Abstract:
An elastic body approximately throughout a holding region of a semiconductor wafer is provided in a recess at a center of a holding table that holds the semiconductor wafer. An adhesive tape is joined over a rear face of the semiconductor wafer and a ring frame by rolling a joining roller while the elastic body receives and supports a surface of the semiconductor wafer as a circuit surface.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    (1) Field of the Invention 
         [0002]    This invention relates to a semiconductor wafer mounting method and apparatus for joining an adhesive tape (a dicing tape) over a semiconductor wafer (hereinafter, appropriately referred to as a “wafer”) and a ring frame to manufacture a mount frame. 
         [0003]    (2) Description of the Related Art 
         [0004]    High-temperature processing such as gold evaporation is recently performed to a rear face of a thinned wafer through back grinding process. In such case, an adhesive tape joined to a surface of the wafer for circuit protection is separated, and thereafter high-temperature processing is performed. 
         [0005]    The high-temperature processed wafer is transported to a mounting process. In this process, the wafer is adhesively held on the ring frame via the adhesive tape, whereby a mount frame is manufactured. On the other hand, the wafer may be transported to the mounting process with the surface thereof exposed having no adhesive tape for protection. 
         [0006]    Where the wafer is mounted with the circuit surface thereof being exposed, the wafer is placed and held on the holding table such that the circuit surface thereof is directed downward, and the adhesive tape is joined to the rear face thereof. In this case, the following method is known as an example for joining the adhesive tape. That is, the holding table has an annular suction portion formed on an outer periphery thereof, the suction portion having a recess inside. Specifically, the annular suction portion suction-holds an outer periphery of the wafer, and fluid is supplied to the recess for balancing with joining pressure applied on the rear face of the wafer. Consequently, pressure within the recess is controlled. See Japanese Patent Publication No. S62-287639. 
         [0007]    The surface-protection adhesive tape may be joined again to the surface of the wafer for proceeding to the mounting step. 
         [0008]    The outer periphery on the surface of the wafer, however, directly contacts the annular suction portion of the holding table having high rigidity. Bumps formed up to the outer periphery of the wafer may possibly be broken due to contact to the annular suction portion. Moreover, portions except the outer periphery of the wafer do not contact the annular suction portion, which prevents breakage of bumps through the contact. Pressure within the recess, however, needs to be controlled such that the thinned wafer having reduced rigidity may not be bent and deformed greatly, which control is extremely difficult for realization. 
         [0009]    Moreover, where the adhesive tape protects the surface of the wafer, no damage occurs in the surface of the wafer from direct contact thereof to the holding table. The wafer is however nipped with a metal or ceramic holding table having high rigidity and a joining roller. Accordingly, a minute circuit or bumps formed on the surface of the wafer may be deformed or broken. 
       SUMMARY OF THE INVENTION 
       [0010]    This invention has one object to provide a semiconductor wafer mounting method and apparatus for joining an adhesive tape over a semiconductor wafer and a ring frame with high accuracy to manufacture a mount frame without breakage of the semiconductor wafer itself or a circuit or bump formed on a surface of the semiconductor wafer. 
         [0011]    This invention discloses a semiconductor wafer mounting method for joining an adhesive tape over a semiconductor wafer and a ring frame to manufacture a mount frame. The method includes the step of providing an air-permeable elastic body in a holding region of a holding table that suction-holds the semiconductor wafer, and joining the adhesive tape over a rear face of the semiconductor wafer and the ring frame by rolling a joining roller while a circuit surface of the semiconductor wafer is suction-held on the holding table via the elastic body. 
         [0012]    According to this method, the elastic body is deformed elastically due to pressure from the joining roller, and the adhesive tape is joined to the surface of the semiconductor wafer with the restoring force in the elastic body. In this process, the semiconductor wafer does not contact the holding table directly having high rigidity. In other words, the semiconductor wafer elastically held is not bent and deformed greatly. Consequently, suppression may be realized of deformation or breakage in the circuit or bump on the wafer surface. 
         [0013]    This invention may also include a restricting member along an outer periphery of the elastic body. The restricting member restricts displacement of the semiconductor wafer or the joining roller into an adhesive tape pressing direction. 
         [0014]    In such case, pressure of the joining roller may achieve suppression of great bending and deformation in the outer periphery of the semiconductor wafer on a side where joining of the adhesive tape to the semiconductor wafer is initiated or a side on the end of the wafer where the joining is completed. 
         [0015]    Moreover, this invention may include the restricting member that receives and supports the outer periphery of the semiconductor wafer. 
         [0016]    That is, where the semiconductor wafer has a bump formed on the outer periphery on the surface thereof, the semiconductor wafer is held with the outer periphery thereof protruding beyond the elastic body. The adhesive tape may be joined to the outer periphery on the surface of the semiconductor wafer without directly contacting to the holding table having high rigidity. In addition, the restricting member receives and supports the outer periphery of the semiconductor wafer for suppression of great bending and deformation. As a result, effective suppression may be realized of deformation or breakage in the circuit or bump formed on the outer periphery on the surface of the semiconductor wafer. 
         [0017]    Moreover, this invention may include the restricting member provided outside of the semiconductor wafer close to the outer periphery thereof for receiving falling of the joining roller. 
         [0018]    In such case, unnecessary displacement of the joining roller may be prevented in the tape pressing direction outside of the semiconductor wafer. Moreover, great bending and deformation may be suppressed in the outer periphery of the semiconductor wafer. 
         [0019]    Moreover, in this invention, the restricting member is adjustable in level in accordance with the level of the semiconductor wafer. 
         [0020]    In such case, elastic deformation of the elastic body due to pressure in joining of the adhesive tape may be restricted by an appropriate amount in accordance with a thickness of the semiconductor wafer. That is, great bending and deformation may be suppressed of the outer periphery of the semiconductor wafer. The adhesive tape may be joined to the entire rear face of the semiconductor wafer with appropriate pressure. 
         [0021]    This invention also discloses semiconductor wafer mounting apparatus for joining an adhesive tape over a semiconductor wafer and a ring frame to manufacture a mount frame. The apparatus includes a holding table for holding the semiconductor wafer and the ring frame having an elastic body on a holding region of the semiconductor wafer; a joining unit provided with a joining roller for rolling over the semiconductor wafer and the ring frame; and a tape cutting mechanism for cutting the adhesive tape along a contour of the ring frame. 
         [0022]    With this configuration, the above method may suitably be performed. Furthermore, the foregoing configuration preferably includes a restricting member for restricting displacement of the semiconductor wafer or the joining roller in an adhesive tape pressing direction. 
         [0023]    Where the elastic body has a diameter smaller than the semiconductor wafer, the restricting member is configured to receive and support the outer periphery of the semiconductor wafer. The restricting member may be provided outside of the semiconductor wafer close to the outer periphery thereof. Moreover, the restricting member may be molded with an elastic body so as to be adjustable in level. 
         [0024]    Additional features of the invention will be preset forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. 
         [0025]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention. 
           [0027]      FIG. 1  is a plan view of semiconductor wafer mounting apparatus. 
           [0028]      FIG. 2  is a front view of the semiconductor wafer mounting apparatus. 
           [0029]      FIG. 3  is a front view partly showing a workpiece transport device. 
           [0030]      FIG. 4  is a plan view partly showing the workpiece transport device. 
           [0031]      FIG. 5  is a front view of a wafer transport mechanism. 
           [0032]      FIG. 6  is a plan view showing a principal portion of the wafer transport mechanism. 
           [0033]      FIG. 7  is a plan view showing forward/backward movement structures of the wafer transport mechanism and a ring frame transport mechanism. 
           [0034]      FIGS. 8 and 9  are front views each partially showing forward/backward movement structures of the wafer transport mechanism and the ring frame transport mechanism. 
           [0035]      FIG. 10  is a front view of the frame transport mechanism. 
           [0036]      FIG. 11  is a plan view of an adhesive tape joining section. 
           [0037]      FIG. 12  is a front view of the adhesive tape joining section. 
           [0038]      FIG. 13  is a perspective view of a holding table. 
           [0039]      FIG. 14  is a plan view of the holding table. 
           [0040]      FIG. 15  is a longitudinal sectional front view of the holding table that holds a workpiece. 
           [0041]      FIGS. 16  through to  19  are front views each showing an adhesive tape joining process. 
           [0042]      FIG. 20  is a perspective view of a mount frame from a surface thereof. 
           [0043]      FIG. 21  is a perspective view of the mount frame from a rear face thereof. 
           [0044]      FIGS. 22 and 23  are longitudinal sectional front views each showing a holding table in another embodiment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0045]    One embodiment of the present invention is now described below with reference to the drawings. 
         [0046]      FIG. 1  is a plan view of semiconductor wafer mounting apparatus according to this invention.  FIG. 2  is a front view thereof. 
         [0047]    As shown in  FIG. 20 , the semiconductor wafer mounting apparatus joins an adhesive tape DT over a ring frame f and a semiconductor wafer W (hereinafter, simply referred to as a “wafer W”) having an exposed circuit pattern formed on a surface thereof for manufacturing a mount frame MF. 
         [0048]    As shown in  FIGS. 1 and 2 , a workpiece transport device  1  extends horizontally. An adhesive tape joining section  2  is disposed rearward from the center of the workpiece transport device  1 . Herein, the adhesive tape joining section  2  joins the adhesive tape DT to the ring frame f and the wafer W to manufacture the mount frame MF. 
         [0049]    A wafer supply section  4  is disposed at a rightward front side with respect to the center of the longitudinal apparatus. The wafer supply section  4  includes a cassette  3  that houses wafers W in a stack manner for supplying them. Moreover, a frame supply section  6  is disposed at a leftward front side with respect to the center of the longitudinal apparatus. The frame supply section  6  includes a cassette  5  that houses ring frames fin a stack manner for supplying them. Further, a holding table  7  is disposed at a rear side near the center of the apparatus so as to move in a forward/backward direction. Herein, the holding table  7  transfers the wafer W and the ring frame f each placed thereon to the adhesive tape joining section  2 . 
         [0050]    The workpiece transport mechanism  1  includes a wafer transport mechanism  9  and a frame transport mechanism  10 . The wafer transport mechanism  9  is supported at a right side of a guide rail  8  so as to reciprocate horizontally. Herein, the guide rail  8  extends horizontally. The frame transport mechanism  10  is supported at a left side of the guide rail  8  so as to move horizontally. Moreover, an aligner  11  is provided at a rightward rear side of the apparatus. Herein, the aligner  11  performs alignment of the wafer W with a notch or an orientation mark. Further, an aligner  12  is provided at a rear side of the frame supply section  6 , and performs alignment of the ring frame f. 
         [0051]    The wafer transport mechanism  9  pulls out a wafer W from the cassette  3 , and then transports the wafer W in the forward/backward and horizontal directions. Further, the wafer transport mechanism  9  may turn the wafer W upside down.  FIGS. 3 to 9  show a detailed structure of the workpiece transport device  9 . 
         [0052]    As shown in  FIGS. 3 and 4 , the wafer transport mechanism  9  includes a horizontally movable table  14  that moves horizontally along the guide rail  8 . The wafer transport mechanism  9  also includes a forward/backward movable table  16  that moves forward/backward along a guide rail  15  provided in the horizontally movable table  14 . The wafer transport mechanism  9  also includes a wafer holding unit  17  provided below the forward/backward movable table  16  so as to move vertically. 
         [0053]    A driving pulley  19  is pivotally supported near a right end of the guide rail  8  and is driven by a motor  18  so as to rotate forward/backward. Moreover, an idling pulley  20  is pivotally supported near a center of the guide rail  8 . Further, a belt  21  is wound between the driving pulley  19  and the idling pulley  20 . A slide engagement section  14   a  in the horizontally movable table  14  is connected to the belt  21 . Consequently, the belt  21  rotates forward/backward, and accordingly the horizontally movable table  14  moves horizontally. 
         [0054]    As shown in  FIGS. 7 through 9 , a driving pulley  23  is pivotally supported near a rear end of the horizontally movable table  14  and is driven by a motor  22  so as to rotate forward/backward. Moreover, an idling pulley  24  is pivotally supported near a front end of the horizontally movable table  14 . Further, a belt  25  is wound between the driving pulley  23  and the idling pulley  24 . A slide engagement section  16   a  in the forward/backward movable table  16  is connected to the belt  25 . The belt  25  rotates forward/backward, and accordingly the horizontally movable table  16  moves horizontally. 
         [0055]    As shown in  FIG. 5 , the wafer holding unit  17  includes an inverted L-shaped support frame  26 , a lifting table  28 , a turning table  30 , a pivoting motor  32 , a wafer holding arm  34 , and a reverse rotating motor  36 . The support frame  26  is connected to a lower surface of the horizontally movable table  16 . A motor  27  drives the lifting table  28  in a screw feed manner along a vertical frame of the support frame  26 . The turning table  30  is pivotablly supported via a turning axis  29  for pivoting about a vertically oriented axis p. The pivoting motor  32  is wound around the turning axis  29  via a belt  31  for interlocking with each other. The wafer holding arm  34  is supported on a lower surface of the turning table  30  for reverse rotation about a horizontal axis q. The reverse rotating motor  36  is wound around the turning axis  33  via a belt  35  for interlocking with each other. 
         [0056]    As shown in  FIG. 6 , the wafer holding arm  34  has U-shaped suction portions  34   a  having vacuum suction holes  37  formed therein at a tip end of the wafer holding arm  34 . Use of the movable structure described above may achieve the following advantages. That is, the wafer W suction-held with the wafer holding arm  34  may be moved in forward/backward and horizontal directions, and may be turned about the vertically-oriented axis p with the holding arm  34 . The wafer W may also be turned upside down through the reverse rotation about the horizontally-oriented axis q. 
         [0057]    As shown in  FIG. 2 , a collection section  39  is disposed at a left side of the frame supply section  6  for collecting to stack manufactured mount frames MF. The collection section  39  includes an upright rail  41  coupled to and fixed on an apparatus framework  40 , and a lifting table  43  driven by a motor  42  so as to move vertically in a screw feed manner along the upright rail  41 . Accordingly, the frame supply section  6  allows the mount frame MF to be placed on the lifting table  43  and to move downward in a pitch feed manner. 
         [0058]    The frame transport mechanism  10  pulls out an uppermost one of stacked ring frames f from the frame supply section  6  in succession, and then transports each ring frame fin the horizontal and forward/backward directions. The horizontal and forward/backward movement structures of the ring frame transport device  10  are similar to those of the wafer transport mechanism  9 . 
         [0059]    As shown in  FIGS. 7 and 10 , specifically, the frame transport mechanism  10  includes a horizontally movable table  44  that extends and moves horizontally along the guide rail  8 . The frame transport mechanism  10  also includes a forward/backward movable table  46  that moves forward/backward along a guide rail  45  in the horizontally movable table  44 . The ring frame transport device  10  also includes a ring frame holding unit  47  that is provided below the forward/backward movable table  46  so as to move vertically. 
         [0060]    As shown in  FIGS. 3 and 4 , a driving pulley  49  is pivotally supported near a left end of the guide rail  8  and is driven by a motor  48  so as to rotate forward/backward. Moreover, an idling pulley  50  is pivotally supported near the center of the guide rail  8 . Further, a belt  51  is wound between the driving pulley  49  and the idling pulley  50 . A slide engagement section  44   a  in the horizontally movable table  44  is connected to the belt  51 . The belt  51  rotates forward/backward, and accordingly the horizontally movable table  44  moves horizontally. 
         [0061]    Herein, the configuration shown in  FIGS. 7 through 9  for describing the wafer transport mechanism  9  is applied to the description on the frame transport mechanism  10 . That is, a driving pulley  53  is pivotally supported near a rear end of the horizontally movable table  44 , and is driven by a motor  52  so as to rotate forward/backward. Moreover, an idling pulley  54  is pivotally supported near the rear end of horizontally movable table  44 . Further, a belt  55  is wound between the driving pulley  53  and the idling pulley  54 . A slide engagement section  46   a  in the forward/backward movable table  46  is connected to the belt  55 . The belt  55  rotates forward/backward, and accordingly the forward/backward movable table  46  moves forward/backward. 
         [0062]    As shown in  FIG. 10 , the frame holding unit  47  includes an upright frame  56  connected to a bottom side of the forward/backward movable table  46 , a lifting frame  57  supported so as to slide vertically along the upright frame  56 , a bendable link mechanism  58  for moving the lifting frame  57  vertically, a motor  59  for bending the bendable link mechanism  58  forward/backward, and suction pads  60  provided at corners on lower ends of the lifting frame  57 . Accordingly, the suction pads  60  suction-hold stacked ring frames fin order from an uppermost one that are stacked on the lifting table  43 , and then move upward. Thus, the ring frames f may be transported forward/backward and horizontally. Herein, the suction pad  60  may slode horizontally in accordance with a size of a ring frame f. 
         [0063]    The wafer transport apparatus  1  is configured as described above. A wafer W and a ring frame f are transported to the adhesive tape joining section  2  as follows. In the wafer transport mechanism  9 , first, the wafer holding arm  34  suction-holds a wafer W and transports the wafer W to the aligner  11 . Next, the aligner  11  performs alignment of the wafer W placed thereon. After performance of the alignment, the wafer holding arm  34  again suction-holds the wafer W and turns it upside down. The wafer W having the surface directed downward is transported and placed onto the holding table  7 . 
         [0064]    In the frame transport mechanism  10 , on the other hand, each suction pad  60  suction-holds a ring frame f and transports the ring frame f to the aligner  12 . Next, the aligner  12  performs alignment of the ring frame f placed thereon. Next, each suction pad  60  again suction-holds the ring frame f subjected to the alignment, transfers the ring frame f to the holding table  7 , and places the ring frame f on the holding table  7  such that the ring frame f is concentric with the wafer W. 
         [0065]    As shown in  FIGS. 11 and 12 , the adhesive tape joining section  2  includes a tape supply section  61  that houses a wide adhesive tape (a dicing tape) DT in a roll form, a joining roller  62 , a separation roller  63 , a tape cutting mechanism  64 , and a tape collection section  65 .  FIGS. 16 to 19  are schematic views each showing a proces of joining the adhesive tape DT. 
         [0066]    As shown in  FIG. 16 , the joining roller  62  and the separation roller  63  are in a standby position. Moreover, the tape cutting mechanism  64  is in a standby position. In this state, the holding table  7  having the wafer W directed downward and the ring frame f placed thereon reaches a tape joining position. 
         [0067]    Subsequently, as shown in  FIG. 17 , the joining roller  62  in its standby position moves forward to join the adhesive tape DT over the wafer W and the ring frame f. Upon completion of joining the adhesive tape DT, a round blade  64   a  in the tape cutting mechanism  64  moves downward and turns about an axis x concentric with the wafer W, as shown in  FIG. 18 . The round blade  64   a  turns to cut the adhesive tape DT joined to the ring frame f into a circle having a diameter larger than the inner diameter of the ring frame f. Thereafter, the separation roller  63  rolls forward as shown in  FIG. 19  to separate an unnecessary portion of the cut adhesive tape DT located outside a cutting line from the ring frame f. Accordingly, the mount frame MF directed downward remains on the holding table  7 , as shown in  FIG. 21 . The holding table  7  having downward-directed mount frame MF held thereon moves from the tape joining position toward a front side with respect to the apparatus. Meanwhile, each of the joining roller  62  and the separation roller  63  returns to its initial position. Simultaneously, the adhesive tape DT fed out from the tape supply section  61  is supplied above the tape joining position, whereas an unnecessary tape t to is wound and collected in the tape collecting section  65 . 
         [0068]    Each of  FIGS. 13 to 15  shows a detail configuration of the holding table  7  in the adhesive tape joining section  2 . 
         [0069]    The holding table  7  has a wafer supporting pedestal  71  and a frame holder  72 . The wafer supporting pedestal  71  in a circular shape is mounted and connected onto a base  70 . The frame holder  72  in an annular shape surrounds the wafer supporting pedestal  71 . 
         [0070]    The wafer supporting pedestal  71  has a circular recess on the upper surface thereof. The recess has an elastic body  73  fitted thereinto having a slightly smaller diameter than the outer diameter of the wafer W. The elastic body  73  is composed of a closed-cell foamed rubber sponge or a silicon rubber having a thickness of several millimeters. The elastic body  73  has a pair of engaging holes  74  formed close to the center thereof for fixation into alignment pins  75  provided on the upper surface of the holding table. Here, the elastic body  73  is held at a constant attitude of protruding through the surface of the table. In addition, an adjustment sheet  76  is covered under the elastic body  73  so as to have any thicknesses for adjusting the level of the upper surface of the elastic body  73  in accordance with the thickness of the wafer. The adjustment allows the upper surface of the wafer W on the elastic body  73  to have a level slightly higher than that of the ring frame f on the frame holder  72 . 
         [0071]    The elastic body  73  and the adjustment sheet  76  have suction holes  77  formed therein. The suction holes  77  are in communication with a vacuum device via suction grooves  78  formed on the upper surface of the table. Consequently, the wafer W may be suction-held on the upper surface of the elastic body  73 . 
         [0072]    An annular restricting member  79  is placed close to the outer periphery of the elastic body  73  adjacent to the outer periphery on the upper surface of the wafer supporting pedestal  71 . The restricting member  79  is formed of a silicon rubber having appropriate elasticity. The restricting member  79  has an upper surface that is directed toward the lower surface of the outer periphery of the wafer W protruding beyond the elastic body  73 . 
         [0073]    The frame holder  72  has a step  80  formed on the upper surface thereof with the same contour as the ring frame f. Fitting of the ring frame f into the step  80  may realize concentric alignment of the ring frame f with the wafer W. 
         [0074]    The holding table  7  is configured as following. In the adhesive tape joining process mentioned above, the elastic body  73  is deformed elastically due to pressure from the joining roller  62 . According to the elastic deformation, the wafer W falls into a level equal to that of the ring frame f. That is, the adhesive tape DT is joined to the upper surface (rear surface) of the wafer with given pressure. 
         [0075]    Moreover, the restricting member  79  receives a portion of the wafer W protruding beyond the outer periphery thereof that occurs due to falling of the wafer W. Accordingly, the restoring force in the restricting member may restrict falling of the portion projecting beyond the outer periphery of the wafer W below the level of the upper surface of the ring frame f. 
         [0076]    According to the apparatus in the foregoing exemplary embodiment, the elastic body  73  and the restriction member  79  receive the wafer W, whereby damages may be suppressed occurring from improper falling of the outer periphery of the wafer adjacent to the adhesive tape joining start position to the wafer W. 
         [0077]    This invention may be embodied as follows. 
         [0078]      FIG. 22  shows one embodiment of the holding table  7  suitable in a case where the wafer surface has bumps on the outer periphery thereof. 
         [0079]    In this case, the elastic body  73  has a diameter equal or slightly larger than the outer diameter of the wafer W such that the outer periphery on the surface of the wafer W does not protrude. Moreover, the annular restricting member  79  is arranged adjacent outside of the wafer W to surround the elastic body  73 . Here, the restriction member  79  has the upper surface subject to a non-adhesive treatment so as to remove the adhesive tape DT readily. The restricting member  79  also restricts falling of the joining roller  62 . That is, pressure of the joining roller  62  may prevent the outer periphery of the wafer W from being greatly bent and deformed. 
         [0080]    The restricting member  79  is attached so as to be adjustable in level through an adjustment bolt  81 . Specifically, the position in level of the upper surface of the restricting member  79  is adjusted in accordance with the thickness of the wafer W, whereby the downward displacement amount of the wafer W may be restricted during joining of the adhesive tape DT. Adjustment of the displacement amount may realize uniform joining of the adhesive tape DT over the rear surface of the wafer W with appropriate pressure. 
         [0081]      FIG. 23  shows another embodiment of the holding table  7  suitable in a case where the wafer surface has bumps on the outer periphery thereof. 
         [0082]    Here in this case, the base  70  is configured adjustable in vertical position, and the restriction member  79  is attached to the fixed frame holder  72 . That is, level adjustment of the wafer supporting pedestal  71  may perform positional adjustment of the upper surface of the restricting member  79  in accordance with the thickness of the wafer. In this configuration, the restricting member  79  also restricts falling of the joining roller  62 . Consequently, the outer periphery of the wafer W may be prevented from being greatly bent and deformed. Moreover, the downward displacement amount of the wafer W may be restricted during joining of the adhesive tape DT. Adjustment of the displacement amount may realize uniform joining of the adhesive tape DT over the rear surface of the wafer W with appropriate pressure. 
         [0083]    According to the apparatus in the foregoing exemplary embodiment, a closed-cell foamed rubber sponge having high air-permeability only in a thickness direction may be used as the elastic body. In this case, the wafer W may be suction-held on the entire surface of the elastic body  73  having no suction-hole  77  formed therein. Here, the closed-cell foamed rubber sponge has air-permeability only in a vertical direction. Consequently, no suction force from the outer periphery may occur in suction-holding of the wafer via the closed-cell formed rubber sponge. 
         [0084]    The foregoing exemplary embodiment may have an aspect of suction-holding the wafer W and the ring frame f on the under surface of the holding table  7  for joining the adhesive tape from below. 
         [0085]    This invention is applicable to a case where mounting process is performed to a wafer W having a circuit-protection adhesive tape joined to a surface thereof. 
         [0086]    It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.