JP2006210641A - Apparatus for manufacturing semiconductor, heat treatment apparatus, method of manufacturing semiconductor, and heat treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing a semiconductor and a heat treatment apparatus capable of shortening treatment time, by improving the efficiency of temperature rise and temperature fall while miniaturizing the apparatuses. <P>SOLUTION: The apparatus for manufacturing the semiconductor comprises a process tube 10 having conductive properties and storing a semiconductor; a cylindrical heat insulation/cooling structure 20 for forming a space 23 for covering an outer circumference of the process tube 10 for heat insulation and cooling of the tube 10; an induction heating coil 30 disposed on an outer circumference of the heat insulation/cooling structure 20; an induction heating control circuit 40 for driving the induction heating coil 30; and a fluid introduction passage 71 to the space 23 of the heat insulation/cooling structure 20, and fluid discharge passages 72, 73 from the space 23. The space 23 is switchable to a vacuum state and to a passage state of a cooling medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductor manufacturing apparatus that performs processing related to heat treatment of a semiconductor such as oxidation and diffusion of a wafer, a heat treatment apparatus for performing heat treatment of other materials, and a semiconductor manufacturing method and a heat treatment method using these apparatuses.

In a conventional heat treatment apparatus such as a diffusion furnace or a CVD furnace, a large apparatus that can simultaneously process 100 wafers is the mainstream. These conventional devices process large quantities of wafers at the same time and have high throughput, but their heat capacity is overwhelmingly large, so it takes time to raise and lower the temperature, and generally several tens of minutes to reach a stable temperature range. Takes more than an hour.
In addition, if the heat insulation of the reaction tube is performed to increase the energy efficiency at the time of temperature increase, the temperature decrease time becomes long, and if the temperature decrease time is shortened without performing heat insulation, the heat release at the time of temperature increase and constant temperature is large, In addition to poor energy efficiency, there was a problem that the heat load on the clean room also increased.
In order to solve such a problem, a heat treatment apparatus has been proposed in which a heat insulating layer and an air passage are provided to enable air cooling, and heating is performed from the outside using induction heating (for example, Patent Document 1).
JP 2003-174262 A

However, the structure in which the heat insulation layer and the air passage are provided respectively is a double structure of the heat insulation layer and the air cooling layer, the distance from the induction coil becomes long, the heating efficiency is deteriorated, and the apparatus is enlarged. Cause serious problems.
Accordingly, the present invention provides a semiconductor manufacturing apparatus, a heat treatment apparatus, a semiconductor manufacturing method, and a heat treatment method capable of reducing the processing time by improving the temperature raising and lowering efficiency while reducing the size of the apparatus. It is intended.

The semiconductor manufacturing apparatus of the present invention includes a process tube having conductivity for housing a semiconductor, a heat insulating and cooling structure that covers an outer periphery of the process tube and forms a space for heat insulation and cooling of the tube, An induction heating coil disposed on the outer periphery of the heat insulating and cooling structure; a drive means for the induction heating coil; a fluid introduction path to the space; and a fluid discharge path from the space; It can be switched to the passing state of the cooling medium. As the cooling medium, air, water, or a medium that functions to take heat away by vaporization can be used.
According to this, when the temperature is raised, the space of the heat insulating and cooling structure is in a vacuum state to have heat insulation, and when the temperature is lowered, the cooling rate can be increased by flowing the cooling medium in the space. The time for heating and cooling in the heat treatment of the semiconductor in the process tube is shortened. In addition, since a common structure space is used for heat insulation and cooling in that case, the semiconductor manufacturing apparatus can be downsized.

The heat insulating and cooling structure can be constituted by a cylindrical body having an inner wall fitted to the outer periphery of the process tube and an outer wall facing the inner wall.
In that case, it is preferable that a plurality of fins that scatter a flow of fluid passing through the space is arranged in the space. By doing so, the cooling medium flowing in the space is diffused in the space, so that the cooling efficiency is improved.
Moreover, it is preferable that the said fin protrudes from the said inner wall of the said heat insulation and cooling structure. By doing so, when the process tube is cooled, the fin also acts as a heat radiating fin, and the cooling efficiency is improved.
In addition, you may comprise the said heat insulation and cooling structure from the pipe material wound around the outer periphery of the said process tube.
In the above apparatus, it is preferable that the fluid introduction channel includes a valve that opens and closes the channel, and that the fluid discharge channel can communicate with a vacuum pump. Thereby, the space of the heat insulating and cooling structure can be easily evacuated or the cooling medium can be easily passed through the space.
Further, it is preferable that the fluid introduction channel and the fluid discharge channel communicate with the space at a position separated from a front end side and a rear end side of the process tube. As a result, the cooling medium easily spreads over the entire space of the heat insulating and cooling structure, so that the cooling efficiency is improved.

  Further, the process tube may be either a tube in which a conductor is coated around a quartz tube or a tube in which the entire tube is made of a conductor. In the former, since the conductor and the object to be heat-treated are isolated, the influence of contamination by metal or the like from the conductor can be reduced, and the latter has the advantage that the heat capacity is small and the efficiency of temperature rise and fall is good.

  The semiconductor manufacturing method of the present invention uses the semiconductor manufacturing apparatus described above, and the space of the heat insulating and cooling structure is evacuated when the temperature is raised, and the cooling medium is allowed to flow through the space when the temperature is lowered.

The heat treatment apparatus of the present invention is a process tube having conductivity for housing the object to be heat treated, a heat insulating and cooling structure that covers the outer periphery of the process tube and forms a space for heat insulation and cooling of the tube, An induction heating coil disposed on the outer periphery of the heat insulating and cooling structure; a drive means for the induction heating coil; a fluid introduction path to the space; and a fluid discharge path from the space; And switching between the cooling medium passing state.
According to this, for the process tube, when the temperature is raised, the space of the heat insulating and cooling structure is in a vacuum state so as to have heat insulation properties, and when the temperature is lowered, the cooling medium is allowed to flow in the space so that the cooling rate is increased. Since it can speed up, the time of temperature rising / falling with respect to the to-be-processed object in a process tube is shortened. In addition, since the structure space common to the heat insulation and cooling in that case is used, the heat treatment apparatus can be downsized.

  The heat treatment method of the present invention uses the heat treatment apparatus described above, wherein the space of the heat insulating and cooling structure is evacuated when the temperature is raised, and the cooling medium is allowed to flow through the space when the temperature is lowered.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an overall configuration of a semiconductor manufacturing apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a cross section along a radial direction of a process tube portion of the semiconductor manufacturing apparatus of FIG.

  The semiconductor manufacturing apparatus 1 includes a cylindrical process tube 10 in which a semiconductor wafer or other object to be heat-treated is accommodated, a heat insulating and cooling structure 20 that covers the outer periphery of the process tube 10, and a longitudinal length of the outer periphery of the heat insulating and cooling structure 20. An induction heating coil 30 wound in the direction, an induction heating control circuit 40 as an induction heating coil driving means for controlling power supply to the induction heating coil 30, and a support base 50 for holding the object to be heat treated in the process tube 10. It is equipped with.

  In the process tube 10, the tube body is usually made of a heat-resistant member that can withstand a temperature of about 1000 ° C., here, quartz 11, and the outer surface of the quartz tube 10 is heated by an induction heating coil 30. A conductor 12 having high resistance is attached so as to be in close contact with a film or the like. These conductors include tungsten, molybdenum, tantalum, nickel, iron / chromium alloys, nickel / chromium alloys, silicon carbide, graphite and the like. In addition, you may comprise the whole process tube 10 from the above conductors.

As can be seen from FIG. 2, the heat insulating and cooling structure 20 is formed of a cylindrical body having an inner wall 21 fitted to the outer periphery of the process tube 10 and an outer wall 22 facing the inner wall 21. . A space 23 is formed between the inner wall 21 and the outer wall 22. The inner wall of the heat insulating and cooling structure 20 is attached in close contact with the outer periphery in the longitudinal direction of the process tube 10, and the space 23 is used as heat insulating or cooling space for the process tube 10. Therefore, it is preferable that the heat insulating and cooling structure 20 is made of alumina (Al ₂ O ₃ ), silicon carbide (SiC) or the like having excellent heat resistance.
In addition, a plurality of fins 24 are projected from the inner wall 21 of the heat insulating and cooling structure 20 in the space 23, and the fin 24 is scattered from the fluid flowing in the space 23 and transmitted from the process tube 10 when the temperature is lowered. It is preferable to have a function of radiating heat.

  The induction heating coil 30 is driven and controlled by the induction heating control circuit 40 and is supplied with an alternating current, so that the process tube 10 generates heat using the conductor 12 of the process tube 10. Therefore, from the viewpoint of heat generation efficiency, it is preferable that the entire process tube 10 is made of a conductor.

  The induction heating control circuit 40 is a circuit having a function of taking AC power from a commercial power source and converting it into a high-frequency AC current and supplying the high-frequency AC current to the induction heating coil 30 in a necessary amount when necessary. It is. The induction heating control circuit 40 may have an arbitrary configuration. For example, the induction heating control circuit 40 includes an element for turning on / off the circuit 40, a rectifier circuit, a high-frequency inverter circuit, and the like. In addition, the power supply circuit of the heating unit disclosed in Patent Document 1 introduced as a prior document can be used.

  The support base 50 for the object to be heat-treated is configured to hold a plurality of objects to be heat-treated such as semiconductor wafers, and the heat-treated object holding part can be freely inserted into and removed from the process tube 10.

  The process tube 10 is provided with a process gas input pipe 61 for supplying process gas into the process tube 10 at one end, and a process gas discharge pipe 62 for discharging process gas at the other end. ing.

  The heat insulating and cooling structure 20 is provided with a fluid introduction path 71 and fluid discharge paths 72 and 73 communicating with the space 23. The fluid introduction channel 71 and the fluid discharge channels 72 and 73 are preferably communicated with the space 23 at positions separated from the front end side and the rear end side of the process tube 10. This is because the cooling medium introduced from the fluid introduction passage 71 and discharged from the fluid discharge passages 72 and 73 spreads throughout the space 23 well.

  A first valve 81 is provided in the fluid introduction path 71 so that the flow path can be opened and closed. The fluid discharge path 72 is connected to the vacuum pump 90, and the fluid discharge path 72 is provided with a second valve 82 that opens and closes communication with the vacuum pump 90. The fluid discharge path 73 is branched from the fluid discharge path 72 and is used for heat exhaust or cooling medium recovery. The fluid discharge path 73 is also provided with a third valve 83 that opens and closes the flow path.

  Next, a usage example of the semiconductor manufacturing apparatus 1 will be described with reference to a flowchart showing an example of the heat treatment in FIG. First, a support base 50 holding an object to be heat treated, for example, a semiconductor wafer, is inserted into the process tube 10 and fixed (S1). Subsequently, the first valve 81 and the third valve 83 are closed, the second valve 82 is opened, and the space 23 of the heat insulating and cooling structure 20 is brought into a vacuum state lower than the atmospheric pressure by using the vacuum pump 90 (S2). . Subsequently, an electric current is supplied to the induction heating coil 30 using the induction heating control circuit 40, the conductor 12 is heated, the temperature in the process tube 10 is raised to a required temperature, and the temperature is maintained for a required time. (S3). In step S3, when the temperature in the process tube 10 reaches a predetermined temperature corresponding to the heat treatment, a required amount of process gas corresponding to the processing content is charged into the process tube 10 from the process gas charging pipe 61. The process gas is discharged from the process gas discharge pipe 62 after the process time is over.

  Then, the current supply to the induction heating coil 30 is stopped when a predetermined time of the high temperature processing for the semiconductor wafer has elapsed. Thereafter, the second valve 82 is closed, the first valve 81 and the third valve 83 are opened to release the vacuum state of the space 23, and the vacuum insulation of the space 23 is released (S4). Subsequently, air, water or other cooling medium is introduced from the fluid introduction path 71 into the space 23 of the heat insulating and cooling structure 20, and is discharged from the fluid discharge paths 72 and 73 through the entire space 23 (S5). ). It is preferable that the discharged cooling medium is cooled again and reused. And when the temperature in the process tube 10 falls to a predetermined temperature, the heat treatment of the semiconductor wafer is completed by removing the support base 50 from the process tube 10 (S6).

In addition, as a process gas in the above, the following are mentioned according to the process, for example. In the silicon thermal oxide film formation process, oxygen or hydrogen + oxygen-reacted water vapor, in the CVD silicon oxide film formation process, tetraethoxysilane (TEOS) + oxygen, in the CVD silicon nitride film formation process Dichlorosilane (SiH ₂ Cl ₂ ) + ammonia (NH ₃ ), monosilane (SiH ₄ ) in the CVD polysilicon film formation process. During the CVD film formation, the inside of the process tube 10 is often decompressed.
In addition to air and water, the cooling medium in the above can use a medium that acts to remove heat by vaporization, such as alternative CFCs (HFCs, HCFCs).

  The above-described semiconductor manufacturing apparatus is used to increase the thermal efficiency by making the space 23 of the heat insulation / cooling structure 20 a vacuum insulation when the temperature of the object to be heat-treated is maintained at a high temperature to a high temperature. By flowing the cooling medium through the 20 spaces 23, the cooling rate is improved and the process time can be reduced. Further, since energy efficiency is improved, the heat load on the clean room can be reduced. In addition, since the present apparatus has a structure in which these functions of heat insulation and cooling are performed using one heat insulating and cooling structure 20, the apparatus can be reduced in size.

  By the way, although the example using the cylindrical heat insulation and cooling structure 20 having the inner wall and the outer wall is shown in FIG. 1, it may be a heat insulation and cooling structure 20A of the pipe as shown in FIG. it can. The heat insulating and cooling structure 20A is composed of a tube material such as a tube wound a plurality of times along the longitudinal direction of the outer periphery of the process tube 10. In this case, the inner space of the tube material such as a tube is used for heat insulation and cooling. Therefore, from the viewpoint of improving the heat insulation and cooling efficiency of the process tube 10, it is preferable to form the heat insulation and cooling structure 20 </ b> A by winding the tube material so as to be as close as possible in the longitudinal direction of the process tube 10. Even in this case, one end of the wound pipe is communicated with the fluid introduction path 71, and the other end of the tubing is communicated with the fluid discharge paths 72 and 73. Even if the operation as shown in FIG. 3 is performed using the heat insulating and cooling structure 20A of the tubular material, the heat insulating and cooling effects substantially the same as those when the tubular heat insulating and cooling structure 20 is used can be obtained. Can do.

  The portion corresponding to the heat treatment furnace in the apparatus of the present invention includes a process tube, a heat insulating and cooling structure that covers the outer periphery of the process tube and forms a space for heat insulation and cooling of the tube, and a heat insulating and cooling structure. What is necessary is just a structure provided with the induction heating coil arrange | positioned on the outer periphery. Therefore, rather than wrapping the tube material used in FIG. 4 around the process tube, prepare a plurality of such tube materials, arrange them in parallel with the tube axis direction of the process tube, and set the entire outer periphery along the axial direction of the process tube. It is possible to cover and insulate and cool the process tube using the internal space of these pipes. In this way, the flow of the cooling medium becomes particularly good, so that the cooling efficiency can be further improved.

The semiconductor manufacturing apparatus and manufacturing method described in the above embodiment can also be applied to a heat processing apparatus and a heat processing method for an object to be heat processed other than a semiconductor.
Further, the application target of the apparatus of the present invention includes annealing, diffusion, thermal oxidation, thermal CVD and the like of a heat-treated object including a semiconductor.

The schematic diagram which shows the whole structure of the semiconductor manufacturing apparatus which concerns on embodiment of this invention. The schematic diagram which shows the cross section along the radial direction of the process tube part of the apparatus of FIG. The flowchart which shows an example of the heat processing using the apparatus of FIG. The schematic diagram which shows the structure of the semiconductor manufacturing apparatus which concerns on another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Semiconductor manufacturing apparatus (heat processing apparatus), 10 ... Process tube, 11 ... Quartz, 12 ... Conductor, 20 ... Heat insulation and cooling structure of cylindrical body, 20A ... Heat insulation and cooling structure of pipe material, 21 ... Inner wall , 22 ... outer wall, 23 ... space, 24 ... fin, 30 ... induction heating coil, 40 ... induction heating control circuit, 50 ... support base, 61 ... process gas input pipe, 62 ... process gas discharge pipe, 71 ... fluid introduction Path, 72, 73 ... fluid discharge path, 81 ... first valve, 82 ... second valve, 83 ... third valve, 90 ... vacuum pump.

Claims (14)

A conductive process tube for housing a semiconductor, a heat insulating and cooling structure covering the outer periphery of the process tube to form a space for heat insulation and cooling of the tube, and an outer periphery of the heat insulating and cooling structure; An induction heating coil disposed; drive means for the induction heating coil; a fluid introduction path to the space; and a fluid discharge path from the space;
A semiconductor manufacturing apparatus, wherein the space can be switched between a vacuum state and a cooling medium passage state.   The said heat insulation and cooling structure consists of a cylindrical body which has an inner wall fitted to the outer periphery of the said process tube, and an outer wall facing this inner wall. Semiconductor manufacturing equipment.   The semiconductor manufacturing apparatus according to claim 2, wherein a plurality of fins that scatter a flow of fluid passing through the space are arranged in the space.   The semiconductor manufacturing apparatus according to claim 3, wherein the fin protrudes from the inner wall of the heat insulating and cooling structure.   The semiconductor manufacturing apparatus according to claim 1, wherein the heat insulating and cooling structure is made of a tube material wound around an outer periphery of the process tube.   6. The semiconductor manufacturing apparatus according to claim 1, wherein a valve for opening and closing the flow path is provided in the fluid introduction flow path, and the fluid discharge path is capable of communicating with a vacuum pump.   The semiconductor manufacturing apparatus according to claim 6, wherein the fluid introduction channel and the fluid discharge channel communicate with the space at a position separated from a front end side and a rear end side of the process tube.   8. The semiconductor manufacturing apparatus according to claim 1, wherein the process tube is formed by coating a conductor around a quartz tube.   The semiconductor manufacturing apparatus according to claim 1, wherein the entire tube of the process tube is made of a conductor.   The semiconductor manufacturing apparatus according to claim 1, wherein the cooling medium is either air or water.   The semiconductor manufacturing apparatus according to claim 1, wherein the cooling medium is a medium that has a function of removing heat by vaporization.   12. A semiconductor using the semiconductor manufacturing apparatus according to claim 1, wherein the space of the heat insulating and cooling structure is in a vacuum state when the temperature is raised, and a cooling medium is allowed to flow in the space when the temperature is lowered. Production method. An electrically conductive process tube for housing an object to be heat-treated, an insulation and cooling structure that covers an outer periphery of the process tube and forms a space for heat insulation and cooling of the tube; and An induction heating coil disposed on the outer periphery, driving means for the induction heating coil, a fluid introduction path to the space, and a fluid discharge path from the space,
A heat treatment apparatus characterized in that the space can be switched between a vacuum state and a cooling medium passage state. A heat treatment method using the heat treatment apparatus according to claim 13, wherein the space of the heat insulating and cooling structure is in a vacuum state when the temperature is raised, and a cooling medium is flowed into the space when the temperature is lowered.

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