Abstract:
A method of manufacturing a semiconductor device by processing a wafer, comprises: measuring a reflectivity of a substrate peripheral structure before heating, the substrate peripheral structure being placed close to the wafer and being heated simultaneously with the wafer by a plurality of heat sources; measuring a wafer reflectivity of the wafer before the heating; calculating a wafer emissivity of the wafer from the wafer reflectivity; measuring a wafer radiation intensity of radiation emitted from the wafer during the heating; calculating a wafer temperature of the wafer from the wafer emissivity and the wafer radiation intensity; calculating a target value of on-wafer optical intensity on the wafer so that the wafer temperature becomes a preset temperature; calculating a target value of optical intensity on the substrate peripheral structure from a difference between the reflectivity of the substrate peripheral structure and the wafer reflectivity so that incident light being incident on the substrate peripheral structure and wafer incident light being incident on the wafer have an equal optical intensity; calculating target values of heat source optical intensity for heating by the heat sources so that the target value of on-wafer optical intensity and the target value of optical intensity of the substrate peripheral structure are achieved; calculating target values of heat source power so that the target values of heat source optical intensity are achieved; and inputting the target values of heat source power to the plurality of heat sources and causing the heat sources to emit light.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2005-265849, filed on Sep. 13, 2005; the entire contents of which are incorporated herein by reference  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to a method and apparatus for manufacturing a semiconductor device by using lamps to heat a wafer having semiconductor devices thereon.  
         [0004]     2. Background Art  
         [0005]     In an apparatus for manufacturing a semiconductor device by using lamps to heat a wafer having semiconductor devices thereon, the lamps are placed at the backside of the wafer where the semiconductor devices are not located. At the frontside of the wafer, radiation thermometers are placed for measuring radiation emitted from the wafer (see, e.g., JP2001-274109A). The radiation intensity of radiation emitted from the wafer is measured by the radiation thermometers, and the temperature of the wafer is determined from the radiation intensity. Electric power supplied to the lamps is adjusted on the basis of this wafer temperature.  
         [0006]     However, despite using radiation thermometers, the emissivity may be nonuniform within the wafer, or within the region including the wafer where the heating temperature should be uniform. In these cases, the temperature within the wafer becomes nonuniform, and the resulting semiconductor devices may have nonuniform characteristics within the wafer, thereby becoming a cause of decreased semiconductor device yields.  
       SUMMARY OF THE INVENTION  
       [0007]     According to an aspect of the invention, there is provided a method of manufacturing a semiconductor device by processing a wafer, comprising: measuring a reflectivity of a substrate peripheral structure before heating, the substrate peripheral structure being placed close to the wafer and being heated simultaneously with the wafer by a plurality of heat sources; measuring a wafer reflectivity of the wafer before the heating; calculating a wafer emissivity of the wafer from the wafer reflectivity; measuring a wafer radiation intensity of radiation emitted from the wafer during the heating; calculating a wafer temperature of the wafer from the wafer emissivity and the wafer radiation intensity; calculating a target value of on-wafer optical intensity on the wafer so that the wafer temperature becomes a preset temperature; calculating a target value of optical intensity on the substrate peripheral structure from a difference between the reflectivity of the substrate peripheral structure and the wafer reflectivity so that incident light being incident on the substrate peripheral structure and wafer incident light being incident on the wafer have an equal optical intensity; calculating target values of heat source optical intensity for heating by the heat sources so that the target value of on-wafer optical intensity and the target value of optical intensity of the substrate peripheral structure are achieved; calculating target values of heat source power so that the target values of heat source optical intensity are achieved; and inputting the target values of heat source power to the plurality of heat sources and causing the heat sources to emit light.  
         [0008]     According to other aspect of the invention, there is provided a method of manufacturing a semiconductor device by processing a wafer, the wafer being simultaneously heated by a plurality of upside heat sources placed at a frontside of the wafer and by a plurality of downside heat sources placed at a backside of the wafer, the method comprising: measuring a central reflectivity of a central portion of the backside of the wafer and a reflectivity of an outer peripheral portion of the backside before the heating; calculating a central emissivity of the wafer from the central reflectivity; measuring a central radiation intensity of radiation emitted from the central portion during the heating; calculating a central temperature of the central portion from the central emissivity and the central radiation intensity; calculating a target value of central optical intensity on the central portion so that the central temperature becomes a preset temperature; calculating a target value of optical intensity on the outer peripheral portion from a difference between the reflectivity of the outer peripheral portion and the central reflectivity so that incident light being incident on the outer peripheral portion and central incident light being incident on the central portion have an equal optical intensity; calculating a plurality of target values of downside heat source optical intensity for heating by the plurality of downside heat sources, respectively, so that the target value of central optical intensity and the target value of outer peripheral optical intensity are achieved; calculating a plurality of target values of upside heat source optical intensity for heating by the plurality of upside heat sources, respectively, so that the plurality of target values of downside heat source optical intensity have a smaller difference; calculating target values of downside heat source power so that the target values of downside heat source optical intensity are achieved; calculating target values of upside heat source power so that the target values of upside heat source optical intensity are achieved; inputting the target values of downside heat source power to the plurality of downside heat sources and causing the downside heat sources to emit light; and inputting the target values of upside heat source power to the plurality of upside heat sources and causing the upside heat sources to emit light.  
         [0009]     According to other aspect of the invention, there is provided an apparatus for manufacturing a semiconductor device comprising: a plurality of heat sources which emit light with an inputted heat source power and heating a uniform heating temperature region including a wafer; an input unit which inputs reflectivity at a plurality of positions in the uniform heating temperature region, the reflectivity being measured before the heating; an emissivity calculation unit which calculates emissivity of the uniform heating temperature region from the reflectivity; an optical intensity measuring unit which measures radiation intensity of radiation emitted from the uniform heating temperature region during the heating; a temperature calculation unit which calculates a heating temperature of the uniform heating temperature region from the emissivity and the radiation intensity; an optical intensity calculation unit which calculates a target value of on-region optical intensity on the uniform heating temperature region so that the heating temperature becomes a preset temperature; a correction unit which corrects the target value of on-region optical intensity using a difference in reflectivity among the plurality of positions so that incident light being incident on the uniform heating temperature region has a uniform optical intensity; an optical intensity calculation unit which calculates a target value of optical intensity for heating by the plurality of heat sources so that the target value of on-region optical intensity is achieved; a power calculation unit which calculates a target value of heat source power so that the target value of heat source optical intensity is achieved; and a power supply unit which supplies heat source power at the target value of heat source power to the lamps. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a configuration diagram of a semiconductor device manufacturing system according to one embodiment of the invention.  
         [0011]      FIG. 2  is a flow chart of a method of manufacturing a semiconductor device according to one embodiment of the invention.  
         [0012]      FIG. 3  shows a bottom view ( FIG. 3A ) and a cross-sectional view ( FIG. 3B ) of a first set of measurement points for measuring the reflectivity of the substrate peripheral structure.  
         [0013]      FIG. 4  shows a bottom view ( FIG. 4A ) and a cross-sectional view ( FIG. 4B ) of measurement points for measuring the reflectivity of the wafer.  
         [0014]      FIG. 5  shows a first reflectivity profile ( FIG. 5B ) in the uniform heating temperature region ( FIG. 5A ).  
         [0015]      FIG. 6  shows a bottom view ( FIG. 6A ) and a cross-sectional view ( FIG. 6B ) of a second set of measurement points for measuring the reflectivity of the substrate peripheral structure.  
         [0016]      FIG. 7  shows a second reflectivity profile ( FIG. 7B ) in the uniform heating temperature region ( FIG. 7A ).  
         [0017]      FIG. 8  is a first layout diagram of a semiconductor device manufacturing apparatus according to one embodiment of the invention.  
         [0018]      FIG. 9  is a layout diagram of upside halogen lamps in the semiconductor device manufacturing apparatus according to one embodiment of the invention.  
         [0019]      FIG. 10  is a layout diagram of downside halogen lamps in the semiconductor device manufacturing apparatus according to one embodiment of the invention.  
         [0020]      FIG. 11  is a second layout diagram of a semiconductor device manufacturing apparatus according to one embodiment of the invention.  
         [0021]      FIG. 12  is a third layout diagram of a semiconductor device manufacturing apparatus according to one embodiment of the invention.  
         [0022]      FIG. 13  is a layout diagram of upside and downside halogen lamps in the semiconductor device manufacturing apparatus according to one embodiment of the invention.  
         [0023]      FIG. 14  shows an intensity distribution diagram for radiation from the downside halogen lamps ( FIG. 14A ) and a backside temperature profile, an emissivity profile, a reflectivity profile, and a lamp power profile ( FIG. 14B ), for the semiconductor device manufacturing apparatus according to one embodiment of the invention.  
         [0024]      FIG. 15  shows an intensity distribution diagram for radiation from the upside and downside halogen lamps ( FIG. 15A ) and a backside temperature profile, an emissivity profile, a reflectivity profile, and a lamp power profile of the downside halogen lamps ( FIG. 15B ), for the semiconductor device manufacturing apparatus according to one embodiment of the invention.  
         [0025]      FIG. 16  shows a lamp power profile of the upside halogen lamps ( FIG. 16A ), an intensity distribution diagram for radiation from the upside and downside halogen lamps ( FIG. 16B ), and a backside temperature profile, an emissivity profile, and a reflectivity profile ( FIG. 16C ), for the semiconductor device manufacturing apparatus according to one embodiment of the invention.  
         [0026]      FIG. 17  shows a lamp power profile of the upside halogen lamps ( FIG. 17A ), an intensity distribution diagram for radiation from the upside and downside halogen lamps ( FIG. 17B ), and a backside temperature profile, an emissivity profile, a reflectivity profile, and a lamp power profile of the downside halogen lamps ( FIG. 17C ), for the semiconductor device manufacturing apparatus according to one embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]     Embodiments of the invention will now be described with reference to the drawings, which are intended for illustration purposes only and not to be construed as limiting the scope of the invention. In the description of the figures, like or similar elements are marked with like or similar reference numerals. It should be noted that the figures are schematic. The relation of the thickness to the planar dimension and the ratio of thickness between various layers may be different from reality.  
       FIRST EXAMPLE  
       [0028]     As shown in  FIG. 1 , a semiconductor device manufacturing system  1  according to the first example includes a reflectivity (emissivity) measuring apparatus  2  and a semiconductor device manufacturing apparatus  3 . The semiconductor device manufacturing apparatus  3  includes a control unit  4 , an optical intensity measuring unit  5 , a power supply unit  6 , a group of halogen lamps U 1  to U 10 , D 1  to D 10 , a wafer rotation unit  8 , and a rotation control unit  9 . The control unit  4  includes an input unit  11 , a storage unit  12 , an emissivity (reflectivity) calculation unit  13 , a temperature calculation unit  14 , an on-substrate optical intensity calculation unit  15 , an optical intensity correction unit  16 , a lamp optical intensity calculation unit  17 , a power calculation unit  18 , and an output unit  19 .  
         [0029]     A method of manufacturing a semiconductor device according to the first example is carried out using the semiconductor device manufacturing system  1  of  FIG. 1 . As shown in  FIG. 2 , the method of manufacturing a semiconductor device according to the first example begins in step S 1 , where the reflectivity (emissivity) measuring apparatus  2  measures reflectivity at multiple points in the uniform heating temperature region including the wafer backside. This reflectivity measurement is carried out before the heat treatment of the wafer. The reflectivity measurement is performed in two steps. In the first step S 1 - 1 , as shown in  FIGS. 3A and 3B , the reflectivity (emissivity) measuring apparatus  2  measures reflectivity at a plurality of measurement points P 11  to P 14  on the backside of the substrate peripheral structure  23 . The reflectivity at measurement points P 11  to P 14  can be measured before the heat treatment of the wafer if there is no temporal variation. For example, the measurement can be made before introducing the substrate peripheral structure  23  into the heat treatment chamber. The reflectivity (emissivity) measuring apparatus  2  includes an integral sphere  21  and a controller  22  for the integral sphere  21 . The reflectivity (emissivity) measuring apparatus  2  uses the integral sphere  21  to measure reflectivity at a plurality of measurement points P 11  to P 14 .  
         [0030]     The substrate peripheral structure  23  is warmed to the same temperature as the wafer during heat treatment so that the temperature of the wafer during heat treatment is made uniform within the wafer. The wafer in combination with the substrate peripheral structure  23  warmed to the same temperature as the wafer is referred to as a uniform heating temperature region. As shown in  FIGS. 3A and 3B , for the purpose of preventing the temperature on the outer periphery of the wafer  24  from decreasing during heat treatment, a substrate peripheral structure  23  of a ring-shaped silicon carbide (SiC) plate is placed at a position several millimeters away from the edge of the wafer  24 . Alternatively, a substrate peripheral structure  23  of a silicon carbide ring is placed at a position in contact with the outer periphery of the backside of the wafer  24 . The contact situation will be described in more detail with reference to  FIGS. 6 and 7 .  
         [0031]     In the second step S 1 - 2 , as shown in  FIGS. 4A and 4B , the reflectivity (emissivity) measuring apparatus  2  measures reflectivity at a plurality of measurement points P 1  to P 9  on the backside of the wafer  24 . The reflectivity at measurement points P 1  to P 9  is measured for each wafer  24  before lamp heating. This measurement can be made before transferring the wafer into the heat treatment chamber. The reflectivity (emissivity) measuring apparatus  2  can be the same as the apparatus used in step S- 1 .  
         [0032]     The reflectivity of the backside of the wafer  24  may be nonuniform within the wafer for reasons described below. The first reason is the film growth step for growing films on the backside of the semiconductor substrate  25 . As shown in  FIG. 4B , the wafer  24  has a backside film  26  provided on the backside of the semiconductor substrate  25 . The film growth step in the semiconductor device manufacturing method may include film growth techniques such as chemical vapor deposition (CVD), plasma CVD, and sputtering. In the CVD technique, a backside film  26  having a uniform film thickness is grown across the backside of the semiconductor substrate  25 . In the latter two techniques, plasma CVD and sputtering, a backside film  26  is grown on the outer periphery of the backside of the semiconductor substrate  25 , but not grown inside the outer periphery of the backside. Thus the backside film  26  grown on the backside of the semiconductor substrate  25  is nonuniform within the wafer  24 . As a result, the reflectivity of the backside of the wafer  24  may be nonuniform within the wafer.  
         [0033]     The second reason is the processing step in the semiconductor device manufacturing method. The processing step may include anisotropic dry etching, isotropic dry etching, batch wet etching, and single-wafer wet etching. The first technique, anisotropic dry etching, does not etch the backside film  26 . The third technique, batch wet etching, uniformly etches the backside film  26 . Thus these two techniques are free from within-wafer nonuniformity of reflectivity on the backside of the wafer  24 . On the other hand, in the second technique, isotropic dry etching, and the fourth technique, single-wafer wet etching, the outer periphery of the backside film  26  is etched by plasmas or chemicals extending into the outer periphery on the backside of the semiconductor substrate  25 . Thus the reflectivity of the backside of the wafer  24  becomes nonuniform within the wafer. Furthermore, the first reason and the second reason may be combined to increase the within-wafer nonuniformity of reflectivity on the backside of the wafer  24 .  
         [0034]     In step S 2  of  FIG. 2 , the input unit  11  in  FIG. 1  inputs the preset temperature or preset temperature profile of the wafer  24  during heat treatment.  
         [0035]     In step S 3 , the storage unit  12  stores the preset temperature or preset temperature profile.  
         [0036]     In step S 4 , the input unit  11  inputs the measured reflectivity at multiple points in the uniform heating temperature region (on the backside of the substrate peripheral structure  23  and the wafer  24 ). Thus, as shown in  FIGS. 5A and 5B , reflectivities at measurement points P 1  to P 9 , P 11  to P 14  in the uniform heating temperature region  27  are smoothly connected by leveling or other techniques to produce a reflectivity profile  30 , which is a within-wafer distribution of reflectivity in the uniform heating temperature region  27 .  
         [0037]     As shown in  FIG. 6 , the substrate peripheral structure  23  may be a wafer support for supporting the wafer  24 . The wafer support  23  is also warmed to the same temperature as the wafer  24  during heat treatment so that the temperature of the wafer  24  during heat treatment is made uniform within the wafer. The wafer support  23  has wafer supporting pins  28 , which are in contact with the wafer  24 . This is because, when the temperature of the wafer support  23  is lower than that of the wafer  24 , heat flows from the wafer  24  to the wafer support  23  via the wafer supporting pins  28  and prevents the temperature within the wafer  24  from achieving uniformity. The wafer  24  and the wafer support or substrate peripheral structure  23  warmed to the same temperature as the wafer  24  constitute a uniform heating temperature region  27 . The reflectivity (emissivity) measuring apparatus  2  uses the integral sphere  21  to measure reflectivity at a plurality of measurement points P 11  to P 18 , P 21  to P 28  on the backside of the wafer support  23 . The input unit  11  inputs the reflectivity measured at a plurality of measurement points P 1  to P 9 , P 11  to P 18 , P 21  to P 28  in the uniform heating temperature region  27  as shown in  FIG. 7A . Thus, as shown in  FIG. 7B , reflectivities at all the measurement points P 1  to P 9 , P 11  to P 18 , P 21  to P 28  including P 1  to P 5 , P 11 , P 13 , P 21 , P 23  in the uniform heating temperature region  27  are smoothly connected by leveling or other techniques to produce a reflectivity profile  30 , which is a within-wafer distribution of reflectivity in the uniform heating temperature region  27 .  
         [0038]     Next, in step S 5  of  FIG. 2 , the storage unit in  FIG. 1  stores the reflectivities at the measurement points P 11  to P 18 , P 21  to P 28  of the substrate peripheral structure  23 .  
         [0039]     In step S 6 , the emissivity (reflectivity) calculation unit  13  uses the reflectivity profile  30  to calculate emissivity at each of single or multiple radiation intensity measurement points where radiation intensity is to be measured in the next step S 7 . The calculation of emissivity is carried out once for each wafer  24 . If, in step S 1 , emissivity can be measured by the reflectivity (emissivity) measuring apparatus  2 , then in step S 6 , an emissivity profile  30  produced in step S 4  is used to calculate reflectivity and produce a reflectivity profile. If the semiconductor substrate  25  is a silicon (Si) substrate, the relation that the sum of reflectivity and emissivity equals unity holds at heat treatment temperatures such as above 400° C. Therefore once one of reflectivity and emissivity is measured, the other can be easily calculated from this relation.  
         [0040]     In step S 7 , as shown in  FIG. 8 , the wafer  24  and the substrate peripheral structure  23  are transferred into the heat treatment chamber  29  of the semiconductor device manufacturing apparatus  3 . Upside lamps U 1  to U 10  are placed above the heat treatment chamber  29  at the frontside of the wafer  24  and the substrate peripheral structure  23 . As shown in  FIG. 9 , the upside lamps U 1  to U 10  are placed in concentric regions composed of an upside central zone  31 , an upside inner peripheral zone  32 , and an upside outer peripheral zone  33 , and can be supplied with different levels of electric power for respective zones  31  to  33 . Naturally, depending on the situation, different levels of electric power may be supplied to each of the upside lamps U 1  to U 10 . On the other hand, as shown in  FIG. 8 , downside lamps D 1  to D 10  are placed below the heat treatment chamber  29  at the backside of the wafer  24  and the substrate peripheral structure  23 . As shown in  FIG. 10 , the downside lamps D 1  to D 10  are placed in concentric regions composed of a downside central zone  34 , a downside inner peripheral zone  35 , and a downside outer peripheral zone  36 , and can be supplied with different levels of electric power for respective zones  34  to  36 . Naturally, depending on the situation, different levels of electric power may be supplied to each of the downside lamps D 1  to D 10 . As mentioned earlier, as shown in  FIG. 8 , the reflectivity d 1  at multiple points and the preset temperature d 2  have been inputted to the control unit  4 . The separation into the upside central zone  31 , upside inner peripheral zone  32 , and upside outer peripheral zone  33 , and into the downside central zone  34 , downside inner peripheral zone  35 , and downside outer peripheral zone  36 , is not limited to the concentric configuration. The reflectivity profile  30  of  FIG. 5B  or  7 B can be referred to for separation into high-reflectivity and low-reflectivity regions based on the magnitude of reflectivity.  
         [0041]     The upside lamps U 1  to U 10  and the downside lamps D 1  to D 10  emit light, and the wafer  24  and the substrate peripheral structure  23  are irradiated with the lamp light. The wafer  24  and the substrate peripheral structure  23  are thus heated and emit radiation. As shown in  FIG. 8 , an optical intensity measuring unit  5   c  is placed in the downside central zone  34 . An optical intensity measuring unit  5   m  is placed in the downside inner peripheral zone  35 . An optical intensity measuring unit  5   e  is placed in the downside outer peripheral zone  36 . The optical intensity measuring units  5   c ,  5   m , and  5   e  measure radiation intensities d 3   c , d 3   m , and d 3   e  at multiple radiation intensity measurement points on the backside of the wafer  24  and the substrate peripheral structure  23 .  
         [0042]     Note that, as shown in  FIG. 11 , the optical intensity measuring unit  5  may be a single optical intensity measuring unit  5   c . The radiation intensity d 3   c  at a single radiation intensity measurement point can be used to calculate temperature at a single radiation intensity measurement point.  
         [0043]     Furthermore, as shown in  FIGS. 12 and 13 , the upside lamps U 1  to U 10  and the downside lamps D 1  to D 10  may be linear light sources instead of the point light sources in  FIGS. 9 and 10 . Linear light sources of the upside lamps U 1  to U 10  are arranged in the vertical direction, and linear light sources of the downside lamps D 1  to D 10  are arranged in the horizontal direction, orthogonal to the vertical direction. When the upside lamps U 1  to U 10  and the downside lamps D 1  to D 10  are linear light sources, the semiconductor device manufacturing apparatus  3  further includes a rotation unit  8  and a rotation control unit  9 . The rotation unit  8  and the rotation control unit  9  can be used to rotate the wafer  24  and the substrate peripheral structure  23  around a rotation axis, which is the line passing through the center of the wafer  24  and being perpendicular to the backside of the wafer  24 . This allows the optical intensity of light, which irradiates the wafer  24  and the substrate peripheral structure  23  by the upside lamps U 1  to U 10  and the downside lamps D 1  to D 10 , to be varied in the radial direction of the wafer  24 .  
         [0044]     In step S 8  of  FIG. 2 , the input unit  11  in  FIG. 1  inputs the radiation intensities d 3   c , d 3   m , and d 3   e  at multiple points on the backside of the wafer  24  and the substrate peripheral structure  23  from the optical intensity measuring units  5   c ,  5   m , and  5   e.    
         [0045]     In step S 9 , the rotation unit  8  and the rotation control unit  9  may rotate the wafer  24  and the substrate peripheral structure  23 . In order to improve the temperature distribution of the wafer  24 , rotation may be carried out not only when the upside lamps U 1  to U 10  and the downside lamps D 1  to D 10  are linear light sources but also when they are point light sources.  
         [0046]     In step S 10 , the temperature calculation unit  14  uses the calculated emissivity or emissivity profile and the measured radiation intensities d 3   c , d 3   m , and d 3   e  to calculate backside temperature at each of single or multiple radiation intensity measurement points. Alternatively, the temperature calculation unit  14  uses the calculated emissivity profile and the measured radiation intensities d 3   c , d 3   m , and d 3   e  to calculate backside temperature at each irradiation point of the downside lamps D 1  to D 10  and a backside temperature profile.  
         [0047]     In step S 11 , the on-substrate optical intensity calculation unit  15  calculates the target value of on-substrate optical intensity at single or multiple radiation intensity measurement points so that the temperature at each of single or multiple radiation intensity measurement points becomes the uniform preset temperature.  
         [0048]     In step S 12 , the optical intensity correction unit  16  corrects the target value of on-substrate optical intensity at multiple radiation intensity measurement points or at on-substrate irradiation points of the lamps so that the light incident on the uniform heating temperature region  27  becomes uniform even when reflectivity is varied or fluctuated in the uniform heating temperature region  27 .  
         [0049]     In step S 13 , the lamp optical intensity calculation unit  17  calculates the target value of lamp optical intensity for lamp emission so that the target value of the corrected on-substrate optical intensity is achieved.  
         [0050]     In step S 14 , the power calculation unit  18  calculates the lamp power value (d 4  in  FIG. 8  etc.), or a profile of the lamp power value, as shown in  FIG. 14B , for each of the downside lamps D 1  to D 10  so that the target value of lamp optical intensity is achieved.  
         [0051]     In step S 15 , the output unit  19  outputs the lamp power value d 4  to the power supply unit  6 .  
         [0052]     In step S 16 , the power supply unit  6  supplies each of the downside lamps D 1  to D 10  with lamp power corresponding to the lamp power value d 4 .  
         [0053]     In step S 17 , the downside lamps D 1  to D 10  receive lamp power and emit radiation  40  as shown in  FIG. 14A . In the wafer  24 , the thickness of the backside film  26  is uniform at the center but decreased in the outer periphery with the distance from the center. Thus, as shown in  FIG. 14B , the emissivity in the outer periphery of the backside of the wafer  24  is lower than at the center, the reflectivity in the outer periphery of the backside of the wafer  24  is higher than at the center, and hence the temperature in the outer periphery is likely to be lower than at the center. In response, lamp power supplied to the halogen lamps D 1 , D 2 , D 9 , and D 10  irradiating the positions corresponding to the outer periphery of the wafer  24  is increased, and hence the optical intensity is also increased. In this way, depending on the nonuniform optical characteristics of reflectivity and emissivity of the wafer  24 , the lamp heating condition can be optimally changed to prevent temperature nonuniformity and achieve a uniform temperature within the wafer  24 . Thus the yield reduction due to within-wafer nonuniformity of the semiconductor device characteristics can be prevented.  
         [0054]     As described above, in the first example, the reflectivity of the backside of the wafer  24  is measured at multiple points before the wafer  24  is transferred into the heat treatment chamber  29 . This allows heating at a temperature that is uniform within the wafer. Note that while the integral sphere  21  is used in the first example, other techniques may be used to measure reflectivity. The wafer  24  transferred to the integral sphere  21 , upon the measurement of reflectivity, is moved to another position, and the reflectivity at the new position is measured. While the measurement of reflectivity is carried out at a plurality of points on the diameter of the wafer  24  in this example, the measurement can be carried out similarly at a plurality of points arranged in a lattice or concentric pattern. After the wafer  24  is transferred into the heat treatment chamber  29 , the reflectivity data at a plurality of points within the wafer measured before transfer into the heat treatment chamber is used to calculate the target value of lamp power. That is, radiation intensity from the backside of the wafer  24  during heat treatment is combined with the reflectivity data at a plurality of points within the wafer measured before transfer into the heat treatment chamber to produce temperature data on the backside of the wafer  24 . The data is then fed back to the lamps as a distribution of electric power or profile of lamp power supplied to the lamps such as halogen lamps. Besides halogen lamps, the lamps may be xenon (Xe) flash lamps. Alternatively, lamps can be considered as a heat source. Then lasers and infrared heaters can be used as a heat source instead of lamps.  
       SECOND EXAMPLE  
       [0055]     As shown in  FIG. 15A , the second example refers to a case where a substrate peripheral structure  23  is placed around the wafer  24  during heat treatment of the wafer  24 . The semiconductor device manufacturing system and the semiconductor device manufacturing method used in the second example are the same as those in the first example. For the purpose of preventing temperature decrease on the outer periphery of the wafer  24 , a ring of silicon carbide plate is used around the wafer  24  as the substrate peripheral structure  23 . In order to control electric power supplied to halogen lamps U 1  to U 10 , D 1  to D 10  during heat treatment of the wafer  24 , temperature control is based not only on emissivity and reflectivity at a single point on the backside of the wafer  24 , but also on the emissivity and reflectivity of the substrate peripheral structure  23  as shown in  FIG. 15B . Lamp power to halogen lamps irradiating the substrate peripheral structure  23  is adjusted depending on the difference in emissivity and reflectivity between the wafer  24  and the substrate peripheral structure  23 . The figure shows a case where the emissivity is higher on the wafer  24  than on the substrate peripheral structure  23 . Thus the reflectivity is lower on the wafer  24  than on the substrate peripheral structure  23 , and hence the temperature of the substrate peripheral structure  23  is likely to be lower than that of the wafer  24 . In response, lamp power supplied to the downside lamps D 1 , D 2 , D 9 , and D 10  irradiating the substrate peripheral structure  23  is increased, and hence the optical intensity of radiation  40  irradiating the substrate peripheral structure  23  as shown in  FIG. 15A  is also increased. In this way, depending on the nonuniform optical characteristics of reflectivity and emissivity in the uniform heating temperature region  27  composed of the wafer  24  and the substrate peripheral structure  23 , the lamp heating condition can be optimally changed to achieve a uniform temperature in the uniform heating temperature region  27 , thereby preventing temperature nonuniformity and achieving a uniform temperature within the wafer  24 . Thus the yield reduction due to within-wafer nonuniformity of the semiconductor device characteristics can be prevented. Note that the upside lamps U 1  to U 10  can emit radiation  40  with an arbitrary optical intensity. For example, as shown in  FIG. 15A , the radiation  40  from the upside lamps U 1  to U 10  may have an equal optical intensity.  
       THIRD EXAMPLE  
       [0056]     As shown in  FIG. 16A , the third example also refers to a case where a substrate peripheral structure  23  is placed around the wafer  24  during heat treatment of the wafer  24 . The semiconductor device manufacturing system and the semiconductor device manufacturing method used in the third example are the same as those in the first example. For the purpose of preventing temperature decrease on the outer periphery of the wafer  24 , a ring of silicon carbide plate is used around the wafer  24  as the substrate peripheral structure  23 . In the third example, linear light sources are used for the upside halogen lamps U 1  to U 10  and the downside halogen lamps D 1  to D 10 . During heat treatment of the wafer  24 , not only electric power supplied to the downside halogen lamps D 1  to D 10  is controlled, but also electric power supplied to the upside halogen lamps U 1  to U 10 .  
         [0057]     In order to control electric power supplied to halogen lamps U 1  to U 10 , D 1  to D 10  during heat treatment of the wafer  24 , temperature control is based not only on emissivity and reflectivity at a single point on the backside of the wafer  24 , but also on the emissivity and reflectivity of the substrate peripheral structure  23  as shown in  FIG. 16C . Lamp power to halogen lamps U 1  to U 10 , D 1  to D 10  irradiating the substrate peripheral structure  23  is adjusted depending on the difference in emissivity and reflectivity between the wafer  24  and the substrate peripheral structure  23 . Because the wafer  24  and the substrate peripheral structure  23  are rotated, this rotation should be taken into consideration to select appropriate halogen lamps U 1  to U 10 , D 1  to D 10  for adjusting lamp power. As with the second example, the figure shows a case where the emissivity is higher on the wafer  24  than on the substrate peripheral structure  23 . Thus the reflectivity is lower on the wafer  24  than on the substrate peripheral structure  23 , and hence the temperature of the substrate peripheral structure  23  is likely to be lower than that of the wafer  24 . In response, as shown in  FIG. 16A , lamp power supplied to the halogen lamps U 1 , U 2 , U 9 , U 10 , D 1 , D 2 , D 9 , and D 10  irradiating the substrate peripheral structure  23  is increased, and hence the optical intensity of radiation  40  irradiating the substrate peripheral structure  23  as shown in  FIG. 16B  is also increased. In this way, depending on the nonuniform optical characteristics of reflectivity and emissivity in the uniform heating temperature region  27  composed of the wafer  24  and the substrate peripheral structure  23 , the lamp heating condition can be optimally changed to achieve a uniform temperature in the uniform heating temperature region  27 , thereby preventing temperature nonuniformity and achieving a uniform temperature within the wafer  24 . Thus the yield reduction due to within-wafer nonuniformity of the semiconductor device characteristics can be prevented.  
       FOURTH EXAMPLE  
       [0058]     As shown in  FIG. 17B , like the first example of  FIG. 14A , the fourth example also refers to a case where the wafer  24  includes a semiconductor substrate  25  and a backside film  26  provided on the backside of the semiconductor substrate  25 . The semiconductor device manufacturing system and the semiconductor device manufacturing method used in the fourth example are the same as those in the first example. The thickness of the backside film  26  is uniform at the center but decreased in the outer periphery with the distance from the center. Thus, as shown in  FIG. 17C , the emissivity in the outer periphery of the backside of the wafer  24  is lower than at the center, the reflectivity in the outer periphery of the backside of the wafer  24  is higher than at the center, and hence the temperature in the outer periphery is likely to be lower than at the center. In response, the lamp power profile  41  of the downside halogen lamps D 1  to D 10  before adjustment is changed to the lamp power profile  43  of the downside halogen lamps D 1  to D 10  after the downside adjustment so that lamp power supplied to the downside halogen lamps D 1 , D 2 , D 9 , and D 10  irradiating the positions corresponding to the outer periphery of the wafer  24  is increased. Thus the optical intensity of radiation  40  from the downside halogen lamps D 1 , D 2 , D 9 , and D 10  is increased. In this way, depending on the nonuniform optical characteristics of reflectivity and emissivity of the wafer  24 , the lamp heating condition of the downside halogen lamps D 1  to D 10  can be optimally changed to prevent temperature nonuniformity and achieve a uniform temperature within the wafer  24 . Thus the yield reduction due to within-wafer nonuniformity of the semiconductor device characteristics can be prevented.  
         [0059]     Furthermore, as shown in  FIG. 17C , while maintaining within-wafer uniformity of the backside temperature of the wafer  24 , the increased lamp power supplied to the downside halogen lamps D 1 , D 2 , D 9 , and D 10  irradiating the positions corresponding to the backside of the outer periphery of the wafer  24  is decreased within the range of the increased amount, and lamp power supplied to the upside halogen lamps U 1 , U 2 , U 9 , and U 10  irradiating the positions corresponding to the frontside of the outer periphery of the wafer  24  is increased within the range of the increased amount for the downside halogen lamps D 1 , D 2 , D 9 , and D 10 . Specifically, as shown in  FIG. 17C , the lamp power profile  43  of the downside halogen lamps D 1  to D 10  after the downside adjustment is changed to the lamp power profile  42  of the downside halogen lamps D 1  to D 10  after the dual-side adjustment. Moreover, as shown in  FIG. 17A , the lamp power profile  44  of the upside halogen lamps U 1  to U 10  before adjustment and after the downside adjustment is changed to the lamp power profile  45  of the upside halogen lamps U 1  to U 10  after the dual-side adjustment. Thus the maximum lamp power can be reduced, and hence the lamp lifetime can be extended.  
         [0060]     The first to fourth examples are only intended for specific embodiments for carrying out the invention and not to be construed as limiting the scope of the invention. The invention can be carried out in various ways without departing from the spirit or principal features thereof. That is, various modifications, improvements, and/or partial applications to other purposes can be made without departing from the scope of the claims herein, and they are all encompassed within the claims herein.