the processing chamber 22. , The processing chamber 2
The process gas to be supplied to the heater 2 is guided from the lower portion to the upper portion, and the heater 3 causes the heater 3 to generate a non-uniform temperature due to a temperature difference toward the semiconductor wafer 4.
Preheating is performed so as to prevent generation of a downward flow, thereby preventing an uneven downward flow toward the semiconductor wafer 4 due to a density difference between the processing gas flowing into the processing chamber 22 and the processing gas in the processing chamber 22. Can be. Thus it is possible to uniformly heat-treated semiconductor wafer 4, the processing
The space above the semiconductor wafer in the chamber can be reduced
You. Further, the processing gas to be supplied to the processing chamber 22 is guided from the lower part to the upper part outside the processing chamber 22 and preheated by the heater 3, so that the processing gas is guided from the lower part to the upper part inside the processing chamber. In comparison, the processing chamber 22 is simplified, the semiconductor wafer 4 can be stored well, and the temperature in the processing chamber 22 can be reduced due to heat exchange with the processing gas flowing from the lower part to the upper part. Thus, it is possible to cope with an increase in the density of the integrated circuit. Since the heat equalizing tube 2 is provided between the processing chamber 22 and the heater 3 so as to cover the processing chamber 22, the heating in the processing chamber 22 can be performed more uniformly. Further, the inner tube 16 and the reaction tube 1 constituting the processing chamber 22 are formed.
And a gap between the inner cylinder 16 and the reaction tube 1 extends from the lower part to the upper part to form the processing gas supply port 24.
With the processing gas passage 17 communicating with the processing gas, the heating area in the processing gas passage 17 can be increased, and the processing gas can be more reliably preheated. Further, a cylindrical body is formed by a double cylinder of the inner tube 16 and the reaction tube 1 constituting the processing chamber 22, and the gap between the inner tube 16 and the reaction tube 1 is extended from the lower part to the upper part to supply the processing gas. By providing the processing gas passage 17 communicating with the port 24 and providing the air supply port 14 on the lower periphery of the reaction tube 1, the processing gas can be more reliably preheated and the wet oxidation processing can be performed easily. It can be performed with a simple configuration. Moreover, it leads to the top
The amount of heat generated by the heater below the processing gas
And heat in the cylinder near the bottom of the semiconductor wafer.
The temperature difference between the processing gases in contact with the inner and outer walls of the
This allows the entire semiconductor wafer to be uniformly oxidized and heat-treated.
can do. According to the method of manufacturing a semiconductor device of the present invention, it is possible to prevent a non-uniform downward flow due to a density difference between a processing gas flowing into a processing chamber and a processing gas in the processing chamber. The semiconductor wafer can be uniformly oxidized and heat-treated, and the space above the semiconductor wafer in the processing chamber can be reduced.
In addition, the processing chamber can be simplified, the semiconductor wafer can be stored easily, and the non-uniform temperature in the processing chamber due to heat exchange with the processing gas flowing from the lower part to the upper part can be reduced. Furthermore, uniform heating is achieved by heating through a soaking tube. Moreover, it leads to the top
The amount of heat generated by the heater below the processing gas
Heating the lower part of the semiconductor wafer
Eliminate the temperature difference between the processing gases in contact with the inner and outer walls of nearby cylinders.
This makes it possible to uniformly oxidize the entire semiconductor wafer.
Can be processed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a detailed vertical sectional view of a semiconductor wafer processing apparatus according to a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view of a main part of a semiconductor wafer processing apparatus according to a second embodiment of the present invention. FIG. 3 is a vertical sectional view of a main part of a semiconductor wafer processing apparatus according to a third embodiment of the present invention. FIG. 4 is a longitudinal sectional view of a main part of a semiconductor wafer processing apparatus according to a fourth embodiment of the present invention. FIG. 5 is a flow (schematic diagram) of a processing gas in each embodiment of FIGS. 1 and 2; FIG. 6 is a schematic flow diagram of a processing gas in the first embodiment of FIG. 1; FIG. 7 is a schematic flow diagram of a processing gas in a conventional semiconductor wafer processing apparatus. [Description of Symbols] 1 ... reaction tube (cylindrical body), 2 ... heat equalizing tube, 3 ... heater, 4 ... semiconductor wafer, 5 ... basket, 6 ... basket stage, 7 ... loading mechanism, 8 ... processing gas supply port, 9 ...
Cap, 11: Firebrick, 12: Base, 13: Heat insulating material, 14: Air supply port, 16: Inner cylinder, 17: Gas passage, 18: Top, 19: Gap, 20: Transport port, 21: Bottom part, 22: processing chamber, 24: processing gas supply port.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Tetsuya Takagaki               1450 Josui Honcho, Kodaira City, Tokyo Stock Association               Hitachi, Ltd. Musashi Factory                (56) References JP-A-55-118631 (JP, A)                 JP-A-56-91417 (JP, A)                 JP-A-58-108735 (JP, A)                 Actual opening 56-21439 (JP, U)

Claims (1)

(57) [Claims] A plurality of semiconductor wafers are horizontally arranged in a cylinder forming a vertically elongated processing chamber, and are arranged in a vertical direction with an interval,
A method for manufacturing a semiconductor device, comprising: heating the inside of a cylinder with a heater; and oxidizing and heat-treating a semiconductor wafer that supplies a processing gas from an upper part of the semiconductor wafer in the cylinder and exhausts a processing gas from a lower part of the cylinder . The processing gas to be supplied into the cylinder is located outside the cylinder and inside the heater at a lower portion.
And heat it in advance with the heater ,
The processing gas guided to the upper part is below the semiconductor wafer.
And heating the heater by increasing the amount of heat generated by the heater .