JP5851719B2 - Method of mounting conductive ball on workpiece using mask - Google Patents

Description

  The present invention relates to a method for mounting a conductive ball on a workpiece using a mask.

  In Patent Document 1, a synthetic resin mold body for sealing a chip is formed on the upper surface of a substrate, and bumps of an electronic component formed by forming bumps on the lower surface of the substrate are bonded to electrodes of a printed circuit board and heated and melted. In the electronic component mounting method that is fixed and fixed, the electronic component mounting method that can eliminate the occurrence of defective fixing due to warpage of the electronic component is described. In Patent Document 1, the correlation between the warpage of the electronic component and the heating temperature due to the difference in the thermal expansion coefficient between the substrate and the mold body is obtained, and the bonding failure rate between the warpage and the bump and the electrode of the printed circuit board is calculated. It is described that a correlation is obtained, a heating temperature at which a bonding failure caused by warpage of the electronic component does not occur is obtained from the correlation, and the electronic component is heated to a temperature higher than the heating temperature to melt the bump and adhere to the electrode. ing.

Japanese Patent Laid-Open No. 08-236918

  A stacked semiconductor device (semiconductor device) has a warp due to non-uniformity of each mounted semiconductor device (chip) and / or non-uniformity due to the wiring density of an interposer mounting the chip.

  The warpage of a stacked semiconductor device or a substrate with multiple semiconductor devices connected is not only when mounting the semiconductor device on a printed circuit board by reflow etc., but also mounting conductive balls such as solder balls using a mask ( Mounting) and manufacturing semiconductor devices, it is becoming a problem. That is, in the process of manufacturing a semiconductor device, in recent years, a small conductive ball, for example, a diameter of 1 mm or less, specifically, 10 mm or less by a mask functioning as a template having a plurality of openings for mounting conductive balls. It has been studied to employ a method of mounting conductive balls of about ˜500 μm on the surface of the substrate. At that time, it is difficult to control the gap between the substrate and the mask only by a slight warp in the semiconductor device or the substrate (hereinafter collectively referred to as the substrate), and the gap formed between the mask and the substrate becomes difficult. Conductive balls may enter. These balls may become lost balls and may cause problems such as being arranged at a position shifted from a desired position on the substrate or being arranged at an unnecessary position (becomes a double ball). .

  Furthermore, in recent years, semiconductor packaging technology called coreless or substrate-less has been developed. One type of coreless is to use a structure in which the core is abolished and only a plurality of wiring layers (build-up layers) are stacked instead of a substrate that includes a glass epoxy layer as a core, such as a conventional package substrate (interposer). A silicon chip is mounted and packaged with a sealing resin (mold resin). Although there is no core layer as a support, it tends to warp, but various merits such as suppression of power supply noise and reduction in manufacturing cost are being recognized.

  One type of substrate-less is a wafer level package (WLP), which is a fine-out type WLP that forms a redistribution layer in a wide area exceeding the chip area. In the fine-out type WLP, since the rewiring layer formed of a wiring material such as copper is packaged together with the silicon chip, it is difficult to reduce the warpage of the entire package.

  Therefore, in order to use these substrates or packages as workpieces (workpieces) and to mount conductive balls on them, a technique for mounting conductive balls on the premise that the workpiece is warped is required.

  One aspect of the present invention is a method including mounting a conductive ball on a workpiece through a mask having a plurality of openings for mounting the conductive ball, the mounting including at least a lower surface of the workpiece. A moving body that supports a side of the moving body including a mechanism for heating the work, the work is heated against the lower surface of the mask while the mask is cooled by a cooling device along the upper surface of the mask. Moving the filling head to fill each of the plurality of openings in the mask with conductive balls.

  In this method, when the conductive ball is mounted on the workpiece by filling the opening of the mask with the conductive ball, the warp of the workpiece can be reduced by heating the workpiece by the moving body that supports the workpiece. Control of the distance (gap) between the workpiece and the mask is facilitated by suppressing the warpage of the workpiece, but on the other hand, the heated workpiece exists near the mask or the heated workpiece is masked. The temperature of the mask rises because it touches the surface. If the temperature of the mask rises, the accuracy of the mask may decrease due to thermal expansion, the mask may be distorted, the accuracy of the position where the conductive ball is mounted decreases, and the distance between the mask and the workpiece It becomes difficult to control. Therefore, in this method, when the conductive balls are filled with the mask, the predetermined temperature is maintained while heating the workpiece, and further, the mask and the workpiece are suppressed by suppressing the temperature rise of the mask while cooling the mask. The distance between the two is easily controlled and the accuracy of the mask is maintained. Therefore, the occurrence of filling mistakes such as stray balls and double balls can be suppressed.

  Filling preferably includes blowing air to the lower surface of the mask by a cooling device. By blowing and cooling the lower surface of the mask, interference between the filling head moving on the upper surface of the mask and the cooling device, typically a fan or blower, can be avoided. In addition, since the plurality of openings of the mask are closed by the work and the moving body on the lower surface of the mask, it is possible to suppress the conductive balls moving on the upper surface of the mask from being affected by the air blow.

  Further, it is desirable that the filling includes sucking and supporting the workpiece by the moving body. As shown in Patent Document 1, when trying to correct the warp by heating the workpiece, depending on the material and the degree of warp, it is heated to a temperature exceeding 200 ° C, typically 240 ° C or higher. Is desirable. On the other hand, when the workpiece becomes hot, it is not easy to cool the mask to an appropriate temperature, and the temperature distribution of the mask becomes large, which causes distortion and the like.

  In this method, a member packaged as a work, for example, a coreless substrate using an interposer, an epoxy resin, or the like, and a temperature at which a mounted chip is deformed relatively easily, typically 50-100. Warping is mechanically corrected by heating to about ℃ and supporting the workpiece by suction with a moving body. Therefore, the warp of the workpiece can be corrected at a relatively low temperature, and the temperature rise of the mask can be suppressed.

Furthermore, before filling, it includes correcting the warpage of the workpiece by pressing at least a part of the workpiece from above with a correction jig while heating the workpiece mounted on the moving body. Workpiece warpage can be more efficiently corrected by applying pressure with a correction jig. Further, when filling the conductive balls, the workpiece is heated by the moving body and maintained at about 50 to 100 ° C., and further supported by suction, so that the state corrected by the correction jig can be easily maintained. That is, mounting is a moving body that supports at least the lower surface side of the workpiece, and is mounted under the correction jig placed on the lower side of the mask by mounting the workpiece on a moving body including a mechanism for heating the workpiece. Moving, heating the work mounted on the moving body, pressing at least a part of the work from above with a correction jig to correct the warp of the work, and an observation camera from the top of the mask , Observe the reference mark of the mask, observe the reference mark of the work through the window provided on the mask and confirm the position of the work and the mask, and based on the confirmed position of the work and the mask Positioning the workpiece mounted on the moving body and the mask.

  Another aspect of the present invention is a mask having a plurality of openings for mounting conductive balls on a work, and a moving body that supports at least the lower surface side of the work and controls the position of the work with respect to the mask. A moving body that includes a mechanism that heats the workpiece and that faces the lower surface of the mask while the workpiece is heated; and a moving body that moves along the upper surface of the mask and fills each of the plurality of openings of the mask with conductive balls. The ball mounting device includes a filling head and a device for cooling the mask from a position avoiding the moving path of the filling head. In this ball mounting apparatus, a device for cooling the mask is provided so as not to interfere with the movement path of the filling head. Therefore, while the workpiece is heated by the moving body, the filling head is cooled while the mask is cooled by the cooling device. The conductive ball can be filled in the opening of the mask by moving the mask. Therefore, the conductive ball can be mounted on the workpiece while correcting the warp of the workpiece and suppressing the occurrence of the mask distortion, and the generation of the lost ball and the double ball can be suppressed.

The cooling device preferably includes a fan for blowing air toward the lower surface of the mask. Moreover, it is desirable that the moving body includes a function of sucking and supporting the workpiece. Further, the ball mounting apparatus observes the warp correction jig for pressing at least a part of the work mounted on the moving body on the lower side of the mask from above and the reference mark of the mask from above the mask. And a camera for confirming the position of the workpiece and the mask by observing the reference mark of the workpiece through a window provided in the window.

The perspective view which shows an example of a ball mounting apparatus. The perspective view which shows the outline | summary of a holding table (moving body). Sectional drawing which shows the outline | summary of a filling head. The flowchart which shows the process in which a conductive ball is mounted in a workpiece | work with a ball mounting apparatus. The figure which shows the state which is moving the workpiece | work typically. The figure which shows typically the state which corrects the curvature of a workpiece | work. The figure which shows typically the state which aligned the workpiece | work and a mask and has filled the opening of the mask with the conductive ball | bowl.

  FIG. 1 shows an outline of a ball mounting device (mounting device, ball mounting system, ball mounter) 1. The ball mounting device 1 is a device for mounting a conductive ball (conductive fine particles) by a filling head 5 through a mask 10 at a predetermined position on the workpiece 100. The mask 10 functions as a template having a plurality of openings (opening patterns) 12 for mounting conductive balls at predetermined positions on the workpiece 100.

  Typical examples of the workpiece (workpiece) 100 include a printed wiring board, a semiconductor substrate, and a stacked semiconductor device. Stacked semiconductor substrates are packaged with a chip (semiconductor integrated circuit device) mounted on an interposer and integrated with an appropriate mold resin such as epoxy resin, or packaged with a chip mounted on a coreless substrate. And WLP and the like. The workpiece 100 described below is a stacked semiconductor device, and a plurality of electrodes 102 are formed in a predetermined pattern on a surface (mounting surface) 101 of the workpiece 100, and the ball mounting apparatus 1 includes the plurality of electrodes. A conductive ball is mounted on 102 according to the predetermined pattern.

  The conductive ball mounted on the electrode 102 of the workpiece 100 functions as an electrode (bump) for obtaining an electrical connection, and its diameter is, for example, 1 mm or less, specifically 10 to 10 mm. It is about 500 μm. Such conductive balls are sometimes called microballs, microballs, microparticles, and the like. The conductive balls include solder balls (balls containing silver (Ag), copper (Cu), etc., the main component being tin (Sn)), metal balls such as gold or silver, ceramic balls or plastics. Examples include balls made of conductive balls and the like, and spherical silicon balls used for photoelectric conversion. In recent years, conductive balls are solder balls having a diameter of about 100 μm or less, for example, a diameter of 60 μm.

  A plurality of semiconductor chips are mounted on one surface or both surfaces of the workpiece 100, and a plurality of electrodes 102 for connecting to each semiconductor chip are arranged on one surface 101 of the workpiece 100 in a matrix in a predetermined section 103. They are provided in groups (array form). Therefore, the mask 10 is formed with a plurality of openings 12 divided into a plurality of groups (opening groups) 13 at positions corresponding to the arrangement of the electrodes of the workpiece 100. After the conductive ball is mounted on the workpiece 100 by the ball mounting apparatus 1, the conductive ball is fixed to the workpiece 100 by a reflow furnace or the like. When the workpiece 100 includes a plurality of predetermined configurations, the workpiece 100 is then cut (dized) and provided as a semiconductor device.

  The ball mounting apparatus 1 mounts a base 20, a mask 10 having a plurality of openings 12 as described above, a frame 21 for holding the mask 10 with respect to the base 20, and a work 100. A moving stage 30 for positioning, a filling head 5 that moves the conductive ball along the upper surface 11 of the mask 10 and fills (transfers) the conductive ball into each of the plurality of openings 12 of the mask 10, and a mask 10 and the observation cameras 50a and 50b for observing the workpiece-side reference marks 105a and 105b provided on the workpiece 100, and a cooling device (fan) for cooling the mask 10. ) 60 and the warp of the workpiece 100 mounted on the holding table (support base, moving body) 31 of the moving stage 30 And a correcting jig 70 to correct.

  In FIG. 1, the cooling device 60 and the correction jig 70 are illustrated outside the mask 10 so that the cooling device 60 and the correction jig 70 can be easily seen. It is being fixed to the flame | frame 21 so that it may be located (refer FIGS. 5-7). The correction jig 70 is plate-shaped, and a plurality of windows (openings) 71 are provided so that the workpiece 100 can be pressed from above while avoiding the plurality of electrodes 102 arranged in a matrix. Furthermore, as will be described below, the correction jig 70 includes observation windows 77a and 77b so that the reference marks 105a and 105b of the workpiece 100 can be observed by the observation cameras 50a and 50b, respectively.

  The cooling device (blower device) 60 is arranged to supply cooling air 65 from the lower side of the mask 10 toward the lower side (lower surface) 14 of the mask 10. The cooling device 60 may be a fan that blows air, and is a device that has a mechanism for discharging cooling air 65 or gas toward the lower surface 14 of the mask 10 using an appropriate supply path such as a duct or a pipe. There may be. The cooling device 60 includes a moving stage 30 that moves the workpiece 100 on the lower surface 14 of the mask 10, a filling head 5 that moves to mount a conductive ball on the workpiece 100 using the mask 10 on the upper surface 11 of the mask 10, Although not shown in FIG. 1, it is disposed at a position where it does not interfere with other mechanisms of the ball mounting apparatus 1 such as a mechanism for cleaning the lower surface 14 of the mask 10. That is, the blower 60 is disposed at a position that avoids the movement path of the filling head 5 and the like, and sends air to the mask 10 from that position.

  The observation cameras 50a and 50b observe the mask side reference marks 15a and 15b and the workpiece side reference marks 105a and 105b, respectively. The observation camera 50 a observes the workpiece side reference mark 105 a through an observation window 77 a provided in the correction jig 70 and an observation window 17 a provided in the mask 10. The observation camera 50 b observes the workpiece-side reference mark 105 b through an observation window 77 b provided on the correction jig 70 and an observation window 17 b provided on the mask 10. These observation windows 17 a and 17 b are provided at positions away from the plurality of openings 12 of the mask 10. Further, the correction jig 70 is disposed so as not to interfere with the workpiece 100 when it is set below the plurality of openings 12 of the mask 10 or the openings 12 of the mask 10. The correction jig 70 may be attached so as to move in the horizontal direction with respect to the frame 21 so that the correction jig 70 can be retracted when the workpiece 100 is set below the opening 12 of the mask 10.

  The moving stage 30 includes a holding table (moving body) 31 on which the workpiece 100 is mounted, a Z table 32 that controls the position of the holding table 31 in the height direction with respect to the base 20, and the θ direction (horizontal) of the holding table 31 with respect to the base 20. Direction table) for controlling the angle (rotation angle), the Y table 34 for controlling the position of the holding table 31 relative to the base 20 in the front-rear direction (Y direction), and the holding table 31 relative to the base 20. And an X table 35 for controlling the position in the left-right direction (X direction). Each of the Z table 32, the θ table 33, the Y table 34, and the X table 35 includes a driving motor, and a known method and mechanism such as a ball screw can be used as a moving method. Therefore, the moving stage 30 can freely set the position of the mounted workpiece 100 and the horizontal direction θ with respect to the base 20, and can position the workpiece 100.

  FIG. 2 shows an example of the holding table 31. The holding table 31 is a moving body that supports the lower side (back surface) 104 of the work 100 and moves the work 100 to a predetermined position with respect to the base 20 by the moving stage 30. The holding table 31 includes a suction mechanism 36 that sucks and supports the back surface of the workpiece 100. The suction mechanism 36 includes a suction groove 36b in which a suction hole 36a is disposed, and a pipe 36c connected to the suction hole 36a, and sucks the workpiece 100 by connecting the suction pipe 36c with a vacuum pump (not shown). It can be supported. Further, the suction mechanism 36 is divided into several sections (sections) 36d along the surface 31a of the holding table 31, and when releasing the workpiece 100 from the suction support, the workpieces 100 are sequentially moved from the end section 36d. By releasing, the movement of the conductive ball mounted on the workpiece 100 can be suppressed. All compartments 36d may be released simultaneously.

  Furthermore, the holding table 31 includes a function as a heating device that heats the workpiece 100 and holds it at a predetermined temperature. The holding table 31 is a member having high thermal conductivity such as aluminum or copper, and is sized to ensure an appropriate heat capacity in order to heat (warm) the mounted workpiece 100 to a substantially constant temperature. . Further, one or a plurality of heater insertion holes 38 are provided along the longitudinal direction of the holding table 31, and an electric heater 37 is inserted into the holes 38.

  Further, the suction mechanism 36 provided on the surface 31a of the holding table 31 includes suction grooves 36b formed so as to spread radially outward from the center of each section 36d. Accordingly, the entire surface of the workpiece 100 is sucked and supported by sucking the lower surface of the workpiece 100 along the groove 36b, and the holding table 31 is brought into close contact with the surface 31a of the holding table 31 other than the groove 36b. The contact area with the workpiece 100 is ensured so that the workpiece 100 can be maintained at a uniform temperature as a whole.

  The workpiece 100 movably supported by the holding table 31 includes two reference marks 105a and 105b for positioning at appropriate positions. Therefore, the workpiece 100 is mounted on the holding table 31, and the workpiece 100 is moved to a position where the reference marks 105a and 105b can be observed by the observation cameras 50a and 50b by the moving stage 30, and the workpiece 100 is observed by the observation cameras 50a and 50b. By recognizing the reference marks 105a and 105b, the position (X, Y) and posture (rotation angle) of the workpiece 100 with respect to the reference position of the moving stage 30 are determined. Once the relative position and posture of the workpiece 100 with respect to the moving stage 30, that is, the differences in the X direction, Y direction, and θ direction are found, the workpiece 100 is controlled by controlling the X direction, Y direction, and θ direction of the moving stage 30. The X direction, Y direction, and θ direction can be freely controlled.

  The mask 10 for aligning the workpiece 100 is a thin plate, for example, a metal thin plate having a thickness equal to or smaller than the diameter of the conductive ball (60 μm in this example), and the periphery is reinforced with a reinforcing material (not shown). Furthermore, it is fixed to the mask frame 19. The mask 10 is held by a frame (mask holder) 21 fixed to a base frame 22 integrated with the base 20. For this reason, once the mask 10 is attached to the mask holder 21, the position (X, Y, Z and θ) with respect to the base 20 is fixed. The mask 10 includes reference marks (target marks) 15a and 15b for positioning the mask 10 in addition to the opening 12 for ball mounting (ball filling), and the reference marks 15a and 15b are provided by observation cameras 50a and 50b. , The position of the mask 10 with respect to the base 20 is determined.

  FIG. 3 is an enlarged cross-sectional view showing an example of the filling head 5. The filling head (ball dispenser) 5 is a rotary type, and a wire squeegee 5a arranged at an appropriate pitch along the circumference of the disk 5d is rotated by an axis 5s perpendicular to the mask 10 so that the surface 11 of the mask 10 is covered. The conductive ball B is held in a limited area 18 (moving area). The group of conductive balls B can be held below the filling head 5 by moving the filling head 5 in an appropriate direction, for example, the longitudinal direction (X direction) while rotating the filling head 5. Therefore, the conductive ball B can be moved on the surface 11 of the mask 10 while holding the conductive ball B in a limited range so that the conductive ball B does not escape from the moving area 18 that moves together with the filling head 5. Therefore, the conductive balls B can be concentrated and managed in a limited region (area) where the opening 12 is provided in the surface 11 of the mask 10, and the predetermined position on the lower surface 14 of the mask 10 mounted on the holding table 31. The conductive balls B can be efficiently arranged on the electrodes 102 of the workpiece 100 aligned with each other.

  The filling head 5 is not limited to the rotary type, but is a type that vibrates the squeegee and moves the conductive ball B, a type that includes a cup-shaped member that covers a part of the upper surface 11 of the mask 10, and air. The type of controlling the movement of the conductive ball B using the above gas may be used.

  The ball mounting apparatus 1 further includes a control unit 80 that controls the moving stage 30, the filling head 5, the cameras 50a and 50b, the fan 60, and the like. The control unit 80 includes a CPU and a memory. When the workpiece 100 is manufactured, the process of mounting the conductive ball on the workpiece 100 by the ball mounting apparatus 1 can be controlled using a program. The control unit 80 mounts the workpiece 100 on the holding table 31 and moves the workpiece 100 to a predetermined position below the mask 10 by the moving stage 30 and the heater 37 of the holding table 31 and the holding table 31 and the holding table 31. A function 82 for controlling the temperature of the workpiece 100 mounted on the table 31, a function 83 for correcting warpage of the workpiece 100 mounted on the holding table 31, and a workpiece mounted on the holding table 31 using the cameras 50a and 50b. A function 84 for confirming the position of 100 and a function 85 for filling the opening 12 of the mask 10 with the conductive ball B using the filling head 5. The filling function 85 is made to face the lower surface 14 of the mask 10 while heating the workpiece 100 using the heater 37 of the holding table 31, and further along the upper surface 11 of the mask 10 while cooling the mask 10 by the cooling device 60. Then, the filling head 5 is moved to fill each of the plurality of openings 12 of the mask 10 with the conductive balls B.

  FIG. 4 shows a process of manufacturing the workpiece 100 by mounting the conductive ball B on the workpiece 100 using the ball mounting apparatus 1. 5 to 7 show the movement of the ball mounting apparatus 1 in several steps.

  First, in step 91, as shown in FIG. 5, the work 100 is mounted on the holding table 31 by the function 81 for controlling movement, and the mask 10 is moved by the moving stage 30 while the holding table 31 supports the lower surface 104 of the work 100. The workpiece 100 is moved to the lower side of the lower correction jig 70. When the ball mounting apparatus 1 is incorporated in a system for manufacturing the workpiece 100 together with an apparatus for applying flux to the electrode 102 of the workpiece 100, the moving stage 30 receives the workpiece 100 from the coating apparatus. Further, if the ball mounting apparatus 1 is a system that performs processing alone, the workpiece 100 is picked up by a robot or the like from a line or box for conveying or transporting the workpiece 100 and mounted on the holding table 31 of the moving stage 30.

  The function 82 for controlling the temperature heats the workpiece 100 by the heater 37 built in the holding table 31 and maintains the temperature of the workpiece 100 at 50 to 100 ° C. A workpiece (pre-mold workpiece) 100 in which a semiconductor chip is laminated on an interposer made of glass epoxy resin or the like is warped due to various factors. Furthermore, the workpiece 100 in which the above-described coreless substrate or substrateless packaging is employed includes warpage. Warpage of the workpiece 100 can be corrected to some extent by heating the workpiece 100. For example, the warpage of the workpiece 100 can be corrected by heating to the vicinity of the glass transition temperature of the material included in the workpiece 100 or by heating to a temperature at which the workpiece 100 is heated during reflow, for example, about 200 to 240 ° C. However, it is not recommended to exceed the glass transition temperature (160 to 170 ° C.) of a mold resin such as an epoxy resin that constitutes the workpiece 100. Further, if the temperature exceeds 120 ° C., the flux previously applied to the electrode 102 of the workpiece 100 May soften and cause trouble in mounting the conductive ball B. Therefore, the temperature of the workpiece 100 during ball mounting is preferably maintained at 120 ° C. or lower, and more preferably maintained at 100 ° C. or lower.

  On the other hand, when the temperature is 100 ° C. or lower, members such as an interposer and a chip constituting the workpiece 100 are softened to some extent, but warpage of the workpiece 100 is rarely autonomously corrected, and the workpiece 100 is attracted to the holding table 31. It is not easy to correct the warp of the workpiece 100 with the force of.

  Therefore, in this ball mounting apparatus 1, in step 92 of FIG. 4, the warp correction function 83 is plate-shaped while heating the workpiece 100 mounted on the holding table 31 to the above temperature as shown in FIG. 6. And press against the rigid correction jig 70. Since the workpiece 100 is pressed from above by the correction jig 70, the warp of the workpiece 100 is mechanically corrected. Furthermore, the workpiece 100 can be maintained in a state in which the warpage is corrected by supporting the lower side of the workpiece 100 by the suction mechanism 36 of the holding table 31 while heating the workpiece 100 in which the warpage has been corrected.

  In this ball mounting apparatus 1, the correction jig 70 is disposed on the lower side of the mask 10 so as to face the lower surface 14 of the mask 10 with a slight distance. The correction jig 70 of this example is made of metal such as aluminum, and as shown in FIG. 1, an opening 71 is provided so that the workpiece 100 can be pressurized while avoiding the section 103 where the electrode 102 of the workpiece 100 is disposed. It has been. Therefore, even if the workpiece 100 is pressed by the correction jig 70, the electrode 102 of the workpiece 100 is not damaged, or the shape of the flux previously applied to the electrode 102 is not damaged.

  Next, in step 93 of FIG. 4, the function 84 for confirming the position confirms the position of the workpiece 100 whose warpage has been corrected using the left and right observation cameras 50a and 50b, as shown in FIG. The correction jig 70 is arranged so that the observation windows 77a and 77b coincide with the observation windows 17a and 17b of the mask 10, respectively. In this step 93, the reference marks 105a and 105b are obtained by the cameras 50a and 50b. These images are acquired through the observation windows 17a and 17b of the mask 10 and the observation windows 77a and 77b of the correction jig 70.

  As shown in FIG. 1, the observation cameras 50a and 50b are respectively attached to a base frame 22 integrated with the base 20 via an XYZ table 51, and the upper direction of the mask 10 is in the X direction, Y direction and Z direction. It is arranged to move in the direction. Accordingly, the left and right observation cameras 50a and 50b are moved by the XYZ table 51 to a position where the left and right reference marks 15a and 15b on the mask 10 provided on the mask 10 can be seen from above, and the images of the left and right reference marks 15a and 15b are displayed. Is obtained, the position (relative position or difference in the X and Y directions) and orientation (relative angle or difference in the θ direction) of the mask 10 with respect to the base frame 22 can be confirmed. The position confirmation of the mask 10 may be performed when the mask 10 is attached to the mask holder 21, and may be performed thereafter to confirm the position and orientation of the mask 10 at an appropriate interval.

  In this step 93, as shown in FIG. 6, the left and right observation cameras 50a and 50b are moved to positions where the reference marks 105a and 105b of the workpiece 100 can be seen by the XYZ table 51, that is, the observation windows 17a and 17b of the mask 10. The position of the workpiece 100 relative to the moving stage 30 (relative position or difference in the X and Y directions) and orientation (relative angle or difference in the θ direction) are confirmed. FIG. 6 shows a state in which one reference mark 105a is acquired by the camera 50a through the observation windows 77a and 17a. Since the relationship between the position (movement amount) of the moving stage 30 and the base frame 22 is known in advance, the relationship between the position and direction of the mask 10 and the position and direction of the workpiece 100 is determined by this step 93, and the moving stage. 30, the workpiece 100 can be accurately moved with respect to the mask 10 so as to be in an arbitrary position and orientation.

  Instead of providing the observation windows 77a and 77b on the correction jig 70, when the images of the reference marks 105a and 105b of the workpiece 100 are acquired via the observation windows 17a and 17b of the mask 10, the correction jig 70 is used. May be retracted to a position where it does not interfere with the observation windows 17a and 17b of the mask 10. Further, this step 93 may be performed when the warp of the workpiece 100 is corrected by the correction jig 70, or may be performed in a state where the workpiece 100 is separated from the correction jig 70 after correction. Step 93 is performed each time the new workpiece 100 is transported to the lower side of the mask 10 by the moving stage 30.

  When the position confirmation of the workpiece 100 is completed, the workpiece 100 is moved to the position where the conductive ball B under the opening 12 of the mask 10 is mounted by the function 81 for controlling movement in Step 94 of FIG. The workpiece 100 is aligned. The upper surface 101 of the workpiece 100 is in close contact with the lower surface 14 of the mask 10 or the gap between the upper surface 101 of the workpiece 100 and the lower surface 14 of the mask 10 is such that the conductive ball B does not flow out, for example, from several μm to several tens of μm. Set to be.

  By confirming the position of the workpiece 100 on the lower side of the mask 10, the distance that the workpiece 100 moves between the position confirmation step 93 and the positioning step 94 is shortened. Further, since the same observation cameras 50a and 50b can be used for confirming the position of the work 100 and confirming the position of the mask 10, the position accuracy of the work 100 is improved. In step 94, the position of the work 100 with respect to the mask 10 is determined with higher accuracy. it can. By this method, the alignment error can be reliably reduced to several μm (for example, 5 μm) or less.

  Next, in step 95 of FIG. 4, as shown in FIG. 7, the filling head 5 is moved along the upper surface 11 of the mask 10 by the filling function 85 to fill the opening 12 of the mask 10 with the conductive ball B. To do. The process of filling the conductive balls B (step 95) is performed in a state where the work 100 is sucked and supported on the holding table 31 while the work 100 is heated by the heater 37 of the holding table 31. Further, this process is performed while the mask 10 is cooled by the cooling device 60. In order to manage the temperature in the holding table 31, a temperature sensor such as a thermocouple may be built in, and the temperature of the holding table 31 may be managed by the function 82 for temperature control. By making the heat capacity of the holding table 31 sufficiently larger than the heat capacity of the work 100 or the like, the temperature of the work 100 can be set to an appropriate range regardless of the presence or absence of the work 100 or whether or not the work 100 is in contact with the mask 10. It is also possible to hold it.

  The mask 10 for arranging the conductive balls B has a thickness equal to or smaller than the diameter of the conductive balls B, for example, about 50 μm, and is typically formed using an electrodeposited metal such as a Ni—Co alloy. The ultra-thin mask 10 is adjusted so as to be in close contact with the surface 101 of the workpiece 100 at normal temperature. However, when the workpiece 100 having a higher temperature than the surroundings is in close contact with or close to the workpiece 100, the mask 10 receives heat from the workpiece 100. As the temperature rises, the temperature distribution of the mask 10 may change and deform. In addition, the mask 10 includes a plurality of openings 12 patterned so that the conductive balls B are thrown in. Since the thickness and shape differ depending on the location, there is a possibility that the temperature distribution is generated and the mask 10 is deformed. If the mask 10 is bent or distorted, there is a possibility that a gap for the conductive ball B to enter between the workpiece 100 and the mask 10 may occur even if the warpage of the workpiece 100 is corrected.

  In this ball mounting device 1, the conductive ball B is filled while the mask 10 is cooled by the cooling device 60, thereby suppressing the occurrence of distortion and bending of the mask 10. For this reason, even if it makes the workpiece | work 100 closely_contact | adhere to the mask 10 or heating, it can suppress generation | occurrence | production of the filling mistake called a lost ball or a double ball. A temperature sensor such as a thermocouple may be attached to the mask 10 to control the cooling capacity of the cooling device 60 while monitoring the temperature of the mask 10. The cooling device 60 may start cooling the mask 10 when the work 100 serving as a heat source approaches the mask 10. Alternatively, the temperature controlled by the cooling device 60 may be blown onto the mask 10 so that the temperature of the mask 10 is constantly maintained.

  Further, in this ball mounting device 1, the cooling device 60 cools the mask 10 by blowing cooling air 65 onto the lower surface 14 of the mask 10. In the step of filling the conductive ball B (step 95), the opening 12 of the mask 10 is closed by the work 100. For this reason, even if the air 65 is blown onto the lower surface 14 of the mask 10, the influence of the air 65 on the conductive balls B supplied to the upper surface 11 of the mask 10 can be prevented. Further, the influence of the air 65 on the conductive ball B filled in the opening 12 of the mask 10 can be prevented. Therefore, air 65 having a sufficient air volume for cooling the mask 10 can be supplied from the cooling device 60 to the mask 10. Since the mask 10 is sufficiently thin as described above, the overall temperature increase of the mask 10 can be suppressed by cooling the lower surface 14 of the mask 10, and distortion and deflection caused by partial heating of the mask 10 by the workpiece 100. Can be suppressed.

  The filling head 5 of the ball mounting apparatus 1 is a rotary type as shown in FIG. 3, and the conductive balls B are held in the moving section 18 inside the rotating squeegee 5a. Therefore, it is possible to cool the mask 10 by blowing cooling air 65 onto the upper surface 11 of the mask 10 in addition to or instead of the lower surface 14 of the mask 10. On the other hand, the filling head 5 moves throughout the section 13 provided with the plurality of openings 12 of the mask 10 while holding the conductive balls B. Therefore, the cooling device 60 that supplies the cooling air 65, for example, the fan and / or the duct, is arranged avoiding the moving path of the filling head 5. The configuration in which the cooling device 60 is disposed on the lower side of the mask 10 and the cooling air is supplied to the lower surface 14 of the mask 10 is one of the preferred embodiments because it can prevent interference with the filling head 5 in advance. .

  The conductive balls B filled in the openings 12 of the mask 10 are mounted on the electrodes 102 of the workpiece 100 using the mask 10 as a template. When the workpiece 100 is separated from the mask 10 by the moving stage 30, the conductive balls B are placed on the respective electrodes 102. The workpiece 100 in which the conductive balls B are arranged can be obtained. Therefore, the work 100 in which the conductive balls B are arranged can be manufactured by performing a process such as reflow and fixing the conductive balls B to the work 100.

  As described above, in the ball mounting apparatus 1, the workpiece 100 is heated, and once the warp is corrected by the correction jig 70, the workpiece 100 is sucked and supported by the holding table 31 while being heated. Therefore, the warp of the workpiece 100 can be corrected by heating the workpiece 100 to an appropriate temperature that does not greatly affect the flux or the like, for example, 120 ° C. or less, preferably 100 ° C. or less, and the corrected state can be maintained. Thereafter, the workpiece 100 is aligned with the mask 10 while being heated and supported by the holding table 31, and the conductive ball B is mounted on the workpiece 100 while the mask 10 is cooled. Therefore, the thermal influence on the mask 10 due to the workpiece 100 being heated can be suppressed, and problems due to distortion and deflection of the mask 10 can be prevented in advance. For this reason, it is possible to accurately mount the fine conductive balls B of 100 μm or less even on the workpiece 100 which is relatively likely to be warped, such as a laminated semiconductor, and to manufacture the workpiece 100 with high reliability.

  The ball mounting apparatus 1 supports the workpiece 100 using the holding table 31 that can be moved in the XYZ directions by the moving stage 30 as a moving body. However, the workpiece 100 is masked 10 by a moving system such as a belt conveyor. The apparatus which moves the workpiece | work 100 with the moving body which conveys to the lower side and moves the lower side of the mask 10 may be sufficient. The shape of the moving body is not limited to the plate-like shape shown in FIG. 2, and a concave portion formed so as to receive the workpiece 100 may be used, and the workpiece 100 is loaded / unloaded on the moving body. For example, a belt or a pulley may be provided.

1 ball mounting device,
10 mask, 12 opening 30 moving stage, 31 holding table (moving body)
60 Cooling device, 70 Straightening jig 100 Workpiece

Claims (9)

Mounting a conductive ball on a workpiece through a mask having a plurality of openings for mounting the conductive ball, the method comprising:
The mounting is
A movable body that supports at least the lower surface side of the workpiece, the movable body including a mechanism for heating the workpiece, mounted on the movable body, and moved under a correction jig disposed under the mask. When,
While heating the workpiece mounted on the movable body, pressing at least a part of the workpiece from above with a correction jig to correct the warp of the workpiece;
An observation camera observes the reference mark of the mask from above the mask and observes the reference mark of the work through a window provided in the mask to confirm the position of the work and the mask. And
Positioning the workpiece and the mask mounted on the movable body based on the confirmed positions of the workpiece and the mask;
The plurality of openings of the mask are moved by moving the filling head along the upper surface of the mask while cooling the mask by a cooling device while facing the lower surface of the mask while heating the workpiece by the moving body. Filling each of the with conductive balls. 2. The confirmation according to claim 1, wherein the observation camera observes the reference mark of the workpiece from above the mask through a window provided in the mask and a window provided in the correction jig. And confirming the position of the workpiece and the mask. 3. The method according to claim 2, wherein the confirmation includes the observation camera observing a reference mark of the workpiece in parallel with the correcting. 4. The method according to claim 1, wherein the filling includes blowing air to a lower surface of the mask by the cooling device. 5. The method according to claim 1, wherein the filling includes sucking and supporting the workpiece by the moving body. A mask having a plurality of openings for mounting conductive balls on the workpiece;
A moving body that supports at least the lower surface side of the work and controls the position of the work with respect to the mask, the moving body including a mechanism for heating the work, and facing the lower surface of the mask while the work is heated Body,
A filling head that moves along the top surface of the mask and fills each of the plurality of openings of the mask with conductive balls;
An apparatus for cooling the mask from a position avoiding the movement path of the filling head;
A warp correction jig that pressurizes at least a part of the workpiece mounted on the movable body on the lower side of the mask from above;
A camera for observing the reference mark of the mask from above the mask, and observing the reference mark of the work that has been warped through a window provided in the mask to confirm the position of the work and the mask; Ball mounting device including. 7. The correction jig according to claim 6, wherein the correction jig includes a window for observing a reference mark of the workpiece, and the camera passes through a window provided on the mask and a window provided on the correction jig from above the mask. A ball mounting apparatus that observes a reference mark of the workpiece and confirms a position of the workpiece and the mask. 8. The ball mounting apparatus according to claim 6 , wherein the cooling device includes a fan that blows air toward a lower surface of the mask. 9. The ball mounting device according to claim 6 , wherein the moving body includes a function of sucking and supporting the workpiece.

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