WO2001082349A1

WO2001082349A1 - Thermal processing system and thermal processing method

Info

Publication number: WO2001082349A1
Application number: PCT/JP2001/003280
Authority: WO
Inventors: Takashi Shigeoka; Takeshi Sakuma; Yicheng Li
Original assignee: Tokyo Electron Limited
Priority date: 2000-04-20
Filing date: 2001-04-17
Publication date: 2001-11-01
Also published as: TWI222140B

Abstract

A thermal processing system performs predetermined thermal processing on an approximately circular to-be-processed object, by applying radiant heat to the to-be-processed object by means of a heating lamp system. The heating lamp system comprises a plurality of lamps disposed concentrically so as to correspond to the to-be-processed object.

Description

DESCRIPTION

THERMAL PROCESSING SYSTEM AND THERMAL PROCESSING METHOD

TECHNICAL FIELD

The present invention relates to a system and a method for performing thermal processing, such as annealing processing, CVD (Chemical Vapor Deposition) or the like, on a to-be-processed object, such as a semiconductor wafer, for example, by using a heating lamp system.

BACKGROUND ART

In general, in order to manufacture a semiconductor integrated circuit, various thermal processes such as a deposition process, an annealing process, an oxidization and diffusion process, a spattering process, an etching process, a nitriding process and so forth are performed several times repeatedly on a silicon substrate such as a semiconductor wafer .

In this case, in order to maintain electric characteristics of the integrated circuit and throughput of the products to high level , the above-mentioned various thermal processes should be performed on the entire surface of the wafer more uniformly. For this purpose, because the progress of the thermal process remarkably depends on the temperature of the wafer, the temperature of the wafer should be uniform throughout the entire surface thereof at high accuracy.

In order to maintain the temperature of the wafer uniform throughout the entire surface thereof, various methods are known. For example, in one method used in a single-wafer-type thermal processing system, a placement table on which a semiconductor wafer is placed is rotated so that occurrence of unevenness in temperature is avoided. In another method, irradiated heat generated by heating lamps which can heat the wafer rapidly are controlled selectively for respective zones of the wafer.

FIGS. 1 and 2 show one example of a thermal processing system in the related art. FIG. 1 shows a general configuration of the thermal processing system, and FIG. 2 shows a plan view illustrating an arrangement of heating lamps of the thermal processing system. As shown in FIG. 1, in a processing chamber 2, a ring-shaped placement table 4 is provided. The periphery of the semiconductor wafer W on the bottom side thereof is made contact into the inner circumference of the placement table 4 on the top side thereof, and, thus, the wafer is supported by the placement table 4. This placement table 4 is fixed on a top end of a cylindrical leg part 6 which is supported by a bottom of the processing chamber 2 via a ring-shaped bearing part 3. Thus, the placement table 4 is rotatable along a circumferential direction of the cylindrical leg part 6.

A rack 10 is provided on the inner wall of the leg part 6 along the circumferential direction of the leg part 6. Further, a driving shaft 14 of a driving motor 12 provided beneath the chamber 2 projects upward through the bottom of the chamber 2 in an airtight manner. The driving shaft 14 has a pinion 16 fixed on the top thereof which is engaged with the above-mentioned rack 10. Thereby, the leg part 6 and the placement table 4 integral therewith are rotated. Further, a flat transmitting window 18 made of a quarz glass, for example, is provided on the top of the processing chamber 4 in an airtight manner. Further, above the transmitting window 18, plurality heating lamps 20 are provided. Then, by means of radiant heat from the lamps 20, the wafer is heated to a predetermined temperature. As a result of the placement table 4 being rotated at a time of the heating, the wafer placed on the placement table 4 is heated while it is rotated. Accordingly, the temperature of the wafer is made uniform throughout the surface thereof.

In this system, the heating lamps 20 include, as shown in FIG. 2, for example, approximately spherical lamp bodies 22, and reflective plates 24 provided at the rear side of the lamp bodies 22 and formed to be depressed. Thereby, the radiant heat can be efficiently used. Further, in order to enable supply of large power, the lamp bodies 22 include therein filaments 26 extending toward the wafer spirally. Such a type of lamp bodies are called 'single-end type lamp bodies'. In this case, the plurality of heating lamps 20 are arranged so as to cover the top surface of the above-mentioned semiconductor wafer . Power can be supplied to these lamps 20 individually so that the lamps 20 can be controlled for respective zones to which the top surface of the wafer W is divided.

FIGS . 3 and 4 show another thermal processing system in the related art. In this system, instead of the sphere-liked lamp bodies 22 described above, rod-like lamp bodies 28 are employed in heating lamps 30. At the rear side of the lamp bodies 28, reflective plates 32 each having a sectional shape of approximately hemisphere are disposed. In each lamp body 28, a spirally wound filament 34, for example, is contained so as to extend along a longitudinal direction of the lamp body 28, and electric terminals 36 are provided on both ends of the lamp body 28, Such a type of lamp body 28 is called a 'double-end type lamp body' . The heating lamps 30 are disposed in parallel with predetermined intervals.

When the sphere-shaped lamps 20 with the depressed reflective plates 24 are used as shown in FIGS. 1 and 2 , directivity and controllability of the radiant heat are satisfactory. However, in this structure of each lamp 20, the amount of radiant heat in horizontal directions is large, and it is reflected so as to be directed toward the wafer, and energy is lost each time of the reflection. Accordingly, a large amount of energy is lost.

In contrast thereto, when the rod-shaped lamps 30 shown in FIGS. 3 and 4 are used, a large amount of radiant heat is directly irradiated to the wafer.

Accordingly, the energy loss is relatively small. However, in this case, each lamp body 28 should cover a relatively large area of the surface of the wafer. Further, because the lamp body 28 is disposed across the wafer, the directivity thereof is degraded. Accordingly, it is difficult to control the temperature of the wafer for the respective zones at high accuracy.

Further, in order to improve the directivity of the radiant heat, a distance D between the surface of the wafer W and the heating lamps 20, for example (see FIG. 1) , should be shortened so that diffusion of the radiant heat is made smaller.

For example, FIGS. 5A and 5B are graphs showing relationships between the directivity of heating lamps and the distance D. FIG. 5A shows the directivity for D of 55 mm, while FIG. 5B shows the directivity for D of 35 mm. Each curve in the figures represents a temperature dependency on the wafer for a respective heating lamp. As can be seen from the figures, in the case of FIG. 5A, the peak of each curve is gentle. Accordingly, the number of heating lamps contributing heating of a specific zone of the wafer is large, and, thus, the directivity is low. In contrast thereto, in the case of FIG. 5B, as the peak of each curve is sharp, the number of heating lamps contributing a specific zone of the wafer is small, and thus, the directivity is high.

Thus, in order to improve the directivity of heating lamps, it is. preferable to shorten the distance D. However, in a case where thermal processing of the wafer is performed in a vacuum atmosphere (pressure-reduced atmosphere) , a thickness t of the transmitting window 18 made of quarz glass should be on the order of 30 through 40 mm for a diameter thereof on the order of 400 mm, for example, so as to secure a high pressure resistivity of the transmitting window 18. Thereby, the directivity of the heating lamps are degraded, and, also, the temperature controllability is degraded as a result of the heat capacity of the transmitting window 18 being increased due to the increased thickness t thereof.

In order to solve this problem, the pressure resistivity of the transmitting window 18 may be increased as a result of shaping it to a dome shape having an approximately hemisphere shape, for example, as shown in

FIG. 6. However, in this case, although it is possible to reduce the thickness of the transmitting window 18 itself to the order of 10 through 20 mm, the total height H of the dome-shaped transmitting window 18 is on the order of 60 through 70 mm. Accordingly, this method cannot solve the problem in that the distance D shown in FIG. 1 should be shortened.

In order to uniformly heat the wafer W, heating lamps 22a may be arranged as shown in FIGS. 7A and 7B instead of the arrangement of the heating lamps 20 shown in FIG. 1. This case also uses the above-mentioned single-end type lamps 22a so as to project to the wafer W approximately perpendicularly. In this arrangement, the heating lamps 22a are disposed along three concentric circles having different radii in a plane facing the wafer W, as shown in FIG. 7A. The lamps 22a are formed in a reflective plate 25 and are provided in respective recess parts 27a having predetermined shapes, as shown in FIG. 7B, so that light emitted by the lamps 22a is reflected by the reflective plate 25.

Instead thereof, a case shown in FIGS. 8A and 8B uses above-mentioned double-end rod-type lamps 22b. In this case, as shown in FIG. 8A, the heating lamps 22b are disposed in parallel to each other with predetermined intervals in a plane facing the wafer W. Also in this case, the lamps 22b are formed in a reflective plate 25 and are provided in respective recess parts 27b having predetermined shapes, as shown in FIG. 8B, so that light emitted by the lamps 22b is reflected by the reflective plate 25.

In the case shown in FIGS . 7A and 7B employing the single-end lamps 22a, as each lamp 22a is slender and extends perpendicular to the wafer W, an area irradiated by the lamp is narrow. That is, although light is irradiated from the lamp 22a both laterally and longitudinally, the light directly applied to the wafer W is one emitted from the extending end thereof longitudinally, while, the light emitted laterally from the lamp 22a reaches the wafer W after being reflected in the recess part 27a of the reflective plate 25, as shown in FIG. 9A. The shape of the recess part 27a is determined so that the light reflected therein uniformly irradiates the wafer W. However, as the lamp 22a spotlights the wafer W, the area irradiated thereby is narrow as shown in FIG. 9B. As the periphery of the wafer W has a larger amount of heat discharged therefrom, the temperature thereof decreases. Thus, a temperature distribution appears radially in the wafer W, which should be corrected by means of the heating lamps. Further, the temperature distribution of the wafer W is controlled through the control of luminous intensity distribution of the heating lamps .

In the case of employing the above-mentioned single-end lamps 22a, as the area irradiated is narrow as mentioned above, it is possible to freely control the luminous intensity distribution of the heating lamps for the surface of the wafer W as a result of power supplied to the lamps 22a and/or the shapes of the recess parts 27a of the reflective plate 25 are controlled appropriately. Thus, high controllability for the luminous intensity distribution can be obtained. Thereby, it is easy to control the radial temperature distribution of the wafer W.

However, in the case of using the single-end lamps 22a, as the portion of the lamp 22a facing the wafer W is narrow, and also, as mentioned above, the amount of light directly applied to the wafer W is small and the large amount of light is reflected by the reflective plate 25, energy loss is large and efficiency is low.

In the case of using the double-end lamps 22b, as the rod-type lamps 22b each having a circular cross section are arranged in parallel to each other so that parts of the lamps 22b along the longitudinal directions thereof face the wafer W. As a result, the areas on the wafer W irradiated by the lamps 22b are wide. That is, light is emitted from the lamp 22b radially, and, from the part of the lamp 22b facing the wafer W, the light is directly applied to the wafer W, and the light reaches the wafer W in a condition in which the light is spread. Thus, when employing these lamps 22b as mentioned above, the part of the lamp 22b facing the wafer W is wide, and the amount of light directly applied to the wafer W is large. Accordingly, the energy loss due to the reflection is small, and thus, the efficiency is high. However, because the area on the wafer W for which the light applied directly from the lamp 22a is wide, it is difficult to control the illumination range even by controlling the shape of the recess part 27b of the reflective plate 25. Accordingly, controllability of luminous intensity distribution is low. By controlling the power supplied to the respective lamps 22b individually, it is possible to control the luminous intensity distribution along Y directions shown in FIG. 10. However, it is not possible control the luminous intensity distribution along X directions. As a result, it is difficult to achieve a proper luminous intensity distribution. Further, light emitted from a part of the lamp 22b other than the part facing the wafer W is not used for heating the wafer W, and is lost as energy.

DISCLOSURE OF THE INVENTION

The present invention has been devised in consideration of the above-described problems, and, an object of the present invention is to provide a system and method of thermal processing employing heating lamps having high directivity and high temperature controllability. Another object of the present invention is to provide a system and method by which a to-be-processed object can be heated in a condition in which the temperature of the surface of the to-be-processed object is highly controlled to be uniform, through radial, control of the temperature of the to-be-processed object.

A thermal processing system, according to the present invention, performs predetermined thermal processing on an approximately circular to-be-processed object, by applying radiant heat to the to-be-processed object by means of a heating lamp system, wherein: the heating lamp system comprises a plurality of lamps disposed concentrically so as to correspond to the to-be-processed object. Thereby, it is possible to heat the to-be- processed object for respective concentric zones, individually, for example. Accordingly, it is possible to improve the directivity of the radiant heat of the lamps and controllability of the temperature of the to-be- processed object such as a wafer W.

The plurality of lamps may comprise a combination of double-end lamps and single-end lamps.

In this configuration, by disposing the single- end lamps for heating the periphery of the wafer W, as shown in FIG. 23, it is possible to heat the periphery of the wafer W effectively more than the center thereof. Accordingly, it is possible to make the temperature of the wafer W uniform effectively during heating it.

The thermal processing system may further comprise: a transmitting window between the heating lamp system and the to-be-processed object; and a reinforcing member reinforcing the transmitting window.

By providing the reinforcing member, it is possible to reduce the thickness of the transmitting window effectively even in a case where a processing chamber is provided for sealing up the wafer W in an airtight manner and thermal processing is performed under a reduced pressure atmosphere therein. Accordingly, it is possible to reduce the distance between the heating lamp system and the wafer W. Thereby, it is possible to further improve the directivity of the radiant heat.

Further, as it is possible to reduce the heat capacity of the transmitting window due to reduction in thickness thereof, it is possible to further improve the controllability of the temperature of the wafer W for the respective zones.

Further, by using double-end tube-like lamps disposed concentrically in the heating lamp system, it is possible to efficiently utilize the radiant heat of the lamps for heating the wafer W. Furthermore, by forming, in the reinforcing member, concentric slits corresponding to the concentrically disposed plurality lamps, it is possible to efficiently utilize the radiant heat of the lamps for heating the wafer W. Other objects and further features of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings .

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows one example of a thermal processing system in the related art;

FIG. 2 shows an arrangement of heating lamps of -li¬

the system shown in FIG. 1;

FIG. 3 shows another example of a thermal processing system in the related art;

FIG. 4 shows an arrangement of heating lamps of the system shown in FIG. 3;

FIGS. 5A and 5B show graphs of relationship between the directivity of heating lamps and distance from the lamps ;

FIG. 6 shows a sectional view of a dome-shaped transmitting window in one example;

FIGS. 7A and 7B show single-end lamps used in a thermal processing system in the related art;

FIGS . 8A and 8B show double-end lamps used in a thermal processing system in the related art; FIGS. 9A and 9B show characteristics of the single-end lamp shown in FIGS. 7A and 7B;

FIG. 10 illustrates characteristics of the double-end lamps shown in FIGS. 8A and 8B;

FIG. 11 shows a side-elevational sectional view of a thermal processing system in a first embodiment of the present invention;

FIG. 12 shows a cross-sectional view of the thermal processing system shown in FIG. 11 taken along a line A-A; FIG. 13 shows a plan view of a supporting frame member of the thermal processing system shown in FIG. 11; FIG. 14 shows a plan view of an arrangement of heating lamps of a heating lamp system of the thermal processing system shown in FIG. 11; FIG. 15 shows a plan view of another arrangement of heating lamps of a heating lamp system which also can be instead employed in the thermal processing system shown in FIG. 11; FIG. 16 shows a plan view of another arrangement of heating lamps of a heating lamp system which also can be instead employed in the thermal processing system shown in FIG. 11; FIG. 17 shows a plan view of another supporting frame member which also can be instead employed together with the heating lamp system shown in FIG. 16 in the thermal processing system shown in FIG. 11;

FIG. 18 shows a plan view of another arrangement of heating lamps of a heating lamp system which also can be instead employed in the thermal processing system shown in FIG. 11;

FIG. 19 shows a side-elevational sectional view of a thermal processing system in a variant embodiment of the first embodiment of the present invention shown in FIG. 11 in which thermal processing is performed under atmospheric pressure;

FIG. 20 shows a side-elevational sectional view of a thermal processing system in a second embodiment of the present invention;

FIG. 21 shows a plan view of an arrangement of heating lamps of a heating lamp system of the thermal processing system shown in FIG. 20;

FIG. 22 shows a perspective view of an arc- shaped lamp used in the heating lamp system shown in FIG. 21;

FIG. 23 shows a plan view of an arrangement of heating lamps of a heating lamp system which also can be instead employed in the thermal processing system shown in FIG. 20;

FIGS. 24A and 24B show characteristics of change, due to elapsing of time, of a surface of a wafer when the wafer is heated by heating lamp system of the present invention and in the related art; and

FIG. 25 shows a plan view of an arrangement of heating lamps of a heating lamp system which also can be instead employed in the thermal processing system shown in FIG. 20.

BEST MODE FOR CARRYING OUT THE INVENTION

A thermal processing system in a first embodiment of the present invention will now be described. FIG. 11 shows a configuration of the thermal processing system in the first embodiment, and FIG. 12 shows a cross-sectional view of the same thermal processing system taken along a line A-A shown in FIG. 11. FIG. 13 shows a plan view of a supporting frame member, and FIG. 14 shows a plan view indicating an arrangement of tube-shaped heating lamps. As shown in the figures, this thermal processing system 40 includes a processing chamber 42 formed to be like a cylinder from stainless steel, aluminum, or the like, for example. In a side wall of the processing chamber 42 near^' the top thereof, a processing gas nozzle 44 for supplying a necessary processing gas into the processing chamber 42 is provided, and, a discharge mouth 46 is provided in the side wall of the processing chamber 42 opposite to the above-mentioned nozzle 44. To the mouth 46, a vacuum pump or the like, not shown in the figure, is connected, so that the processing chamber 42 can be made vacuum thereby.

In the processing chamber 42, a support ring 48 is provided acting as a placement table shaped to be a circular ring, for example, so as to support a to-be- processed object, such as a semiconductor wafer W. This support ring 48 is connected to the top end of a leg part 50 formed to be like a cylinder. Then, the above- mentioned support ring 48 has a wafer holding part 51 formed as a result of the inner part of the top end of the ring 48 being cut out to have an L-shaped section circumferentially. The rear side of the periphery of the semiconductor wafer W regarded as the to-be-processed object is made contact with the wafer holding part 51. Thus, the wafer W is supported/held by the support ring 48. As the temperature of the wafer W becomes such a high temperature as maximum 1000 °C, for example, the support ring 48 is made of ceramics superior in heat resistivity, such as SiC, for example. Further, a heat insulating material such as a quarz glass is employed as a connecting part 53 between the support ring 48 and leg part 50 for the purpose of thermally protecting magnets or the like, described later, provided on the leg part 50. Magnet parts 52 and coil parts 54 are provided on the side wall of the leg part 50 and the processing chamber 42 near the bottom thereof. Specifically, as also shown in FIG. 12, the magnet parts 52 include a pair of permanent magnets, for example, disposed apart from one another on the outer circumferential surface of the leg part 50 in directions of a diameter thereof.

The coil parts 54 include a plurality of coil units 56 disposed on an inner circumferential wall of the processing chamber 42 circumferentially with predetermined intervals (electric angles) . These coil units 56 are set in positions such as to face the above-mentioned magnet parts 52 with a slight gap in a horizontal level . An alternate (electric) current is caused to flow through each coil unit 56, having a predetermined phase difference, for example, in sequence circumferentially. Thereby, a rotating magneitic field, the rotation speed of which can be controlled, can be formed near the bottom of the processing chamber 42. Then, the magnet parts 52 magnetically attracted by the rotating magnetic field is attracted so as to follow the rotation of the rotating magnetic field. Accordingly, the led part 50 is rotated thereby.

In this case, the bottom end of the leg part 50 is not connected to the bottom of the processing chamber 42, and can float therefrom. Specifically, as shown in FIG. 11, in a middle level of the leg part 50, a circular- ring-like floating magnet part 58 is mounted and fixed to the outer circumferential wall of the leg part 50 , circumferentially so as to be like a flange. The floating magnet part 58 is a circular-ring-shaped permanent magnet made from a thin plate, for example, and extends horizontally.

It is assumed that the top side of the floating magnet part 58 has an N pole while the bottom side thereof has an S pole. A magnet holding recess part 60 is formed in the inner circumferential wall of the processing chamber 42, extending horizontally and circumferentially, so as to hold therein the above-mentioned flange-like floating magnet part 58, in a freely movable state.

The magnet holding recess part 60 is formed to be like a ring circumferentially along the inner circumferential wall of the processing chamber 42.

Further, a plurality of magnet units 62 are provided in the magnet holding recess part 60 at predetermined positions such as to magnetically apply a floating force to the floating magnet part 58. Specifically, as shown in FIG. 12, the magnet units 62 include three units 62 along the circumferential inner wall of the processing chamber 42 with equal intervals. The respective magnet units 62 include upper coil units 62A, 62B and 62C and lower coil units 62a, 62b and 62c so as to sandwich the above- mentioned floating magnet part 58 vertically.

Electromagnetic forces, for example, repellent forces, generated by the respective coil units 62A, 62B, 62C, 62a, 62b and 62c are controllable by control of electric currents caused to flow therethrough individually. In this case, the electric currents are caused to flow through the respective coil units in directions such as to cause the electromagnetic repellent forces to be generated thereby so as to cause these coil units to repel the above-mentioned floating magnet part 58. As a result, the leg part 50, that is, the floating magnet part 58 floats. Although not shown in the figures , sensors are provided in the leg part 50 for detecting the horizontal and vertical positions of the leg part 50. Thereby, the electric currents flowing through the coil units are appropriately controlled.

The top of the processing chamber 42 is open, and, at this position, the above-mentioned supporting frame member 66 is provided via a sealing member 64 such as an O-ring, for example. Further, above the supporting frame member 66, a transparent transmitting window 68 made of quarz is mounted via a sealing member 70 such as an 0- ring circumferentially in an airtight manner. Specifically, the top surface of the supporting frame member 66 is in contact with the bottom surface of the transmitting window 68, so that the pressure-resistivity of the transmitting window is improved. For example, the entirety of the supporting frame member 66 is made of a material, such as aluminum, stainless steel or the like, which does not cause any problem such as metal contamination. This supporting frame member 66 has a circular-ring-shaped periphery, and, inside thereof, a plurality of supporting frames 72 are formed in parallel to each other with approximately equal intervals , as shown in FIG. 13. In the figure, the number of supporting frames is 5. However, actually, it is 10 odd, for example, corresponding to the diameter of the wafer W.

Further, although the plurality of supporting frames 72 are provided in parallel to each other in this example, the configuration of the supporting frames is not limited thereto. For example, it is also possible that a plurality of supporting frames are provided perpendicularly to each other so as to be like a lattice. By providing the supporting frame member 66 which supports the transmitting window 68 by a plane, it is possible to maintain high pressure resistivity of the transmitting window 68 even when the thickness t of the transmitting window 68 is made smaller. As the number of supporting frames 72 is increased, the pressure resistivity is improved. However, in consideration of the amount of radiant heat generated by a heating lamp system to be transmitted by the transmitting window 68, it is preferable to set the opening ratio (ratio of the area for which the radiant heat can pass through) to be equal to or larger than 60 % .

Further, as shown in FIG. 13, temperature controlling medium paths 74 are formed in the supporting frames 72 and the periphery of the supporting frame member 66 through drilling by means of a drill. One end of each of the paths 74 communicates with an inlet header 78 having a medium inlet 76, in common. Further, the other end thereof communicates with an outlet header 82 having an outlet 80, in common. Thereby, when heating is performed, a hot water is caused to flow therethrough. When cooling is performed, a cold water is caused to flow therethrough. Thus, the supporting frame member 66 and thus transmitting window 68 are heated or cooled so that temperature control therefor is performed.

Above the transmitting window 68, a lamp box 84 is provided. In the lamp box 84, the above-mentioned heating lamp system 86 is provided, and heats the semiconductor wafer W inside the processing chamber 42 by means of the radiant heat therefrom. Specifically, as shown in FIG. 14, the heating lamp system 86 includes a plurality of tube-like heating lamps 90, each having electric terminals 92 at both ends, disposed concentrically so as to correspond to the semiconductor wafer W having an approximately circular shape. In the example shown in FIG. 14, a plural types of pairs of approximately semicircular tube-like heating lamps 90 having different bending radii are disposed concentrically. The electric terminals 92 of the respective heating lamps 90 are connected with electric power supply wires (not shown in the figure) . Inside of each of the tube-like heating lamps 90, a filament 94 (see FIG. 11) is provided so as to be connected between the two terminals 92. Thus, each heating lamp 90 is a halogen lamp, for example.

The above-mentioned concentrically disposed tube-like heating lamps 90 are used for heating a plurality concentric zones, that is, an inner zone 96A, a middle zone 96B and an outer zone 96C, of the surface of the wafer W, as shown in FIG. 14, for example. In the example of FIG. 14, the heating lamps 90 are disposed so that a single circle of lamps 90 are provided for the inner zone 96A, double circles thereof are provided for the middle zone 96B and double circles thereof are provided for the outer zone 96C. However, actually, further larger number of different-diameter circles of la ps are provided therefor.

Then, above each of the respective tube-like heating lamps 90, a reflective plate 98 having an approximately semicircular section or trapezoidal section is mounted. Thereby, also the light reflected thereby is made to be applied to the wafer W. In FIG. 14, indication of the reflective plates 98 is omitted.

The above-mentioned tube-like heating lamps 90 are connected with a lamp control part 100 for each zone. Further, on the bottom of the processing chamber 42, a plurality of radiation thermometers 102 corresponding to the respective zones are provided, as shown in FIG. 11, and, the temperatures of the heating lamps 90 are controlled for the respective zones according to a feedback manner based on the wafer temperatures obtained through the respective radiation thermometers 102. Thus, the temperature of the wafer W is maintained to be a predetermined temperature.

In FIG. 11, a gate valve 104 is opened/closed when the semiconductor wafer W is conveyed into and out from the processing chamber 42. Further, although not shown in the figure, a lifter pin for lifting/lowering the wafer W is also provided at a bottom part of the processing chamber 42 which works during the conveyance of the wafer W.

Operation of the thermal processing system in the first embodiment of the present invention described above will now be described.

First, the semiconductor wafer W is brought in into the processing chamber 42 which is maintained in a vacuum condition, from a load lock room or the like, not shown in the figures, via the opened gate valve 104. This wafer W is placed on the wafer holding part 51 of the support ring 48 by means of the above-mentioned lifter pin, and is held thereby.

Then, after thus bringing in of the wafer W is completed, the gate valve is closed so that the processing chamber 42 is sealed, and, also, a predetermined processing gas corresponding to a process to be performed on the wafer W is provided into the processing chamber 42 via the processing gas nozzle 44 while the pressure in the processing chamber 42 is being reduced. Then, the predetermined process pressure is maintained in the processing chamber 42. For example, in a case where a deposition process is performed on the wafer W as the thermal processing, a deposition gas is provided into a processing space S in the processing chamber 42 together with a carrier gas such as N₂ gas.

Then, the heating lamp system 86 provided at the top of the processing chamber 42 is driven so that the heating lamps 90 are turned on. Then, heat rays emitted by the heating lamp system 86 are incident into the processing space S through the transparent transmitting window 68. Then, the heat rays are applied onto the top surface of the semiconductor wafer W, and, thereby, the surface of the wafer W is heated into a predetermined temperature. Then, it is maintained in this temperature. Simultaneously, the respective coil units 56 of the above-mentioned coil parts 54 provided at the lower part of the inside of the processing chamber 42 have the alternate (electric) currents having predetermined phase differences flowing therethrough in sequence. Thereby, the rotating magnetic field having the predetermined rotation speed is formed inside the processing chamber 42 (see FIG. 12) . Then, the magnet parts 52 of the leg part 50 move so as to follow the rotating magnetic field. Accordingly, the leg part 50 and support ring 48 rotate thereby. As a result, the semiconductor wafer W held by the support ring 48 is rotated during the thermal processing interval. Thereby, a condition in that the temperature of the wafer W is made uniform throughout the surface of the wafer W is maintained.

Further, at this time, the upper and lower coil units 62A, 62B, 62C, 62a, 62b and 62c of the three respective floating magnet parts 62 provided in the magnet holding recess part 60 of the processing chamber 42 have electric currents flowing therethrough so that the repellent forces are generated between these coil units and the flange-shaped floating magnet part 58 located between the coil units. By the repellent forces, the flange-shaped floating magnet part 58 and the leg part 50 integral therewith float. Accordingly, the leg part 50 is rotated in a condition in which it floats magnetically. As a result, the leg part 50 is rotated stably in the magnetically floating condition. Thus, the leg part 50 is supported without using any bearing or the like, in a non- contact condition. As a result, problems such as generation of particles due to friction, metal contamination and so forth can be avoided.

Further, the transmitting window 68 is reinforced as a result of the bottom surface of the transmitting window 68 being firmly supported by the supporting frame member 66 having the plurality of supporting frames 72 in a surface contact condition so that the pressure resistively of the transmitting window 68 is considerably improved. Accordingly, it is possible to reduce the thickness of the transmitting window 68. For example, in the system in the related art shown in FIG. 1, the thickness of the transmitting window should be 30 through 40 mm for the diameter of 400 mm. However, in the embodiment of the present invention described above, merely the thickness on the order of 2 through 5 mm is sufficient. Accordingly, it is possible to reduce the thickness t of the transmitting window 68 remarkably. By reducing the thickness t of the transmitting window 68, it is possible to reduce the distance D between the surface of the wafer W and the heating lamp system 86. Thereby, it is possible to improve the directivity of the radiant heat from the heating lamp system 86.

Furthermore, the medium paths 74 are provided in the supporting frames 72 of the supporting frame member 66 as shown in FIG. 13. By causing the temperature controlling medium such as coolant, that is, cooling water, for example, to flow therethrough, when cooling is performed, for example. Thereby, it is possible to cool the supporting frame member 66 and thus the transmitting window 68 thereabove to a temperature on the order of the room temperature of the processing chamber 42. Accordingly, occurrence of metal contamination due to melting of the supporting frame member 66, adherence of reaction by-product or the like to the bottom surface of the transmitting window 68 or the surface of the supporting frame member 66, and so forth, especially in a case of deposition profess, can be avoided. Further, by controlling the cooling temperature to a fixed temperature by controlling the temperature and/or flow rate of the coolant, thermal influence given to the wafer W by the supporting frame member 66 and transmitting window 68 can be made to be always constant. Accordingly, it is possible to eliminate variations in degree of thermal processing performed on the respective wafers W, one by one, which may be easily affected by the temperature sensitively. Thereby, it is possible to remarkably improve repeatability. In a case where the transmitting window 68 should be heated due to a request according to a process, a heat medium is caused to flow through the paths 74.

In the above-described embodiment, the heating lamp system 86 includes the concentrically disposed tubelike heating lamps 90 formed to have approximately semicircular shapes, and, also, the powers supplied to the lamps 90 are controlled for the respective zones independently through control by the control part 100. Accordingly, first, in comparison to the case of employing the single-end lamps shown in FIGS. 1, 2, 7A and 7B, a large amount of radiant heat emitted from the lamps 90 is not reflected but directly applied to the wafer W.

Accordingly, it is possible to efficiently heat the wafer W. Further, as mentioned above, the periphery of the wafer W may have a relatively large amount of discharged heat in comparison to the center thereof. In order to deal with such a situation, in the above-described embodiment, as a result of the lamps 90 being disposed concentrically as mentioned above and the supply powers being controlled for the respective zones, individually, it is possible to improve the directivity thereof, and, also, to perform temperature control at high accuracy. Thus, it is possible to control the temperature of the surface of the wafer W to be uniform throughout the surface of the wafer W effectively. The above-mentioned directivity can be improved also by reducing the thickness t of the transmitting window 68 as mentioned above.

Accordingly, the directivity can be further improved.

In the example of FIG. 14, each heating lamp 90 is formed to be like a semicircle. However, the opening angle of the arc shape thereof is not limited thereto, and, it is possible to form each heating lamp 90 into an arc shape having the opening angle of 90 ° (1/4 arc) , an arc shape having the opening angle of 60 ° (1/6 arc) , or the like. Further, it is also possible that tube-like heating lamps having arc shapes having different opening angles for different zones are combined.

Further, it is also possible to employ approximately circular ring-shaped tube-like heating lamps 90A in each of which only a part of a circle is cut out, as shown in FIG. 15.

Further, as shown in FIGS. 16 and 17, in the supporting frame member 66, supporting frames 72A including temperature controlling medium paths 74A may be shaped so as to prevent these supporting frames 72A from blocking the radiant heat emitted from concentrically disposed arc-shaped tube-like heating lamps 90C shown in FIG. 16. In this example, as shown in FIG. 17, slits 72B are formed in locations such as to correspond to the locations of the respective arc-shaped tube-like heating lamps 90C shown in FIG. 16. Accordingly, the radiant heat emitted by the lamps 90C can effectively reach the wafer W through the transmitting window 68 and thus be efficiently utilized for heating the wafer W. Further, as shown in FIG. 18, it is also possible to employ a plurality of straight-rod-shaped tube-like heating lamps 90B, which may be general-purpose ones and thus inexpensive, disposed approximately concentrically for the respective zones. In this case, the length of each straight-rod-shaped heating lamp 90B should be different so as to correspond to the curvature of the respective zone.

Further, it is also possible to appropriately combine these straight tube-like heating lamps 9OB with the above-mentioned arc-shaped tube-like heating lamps 90 , 90A.

Further, in the above-described embodiment, processing is performed under a reduced pressure atmosphere or a vacuum atmosphere such as in a CVD process. However, in a case where thermal processing is performed under an atmospheric pressure atmosphere or an atmosphere near the atmospheric pressure atmosphere, such as in an annealing process, diffusion process and so forth, it is not necessary to provide the supporting frame member 66 to increase the pressure resistivity of the transmitting window, shown in FIG. 11. In this case, as shown in FIG. 19, the transmitting window 68 is set directly at the top of the processing chamber 42 only via the O-ring 64.

Thereby, it is possible to further reduce the distance D between the surface of the wafer W and the heating lamp system 86. Accordingly, the directivity of the heating lamp system 86 is further improved, and thus, it is possible to further improve the accuracy of temperature control for the respective zones .

Further, in the above-described embodiment, the supporting frame member 66, transmitting window 68 and heating lamp system 86 are set at the top part of the processing chamber 42. However, it is also possible to set them at a bottom part of the processing chamber 42 , or to set them at the top part and bottom part, respectively. Further, although the to-be-processed object is a semiconductor wafer W in the embodiment, it is also possible to apply the present invention for a glass substrate, a LCD substrate, or the like.

FIG. 20 show a side-elevational sectional view of a thermal processing system in a second embodiment of the present invention. This system includes a flat processing chamber 102 made of aluminum (A5052) , for example, and has an inner side wall having a circular cross-sectional shape. The processing chamber 102 has a ring-shaped groove part 121 in the periphery at a bottom part thereof. An inner ring part 131 is provided in the groove part 121. The inner ring part 131 is provided on an inner wall of the groove part 121 via a bearing part 141 and is supported thereby rotatably around a vertical axis. At a top end of the inner ring part 131, a ring- shaped placement part 122 , made of a silicon carbonate (SiC) , for example, for holding the periphery of a wafer W acting as a to-be-processed object, is provided, and is rotated together with the inner ring part 131 integrally. A housing 123 forming the groove 121 extends downward as a part of the processing chamber 102, and, an outer ring part 132 is held by the housing 123 rotatably around a vertical axis via bearing parts 142 and 143 provided as two stages arranged vertically on the outer wall of the housing 123. The above-mentioned bearing parts 141, 142 and 143 have the same structures each being a ceramic bearing for vacuum use. For example, with regard to the bearing part 143, as a typical one thereof, balls 143a made of silicon nitride superior in abrasion resistively, heat resistively and corrosion resistively are held by a holder 143b made of a self-lubricative material such as fluororesin.

Magnetic poles 133 and 134 are provided on the above-mentioned inner ring part 131 and outer ring part 132, respectively, and thus form a magnetic coupling as a result of being disposed on the inner and outer surfaces of a partition 124, respectively. The partition 124 is formed of a non-magnetic material such as aluminum or non- magnetic steel (SUS304, for example) . The inner ring part 131 is made of a martensitic stainless steel (SUS440C) which is a high-permeability material, and, has a plurality of, for example, 60 rectangular projections (not shown in the figure) along the outer circumferential periphery thereof. These projections correspond to the above-mentioned magnetic poles 133.

The outer ring part 132 has, for example, 60 permanent magnets (not shown in the figure) made of neodymium magnets corresponding to the magnetic poles 134 and corresponding to the above-mentioned magnetic poles 133 of the inner ring part 131. A gear part 135 is formed on an outer peripheral surface of the outer ring part 132. The gear part 135 is engaged with a gear part 137 of a stepper motor 136 which is a driving part. Thereby, the stepper motor 136 drives so as to rotate the outer ring part 132.

A supply path 144 for purge gas such as N₂ gas, for example, is formed at a portion near the outside of the above-mentioned housing 123. The inner end of the supply path 144 is located immediately above the bearing part 141 in the groove part 121. Further, a plurality of discharge paths 145 for the purge gas, for example, are formed and arranged circumferentially, at a portion of the housing 123 near the inside. The purge gas goes into the groove part 121 via the supply path 144 from a gas supply pipe, not shown in the figure, and, then, is discharged via the discharge paths 145 after passing through the bearing part 141, to a discharge pipe, not shown in the figure, externally.

A lift pin, not shown in the figure, is provided at a bottom part of the processing chamber 102 beneath the wafer W for lifting up the wafer W so as to transfer the wafer to a conveying arm outside of the processing chamber 102. A horizontally elongated slit-shaped gas supply path 127, for example, for supplying processing gas and a discharge path 124 for discharging the processing gas are formed at positions such as to oppose one another in a side wall of the processing chamber 102 slightly above the wafer W. The discharge path 124 is connected to a discharge pipe 126 via a discharge chamber 125 projecting externally from the side wall of the processing chamber 102.

A transmitting window 150 (transparent or translucent) made of quarz, for example, is provided at a top of the processing chamber 102, and, above the transmitting window 150, a heating unit 105 is provided. The heating unit 105 is configured to be larger than the wafer W, for example, and, includes double-end lamps 106 each having end portions 161 at both ends thereof and a reflective plate 151, for example. In FIG. 20, a housing 152 holds a power supply system for the lamps 106. As the above-mentioned lamps 106, halogen lamps are used, for example. These lamps 106 are shaped and disposed so as to form a plurality of approximately concentric light emitting portions around a center of the wafer W with different radii. Specifically, as shown in FIGS. 21 and 22, in the arrangement of the lamps 106, a plurality of circles having different radii are formed by arc-shaped lamps 106. Each circle of the lamps 106 form a ring-shaped lamp having a predetermined diameter. The above-mentioned plurality circles of lamps 106 are disposed concentrically with predetermined intervals. Each circle of lamps 106 forms a respective ring-shaped light-emitting portion. Strictly speaking, slight gaps exists between adjacent lamps 106 of each of the above-mentioned light emitting portions. The above-mentioned end portions 161 of each lamp 106 extend vertically upward at both ends thereof, and the extending ends of the end portions 161 are connected to the power supply system contained in the housing 152. For example, each arc-shaped lamp 106 is configured so that arc-shaped lamps 106 adjacent to one another along radial directions have the end portions 161 which do not adjacent to one another along the radial directions.

These lamps 106 are provided in recess parts 153 formed in the reflective plate 151, respectively. That is, the recess parts 153 each having an approximately semicircular cross-section are formed in the surface of the reflective plate 151 so as to extend along a plurality of concentric circles in locations corresponding to the locations of the lamps 106, respectively. Thus, the heating unit 105 is configured. The reflective plate 151 is formed of a material reflecting light emitted by the lamps 106, such as an aluminum deposited film or the like. The shape of each recess part 153 is such that the light emitted from the lamp 106 is reflected by the inner wall of the recess part 153, and then, reaches the wafer W on the placement table 122. Thus, the light directly coming from the lamps 106 and the light reflected by the inner walls of the recess parts 153 are applied to the wafer W on the placement table 122.

In the example shown in FIG. 21, in a case where an 8-inch-size wafer W is processed thermally, the lamps 106 has an outer diameter of 10 mm, and total 10 ring- shaped light emitting portions are formed thereby. Specifically, the radius of the smallest (most inside) circle is 25 mm, for example, from the center 0 of the reflective plate 151, the radius of the largest (most outside) circle is 187 mm, for example, and each of the intervals therebetween is 18 mm. The most inside circle 170 includes a single arc-shaped lamp 106, the second circle 171 includes two arc-shaped lamps 106, the third circle 172 includes two arc-shaped lamps 106, the fourth circle 173 includes four arc-shaped lamps 106, the fifth circle 174 includes four arc-shaped lamps 106, the sixth circle 175 includes four arc-shaped lamps 106, the seventh circle 176 includes four arc-shaped lamps 106, the eighth circle 177 includes six arc-shaped lamps 106, the ninth circle 178 includes six arc-shaped lamps 106, and the tenth circle 179 includes six arc-shaped lamps 106, for example, as shown in FIG. 21. Operation of the above-described second embodiment shown in FIGS. 20, 21 and 22 will now be described. First, the wafer W is conveyed by the above- mentioned conveying arm, not shown in the figure, to the placement part 122 via a conveying hole of the processing chamber 102, not shown in the figure. Then, the stepper motor 136 is started rotation, and, thereby, the outer ring part 132 is rotated. At this time, magnetic forces are applied between the magnetic poles 134 of the outer ring part 132 and the magnetic poles 133 of the inner ring part 131. Thereby, the magnetic poles 133 are attracted by the magnetic poles 134. As a result, the inner ring part 131 also rotates as a result of the magnetic poles 133 being attracted by the magnetic poles 134. Thus , the wafer W rotates together. Then, while the wafer W is rotated at 90 rpm, for example, predetermined thermal processing is performed on the wafer W as a result of the wafer being heated by radiant heat of the lamps 106 and the processing gas, that is, inert gas such as N₂ gas, for example, being supplied via the supply path 127. This thermal processing may be, for example, anneal processing in which the wafer W is heated to 1000 °C, and, also, the inert gas is supplied. Then, after the thermal processing is finished after a predetermined interval has elapsed, the lamps 106 are turned off as a result of the power supply thereto is stooped, the temperature of the wafer W is decreased thereby, and the stepper motor 136 is stopped after the temperature of the wafer W thus reaches a predetermined temperature. The thus-processed wafer W is conveyed by the conveying arm externally from the processing chamber 102.

As described above, in the second embodiment of the present invention, the ring-shaped lamps are formed from disposing of the arc-shaped lamps 106 circumferentially along the plurality of concentric circles. Accordingly, while high luminous intensity efficiency is maintained, temperature control along radial directions of the wafer W can be performed. In other words, because the double-end arc-shaped tube-like lamps 106 are employed, portions of the lamps facing the wafer W are wide, and the large amount of light emitted from these portions is directly applied to the wafer W. Accordingly, energy loss due to reflection is small, and thus, luminous intensity efficiency is high.

Further, as the many concentric ring-shaped lamps are formed from the many arc-shaped lamps 106, it is possible to control luminous intensities (heating temperatures) of the respective lamps 106 by controlling the powers supplied to the respective arc-shaped lamps 106. Thereby, it is easy to provide an appropriate radial luminous intensity distribution of the wafer W. Accordingly, it is possible to appropriately control the temperature of the wafer W along the radial directions thereof. As mentioned above, a temperature distribution may easily occur along the radial directions of the wafer W. According to the second embodiment of the present invention, by controlling the temperature of the wafer W along the radial directions as mentioned above, it is possible to control the temperature distribution of the surface of the wafer W along the radial directions during heating the wafer W, and, to make the temperature of the surface of the wafer W uniform at high accuracy while increasing the temperature of the wafer W, for example.

Further, by rotating the wafer W with respect to the lamps 106 during heating of the wafer W, it is possible to make the temperature of the surface of the wafer W uniform at higher accuracy during heating or thermal processing thereof. Furthermore, it is necessary to merely control the supply power to the lamps 106 with respect to the radial directions. Accordingly, the control can be easily performed. Further, by disposing the lamps 106 to be like rings facing the wafer W, it is possible to reduce radiation of light from portions which do not contribute heating of the wafer W. Accordingly, it is possible to reduce energy loss. A third embodiment of the present invention will now be described with reference to FIG. 23. In this embodiment, the heating lamp system includes the above- mentioned double-end arc-shaped lamps 106 and, in addition, single-end lamps 108 each having only one end portion connected to an electric power supply wire. Each of the single-end lamps 108 has an approximately spherical shape, as shown in FIG. 7B. These single-end lamps 108 are provided in an area corresponding to a peripheral area of the wafer W such as an area having a width on the order of 80 mm from the outer edge thereof. In this area, the single-end lamps 108 are disposed so as to form predetermined concentric circles , and the extending ends (opposite to the power supply ends) thereof are directed to the wafer W, as shown in FIG. 23. The large number of single-end lamps 108 are used, as shown in the figure. Further, similar to the above-described second embodiment, the arc-shaped lamps 106 are disposed circumferentially so as to form ring-shaped lamps and form a plurality of concentric circles . The other configuration is the same as that of the second embodiment.

By using the above-described third embodiment of the present invention, it is possible to reduce a temperature distribution of the surface of the wafer W during heating thereof. Accordingly, it is possible to avoid occurrence of slip or the like. That is, the placement part 122 of the wafer W is formed of SiC, and, has a higher density and a larger specific heat than those of the wafer W made of Si. Accordingly, increase in temperature is slow in the placement part 122 than in the wafer W. Thereby, heat in the periphery of the wafer W escapes to the placement part 122, and, as a result, the temperature of the periphery of the wafer W becomes lower than that of the center thereof. Thus, a temperature distribution in the surface of the wafer W occurs . This may cause slip.

In the third embodiment, the single-end lamps 108 are used and thereby, the periphery of the wafer W is heated. Because the single-end lamps 108 have slender approximately spherical shapes, and extend vertically, it is possible to dispose them at a high density. Further, as power is supplied to each single-end lamp 108, it is possible to increase a luminous energy for a unit area. Thereby, it is possible to make the luminous energy applied to the periphery of the wafer W larger than to the center thereof during heating the wafer W. Accordingly, it is possible to heat the periphery of the wafer W more than the center thereof. Thereby, it is possible to avoid occurrence of the temperature distribution in the surface of the wafer W. Accordingly, it is possible to avoid occurrence of slip and so forth, and to improve the throughput.

Even in a case where the material of the placement part 122 is such that the increase in temperature of the placement part 122 is the same as that of the wafer W, as the temperature of the wall of the processing chamber 142 is lower, and, as a result, a larger amount of heat is discharged from the periphery of the wafer W, such a temperature distribution in the surface of the wafer W as that mentioned above may occur. Accordingly, heating the periphery of the wafer W by using the single-end lamps 108 as mentioned above is effective/advantageous also in such a case.

FIG. 24A shows characteristics indicating change, due to time elapsing, of the temperature of the surface of the wafer W, when an annealing process is performed on the wafer W by using the heating lamp system in which the single-end lamps 108 and double-end arc-shaped lamps 106 are combined in the above-mentioned third embodiment. On the other hand, FIG. 24B shows characteristics indicating change, due to time elapsing, of the temperature of the surface of the wafer W, when an annealing process is performed on the wafer W by using a heating lamp system in which only double-end straight-rod-shaped lamps are disposed in parallel in the related art as shown in FIGS. 8A and 8B. In any case, the rate of temperature increase is 100 °C/sec, and the temperatures on the surface of the wafer W at positions apart from the center of the wafer W by 0 mm, 35 mm, 78 mm, and 105 mm are measured. As can be seen from the figures , when the heating lamp system of the third embodiment of the present invention is employed, the temperature of the surface of the wafer W is approximately uniform during the temperature increase process. Thus, it has been proved that the wafer W can be heated while the temperature of the surface of the wafer W is uniform from the center through the periphery along the radial directions . As a result, it is possible to control the radial temperature distribution of the wafer W, and to avoid occurrence of slip and so forth.

In embodiments of the present invention, a plurality of ring-shaped light emitting portions having a common center and different sizes should be formed. In such a case, it is possible to form each ring-shaped light emitting portion from a single ring-shaped lamp, or from a plurality of arc-shaped lamps disposed circumferentially, or, as shown in FIG. 25, from a polygonal shape of a plurality of straight-rod-shaped double-end lamps 109 disposed circumferentially, for example. Thus, it is possible to dispose the plurality of polygonal lamps each including the plurality of straight-rod-shaped lamps having the common center and different sizes with predetermined intervals. Also in such a case, while high luminous intensity efficiency is maintained, temperature control along radial directions of the wafer W can be performed.

Further, any thermal processing system according to the present invention can also be applied for a deposition process such as a CVD process, an oxidation process, and so forth, other than the above-mentioned annealing process.

It is also possible to rotate the heating lamp system with respect to the placement part of the wafer W in each embodiment of the present invention. Thereby, it is possible to heat the wafer W further uniformly.

Further, the present invention is not limited to the above-described embodiments, and variations and modifications may be made without departing from the scope of the present invention.

The present application is based on Japanese priority applications Nos . 2000-119325 and 2000-119998, both filed on April 20, 2000, the entire contents of which are hereby incorporated by reference.

Claims

1. A thermal processing system performing predetermined thermal processing on an approximately circular to-be-processed object, by applying radiant heat to the to-be-processed object by means of a heating lamp system, wherein: said heating lamp system comprises a plurality of lamps disposed concentrically so as to correspond to the to-be-processed object.

2. The thermal processing system as claimed in claim 1 , wherein said plurality of lamps comprise double- end lamps .

3. The thermal processing system as claimed in claim 1, wherein said plurality of lamps comprise a combination of double-end lamps and single-end lamps.

4. The thermal processing system as claimed in claim 1 , wherein said plurality of lamps comprise arc- shaped lamps .

5. The thermal processing system as claimed in claim 1 , wherein said plurality of lamps comprise rod- shaped lamps .

6. The thermal processing system as claimed in claim 1, wherein said plurality of lamps are disposed so as to form a plurality of concentric circles having different radii .

7. The thermal processing system as claimed in claim 1, further comprising: a transmitting window between said heating lamp system and the to-be-processed object; and a reinforcing member reinforcing said transmitting window.

8. The thermal processing system as claimed in claim 7 , wherein said reinforcing member comprises a plurality of members disposed in parallel.

9. The thermal processing system as claimed in claim 7 , wherein said reinforcing member is configured so that concentric slits are formed therein corresponding to the concentrically disposed plurality lamps .

10. The thermal processing system as claimed in claim 7, further comprising a sealed processing chamber in which the to-be-processed object is sealed and processed under a reduced pressure atmosphere, wherein: said transmitting window is provided as a part of said processing chamber in an airtight manner; said heating lamp system is provided outside of said processing chamber and applies the radiant heat to the to-be-processed object inside of the processing chamber through said transmitting window.

11. A thermal processing method comprising the step of performing predetermined thermal processing on an approximately circular to-be-processed object, by applying radiant heat to the to-be-processed object by means of a heating lamp system, wherein: said heating lamp system comprises a plurality of lamps disposed concentrically so as to correspond to the to-be-processed object.