Abstract:
An X-ray exposure apparatus includes an X-ray source for generating pulsed X-rays, which are emitted radially, and first to nth exposure devices, disposed in a position facing the X-ray source and receiving the X-rays in an approximately perpendicular direction, and which use the received X-rays. The exposure devices project patterns of first to nth masks onto respective ones of first to nth substrates that are to be exposed.

Description:
FIELD OF THE INVENTION 
     This invention relates to an X-ray exposure apparatus for manufacturing devices such as microdevices by transferring a pattern from a reticle such as a mask to a substrate such as a wafer using X-rays as the exposure light. 
     BACKGROUND OF THE INVENTION 
     Semiconductor exposure apparatus of a variety of forms are in use in order to manufacture microdevices such as IC and LSI devices. Such a semiconductor exposure apparatus has an exposure light source specific to the apparatus and is so adapted that a circuit pattern written on a mask or reticle is burned into a wafer, which has been coated with a photoresist, by light emitted from the exposure light source. 
     It is required that the exposure light source have a short wavelength in order to raise the scale of integration of the microdevices. An X-ray light source has been proposed and developed as one candidate for a short-wavelength exposure light source. 
     X-ray light sources well known in the art include one using a synchrotron ring and one (referred to as a “point-source X-ray source” below) in which a target substance is irradiated with laser-light pulses to generate a plasma, and the plasma is used to produce X-rays. 
     The synchrotron ring is advantageous in that the X-rays generated exhibit a high intensity. A disadvantage of the synchrotron ring is its large size. This apparatus is inefficient in terms of cost and installation space unless the apparatus is provided with 10 to 20 ports per light source and an exposure apparatus is connected to each port. The point-source X-ray source, on the other hand, generates X-rays of comparatively low intensity, bit is small in size and generally is used by connecting one exposure apparatus per light source. 
     Various X-ray generating mechanisms have also been proposed for the point-source X-ray source. All of the point-source X-ray sources are such that radial X-rays having a certain solid angle are emitted from the X-ray source. In order for the point-source X-ray source to be used for the exposure of microdevices, it is desired that the X-rays that are projected upon the mask and wafer be parallel. To achieve this, an implementation has been considered in which the X-rays emitted from the point-source X-ray source are introduced to the exposure apparatus upon having their angle of divergence reduced using an X-ray optics element referred to as a collimator. 
     FIG. 11 is a schematic view illustrating an example of the structure of an X-ray exposure apparatus having a point-source X-ray source according to the prior art. In the X-ray exposure apparatus shown in FIG. 11, X-rays emitted from a point-source X-ray source  901  at a certain solid angle are introduced into a collimator  902 . The latter is designed in conformity with the solid angle of the X-rays introduced. X-rays output from the collimator  902  are introduced into an exposure unit  903 . The design is such that the angle of all X-rays output from the collimator  903  will be approximately perpendicular to the surface direction of a mask within the exposure unit  903 . An example of the structure of the collimator  903  is one in which a number of capillary tubes are shaped in accordance with the angle of the X-rays on the input and output sides and are bundled together. The exit of the point-source X-ray source  901 , the collimator  902  and an X-ray window  906  are constructed in the form of a chamber in which a gas can be sealed. In order to suppress attenuation of the X-rays, highly pure helium gas is sealed within the chamber as the atmosphere and the interior of the chamber is held at atmospheric pressure or lower. Though FIG. 11 is an example by which the point-source X-ray source  901  and the collimator  902  are configured in an X-ray introduction chamber  905 , several other examples of implementation are available. 
     X-rays are introduced into the exposure unit  903  from the X-ray introduction chamber  905  through the X-ray window  906 . The latter is used as an X-ray introducing portion that serves also as a pressure partition if the pressure on the side of the X-ray introduction chamber  905  differs from that within the exposure unit  903 . An example of the X-ray window  906  known in the art is a thin film obtained by forming beryllium to a thickness of several microns to several tens of microns. The exposure unit  903  is constructed to suppress attenuation of the X-rays, highly pure helium gas is sealed within the chamber of the exposure unit  903  as the atmosphere and the interior of the chamber is held at atmospheric pressure or lower. If the gas purity and pressure in the X-ray introduction chamber  905  are the same as those in the chamber of the exposure unit  903 , the X-ray window  906  can be eliminated. 
     With regard to the exposure unit  903 , a mask  904  is carried in and out by a mask transport device, which is not shown. The mask  904  is held by a mask chuck (not shown) in order that exposure may be performed. 
     A wafer  903  is carried in and out by a wafer transport device, which is not shown. The wafer  907  is held by a wafer chuck  909  mounted on a wafer stage  908  in order that exposure may be performed. The wafer stage  908  has a precision positioning mechanism for positioning an exposure area on the wafer  907  with respect to the mask  904 . 
     X-rays introduced into the exposure unit  903  have their intensity measured by an X-ray sensor  910  outside the exposure area. On the basis of the measured X-ray intensity, the exposure unit  903  controls the X-ray source device in such a manner that the optimum amount of exposure will be obtained. For example, in the case of an X-ray source device that generates X-rays in a pulsed form, the amount of exposure is controlled by commanding the number of pulses generated and the intensity of each pulse. 
     However, in a case wherein the point-source X-ray source according to the prior art is such that one collimator is combined with one point-source X-ray source, a problem which arises is that a large part of the energy radiated from the light source is not utilized. 
     In FIG. 11, only area B is utilized in exposure; other areas A and C represent dead space. In order to facilitate an understanding of the concept, FIG. 11 is drawn in such a manner that all X-rays emanate from the X-ray emission point of the point-source X-ray source. In actuality, however, emission of unnecessary X-rays is undesirable and, therefore, X-rays are shielded in the point-source X-ray source or exterior thereto. In either case, it can be construed that the efficiency with which all of the radiated energy of the light source is utilized is poor owing to the placement of various devices. 
     In order to solve the foregoing problem, the area of the collimator opening should be enlarged relative to the X-rays that emanate from the point-source X-ray source. However, if is it attempted to merely enlarge the single collimator, an angular disparity with respect to the emission angle of the collimator will grow larger as the periphery of the collimator is approached. This makes designing the apparatus extremely difficult. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention has been proposed to solve the foregoing problems of the prior art, and has as its object to provide an X-ray exposure apparatus in which the efficiency of utilization of all the radiant energy possessed by X-rays is raised over that of the prior art. The present invention adopts a creative approach wherein use is made of a plurality of collimators of a number that lend itself to actual design and one exposure unit is connected to each collimator. 
     Specifically, according to the present invention, the foregoing object is attained by providing an X-ray exposure apparatus comprising: an X-ray source for generating pulsed X-rays; first to nth exposure means which use X-rays emitted from the X-ray source, wherein the exposure means project patterns of first to nth masks onto respective ones of first to nth substrates that are to be exposed. 
     Here, “n” represents an integer of 2 or greater, but the upper limit on n is the maximum number of collimators that can be designed in view of structural limitations. 
     In a preferred embodiment, the X-ray exposure apparatus further comprises first to nth (where n represents an integer of 2 or greater) collimators for varying at least one of angle and intensity of X-rays generated by the X-ray source. 
     Thus, it is possible to provide and X-ray exposure apparatus having a plurality (n) of exposure units for manufacturing microdevices and the like, wherein efficient utilization of all the radiant energy possessed by X-rays emitted from a single point-source X-ray source is raised over that of the prior art. 
     In a preferred embodiment, the X-ray exposure apparatus further comprises first to nth shutters situated between the X-ray source and respective ones of the masks and having one, two or more shielding members for shielding X-rays that irradiate the masks, first to nth shutter drive units for driving respective ones of the shutters, and a shutter controller for controlling each of the shutters. 
     In a preferred embodiment, the shutter drive unit controls the first to nth shutters depending upon the state of the X-ray source and at least one state among the states of the first to nth exposure means. 
     In a preferred embodiment, timing of X-ray emission from the X-ray source is controlled by an X-ray emission trigger signal, the apparatus further comprising an X-ray emission trigger generating unit for generating the X-ray emission trigger signal depending upon the state of the X-ray source and at least one state among the states of the first to nth exposure means. 
     In a preferred embodiment, the intensity of X-rays from the X-ray source is controlled by an X-ray intensity control signal, the apparatus further comprising an X-ray intensity control signal generator for generating an X-ray intensity signal control signal depending upon the state of the X-ray source and at least one state among the states of the first to nth exposure means. 
     In a preferred embodiment, the X-ray exposure apparatus further comprises a total control unit, which receives information for specifying the internal status of a point-source X-ray source unit having the point-source X-ray source, as a status signal from the point-source X-ray source unit, for exercising total control, which combined the shutter control unit and a plurality of controllers that control the exposure states of each of the exposure means based upon measurement values from a plurality of sensors that measure the X-ray intensities of respective ones of the exposure means, wherein the total control unit sends the X-ray emission trigger signal generating unit a trigger generation command and sends the X-ray intensity control signal generator and an X-ray intensity value and/or X-ray intensity command. 
     In a preferred embodiment, the total control unit has means for controlling exposure timing of each exposure means in accordance with a prescribed objective, the exposure timing being tunable within a range of set values that have been set in the total control unit. 
     In a preferred embodiment, the X-ray exposure apparatus further comprises first to nth moving means for moving at least one of respective ones of the masks and the substrates. 
     In a preferred embodiment, an optical-axis center of each collimator is configured radially with respect to the X-ray source. 
     For example, laser light is condensed to irradiate a solid metal target with pulsed laser light, thereby plasmatizing the metal surface of the target to generate X-rays. 
     In any of the X-ray exposure apparatus mentioned above, the type of the X-ray source is not limited to one that generates pulsed X-rays, and X-ray sources other than those that produce pulsed X-rays can be applied to the X-ray exposure apparatus of the embodiment. 
     With regard to a change in intensity of the X-rays owing to each of the n collimators from the first to the nth collimator, the X-ray intensity distribution may be made uniform by the design of each collimator if the intensity distribution of the X-rays emitted from the X-ray source is non-uniform. 
     A method of manufacturing a semiconductor device according to the present invention comprises the steps of placing a plurality of semiconductor manufacturing apparatus, which includes the above-described X-ray exposure apparatus, in a plant for manufacturing semiconductors, and manufacturing a semiconductor device by the plurality of semiconductor manufacturing apparatus. 
     A semiconductor manufacturing plant according to the present invention comprises: a plurality of semiconductor manufacturing apparatus inclusive of the above-described X-ray exposure apparatus, a local-area network for interconnecting the plurality of semiconductor manufacturing apparatus, and a gateway for connecting the local-area network and an external network outside the plant, whereby information relating to at least one of the plurality of semiconductor manufacturing apparatus can be communicated by data communication. 
     A method of maintaining an X-ray exposure apparatus installed in a semiconductor manufacturing plant according to the present invention comprises the steps of providing a maintenance database, which is connected to an external network of the semiconductor manufacturing plant, by a vendor or user of the X-ray exposure apparatus, connecting the X-ray exposure apparatus to a local-area network within the semiconductor manufacturing plant, and maintaining the X-ray exposure apparatus, based upon information that is stored in the maintenance database, utilizing the external network and the local-area network. 
     Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and, together with the description, serve to explain the principles of the invention. 
     FIG. 1 is a schematic view illustrating an X-ray exposure apparatus according to a first embodiment of the present invention as seen from the side; 
     FIG. 2 is a schematic view illustrating the X-ray exposure apparatus according to the first embodiment of the present invention as seen from above; 
     FIG. 3 is a control block diagram of the X-ray exposure apparatus according to the first embodiment; 
     FIG. 4 is a diagram of control timing of the X-ray exposure apparatus according to the first embodiment; 
     FIG. 5 is a schematic view illustrating an X-ray exposure apparatus according to another embodiment of the present invention as seen from above; 
     FIG. 6 is a conceptual view showing a semiconductor device production system, which includes an exposure apparatus according to an embodiment of the invention, as seen from a certain angle; 
     FIG. 7 is a conceptual view showing the semiconductor device production system, which includes the exposure apparatus according to this embodiment, as seen from another angle; 
     FIG. 8 shows a specific example of a user interface in the semiconductor device production system that includes the exposure apparatus according to this embodiment; 
     FIG. 9 is a diagram useful in describing the flow of a device manufacturing process that uses the exposure apparatus according to this embodiment; 
     FIG. 10 is a diagram useful in describing a wafer process that uses the exposure apparatus according to this embodiment; and 
     FIG. 11 is a schematic view illustrating an example of the structure of an X-ray exposure apparatus having a point-source X-ray source according to the prior art. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. 
     In the embodiments set forth below, an X-ray stepper in which a mask pattern is transferred to a wafer by a step-and-repeat operation will be described. However, the present invention is not limited to the following embodiments. 
     First Embodiment 
     Reference will be had to FIGS. 1 and 2 to describe an X-ray exposure apparatus according to first embodiment of the present invention. FIG. 1 is a schematic view illustrating an X-ray exposure apparatus according to a first embodiment of the present invention as seen from the side, and FIG. 2 is a schematic view illustrating the X-ray exposure apparatus according to this embodiment as seen from above. 
     The apparatus includes a point-source X-ray source  101  that uses a solid metal target (not shown) and condenses laser light (not shown) to apply the laser light to the target in the form of pulses. The metal surface thus irradiated with the laser light is plasmatized and produces X-rays. The intensity and pulse width with respect to time of the laser light can be controlled by an intensity adjustment mechanism in the laser oscillator, not shown. By varying the intensity and pulse width with respect to time of the laser light using the intensity adjustment mechanism, the point-source X-ray source  101  is capable of controlling the intensity of the X-rays generated. 
     In this X-ray exposure apparatus, the X-rays emitted by the point-source X-ray source  101  are introduced into a first collimator  110 , second collimator  120  and third collimator  130 . The centers of these three collimators  110  to  130  are disposed so as to have the same Z coordinate in the XYZ coordinate system of the drawings. The second collimator  120  uses X-rays in an area A as its input and the third collimator  130  uses X-rays in an area C as its input. Since the three collimator  110  to  130  in this case are disposed in a radial configuration with respect to the X-ray emission point of the point-source X-ray source  101 , substantially the same design can be adopted for them. It is essential that the laser and target of the point-source X-ray source  101  be so disposed as not to interfere with an X-ray introduction chamber  102  and first, second and third exposure units  119 ,  129 ,  139 , respectively. 
     In the X-ray exposure apparatus of this embodiment, the first, second and third exposure units  119 ,  129 ,  139  are connected to the first, second and third collimators  110 ,  120 ,  130 , respectively. In the first exposure unit  119 , a first mask  113  and first wafer  114  are placed so that their angles will conform approximately to the emission angle of the first collimator  110 . The same is true with regard to the second exposure unit  129  and third exposure unit  139 . In each of the exposure units  119 ,  129 ,  139 , precise angular and positional adjustments between the optical axis of exposure and the masks  113 ,  123 ,  133  and wafers  114 ,  124 ,  134  is carried out by moving the exposure units  119 ,  129 ,  139 , per se, or the collimators  110 , 120 ,  130 . 
     In the first exposure unit  119 , the first mask  113  is brought in and sent out between a mask introduction section (not shown) and the exterior of the first exposure unit  119  by means of the mask introduction selection. The first mask  113  introduced to the first exposure unit  119  is delivered to a mask stage (not shown) by a mask transport system (not shown). The same is true with regard to the second exposure unit  129  and third exposure unit  139 . Further, in the first exposure unit  119 , the first wafer  114  is brought in and seat out between a wafer introduction section (not shown) and the exterior of the first exposure unit  119 , by means of the wafer introduction section. The first wafer  114  introduced to the first exposure unit  119  is delivered to a first wafer stage  16  by a wafer transport system (not shown). The same holds true for the second exposure unit  129  and third exposure unit  139 . 
     The first wafer stage  116 , second wafer stage  126  and third wafer stage  136  are guided along respective ones of guides by gas bearings that employ helium gas. Position information concerning the wafer stages  116 ,  126 ,  136  is measured by laser interferometers (not shown) and the stages are driven by linear motors (not shown) based upon the measurements obtained. 
     The first mask  113  is positioned with respect to a reference mark in the first exposure unit  119  by a position detector and mask stage, neither of which are shown. The first mask  113  and first wafer  114  are positioned relative to each other by the position detector and mask stage (not shown) and by the first wafer stage  116 . The second mask  123  and third mask  133  are positioned in the same manner. 
     A method of controlling the X-ray exposure apparatus according to this embodiment will now be described with reference to FIGS. 3 and 4, in which FIG. 3 is a control block diagram of the X-ray exposure apparatus according to this embodiment and FIG. 4 is a diagram of control timing of the X-ray exposure apparatus according to this embodiment. 
     The emission timing of the laser in a point-source X-ray source  301 , namely, the X-ray emission timing, is decided by an X-ray emission trigger signal. Further, the point-source X-ray source  301  is such that the intensity of the emitted laser is decided by an X-ray intensity control signal. It is preferred that the X-ray emission trigger signal and X-ray intensity control signal be signals of the kind shown in FIG.  4 . 
     Whether X-rays are capable of being emitted, and the internal device status, are constantly reported by the point-source X-ray source  301  to an exposure-apparatus total control unit  304  as a point-source X-ray source status signal. 
     A target value of an amount of exposure by the first exposure unit is set in the total control unit  304 . The set value is transmitted to a first exposure-amount controller  306 . The same is true with regard to the second and third exposure units. The total control unit  304  calculates target values of X-ray intensity and emission pulse count based upon the set value of an amount of exposure. 
     The total control unit  304  notifies an X-ray intensity control signal generator  303  of the X-ray intensity prevailing when the exposure is started, and the X-ray intensity control signal generator  303  sets the X-ray intensity control signal to a prescribed value. This control signal is set to prescribed values by the signal and timings shown in FIG.  4  and is output from the point-source X-ray source  301  to the X-ray intensity control signal generator  303 . 
     When preparations for exposure of a shot to be exposed are completed in the first exposure unit, the first exposure unit controller  306  so notifies the total control unit  304 . Alternatively, if the first exposure unit is not scheduled to perform exposure for the time being, the first exposure unit controller  306  notifies the total control unit  304  that the first exposure unit is idle. Operation is the same with regard to the second and third exposure units. When all of the first to third exposure units are ready to perform exposure or are idle, the total control unit  304  sends a shutter controller  305  a command to open the shutter (first shutter  35 , second shutter  36  or third shutter  317 ) corresponding to the exposure unit that is ready to perform exposure. In other words, a shutter corresponding to an exposure unit in the idle state is left closed. In this embodiment, the timings shown in FIG. 4 are adopted as an example of timings of the exposure states (exposure ON/exposure OFF) of the first to third exposure units and timings of the states (open/closed) of the first to third shutters. Since an exposure unit in the idle state does not undergo control of an amount of exposure, the description rendered below assumes that none of the exposure units are idle. 
     The shutter controller  305  causes first, second and third shutter drive units  312 ,  313  and  314 , respectively, to exercise control so as to open the first, second and third shutters  315 ,  316  and  317 , respectively, whereby the shutters  315 ,  316 ,  317  are driven by the shutter driver units  313 ,  313 ,  314 , respectively. Upon confirming that opening of the shutters  315 ,  316 ,  317  is completed, the first through third shutter drive units  312  to  314  so notify the shutter controller  305 . Upon being so notified, the shutter controller  305  similarly notifies the exposure-apparatus total control unit  304 . 
     The exposure-apparatus total control unit  304  receives signals giving notification of the status of the point-source X-ray source, notification of completion of shutter opening and notification that the first to third exposure units are ready to perform exposure. Upon judging that exposure is possible based upon these notification signals, the total control unit  304  starts the exposure operation. At this time, the total control unit  304  issues a trigger generation command to an X-ray emission trigger generating unit  302 . The latter outputs an X-ray emission trigger signal to the point-source X-ray source  301 . The X-ray emission trigger signal is output as the pulsed signal and at the timings shown in FIG. 4, by way of example. 
     The first exposure unit controller  306  measures the X-ray intensity by a first X-ray sensor  309 , thereby obtaining an integrated value from the start of exposure of the first shot. The exposure-apparatus total control unit  304  reads the integrated value of X-ray intensity out of the first exposure unit controller  306  for every X-ray emission pulse. The total control unit  304  notifies the X-ray intensity control signal generator  303  to lower the X-ray intensity if the integrated value of X-ray intensity of the first exposure unit has approached the target value of the amount of exposure and the difference between them has fallen below a certain threshold value. As a result, the error between the target value of the amount of exposure and the actual amount of exposure of one shot in the first exposure unit diminished. These operations are the same with regard to the second exposure unit controller  307  and second X-ray sensor  310  and with regard to the third exposure unit controller  308  and third X-ray sensor  311 . 
     If X-ray intensity is controlled across the board in the above method, there is the possibility that an error in the amount of exposure will take on a large value because the target value has already been reached or because of the other exposure units whose integrated target values of the amount of exposure are nearly the same. In order to prevent this, the total control unit  304  has adjustment means for varying the threshold value, which is used in evaluating the error, in conformity with the target value of the amount of exposure of each exposure unit. 
     With regard to the first exposure unit controller  306 , the total control unit  304  judges the error in the amount of exposure in the first exposure unit from the target value of X-ray intensity of the next pulse and performs a calculation, pulse by pulse, to determine whether the error is the minimum error. If it is determined that the exposure error is minimum, then the exposure-apparatus total control unit  304  sends the shutter controller  305  a command to close the first shutter  315 , thereby terminating exposure of one shot. These operations are the same with regard to the second exposure unit controller  307  and third exposure unit controller  308 . 
     In this embodiment, three exposure units are provided. However, the present invention is not limited to three exposure units. Two or more exposure units may be used and there is no limit upon the number of exposure units so long as this number of units can be installed. 
     Second Embodiment 
     A second embodiment of the present invention will now be described. FIG. 5 is a schematic view illustrating an X-ray exposure apparatus according to this embodiment, in which components identical with those shown in the FIGS. 1 and 2 are designated by like reference characters. 
     As shown in FIG. 5, a fourth exposure unit  149 , fourth collimator  140 , fifth exposure unit  159  and fifth collimator  150  can be provided in addition to the first to third exposure units and first to third collimators of the first embodiment. These additional exposure units and collimators are disposed along the Z-axis. This embodiment makes it possible to raise the utilization efficiency of the X-ray source even further. 
     Third Embodiment 
     A third embodiment of the present invention will now be described. In this embodiment, all or part of the wafer transport system, which is for supplying wafers to each of the exposure units and ejecting wafers whose exposure has been completed, can be shared by each of the first to third exposure units of the first embodiment and by each of the first to fifth exposure units of the second embodiment. 
     Further, all or part of the system for transporting masks or masks on which circuit patterns have been rendered for being burned into wafers can be shared by each of the first to third exposure units of the first embodiment and by each of the first to fifth exposure units of the second embodiment. 
     Fourth Embodiment 
     A fourth embodiment of the present invention will now be described. In each of the foregoing embodiments, the shots of n-number of exposure units start to be exposed simultaneously. An X-ray exposure apparatus using an exposure timing other than this will be described in this embodiment. 
     In FIG. 3, the exposure-apparatus total control unit  304  can exercise control in such a manner that the exposure timings of the n exposure units are made to conform to particular objectives. Examples of these objectives are an improvement in the utilization efficiency of the X-ray source, a reduction in exposure processing time and suppression of a decline in precision caused by vibration between exposure units. 
     In order to achieve the above, the X-ray exposure apparatus according to this embodiment sets a redundancy-allowance threshold value Tth of exposure processing time and redundancy-allowance threshold value of Pth of X-ray source pulses in the exposure apparatus total control unit  304  beforehand. In a range within which these two threshold values are not exceeded, the X-ray exposure apparatus of this embodiment is capable of tuning exposure timing in accordance with the above-objectives. 
     In this embodiment, control of the amount of exposure of each shot is carried out by controlling both the number of exposure pulses and the X-ray intensity of the X-ray source in a manner similar to that described in the first embodiment. Further, the requirements concerning exposure processing time and the requirements concerning utilization efficiency of the X-ray source are decided depending upon the aim at the time the apparatus is utilized. These requirements need only be decided based upon the particular priority. 
     Embodiment of a Semiconductor Production System 
     Described next will be an example of a system for producing semiconductor devices (e.g., semiconductor chips such as IC and LSI chips, liquid crystal panels, CCDs, thin-film magnetic heads and micromachines, etc.) utilizing the X-ray exposure apparatus described above. This system utilizes a computer network outside the semiconductor manufacturing plant to provide troubleshooting and regular maintenance of manufacturing equipment installed at the manufacturing plant and to furnish maintenance service such as the provision of software. 
     FIG. 6 illustrates the overall system as seen from a certain angle. As shown in FIG. 6, the system includes the business office  601  of the vendor (equipment supplier) that provides the equipment for manufacturing semiconductor devices. Semiconductor manufacturing apparatus for performing various processes used in a semiconductor manufacturing plant is assumed to be an actual example of the manufacturing apparatus. Examples of the apparatus are pre-treatment apparatus (e.g., lithographic apparatus such as exposure apparatus, resist treatment apparatus and etching apparatus, heat treatment apparatus, thin-film apparatus and smoothing apparatus, etc.) and post-treatment apparatus (e.g., assembly apparatus and inspection apparatus, etc.). The business office  601  includes a host management system  608  for providing a manufacturing-apparatus maintenance database, a plurality of control terminal computers  610 , and a local-area network (LAN)  609  for connecting these components into an intranet. The host management system  608  has a gateway for connecting the LAN  609  to the Internet  605 , which is a network external to the business office  601 , and a security function for limiting access from the outside. 
     Numerals  602  to  604  denote manufacturing plants of semiconductor makers (e.g., semiconductor device makers), which are the users of the manufacturing apparatus. The manufacturing plants  602  to  604  may be plants belonging to makers that differ from one another or plants belonging to the same maker (e.g., pre-treatment plants and post-treatment plants, etc.). Each of the plants  602  to  604  is provided with a plurality of manufacturing apparatus  606 , a local-area network (LAN)  611 , which connects apparatus to construct an intranet, and a host management system  607  serving as a monitoring unit for monitoring the status of operation of each manufacturing apparatus  606 . The host management system  607  provided at each of the plants  602  to  604  has a gateway for connecting the LAN  611  in each plant to the Internet  605  serving as the external network of the plants. As a result, it is possible for the LAN of each plant to access the host management system  608  on the side of the vendor  610  via the Internet  605 . By virtue of the security function of the host management system  608 , users allowed to access the host management system  608  are limited. More specifically, status information (e.g., the condition of manufacturing apparatus that has malfunctioned), which indicates the status of operation of each manufacturing apparatus  606 , can be reported from the plant side to the vendor side. In addition, information in response to such notification (e.g., information specifying how to troubleshoot the problem, troubleshooting software and data, etc.), as well as the latest software and maintenance information such as help information, can be acquired from the vendor side. A communication protocol (TCP/IP), which is used generally over the Internet, is employed for data communication between the plants  602 ˜ 604  and the vendor  601  and for data communication over the LAN  611  within each plant. Instead of utilizing the Internet as the external network of a plant, it is also possible to utilize a highly secure leased-line network (e.g., an ISDN, for example) that cannot be accessed by a third party. Further, the host management system is not limited to that provided by a vendor, for an arrangement may be adopted in which the user constructs a database, places it on an external network and allows the database to be accessed from a number of plants that belong to the user. 
     FIG. 7 is a conceptual view illustrating the overall system of this embodiment as seen from an angle different from that depicted in FIG.  6 . 
     In the earlier example, a plurality of user plants each having manufacturing apparatus are connected by an external network to the management system of the vendor that provided the manufacturing apparatus, and information concerning the production management of each plant and information concerning at least one manufacturing apparatus is communicated by data communication via the external network. In the example of FIG. 7, on the other hand, a plant having a manufacturing apparatus provided by a plurality of vendors is connected by an outside network to management systems of respective ones of the vendors of these plurality of manufacturing apparatus, and maintenance information for each manufacturing apparatus is communicated by data communication. As shown in the drawing, the system includes a manufacturing plant  701  of the user of the manufacturing apparatus, (e.g., the maker of semiconductor devices). The manufacturing line of this plant includes manufacturing apparatus for implementing a variety of processes. Examples of such apparatus are an exposure apparatus  702 , a resist treatment apparatus  703  and a thin-film treatment apparatus  704 . Though only one manufacturing plant  701  is shown in FIG. 7, in actuality, a plurality of these plants are networked in the same manner. The apparatus in the plant are interconnected by a LAN  706  to construct an intranet and the operation of the manufacturing line is managed by a host management system  705 . The business offices of vendors (e.g., equipment suppliers) such as an exposure apparatus maker  710 , a resist treatment apparatus maker  720  and a thin-film apparatus equipment maker  730  have host management systems  711 ,  721 ,  731 , respectively, for remote maintenance of the apparatus they have supplied. These have maintenance databases and gateways to the outside network, as described earlier. 
     The host management system  705  for managing each apparatus in the manufacturing plant of the user is connected to the management systems  711 ,  721 ,  731  of the vendors of these apparatus by the Internet or leased-line network serving as an external network  700 . If any of the series of equipment in the manufacturing line malfunctions, the line ceases operating. However, this can be dealt with rapidly by receiving remote maintenance from the vendor of the faulty equipment via the Internet  700 , thereby making it possible to minimize line downtime. 
     Each manufacturing apparatus installed in the semiconductor manufacturing plant has a display, a network interface and a computer for executing network-access software and equipment operating software stored in a storage device. The storage device can be an internal memory or hard disk or a network file server. The software for network access includes a special-purpose or general-purpose Web browser and presents a user interface, which has a screen of the kind shown by way of example in FIG. 8, on the display. The operator managing the manufacturing equipment at each plant enters information at the input items on the screen while observing the screen. The information includes model  801  of the manufacturing apparatus, its serial number  802 , subject matter  803  of the problem, its date of occurrence  804 , degree of urgency  805 , the particular condition  806 , countermeasure method  807  and progress report  808 . The entered information is transmitted to the maintenance database via the Internet. The resulting appropriate maintenance information is sent back from the maintenance database and is presented on the display screen. The user interface provided by the Web browser implements hyperlink functions  810 ,  811 ,  812  as illustrated and enables the operator to access more detailed information for each item, to extract the latest version of software, which is used for the manufacturing equipment, from a software library provided by the vendor, and to acquire an operating guide (help information) for reference by the plant operator. Accordingly, the maintenance information provided by the maintenance database also includes information relating to the present invention described above, and the software library also provides the latest software for implementing the present invention. 
     A process for manufacturing a semiconductor device utilizing the production system set forth above will now be described. FIG. 9 illustrates the overall flow of a process for manufacturing semiconductor devices. The circuit for the device is designed at step  1  (circuit design). A mask on which the designed circuit pattern has been formed is fabricated at step  2  (mask fabrication). Meanwhile, a wafer is manufactured using a material such as silicon or glass at step  3  (wafer manufacture). The actual circuit is formed on the wafer by lithography, using the mask and wafer that have been prepared, at step  4  (wafer process), which is also referred to as “pre-treatment”. A semiconductor chip is obtained, using the wafer fabricated at step  4 , at step  5  (assembly), which is also referred to as “post-treatment”. This step includes steps such as actual assembly (dicing and bonding) and packaging (chip encapsulation). The semiconductor device fabricated at step  5  is subjected to inspections such as an operation verification test and a durability test, at step  6  (inspection). The semiconductor device is completed through these steps and then is shipped (step  7 ). The pre- and post-treatments are performed at separate special-purpose plants. Maintenance is carried out on an a per-plant basis by the above-described remote maintenance system. Further, information for production management and equipment maintenance is communicated by data communication between the pre- and post-treatment plants via the Internet or leased-line network. 
     FIG. 10 is a flowchart illustrating the detailed flow of the wafer process mentioned above. The surface of the wafer is oxidized at step  11  (oxidation). An insulating film is formed on the wafer surface at step  12  (CVD), electrodes are formed on the wafer by vapor deposition at step  13  (electrode formation), and ions are implanted in the wafer at step  14  (ion implantation). The wafer is coated with a photoresist at step  15  (resist treatment), the wafer is exposed to the circuit pattern of the mark to print the pattern onto the wafer by the above-described exposure apparatus at step  16  (exposure), and the exposed wafer is developed at step  17  (development). Portions other than the developed photoresist are etched away at step  18  (etching), and unnecessary resist left after etching is performed is removed at step  19  (resist removal). Multiple circuit patterns are formed on the wafer by implementing these steps repeatedly. Since the manufacturing equipment used at each step is maintained by the remote maintenance system described above, malfunctions can be prevented and quick recovery is possible if a malfunction should happen to occur. As a result, the productivity of semiconductor device manufacture can be improved over the prior art. 
     Thus, in accordance with the present invention as described above, it is possible to provide an X-ray exposure apparatus in which the energy of the X-rays emitted by an X-ray source can be utilized in a highly efficient manner. Further, the number of X-ray sources (light sources) can be reduced with respect to a plurality of collimators and plurality of exposure means disposed in the X-ray exposure apparatus of the present invention. This makes it possible to lower cost and reduce installation space. In addition, labor involved in maintaining the X-ray source can be reduced in comparison with the X-ray exposure apparatus of the prior art. 
     As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the claims.