Abstract:
An object of the present invention is to provide a bump-bonding heating apparatus, a bump bonding method and a bump forming apparatus which do not involve large-sized apparatus configuration and which are easy to handle, and a semiconductor wafer in which bumps are formed by using the bump bonding method. The bump-bonding heating apparatus has a wafer turning member, a turning unit and a wafer heating unit. The turning member is turned by the turning unit without turning the wafer heating unit, whereby a semiconductor wafer mounted on the turning member is turned. Like this, since the wafer heating unit is not turned, the apparatus configuration can be made compact. Since the turning member is turned directly by the turning unit, the turning angle of the semiconductor wafer can be implemented with higher precision as compared with the conventional gas floating type turning method.

Description:
This application is a divisional application of application Ser. No. 09/690,746, filed Oct. 18, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a bump-bonding heating apparatus for heating a semiconductor wafer placed on the heating apparatus to a bump bonding temperature in a process of forming bumps at electrode portions on circuits formed on the semiconductor wafer, a bump bonding method to be carried out by using the bump-bonding heating apparatus, a bump forming apparatus equipped with the bump-bonding heating apparatus, and a semiconductor wafer having bumps bonded by the bump forming apparatus. 
     Conventionally, a bump forming apparatus is equipped with the bump-bonding heating apparatus. As shown in FIGS. 24 and 25, in the conventional bump-bonding heating apparatus  1 , gas is jetted out, through gas jet paths  4  opened at a heat stage  2 , to a semiconductor wafer  3  which has been carried into the bump-bonding heating apparatus and placed on the heat stage  2  so that the semiconductor wafer  3  is heated to a bump bonding temperature. By this gas jet, the semiconductor wafer  3  is rotated circumferentially of the semiconductor wafer  3  on the heat stage  2  so as to be set to a preset rotational angle. For such a gas-floating type direct turning method for the semiconductor wafer  3 , only a gas supply unit  5  needs to be provided as a structure for turning the semiconductor wafer  3 . This allows the bump-bonding heating apparatus  1  to be made compact, and thus this direct turning method is preferable. 
     However, the bump-bonding heating apparatus of the above structure has the following problems. That is, in the case where the semiconductor wafer  3  is a charge-producing semiconductor substrate that produces charges from temperature differences due to the heating to the bump bonding temperature or other reasons, the charge-producing semiconductor substrate, when mounted on the heat stage  2 , is electrostatically adhered onto the heat stage  2  by the electrification of the charge-producing semiconductor substrate. Also, in order to turn the semiconductor wafer  3  to the preset rotational angle, it would be necessary to control a pressure, flow rate and the like of the gas jet according to a size and weight of the semiconductor wafer  3 , making the apparatus difficult to handle. It is also difficult to turn the semiconductor wafer  3  to the preset rotational angle at high accuracy. 
     Meanwhile, without adopting the gas-floating type turning method for the semiconductor wafer  3 , a structure in which the heat stage  2  with the semiconductor wafer  3  held thereto is rotated could be conceived. This structure, however, would involve increasing the size of the apparatus, disadvantageously. 
     SUMMARY OF THE INVENTION 
     The present invention having been accomplished with a view to solving these and other problems, an object of the invention is to provide a heating apparatus for bump bonding which does not involve large-sized apparatus configuration and which is easy to handle, a bump bonding method to be executed in the heating apparatus for bump bonding, a bump forming apparatus equipped with the heating apparatus for bump bonding, and a semiconductor wafer having bumps bonded by the bump forming apparatus. 
     In order to achieve the above object, the present invention has the following constitutions. 
     In a first aspect of the invention, there is provided a heating apparatus for bump bonding, comprising: 
     a wafer turning member, on which a semiconductor wafer is placed for bump bonding, for rotating the placed semiconductor wafer on the wafer turning member in a circumferential direction of the wafer; 
     a turning unit for rotating the wafer turning member along the circumferential direction; and 
     a wafer heating unit, on which the wafer turning member is placed, for heating the semiconductor wafer to a bump bonding temperature via the wafer turning member, the wafer heating unit being disposed in spite of the rotation of the wafer turning member. 
     In the first aspect of the invention, the heating apparatus for bump bonding may further comprise a control unit for controlling operation of the turning unit so that the wafer turning member is rotated at a turning angle required for the semiconductor wafer placed on the wafer turning member. 
     In the heating apparatus for bump bonding, the wafer turning member may have a wafer stage on which the semiconductor wafer is placed, and a turntable on which the wafer stage is placed and for holding the wafer stage by suction operation, the turntable being placed on the wafer heating unit. 
     In the heating apparatus for bump bonding, the wafer heating unit may have a turntable mounting plate on which the turntable is placed; a heater inserted and extended along a hole, the hole being formed in the turntable mounting plate along a direction perpendicular to a thicknesswise direction of the turntable mounting plate; and a support member for supporting the turntable mounting plate, the support members extending along a direction perpendicular to both directions of the thicknesswise direction and the extending direction of the heater. 
     In the heating apparatus for bump bonding, the turntable may have teeth formed at a peripheral part of the turntable, and 
     the turning unit comprises a driving source, a gear wheel engaged with the teeth of the turntable, and a rotational-force transmission mechanism for preventing heat of the turntable from transferring to the driving source and for transmitting a driving force generated by the driving source to the gear wheel to thereby turn the gear wheel. 
     The heating apparatus for bump bonding may further comprise a lifter unit for lifting and lowering the wafer turning member between a heating position and a transfer position along a thicknesswise direction of the semiconductor wafer placed on the wafer turning member, 
     the heating position being a position where the wafer turning member makes contact with the wafer heating unit so that the semiconductor wafer is heated to the bump bonding temperature via the wafer turning member, and the transfer position being a position where the wafer turning member is positioned when the wafer turning member is turned. 
     The heating apparatus for bump bonding may further comprise a blow unit for floating the semiconductor wafer placed on the wafer turning member from the wafer turning member by gas blow, and a regulating unit for performing positional regulation of the semiconductor wafer on the wafer turning member while the semiconductor wafer is floating from the wafer turning member. 
     In the heating apparatus for bump bonding, the semiconductor wafer is a wafer on which SAW filter devices are formed, and when the SAW filter devices are formed along a skewed direction which is skewed to a crystal orientation of the wafer prior to formation of the SAW filter devices, the turning angle required for the semiconductor wafer placed on the wafer turning member by operation control of the turning unit is an angle which depends on a difference between the crystal orientation and the skewed direction. 
     In a second aspect of the invention, there is provided a bump bonding method comprising: 
     mounting a semiconductor wafer, on which bumps are to be formed, onto a wafer turning member; 
     turning only the wafer turning member with the semiconductor wafer placed thereon along a circumferential direction of the semiconductor wafer at a turning angle required for the semiconductor wafer without turning a wafer heating unit provided for heating the semiconductor wafer to a bump bonding temperature via the wafer turning member; and 
     after the turning, bonding the bumps on the semiconductor wafer at the bump bonding temperature. 
     In a third aspect of the invention, there is provided a bump forming apparatus which comprises the heating apparatus for bump bonding of the first aspect. 
     In a fourth aspect of the invention, there is provided a semiconductor wafer on which a bump is formed by the bump bonding method of the second aspect. 
     In a fifth aspect of the invention, there is provided a semiconductor wafer on which bumps are formed in a circuit by a process comprising, after forming the circuit along a direction which is different from a crystal orientation of the semiconductor wafer and is skewed with respect to the crystal orientation, turning the semiconductor wafer at an angle which depends on a difference between the crystal orientation and the skewed direction. 
     As described in detail above, according to the heating apparatus for bump bonding in the first aspect of the present invention, as well as to the bump bonding method in the second aspect, the apparatus has a turning member, a turning unit and a wafer heating unit, wherein the turning member is turned by the turning unit without turning the wafer heating unit so that the semiconductor wafer mounted on the turning member is turned. Therefore, since the wafer heating unit is not turned, an apparatus configuration can be made compact. Besides, since the turning member is turned directly by the turning unit, a turning angle of the semiconductor wafer can be implemented with higher accuracy as compared with a conventional gas floating type. 
     Also, in the bump forming apparatus equipped with the aforementioned heating apparatus for bump bonding in the third aspect of the invention, the turning angle of the semiconductor wafer can be controlled with high accuracy as described above. Therefore, bump forming positions on the semiconductor wafer can be controlled with higher accuracy as compared with the conventional apparatus. 
     In the semiconductor wafer of the fourth aspect of the invention, on which bumps are bonded with the aforementioned bump bonding method of the second aspect, the turning angle of the semiconductor wafer can be controlled with high accuracy as described above. Therefore, bumps can be formed at bump forming positions on the semiconductor wafer with higher accuracy as compared with the conventional counterpart. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other aspects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a bump-bonding heating apparatus according to an embodiment of the present invention; 
     FIG. 2 is a sectional view of the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 3 is a perspective view of a bump forming apparatus according to an embodiment of the invention; 
     FIG. 4 is a perspective view showing a wafer stage part provided in the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 5 is a perspective view showing a turntable provided in the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 6 is a perspective view showing a heating unit provided in the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 7 is a perspective view showing guide rollers provided in the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 8 is a perspective view showing a modified example of the guide rollers shown in FIG. 7; 
     FIG. 9 is a perspective view showing a part for lifting and lowering the guide rollers shown in FIG. 1; 
     FIG. 10 is a view in which the turntable and the wafer stage provided in the bump-bonding heating apparatus shown in FIG. 1 are positioned at a heating position; 
     FIG. 11 is a view in which the turntable and the wafer stage provided in the bump-bonding heating apparatus shown in FIG. 1 are positioned at a transfer position; 
     FIG. 12 is a view showing a relationship between the turntable and the guide rollers provided in the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 13 is a perspective view of a wafer regulating unit provided in the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 14 is a flowchart showing operation of the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 15 is a view showing a state in which a wafer is carried into the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 16 is a view of a state that the bump-bonding heating apparatus shown in FIG. 1 is lifted to the transfer position for reception of the wafer; 
     FIG. 17 is a view of a state that the wafer has been received by the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 18 is a view showing a state that the wafer has been received by the bump-bonding heating apparatus shown in FIG.  1  and returned to the heating position; 
     FIG. 19 is a plan view showing a state in which the wafer is mounted on the bump-bonding heating apparatus shown in FIG. 1; 
     FIG. 20 is a view showing a state in which the wafer regulating unit provided in the bump-bonding heating apparatus shown in FIG. 1 performs wafer regulation; 
     FIG. 21 is a plan view showing a state after the wafer regulating operation by the wafer regulating unit provided in the bump-bonding heating apparatus shown in FIG. 1 has been done; 
     FIG. 22 is a view showing a conventional semiconductor wafer in which circuits are formed along the crystal orientation of the semiconductor wafer; 
     FIG. 23 is a view showing a semiconductor wafer in which circuits are formed along a direction skewed with respect to the crystal orientation of the semiconductor wafer; 
     FIG. 24 is a perspective view of a bump-bonding heating apparatus according to a conventional art; and 
     FIG. 25 is a view showing a state in which a wafer is floated by gas jet-out performed in the bump-bonding heating apparatus according to the conventional art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the accompanying drawings. 
     Hereinbelow, a heating apparatus for bump bonding (hereinafter, referred to as “a bump-bonding heating apparatus”) which is an embodiment according to the present invention, a bump bonding method to be carried out by the bump-bonding heating apparatus, a bump forming apparatus equipped with the bump-bonding heating apparatus, and a semiconductor wafer in which bumps are formed by using the bump bonding method are described with reference to the accompanying drawings. 
     In this embodiment, a semiconductor wafer to be processed is exemplified by a charge-producing semiconductor substrate that produces charges, thereby being electrified, due to temperature changes from room temperature to a bump bonding temperature. This embodiment is suitable for a processing of, among others, a wafer-like piezoelectric substrate (hereinafter, referred to as “piezoelectric substrate wafer”) for forming a SAW filter. However, the processing target is not limited to the piezoelectric substrate wafer. The bump-bonding heating apparatus of this embodiment is applicable also to the charge-producing semiconductor substrate, for example, compound semiconductor wafers of LiTaO 3 , LiNbO 3  or the like, quartz semiconductor wafers using a quartz substrate, and the like. Further applicable are Si semicondoctor wafers using a Si substrate. In such a case, the Si wafers is heated to 250° C.-about 270° in a process of forming the bumps. 
     The SAW (Surface Acoustic Wave) filter has been available as a semiconductor device for transferring only signals of specified frequencies. In recent years, however, due to increased numbers of frequencies involved, there have been occurring not only conventional cases, as shown in FIG. 22, where a device  250  is formed along a direction perpendicular to a crystal orientation of the wafer but also cases, as shown in FIG. 23, where a semiconductor wafer  202  in which, for example, the SAW filter devices  250  are formed along a direction skewed with respect to the crystal orientation and moreover bumps  251  are bonded on the devices  250  is fabricated. When the bumps are formed on such the wafer in which the device is formed along the skewed direction, there arises a need of turning the wafer to an extent corresponding to a skewed angle, which depends on a difference between the crystal orientation and the skewed direction, in terms of the relation with the movable direction of a bump-forming head. That is, there has been arising a need for turning the wafer at higher accuracy, as compared with the conventional case. The bump-bonding heating apparatus, bump bonding method, and bump forming apparatus of this embodiment are effective especially for semiconductor wafers that need to be turned to the skew angle. 
     As shown in FIG. 1, a bump-bonding heating apparatus  110  of this embodiment, roughly speaking, has a wafer turning member  111 , a turning unit  112 , and a wafer heating unit  113  . The wafer turning member  111 , on which the piezoelectric substrate wafer  201  prior to a bump formation process in which bump bonding is performed (hereinafter, referred to as “bump-unformed wafer”) is mounted, is turned circumferentially of the bump-unformed wafer  201  mounted on the wafer turning member  111 . Bumps are formed by a bump-forming head  190  in electrode portions on the bump-unformed wafer  201  mounted on the wafer turning member  111  at the bump bonding temperature, which is about 210° C in this embodiment. Hereinafter, the piezoelectric substrate wafer after the bump formation is referred to as “bump-formed wafer  202 .” 
     The wafer turning member  111  has a metallic, disc-shaped wafer stage  1111  on which the bump-unformed wafer  201  is to be mounted and which is larger in diameter than the bump-unformed wafer  201 , and a metallic, disc-shaped turntable  1112  which is generally equal in size to the wafer stage  1111 . 
     The turntable  1112 , which is manufactured by tempering at a temperature beyond the temperature of 210° C., never exhibits distortion when heated to about the temperature of 210° C. The turntable  1112 , on which the wafer stage  1111  is to be mounted, has teeth  11127  formed over the entire circumference of the turntable  1112  in this embodiment, the teeth  11127  being for mesh with a later-described gear wheel  1122  provided in the turning unit  112 . 
     Also, as shown in FIG. 5, in a mounting surface  11121  of the turntable  1112 , on which the wafer stage  1111  is to be mounted, are formed a first suction groove  11122  larger in diameter and a second suction groove  11123  smaller in diameter, concentrically with each other. The first suction groove  11122  and the second suction groove  11123  are communicated with each other by a communicating portion  11124 . Further, the first suction groove  11122  and the second suction groove  11123  communicate with a suction passage  11126  formed in the turntable  1112 , and air in the first suction groove  11122  and the second suction groove  11123  as well as the suction passage  11126  is sucked up by a suction unit  117  as described later. Therefore, the wafer stage  1111  mounted on the mounting surface  11121  can be sucked to the mounting surface  11121  by the sucking operation of the suction unit  117 . Also, by the first suction groove  11122  and the second suction groove  11123  being formed over the entire circumference of the turntable  1112 , the wafer stage  1111  can be sucked to the mounting surface  11121  uniformly over the entire circumference. 
     The reasons why a construction that the wafer stage  1111  is held to the turntable  1112  by suction like this is adopted are as follows. That is, since the wafer stage  1111  needs to be replaced depending on thickness and size of the semiconductor wafer to be processed, one reason is to facilitate this replacement operation. Besides, whereas the turntable  1112  and the wafer stage  1111  are heated to about 210° C. in order to heat the bump-unformed wafer  201  to the bump bonding temperature of about 210° C. in this embodiment, another reason is to permit thermal expansion of the wafer stage  1111  caused by the heating process. 
     Further, on the mounting surface  11121  of the turntable  1112 , two positioning pins  11125 - 1 ,  11125 - 2  are erectly provided for positioning the wafer stage  1111  to be mounted on the mounting surface  11121 . 
     At a central portion of the turntable  1112  formed in the above way, is attached a T-shaped joint  115  as shown in FIG.  2 . This joint  115  is composed of a disc-shaped fitting portion  1151  buried relative to the turntable  1112 , and a passage forming portion  1152  erectly provided at the fitting portion  1151  and formed integrally with the fitting portion  1151 . With the joint  115  attached to the turntable  1112 , the passage forming portion  1152  protrudes beyond a rear surface  11128  of the turntable  1112 , extending through the heating unit  113  in a rotatable state relative to the heating unit  113  having the turntable  112  mounted on the heating unit  113 , and the passage forming portion  1152  is rotatably fitted to a connecting member  116  at a connecting portion  1153  of the passage forming portion  1152 . 
     The connecting portion  1153  is fixed to a lift plate  120  which is moved up and down between a heating position  1191  and a transfer position  1192  by a lifter unit  119  having, in this embodiment, an air cylinder. The lifter unit  119  is attached to a base plate  114  and controlled in operation by a control unit  180 . It is noted that the lift plate  120  is supported and guided for up-and-down motion by two guide members  121 . 
     When the joint  115  is attached to the turntable  1112 , the fitting portion  1151  of the joint  115  is buried in the turntable  1112  so that the mounting surface  11121  of the turntable  1112  and one end surface  1151   a  of the joint  115  are positioned in the same plane. In the state that the joint  115  is buried in the turntable  1112 , within the joint  115  are provided a gas suction passage  1154  which communicates with the suction passage  11126  in the turntable  1112  and which extends within the passage forming portion  1152  along the passage forming portion  1152 , and a suction blow passage  1155  which communicates with a gas inlet/outlet passage  11115  within the wafer stage  1111  and which extends within the passage forming portion  1152  along the passage forming portion  1152 . 
     The gas suction passage  1154  is connected to the suction unit  117  via the connecting member  116 . The suction unit  117  is controlled in operation by the control unit  180 . Air in the first suction groove  11122  and the second suction groove  11123  is sucked out by operation of the suction unit  117  via the gas suction passage  1154  and the suction passage  11126 . Also, the suction blow passage  1155  is connected to a suction blow unit  118  via the connecting member  116 . The suction blow unit  118  is controlled in operation by the control unit  180 , and gas is sucked or blown through gas inlet/outlet holes  11112  via the suction blow passage  1155  and the gas inlet/outlet passage  11115  by operation of the suction blow unit  118 . 
     The connecting member  116 , and the connecting portion  1153  of the passage forming portion  1152  rotatably fitted to the connecting member  116  as described above, are held airtight with a seal structure using a seal member such as an O-ring. Therefore, gas flowing through the gas suction passage  1154  and the suction blow passage  1155  never leaks outside. 
     The wafer stage  1111  is manufactured by tempering at a temperature beyond the temperature of 210° C., so it will not exhibit warpage by heating to the temperature of about 210° C. Therefore, the wafer stage  1111  can be held to the turntable  1112  by suction as described above. Also, at the mounting surface  11111  of the wafer stage  1111 , on which the bump-unformed wafer  201  is to be mounted, as shown in FIG. 4, are opened the gas inlet/outlet holes  11112  for sucking and blowing the bump-unformed wafer  201 . Further at the mounting surface  11111 , an escape groove  11113  into which holding claws  1412  of a wafer holding part  1411  holding the bump-unformed wafer  201  enter when the bump-unformed wafer  201  is mounted onto the mounting surface  11111 . Further, provided at the mounting surface  11111  are two positioning rollers  11114  with which an orientation flat portion of the bump-unformed wafer  201  mounted on the mounting surface  11111  makes contact, and which are used for regulating the bump-unformed wafer  201 . The gas inlet/outlet holes  11112  communicate with the gas inlet/outlet passage  11115  formed in the wafer stage  1111 . 
     In a rear surface  11116  of the wafer stage  1111  confronting the mounting surface  11111 , are formed pin insertion holes  11117 - 1 ,  11117 - 2  in correspondence to the positioning pins  11125 - 1 ,  11125 - 2  erectly provided on the turntable  1112 . The pin insertion hole  11117 - 1  has a cylindrical shape having such a hole diameter as to fit to the positioning pin  11125 - 1 , and the pin insertion hole  11117 - 2  has an elongated hole shape extending along a direction of the diameter of the wafer stage  1111 . This is intended to allow any thermal expansion of the wafer stage  1111 , which is caused by the heating of the wafer stage  1111  to the temperature of about 210° C., to be absorbed. 
     By the arrangements that the wafer stage  1111  is held by suction to the turntable  1112  and that the pin insertion hole  11117 - 2  is elongated, as described above, the wafer stage  1111  is allowed to freely stretch even when heated tot he temperature of about 210° C., and is thus free from occurrence of any deformations which would occur if the stretching was restricted. Accordingly, the entire rear surface  11116  of the wafer stage  1111  is permitted to make contact with the mounting surface  11121  of the turntable  1112 , so that temperature of the wafer stage  1111  becomes generally uniform over the entire wafer stage  1111 . Therefore, the bump-uniformed wafer  201  mounted on the wafer stage  1111  can be heated generally uniformly. 
     The wafer heating unit  113 , on which the turntable  1112  is mounted as described above, heats the bump-unformed wafer  201  to the bump bonding temperature via the turntable  1112  and the wafer stage  1111  of the wafer turning member  111 . Also, as described later, whereas the wafer turning member  111  is turned circumferentially by the turning unit  112 , the wafer heating unit  113  is inhibited from turning in the meantime. 
     The wafer heating unit  113 , as shown in FIG. 6, has a turntable mounting plate  1131  on which the turntable  1112  is to be mounted, heaters  1132 , and support members  1133 . To the turntable mounting plate  1131 , as shown in FIG. 6, is connected a suction device  11311  which is controlled in operation by the control unit  180 , and the turntable  1112  mounted on the turntable mounting plate  1131  is held on the turntable mounting plate  1131  by suction operation of the suction device  11311 . The heaters  1132  are heaters of cartridge type, in this embodiment, each of which is inserted into a hole  1134  formed in the turntable mounting plate  1131  along a direction perpendicular to the thicknesswise direction of the turntable mounting plate  1131 , and four heaters  1132  are arranged in parallel to one another in this embodiment. The support members  1133  are members for supporting the turntable mounting plate  1131  onto the base plate  114  of the bump-bonding heating apparatus  110 . 
     The turntable mounting plate  1131  is heated by the heating of the heaters  1132 , and heat of the turntable mounting plate  1131  is transferred to the turntable  1112  while part of the heat is transferred also to the support members  1133 . In this case, if the support members  1133  are arranged so as to extend in the same direction as an extended direction of the heaters  1132 , heat of heaters  1132  closer to the support members  1133  would be more likely to be transferred to the support members  1133 , as compared with heat of heaters  1132  farther from the support members  1133 . Therefore, the turntable mounting plate  1131  would not become generally uniform in temperature as a whole, causing a problem that the turntable  1112  mounted on the turntable mounting plate  1131  and besides the bump-unformed wafer  201  would not become generally uniform in temperature as a whole. Moreover, it is difficult for the heaters  1132  to produce heat generally uniformly over their entire lengths at the beginning of heating, with the result that each of the heaters  1132  would be lower in temperature at its two end portions than at its central portion. 
     This being the case, in this embodiment, in order that heat transfer from the heaters  1132  to the support members  1133  is not biased and that the entire turntable mounting plate  1131  becomes generally uniform in temperature as a whole, the support members  1133  are arranged so as to extend along a direction perpendicular to the thicknesswise direction of the turntable mounting plate  1131  and the extended direction of the heaters  1132 , and in correspondence to the two end portions of each of the individual heaters  1132 . 
     By such a constitution, heat is transferred from each of the four heaters  1132  to the support members  1133 , so that the whole turntable mounting plate  1131  can be brought into a generally uniform temperature, and that the whole bump-unformed wafer  201  can be brought into a generally uniform temperature. 
     The turning unit  112  has a driving source  1121 , a gear wheel  1122 , and a rotational-force transmission mechanism  1123 . The driving source  1121  is implemented by a servomotor in this embodiment and controlled in operation by the control unit  180 . The gear wheel  1122  is meshed with the teeth  11127  of the turntable  1112 . The rotational-force transmission mechanism  1123  prevents the heat of the turntable  1112  from transferring to the driving source  1121  and transmits driving force generated by the driving source  1121  to the gear wheel  1122  to thereby rotate the gear wheel  1122 . In this embodiment, a timing belt is used as the rotational-force transmission mechanism  1123 , but the mechanism is not limited to this structure. 
     In the lift plate  120  that is moved up and down between the heating position  1191  and the transfer position  1192  by the lifter unit  119 , as shown in FIGS. 9 to  11 , four stays  123  are erectly provided in correspondence to four places so as to be circumferentially and equidistantly spaced from one another around the turntable  1112 . At a tip end of each stay  123 , a guide roller  122  is rotatably supported by each stay  123 . The guide roller  122  is to mesh with the teeth  11127  formed at the periphery of the turntable  1112  and moves the turntable  1112  up and down between the heating position  1191  and the transfer position  1192  in correspondence to up and down movement of the lift plate  120 . 
     As shown in FIG. 7, each guide roller  122  is so structured that a cylindrical body rotatably supported on the stay  123  by bearings  1225 , and a lower flange  1221  and an upper flange  1222  protruding diametrically of the cylindrical body at its lower and upper end portions, are integrally formed, and that pins  1223  are provided between the lower flange  1221  and the upper flange  1222  at peripheral portions of the lower flange  1221  and the upper flange  1222 . A pitch of the pins  1223  arranged along the peripheries of the lower flange  1221  and the upper flange  1222  is equal to a pitch of the teeth  11127  of the turntable  1112 . Therefore, in response to the rotation of the turntable  1112  by operation of the turning unit  112 , each guide roller  122  also rotates. 
     Each guide roller  122  constructed as described above prevents the turntable  1112  from shifting diametrically on the turntable mounting plate  1131 , and moves the turntable  1112  up and down as described above by the contact of the lower flange  1221  with the teeth  11127  of the turntable  1112 . 
     With the aformentioned functions of the guide roller  122 , the guide roller  122  does not necessarily need to turn in one-to-one correspondence together with the turnable  1112 . So it is also possible that, as shown in FIG. 8, a lower flange and the teeth  11127  of the turnable  1112  are brought into contact with each other without providing the pins  1223 . With this structure, however, since a guide roller may not rotate in one-to-one correspondence with the rotation of the turnable  1112 , the result is that the lower flange and the teeth  11127  rub more with each other that in the case of the guide roller  122  of the embodiment. Therefore, because of a higher likelohood of production of dust due to wear, there araise a need of some additional contermeasure for dust. 
     Although the guide roller  122  of this embodiment has less generation of dust as described above, anticorrosion, heatproof quenched steel is used for the lower flange  1221  so that the generation of dust is further reduced. 
     Also, as shown in FIG. 12, when the turntable  1112  is rotated by the gear wheel  1122  of the turning unit  112 , the four guide rollers  122  are so structured that each of two guide rollers  122 - 1  positioned farther from the gear wheel  1122  has no gap generated between a root of the teeth  11127  of the turntable  1112  and the pin  1223  engaged with the root, and that, on the other hand, each of two guide rollers  122 - 2  positioned closer to the gear wheel  1122  has a gap generated between the root of the teeth  11127  of the turntable  1112  and the pin  1223 . It is noted that in this embodiment, the gaps  1226  are set each to 0.27 mm in the diametral direction of the turntable  1112  at ordinary temperature. 
     Whereas the turntable  1112  is heated to about 210° C. as described above, provision of the gaps  1226  allows thermal expansions of the turntable  1112  due to heat. This produces an effect of preventing the turntable  1112  from deformation such as warpage so that the turntable  1112  becomes generally uniform in temperature as a whole, and therefore that the bump-unformed wafer  201  on the wafer stage  1111  becomes generally uniform in temperature as a whole. 
     Further in the bump-bonding heating apparatus  110 , a wafer regulation unit  125  is provided, as shown in FIGS. 3 and 13, in order to set the bump-unformed wafer  201  to a specified position on the wafer stage  1111  when the bump-unformed wafer  201  is mounted onto the wafer stage  1111 . The wafer regulating unit  125  has two regulating rollers  1252  making contact with a rim of the bump-unformed wafer  201  placed on the wafer stage  1111 , and a driver part  1251  which moves the regulating rollers  1252  diametrically of the bump-unformed wafer  201  and which is controlled in operation by the control unit  180 . 
     The bump forming apparatus  101  has, roughly speaking, one bump-bonding heating apparatus  110  as described above, one bump-forming head  190 , a carrier unit  130 , a transfer units  140  provided on carriage-in and -out sides respectively, lifter units  151 ,  152  provided for the containers respectively, to lift those respective containers a pre-heater unit  160 , a post-heater unit  170 , and a control unit  180 . 
     The bump-forming head  190  is a device for forming a bump at the electrode of the bump-unformed wafer  201  mounted to the bump-bonding heating apparatus  110  and heated to the bump bonding temperature. The bump-forming head  190  has a wire feed portion  191  for feeding gold wire serving as a bump material, and besides a bump forming portion for forming a ball by melting the gold wire and then pressing the melting ball to the electrode, an ultrasonic generator for making ultrasonic waves act on the bump at the time of the pressing, and the like. The bump-forming head  190  as constructed above is placed on an X-Y table  192  having, for example, a ball screw structure and being movable in X- and Y-directions perpendicular to each other on a plane. The bump-forming head  190  is moved in the X- and Y-directions by the X-Y table  192  so that the bump can be formed at each of the electrodes of the bump-unformed wafer  201  placed and fixed on the X-Y table  192 . 
     The bump forming apparatus  101  is equipped with two kinds of carrier units  130 . A carriage-in unit  131 , which is one of the carrier units  130 , is a device for extracting the bump-unformed wafer  201  from the first container, and a carriage-out unit  132 , the other one, is a device for carrying the bump-formed wafer  202  after bump formation to the second container and accommodating the wafer therein. The carriage-out unit  132  has the same structure and operates in the same manner, as the carriage-in unit  131 . 
     At a place where the carriage-in unit  131  is disposed, is provided an orientation flat alignment unit  133  for orienting the orientation flat of the bump-unformed wafer  201  taken out of the first container  205  by the carriage-in unit  131  along a specified direction. 
     In the pre-heater unit  160 , the bump-unformed after  201  transferring from the carriage-in unit  131  and held by the holding part  1411  is mounted on the pre-heater unit  160 , and then the pre-heater unit  160  increases the temperature of the bump-unformed wafer  201  from room temperature to the bump bonding temperature of about 210° C., at which bump formation is performed, with the bump-bonding heating apparatus  110 . 
     In the post-heater unit  170 , after the bump formation, the bump-formed wafer  202  transferring from the bump-bonding heating apparatus  110  and held by the wafer holding portion  1421  is mounted on the post-heater unit  170 , and then the post-heater unit  170  decreases gradually the temperature of the bump-formed wafer  202  from the bump bonding temperature of about 210° C. to around room temperature. 
     Although the bump forming apparatus of this embodiment has been shown in a case where the pre-heater unit  160  and the post-heater unit  170  are provided, it is also possible that temperature increasing and decreasing operations from the pre-heating operation to the post-heating operation are performed by the bump-bonding heating apparatus  110  without providing the pre-heater unit  160  and the post-heater unit  170 . 
     Operation of the bump-bonding heating apparatus  110  provided in the bump forming apparatus  101  as described above is explained below. It is noted that the operation is controlled by the control unit  180 . 
     At a step (represented by “S” in the figure)  101  of FIG. 14, as shown in FIG. 15, the bump-unformed wafer  201  held by the holding part  1411  is carried from the pre-heater unit  160  into the bump-bonding heating apparatus  110  as described above. 
     At the next step  102 , suction operation by the suction device  11311  that the turntable  1112  is sucked to the turntable mounting plate  1131  provided in the heating unit  113  is halted. Before the halt of the sucking operation, the turntable  1112  and the wafer stage  1111  have already been increased in temperature to about 210° C. by the heating apparatus  110 . 
     At the next step  103 , the lifter unit  119  is operated so that the lift plate  120  is lifted from the heating position  1191  toward the transfer position  1192 . By this lifting operation, the connecting member  116  fixed to the lift plate  120 , and the guide rollers  122  rotatably supported on the stays  123  erectly provided on the lift plate  120  are lifted together concurrently. By the guide rollers  122  being lifted, as shown in FIG. 11, the turntable  1112 , on which the wafer stage  1111  is mounted, is lifted up to the transfer position  1192  via the teeth  11127  making contact with the lower flanges  1221  of the guide rollers  122 . In addition, since the joint  115  fixed to the turntable  1112  is also lifted along with the turntable  1112 , the connecting member  116  and the connecting portion  1153  of the joint  115  are lifted integrally together without exhibiting positional shifts in the up-and-down direction. Further since lowering operation is similar to the lifting operation, the connecting member  116  and the connecting portion  1153  of the joint  115  never exhibits positional shifts in the up-and-down direction. 
     By the wafer stage  1111  having reached the transfer position  1192  at the step  103 , the wafer stage  1111  comes into contact with the bump-unformed wafer  201  held by the holding part  1411  at step  104  as shown in FIGS. 16 and 19, where the bump-unformed wafer  201  is received onto the wafer stage  1111  and mounted onto the wafer stage  1111 . 
     In this state, at step  105 , a position-regulating operation of the bump-unformed wafer  201  on the wafer stage  1111  is performed. That is, as shown in FIG. 17, the holding claws  1412  of the holding part  1411  are opened and then the bump-unformed wafer  201  is released from being held. Further the suction blow unit  118  operates so that a gas, which is clean air or nitrogen gas in this embodiment, is jetted out through the gas inlet/outlet holes  11112  of the wafer stage  1111  via the suction blow passage  1155  and the gas inlet/outlet passage  11115 . In the blowing operation, since the bump-unformed wafer  201  has been preheated, the jetted-out gas has been heated to such a temperature as to hardly lower the temperature of the bump-unformed wafer  201 . 
     By the jet-out of the gas, the bump-unformed wafer  201  is floated about 0.5 mm from the wafer stage  1111 . While the bump-unformed wafer  201  is floating, the regulating rollers  1252  of the wafer regulating unit  125  are moved diametrically of the bump-unformed wafer  201  by the drive part  1251  as shown in FIG.  20  and then come into contact with the rim of the bump-unformed wafer  201 . And then the regulating rollers  1252  push forward the bump-unformed wafer  201  until the orientation flat of the bump-unformed wafer  201  makes contact with the positioning rollers  1114 . Thus, the orientation flat of the bump-unformed wafer  201  is regulated so that the orientation flat takes after the positioning rollers  11114 . By this operation, the positional regulation is achieved. 
     After an end of this positional regulation operation, the suction blow unit  118  halts the gas jet-out operation, starting a suction operation. As a result, air is sucked through the gas inlet/outlet holes  11112  by this suction operation, by which the bump-unformed wafer  201  is sucked onto the wafer stage  1111 . 
     At the next step  106 , the driving source  1121  of the turning unit  112  operates, by which the turntable  1112  is rotated to a bonding angle by the gear wheel  1122  as shown in FIG.  21 . It is noted that the bonding angle refers to an angle as follows. That is, since the bump-forming head  190  can be moved only in the X- and Y-directions by the X-Y table  192 , when the bumps are formed on a wafer on which devices are formed in a skewed direction with respect to the crystal orientation of the wafer, it is preferable that either one direction of the X- and Y-directions and the skewed direction are made coincident with each other, because a travel amount of the X-Y table  192  becomes smaller, so that cycle time can be reduced. Therefore, the bonding angle is a rotational angle of the wafer for making one direction and the skewed direction coincident with each other. The one direction is either one direction of the X- and Y-directions, i.e., a crystal orientation of a semiconductor wafer prior to the formation of circuit devices or a direction perpendicular to a direction of the crystal orientation. 
     Also, such bonding angles are stored in a storage part within the control unit  180  according to types of the wafers to be processed, and read out, as required, by the control unit  180 . Then, the control unit  180  controls the operation of the driving source  1121  so that a turn corresponding to the bonding angle is achieved. 
     In this embodiment, as described above, a servomotor is used as the driving source  1121 , and the turntable  1112  having the teeth  11127  for mesh with the gear wheel  1122  is turned by the gear wheel  1122  that is rotated by the servomotor. Therefore, the bump-unformed wafer  201  can be turned with far higher accuracy, as compared with the conventional gas floating type. Accordingly, even if rotation corresponding to the bonding angle is required, the bump-unformed wafer  201  can be rotated with high accuracy. 
     Since the gear wheel  1122  and the teeth  11127  are engaged with each other, there would occur a turning-amount error due to a backlash when the turning operation is performed. Therefore, this embodiment also adopts a known error correcting method such as a method of performing forward and reverse rotations. 
     At the next step  107 , as shown in FIG. 18, the lifter unit  119  is operated so that the lift plate  120  is lowered from the transfer position  1192  toward the heating position  1191 . By this lowering operation, the guide rollers  122  also lower, causing the turntable  1112  to lower, so that the wafer stage  1111  on the turntable  1112  is moved to the heating position  1191 . Then at the next step  108 , the suction device  11311  is operated again so that the turntable  1112  is sucked to the turntable mounting plate  1131  of the heating apparatus  110 . As a result of this, the turntable  1112  is heated again to about 210° C. to make up for a degree to which the turntable  1112  has been cooled by the foregoing lifting operation. Thus the bump-unformed wafer  201  is heated to the bump bonding temperature. It is noted that the bump-unformed wafer  201  has already been heated nearly to the bump bonding temperature by the preheating operation. 
     Then, at the next step  109 , bumps are formed on the electrodes in circuit portions of the bump-unformed wafer  201  by the bump-forming head  190 . After this bump formation, at a step  110 , the bump-formed wafer  202  is carried out from on the wafer stage  1111  by the wafer holding portion  1421  of the carriage-out side transfer device  142 . 
     According to this embodiment, by the provision of the bump-bonding heating apparatus  110 , troublesome factors such as needs of controlling the pressure, flow rate and the like of the jetted-out gas depending on the size and weight of the semiconductor wafer, as involved in the conventional gas floating type, are eliminated, so that the bump forming apparatus becomes easier to handle. Further, the bump-unformed wafer  201  can be rotated with far higher accuracy, as compared with the conventional gas floating type, so that the bump-unformed wafer  201 , even if required to be turned to an extent of the bonding angle, can be rotated with high accuracy. Furthermore, the heating apparatus  110  for heating the turntable  1112  and so on is not rotated, and a compact apparatus configuration can be obtained. 
     Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.