JP2004349479A - Heat treatment device for processing wafers piece by piece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment device processing wafers piece by piece capable of quickly and uniformly heating a matter to be processed while mitigating the variety of temperature in a heat ray supplying means which is generated in connection with rapid heating, and capable of effecting the heating more correctly. <P>SOLUTION: The heat treatment device processing wafers piece by piece 1 is provided with a treatment chamber 3 and the heat ray supplying means 4 arranged at the outer wall surface 3a side of the treatment chamber 3. In this case, the treatment chamber 3 is formed of a heat ray non-transmittable material to heat the matter to be processed (semiconductor wafer) W received in the treatment chamber 3 through atmosphere heating. An opaque quartz, for example, is employed as the heat ray non-transmittable material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a single-wafer heat treatment apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in the manufacture of a semiconductor device, a display device, or the like, a flat object to be processed such as a semiconductor wafer is subjected to heat treatment such as oxidation, diffusion, film formation (CVD: Chemical Vapor Deposition, etc.), and annealing. Various heat treatment apparatuses are used. As this type of heat treatment apparatus, there are known a batch heat treatment apparatus for heat treating a plurality of plate-shaped workpieces at once, and a single-wafer heat treatment apparatus for heat treating one sheet at a time. Among these, the single-wafer heat treatment apparatus can be relatively easily used for heat treatment that requires rapid temperature rise and fall and uniform heat treatment within the semiconductor wafer surface as compared with the batch type heat treatment apparatus. It is getting.
[0003]
Single-wafer heat treatment apparatuses can be classified into induction heating type, resistance heating type, and lamp heating type according to the heating means (hot-wire supply means). Uniformization and improvement of the temperature rise / fall rate are major technical issues. That is, the uniformization of the in-plane temperature is important not only in the process but also in the process of raising and lowering the temperature, and is a very important factor that governs the quality and yield of the semiconductor wafer. On the other hand, the improvement of the temperature rise / fall rate is a very important factor for achieving an improvement in throughput and a reduction in thermal budget. However, in general, when the speed of temperature rise / fall is increased, variation in the in-plane temperature tends to occur. In other words, the uniformity of the in-plane temperature and the improvement of the temperature rise / fall rate are in a trade-off relationship, and it is very difficult to achieve both improvement of the quality and yield of the semiconductor wafer, and improvement of the throughput and reduction of the thermal budget.
[0004]
In such a case, in a conventional single-wafer heat treatment apparatus, transparent quartz is often used as a material of a chamber for accommodating a flat object to be processed (for example, see Patent Document 1). This is because the light transmittance of the transparent quartz (light transmittance at a near-infrared wavelength of 1 to 5 μm which greatly contributes to heating) is as large as 90% or more, so that the heat rays from the heat ray supply means are almost absorbed by the chamber itself. Without being supplied directly to the workpiece.
[0005]
[Patent Document 1]
JP-A-11-224879 (page 4)
[0006]
[Problems to be solved by the invention]
However, with the recent increase in the size of an object to be processed such as a semiconductor wafer (for example, a semiconductor wafer having a diameter of 300 mm or more) and a further increase in the demand for improving the throughput and reducing the thermal budget, the uniformization of the in-plane temperature and the improvement of the rate of temperature rise and fall have been considered. Demands have become even higher, and direct heating using a chamber made of transparent quartz has become more difficult to meet the demands.
Specifically, when a heat ray is directly supplied to an object to be processed, (1) the temperature unevenness of the heat ray supply means generated due to rapid heating directly affects the uniformity of the in-plane temperature of the object to be processed. 2) Since the temperature of the object to be processed rises faster than the temperature of the atmosphere in the processing chamber, the temperature of the atmosphere in the processing chamber is measured with a thermocouple disposed at a predetermined position in the processing chamber, and the heating control is performed based on the measured data. However, there is a problem that overheating of the object to be processed is apt to occur, and it is very difficult to accurately control the heating of the object to be processed.
[0007]
The present invention has been made in view of such circumstances, and can mitigate the temperature unevenness of the hot-wire supply means generated due to rapid heating, and can quickly and uniformly heat an object to be processed. It is an object of the present invention to provide a single-wafer heat treatment apparatus that can be performed accurately.
[0008]
[Means for Solving the Problems]
The single-wafer heat treatment apparatus of the present invention is arranged on a processing chamber in which a flat object to be processed is accommodated one by one, and is disposed on an outer wall surface side of the processing chamber, and supplies a heat ray toward the outer wall surface of the processing chamber. A heat treatment apparatus, wherein the processing chamber is formed of a heat-impermeable material, and the object to be processed accommodated in the processing chamber is heated in an atmosphere. It is characterized by:
[0009]
According to the above configuration, when a heat ray is supplied from the heat ray supply means, the processing chamber itself made of a heat ray impermeable material absorbs the heat ray and generates heat. Then, the ambient temperature in the processing chamber is increased by the re-radiation of the processing chamber, and the object to be processed can be heat-treated with the re-radiation and convection heat transfer by the atmosphere. For this reason, it is possible to suppress the temperature unevenness of the heat ray supply means accompanying the rapid heating from directly leading to the non-uniformity of the in-plane temperature of the object to be processed, and as a result, the object to be processed is rapidly and uniformly heated. Can be. Further, according to the induction heating apparatus of the present invention, even if the temperature of the atmosphere in the processing chamber is measured by the temperature sensor disposed at a predetermined position in the processing chamber, and the heating control is performed based on the measured data, the temperature of the atmosphere is not increased. Is faster than the temperature rise of the object to be processed, so that excessive heating of the object to be processed can be suppressed, and more accurate heating control of the object to be processed can be performed.
[0010]
Here, in the present invention, the "heat ray supply means" refers to a means for supplying a heat ray containing a near-infrared wavelength (1 to 5 μm) which greatly contributes to heating, and is a known type such as an induction heating type, a resistance heating type, and a lamp heating type. Heating means.
The term “heat-ray opaque material” refers to various materials that have a light transmittance at a near-infrared wavelength (1 to 5 μm) that greatly contributes to heating, as compared with transparent quartz. Above all, a material having a light transmittance of 15% or less is preferable.
[0011]
In the above-mentioned single-wafer heat treatment apparatus, it is preferable that the heat-impermeable material is opaque quartz. In this case, it is possible to surely alleviate the temperature unevenness of the heat ray supply means caused by the rapid heating, to rapidly and uniformly heat the object to be processed, and to perform the heating more accurately.
[0012]
In the above-described single-wafer heat treatment apparatus, it is preferable that the hot-wire supply unit includes an induction heating coil and a heating element that is induction-heated by the induction heating coil. In this case, there is an advantage that the temperature rise / fall rate can be increased as compared with the resistance heating type.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a front sectional view showing a configuration of a single-wafer heat treatment apparatus according to an embodiment of the present invention, and FIG. 1B is a side sectional view thereof. The single-wafer heat treatment apparatus 1 according to the present embodiment is used, for example, for heat treatment (oxidation, diffusion, film formation, annealing, etc.) of a disc-shaped semiconductor wafer W as an object to be processed, and accommodates one semiconductor wafer W at a time. Processing chamber 3, heat-ray supply means (heating means) 4 which is provided separately on the outer wall 3 a side of processing chamber 3, and outer wall 3 a of processing chamber 3 and inner wall 4 a of heat-ray supply means 4 And a cooling medium flow passage 5 provided between them.
[0014]
The processing chamber 3 has a substantially flat cylindrical shape as a whole, and has an opening 3b at one end side (left side in FIG. 1B) for loading and unloading the semiconductor wafer W, and the other end side (FIG. The b) has a small-diameter vent 3c on the right side for gas introduction and degassing. A support 3d is provided inside the processing chamber 3 so that the semiconductor wafer W can be placed thereon. Although not shown, a thermocouple as a temperature sensor is provided at a predetermined position in the processing chamber 3 to measure the ambient temperature. Similarly, although not shown, a cover, a valve, and the like are appropriately provided in the opening 3b and the vent 3c so that the processing chamber 3 can be a closed space.
[0015]
The processing chamber 3 is entirely formed of opaque quartz as a heat-impermeable material. Opaque quartz is formed by melting high-quality silica stone, has a low content of impurities such as alkali metals and copper, and has many microbubbles as a whole. Opaque quartz in which a large number of microbubbles are distributed from the surface to the inside absorbs about 90% of light having a near infrared wavelength (1 to 5 μm). For this reason, the temperature of the processing chamber 3 itself becomes high due to the heat rays supplied from the heat ray supply means 4.
[0016]
The heat ray supply means 4 is, for example, of an induction heating type, is wound around the outer wall surface of the processing chamber 3, and has a predetermined distance in the axial direction (left and right direction in FIG. 1B) inside the iron core 4b. An induction heating coil 4c, a heating element 4d formed of a conductive material having a large heat conductivity and a high emissivity, such as graphite, having a substantially flat cylindrical shape and heated by the induction heating coil 4c; A substantially flat cylindrical heat insulating material 4e interposed between the induction heating coil 4c and the heating element 4d to protect the induction heating coil 4c from radiant heat of the heating element 4d, and a high frequency connected to the induction heating coil 4c. And a current supply means (not shown). The high-frequency current supply means includes a high-frequency (approximately 30 to 50 kHz) AC power supply, and is configured to perform output control to a predetermined position of the induction heating coils 4c arranged in the axial direction.
[0017]
The cooling medium flow passage 5 extends between the outer wall surface 3a of the processing chamber 3 and the inner wall surface 4a of the heating means 4 along the longitudinal direction of the processing chamber 3 (the left-right direction in FIG. 1B). And is formed in a flat annular shape along the circumferential direction. Then, a cooling medium such as a cooling gas supplied from a cooling medium supply unit (not shown) flows to cool the heated body 4 d, the processing chamber 3 itself, and further the atmosphere in the processing chamber 3. Have been.
[0018]
The heat treatment of the semiconductor wafer W by the single-wafer heat treatment apparatus 1 having the above configuration is performed, for example, as follows. That is, when a high-frequency current is supplied to the induction heating coil 4c by a high-frequency current supply unit (not shown), a magnetic flux (lines of magnetic force) is generated from the induction heating coil 4c. When the magnetic flux penetrates through the heating element 4d, an eddy current is generated in the heating element 4d. Joule heat is generated by the eddy current and the electric resistance of the heating element 4d itself, and the heating element 4d generates heat. Thereafter, the heat rays from the heating element 4d are supplied toward the outer wall surface 3a of the processing chamber 3, and the processing chamber 3 made of opaque quartz absorbs the heat rays while hardly transmitting the heat rays. Rises. When the temperature of the processing chamber 3 itself increases, the temperature of the atmosphere in the processing chamber 3 increases due to the re-radiation of the processing chamber 3, and the semiconductor wafer W is heated together with the re-radiation and convective heat transfer by the atmosphere (atmospheric heating). Is performed. Subsequently, the cooling is performed, for example, as follows. That is, when a cooling gas as a cooling medium is supplied to the cooling medium flow passage 5 by a cooling medium supply unit (not shown), the cooling gas flows through the flow passage 5 and removes heat of the heating element 4 d and the processing chamber 3 itself. Take away. Thereby, the temperature of the heating body 4d and the temperature of the processing chamber 3 itself decrease. When the temperature of the processing chamber 3 becomes lower than the ambient temperature in the processing chamber 3, the processing chamber 3 itself removes heat from the atmosphere in the processing chamber 3 in addition to cooling the semiconductor wafer W by radiant heat transfer. Cooling is performed by lowering the ambient temperature, and further, the atmosphere removes heat from the semiconductor wafer W.
[0019]
In the single-wafer heat treatment apparatus 1 according to the present embodiment configured as described above, the processing chamber 3 itself absorbs heat rays to generate heat, and the temperature of the atmosphere in the processing chamber 3 is reduced by re-radiation from the heated processing chamber 3. Since the heat treatment of the semiconductor wafer W accompanied by convection heat transfer due to the atmosphere as well as the re-radiation can be performed, the temperature unevenness of the heat ray supplying means 4 caused by the rapid heating can make the in-plane temperature of the semiconductor wafer W non-uniform. Can be alleviated. Further, even if the heating control is performed based on the measurement data of the ambient temperature from a thermocouple as a temperature sensor disposed at a predetermined position in the processing chamber 3, the heating is performed after the ambient temperature in the processing chamber 3 is increased. Since the heat treatment of the processed object is performed, the semiconductor wafer W is not excessively heated. Therefore, as compared with the conventional single-wafer heat treatment apparatus, the quality and yield of the large-diameter semiconductor wafer W can be improved, and the throughput can be improved and the thermal budget can be reduced. In addition, in the above-described single-wafer heat treatment apparatus, when performing heating control by performing output control by zoning or the like to the induction heating coil 4c in the column direction of the induction heating coil 4c (the left-right direction in FIG. 1B). In the processing chamber made of transparent quartz described above, it was very difficult to eliminate the temperature unevenness in the direction perpendicular to the column direction (the vertical direction in FIG. 1B), but the processing chamber made of a heat-impermeable material was used. The configuration in which the object to be processed is heated in the atmosphere has an advantage that temperature unevenness in a direction perpendicular to the column direction can be largely eliminated.
[0020]
Note that the present invention is not limited to the embodiment described above. For example, silicon carbide (SiC) may be used as the heat-impermeable material. The object 2 is not limited to a semiconductor wafer, and may be any shape and material as long as it is flat. A typical example may include an insulating substrate such as a glass substrate and various thin films formed on the surface thereof. Further, the processing chamber 3 may have a rectangular shape. Further, the heat ray supply means (heating means) 4 may be of a resistance heating type using a resistance heater or a lamp heating type using a halogen lamp, for example. Note that in the case where rapid heating is performed by a resistance heating method, the heating can be performed by, for example, introducing an object to be processed into a preheated processing chamber.
[0021]
【The invention's effect】
As described above, the single-wafer heat treatment apparatus of the present invention includes a processing chamber formed of a heat-impermeable material, and is configured to heat an object to be processed accommodated in this processing chamber in an atmosphere. The unevenness in the temperature of the heat ray supply means caused by the rapid heating can be reduced, and the object can be heated quickly and uniformly, and the heating can be performed more accurately. Therefore, as compared with the conventional single-wafer heat treatment apparatus, it is possible to improve the quality and yield of an object to be processed such as a semiconductor wafer having a large diameter, to improve the throughput, and to reduce the thermal budget.
[Brief description of the drawings]
FIG. 1A is a front sectional view of a single-wafer heat treatment apparatus according to an embodiment of the present invention, and FIG. 1B is a side sectional view thereof.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Single-wafer heat treatment apparatus 3 Processing chamber 3a Outer wall surface 4 Heat ray supply means 4c Induction heating coil 4d Heating body W Semiconductor wafer (workpiece)

Claims (3)

A processing chamber in which flat objects to be processed are accommodated one by one, and a hot-wire supply means arranged on the outer wall surface side of the processing chamber and supplying a hot wire toward the outer wall surface of the processing chamber A leaf-type heat treatment apparatus,
The single-wafer heat treatment apparatus, wherein the processing chamber is formed of a heat-ray-impermeable material, and the processing target housed in the processing chamber is configured to be heated in an atmosphere. The single-wafer heat treatment apparatus according to claim 1, wherein the heat-opaque material is opaque quartz. 3. The single-wafer heat treatment apparatus according to claim 1, wherein the heating wire supply unit includes an induction heating coil and a heating body that is induction-heated by the induction heating coil. 4.

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