Patent Document

TECHNICAL FIELD 
       [0001]    The present disclosure relates to a peeling system which peels off a substrate to be processed and a support substrate from an overlapped substrate, a peeling method using the peeling system, and a computer storage medium. 
       BACKGROUND 
       [0002]    In recent years, for example, the diameter of semiconductor wafers (hereinafter, referred to as “wafers”) are increasing. In addition, there is a desire to make the wafers thin in a specified process such as mounting or the like. However, a large-diameter thin wafer is likely to be bent or cracked if the wafer is transferred or polished as is. Therefore, in order to reinforce the wafer, the wafer is bonded to, for example, a wafer or a glass substrate that acts as a support substrate. Thereafter, a predetermined process such as a polishing process is performed on the wafer in a state where the wafer is bonded to the support substrate as described above, and subsequently, the wafer and the support substrate are peeled off from each other. 
         [0003]    Such a peeling is performed, for example, using a peeling device. For example, the peeling device includes a first holder for holding the wafer, a second holder for holding the support substrate, and a nozzle for injecting liquid between the wafer and the support substrate. In the peeling device, the nozzle injects liquid between the wafer and the support substrate which are bonded together at an injection pressure. The injection pressure is greater than a bonding strength applied in bonding the wafer and the support substrate, preferably, at an injection pressure that is two or more times stronger than the bonding strength, thus peeling the wafer and the support substrate (see Patent Document 1). 
       PRIOR ART DOCUMENT 
     Patent Document 
       [0000]    
       
         Patent Document 1: Japanese Laid-open Patent Publication H9-167724 
       
     
         [0005]    After the wafer and the support substrate are peeled off from each other as described above, each of the bonding surfaces of the wafer and the support substrate is cleaned, and the peeling process is ended. 
         [0006]    However, in the peeling device, since the wafer and the support wafer which are not subject to the cleaning are handled, contaminants generated in the course of the peeling process adhere to the interior of the peeling device, creating particles in the peeling device. 
         [0007]    In addition, the particles generated from the peeling device may spread outside of the peeling device increasing a particle generation source. As a result, for example, the wafer may be contaminated by particles before the peeling process, which may cause defects in the course of processing the wafer. 
       SUMMARY 
       [0008]    The present disclosure has been made in consideration of the above points, and in some embodiments, particles are prevented from being generated when a peeling device peels off a substrate to be processed from a support substrate, and also particles are prevented from being spread outside of the peeling device. 
         [0009]    One embodiment is a peeling system for peeling off a substrate to be processed and a support substrate from an overlapped substrate. The overlapped substrate is formed by bonding the substrate to be processed and the support substrate by an adhesive. The peeling system includes a peeling process station configured to perform a predetermined process on the substrate to be processed, the support substrate and the overlapped substrate; a carry-in/carry-out station configured to carry at least one of the substrate to be processed, the support substrate and the overlapped substrate in and out of the peeling process station; and a transfer station configured to transfer the at least one of the substrate to be processed, the support substrate and the overlapped substrate between the peeling process station and the carry-in/carry-out station, wherein the peeling process station includes: a peeling device configured to peel off the substrate to be processed and the support substrate from the overlapped substrate; a first cleaning device configured to clean the substrate to be processed which is peeled by the peeling device; a second cleaning device configured to clean the support substrate which is peeled by the peeling device; and a transfer device configured to transfer the cleaned substrate to be processed between the peeling device and the first cleaning device, wherein a pressure within the transfer station is higher than a pressure within the peeling device, a pressure within the first cleaning device and a pressure within the second cleaning device, and wherein a pressure within the transfer device is higher than the pressure within the peeling device and the pressure within the first cleaning device. 
         [0010]    According to the peeling system of the present disclosure, the pressure within the transfer station is higher than the pressure within the peeling device, which causes a gas flow which is oriented from the transfer station to the peeling device. In addition, the pressure within the transfer unit is higher than the pressure within the peeling device, which causes a gas flow from the transfer unit to the peeling device. In other words, no atmosphere is discharged from the peeling device to the outside. Therefore, no particles are discharged from the peeling device to the outside. This makes it possible to prevent the particles generated when the substrate to be processed and the support substrate are peeled off from each other from being spread to the outside of the peeling device. 
         [0011]    The present disclosure according to another aspect is a method of peeling off a substrate to be processed and a support substrate from an overlapped substrate using a peeling system, the overlapped substrate being formed by bonding the substrate to be processed and the support substrate by an adhesive, wherein the peeling system includes: a peeling process station provided with: a peeling device configured to peel off the substrate to be processed and the support substrate from the overlapped substrate; a first cleaning device configured to clean the substrate to be processed which is peeled by the peeling device; and a second cleaning device configured to clean the support substrate which is peeled by the peeling device; a carry-in/carry-out station configured to carry at least one of the substrate to be processed, the support substrate and the overlapped substrate in and out the peeling process station; and a transfer station configured to transfer the at least one of the substrate to be processed, the support substrate and the overlapped substrate between the peeling process station and the carry-in/carry-out station, the method comprising: peeling, by the peeling device, the substrate to be processed and the support substrate from the overlapped substrate; cleaning, by the first cleaning device, the substrate to be processed which is peeled by the peeling process; and cleaning, by the second cleaning device, the support substrate which is peeled by the peeling process, wherein a pressure within the transfer station is higher than a pressure within the peeling device, a pressure within the first cleaning device and a pressure within the second cleaning device, and wherein a pressure within the transfer device is higher than the pressure within the peeling device and the pressure within the first cleaning device. 
         [0012]    The present disclosure according to still another aspect is a computer readable storage medium having a control program operating on a computer stored thereon, wherein the control program, when executed, causes the computer to perform the peeling method using the peeling system. 
       EFFECTS OF THE PRESENT DISCLOSURE 
       [0013]    According to the present disclosure, it is possible to prevent particles that are generated when a substrate to be processed and a support substrate are peeled off from each other by a peeling process from being spread to the outside of a peeling device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a plane view schematically showing the configuration of a peeling system according to an embodiment of the present disclosure. 
           [0015]      FIG. 2  is a lateral view of a wafer to be processed and a support wafer. 
           [0016]      FIG. 3  is longitudinal cross sectional view schematically showing a configuration of a peeling device. 
           [0017]      FIG. 4  is a longitudinal cross sectional view schematically showing a configuration of a first cleaning device. 
           [0018]      FIG. 5  is a transversal cross sectional view schematically showing a configuration of the first cleaning device. 
           [0019]      FIG. 6  is a longitudinal cross sectional view schematically showing a configuration of a second cleaning device. 
           [0020]      FIG. 7  is a lateral view schematically showing a configuration of a second transfer unit. 
           [0021]      FIG. 8  is a view illustrating a gas flow generated in a peeling system. 
           [0022]      FIG. 9  is a flowchart illustrating main operations of a peeling process. 
           [0023]      FIG. 10  is a view showing a state where an overlapped wafer is held by a first holding unit and a second holding unit. 
           [0024]      FIG. 11  is a view showing a state where the second holding unit is moved in vertical and horizontal directions. 
           [0025]      FIG. 12  is a view showing a state where the wafer to be processed and the support wafer are peeled off from each other. 
           [0026]      FIG. 13  is a view showing a state where the wafer to be processed is transferred from the first holding unit to a Bernoulli chuck. 
           [0027]      FIG. 14  is a view showing a state where the wafer to be processed is transferred from the Bernoulli chuck to a porous chuck. 
           [0028]      FIG. 15  is a plane view schematically showing the configuration of a peeling system according to another embodiment. 
           [0029]      FIG. 16  is a view showing a position of a cassette loading table which collects a wafer to be processed in another embodiment. 
           [0030]      FIG. 17  is a view showing a modified example of the peeling system of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Hereinafter, embodiments of the present disclosure will be described.  FIG. 1  is a plane view schematically showing a configuration of a peeling system  1  according to an embodiment. 
         [0032]    In the peeling system  1 , an overlapped wafer T as an overlapped substrate which is formed by bonding a wafer to be processed W as a substrate to be processed and a support wafer S as a support substrate by an adhesive G as shown in  FIG. 2 , is separated into the wafer to be processed W and the support wafer S. Hereinafter, in the wafer to be processed W, a surface to be bonded to the support wafer S through the adhesive G will be referred to as a “bonding surface W J ,” and a “non-bonding surface W N .” Similarly, in the support wafer S, a surface to be bonded to the wafer to be processed W through the adhesive G will be referred to as a “bonding surface S J ,” and a “non-bonding surface S N .” In addition, the wafer to be processed W is a wafer to be used as a product. A plurality of electronic circuits are formed on, e.g., the bonding surface W J  of the wafer to be processed W. Further, for example, the non-bonding surface W N  of the wafer to be processed W is subjected to a polishing so that a thickness thereof becomes thin (by, e.g., 50 μm). The support wafer S has the same diameter as that of the wafer to be processed W and supports the wafer to be processed W. While in this embodiment, the wafer has been described to be used as the support substrate, the present disclosure is not limited thereto. For example, another substrate such as a glass substrate may be used as the support substrate. 
         [0033]    As shown in  FIG. 1 , the peeling system  1  includes a carry-in/carry-out station  2  in which cassettes C W , C S  and C T  are carried in and out between the carry-in/carry-out station  2  and the outside, a peeling process station  3  including various processing units which are configured to perform a predetermined process on the wafers to be processed W, the support wafers S and the overlapped wafers T, an interface station  5  configured to deliver the wafers to be processed W between the peeling process station  3  and a post-treatment station  4  disposed adjacent thereto, and an inspection device  6  configured to inspect the wafers to be processed W before they are delivered to the post-treatment station  4 . These stations  2 ,  3 ,  4 ,  5  and  6  are connected serially. The cassettes C W , C S  and C T  are configured to accommodate a plurality of wafers to be processed W, a plurality of support wafers S, and a plurality of overlapped wafers T therein, respectively. 
         [0034]    The carry-in/carry-out station  2  and the peeling process station  3  are arranged in a line along an X-axis direction (vertical direction in  FIG. 1 ). A transfer station  7  is provided between the carry-in/carry-out station  2  and the peeling process station  3 . The interface station  5  is disposed at the backward side of the peeling process station  3  along a Y-axis direction (at the left side in  FIG. 1 ). In addition, the inspection device  6  is disposed at the forward side of the interface station  5  in the X-axis direction (the upside in  FIG. 1 ). A cleaning device  8 , which is configured to clean the wafers to be processed W after the inspection, is disposed opposite to the inspection device  6  with the interface station  5  interposed therebetween, i.e., at the backward side of the interface station  5  in the X-axis direction. 
         [0035]    A cassette loading table  10  is disposed in the carry-in/carry-out station  2 . A plurality of, e.g., three, cassette loading plates  11  are disposed in the cassette loading table  10 . The cassette loading plates  11  are arranged in a line along the Y-axis direction (the left and right direction in  FIG. 1 ). The cassette loading plates  11  can load thereon the cassettes C W , C S  and C T  when they are carried in and out between the carry-in/carry-out station  2  and the outside of the peeling system  1 , respectively. In this way, the carry-in/carry-out station  2  can hold the plurality of wafers to be processed W, the plurality of support wafers S, and the plurality of overlapped wafers T. In addition, the number of the cassette loading plates  11  is not limited to this embodiment but may be selected as appropriate. Further, the plurality of overlapped wafers T loaded in the carry-in/carry-out station  2  are inspected in advance so that they are distinguished as a normal overlapped wafer including a normal wafer to be processed W and an abnormal overlapped wafer including an abnormal wafer to be processed W. 
         [0036]    A transfer mechanism  20  is disposed in a wafer transfer region  9  which is defined inside the transfer station  7 . The transfer mechanism  20  is equipped with a transfer arm, which is movable in vertical and horizontal directions (the Y and X-axis directions), and is rotatable around the vertical axis. The transfer mechanism  20  moves inside the wafer transfer region  9  to transfer the wafer to be processed W, the support wafer S, and the overlapped wafer T between the carry-in/carry-out station  2  and the peeling process station  3 . A gas flow, oriented vertically downward and referred to as a downflow, is generated inside the transfer station  7 , i.e., in the wafer transfer region  9 . In addition, an internal atmosphere of the wafer transfer region  9  is exhausted through an exhaust port (not shown). 
         [0037]    The peeling process station  3  includes a peeling device  30  configured to peel off the wafer to be processed W and the support wafer S from the overlapped wafer T. A first cleaning device  31  configured to clean the wafer to be processed W which has been peeled off, is disposed at the backward side of the peeling device  30  along the Y-axis direction (at the left side in  FIG. 1 ). A transfer unit  32  is provided between the peeling device  30  and the first cleaning device  31 . Further, a second cleaning device  33  configured to clean the support wafer S which has been peeled off, is disposed at the forward side of the peeling device  30  in the Y-axis direction (at the right side in  FIG. 1 ). As described above, the first cleaning device  31 , the transfer unit  32 , the peeling device  30 , and the second cleaning device  33  are arranged in the peeling process station  3  in order away from the interface station  5 . 
         [0038]    The inspection device  6  inspects whether a residual of the adhesive G exists on the wafer to be processed W which is peeled by the peeling device  30 . The cleaning device  8  cleans the wafer to be processed W which has been determined to have the residual of the adhesive G thereon by the inspection device  6 . The cleaning device  8  has a bonding surface cleaning section  8   a  for cleaning the bonding surface W J  of the wafer to be processed W, a non-bonding surface cleaning section  8   b  for cleaning the non-bonding surface W N  of the wafer to be processed W, and a inverting section  8   c  for inverting the wafer to be processed W upside down. 
         [0039]    The interface station  5  is provided with a transfer mechanism  41  as another transfer mechanism, which is configured to move along a transfer path  40  extending along the Y-axis direction. The transfer mechanism  41 , which is movable in a vertical direction and is also rotatable around the vertical axis (or in a θ direction), transfers the wafer to be processed W between the peeling process station  3 , the post-treatment station  4 , the inspection device  6 , and the cleaning device  8 . A gas flow which is oriented vertically downward and is referred to as a downflow, is generated inside the interface station  5 . An internal atmosphere of the interface station  5  is exhausted through an exhaust port (not shown). 
         [0040]    Further, the post-treatment station  4  performs a predetermined post-treatment on the wafer to be processed W which is peeled by the peeling process station  3 . An example of the predetermined post-treatment may include mounting the wafer to be processed W, inspecting electric properties of the electronic circuits formed on the wafer to be processed W, dicing the wafer to be processed W on a chip-by-chip basis, or the like. Further, a gas flow oriented downward and referred to as a downflow, is generated inside the post-treatment station  4 . An internal atmosphere of the post-treatment station  4  is exhausted through an exhaust port (not shown). 
         [0041]    Next, a configuration of the aforementioned peeling device  30  will be described. As shown in  FIG. 3 , the peeling device  30  includes a housing  100  in which a plurality of equipments are accommodated. An inlet/outlet (not shown) through which the wafer to be processed W, the support wafer S, and the overlapped wafer T are passed is formed in a lateral side of the housing  100 . An opening/closing shutter (not shown) is installed at the inlet/outlet. In addition, the housing  100  of this embodiment is made of, for example, a stainless steel thin plate or the like, not an internally-airtight one. The structure of the housing  100  is not limited to this embodiment. For example, the housing  100  may be an internally-sealable vessel. 
         [0042]    An exhaust port  101  is formed at a bottom of the housing  100  so that the internal atmosphere of the housing  100  is exhausted through the exhaust port  101 . An exhaust pipe  103 , which is in communication with an exhaust device  102 , such as a vacuum pump, is connected to the exhaust port  101 . The internal atmosphere of the housing  100  is exhausted through the exhaust port  101 , which causes a gas flow, which is oriented vertically downward and is referred to as a downflow, inside the housing  100 . 
         [0043]    The housing  100  is provided with a first holding unit  110  configured to adsorb the wafer to be processed W on the bottom surface thereof, and a second holding unit  111  configured to hold the support wafer S on the upper surface thereof. The first holding unit  110  is disposed above the second holding unit  111  while being positioned to face the second holding unit  111 . That is, the peeling process is performed on the overlapped wafer T within the housing  100  with the wafer to be processed W disposed on the upper side and the support wafer S disposed on the lower side. 
         [0044]    An example of the first holding unit  110  may include a porous chuck. The first holding unit  110  includes a flat plate main body  120 . A porous body  121  is formed at a bottom side of the main body  120 . The porous body  121  has approximately the same diameter as that of the wafer to be processed W and is in contact with the non-bonding surface W N  of the wafer to be processed W. An example of the porous body  121  may include a silicon carbide. 
         [0045]    Further, a suction space  122  is formed inside the main body  120  and above the porous body  121 . The suction space  122  is formed to cover, e.g., the porous body  121 . The suction space  122 A is connected to a suction pipe  123 . The suction pipe  123  is connected to a negative pressure generator (not shown), e.g., a vacuum pump. The non-bonding surface W N  of the wafer to be processed is sucked by the suction pipe  123  through the suction space  122  and the porous body  121  so that the wafer to be processed W is adsorbed by the first holding unit  110 . 
         [0046]    In addition, a heating mechanism  124  configured to heat the wafer to be processed W is installed inside the main body  120  and above the suction space  122 . A heater, for example, may be used as the heating mechanism  124 . 
         [0047]    A support plate  130  configured to support the first holding unit  110  is installed on the upper surface of the first holding unit  110 . The support plate  130  is supported on a ceiling surface of the housing  100 . Alternatively, the support plate  130  of this embodiment may be omitted, and the first holding unit  110  may be supported by being in contact with the ceiling surface of the housing  100 . 
         [0048]    A suction pipe  140  configured to adsorb the support wafer S is installed inside the second holding unit  111 . The suction pipe  140  is connected to a negative pressure generator (not shown), e.g., a vacuum pump. 
         [0049]    Further, a heating mechanism  141  configured to heat the support wafer S is installed inside the second holding unit  111 . A heater, for example, may be used as the heating mechanism  141 . 
         [0050]    A moving mechanism  150  configured to vertically and horizontally move the second holding unit  111  and the support wafer S is provided below the second holding unit  111 . The moving mechanism  150  includes a vertical moving unit  151  configured to vertically move the second holding unit  111 , and a horizontal moving unit  152  configured to horizontally move the second holding unit  111 . 
         [0051]    The vertical moving unit  151  includes a support plate  160  for supporting the bottom surface of the second holding unit  111 , a drive unit  161  for elevating up and down the support plate  160 , and supporting members  162  for supporting the support plate  160 . The drive unit  161  is equipped with, e.g., a ball screw (not shown) and a motor (not shown) to rotate the ball screw. The supporting members  162  are vertically expansible/contractible and are disposed at, e.g., three places between the support plate  160  and a supporting body  171 , which will be described later. 
         [0052]    The horizontal moving unit  152  includes a rail  170  extending in the X-axis direction (the left and right direction in  FIG. 3 ), the supporting body  171  mounted to the rail  170 , and a drive unit  172  for moving the supporting body  171  along the rail  170 . The drive unit  172  is equipped with, e.g., a ball screw (not shown) and a motor (not shown) to rotate the ball screw. 
         [0053]    In addition, elevating pins (not shown) which elevate the overlapped wafer T or the support wafer S supported from the bottom are disposed below the second holding unit  111 . The elevating pins are inserted through through-holes (not shown) formed in the second holding unit  111  in such a manner that they project from the upper surface of the second holding unit  111 . 
         [0054]    Next, a configuration of the aforementioned first cleaning device  31  will be described. As shown in  FIG. 4 , the first cleaning device  31  includes a housing  180 . An inlet/outlet (not shown), through which the wafer to be processed W is passed, is formed in a lateral side of the housing  180 , and an opening/closing shutter (not shown) is installed in the inlet/outlet. 
         [0055]    A porous chuck  190  configured to hold and rotate the wafer to be processed W is installed in the central portion of the housing  180 . The porous chuck  190  includes a flat plate main body  191 , and a porous body  192  formed on an upper surface of the main body  191 . The porous body  192  has approximately the same diameter as that of the wafer to be processed W and is in contact with the non-bonding surface W N  of the wafer to be processed W. For example, a silicon carbide may be used as the porous body  192 . A suction pipe (not shown) is connected to the porous body  192 . The non-bonding surface W N  of the wafer to be processed W is sucked by the suction pipe through the porous body  192  so that the wafer to be processed W is adsorbed on the porous chuck  190 . 
         [0056]    A chuck drive unit  193 , which is equipped with, e.g., a motor, is provided below the porous chuck  190 . The porous chuck  190  can be rotated at a predetermined speed by the chuck drive unit  193 . Further, the chuck drive unit  193  includes an up-down drive source such as a cylinder, and can move the porous chuck  190  up and down. 
         [0057]    A cup  194  is provided around the porous chuck  190  to receive and collect liquid dropped or scattered from the wafer to be processed W. A discharge pipe  195  for draining the collected liquid and an exhaust pipe  196  for applying vacuum into the cup  194  and discharging an atmosphere therewithin are connected to the bottom surface of the cup  194 . In addition, a gas flow which is oriented vertically downward and is referred to as a downflow, is generated inside the housing  180  of the first cleaning device  31 . Further, the exhaust pipe  196  exhausts the internal atmosphere of the housing  180 . 
         [0058]    As shown in  FIG. 5 , a rail  200  extending in the Y-axis direction (the left and right direction in  FIG. 5 ) is formed at the back of the cup  194  in the X-axis direction (at the lower side in  FIG. 5 ) of the cup  194 . The rail  200  extends from the outer backside (the left side in  FIG. 5 ) to the outer front (the right side in  FIG. 5 ) of the cup  194  in the Y-axis direction, for example. An arm  201  is mounted in the rail  200 . 
         [0059]    As shown in  FIGS. 4 and 5 , a cleaning solution nozzle  203  is supported by the arm  201  to supply a cleaning solution such as an organic solvent to the wafer to be processed W. As shown in  FIG. 5 , the arm  201  is movable along the rail  200  by a nozzle drive unit  204 . With this configuration, the cleaning solution nozzle  203  can move from a standby section  205  provided at the outer front side of the cup  194  in the Y-axis direction to outer backside of the wafer to be processed W positioned within the cup  194 , and also can move along the diameter direction of the wafer to be processed W. The arm  201  is freely moved up and down by the operation of the nozzle drive unit  204  to adjust the height of the cleaning solution nozzle  203 . 
         [0060]    For example, a two-fluid nozzle is used as the cleaning solution nozzle  203 . As shown in  FIG. 4 , the cleaning solution nozzle  203  is connected to a supply pipe  210  through which the cleaning solution is supplied to the cleaning solution nozzle  203 . The supply pipe  210  is in communication with a cleaning solution supply source  211  to store the cleaning solution therein. A supply kit  212  including a valve, a flow rate regulator or the like, which controls a flow of the cleaning solution, is installed in the supply pipe  210 . The cleaning solution nozzle  203  is connected to a supply pipe  213  through which an inert gas such as a nitrogen gas is supplied to the cleaning solution nozzle  203 . The supply pipe  213  is in communication with a gas supply source  214  to store the inert gas therein. A supply kit  215  including a valve, a flow rate regulator or the like, which controls a flow of the inert gas, is installed in the supply pipe  213 . The cleaning solution and the inert gas are mixed inside the cleaning solution nozzle  203  so that the mixture is supplied to the wafer to be processed W. Hereinafter, in some cases, the mixture of the cleaning solution and the inert gas is simply referred to as a “cleaning solution.” 
         [0061]    Elevating pins (not shown) which elevate the wafer to be processed W supported from the bottom may be installed below the porous chuck  190 . In such a case, the elevating pins are inserted through through-holes (not shown) formed in the porous chuck  190  in such a manner that they project from the upper surface of the porous chuck  190 . Further, the wafer to be processed W may be separated from the porous chuck  190  by elevating the elevating pins upward instead of elevating the porous chuck  190 . Since configurations of the bonding surface cleaning section  8   a  and the non-bonding surface cleaning section  8   b  of the aforementioned cleaning device  8  are similar to that of the first cleaning device  31 , including generating a gas flow which is oriented vertically downward and is referred to as a downflow, and therefore a description thereof will be omitted to avoid duplication. 
         [0062]    The second cleaning device  33  has approximately the same configuration as that of the aforementioned first cleaning device  31 . As shown in  FIG. 6 , in the second cleaning device  33 , a spin chuck  220  is installed instead of the porous chuck  190  of the first cleaning device  31 . The spin chuck  220  has a horizontal upper surface on which suction holes (not shown) for sucking, e.g., the support wafer S, is formed. By the suctioning force of the suction holes, the support wafer S can be adsorbed on the spin chuck  220 . The other configurations of the second cleaning device  33  are similar to those of the first cleaning device  31 , including generating a gas flow which is oriented vertically downward and is referred to as a downflow, and therefore a description thereof will be omitted to avoid duplication. 
         [0063]    In the second cleaning device  33 , a back rinse nozzle (not shown) which injects the cleaning solution toward the rear surface of the wafer to be processed W, i.e., the non-bonding surface W N , may be installed below the spin chuck  220 . The cleaning solution injected from the back rinse nozzle cleans the non-bonding surface W N  of the wafer to be processed W and the peripheral portion thereof. 
         [0064]    Next, a configuration of the aforementioned transfer unit  32  will be described. As shown in  FIG. 1 , the transfer unit  32  includes a transfer mechanism  231  which is installed in a wafer transfer region  230  that is bounded by the first cleaning device  31 , the peeling device  30  and the wafer transfer region  9 . As shown in  FIG. 7 , the transfer mechanism  231  includes a Bernoulli chuck  232  configured to hold the wafer to be processed W. The Bernoulli chuck  232  blasts air to float the wafer to be processed W so that the wafer to be processed W can be held in a contactless state. The Bernoulli chuck  232  is supported by a supporting arm  233 . The supporting arm  233  is supported by a first drive unit  234 . By the operation of the first drive unit  234 , the supporting arm  233  is rotatable around a horizontal axis and also horizontally expansible/contractible. A second drive unit  235  is provided below the first drive unit  234 . By the operation of the second drive unit  235 , the first drive unit  234  is rotatable around a vertical axis and also vertically movable. Further, a gas flow which is oriented vertically downward and is referred to as a downflow, is generated inside the transfer unit  32 , i.e., in the wafer transfer region  230 . An internal atmosphere of the wafer transfer region  230  is exhausted through the exhaust port (not shown). 
         [0065]    A configuration of the transfer mechanism  41  in  FIG. 1  is similar to that of the aforementioned transfer mechanism  231  of the transfer unit  32  except that the second drive unit  235  of the transfer mechanism  41  is mounted on the transfer path  40  and the transfer mechanism  41  is configured to be movable along the transfer path  40 . Therefore a description thereof will be omitted to avoid duplication. 
         [0066]    As shown in  FIG. 1 , the aforementioned peeling system  1  includes a control unit  300 . The control unit  300  is, for example, a computer, and includes a program storage (not shown). The program storage stores a program which controls processing of the wafer to be processed W, the support wafer S, and the overlapped wafer T in the peeling system  1 . The program storage also stores a program which controls operation of a driving system including the aforementioned processing devices and the transfer unit to implement a peeling process in the peeling system  1 , which will be described later. The programs may be installed in the control unit  300   a  from a computer readable storage medium H such as a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magneto-optical disk (MO), a memory card or the like. 
         [0067]    Next, when a peeling process for the overlapped wafer T is performed in the peeling system  1  configured as above, a gas flow generated within the peeling system  1  will be described with reference to  FIG. 8 . In  FIG. 8 , each arrow indicates a direction of the gas flow. 
         [0068]    Out of the post-treatment station  4 , the interface station  5 , and the peeling process station  3  in the peeling system  1 , a pressure within the post-treatment station is highest and a pressure within the peeling process station  3  is lowest. Thus, the pressure within the post-treatment station is higher than the pressure within the interface station  5 , which causes a gas flow from the post-treatment station  4  to the interface station  5 . In addition, the pressure within the interface station  5  is higher than the pressure within the peeling process station  3 , which causes a gas flow from the interface station  5  to the peeling process station  3 . 
         [0069]    Meanwhile, the pressure within the interface station  5  is lower than a pressure within the inspection device  6  but is higher than those within the bonding surface cleaning section  8   a , the non-bonding surface cleaning section  8   b  and the inverting section  8   c  of the cleaning device  8 . This causes a gas flow from the inspection device  6  to the interface station  5  and a gas flow from the interface station  5  to the bonding surface cleaning section  8   a , the non-bonding surface cleaning section  8   b , and the inverting section  8   c  of the cleaning device  8 , respectively. 
         [0070]    In addition, a pressure within the transfer station  7  is higher than a pressure within the peeling device  30 , a pressure within the first cleaning device  31 , and a pressure within the second cleaning device  33  of the peeling process station  3 . This causes gas flows from the transfer station  7  to the peeling device  30 , the first cleaning device  31 , and the second cleaning device  33 , respectively. 
         [0071]    In addition, a pressure within the transfer unit  32  is higher than the pressure within the peeling device  30  and the pressure within the second cleaning device. This causes gas flows from the transfer unit  32  to the peeling device  30  and the second cleaning device  31 , respectively. 
         [0072]    Next, a peeling process of the wafer to be processed W and the support wafer S, to be performed using the peeling system  1  configured as above, will be described.  FIG. 9  is a flowchart illustrating main operations of the peeling process. 
         [0073]    First, a cassette C T  with a plurality of overlapped wafers T accommodated therein, an empty cassette C W , and an empty cassette C S  are loaded on a respective cassette loading plate  11  of the carry-in/carry-out station  2 . Thereafter, each of the overlapped wafers T within the cassette C T  is taken out by the transfer mechanism  20  and then is transferred to the peeling device  30  of the peeling process station  3 . At this time, the overlapped wafer T is transferred while the wafer to be processed W is positioned at the upper side and the support wafer S is positioned at the lower side. 
         [0074]    The overlapped wafer T loaded into the peeling device  30  is adsorbed to the second holding unit  111 . Thereafter, the second holding unit  111  is elevated by the moving mechanism  150  so that, as shown in  FIG. 10 , the overlapped wafer T is held by the first holding unit  110  and the second holding unit  111  with the overlapped wafer T interposed therebetween. At this time, the non-bonding surface W N  of the wafer to be processed W is adsorbed to the first holding unit  110 , and the non-bonding surface S N  of the support wafer S is adsorbed to the second holding unit  111 . 
         [0075]    Thereafter, the overlapped wafer T is heated to a predetermined temperature, e.g., 200 degrees C., by the heating mechanisms  124  and  141 . Thus, the adhesive G in the overlapped wafer T is softened. 
         [0076]    Subsequently, while the heating mechanisms  124  and  141  heat the overlapped wafer T to maintain the soft state of the adhesive G, the moving mechanism  150  moves the second holding unit  111  and the support wafer S in vertical and horizontal directions, i.e., obliquely downward, as shown in  FIG. 11 . Then, as shown in  FIG. 12 , the wafer to be processed W held by the first holding unit  110  and the support wafer S held by the second holding unit  111  are peeled off from each other (Operation A 1  in  FIG. 9 ). 
         [0077]    At this time, the second holding unit  111  is moved by a distance of 100 μm in the vertical direction and by a distance of 300 mm in the horizontal direction. In this embodiment, a thickness of the adhesive G in the overlapped wafer T is in the range of, e.g., 30 μm to 40 μm, and a height of an electronic circuit (bump) formed on the bonding surface W J  of the wafer to be processed W is, e.g., 20 μm. Accordingly, a distance between the electronic circuit formed on the wafer to be processed W and the support wafer S becomes very small. As such, for example, when the second holding unit  111  is moved only in the horizontal direction, the electronic circuit is brought into contact with the support wafer S, which may cause damages to the electronic circuit. In this embodiment the electronic circuit is not brought into contact with the support wafer S because the second holding unit  111  is moved simultaneously in both the horizontal and vertical directions, thus preventing the electronic circuit from being damaged. A ratio of a vertical movement distance to a horizontal movement distance of the second holding unit  111  may be set based on the height of the electronic circuit (bump) formed on the wafer to be processed W. 
         [0078]    Thereafter, the wafer to be processed W peeled by the peeling device  30  is transferred to the first cleaning device  31  by the transfer mechanism  231 . Hereinafter, the transfer of the wafer to be processed W by the transfer mechanism  231  will be described. 
         [0079]    As shown in  FIG. 13 , the supporting arm  233  is extended such that the Bernoulli chuck  232  is positioned below the wafer to be processed W which is held by the first holding unit  110 . Thereafter, the Bernoulli chuck  232  is lifted up to release the suction of the wafer to be processed W by the suction pipe  123  in the first holding unit  110 . Then, the wafer to be processed W is transferred from the first holding unit  110  to the Bernoulli chuck  232 . At this time, although the bonding surface W J  of the wafer to be processed W is held by the Bernoulli chuck  232 , since the Bernoulli chuck  232  holds the wafer to be processed W in a contactless manner, the electronic circuit formed on the bonding surface W J  of the wafer to be processed W are not damaged. 
         [0080]    Next, as shown in  FIG. 14 , the supporting arm  233  rotates such that the Bernoulli chuck  232  is lifted above the porous chuck  190  of the first cleaning device  31 . Simultaneously, the Bernoulli chuck  232  is inverted such that the wafer to be processed W is oriented downward. At this time, the porous chuck  190  is elevated above the cup  194  and is on standby. Thereafter, the wafer to be processed W is transferred from the Bernoulli chuck  232  to the porous chuck  190  and then is adsorbed to the porous chuck  190 . 
         [0081]    As described above, when the wafer to be processed W is adsorbed to the porous chuck  190 , the porous chuck  190  is lowered to a predetermined position. Subsequently, the cleaning solution nozzle  203  positioned within the standby section  205  is moved, by the arm  201 , above the central portion of the wafer to be processed W. Thereafter, the cleaning solution is supplied from the cleaning solution nozzle  203  onto the bonding surface W J  of the wafer to be processed W while rotating the wafer to be processed W by the porous chuck  190 . The supplied cleaning solution is spread to the entire surface of the bonding surface W J  of the wafer to be processed W due to a centrifugal force of the rotation, and the bonding surface W J  of the wafer to be processed W is cleaned (Operation A 2  in  FIG. 9 ). 
         [0082]    As described above, the plurality of the overlapped wafers T loaded into the carry-in/carry-out station  2  are inspected in advance to distinguish between a normal overlapped wafer T including a normal wafer to be processed W and an abnormal overlapped wafer T including an abnormal wafer to be processed W. 
         [0083]    The bonding surface W J  of the normal wafer to be processed W peeled off from the normal overlapped wafer T is cleaned in Operation A 2  and then transferred to the inspection device  6  by the transfer mechanism  41 . The transfer of the wafer to be processed W by the transfer mechanism  41  is substantially similar to that of the wafer to be processed W by the aforementioned transfer mechanism  231 . Thus a description thereof will be omitted to avoid duplication. 
         [0084]    The inspection device  6  inspects whether the residual of the adhesive G exists on the bonding surface W J  of the wafer to be processed W (Operation A 3  in  FIG. 9 ). If the inspection device  6  determines that the residual of the adhesive G exists, the transfer mechanism  41  transfers the wafer to be processed W to the bonding surface cleaning section  8   a  of the cleaning device  8  where the bonding surface W J  is cleaned (Operation A 4  in  FIG. 9 ). After the bonding surface W J  is cleaned, the transfer mechanism  41  transfers the wafer to be processed W to the inverting section  8   c  where the wafer to be processed W is inverted upside down. Meanwhile, if no residual of the adhesive G is determined to exist, the inverting section  8   c  inverts the wafer to be processed W without being transferred to the bonding surface cleaning section  8   a  (Operation A 5  in  FIG. 9 ). 
         [0085]    Thereafter, the transfer mechanism  41  transfers the inverted wafer to be processed W to the inspection device  6  where the inspection is performed on the non-bonding surface W N  (Operation A 6  in  FIG. 9 ). If the residual of the adhesive G is determined to exist in the non-bonding surface W N , the wafer to be processed W is transferred to the non-bonding surface cleaning section  8   c  by the transfer mechanism  41  where the non-bonding surface W N  is cleaned (Operation A 7  in  FIG. 9 ). Subsequently, the cleaned wafer to be processed W is transferred to the post-treatment station  4  by the transfer mechanism  41 . Meanwhile, if no residual of the adhesive G is determined to exist by the inspection device  6 , the wafer to be processed W is transferred to the post-treatment station  4  as it is without being transferred to the non-bonding surface cleaning section  8   b.    
         [0086]    Thereafter, the wafer to be processed W is subjected to a predetermined post-treatment in the post-treatment station  4  (Operation A 8  in  FIG. 9 ). In this manner, the wafer to be processed W is used as a product. 
         [0087]    On the other hand, the bonding surface W J  of the abnormal wafer to be processed W peeled off from the abnormal (or defective) overlapped wafer T is cleaned in Operation A 2  and then transferred to the carry-in/carry-out station  2  by the transfer mechanism  20 . Thereafter, the abnormal wafer to be processed W is discharged from the carry-in/carry-out station  2  to the outside for the collection (Operation A 9  in  FIG. 9 ). 
         [0088]    While the aforementioned operations A 1  to A 9  are performed on the wafer to be processed W, the support wafer S peeled off from the peeling device  30  is transferred to the second cleaning device  33  by the transfer mechanism  20 . In the second cleaning device  33 , the bonding surface S J  of the support wafer S is cleaned (Operation A 10  in  FIG. 9 ). The cleaning of the support wafer S in the second cleaning device  33  is similar to that of the wafer to be processed W in the aforementioned first cleaning device  31  and, therefore a description thereof will be omitted to avoid duplication. 
         [0089]    Thereafter, the support wafer S having the cleaned bonding surface S J  is transferred to the carry-in/carry-out station  2  by the transfer mechanism  20 . The support wafer S is then discharged from the carry-in/carry-out station  2  to the outside for the collection (Operation All in  FIG. 9 ). In this manner, a series of the peeling processes for the wafer to be processed W and the support wafer S is terminated. 
         [0090]    According to the above embodiments, the pressure within the transfer station  7  is higher than the pressure within the peeling device  30 , which causes the gas flow from the transfer station  7  to the peeling device  30 . In other words, the internal atmosphere of the peeling device  30  is not discharged to the transfer station  7  side. In addition, the pressure within the transfer unit  32  is higher than the pressure within the peeling device  30 , which causes the gas flow from the transfer unit  32  to the peeling device  30 . As such, the internal atmosphere of the peeling device  30  is not discharged to the transfer unit  32  side. Thus, no particle is discharged from the peeling device  30  to the outside. This prevents the particles, which are generated when the wafer to be processed W and the support wafer S are peeled off, from being spread to the outside the peeling device  30 . 
         [0091]    In addition, the pressure within the interface station  5  is higher than the pressure within the peeling process station  3  and is lower than the pressure within the post-treatment station  4 , which causes the gas flow which is oriented from the post-treatment station  4  to the peeling process station  3 . Thus, even when the particles are spread into the peeling process station  3 , it is possible to prevent the particles from flowing into the interface station  5  and the post-treatment station  4  from the peeling process station  3 . This allows the interior of the post-treatment station  4  configured to perform the post-treatment to be maintained at a clean state, Thus, it is possible to prevent deterioration in a production yield which may be caused by the particles being attached onto the wafer to be processed W in the post-treatment station  4 . 
         [0092]    In addition, the pressure within the transfer station  7  is higher than the pressure within the first cleaning device  31  and the pressure within the second cleaning device  33 , which causes the gas flows from the transfer station  7  to the first cleaning device  31  and the second cleaning device  33 , respectively. This prevents the particles generated with the cleaning operations of the respective cleaning devices  31  and  33  from flowing into the transfer station  7 . Accordingly, it is possible to prevent the particles from being attached onto the overlapped wafer T, the wafer to be processed W, and the support wafer S during the transfer. 
         [0093]    Further, the pressure within the inspection device  6  is higher than the pressure within the interface station  5 , which causes the gas flow from the inspection device  6  to the interface station  5 . As such, even when particles are spread to the interface station  5 , it is possible to prevent the particles from flowing into the inspection device  6 . This allows the interior of the inspection device  6  to be maintained at a clean state, which makes it possible to prevent, e.g., the normal wafer to be processed W from being contaminated by the particles in the inspection device  6 . 
         [0094]    Further, the pressure within the interface station  5  is higher than the pressure within the cleaning device  8 , which causes the gas flows from the interface station  5  to the cleaning device  8 . This prevents the particles from being attached onto the wafer to be processed W in the course of transferring the wafer to be processed W in the interface station  5 . 
         [0095]    Further, the internal atmospheres of the first cleaning device  31 , the second cleaning device  33 , the peeling device  30 , and the cleaning device  8  are exhausted to the outside so that an internal atmosphere of the peeling system  1  is exhausted to the outside. This prevents the particles from existing in the internal atmosphere of the peeling system  1 . 
         [0096]    According to the above embodiments, after the wafer to be processed W and the support wafer S are peeled off from the overlapped wafer T in the peeling device  30 , the peeled-off wafer to be processed W can be cleaned by the first cleaning device  31  and the peeled-off support wafer S can be cleaned by the second cleaning device  33 . As described above, according to the above embodiments, a series of processes including peeling the wafer to be processed W and the support wafer S and cleaning the wafer to be processed W and the support wafer S can be effectively performed in the single peeling system  1 . In addition, the cleaning of the wafer to be processed W and the cleaning of the support wafer S are simultaneously performed in the first cleaning device  31  and the second cleaning device  33 , respectively. Furthermore, while the wafer to be processed W and the support wafer S are peeled off from each other in the peeling device  30 , another wafer to be processed W and another support wafer S may also be processed in the first cleaning device  31  and the second cleaning device  33 , respectively. Therefore, it is possible to efficiently perform the peeling of the wafer to be processed W and the support wafer S, which improves a throughput of the peeling process. 
         [0097]    In addition, when the wafer to be processed W peeled by the peeling process station  3  is the normal wafer to be processed W, it is subjected to the predetermined post-treatment in the post-treatment station  5  to use the same as a product. On the other hand, when the wafer to be processed W peeled by the peeling process station  3  is the abnormal wafer to be processed W, it is collected by the carry-in/carry-out station  2 . Accordingly, since only the normal wafer to be processed W is used as the product, it is possible to improve the production yield. Further, the abnormal wafer to be processed W is collected. The collected wafer to be processed W may be reused depending on an abnormal degree leading to an effective use of resources and reduction in manufacturing costs. 
         [0098]    The series of processes as described above, including the peeling of the wafer to be processed W and the support wafer S and the post-treatment of the wafer to be processed W, are performed thus further improving the production yield of process for the wafer. 
         [0099]    In addition, the support wafer S peeled by the peeling device  30  is cleaned and then is collected by the carry-in/carry-out station  2  so that the support wafer S can be reused. This makes an effective use of resources and reduces manufacturing costs. 
         [0100]    Furthermore, the peeling device  30  moves the second holding unit  111  and the support wafer S in the vertical and horizontal directions using the moving mechanism  150  while heating the overlapped wafer T such that the wafer to be processed W and the support wafer S are peeled off from each other. The movement of the second holding unit  111  in both the vertical and horizontal directions prevents the electronic circuit formed on the wafer to be processed W from being brought into contact with the support wafer S even when a distance therebetween is very small. Thus, it is possible to avoid the contact between the wafer to be processed W and the support wafer S. This prevents the electronic circuit from being damaged and facilitates the peeling process of the wafer to be processed W and the support wafer S. 
         [0101]    In addition, since each of the transfer mechanism  231  and the transfer mechanism  41  is equipped with the Bernoulli chuck  232  configured to hold the wafer to be processed W, it is possible to stably hold the wafer to be processed W even for a thin one. Further, in the transfer mechanism  231 , since the Bernoulli chuck  232  holds the bonding surface W J  of the wafer to be processed W in a contactless manner, it is possible to prevent the electronic circuit formed on the bonding surface W J  of the wafer to be processed W from being damaged. 
         [0102]    Since the first cleaning device  31  includes the porous chuck  190  configured to hold the wafer to be processed W, it is possible to stably hold the wafer to be processed W even for a thin one. 
         [0103]    In the above embodiments, since the inspection device  6  is configured to inspect the wafer to be processed W, it is possible to correct process conditions to be applied in the peeling system  1  based on results of the inspection. This makes it possible to further stably peel off the wafer to be processed W and the support wafer S. 
         [0104]    While in the above embodiments, the second holding unit  111  has been described as being moved in the vertical and horizontal directions in the peeling device  30 , the first holding unit  110 , instead of the second holding unit  111 , may be moved in the vertical and horizontal directions. Alternatively, both the first holding unit  110  and the second holding unit  111  may be moved in the vertical and horizontal directions. 
         [0105]    While the second holding unit  111  has been described as being moved in the both vertical and horizontal directions in the peeling device  30 , the second holding unit  111  may be moved only in the horizontal direction and a moving speed thereof may be varied. As an example, an initial moving speed of the second holding unit  111  may be set to a lower level and be gradually increased. That is, when the second holding unit  111  starts to move, since a bonding area between the wafer to be processed W and the support wafer S is large so that the electronic circuit formed on the wafer to be processed W can be easily influenced by the adhesive G, the initial moving speed of the second holding unit  111  is set to a lower level. As the bonding area between the wafer to be processed W and the support wafer S becomes small, the influence of the adhesive G on the electronic circuit formed on the wafer to be processed W becomes smaller, the moving speed of the second holding unit  111  is gradually increased. This avoids the contact between the electronic circuit and the support wafer S and prevents the electronic circuit from being damaged. 
         [0106]    While in the above embodiments, the second holding unit  111  has been described to be moved in the vertical and horizontal directions in the peeling device  30 , when a distance between the electronic circuit formed on the wafer to be processed W and the support wafer S is sufficiently large, the second holding unit  111  may be moved only in the horizontal direction. This configuration prevents the electronic circuit from being brought into contact with the support wafer S and also simplifies controlling the movement of the second holding unit  111 . In some embodiments, the second holding unit  111  may be moved only in the vertical direction to peel off the wafer to be processed W and the support wafer S from each other. Alternatively, an end of a peripheral portion of the second holding unit  111  may be moved only in the vertical direction to peel off the wafer to be processed W and the support wafer S from each other. 
         [0107]    While in the above embodiments, the wafer to be processed W and the support wafer S have been described to be peeled off while positioning the wafer to be processed W at the upper side and the support wafer S at the lower side, the positions of the wafer to be processed W and the support wafer S may be inverted. 
         [0108]    In the transfer mechanism  231  according to the above embodiments, a plurality of supply holes (not shown) through which the cleaning solution is supplied may be formed on a surface of the Bernoulli chuck  232 . With this configuration, when the wafer to be processed W is transferred from the Bernoulli chuck  232  to the porous chuck  190  of the first cleaning device  31 , the cleaning solution is supplied from the Bernoulli chuck  232  onto the bonding surface W J  of the wafer to be processed W, thus cleaning the bonding surface W J  and also the Bernoulli chuck  232  itself This reduces the amount of time required to clean the wafer to be processed W in the first cleaning device  31  later, which improves a production yield in the peeling process. Furthermore, since the Bernoulli chuck  232  can be cleaned, it is possible to transfer a subsequent wafer to be processed W in a reliable manner. 
         [0109]    While in the above embodiments, the transfer mechanism  41  has been described to include the Bernoulli chuck  232 , it may include a porous chuck (not shown) instead of the Bernoulli chuck  232 . Even in such a case, it is possible to stably absorb a thin wafer to be processed W using the porous chuck. 
         [0110]    In the above embodiments, the two-fluid nozzle has been described to be used as the cleaning solution nozzle  203  of the first cleaning device  31  and the second cleaning device  33 , but is not limited thereto, various types of nozzles may be used. As an example, a nozzle body in which a nozzle configured to supply a cleaning solution and a nozzle configured to supply an inert gas are combined, a spray nozzle, a jet nozzle, a megasonic nozzle, or the like may be used as the cleaning solution nozzle  203 . In addition, in order to improve a production yield in the cleaning process, a cleaning solution heated to, e.g., 80 degrees C., may be supplied. 
         [0111]    In some embodiments, in addition to the cleaning solution nozzle  203 , a nozzle configured to supply IPA (isopropyl alcohol) may be provided in the first cleaning device  31  and the second cleaning device  33 . In such a case, after the wafer to be processed W or the support wafer S is cleaned by the cleaning solution supplied from the cleaning solution nozzle  203 , the cleaning solution supplied onto the wafer to be processed W or the support wafer S is substituted with the IPA. This makes it possible to more reliably clean the bonding surface W J  or S J  of the wafer to be processed W or the support wafer S. 
         [0112]    The peeling system  1  according to the above embodiments may include a temperature adjusting unit (not shown) which cools the wafer to be processed W heated in the peeling device  30  up to a predetermined temperature. This makes it possible to adjust the temperature of the wafer to be processed W to a suitable temperature, thus smoothly performing a subsequent process. 
         [0113]    While in the above embodiments, the wafer to be processed W has been described to be subjected to the post-treatment in the post-treatment station  4  for the product, the present disclosure is not limited thereto. For example, the present disclosure may be applied when a wafer to be processed used in, e.g., three-dimensional integration technique, is peeled off from a support wafer. The three-dimensional integration technique is a technique to meet a recent demand for high density integration of semiconductor devices, in which a plurality of highly-integrated semiconductor devices are stacked in three dimensions, instead of placing the plurality of semiconductor devices on a horizontal plane. Even in this three-dimensional integration technique, there is a desire to stack thin the wafer to be processed. The thin wafer to be processed is bonded to a support wafer, and subsequently, a predetermined process is performed onto the bonded wafers. 
         [0114]    While in the above embodiments, the peeling process has been described to be performed onto the wafer to be processed W that is thinned by the polishing process, the present disclosure may be applied in peeling off the overlapped wafer T before the wafer to be processed W is thinned by the polishing process. The peeling process of the overlapped wafer T before the wafer to be processed W is thinned, may be performed when the overlapped wafer T is determined to have a defect before the thinning process is performed, for example. As an example, as shown in  FIG. 15 , the peeling process may be performed by a peeling system  320  including the carry-in/carry-out station  2 , the peeling process station  3 , the transfer station  7 , and a post-treatment station  310 . In the peeling system  320 , since a wafer to be processed W is handled before the thinning process, the second cleaning device  33  shown in  FIG. 15  may service as the first cleaning device  31 . 
         [0115]    The post-treatment station  310 , which treats a peeled-off wafer to be processed W before being polished, i.e., an abnormal wafer to be processed W that is detected to have a defect in the inspection process, is provided adjacent to the transfer station  7 . A gas flow, which is vertically downward and is referred to as a downflow, is generated inside the post-treatment station  310 . An internal atmosphere of the post-treatment station  4  is exhausted through an exhaust port (not shown). 
         [0116]    In the peeling system  320 , a pressure within the post-treatment station  310  is set to be lower than a pressure within the transfer station  7 . This causes a gas flow from the transfer station  7  to the post-treatment station  310 . A relationship between the pressure within the transfer station  7  and the pressure within the peeling process station  3  is similar to that of the aforementioned peeling system  1 , and thus a description thereof will be omitted to avoid duplication. 
         [0117]    The wafer to be processed W peeled by the peeling device  30  is transferred to the post-treatment station  310  by the transfer mechanism of the transfer station  7  where the peeled-off wafer to be processed W is subjected to a predetermined process. 
         [0118]    According to the above embodiments, no particle is discharged from the peeling device  30  to the transfer station  7  side. Accordingly, it is possible to prevent the particles generated during the peeling process from being spread to the outside of the peeling device  30 . In addition, since gas flows which are oriented from the transfer station  7  to the peeling process station  3  and the post-treatment station  310  are respectively generated, it is possible to prevent the particles from being attached to the overlapped wafer T, the wafer to be processed W, and the support wafer S during the transfer. 
         [0119]    In  FIGS. 8 and 15 , in actual, openings (not shown) through which wafers pass are formed at portions of a sidewall at which white arrows are positioned. Through these openings, the gas flows in the directions of the white arrows as shown in  FIGS. 8 and 15 . 
         [0120]    While in the above embodiments, the cassette C W  configured to accommodate the wafers to be processed W after the processing has been described to be disposed in the carry-in/carry-out station  2 , the present disclosure is not limited thereto. As an example, as shown in  FIG. 16 , a loading table  400  on which the cassette C W  is loaded may be disposed in the post-treatment station  4 . This configuration allows the post-treatment station  4  to directly collect a finally processed wafer W therein, without transferring the finally processed wafer W to the carry-in/carry-out station  2 . Further, since the pressure within the post-treatment station  4  is set to be higher than those of the other stations, there is no apprehension of dust entering the post-treatment station  4  from other stations. This makes it possible to collect the finally processed wafer W while maintaining a clean state. 
         [0121]    In some embodiments, a configuration as shown in  FIG. 17  may be employed as a modified example of  FIG. 8 . Differences between the configurations of  FIG. 17  and  FIG. 8  will be described. In  FIG. 17 , the cleaning device  31  does not contain an opening through which the wafer to be processed W passes at a sidewall facing the transfer station  7 . In the cleaning device  31 , openings through which the wafer to be processed W passes are formed at only sidewalls facing the transfer unit  32  and the interface station  5 . Carrying the wafer to be processed W in and out of the cleaning device  31  is performed through the two openings of the transfer unit  32  or the transfer mechanism  41 . This configuration makes it possible to simplify a configuration of the cleaning device  31  shown in  FIG. 17  compared with that of the device shown in  FIG. 8 , thus improving reliability of the device. 
         [0122]    In some embodiments, a shutter configured to open/close the openings may be installed in the openings. Alternatively, the openings may be always in an open state instead of installing the shutter. 
         [0123]    Next, the reason that the porous chuck is used will be described. The wafer to be processed W is ground by a grinder so as to further slim a thickness thereof. This grinding process is then followed by the peeling process in the peeling system  1 . In the peeling process, a thickness of the wafer to be processed W is, for example, about 40 μm. When peeling off the wafer to be processed W, the substantially entire region thereof should be held. Otherwise, after the peeling process, the wafer to be processed W would be warped and rounded like, e.g., a rolled paper. Addressing this problem requires the porous chuck which adsorbs the substantially entire region of the wafer to be processed W. 
         [0124]    Next, the reason that the Bernoulli chuck is used as the transfer mechanism for the wafer to be processed W will be described. When the wafer to be processed W is subjected to the peeling process, the bonding surface W J  thereof is exposed, and the adhesive G is attached onto the exposed bonding surface W J . When the transfer mechanism transfers the wafer to be processed W while holding the bonding surface W J  thereof in a contact manner, the adhesive G may be attached onto the transfer mechanism, thereby making the transfer mechanism dirty. As such, the Bernoulli chuck is used as a holding unit for holding the wafer to be processed W. The Bernoulli chuck is capable of holding the wafer to be processed W in a state where it floats from the Bernoulli chuck (in a contactless manner). Therefore, the adhesive G is not attached to the Bernoulli chuck and does not make the transfer mechanism dirty. In some embodiments, the Bernoulli chuck may be formed in any shape as long as it can hold the substantially entire region of one surface of the substrate in order to prevent the warpage from occurring in the wafer to be processed W. 
         [0125]    Further, after the wafer to be processed W is separated from the support wafer S, in order to prevent the warpage from occurring in the wafer to be processed W, the substantially entire region of one surface of the wafer to be processed W always needs to be held by the aforementioned porous chuck or Bernoulli chuck. For example, even when the wafer to be processed W is transferred between the porous chuck and the Bernoulli chuck, any one of the chucks necessarily hold the wafer to be processed W over the entire surface thereof. In some embodiments, in the post-treatment station  4 , the wafer to be processed W may be fixed to a frame body for preventing the warpage. 
         [0126]    Furthermore, some portions of the above embodiments may be combined with each other, while obtaining the same operation and effects as the above embodiments. 
         [0127]    Although preferable embodiments of the present disclosure have been described above with reference to the accompanying drawings, the present disclosure is not limited to the embodiments. It should be understood that various changes and modifications are readily apparent to those skilled in the art within the scope of the spirit as set forth in the claims, and those should also be covered by the technical scope of the present disclosure. The present disclosure is not limited to the embodiments but can take various aspects. The present disclosure may be applied to other various substrates including an FPD (flat panel display), a mask reticle for a photomask and so on, in addition to the wafers. 
       EXPLANATION OF REFERENCE NUMERALS 
       [0000]    
       
         
           
               1  peeling system 
               2  carry-in/carry-out station 
               3  peeling process station 
               4  post-treatment station 
               5  interface station 
               6  inspection device 
               7  transfer station 
               8  cleaning device 
               9  wafer transfer region 
               20  transfer mechanism 
               30  peeling device 
               31  first cleaning device 
               32  transfer unit 
               33  second cleaning device 
               41  transfer mechanism 
               100  housing 
               110  first holding unit 
               111  second holding unit 
               124  heating mechanism 
               141  heating mechanism 
               150  moving mechanism 
               151  vertical moving unit 
               152  horizontal moving unit 
               190  porous chuck 
               230  transfer region 
               231  transfer mechanism 
               232  Bernoulli chuck 
               300  control unit 
               310  post-treatment station 
               320  peeling system 
             G adhesive 
             S support wafer 
             T overlapped wafer 
             W wafer to be processed

Technology Category: y