Abstract:
In a substrate processing apparatus for heating a substrate by a heater through a susceptor in a state in which the substrate is placed on the susceptor, to process the substrate, the heater is divided into a plurality of zone heaters, and a reflecting member is interposed between at least two of the plurality of zone heaters. Preferably, space exists between the susceptor and the heater. Preferably, the heater is divided into an outer peripheral zone heater and at least one inner zone heater inside the outer peripheral zone heater, the reflecting member has a recessed cross section, and the reflecting member surrounds the inner zone heater except the outer peripheral zone heater.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a substrate processing apparatus and a semiconductor device manufacturing method, and more particularly, to a substrate processing apparatus for processing a substrate such as a silicon substrate, a quartz substrate and a glass substrate, and to a semiconductor device manufacturing method in which the substrate processing apparatus can be preferably utilized.  
           [0003]    2. Description of the Related Art  
           [0004]    [0004]FIG. 4 shows one example of a substrate heating system of a conventional substrate processing apparatus. In order to enhance heat uniformity, a heater  10  is zone-divided into zone heaters  19  and  16 , a susceptor  20  is divided into divided susceptors  29  and  23 , the susceptors  29  and  23  are positioned above the zone heaters  19  and  16 , respectively, and a wafer  50  which is a substrate to be processed is disposed on the susceptor  20 . The divided susceptors  29  and  23  are heated by means of the zone heaters  19  and  16 , thereby heating the wafer  50  and keeping the heat uniformity.  
           [0005]    However, as shown in FIG. 4, due to the thickness of heater terminal fixing members  18  and the relative rotation between the susceptor  20  and the heater  10  to enhance the uniformity of a temperature across the entire surface of the wafer, this structure requires not a small gap between the susceptor  20  and the heater  10 . If this gap exists, heat radiation is generated from the divided heaters  19  and  16 . If the heaters are separated from each other, heat conduction between the divided heaters can be suppressed, but the heat radiation can not be suppressed by only separating the divided heaters from each other. Therefore, in an apparatus having a gap between the susceptor  20  and the heater  10 , there is a problem that one zone heater receives radiation heat energy from another zone heater, and the susceptor  20  also receives radiation heat energy doubly from the zone heaters in the vicinity of the divided position. The heat radiation from the zone heater in other zones largely affects the uniformity, and this is one of factors which deteriorate the controlling performance of the heater and the heat uniformity characteristic.  
           [0006]    Thus, it is a main object of the present invention to provide a substrate processing apparatus and a semiconductor device manufacturing method performing excellent temperature controllability and heat uniformity characteristics.  
         SUMMARY OF THE INVENTION  
         [0007]    According to a first aspect of the present invention, there is provided a substrate processing apparatus for heating a substrate by a heater through a susceptor in a state in which the substrate is placed on the susceptor, to process the substrate, wherein  
           [0008]    the heater is divided into a plurality of zone heaters, and a reflecting member is interposed between at least two of the plurality of zone heaters.  
           [0009]    The substrate processing apparatus is preferably applied to a case wherein space exists between the susceptor and the heater.  
           [0010]    Preferably, the heater is divided into an outer peripheral zone heater and at least one inner zone heater inside the outer peripheral zone heater, the reflecting member has a recessed cross section, and the reflecting member surrounds the inner zone heater except the outer peripheral zone heater.  
           [0011]    Preferably, the reflecting member is provided between zone heaters, of the plurality of zone heaters, which are different in temperature by 70° C. or more.  
           [0012]    Further, according to a second aspect of the present invention, there is provided a manufacturing method of a semiconductor device comprising a step of heating a substrate by a heater through a susceptor in a state in which the substrate is placed on the susceptor, to process the substrate, wherein  
           [0013]    the heater is divided into a plurality of zone heaters, and a reflecting member is interposed between at least two of the plurality of zone heaters.  
           [0014]    This method is suitably applied to a case wherein space exists between the susceptor and the heater.  
           [0015]    Preferably, the reflecting member is provided between zone heaters, of the plurality of zone heaters, which are different in temperature by 70° C or more. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    The above and further objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein:  
         [0017]    [0017]FIG. 1 is a schematic longitudinal sectional view for explaining a semiconductor wafer processing apparatus according to one embodiment of the present invention;  
         [0018]    [0018]FIG. 2 is a partially enlarged schematic longitudinal sectional view for explaining the semiconductor wafer processing apparatus according to the one embodiment of the present invention;  
         [0019]    [0019]FIG. 3 is a partially enlarged schematic longitudinal sectional view for explaining the semiconductor wafer processing apparatus according to the one embodiment of the present invention;  
         [0020]    [0020]FIG. 4 is a partially enlarged schematic longitudinal sectional view for explaining a conventional semiconductor wafer processing apparatus; and  
         [0021]    [0021]FIG. 5 is a schematic longitudinal sectional view for explaining a susceptor of the semiconductor wafer processing apparatus according to the one embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]    [0022]FIG. 1 is a schematic longitudinal sectional view for explaining a semiconductor wafer processing apparatus according to one embodiment of the present invention, FIG. 2 is a partially enlarged schematic longitudinal sectional view of the semiconductor wafer processing apparatus, and FIG. 3 is a schematic longitudinal sectional view of a heater, a susceptor, a wafer and a reflector shown in FIG. 2.  
         [0023]    A semiconductor wafer processing apparatus  1  of the present embodiment comprises a reaction chamber  40 , a susceptor  20  on which a semiconductor wafer  50  is placed and which is provided in the reaction chamber  40 , a heater  10  and reflectors  61  to  63  provided below the susceptor  20 , a gas introducing port  43 , a shower head  42  and the like. Reaction gas is supplied into the reaction chamber  40  in a manner of shower through the gas introducing port  43  and the shower head  42  and then, supplied onto the semiconductor wafer  50 , and discharged from discharging hole  44 . The wafer  50  is transferred into and out from the reaction chamber  40  through a wafer transfer port  45 .  
         [0024]    A temperature distribution across the surface of the wafer  50  is affected by a temperature of the susceptor  20 . In order to secure the heat uniformity across the entire surface of the wafer, it is important to efficiently control a temperature of the susceptor  20 . For this reason, the heater  10  is divided into three zone heaters  14 ,  15  and  16  in respective zones  1 ,  2  and  3 , and the susceptor  20  is also divided into divided susceptors  21 ,  22  and  23  at positions corresponding to the respective dividing positions of the heater into respective zones. Each of the divided susceptors  21 ,  22  and  23  is made of carbon coated with SiC. A temperature of the heater  10  is controlled by three systems, i.e., the zones  1  to  3 .  
         [0025]    The temperature controllability is enhanced by temperature-controlling the divided zone heaters independently. The positions where the heater  10  is divided into the zone heaters correspond to the positions where the susceptor  20  is divided. For example, when it is necessary to increase the temperature of only a center portion of the susceptor, it is possible to increase the temperature of only the zone heater  14  in the zone  1 .  
         [0026]    The divided susceptor  21  below the wafer  50  is lifted by a wafer transfer mechanism (not shown), and the lifted wafer  50  is transferred in and out by a wafer transfer plate  41 .  
         [0027]    In the case of the heater  16  in the outer peripheral zone  3 , since heat thereof is dissipated outward, it is necessary to increase a temperature of the heater  16  accordingly to be higher than those of the heater  15  in the zone  2  and the heater  14  in the zone  1  located inward. A difference in temperature between the heater  16  and the inner heater  15  in the zone  2  is increased and thus, a gap  17  (see FIG. 3) is provided between the heater  16  in the outer peripheral zone  3  and the heater  15  in the inner zone  2 , thereby physically separating the heaters  16  and the heaters  15  from each other. Although temperatures of the heater  15  in the zone  2  and the heater  14  in the inner zone  1  are separately controlled, since a difference between the temperatures is small, heater patterns are disposed and formed on one plate. In FIG. 3, the heater  15  in the zone  2  and the heater  14  in the zone  1  are illustrated together as one inner heater  19 . In FIG. 3, the inner divided susceptors  21  and  22  respectively corresponding to the heater  15  in the zone  2  and the heater  14  in the zone  1  are illustrated together as one inner susceptor  29 .  
         [0028]    Between the zone  2  and zone  3  of the heater  10 , that is, between the heater  15  in the zone  2  and the heater  16  in the zone  3  (in FIG. 3, between the inner heater  19  and the heaters  16  in the zone  3 ), is provided a reflector  63  made of a material having a high reflection coefficient such as Ti, Mo or the like. More preferably, the reflector  63  is made of a material also having a strong corrosion-resistance. The reflector  63  has a recessed vertical cross section.  
         [0029]    Examples of preferable material for the reflector  63  are Ti, Ni, Mo (molybdenum). Here, Ti and Ni are strong in corrosion-resistance, but are expensive. Mo is inexpensive but is prone to be corroded in ClF 3  gas which is cleaning gas. In the present embodiment, in order to prevent such gas from being mixed into the vicinity of the heater  10 , N 2  gas is introduced from a lower portion of the inside of a heater support member  35  which supports the heater  10 . Therefore, a reflector made of Mo is used .  
         [0030]    The shorter a distance  70  between the susceptor  20  and the reflector  63 , the better the condition is, and the distance  70  in this embodiment is set to be 3 mm.  
         [0031]    The zones are spatially separated by providing the reflector  63  as described above.  
         [0032]    With the above structure, since radiant heat energy is not transmitted outside the heater zones, heat interference from adjacent zone heaters does not occur, making it possible to independently control the heater zones.  
         [0033]    Further, the susceptor  20  does not receive the radiant heat energy from the zones  2  and  3  doubly and thus, the heat uniformity characteristic of the wafer  50  which is to be heated is enhanced.  
         [0034]    In this manner, the heat interference between the heater zones is prevented by the reflector  63 , the temperatures are controlled independently between the heater zones, and the controllability and the heat uniformity characteristic can be enhanced.  
         [0035]    As a condition for providing the reflector, if the reflector is provided in a region where the heater temperatures are largely different (a region where the temperature difference is 70° C. or more, especially 70° C. to 200° C.), especially great effect can be obtained. In this embodiment, the reflector  63  is therefore provided between the heaters  15  in the zone  2  and the heater  16  in the zone  3  (in FIG. 3, between the inner heater  19  and the heater  16  in the zone  3 ).  
         [0036]    Instead of providing the reflector  63  at the central portion in this manner, a reflector  64  surrounding the heater  16  in the zone  3  may be provided. However, the central dish-like reflector  63  can easily be produced inexpensively as compared with the doughnut-like reflector  64 . If it is unnecessary to reduce the cost, the reflector  64  is better to reduce the heat radiation from the outer heater  16  in the peripheral zone  3 . Both the reflectors  63  and  64  may be provided.  
         [0037]    The reflectors  61  and  62  having recessed longitudinal cross sections and surrounding all of the heater  14  in the zone  1 , the heater  15  in the zone  2  and the heater  16  in the zone  3  are provided in a double-layered manner. These reflectors are provided for preventing the heat radiation to the lower portion and in the lateral direction. The above-described materials can preferably be used for the reflectors  61  and  62 .  
         [0038]    An escape of heat is reduced and a heat insulating effect is further enhanced by covering the outer peripheral divided susceptor  23  with a susceptor cover  25  made of quartz, which contributes to output reduction of the zone heater  16 .  
         [0039]    In order to obtain better uniformity across the entire surface of the wafer, a structure in which the wafer  50  (susceptor  20 ) and the heater  10  are relatively rotated is employed. In this structure, a support member  35  of the heater  10  is used as a stationary shaft, a support member  30  of the susceptor  20  on which the wafer  50  is placed is used as a rotation shaft, and the support member  30  is coupled to a rotation introducing machine  39  using magnet coupling and the like. Taking electrical wiring to the heater  10  and the like into account, the heater  10  is fixed and the susceptor  20  is rotated.  
         [0040]    As shown in FIG. 5, an engaging member  27  is formed on a lower side (on the side of the heater  10 ) of an inner end of the outer peripheral divided susceptor  23 , and an engaging member  26  is formed on an upper side (on the side of the wafer  50 ) of an outer end of the inner divided susceptor  22 , the engaging member  26  is superposed on the engaging member  27 , and the divided susceptor  23  and the divided susceptor  22  are coupled to each other. The reason why the divided susceptors are coupled to each other with such a structure is to support the susceptor and to prevent heat from leaking in the vertical direction at the divided position. Other divided susceptors also have the same structure.  
         [0041]    According to the above mentioned embodiment of the present invention, the temperatures can be controlled independently between the heater zones, the controllability is enhanced, and the heat uniformity characteristic is enhanced.  
         [0042]    In this embodiment, the processing includes film-forming processing of a substrate to be processed and anneal processing.  
         [0043]    The entire disclosure of Japanese Patent Application No. 2000-318720 filed on Oct. 19, 2000 including specification, claims, drawings and abstract are incorporated herein by reference in its entirety.  
         [0044]    Although various exemplary embodiments have been shown and described, the invention is not limited to the embodiments shown. Therefore, the scope of the invention is intended to be limited solely by the scope of the claims that follow.