JP4899125B2 - Method and apparatus for mounting conductive ball - Google Patents

Description

  The present invention relates to a method and an apparatus for mounting a conductive ball on a mounting location of a mounting object using an array mask provided with a through hole in accordance with a mounting location formed in a predetermined pattern on the mounting object. Is.

  Patent Document 1 discloses an apparatus and method for mounting a conductive ball on a mounting position of a mounting object using an array mask provided with a through hole in accordance with a mounting position formed in a predetermined pattern on the mounting object. As shown in FIG. 2, there has been an apparatus and a method for arranging conductive balls by moving a ball reservoir containing a large number of conductive balls on an arrangement jig.

  However, in the dropping method by the movement of the ball cup adopted in the mounting method and mounting device of the conductive ball described in Patent Document 1, the conductive ball is inevitably caught between the ball cup and the array mask. It was a thing. In addition, the smaller the diameter of the conductive ball, the higher the accuracy required for the gap between the ball cup and the arrangement mask, the flatness of the arrangement mask, the horizontal movement of the ball cup, and the like. There was also a risk that the conductive balls leaked out and could not be dropped.

  Therefore, in order to prevent the occurrence of the biting of the conductive balls, as shown in Patent Document 2, the ball assembly in the ball cup is caused by the air flow during the horizontal movement of the ball cup (cylindrical member in Patent Document 2). An apparatus and method have been provided to prevent the ball from contacting the ball cup.

  However, since the ball cup must be moved so that the aggregate of conductive balls does not come into contact with the ball cup, the movement speed of the ball cup cannot be made very high, and this increases the time required for the mounting process. There was a problem. Another possible method is to increase the airflow flowing between the arrangement mask and the ball cup, but if the inflow airflow speed is increased, the conductive balls do not collect on the arrangement mask and soar in the ball cup. In some cases, mounting failure occurred.

Japanese Patent Laid-Open No. 2006-318994 Japanese Patent Laid-Open No. 2006-73999

  The present invention drops a conductive ball into a through hole of an array mask and mounts the conductive ball on a mounted object by adsorbing the conductive ball to a ball adsorber existing above the array mask. It is an object of the present invention to prevent the conductive balls from being caught between these and the arrangement mask by the movement. This increases the moving speed of the ball cup that supplies the conductive balls, thereby contributing to the improvement of productivity.

In order to solve the above problems, the present invention mounts conductive balls on a mounted object using an array mask provided with through holes in accordance with mounting positions formed in a predetermined pattern on the mounted object. The following means is adopted for the mounting method and mounting device of the conductive balls to be mounted at the locations.
First, a mask holding means for holding the array mask on the mounted object, a ball cup having a space inside and a lower end surface being an opening, and provided in the ball cup and provided above the array mask A ball adsorber that is connected to a vacuum source and can adsorb a conductive ball on its lower surface, a vacuum switching means for switching ON / OFF of the suction state of the ball adsorber by the vacuum source , and a ball cup on the upper surface of the array mask And a moving unit that is movable along .
Second, the vacuum switching means turns on the suction state of the ball adsorber and allows the gas to flow in from the gas flow path formed between the ball cup and the array mask , so that the conductivity existing below the ball adsorber is present. and the adsorption step and the adsorption behavior Ru is adsorbed to the ball adsorbent balls, and the movement step and the moving operation moving the ball cup in a predetermined mounting position, and the suction state of the ball adsorber OFF at the predetermined mounting position The conductive ball adsorbed on the ball adsorber is dropped, and the conductive ball is formed on the mounted object by repeating the mounting process and mounting operation for mounting the conductive ball on the mounted object a plurality of times. A conductive ball is mounted on the mounting location.

  In the present invention, after the suction state of the ball adsorber is turned on by the vacuum switching means and the conductive ball existing below the ball adsorber is adsorbed to the ball adsorber, the ball adsorber is turned off and the ball adsorber is turned off. Since the conductive ball is mounted by dropping the conductive ball that has been adsorbed on the adsorbent, the conductive ball is caught between the ball adsorber and its attached ball cup and the array mask. Can be prevented from occurring. As a result, it was possible to increase the moving speed of the ball adsorber and the ball cup and improve productivity.

  Hereinafter, embodiments of the present invention will be described together with examples according to the drawings. In the present invention, the conductive ball mounting object includes a semiconductor wafer (hereinafter simply referred to as a wafer), an electronic circuit board, a ceramic substrate, and the like, and an electrode is formed as the conductive ball mounting position. ing. In the embodiment, a solder ball mounter is used in which the conductive ball is the solder ball 1 and the mounted object is the wafer 2.

  The solder ball mounter generally has a wafer transfer section for loading, a flux printing section, a ball mounting section, and a wafer transfer section for unloading. The mounting method and mounting apparatus for conductive balls according to the present invention are as follows. This relates to the ball mounting portion.

  In the ball mounting portion of the first embodiment, the solder ball supply device 4, the ball arrangement mask 3 in which the through holes 31 arranged in accordance with the pattern of the electrodes on the wafer 2 are formed, and the solder balls 1 are passed through the through holes. There are a ball cup 5 and a drive mechanism for the ball cup 5 for dropping into the ball 31.

  In the embodiment, the thickness of the ball arrangement mask 3 is substantially the same as the diameter of the solder ball 1 to be supplied, and the diameter of the through hole 31 is slightly larger than the diameter of the solder ball. However, the through hole 31 has a lower opening diameter larger than the upper opening diameter so that the flux printed on the wafer 2 does not adhere to the ball array mask 3. Instead of increasing the opening diameter, a flux adhesion preventing gap may be provided between the ball array mask 3 and the wafer 2. The ball array mask 3 is attached to the mold 33 and held by a fixed part such as a frame.

  The ball cup 5 has a space inside, a lower end surface is an opening 51, and the internal space is partitioned into an upper space 53 and a lower space 54 by a ball adsorber 52. For this reason, the upper part of the ball cup 5 from the mounting position of the ball adsorber 52 is the casing of the ball adsorber 52. The ball adsorbent 52 is made of a metal mesh such as a stainless mesh that allows the gas to pass therethrough without allowing the solder ball 1 to pass through. In the illustrated embodiment, the ball cup 5 has a single rectangular shape, but the number, shape, and size thereof are determined in consideration of the shape and mounting efficiency of the wafer 2 that is to be mounted. For example, the lower end opening 51 may be circular, or a plurality of ball cups 5 including the ball adsorbers 52 may be provided.

The upper space 53 of the ball cup 5 is connected to a vacuum source 59 by a suction passage 55 via an electromagnetic on-off valve 57 serving as a vacuum switching means and a regulator 58 capable of adjusting the pressure and flow rate of the gas. A gas flow passage as shown by an arrow in FIG. In addition, by opening the electromagnetic on-off valve 57 as a vacuum switching means for switching ON / OFF of the suction state in the ball cup 5 by the vacuum source, the suction state in the ball cup 5 is turned ON and exists below the ball cup 5. After the solder ball 1 is adsorbed to the ball adsorber 52, the attracting state in the ball cup 5 is turned off by closing the electromagnetic on-off valve 57, and the solder ball 1 adsorbed to the ball adsorber 52 is dropped. The solder balls 1 are mounted on the wafer 2.
The ball cup 5 and the ball adsorber 52 are made of a conductive material and are grounded by a ground 60 as shown in FIGS. This prevents the electrostatically charged solder ball 1 from adhering to the inner surface of the ball cup 5 or the ball adsorbent 52. Further, a vibrator 61 for applying minute vibrations to the ball cup 5 is attached to the outside of the ball cup 5. The vibrator 61 vibrates at least when the suction state in the ball cup 5 is OFF and is attached to the ball cup 5. Vibration is transmitted to the ball adsorbing body 52, and the falling of the solder ball 1 is promoted.

  The solder ball supply device 4 supplies a large number of solder balls 1 from the ball hopper storing the solder balls 1 to the ball cup 5 through the ball supply path 56. The ball hopper is replaced depending on the size and material of the solder ball 1.

  The ball cup 5 moves in the X-axis direction and the Y-axis direction to cover the entire surface of the wafer 2. As shown in FIG. 1, the moving unit 10 serving as a moving means of the ball cup 5 on the horizontal plane includes an X-axis drive mechanism and a Y-axis drive mechanism. It moves along the X-axis guide 11 in the X-axis direction, and moves along the Y-axis guide 12 along the Y-axis direction by the ball screw 16 rotated by the Y-axis drive motor 15 together with the X-axis drive mechanism.

  The elevating device 18 for the ball cup 5 is configured such that an elevating base on which the ball cup 5 is mounted is attached to a ball screw rotated by a Z-axis drive motor 17 provided in the moving unit 10 via a nut member. Moves up and down along the guide rail to move the ball cup 5 up and down. Note that the lower end of the ball cup 5 and the upper surface of the ball array mask 3 may be larger than the diameter of the solder ball 1 as long as a predetermined gas flow can be obtained during the ball suction operation. The solder ball supply device 4 moves integrally with the ball cup 5 and supplies the solder ball 1 into the ball cup 5, but may be provided separately from the ball cup 5, and The solder balls 1 are temporarily supplied onto the ball arrangement mask 3 outside the cup 5 and the solder balls 1 are supplied to the mounting position by moving the ball cup 5 while adsorbing the solder balls 1 by the ball adsorber 52. Is also possible.

  The operation of the first embodiment will be described below. First, as a pre-process for transferring the wafer 2 to the ball mounting portion, the flux is applied to the ball mounting portion on the wafer 2 in advance by the flux printing unit.

  When the wafer 2 is transferred to the ball mounting portion, as shown in FIGS. 2 and 3, the wafer 2 is mounted on the wafer mounting stage 6, and the ball arrangement mask 3 is disposed on the wafer 2. In the embodiment, the flux is prevented from adhering to the ball arrangement mask 3 due to the shape of the through-hole 31 of the ball arrangement mask 3, so that the ball arrangement mask 3 and the wafer 2 are in contact with each other. When it is going to go in the gap between, both do not touch.

  Next, after opening the electromagnetic on-off valve 57 as a vacuum switching means to turn on the suction state in the ball cup 5, the ball cup 5 is moved to the first mounting position by the moving unit 10. When the suction state in the ball cup 5 is turned ON, a gas flow path indicated by an arrow in FIG. 2 is formed between the ball cup 5 and the ball arrangement mask 3. Due to this suction force, the solder ball 1 existing below the ball cup 5 floats and is attracted to the ball adsorber 52. This state is a state in which the ball cup 5 is movable. When the suction state is OFF, the ball cup 5 is not moved.

After the ball cup 5 has moved to the initial mounting position, the electromagnetic on-off valve 57 is closed to turn off the suction state in the ball cup 5 and vibrate the vibrator 61. When the suction is stopped, the ball cup 5 is released to the atmosphere, so that the solder balls 1 attached to the ball adsorbent 52 are dropped as shown in FIG. Mounted on. In order to ensure that the solder ball 1 is dropped into the through-hole 31, that is, mounted on the wafer 2, the suction state is repeatedly turned ON (suction) and OFF (stop) several times, and the vibrator 61 opens and closes the electromagnetic on-off valve 57. Repeatedly stop and generate vibration according to.
Since the ball adsorber 52 is disposed above the ball arrangement mask 3, the adsorbed solder ball 1 has potential energy, and comes into close contact with the electrode when the solder ball 1 falls on the flux. It will be.

  After the mounting is completed, the suction state in the ball cup 5 is turned ON by the vacuum switching means, and suction is performed again. The solder balls 1 mounted on the wafer 2 do not rise due to contact with the flux and generate adhesive force, and all the solder balls 1 not in contact with the flux are sucked up, floated, and adsorbed on the ball adsorber 52. become. In this state, the ball cup 5 moves to the next mounting position. The movement to the next mounting position may be started simultaneously with turning on the suction state of the ball cup 5.

  When the mounting operation at the final mounting position is completed, the solder balls 1 leaking from the ball cup 5 and scattered on the ball arrangement mask 3 are collected. Specifically, the sucked ball cup 5 is moved along the upper surface of the ball array mask 3. Although it can collect | recover easily by this, you may provide a special suction collection means.

  In the first embodiment, when the suction state of the ball adsorber 52 is turned off, the air is released to the atmosphere, and the solder ball 1 is dropped by the vibration of the vibrator 61. The solder ball 1 may be forcibly dropped by applying pressure through the passage 55.

  The lower end surface of the opening 51 of the ball cup 5 in the first embodiment is formed in a planar shape parallel to the ball arrangement mask 3, and the lower end surface of the ball cup 5 and the upper surface of the ball arrangement mask 3 are The ball cup 5 is disposed at a position where a gap is formed so that a predetermined gas flow can be obtained during the adsorption operation. In the second embodiment shown in FIG. 4, the lower end surface of the opening 51 of the ball cup 5 is provided. In addition, a slit 62 is formed so that a gas flow can be obtained. The slits 62 are preferably formed radially in the opening 51 or formed in a spiral shape having directionality in one direction. By forming the slit 62, the flow of the gas flow in the gap between the ball cup 5 and the ball array mask 3 can be controlled, and the ball array mask 3 can be prevented from rising. Of course, the opening 51 of the ball cup 5 can be brought into contact with the ball arrangement mask 3 depending on the size of the slit 62.

  Further, in order to limit the range of the drop of the solder ball 1 from the ball adsorber 52 onto the ball arrangement mask 3, as shown in the third embodiment shown in FIG. 5, below the ball adsorber 52 of the ball cup 5, A ball guide 63 having a wide opening at the top and a narrow opening at the bottom according to the mounting range, or by changing the shape in the ball cup 5 as in the fourth embodiment shown in FIG. It is conceivable to make 52 smaller in accordance with the mounting range.

  Further, as a fifth embodiment, as shown in FIG. 7, a gas supply cup 64 covering the ball cup 5 is provided in connection with the gas supply path 65, and a gas such as air or nitrogen is supplied from the gas supply path 65. For example, if nitrogen is supplied, the effect of preventing the solder ball 1 from being oxidized can be obtained. The gas supply from the gas supply path 65 is controlled so that the supply is turned on when the suction state of the ball adsorber 52 is ON, and the supply is turned off when the suction state of the ball adsorber 52 is OFF. Is done. In FIG. 7, a pipe that passes through the center of the ball cup 5 and the gas supply cup 64 is a ball supply path 56 of the solder ball 1.

  Further, the first to fifth embodiments are provided with the ball cup 5, but the lower portion may be eliminated depending on the mounting position of the ball adsorber 52 of the ball cup 5 as shown in FIGS. . That is, instead of the ball cup 5, the ball adsorber 52 is provided at the lower end of the casing 66, and the suction passage 55 is connected to the casing 66, so that the solder ball 1 can be adsorbed by the ball adsorber 52. In the sixth embodiment shown in FIG. 8, a ball supply path 56 is connected through the ball adsorber 52, and the solder balls 1 are supplied onto the ball array mask 3 below the ball adsorber 52. In the sixth embodiment that does not have the ball cup 5, the position of the ball adsorber 52 is set to a lower position compared to the other embodiments.

  In the seventh embodiment shown in FIG. 9, a ball supply cup 67 that covers the ball adsorber 52 and is connected to the ball supply path 56 is provided. The ball supply cup 67 has a function of preventing scattering together with the supply of the solder balls 1. In addition, the code | symbol 68 in FIG. 9 is an raising / lowering apparatus for moving the ball | bowl adsorption body 52 up and down, and the air cylinder is used in 7th Example. The ball adsorbing body 52 is positioned below the ball arrangement mask 3 when the ball is adsorbed, and is raised above the ball arrangement mask 3 so as to give potential energy to the solder balls 1 when the ball is dropped.

Top view explanatory drawing which shows the whole ball mounting part concerning 1st Example. Explanatory drawing of the ball cup of the state which adsorb | sucked the conductive ball in 1st Example Explanatory drawing of the ball cup which shows the state in the middle of the fall of the conductive ball in 1st Example Explanatory drawing which shows the ball cup in 2nd Example. Explanatory drawing which shows the ball cup in 3rd Example. Explanatory drawing which shows the ball cup in 4th Example. Explanatory drawing which shows the relationship between the ball cup and gas supply cup in 5th Example. Explanatory drawing of the ball adsorber in the sixth embodiment Explanatory drawing of the ball | bowl adsorption body with a ball supply cup in 7th Example

Explanation of symbols

1. . . . . . Solder balls . . . . . Wafer 3. . . . . . 3. Ball array mask . . . . . 4. Solder ball supply device . . . . . Ball cup 6. . . . . . Wafer mounting stage 10. . . . . Mobile unit 11. . . . . X-axis guide 12. . . . . Y-axis guide 13, 15, 17. . . . . Drive motor 14,16. . . . . Ball screw 18. . . . . Lifting device 31. . . . . . Through hole 33. . . . . Formwork 51. . . . . Opening 52. . . . . Ball adsorbent 53. . . . . Upper space 54. . . . . Lower space 55. . . . . Suction passage 56. . . . . Ball supply path 57. . . . . Electromagnetic on-off valve 58. . . . . Regulator 59. . . . . Vacuum source 60. . . . . Earth 61. . . . . Vibrator 62. . . . . Slit 63. . . . . Ball guide 64. . . . . Gas supply cup 65. . . . . Gas supply path 66. . . . . Casing 67. . . . . Ball supply cup 68. . . . . lift device

Claims (6)

In the mounting method of the conductive ball, the conductive ball is mounted on the mounting position of the mounting object by using the arrangement mask in which the through hole is provided in accordance with the mounting position formed in a predetermined pattern on the mounting object. ,
Mask holding means for holding the array mask on the mounted object;
A ball cup whose inside is space and whose lower end surface is an opening,
A ball adsorber provided in a ball cup, provided above the arrangement mask, connected to a vacuum source and capable of adsorbing conductive balls on the lower surface;
A vacuum switching means for switching ON and OFF of the suction state of the ball adsorber by a vacuum source ;
A moving unit that allows the ball cup to move along the upper surface of the array mask ,
With the vacuum switching means, the suction state of the ball adsorber is turned ON and the conductive ball existing under the ball adsorber is adsorbed to the ball by injecting gas from the gas flow path formed between the ball cup and the array mask. and the adsorption step of Ru adsorbed on the body, said a moving step of the ball cup is moved to a predetermined mounting position, the predetermined conductivity was adsorbed suction state by the OFF to the ball adsorbent ball adsorber at the mounting position The conductive ball is mounted on the mounting location formed on the mounted object by repeating the mounting process of mounting the conductive ball on the mounted object by dropping the ball a plurality of times. Mounting method of conductive balls. 2. The method of mounting a conductive ball according to claim 1, wherein in the mounting step, the suction state of the ball adsorber is turned on and off a plurality of times. In a conductive ball mounting apparatus for mounting a conductive ball on a mounting position of a mounting object using an array mask provided with a through hole in accordance with a mounting position formed in a predetermined pattern on the mounting object. ,
Mask holding means for holding the array mask on the mounted object;
A ball cup whose inside is space and whose lower end surface is an opening,
Provided in the ball cup, and a ball adsorbent which can adsorb a conductive ball down surface is connected to a vacuum source provided above the array mask,
A vacuum switching means for switching ON and OFF of the suction state of the ball adsorber by a vacuum source ;
A moving unit that allows the ball cup to move along the upper surface of the array mask ,
With the vacuum switching means, the suction state of the ball adsorber is turned ON and the conductive ball existing under the ball adsorber is adsorbed to the ball by injecting gas from the gas flow path formed between the ball cup and the array mask. a suction operation Ru adsorbed on the body, said a moving operation of the ball cup is moved to a predetermined mounting position, the predetermined conductivity was adsorbed suction state by the OFF to the ball adsorbent ball adsorber at the mounting position The conductive ball is mounted on the mounting portion formed on the mounted object by dropping the ball and repeating the mounting operation of mounting the conductive ball on the mounted object a plurality of times. Conductive ball mounting device. 4. The conductive ball mounting apparatus according to claim 3, wherein the ball cup is made of a conductive material and is grounded . 5. The conductive ball mounting device according to claim 3, wherein in the mounting operation, the vacuum switching unit repeats ON / OFF of the suction state of the ball adsorber a plurality of times. The conductive ball mounting apparatus according to claim 3, further comprising a vibration unit configured to vibrate the ball adsorbent.

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