Abstract:
A semiconductor manufacturing facility has a proper strength and an anti-vibration effect. The semiconductor facility contains processing apparatuses, installation tables and an installation floor. An apparatus having a vibration source is installed on an installation table having a rigid structure. The installation table is installed on the installation floor having a floor construction including a plurality of columns, which support a floor member extending in horizontal directions. An interval of the columns is 4 m to 12 m.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to semiconductor manufacturing facilities and, more particularly, to a semiconductor manufacturing facility including an apparatus that generates vibration such as a scan-type exposure apparatus, which applies an exposure process to a semiconductor wafer, and a semiconductor manufacturing method performed by such a semiconductor manufacturing facility.  
           [0003]    2. Description of the Related Art  
           [0004]    In order to raise a manufacturing efficiency in a semiconductor manufacturing process, a diameter of a semiconductor wafer tends to increase and is presently shifting from a wafer with a diameter of 200 mm (8 inches) to a wafer with a diameter of 300 mm (12 inches). In connection with such a shift in the semiconductor wafer, semiconductor manufacturing apparatuses and semiconductor manufacturing facilities are also becoming large-scaled.  
           [0005]    For example, a scan-type exposure apparatus handling a wafer with a diameter of 300 mm in a lithography apparatus is provided with a mechanism for moving a stage on which a light-source is provided, in addition to a mechanism for moving a wafer stage on which a wafer to be processed is placed. For this reason, the scan-type exposure apparatus handling the wafer with a diameter of 300 mm has a weight as heavy as 9.5 tons. Therefore, an installation floor of a clean room on which such a heavyweight scan-type exposure apparatus is installed requires an increased withstand load. Although the scan-type exposure apparatus has a precise moving mechanism and must be made so that vibration is not transmitted thereto from outside, the apparatus itself is a source of vibration since the apparatus has a mechanism that intermittently moves the stages.  
           [0006]    The conditions of installation of the above-mentioned scan-type exposure apparatus have mainly been established according to a request from manufacturers of the apparatus. That is, it is required by the manufacturers of a scan-type exposure apparatus that the conditions of the following items should be satisfied with respect to a weight and vibration characteristic of the installation floor.  
           [0007]    (1) Acceleration of vibration in ⅓ octave-band peak-hold analysis O-P value  
           [0008]    (2) Acceleration of vibration (O-P) value in a time history waveform  
           [0009]    (3) Target accelerance of an installation floor of an exposure apparatus  
           [0010]    In order to satisfy such vibration conditions, it is general to provide an installation table or stand on an installation floor of a clean room so as to install a scan-type exposure apparatus on the installation table. As for the installation table, there is an approach of interrupting transmission of vibration by rigidity and weight of concrete. There also is an approach using an anti-vibration table, which prevents transmission of vibration by a damping mechanism incorporated in the installation table.  
           [0011]    However, a weight of a concrete installation table, which satisfies vibration conditions required by the scan-type exposure apparatus handling the wafer with a diameter of 300 mm, is as large as 11 tons, and becomes about 20 tons if when the weight of the apparatus itself is added. Therefore, the installation floor of the clean room must be so designed and constructed to withstand such a large load.  
           [0012]    Generally, the installation floor of a clean room consists of slabs supported by columns. However, in order to make the installation floor supporting a weight of about 20 tons, the number of columns must be increased very much and such a floor may not be designed by a conventional design method. Moreover, once the concrete installation table is constructed, it is difficult to move the installed position thereof. Accordingly, the concrete installation table gives less freedom of an installation position of the apparatus in the clean room. Therefore, there is a problem in that a layout of apparatuses in a clean room cannot be changed.  
           [0013]    Thus, there is a case in which an anti-vibration table is used instead of the concrete installation table. FIG. 1 is an illustrative view of a conventional installation construction of a lithography apparatus. The lithography apparatus shown in FIG. 1 has a scan-type exposure apparatus  10  and a coater/developer apparatus  12 . The scan-type exposure apparatus  10  has a very large weight, and generates vibration during operation. A laser light for exposure is supplied to the scan-type exposure apparatus  10  from a laser oscillator  14 .  
           [0014]    The scan-type exposure apparatus  10  is installed on an anti-vibration table  16  so that vibration generated by the apparatus  10  is not transmitted to other apparatuses. The anti-vibration table  16  is also referred to as an active vibration-eliminating table, and is provided with a damping device. That is, the anti-vibration table  16  does not only prevent vibration from being transmitted to the scan-type exposure apparatus  10  but also has a special mechanism to interrupt vibration generated by the apparatus itself so that the vibration is not transmitted outside. The anti-vibration table  16  is installed on an installation floor  18  of a clean room.  
           [0015]    A coater/developer apparatus  12  and a laser oscillator  14  are installed on a free access floor panel  20 , which is provided on the installation floor  18  of the clean room. Although the anti-vibration table  16  and the free access floor panel  20  are arranged on the same installation floor  18 , they are separated from each other and do not contact to each other. The installation floor  18  consists of slabs each of which is supported by a plurality of columns  22  from the bottom side. Since the scan-type exposure apparatus  10  is very heavy and is arranged on the anti-vibration table  16 , the number of columns must be increased so that the installation floor withstands such a weight and vibration is not transmitted thereto.  
           [0016]    Considering layout change of apparatuses in a clean room, it is desirable to make the installation floor  18  a uniform configuration, and, thereby, the columns  22 , which support the installation floor  18 , are arranged at a uniform interval. That is, the interval D of the column  22  supporting the installation floor  18  of the clean room is determined by an interval required for a part where the scan-type exposure apparatus  10  and the anti-vibration table  16  are arranged, and, thus, the columns  22  must be located at a very small interval over the entire clean room. Therefore, The installation floor has an excessive withstand load in parts other than the part where the scan-type exposure apparatus  10  is installed. Moreover, the anti-vibration table  16  per se becomes very heavy since the special damping device is provided, and the structure thereof also becomes complicated.  
           [0017]    Moreover, even when the above-mentioned anti-vibration table  16  is used, the summed weight of the scan-type exposure apparatus  10  and the anti-vibration table  16  is very large. Therefore, according to a conventional design approach, the interval D between the columns  22  must be decreased to about 3.5 mm. However, if the interval D of the columns  22  becomes small, a new problem may arise. Generally, devices (accessories) relevant to an apparatus installed on a part of the installation floor  18  directly above the devices are located underneath the installation floor  18 . However, if the interval D of the columns  22  is decreased, a space where the accessories are located is also decreased, and, thereby, the accessories cannot be accommodated within a predetermined range. That is, there is a problem in that the accessories to be provided under the installation floor  18  cannot be arranged well although various apparatuses can be arranged in the clean room.  
         SUMMARY OF THE INVENTION  
         [0018]    It is a general object of the present invention to provide an improved and useful semiconductor manufacturing facility in which the above-mentioned problems are eliminated.  
           [0019]    A more specific object of the present invention is to provide a semiconductor manufacturing facility having a proper strength and an anti-vibration effect as a whole facility containing processing apparatuses, installation tables and an installation floor.  
           [0020]    In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a semiconductor manufacturing facility including an apparatus having a vibration source, comprising: an installation table having a rigid structure on which the apparatus having a vibration source is installed; and a floor construction on which the installation table is installed, wherein the floor construction includes a plurality of columns which support a floor member extending in horizontal directions, and an interval of the columns is 4 m to 12 m.  
           [0021]    In the semiconductor manufacturing facility according to the present invention, the floor construction may be designed to have a predetermined accelerance. The predetermined accelerance may be a set accelerance which is obtained by dividing a necessary accelerance by a predetermined factor, the necessary accerelance being obtained by dividing a vibration allowable value A required for the apparatus by a vibration force F generated by the apparatus, where the vibration allowable value A is expressed by acceleration.  
           [0022]    Additionally, each of the columns of the floor construction may have a steel-reinforced concrete structure, and a diameter of each of the columns is 600 mm to 1400 mm. Alternatively, each of the columns of the floor construction may have a steel-frame structure, and a diameter of each of the columns is 600 mm to 1400 mm. Otherwise, each of the columns of the floor construction may be a concrete-filled steel pipe having a diameter of 600 mm to 1400 mm. Further, the installation table may have a steel-frame structure. Alternatively, the installation table has a steel-reinforced concrete structure.  
           [0023]    Additionally, there is provided according to another aspect of the present invention a semiconductor manufacturing facility including an apparatus having a vibration source, comprising: an exposure apparatus capable of handling a semiconductor wafer having a diameter equal to or greater than 300 mm; an installation table having a rigid structure on which the exposure apparatus is installed; and a floor construction on which the installation table is installed, wherein the floor construction includes a plurality of columns which support a floor member extending in horizontal directions, and an interval of the columns is 4 m to 12 m.  
           [0024]    In the semiconductor manufacturing facility according to the above-mentioned invention, the floor construction may be designed to have a predetermined accelerance. The predetermined accelerance may be a set accelerance which is obtained by dividing a necessary accelerance by a predetermined factor, the necessary accerelance being obtained by dividing a vibration allowable value A required for the apparatus by a vibration force F generated by the apparatus, where the vibration allowable value A is expressed by acceleration.  
           [0025]    The semiconductor manufacturing facility according to the present invention may further comprise: a coater installed on the floor construction so as to apply a photoconductive material onto a semiconductor wafer to be supplied to the exposure apparatus; a developer installed on the floor construction so as to apply a development process to a semiconductor wafer after being exposed by the exposure apparatus; and a light-source apparatus which supplies a light beam for exposure to the exposure apparatus.  
           [0026]    Additionally, there is provided according another aspect of the present invention a semiconductor manufacturing method using a semiconductor manufacturing facility including an apparatus having a vibration source, the semiconductor manufacturing method comprising the steps of: applying a photo-resist onto a semiconductor wafer by a coater/developer apparatus installed on a floor construction including a plurality of columns which support a floor member extending in horizontal directions, an interval of the columns being 4 m to 12 m; applying an exposure process to the semiconductor wafer by a scan-type exposure apparatus which is installed on the floor construction and capable of processing a semiconductor wafer having a diameter equal to or greater than 300 mm; and applying a development process to the semiconductor wafer, which has been exposed by the exposure apparatus, by the coater/developer apparatus.  
           [0027]    According to the present invention, the floor construction on which the semiconductor manufacturing apparatuses are installed in the semiconductor manufacturing facility can be constructed with a smaller weight and simpler structure than a floor construction according to a conventional design method. That is, the number of columns in the floor structure can be less than the number of columns according to a conventional design method, thereby simplifying the structure of floor construction. Additionally, an area of a space under the installation floor is increased, and, thereby, a sufficiently large space can be reserved for arranging auxiliary devices relating to the apparatuses installed on the installation floor. Further, the installation table can be a simple structure such as a steel-frame structure, and is movable to an arbitrary position on the installation floor.  
           [0028]    Other objects, features and advantages of the present invention will become more apparent from the following detailed descriptions when read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    [0029]FIG. 1 is an illustrative view of a conventional installation construction of a lithography apparatus;  
         [0030]    [0030]FIG. 2 is an illustrative view of a semiconductor manufacturing facility according to an embodiment of the present invention; and  
         [0031]    [0031]FIG. 3 is a flowchart of a design method of a floor construction used in the semiconductor manufacturing facility shown in FIG. 2. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]    A description will now be given, with reference to FIG. 2, of an embodiment of the present invention. FIG. 2 is an illustrative view of a semiconductor manufacturing facility according to an embodiment of the present invention. In FIG. 2, parts that are the same as the parts shown in FIG. 1 are given the same reference numerals.  
         [0033]    The semiconductor manufacturing facility shown in FIG. 2 comprises a lithography apparatus, and has a scan-type exposure apparatus  10  and a coater/developer apparatus  12 . The scan-type exposure apparatus  10  has a structure, which can handle a wafer with a diameter of 300 mm, thereby having a very large weight. A laser light for exposure is supplied to the scan-type exposure apparatus  10  from a laser oscillator  14 . It should be noted that the light beam for exposure supplied to the exposure apparatus  10  is not limited to the laser light, and, for example, an X-ray, an electron beam, etc. may be used as the light beam for exposure.  
         [0034]    Since the scan-type exposure apparatus  10  generates vibration during operation, the scan-type exposure apparatus  10  is installed on an installation table  30 , which is separated from other apparatuses, so that the vibration may not be transmitted to other apparatuses. The installation table  30  is formed as a steel-frame structure so as to be a rigid body. The installation table  30  does not only prevent vibration from being transmitted to the scan-type exposure apparatus 10 from outside but also interrupt vibration generated by the apparatus itself so that the vibration is not transmitted outside. The installation table  30  is installed on an installation floor  32  of a clean room. It should be noted that the installation table  30  is not limited to the steel-frame structure, and, for example, a steel-reinforced concrete structure may be used.  
         [0035]    The coater/developer apparatus  12  and the laser oscillator  14  are installed on a free access floor panel  20 , which is provided on the installation floor  32  of the clean room. The installation table  30  and the free access floor panel  20  are arranged on the same installation floor  32  so as to be separated from each other so that the installation table  30  and the free access floor panel  20  do not contact with each other.  
         [0036]    The installation floor  32  is made of a slab floor such as a waffle slab. The slab floor is supported by a plurality of columns  34  from the bottom side. The scan-type exposure apparatus  10  having a large weight is arranged on the installation table  30 . Therefore, if a conventional design approach is used, the number of columns  34  must be increased so as to support such a heavy weight and to make an installation floor, which can prevent transmission of vibration.  
         [0037]    However, in the semiconductor manufacturing facility according to the present invention, a damping function is achieved by the cooperation of the columns  34 , the installation floor  32  and the installation table. Thus, even if an interval between the columns  34  is large and the installation table  34  has a steel-frame structure, a semiconductor manufacturing facility, which is sufficiently usable with respect to vibration, can be constructed. That is, according to the present invention, a vibration value at the installation table  30  satisfies a ⅓ octave-band vibration allowable value, which is required for the scan-type exposure apparatus  10 . Moreover, the present invention is base on the discovery that there is no problem relating to a use environment if an accelerance of the installation floor  32  is equal to or smaller than a predetermined value.  
         [0038]    According to the present invention, the installation table  30  and the installation floor  32  are designed so as to have a set accelerance, which is obtained by dividing a necessary accelerance by a predetermined safety factor. The necessary accelerance is a value which is obtained by dividing a vibration allowable value A required for the scan-type exposure apparatus  10  by a vibration-force time history waveform F generated by the scan-type exposure apparatus  10 , where the vibration allowable value A is expressed in acceleration. The predetermined safety factor can be a value within a range of  2 - 7 .  
         [0039]    A description will be given below, with reference to a flowchart of FIG. 3, of the design approach. In step  1 , the vibration allowable value expressed in acceleration (⅓ octave-band peak hold analysis O-P value) is converted into a ⅓ octave-band peak hold analysis rms value so as to calculate a converted vibration allowable value A (unit: gal) expressed in acceleration, where the vibration allowable value is presented as an installation condition of the exposure apparatus  10  by a manufacturer thereof. Additionally, in step  2 , a frequency analysis is performed on a vibration-force time history waveform generated by the exposure apparatus  10  so as to calculate a ⅓ octave-band vibration force F (unit: N).  
         [0040]    Subsequently, in step  3 , a necessary accelerance (ACCLnec=A/F, unit: gal/N) is calculated based on the above-mentioned converted vibration allowable value A and vibration force F. The necessary accelerance is a threshold limit value which satisfies the ⅓ octave-band vibration allowable value A in the state where only the vibration influence of the scan-type exposure apparatus  10  is input to the installation table  30 . However, in an actual clean room in which the scan-type exposure apparatus  10  is installed, there exist various sources of vibration such as other manufacturing equipments and piping construction, etc. provided within the clean room. Vibrations generated by the vibration sources are input to the installation table  30  through the floor structure including the installation floor  32 . Thus, it is necessary to provide an allowance to the accelerance of the floor structure.  
         [0041]    Thus, in step  4 , a required safety factor k is set according to the number of surrounding vibration sources or a magnitude of vibration. Then, in step  5 , the necessary accelerance is divided by the safety factor k so as to calculate the set accelerance (ACCLest=ACCLnec/k, unit: gal/N). When an amount of energy is concerned, it is known that an influence given by a smaller energy matter to a larger energy matter is almost negligible if a difference between the two energy values exceeds 3 times. Therefore, the safety factor k is usually about 3, although it depends on an amount of vibration transmitted from surrounding vibration sources. If the safety factor k is smaller than 2, there are many cases in which a given vibration condition cannot be satisfied. On the other hand, if the safety factor k is greater than 7, it becomes over-design and is not preferable from a viewpoint of acquiring an installation space for other equipments or a viewpoint of economical efficiency. For this reason, it is preferable that the safety factor k is set to an optimum value within a range of 2-7 in response to surrounding vibration sources.  
         [0042]    The thus-obtained set accelerance satisfies requirements with respect to vibration influence of the scan-type exposure apparatus  10  to the installation table  30 . Moreover, the thus-obtained set accelerance satisfies the ⅓ octave-band vibration allowable value A with a certain degree of allowance also in the state where other vibrations are input from peripheral equipments. The set accelerance (ACCLest) takes various values depending on frequencies. Therefore, in step  6 , a final set accelerance is obtained as a value, which envelopes the various values of the set accelerance. It should be noted that, in the above-mentioned design approach, the floor construction including the installation table  30  and the installation floor  32  as a whole may be designed and constructed so as to satisfy the above-mentioned set accelerance. More preferably, each of the floor construction and the installation table  30  is designed and constructed so as to have the above-mentioned set accelerance individually. In such a case, it is preferable that the installation table  30  is designed and constructed so as to have a natural frequency of 70 Hz or more.  
         [0043]    A description will now be given of examples of the floor structure that is designed according to the above-mentioned design approach.  
         [0044]    In a case of the floor construction having a steel-reinforced concrete structure, the columns  34  having a thickness of 600 mm -1400 mm are arranged at an interval of 4 m -12 m. Large beams of 600 mm -1400 mm and small beams of 300 mm -1000 mm are arranged between the upper ends of the columns  34 . Then, the installation floor  32  of a slab-beam type is constructed by forming a slab floor having a thickness of 70 mm -300 mm on the large and small beams. In a case in which the slab floor is not formed as the installation floor  32 , a structure having grandchild beams of 300 mm -1000 mm arranged between the above-mentioned beams may be applicable.  
         [0045]    Additionally, in another example of the floor construction, the columns  34  having a steel structure or a concrete filled steel-pipe structure having a thickness of 400 mm -1000 mm are arranged at an interval of 4 m -12 m. Large beams of 500 mm -1400 mm having a steel-frame structure or a steel-reinforced concrete structure and small beams of 300 mm -1000 mm having a steel-frame structure or a steel-reinforced concrete structure are arranged between the upper ends of the columns  34 . A floor slab having a thickness of 70 mm -300 mm is formed on the large and small beams.  
         [0046]    Moreover, in a case in which the above-mentioned floor structure does not have a slab, the columns  34  having a steel structure or a concrete filled steel-pipe structure having a thickness of 400 mm -1000 mm are arranged at an interval of 4 m -12 m. Large beams of 500 mm-1400 mm having a steel-frame structure or a steel-reinforced concrete structure, small beams of 300 mm 1000 mm having a steel-frame structure or a steel-reinforced concrete structure and grandchild beams of 300 mm-1000 mm having a steel-frame structure or a steel-reinforced concrete structure are arranged between the upper ends of the columns  34 .  
         [0047]    In the case where a design is carried out using the above-mentioned set accelerance, sufficient measures for fine vibration can be achieved even when the installation table  30  having a steel-frame structure is installed on the installation floor  32 . Since the installation table  30  having a steel-frame structure is lighter than a table made from concrete, a load applied to the floor construction can be reduced. For this reason, an amount of steel frames used for the floor construction can be reduced. In addition, when the installation table  30  having a steel-frame structure is used, an amount of dust is greatly reduced as compared to the concrete table. Therefore, the installation table  30  is more suitable for an installation table installed in a clean room in which generation of dust must be eliminated.  
         [0048]    Moreover, even in a case where a layout of apparatuses is changed due to a change in a manufacturing process, the installation table  30  can be moved to an arbitrary position on the installation floor  32 . Therefore, a degree of freedom of arrangement of the apparatuses in a semiconductor manufacturing facility can be improved.  
         [0049]    Additionally, the horizontal rigidity of the installation table  30  can be easily adjusted by adding ribs and connection bolts. Moreover, the vertical rigidity can be almost the same as the rigidity of the floor construction by adding ribs. Thus, by designing a floor construction using the above-mentioned set accelerance, the installation table  30  of the exposure apparatus can be fabricated while attempting adjustment with a floor construction, and a practical semiconductor manufacturing facility having a lightweight as a whole can be achieved.  
         [0050]    In addition, in the above-mentioned embodiment, although the case, where the present invention is applied to the installation floor where the scan-type exposure apparatus handling a wafer with a diameter of 300 mm is installed, is explained, the present invention is not limited to the exposure apparatus. That is, the present invention is applicable to other installation floors on which a heavy apparatus having a vibration source is installed.  
         [0051]    Moreover, although, in the above-mentioned embodiment, a vibration-force time-history waveform F is used as a vibration force for calculating the necessary accelerance, the present invention is not limited to the vibration force. For example, other characteristic values representing a vibration force of the apparatus such as a vibration force spectrum may be used.  
         [0052]    The present invention is not limited to the specifically disclosed embodiments, and variations and modifications may be made without departing from the scope of the present invention.  
         [0053]    The present application is based on Japanese priority application No. 2001-086178 filed on Mar. 23, 2001, the entire contents of which are hereby incorporated by reference.