Abstract:
A method of detecting a temperature of an object in a multiple-reflection environment by a radiation pyrometer includes the steps of detecting a radiation strength emitted from a target region of an object, applying a correction to the radiation strength so as to correct the effect of multiple reflections of a radiation emitted from the object, applying a correction to the radiation strength so as to correct a reflection loss caused at an end surface of an optical medium interposed between the object and a sensing head of the pyrometer, applying a correction to the radiation strength with regard to an optical absorption loss caused in the optical medium, and applying a correction to the radiation strength with regard to a stray radiation coming in to the sensing head from a source other than the target region of the object.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention generally relates to fabrication of semiconductor devices and more particularly to a rapid thermal processing apparatus.  
           [0002]    The art of rapid thermal processing (RTP) includes the processes such as rapid thermal annealing (RTA), rapid thermal cleaning (RTC), rapid thermal chemical vapor deposition (RTCVD), rapid thermal oxidation (RTO), rapid thermal nitridation (RTN), and the like, and is used extensively in the fabrication process of semiconductor devices including memory integrated circuits and logic integrated circuits.  
           [0003]    A typical fabrication process of a semiconductor integrated circuit includes various thermal process steps such as film deposition, annealing, oxidation, diffusion, sputtering, etching, nitridation, and the like. Thus, a semiconductor substrate is subjected to a number of such thermal process steps.  
           [0004]    An RTP process is a promising substrate processing for improving the yield and quality of semiconductor devices, in view of the fact that the temperature rise and fall are carried out in a short time period at a very large rate. By using an RTP process, the duration in which the substrate is subjected to a high temperature is reduced substantially.  
           [0005]    A conventional RTP apparatus generally includes a cluster-type processing chamber for a single-wafer processing of a substrate, wherein the substrate may be a semiconductor wafer, a glass substrate carrying a photomask, a glass substrate for a liquid crystal display device, a substrate for an optical disk, and the like. The processing chamber has a quartz window and a high-power lamp such as a halogen lamp is disposed adjacent to the quartz window on and/or below the processing chamber so as to heat the substrate in the processing chamber through the quartz window. The lamp carries a reflector at the side opposite to the side in which the substrate is located.  
           [0006]    Typically, the quartz window is formed to have a plate-like form, while a tubular-form window is also possible. In the latter case, the substrate to be processed is accommodated in the tubular quartz window. In the event the processing chamber is evacuated by a vacuum pump, it is preferable to form the quartz window to have a thickness of several ten millimeters (30-40 mm) so as to secure a sufficient mechanical strength for bearing the atmospheric pressure applied to the evacuated processing chamber. In view of the tendency that a thermal stress causes the quartz window to be concaved toward the interior of the processing chamber, there are cases in which the quartz window is provided with a compensating convex curve such that the quartz window projects outward from the processing chamber.  
           [0007]    In order to achieve a uniform heating, a number of halogen lamps are arranged adjacent to the quartz window, wherein the thermal radiation produced by the halogen lamps are directed toward the substrate in the processing chamber by the reflector provided behind the halogen lamps. Typically, the processing chamber has a gate valve on the sidewall thereof for in-and-out operation of the substrate, and a gas supply nozzle is provided also on the sidewall of the processing chamber.  
           [0008]    In such an RTP apparatus, it is important to measure the substrate temperature accurately for achieving reliable processing. For this purpose, there is provided a temperature detector on the processing chamber such that the temperature detector detects the temperature of the substrate in the processing chamber. While such a temperature detector can be formed by a thermocouple, the use of a thermocouple is not preferable in an RTP apparatus as there is a possibility that the metal constituting the thermocouple may cause a contamination of the substrate.  
           [0009]    In view of the situation noted above, conventional RTP apparatuses have used a radiation pyrometer for temperature detection of the substrate, wherein such a radiation thermometer or pyrometer detects the strength of the thermal radiation emitted from the rear surface of the substrate. The thermal radiation strength thus detected is converted to temperature based on the emissivity ε according to the relationship  
             E   m ( T )= ε   E   BB ( T )  (1)  
           [0010]    wherein E m  (T) represents the detected radiation strength while E BB  (T) represents the radiation strength of a black body at the temperature T. The use of such a pyrometer is already disclosed in Japanese Laid-Open Patent Publication 11-258051.  
           [0011]    In operation of the RTP apparatus, a wafer to be processed is introduced into the processing chamber and is held on a wafer stage by a chuck mechanism. Further, a processing gas such as a nitrogen gas or oxygen gas is introduced into the processing chamber from the gas supply nozzle, and the halogen lamp is energized for rapid heating of the wafer. Thereby, the temperature of the substrate is detected by the radiation pyrometer and a controller controlling the energization of the halogen lamp achieves a feedback control in response to the output of the radiation pyrometer.  
           [0012]    On the other hand, such a conventional RTP apparatus using a radiation pyrometer has a drawback in that, because of the small distance between the substrate and the sensing head of the pyrometer, there occurs a temperature rise in the sensing head of the pyrometer as a result of thermal radiation from the wafer and an error is introduced into the result of the temperature detection.  
           [0013]    While such an error can be avoided by providing a cooling fixture to the pyrometer, such a construction increases the size and cost of the RTP apparatus.  
           [0014]    Further, the conventional RTP apparatus using a radiation pyrometer for the temperature detection of the substrate has suffered from the problem of low accuracy of temperature measurement, wherein it was discovered that the problem has been caused not only by the foregoing temperature rise of the pyrometer but also by other reasons.  
           [0015]    As a result of investigation constituting the foundation of the present invention, the inventor of the present invention has discovered that there occurs a deviation in the Eq. (1) noted before, provided that: (1) the sensing head of the pyrometer detects multiple reflection of the thermal radiation emitted by the substrate; (2) there is a thermal radiation coming in from a heat source other than the target region of the wafer; (3) there is a reflection loss at the end surface of the optical medium interposed between the wafer and the sensing head; and (4) there is a substantial absorption loss in the optical medium. In the case of the RTP apparatus, in which a reflective coating is provided on various parts of the processing chamber for improving the thermal efficiency, the effect of the foregoing factors (1) and (2) cannot be ignored.  
         SUMMARY OF THE INVENTION  
         [0016]    Accordingly, it is a general object of the present invention to provide a novel a useful thermal processing apparatus wherein the foregoing problems are eliminated.  
           [0017]    Another and more specific object of the present invention is to provide a thermal processing apparatus wherein accuracy of temperature detection is improved.  
           [0018]    Another object of the present invention is to provide an improved temperature detection method for a thermal processing apparatus wherein the factors causing a detection error are taken into consideration and the detection error is eliminated.  
           [0019]    Another object of the present invention is to provide a method of detecting a temperature of an object disposed in a multiple-reflection environment by way of a radiation pyrometer, comprising the steps of:  
           [0020]    detecting a radiation strength emitted from a target region of said object;  
           [0021]    applying a correction to said radiation strength so as to compensate for the effect of multiple reflections of a radiation emitted from said object;  
           [0022]    applying a correction to said radiation strength so as to compensate for a reflection loss caused at an end surface of an optical medium interposed between said object and said sensing head;  
           [0023]    applying a correction to said radiation strength so as to compensate for an optical absorption loss caused in said optical medium; and  
           [0024]    applying a correction to said radiation strength so as to compensate for a stray radiation coming in to said sensing head from a source other than said target region of said object.  
           [0025]    According to the present invention, the deviation of the temperature detected by the pyrometer from the true temperature is effectively compensated for with regard to: the multiple reflections taking place in the multiple reflection environment; the reflection loss at the surface of the optical medium between the substrate and the sensing head; the absorption loss in the optical medium; and the stray thermal radiation coming in to the sensing head from a source other than the target region of the object. The object may be a substrate or a wafer and the multiple-reflection environment may be a processing chamber of a thermal processing apparatus. Thus, an accurate temperature measurement becomes possible in a thermal processing apparatus by using a pyrometer, and the temperature control in such a thermal processing apparatus is improved.  
           [0026]    Another object of the present invention is to provide a thermal processing apparatus, comprising:  
           [0027]    a processing chamber including therein a stage adapted for supporting a substrate thereon, said processing chamber having an evacuation port for connection to an evacuation system;  
           [0028]    a heat source provided so as to heat said substrate in said processing chamber;  
           [0029]    a radiation pyrometer coupled to said processing chamber for measurement of a temperature of said substrate;  
           [0030]    a control unit for controlling energization of said heat source in response to a temperature of said substrate; and  
           [0031]    a cooling mechanism for cooling a part of said processing chamber in the vicinity of said radiation pyrometer,  
           [0032]    said radiation pyrometer comprising:  
           [0033]    a rotary chopper having a slit and a high-reflective surface and a low-reflective region, said rotary chopper being disposed in an optical path of a radiation emitted from said substrate;  
           [0034]    a transparent rod disposed in said optical path between said substrate and said chopper, said transparent rod allowing a multiple reflection of said radiation between said wafer and said chopper; and  
           [0035]    a detector disposed behind said chipper for detecting said radiation passed through said slit.  
           [0036]    According to the present invention, the distance between the detector and the substrate is increased, and the effect of temperature rise of the detector and associated deviation of the temperature detection are successfully avoided.  
           [0037]    Other objects and further features of the present invention will become apparent from the following detailed description when read in conjunction with the attached drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0038]    [0038]FIG. 1 is a diagram showing the construction of an RTP apparatus according to an embodiment of the present invention;  
         [0039]    [0039]FIG. 2 is a diagram showing the construction of a quartz window used in the RTP apparatus of FIG. 1 in a plan view;  
         [0040]    [0040]FIG. 3 is a diagram showing a part of the quartz window together with a lamp and a reflector in an enlarged view;  
         [0041]    [0041]FIG. 4 is a diagram showing the construction of a lamp applicable to the RTP apparatus of FIG. 1;  
         [0042]    [0042]FIG. 5 is a diagram explaining the effect of the radiation incident to the quartz window obliquely;  
         [0043]    [0043]FIG. 6 is a diagram showing a modification of the reflector of FIG. 3 in an enlarged scale;  
         [0044]    [0044]FIG. 7 is a diagram explaining the effect of the construction of FIG. 6;  
         [0045]    [0045]FIG. 8 is a diagram showing the cooling air flow in the quartz window coupled with the reflector of FIG. 6 in a plan view;  
         [0046]    [0046]FIG. 9 is a diagram showing the relationship between the cooling air passage in the quartz window and the sealing part of the lamp;  
         [0047]    [0047]FIG. 10 is a diagram showing a part of the quartz window for the case the double-ended tubular lamp is replaced with a single-ended bulb;  
         [0048]    [0048]FIG. 11 is a diagram showing the quartz window together with single-ended light bulbs in a plan view;  
         [0049]    [0049]FIG. 12 is a diagram showing the construction of a radiation pyrometer used in the RTP apparatus of FIG. 1 in an enlarged cross-sectional view;  
         [0050]    [0050]FIG. 13 is a diagram showing the construction of a chopper used in the radiation pyrometer of FIG. 12 in a plan view;  
         [0051]    [0051]FIG. 14 is a graph showing the relationship between actual wafer temperature and the wafer temperature obtained by the radiation pyrometer while using a conventional conversion equation with regard to a central part of the wafer;  
         [0052]    [0052]FIG. 15 is a graph showing the relationship between the actual wafer temperature and the wafer temperature obtained by the radiation pyrometer while using a conventional conversion equation with regard to a peripheral edge part of the wafer;  
         [0053]    [0053]FIG. 16 is a diagram explaining the cause of the error that occurs when the conventional conversion equation is used with the radiation pyrometer of FIG. 12;  
         [0054]    [0054]FIG. 17 is a graph showing the relationship between the actual wafer temperature and the wafer temperature obtained by the radiation pyrometer while using a conversion equation according to the present invention with regard to the central part of the wafer;  
         [0055]    [0055]FIG. 18 is a graph showing the relationship between the actual wafer temperature and the wafer temperature obtained by the radiation pyrometer while using a conversion equation according to the present invention with regard to the peripheral edge part of the wafer;  
         [0056]    [0056]FIG. 19 is a diagram showing the result of a simulation with regard to the cooling rate of the wafer in the RTP apparatus of FIG. 1;  
         [0057]    [0057]FIG. 20 is a diagram showing a modification of the RTP apparatus of FIG. 1;  
         [0058]    [0058]FIG. 21 is a diagram showing the state of the RTP apparatus of FIG. 20 when carrying out a rapid heating of the wafer to be processed;  
         [0059]    [0059]FIG. 22 is a diagram showing the state of the RTP apparatus of FIG. 20 when carrying out a rapid cooling of the water to be processed;  
         [0060]    [0060]FIG. 23 is a diagram showing the supply of a thermal conducting gas to the bottom surface of the substrate in the thermal processing apparatus of FIG. 20; and  
         [0061]    [0061]FIG. 24 is a diagram showing a modification of the emission pyrometer of FIG. 12. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0062]    Hereinafter, the construction of a rapid thermal processing (RTP) apparatus  100  will be described with reference to FIG. 1 showing a general construction of the apparatus  100  in a cross-sectional view.  
         [0063]    Referring to FIG. 1, the RTP apparatus  100  generally includes a processing chamber  110 , a quartz window  120 , a heating lamp  130 , a reflector  140 , a support ring  150 , a bearing  160 , a permanent magnet  170 , a gas inlet port  80 , a gas exhaust port  190 , a radiation pyrometer  200  and a system controller  300 .  
         [0064]    The processing chamber  110  is formed of cylindrical chamber body of stainless steel or aluminum, and the quartz window  120  is provided on the processing chamber  110  so as to cover the top opening of the chamber body. By providing the quartz window  120 , a space for processing a wafer W is defined inside the processing chamber  110  such that the space is isolated from the atmospheric environment.  
         [0065]    In order to support the wafer W, there is provided a rotatable cylindrical support member  152  in the processing chamber  110 , wherein the support member  152  carries thereon the support ring  150  on a top part thereof. As noted previously, the wafer W is supported on the support ring  150 .  
         [0066]    The processing chamber  110  has a cylindrical sidewall part  112 , wherein the cylindrical sidewall part  112  carries thereon a gas inlet  180  connected to a gas source not illustrated and an exhaust port  190  connected to a vacuum pump not illustrated. By evacuating through the exhaust port  190 , the interior of the processing chamber  110  is maintained at a reduced pressure environment during the wafer processing process. While not illustrated, the RTP apparatus  100  further includes a gate valve for the in-and-out operation of the wafer W.  
         [0067]    At a bottom part  114  of the processing chamber  110 , there is provided a temperature regulation fixture formed of coolant passages  116   a  and  116   b,  wherein the coolant passages  116   a  and  116   b  are supplied with a cooling medium. Thus, the bottom part  114  of the processing chamber  110  functions as a cooling plate of the substrate W. The cooling plate  114  can be used as a temperature regulator of the substrate. In this case, the temperature regulator includes a temperature sensor and a heater controlled by the system controller  300  and supplies a cooling water as the cooling medium. Alternatively, other cooling media such as alcohol, galden, flon, and the like, may be used. Any known temperature sensor such as PTC thermister, infrared sensor, thermocouple, and the like, can be used for constructing the temperature regulator. The heater may be formed by winding a heating wire around the tubes constituting the coolant passages  116   a  and  116   b.  By controlling the driving current through the heating wire, it is possible to control the temperature of the cooling medium in the coolant passages  116   a  and  116   b.    
         [0068]    The quartz window  120  is provided on the processing chamber  110  via an airtight seal not illustrated so as to sustain the atmospheric pressure, and the thermal radiation produced by the high-power halogen lamp  130  is directed to the wafer W held in the processing chamber under a reduced pressure environment. As represented in FIG. 2 or FIG. 3, the quartz window  120  may include a disc-shaped quartz plate  121  having a diameter of about 400 mm and a thickness of 2-6 mm, wherein the quartz window  120  further includes a rib structure  122  provided on the quartz plate  121  for reinforcing the mechanical strength thereof. FIG. 2 shows the quartz window  120  in a plan view while FIG. 3 shows the quartz window  120  in an elevational cross-sectional view showing a part of the quartz window  120  including the lamp  130  and the reflector  140  in an enlarged scale.  
         [0069]    Referring to FIGS. 2 and 3, the rib structure  122  includes circumferential ribs  124  for reinforcing the mechanical strength of the window  120  in the circumferential direction and radial ribs  126  for reinforcing the mechanical strength in the radial direction, wherein the circumferential ribs  124  are formed with a number of cutouts for providing a passage of the cooling air for cooing a sealed part  136  (FIG. 8) of the lamp  130  where the lamp  130  is sealed against the quartz window  120 . Preferably, the ribs  124  and  126  have a thickness of less than 10 mm, more preferably in the range between 2-6 mm and a height of less than about 10 mm. While the illustrated example shows a construction in which the ribs  122  extend in the direction of the lamp  144 , the present invention is not limited to such a specific construction, and other constructions such as the one in which the ribs  122  extend toward the wafer W or the one in which the ribs  122  are formed on both top and bottom surfaces of the plate  121 , are possible. In the latter cease, the ribs  124  and the ribs  126  may have different sizes.  
         [0070]    By providing the ribs  122 , the quartz plate  121  is improved with regard to resistance against thermal deformation. Thus, there is no need anymore to form a convex surface and the quartz plate  121  can be formed by a flat disc. Such a flat disc is easily formed as compared with the quartz plate having a curved surface. The ribs  122  may be fixed upon the quartz plate  121  by welding or any other means. For example, the ribs  122  may be formed as an integral body with the quartz plate  121 .  
         [0071]    Preferably, the quartz plate  121  and the rib  122  constituting the quartz window  120  have a thickness of 10 mm or less, more preferably in the range of 2-6 mm as noted before, wherein the foregoing thickness is substantially smaller than the thickness of several ten millimeters (30-40 mm) used for conventional quartz window. As a result of the use of such a thin quartz window  120 , the RTP apparatus  100  of the present embodiment can reduce the optical absorption of the thermal radiation produced by the lamp  130 . Thereby, the efficiency of heating the wafer W by the lamp  130  is improved and the desired rapid temperature rise can be achieved at a reduced power consumption. Further, the RTP apparatus  100  of the present embodiment has another advantageous feature of reduced temperature difference between the top surface and the bottom surface of the quartz plate  121 . Associated with the reduced temperature difference, the thermal stress caused in the quartz plate  121  is reduced and the problem of thermal damage applied to the quartz plate  121  and causing a damage therein is reduced. The same applies also to ribs  122 . Further, because of the reduced temperature rise of the quartz window  120  as compared with conventional quartz windows, it is possible to suppress the deposition of various films or reaction byproducts on the quartz window particularly in the case of a deposition process, and the reproducibility of temperature is guaranteed. Further, the frequency of conducting the cleaning process of the processing chamber  110  can be reduced.  
         [0072]    With regard to the lamp  130 , the illustrated example uses a double-ended type lamp, while use of a single-ended type lamp is also possible as will be explained later. Further, the use of a heating wire is also possible. As represented in FIG. 4, a double-ended lamp  130  is a lamp having two interconnection electrodes  132 , while a single ended lamp is a lamp having only one interconnection electrode as in the case of a light bulb. The lamp  130  functions as a heat source heating the substrate W and a halogen lamp may be used conveniently for this purpose. Of course, the lamp  130  of the present invention is not limited to a halogen lamp. It should be noted that the output power of the lamp  130  is determined by a lamp driver  310 , while the lamp driver  310  is controlled by the system controller  300  as will be explained later and supplies an electric power specified by the system controller  300  to the lamp  130 .  
         [0073]    Referring to the oblique view of FIG. 4, it can be seen that the lamp  130  includes two interconnection electrodes  132  and a tubular lamp house  134  therebetween, wherein the lamp house  134  accommodates therein a filament  135  extending between the interconnection electrodes  132 . As noted previously, the electric power to be supplied to the lamp  130  is provided to the interconnection electrodes  132  under control of the system controller  300 . It should be noted that a seal member  136  is provided between the interconnection electrode  132  and the reflector  140 A.  
         [0074]    As represented in FIG. 4, the lamp house  134  includes a vertical tube  134   a  and an arcuate horizontal tube  134   b  bent with regard to the vertical tube  134   a,  wherein the horizontal tube  134   b  is disposed between a pair of adjacent ribs  126 , such as the arcuate ribs  126   a  and  126   b,  forming together generally concentric grooves on the quartz plate  121 . Thereby, it should be noted that it is not always necessary to fill all of the grooves formed between adjacent ribs  126  by the lamp  130  but the lamp  130  may be provided to form an arcuate optical source having a predetermined angle. For example, the lamp  130  may be omitted from the groove between the ribs  126   b  and  126   c  and from the groove between the ribs  126   d  and  126   a.  In this case, the lamp  130  is provided only in the grooves formed between the ribs  126   a  and is  126   b  and between the ribs  126   c  and  126   d.    
         [0075]    In the present embodiment, the lamps  130  are disposed collectively in a generally concentric form in correspondence to the wafer W having a generally circular form. In such a construction, a number of arcuate lamps having a substantially identical radius of curvature are arranged in a circumferential direction and a number of arcuate lamps having different radius of curvature are arranged in the radial direction.  
         [0076]    It should be noted that the present invention does not exclude the use of a straight double-ended type lamp. When using such a straight lamp, it will be necessary to modify the ribs  122  so as to accommodate such straight lamps. However, the use of the arcuate or curved lamp  130  as set forth above is more advantageous as compared with the case of using straight lamps in view of the fact that a straight lamp covers a wide area of the wafer W and further in view of the fact that the straight lamp is disposed so as to cover the areas of the wafer W having different radial diameters and it is difficult to control the temperature of the circular wafer as compared with the case of using a number of arcuate lamps. By using arcuate lamps, it becomes possible to control the temperature easily for each of the concentric regions of the circular wafer. Further, the directivity of the thermal radiation is improved and the efficiency of heating of the wafer is improved also.  
         [0077]    It should be noted that a reflector  140  reflects the radiation of the lamp  130 . The reflector  140  has a generally cylindrical form with a cross-section of generally rectangular shape as represented in FIG. 1. In more detail, the reflector  140  includes a plurality of penetrating holes  142  extending perpendicularly to the plane of the quartz window  120  for accommodating the end part  132  of the lamp  134  and a number of concentric grooves  144  for accommodating the lamp house  134   b.  Further, there is provided, although not illustrated in FIG. 1, a cooling tube inside or outside of the reflector  140 .  
         [0078]    Further, the reflector has a horizontal part  145  facing the tip end of the ribs  122  between a pair of the grooves  144 .  
         [0079]    It should be noted that the reflector  140  may be replaced by the reflector  140 A represented in FIG. 6, wherein the reflector  140 A includes a number of slits  146  in the foregoing horizontal part  145  for accommodating the ribs  122 . It should be noted that FIG. 6 is an enlarged view showing a part of the reflector  140 A.  
         [0080]    In the reflector  140  represented in FIG. 3, it should be noted that the optical path  2  for the thermal radiation emitted from the lamp  130  in an oblique direction to the quartz window plate  121  is larger than the optical path  1  emitted perpendicularly to the plate  121 . Associated therewith, the absorption of the optical becomes larger for the ray traveling along the optical path  2  than the ray traveling along the optical path  1 . Here, it should be noted that FIG. 5 is a cross-sectional view for explaining the effect of the thermal radiation incident to the processing chamber  110  through the quartz window  120 .  
         [0081]    As a result of such a difference in the infrared absorption, there is induced a temperature difference in the quartz window  120  between the quartz plate  121  and the ribs  122 , while such a temperature difference induces a thermal stress in the quartz window  120 , which may result in a cracking particularly between the rib  122  and the quartz plate  121 . While it is possible to eliminate such a cracking by optimizing the thickness of the ribs  122 , it is advantageous to use the reflector  140 A of which construction is represented in FIG. 6.  
         [0082]    Referring to FIG. 6, the reflector  140 A is different from the reflector  140  in the point that there is provided a grove  144 A having a larger depth as compared with the groove  144  and that the slit  122  explained before is provided in the horizontal part  145 . By using the reflector  140 A, the ribs  122  are inserted into the slits  146  formed in the reflector  140 A and the problem of the ribs  122  being irradiated directly by the thermal radiation of the lamp  130  is successfully avoided. Further, the structure of FIG. 6 is advantageous in the point that the air pressure, applied to the quartz window  120  as a result of the pressure difference between the interior of the processing chamber  110  and the atmospheric environment and causing a concaved deformation in the quartz plate  121 , is effectively supported by the engagement of the rib  122  and the slit  146  as represented in FIG. 7. It should be noted that FIG. 7 is an enlarged view of a related part of the reflector  140 A and the quartz window  120 . As a result of such an engagement of the reflector  140 A with the ribs  122 , a reinforcement of the quartz window  120  is also achieved.  
         [0083]    Next, the relationship between the air passage  128  formed in the quartz window  120  and the sealing part  136  of the lamp  130  will be explained with reference to FIGS. 8 and 9.  
         [0084]    Referring to FIG. 8 showing the quartz window  120  in a plan view, it can be seen that a cooling air is caused to flow along the air passage  128 . In FIG. 8, the sealing part  136  of the lamp  130  is designated by a circle.  
         [0085]    [0085]FIG. 9 shows the part including the sealing part  136  of the lamp  130 , wherein it should be noted that the lamp  130  is supplied with a driving electric power at the sealing part  136  provided at the end of the tube constituting the lamp  130 . As represented in FIG. 9, the sealing part  136  is inserted into the penetrating hole  142  in the reflector  140 A, wherein the cooling air penetrates also into the hole  142  and cooling of the sealing part  136  is achieved efficiently. In FIG. 1, the illustration of the construction for introducing the cooling air is eliminated.  
         [0086]    [0086]FIGS. 10 and 11 show the case in which the double-ended type lamp  130  explained heretofore is replaced with a single-ended type lamp  130 A, wherein it can be seen that a number of the single-ended type lamps  130 A are provided in combination with the reflector  140 A. FIG. 10 shows an enlarged part of the quartz window  120  having such single-ended lamps  130 A, while FIG. 11 shows the reflector  140 A in a plan view. It should be noted that the construction of FIGS. 10 and 11 provides excellent directivity and controllability for the thermal radiation emitted by the lamps  130 A.  
         [0087]    Next, the construction of the radiation pyrometer  200  used in the RTP apparatus  100  of FIG. 1 will be described with reference to FIGS. 12 and 13, wherein FIG. 12 shows a part of the processing chamber  110  including the radiation pyrometer  200  in an enlarged view, while FIG. 13 shows the construction of a chopper  230  used in the radiation pyrometer  200  in a plan view. It should be noted that the radiation pyrometer  200  is provided at a side opposite to the lamp  130  with respect to the wafer W so as to avoid incidence of the radiation of the lamp  130  directly to the radiation pyrometer  200 , wherein the present invention does not exclude the case in which the radiation pyrometer  200  is provided at the same side of the lamp  130 .  
         [0088]    It should be noted that the radiation pyrometer  200  is mounted on a bottom part  114  of the processing chamber  110 , wherein the bottom part  114  has an inner surface  114   a  plated with high reflection film such as a gold film and the inner surface  114   a  functions as a reflector. When a black surface is used for the surface  114   a,  it becomes necessary to increase the driving power of the lamp  130  so as to compensate for the absorption loss caused by the bottom part  114  of the processing chamber  110 , while such a construction is contradicts with the requirement of economical operation of the RTP apparatus  100 .  
         [0089]    The bottom part  114  of the processing chamber  110  is provided with a circular penetrating hole  115  and the radiation pyrometer  200  detects the temperature of the wafer W by detecting the infrared radiation emitted from a predetermined area of the wafer W at the bottom surface. The radiation pyrometer  200  includes a transparent rod  210  of quartz or sapphire inserted into the foregoing penetrating hole  115  and a casing  220  covering the bottom end of the transparent rod  210 , wherein the casing  220  accommodates therein a chopper  230  for intermittently interrupting the infrared radiation emitted from the bottom end of the transparent rod  210 . The chopper  230  is rotated by a motor  240  provided at the outside of the casing  220  and the infrared radiation passed through the chopper  230  is detected by a detector  270  provided outside the casing  220 .  
         [0090]    By forming the transparent rod  210  by quartz or sapphire, the rod  210  shows an excellent durability to temperature and maintains an excellent optical property during the use of the RTP apparatus  100 , although the material constituting the rod  210  is not limited to quartz or sapphire. Because of the excellent thermal durability of the rod  210 , it is not necessary to provide a cooling mechanism to the rod  210 , and the RTP apparatus  100  can be formed with a compact size.  
         [0091]    If necessary, the rod  210  may be provided so as to project from the inner surface  114   a  toward the interior of the processing chamber  110 . The rod  210  is sealed in the penetrating hole  115  by a seal ring  190 , and the processing chamber  110  is effectively maintained at a low pressure.  
         [0092]    By providing the rod  210  in the penetrating hole  115 , it becomes possible to guide the infrared radiation incident thereto into the casing  220  without causing substantial loss, and the photodetector  270  cooperating with the rod  210  receives the infrared radiation efficiently. Further, the use of the rod  210  enables a multiple reflection of the infrared radiation between the surface of the chopper  230  and the bottom surface of the wafer W as represented in FIG. 12 by arrows. Further, by providing the rod  210  such that the tip end of the rod is located with a short distance from the rear surface of the wafer W, it becomes possible to measure the temperature of the wafer W with high precision.  
         [0093]    By using the rod  210 , on the other hand, it becomes possible to increase the distance between the wafer W and the casing  220 . Thereby, the heating of the casing  220  is held minimum and no cooling mechanism is necessary. Thus, the use of the rod  210  contributes to the downsizing of the RTP apparatus  100 . Further, even in the case a cooling mechanism is provided to the casing  220 , the use of the rod  210  contributes to the reduction of power consumption of the cooling mechanism.  
         [0094]    It should be noted that the rod  210  may be used together with an optical fiber  210 A as represented in FIG. 24. By providing such an optical fiber  210 A, the optical path of the infrared radiation to be measured becomes flexible and the degree of freedom of designing the radiation pyrometer  200  is increased. Further, it becomes possible to increase the distance between the main body or casing  220  of the radiation pyrometer  200  from the wafer W and the adversary effects caused in the radiation pyrometer  200  by a thermal deformation is eliminated. Thereby, the accuracy of the temperature measurement is improved.  
         [0095]    It should be noted that the casing  220  may have a cylindrical form under the penetrating hole  115 .  
         [0096]    As represented in FIG. 13, the chopper  230  has a disc shaped member disposed generally horizontally with an offset from the center of the penetrating hole  115  and hence the center of the rod  210 . The chopper  230  is connected to a rotary shaft of the motor  240  and is rotated in response to energization of the motor  240 .  
         [0097]    As represented in FIG. 13, the chopper  230  includes quadrant sectors thereon, wherein a high-reflective sector  232  and a low-reflective sector  234  are disposed alternately along the circumferential direction and each of the sectors  232  and  234  carries a slit  231  in correspondence to the optical path of the infrared radiation emitted from the bottom end of the rod  210 . The high-reflective sector  232  may carry a reflective coating such as Al or Au, while the low-reflective sector  234  is provided with a black coating.  
         [0098]    In the chopper  230 , it should be noted that the slit  231  in the high-reflective sector  232  functions as a measuring part  232   a,  while the remaining part of the high-reflective sector  232  functions as an interrupting part  232   b.  Similarly, the slit  232  in the low-reflective sector  234  functions as a measuring part  234   a,  while the remaining part of the low-reflective sector  234  functions as an interrupting part  234   b.    
         [0099]    It should be noted that the construction of the chopper  230  of FIG. 13 is only an example, and various modifications can be made from the construction of FIG. 13. For example, the chopper  230  may include semi-circular high-reflective part and low-reflective part bisecting the surface of the circular chopper  230 , or the surface of the chopper  230  may be divided into more than the foregoing four quadrants. Further, it is possible to provide the slit  231  only in the high-reflective sector of the chopper  230 . Further, the low-reflecting sector  234  may be replaced by a cutout.  
         [0100]    When the chopper  230  is rotated with the rotation of the motor  240 , there appear the high-reflective sector  232  and the low-reflective sector  234  alternately at the bottom end of the rod  210 . Thus, at the instance when the sector  232  is located underneath the rod  210 , the majority of the infrared radiation emitted at the bottom end of the rod  210  is reflected back to the rear surface of the wafer W through the rod  210 . When the sector  234  is located underneath the rod  210 , on the other hand, the majority of the infrared radiation emitted at the bottom end of the rod  210  is absorbed by the low-reflective sector  234 . Thus, the photodetector  270  detects the infrared radiation emitted from the rear surface of the wafer W directly and further the radiation after a multiple reflection between the wafer and the high-reflective sector.  
         [0101]    The detector  270  includes a lens, a Si photocell, an amplifier, and the like, not illustrated, and converts the infrared radiation incident to the lens to an electrical signal indicative of a radiation intensity E 1  (T) or E 2  (T) to be described later, wherein the electrical signal thus produced is supplied to the system controller  300 . The system controller  300 , on the other hand, includes a CPU and a memory and calculates the emissivity ε of the wafer W and the wafer temperature T according to a procedure to be described. This calculation of the temperature can of course be carried out by other arithmetic units in the radiation pyrometer  200  not illustrated.  
         [0102]    In more detail, the infrared radiation passed through the slid  231  is focused by the lens  250  and is guided to the detector  270  via an optical fiber  260 . Thereby, the emission strength (or luminance) at the high-reflective sector  232  is represented as follows:  
                   E   1          (   T   )       =       ɛ     1   -     R        (     1   -   ɛ     )           ×       E     B                 B            (   T   )           ,           (   2   )                               
 
         [0103]    wherein E 1  (T) represents the radiation strength obtained by the detector  270  for the high-reflective surface  232  at the temperature T, while R represents the effective reflectance of the high-reflective surface  232 . Further, ε represents the reflectance of the wafer W and E BB  (T) represents the radiation strength of a black body at the temperature T.  
         [0104]    It should be noted that the foregoing Eq. (2) is derived from the following Eq. (3) assuming that there is no transmittance of the thermal radiation through the wafer W as follows:  
                 E   1          (   T   )       =         ɛ                     E     B                 B            (   T   )         +     ɛ                   R        (     1   -   ɛ     )              E     B                 B            (   T   )         +         ɛ        [     R        (     1   -   ɛ     )       ]       2            E     B                 B            (   T   )         +                …                 ∞       =       ɛ     1   -     R        (     1   -   ɛ     )                    E     B                 B            (   T   )       .                 (   3   )                               
 
         [0105]    Further, it should be noted that the emission strength (or luminance) at the low-reflective sector  234  is represented as follows:  
           E   2 ( T )=ε  E   BB ( T )  (4)  
         [0106]    wherein E 2 (T) represents the emission strength of the low-reflection surface  2347  at the temperature T obtained by the detector  270 . The Eq. (4) is derived from the radiation equation of Planck.  
         [0107]    From Eqs. (2) and (4), the emissivity E is represented as follows:  
             ɛ   =               E   2          (   T   )       /       E   1          (   T   )         +   R   -   1     R     .             (   5   )                               
 
         [0108]    Generally, the spectrum of the electromagnetic radiation emitted by a black body is given by the Planck&#39;s equation, and there holds a relationship between the temperature T of a black body and the emission strength E BB (T) measured by the radiation pyrometer  200  as follows:  
                   E     B                 B            (   T   )       =     C                   exp        (     -       C   2         A                 T     +   B         )           ,           (   6   )                               
 
         [0109]    wherein A, B and C are constants determined by the optical system of the radiation pyrometer  200  while C 2  represents the second constant of radiation.  
         [0110]    The Eq. (6) can be solved with regard to the temperature T and the equation  
             T   =         C   2       A        [       ln                 C     -     ln                     E     B                 B            (   T   )           ]         -     B   A               (   7   )                               
 
         [0111]    is obtained.  
         [0112]    Thus, the emission strength E BB  (T) is obtained by the detector  270  and the system controller  300  based on Eq. (5) and Eq. (2) or (4), and the emission strength E BB  (T) is used in Eq. (7) to  15  obtain the temperature T of the wafer W.  
         [0113]    The temperature T thus obtained based on Eq. (7), however, generally contains an error of about 20-40° C. as represented in FIG. 14 or FIG. 15, and it has been difficult to carry out a high-quality thermal processing with accurately controlled temperature when the conventional radiation pyrometer  200  is used, wherein FIG. 14 shows the relationship between the actual temperature of the wafer W at the central part thereof and the temperature obtained by using the radiation pyrometer  200  together with Eq. (1). Further, FIG. 15 shows the relationship between the actual temperature of the wafer W obtained for the marginal part of the wafer W and the corresponding temperature obtained by the radiation pyrometer  200  while using Eq. (1).  
         [0114]    After diligent investigation in search of the cause of the error, the inventor of the present invention has finally identified several factors that have caused the foregoing error, as represented in FIG. 16.  
         [0115]    More specifically, the rod  210  may be injected with the infrared radiation reflected a number of times between the wafer W and the inner surface  144   a  of the processing chamber as represented by a ray J in FIG. 16. Further, the rod  210  may be injected with the radiation produced by the lamp  130  and has traveled in the processing chamber  110  as a stray light, as represented in FIG. 16 by a ray K.  
         [0116]    Further, the rod  210  itself causes an optical absorption, while such an optical absorption appears as an optical loss M as represented in FIG. 16. Further, reflection at the end surface of the rod  210  may cause another optical loss L as represented in FIG. 16.  
         [0117]    In a single-wafer processing apparatus such as the RTP apparatus  100 , the interior of the processing chamber  110  and other parts provided in the vicinity of the wafer W are provided with a reflective coating for improving the thermal efficiency. Thus, the problem of the multiple reflection J and the stray light K are particularly important in the RTP apparatus  100  of the present invention. As noted above, FIG. 16 is an enlarged cross-sectional diagram of the processing chamber  110  showing the foregoing various cause of the error when determining the temperature by the radiation pyrometer  200 .  
         [0118]    From the foregoing, the inventor of the present invention has reached a conclusion that the foregoing error would be compensated for by modifying Eq. (1) to an equation represented as follows,  
                 E   m          (   T   )       =     G        {       ɛ     1   -     α        (     1   -   ɛ     )           -   β     }          {         E     B                 B            (   T   )       +   S     }               (   8   )                               
 
         [0119]    wherein Eq. (8) compensates for the effect of the multiple reflection J by modifying the emissivity ε to formulate an effective emissivity represented as ε/{1-α (1-ε)} where α is a correction coefficient.  
         [0120]    Further, Eq. (8) compensates for the effect of the stray radiation S by adding a correction term S to E BB (T), wherein the correction term S can be interpreted as representing an additional radiation source that produces the stray radiation. Further, Eq. (8) compensates for the effect of the reflection L at the end of the rod  210  by subtracting a correction term β corresponding to the reflection loss L from the effective emissivity ε/{1-α (1-ε)}. Further, Eq. (8) compensates for the effect of the absorption loss M by multiplying a correction coefficient G (gain coefficient) to the term [ε/{1-α (1-ε)}-β] E BB (T)+S}.  
         [0121]    According to situation, one or more of the correction terms may be omitted in Eq. (8). Eq. (8) may be stored in a computer-readable medium such as a magnetic disk or optical disk, together with a computer program for carrying out the temperature measurement. Further, the computer program including Eq. (8) may be transmitted over a telecommunication network from one site to another side in the form of transactions.  
         [0122]    [0122]FIGS. 17 and 18 show the pyrometer temperature obtained by Eq. (8) and the actually measured temperature of the wafer, wherein FIG. 17 compares the two temperature readings at the center of the wafer W while FIG. 18 compares the two temperature readings at the edge of the wafer W. As can be seen in FIG. 17 or FIG. 18, the deviation between the two temperature readings is maintained within +3° C.  
         [0123]    It should be noted that the system controller  300  includes therein a CPU and a memory and recognizes the temperature T of the wafer W in the RTP apparatus  100 . The system controller  300  then conducts a feedback control of the lamp drive  310  in response to the temperature T. As will be explained later, the system controller  300  further controls the rotation of the wafer W by supplying a driving signal to the motor driver  320  with a predetermined interval.  
         [0124]    It should be noted that the gas inlet  180  includes various associated units not illustrated, such as a gas source, flow control valves, mass flow controllers, a gas supply nozzle, and various conduits interconnecting these units. While the illustrated example use the construction of providing the gas inlet  180  on the sidewall  112  of the processing chamber  110 , the present invention is not limited to such a specific embodiment and the processing gas may be introduced from a shower head provided at the upper part of the processing chamber  110 .  
         [0125]    When the thermal processing conducted in the chamber  110  is an anneal processing, a gas such as N2 or Ar is introduced from the gas inlet into the processing chamber  110 . When an oxidizing process is to be conducted, on the other hand, any of the gases such as O 2  and H 2 , H 2 O or NO 2  may be used. Further, when the processing is a deposition process, gases such as NH 3 , SiH 2 Cl 2 , SiH 4 , and the like, are used. It should be noted that the gases used in the RTP apparatus of the present invention is not limited to such a specific gas.  
         [0126]    It should be noted that the mass flow controller is used for controlling the flow-rate of the gas and may be the type that includes a bridge circuit, an amplifying circuit, a comparator control circuit and a flow-control valve. The mass flow controller of this type controls the flow-control valve by detecting the gas flow-rate based on the measurement of the thermal transfer caused by the gas flow flowing from an upstream side to a down stream side.  
         [0127]    The gas supply system is designed to prevent penetration of impurities from the gas conduit into the gas by using a seamless pipe. Further, a bite type joint or a metal gasket joint is used for the same purpose. Further, in order to eliminate dust particles due to the contamination or corrosion inside the conduit, it is practiced to cover the inner surface of the conduit by an insulating material such as PTFE, PFA, polyimide, PBI, and the like Alternatively, the inner surface of the conduit may be subjected to an electrolytic polishing process. Further, there are cases in which a dust particle trap is provided.  
         [0128]    In the construction of FIG. 1, it should be noted that the exhaust port  190  is provided so as to evacuate the processing chamber  110  in a generally horizontal direction similarly to the gas inlet port  180 . It should be noted that the exhaust port  190  is not limited to such a construction but the exhaust port  190  may be provided at other locations, with two or more numbers. The exhaust port  190  is connected to a suitable evacuation pump such as a turbo molecular pump, a sputter-ion pump, a getter pump, a sorption pump, a cryopump, and the like, via a pressure regulation valve.  
         [0129]    While the processing chamber  110  is maintained under a reduced pressure environment during the process in the present embodiment, the present invention is applicable also to the case in which the processing does not require a reduced pressure environment. For example, the RTP apparatus  100  may be applicable to the processing conducted in the pressure range from 133 Pa to the atmospheric pressure. Further, it should be noted that the exhaust port  190  has further the function of removing the He gas used in the process to be explained with reference to FIGS.  20 - 24  from the processing chamber  110 , before the next process is started.  
         [0130]    [0130]FIG. 19 is a graph representing the result of a simulation conducted with regard to the cooling rate of the wafer W for the RTP apparatus  100  of FIG. 1, wherein the “gap” represented in FIG. 19 indicates the interval between the wafer W and the bottom part  114  of the processing chamber  110 .  
         [0131]    Referring to FIG. 19, it can be seen that the cooling rate increases with decreasing size of the gap and that the cooling rate is increased remarkably when a He gas is supplied to the processing chamber  110  such that the He gas flows between the substrate W and the bottom part  114 .  
         [0132]    It should be noted that the construction of the RTP apparatus  100  of FIG. 1 uses the bottom part  114  acting as a cooling plate at the rear side of the wafer W while heating the wafer W from the top side by the lamp  130 . Thus, the construction of FIG. 1 provides a relatively large cooling rate, while it requires a large electric power for rapid temperature increase due to large heat dissipation. In order to save the electric power at the time of the temperature rise, it is possible to interrupt the supply of the cooling water, while such a process is generally not acceptable due to the problem of decrease of yield of the wafer processing.  
         [0133]    Thus, in order to avoid this problem, it is possible to use a bottom part  114 A represented in FIGS.  20 - 22  in place of the bottom part  114 , wherein the bottom part  140 A is provided movable with respect to the wafer W. Further, a thermal conductive He gas is caused to flow between the wafer W and the bottom part  114 A for enhancing the heat dissipation of the wafer W. It should be noted that FIG. 20 is a schematic cross-sectional view showing the movable construction of the bottom part  114 A with respect to the wafer W, while FIG. 21 shows the positional relationship used in the RTP apparatus  100  between the bottom part  114 A and the wafer W when carrying out a rapid heating of the wafer W. Further, FIG. 22 shows the positional relationship used in the thermal processing apparatus  100  between the bottom part  114 A and the wafer when carrying out a rapid cooling of the wafer W. In the illustration of FIGS.  20 - 22 , the illustration of the radiation pyrometer  200  and the cooling passages  116   a  and  116   b  is omitted for the sake of simplicity.  
         [0134]    As represented in FIG. 20, the illustrated construction uses a bellows for maintaining the reduced pressure environment inside the processing chamber  110 , wherein the bottom part  114 A is moved up and down with respect to the wafer W by an elevating mechanism  117  under control of the system controller  300 . As any available mechanism can be used for the elevating mechanism  117 , further explanation thereof will be omitted. Contrary to the present embodiment, it is also possible to construct the support ring  150  as a movable part, so that the wafer W is moved up and down in the processing chamber  110 .  
         [0135]    Thus, when heating the wafer W, the bottom part  114 A is lowered as represented in FIG. 21 so as to increase the distance between the wafer W and the bottom part  114 A and the supply of the He gas is interrupted. In an example, a distance of about  10  mm is secured between the wafer W and the bottom part  114 A. Because of the large distance between the bottom part  114 A and the wafer W, the thermal influence of the bottom part  114 A on the wafer W is reduced and the temperature of the wafer W is increased rapidly. For example, the state of FIG. 21 may be defined as a home position of the wafer W.  
         [0136]    When cooling the wafer W, on the other hand, the bottom part  114 A is lifted up toward the wafer W so as to reduce the distance therebetween, and the supply of the He gas is started. Because of the small distance between the wafer W and the bottom part  114 A, the wafer W is cooled rapidly as a result of the increased thermal influence of the bottom part  114 A. Typically, a distance of about 1 mm is used between the wafer W and the bottom part  114 A.  
         [0137]    [0137]FIG. 23 shows the introduction of the He gas, wherein FIG. 23 represents the encircled region V of FIG. 22 in an enlarged scale.  
         [0138]    Referring to FIG. 23, the bottom part  114  is provided with a number of minute holes  115   a,  and the He gas is introduced into the space between the rear surface of the wafer W and the bottom part  114  via these minute holes  115   a.  It should be noted that a case  410  having a valve  400  is attached to the bottom part  114  and a gas supply line from a He gas source is connected to the valve  400 .  
         [0139]    It should be noted that the construction of FIGS.  20   22  designed for changing the distance between the wafer W and the bottom part  114  of the processing chamber  110  can be used also for changing the distance between the wafer W and the lamp  130 .  
         [0140]    Hereinafter, the construction for rotating the wafer W will be explained with reference to FIG. 1.  
         [0141]    In order to maintain a high yield in the production of semiconductor devices and integrated circuits and for maintaining a high performance of the individual semiconductor devices, it is required that the wafer W experiences a uniform RTP over the entire surface thereof. When there is a non-uniform temperature distribution on the wafer W, various problems such as non-uniform film thickness or formation of slip dislocation in the silicon crystal caused by a thermal stress, are expected, and the RTP apparatus  100  can no longer provide the high-quality thermal processing.  
         [0142]    Such a non-uniform temperature distribution on the wafer W may be caused by the non-uniform distribution of the radiation of the lamp  130  or may be caused by the thermal effect of the low-temperature processing gas injected into the processing chamber  110  from the gas inlet  180 . In order to eliminate such a non-uniformity of temperature distribution and to guarantee a uniform heating of the wafer W, the RTP apparatus  100  may include a rotating mechanism for rotating the wafer W.  
         [0143]    It should be noted that the rotating mechanism of the W includes, in addition to the support ring  150  and the ring-shaped permanent magnet  170 , a magnetic body  172  attached to the bottom edge of the rotary support member  152 . The magnetic body  172  is provided in a concentric relationship with respect to the permanent magnet  170 , and the permanent magnet  170  is rotated by a motor  330  driven by a driver circuit  320  under control of the system controller  300 . Thus, in response to the rotation of the permanent magnet  170 , the magnetic body  172 , and hence the support ring  150  connected to the magnetic body  172  via the rotary support member  152 , is rotated.  
         [0144]    Typically, the support ring  150  is formed of a refractory ceramic material such as SiC and is formed to have a ring-shape. As noted previously, the support ring  150  functions as a stage of the wafer W and has a central cutout exposing the rear surface of the wafer W. As the central cutout has a diameter smaller than the outer diameter of the wafer W, the support ring  150  can support the wafer W thereon by engaging with a peripheral edge part of the wafer W. If necessary, the support ring  150  may carry a clamp mechanism or an electrostatic chuck for holding the wafer W firmly. By using the support ring  150 , it becomes possible to prevent the deterioration of temperature profile caused by thermal radiation at the peripheral edge part of the wafer W.  
         [0145]    As noted previously, the support ring  150  carries the rotary support member  152  connected to a peripheral edge part thereof, wherein the rotary support member  152  is connected to the peripheral edge part of the support ring  150  via a thermal insulating member such as a quartz glass such that the magnetic body  172  is thermally protected. In the illustrated example, the rotary support member  152  is formed of a cylindrical sleeve of a devitrified quartz glass.  
         [0146]    Between the rotary support member  152  and the sidewall  112  of the processing chamber  110 , there is provided a bearing mechanism  160  for allowing free rotation of the rotary support member  152  in the state that the processing chamber  110  is evacuated to a high vacuum state, wherein the bearing mechanism  160  is fixed upon the inner surface of the sidewall  112 . As noted already, the magnetic body  172  is provided at the bottom edge of the rotary support member  152 .  
         [0147]    As noted previously, the ring-shaped permanent magnet  170  and the magnetic body  172  are provided in a concentric relationship, wherein the permanent magnet  170  and the magnetic body  172  achieves a magnetic coupling via the sidewall  112  of the processing chamber  112 , which is typically formed of a non-magnetic material such as Al. Thus, the magnetic body  172  undergoes rotation in response to a rotation of the magnet  170 , which is driven by the motor driver circuit  320  via the motor  330  under control of the system controller  300 . Thereby, the rotational speed is determined in view of the material and size of the wafer W and further in view of the gas atmosphere and temperature in the processing chamber  110  so as to avoid turbulence of the atmosphere in the processing chamber  110 , particularly in the peripheral part of the wafer W. In the illustrated example, the support ring  150  is rotated at a rotational speed of 90 RPM. It should be noted that it is possible to use a magnetic material for the magnet  170  and a permanent magnet for the magnetic material  172 , as long as they are magnetically coupled. Further, both of the members  170  and  172  may be formed of a permanent magnet.  
         [0148]    Next, the operation of the RTP apparatus  100  will be explained.  
         [0149]    First, the wafer W is incorporated into the processing chamber  110  by a transportation means such as a transportation arm of a cluster tool not illustrated via a gate valve of the processing chamber  110  not illustrated. When the arm carrying the wafer W has reached the top part of the support ring  150 , a number of lifter pins (typically three) are moved upward from the support ring  150  and engages with the rear surface of the wafer W. In this state, the arm is retracted through the gate valve, and the gate valve is closed. The transportation arm may thereafter return to its home position not illustrated.  
         [0150]    Next, the lifter pins are retracted into the support ring  150  and the wafer W is held on a predetermined position of the support ring  150 . The driving of the lifter pins may be achieved by using a bellows not illustrated so as to maintain the evacuated, low-pressure environment in the processing chamber  110  and so as to avoid leakage of the atmosphere in the processing chamber  110  into the atmospheric environment.  
         [0151]    Thereafter, the system controller  300  controls the lamp driver  310  so as to energize the high-power lamp  130 . In response thereto, the lamp driver  310  energizes the lamp  130  and the wafer W is heated to a temperature of about 800° C.  
         [0152]    More specifically, the infrared radiation emitted by the lamp  130  illuminates the top surface of the wafer W and the temperature of the wafer W is increased rapidly to the foregoing temperature of 800° C. with a rate of 200° C./s. While there is a general tendency that the marginal part of the wafer W has a large heat dissipation rate as compared with the central part thereof, the present invention can successfully compensate for the appearance of non-uniform temperature profile by providing the lamp  130  in the form of a number of concentric lamp elements and by energizing the lamp elements independently.  
         [0153]    During this phase of rapid temperature rise, the bottom part  114 A is set to the home position represented in FIG. 21, provided that the construction of FIG. 20 is used. It should be noted that the state of FIG. 21 is particularly advantageous for rapid temperature rise due to the increased distance of the bottom part  114 A acting as a cooling plate from the wafer W. Simultaneously to the heating, the evacuation system  190  is driven so as to maintain the reduced pressure environment in the processing chamber  110 .  
         [0154]    During the foregoing phase of rapid temperature rise, the system controller  300  controls the motor drive  320  so as to drive the motor  330  at a predetermined, optimum speed. In response, the motor  330  is energized and the ring-shaped magnet  170  is rotated with the foregoing optimum speed. As a result of the rotation of the magnet  170 , the support member  152  is rotated together with the support ring  150  and the wafer W placed thereon. As a result of the rotation of the wafer W, the temperature in the wafer W is maintained uniform during the interval of the rapid thermal processing.  
         [0155]    Because the relatively small thickness of the quartz plate  121  constituting the quartz window  120 , various advantages such as: (1) decreased absorption of the radiation emitted by the lamp  130 ; (2) reduced thermal stress induced in the quartz plate  121  because of reduced temperature difference between the top surface and the bottom surface; (3) reduced deposition of films or byproducts on the surface of the quartz plate during a deposition process due to reduced temperature of the quartz plate  121 ; (4) sufficient mechanical strength reinforced by the ribs  122  for sustaining the air pressure difference between the atmospheric pressure and the low-pressure inside the processing chamber  110 , even in the case the thickness of the quartz plate  121  is thus reduced; (5) reduced temperature rise of the ribs  122 , provided that the construction of FIG. 6 in which the ribs  122  are inserted into the corresponding grooves  146  of the reflector  140 A is used, and resultant decrease of thermal stress at the junction part where the quartz plate  121  and the ribs  122  are connected; and (6) further improved resistance of the quartz window with regard to the pressure difference between the atmospheric environment and the interior of the processing chamber  110 , provides the the construction of FIG. 6 is used.  
         [0156]    The temperature of the wafer W is measured by the radiation pyrometer  200  and the system controller  300  carries out a feedback control of the lamp driver  310  based on the temperature reading of the radiation pyrometer  200 . While it is generally expected that a uniform temperature distribution is realized in the wafer W due to the rotation of the wafer W, it is also possible to provide the radiation pyrometer  200  at a plurality of locations such as the center and peripheral edge of the wafer W, if necessary. In such a case, it becomes possible to modify the energization of the lamp  130  locally via the lamp drive  310  when it is judged that the temperature distribution in the wafer W is not uniform.  
         [0157]    In the present invention, it should be noted that the distance between the wafer W in the processing chamber  110  and the chopper  230  in the radiation pyrometer  200  is increased as a result of the use of the rod  210 , and the adversary thermal influence of the wafer W on the radiation pyrometer  200  is minimized. Thus, the construction of the present invention improves the accuracy of the radiation pyrometer  200 . Further, because of the increased distance between the wafer w and the chopper  230 , it is not necessary at all to provide a cooling mechanism to the radiation pyrometer  200  or it is sufficient to provide only a simple cooling system. Thereby the cost and size of the RTP apparatus  100  are reduced.  
         [0158]    In view of the possibility of extensive diffusion of impurity elements taking place in the wafer W when the wafer W is plated in a high temperature environment over a prolonged duration and resultant deterioration of the performance of the semiconductor devices and integrated circuits formed therein, the use of the radiation pyrometer  200  is particularly useful for realizing an RTP apparatus in which a rapid temperature rise and rapid temperature drop are achieved under feedback control. Particularly, the error of temperature reading of the radiation pyrometer  200  is suppressed within +3° C. by using Eq. (8) in the pyrometer  200  or in the system controller  300  for the temperature calculation. Thereby, a high-quality temperature control is realized.  
         [0159]    After the foregoing phase of rapid temperature rise, a processing gas is introduced into the processing chamber  110  from a gas inlet with controlled flow-rate.  
         [0160]    After a predetermined interval such as 10 seconds for the thermal processing, the system controller  300  controls the driver  310  and terminates the energization of the lamp  130 . In response thereto, the lamp driver  310  interrupts the supply of the driving power to the lamp  130 .  
         [0161]    In this rapid cooling phase, the system controller  300  controls the elevating mechanism  117 , in the case the RTP apparatus  100  has the construction of FIG. 20, such that the bottom part  114 A is lifted up to the cooling position as represented in FIG. 23. Further, a thermal conductive gas such as He is introduced into the gap between the wafer W and the bottom part  114 A as represented in FIG. 23 for facilitating the cooling of the wafer W. With this, it becomes possible to achieve a cooling rate of as large as 200° C./sec.  
         [0162]    After the foregoing thermal processing, the wafer W is taken out from the processing chamber  110  through the gate valve by the transportation art in a reverse procedure noted before. If necessary, the transportation arm further transfers the wafer W thus processed to a next stage processing apparatus, which may be a deposition apparatus.  
         [0163]    Further, the present invention is not limited to the embodiments described heretofore but various variations and modifications may be made without departing from the scope of the invention.