JPH08206824A - Device for mounting solder ball and method therefor - Google Patents

Abstract

PURPOSE: To provide a device for mounting solder balls which can bond the solder ball after sticking uniform quantity of flux on the solder ball, and a method for mounting the solder balls. CONSTITUTION: This device is provided with a squeegee contacting with flux on a flattened part 9, a motor 16 for parallel shifting the squeegee to the flattened part 9 and a first and a second cylinders 19, 20 for adjusting the level at the lower edge of the squeegee by ascending/descending the squeegee. In the case of shifting the squeegee to the direction being apart from a recessed part 10, the level at the lower edge of this squeegee is adjusted to the first level so that the film thickness of the flux on the flattened part 9 becomes the desired thickness. In the case of shifting to the direction approaching the recessed part 10, this level is advanced to the second level having lower part than the first level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder ball mounting apparatus and a solder ball mounting method for coating a solder ball with flux to mount the solder ball on an electrode of a substrate.

[0002]

2. Description of the Related Art Solder balls immersed in flux are bonded to electrodes of a substrate of electronic parts such as BGA (ball grid array) or a single substrate, and then the solder balls are heated to melt and solidify the bumps. (Protruding electrodes) are formed. 6 to 8 are process explanatory views of a conventional solder ball mounting method. Figure 6 (a)
Medium 1 is a case where many solder balls 2 are stocked, 3
Is a suction head which has a plurality of suction holes 3a on its lower surface, sucks the solder balls 2 into the suction holes 3a, and transfers the plurality of solder balls 2 collectively. The solder balls 2 adsorbed from the case 1 are dipped in the flux 5 contained in the container 4 at the bottom thereof, and then mounted on electrodes of a substrate (not shown). Here, the flux 5 in the container 4 is adjusted by the sliding squeegee 6 so as to have a constant film thickness t, and as shown in FIG.

[0003]

However, the solder ball 2 adsorbed by the adsorption port 3a of the adsorption head 3 comes off the adsorption head 3, and the container 4 is removed as shown in FIGS. 6 (b) and 8 (a). It may remain inside. At this time,
As shown in (b), in order to prepare for the next immersion of solder balls, the squeegee 6 is adjusted so that the flux 5 has the above-mentioned film thickness t.
Slide the arrow N1 to leave the remaining solder balls 2
The squeegee 6 moves while dragging, and streaks S are formed along the trajectory of the solder ball 2. On the streaks S, the flux 5 is stripped off by the solder balls 2 and is almost nonexistent. As described above, in the conventional solder ball mounting device, when the solder balls remain in the container, the flux film thickness becomes non-uniform, and the amount of the flux adhering to the solder balls varies and the solder balls used when heating the solder balls later There is a problem that the wetting property of the ball is deteriorated.

Therefore, an object of the present invention is to provide a solder ball mounting apparatus and a solder ball mounting method which are capable of bonding a uniform amount of flux to a solder ball and then bonding the solder ball.

[0005]

A solder ball mounting apparatus of the present invention includes a substrate having an adsorption port for adsorbing a solder ball, an adsorption head for transferring the solder ball, and an electrode on which the solder ball is to be mounted. A positioning part for positioning, a horizontal flat part disposed in the moving path of the suction head, and having a horizontal flat part on which the flux is formed, and a recessed part formed in this flat part, and the flux on the flat part. A squeegee that comes into contact with the squeegee, a moving means that moves the squeegee parallel to the flat portion, and a level adjusting means that raises and lowers the squeegee to adjust the level of the lower edge of the squeegee. When sliding away, adjust the level of the lower edge of this squeegee to the first level so that the flux film thickness on the flat part will be the desired thickness. There When sliding direction toward the recess, adjusting the level of the lower edge of the squeegee to the second level lower than said first level.

[0006]

With the above construction, even if the solder balls remain on the flat portion of the container, the level of the squeegee is first lowered and the squeegee is slid by the moving means to remove the remaining solder balls from the center of the flat portion. At this time, the solder balls may be dragged on the flat portion to form the above-described streaks in the flux, and the film thickness may become uneven. However, next, the level of the lower edge of the squeegee is slightly raised and the squeegee is moved in the opposite direction, so that the flux has a uniform film thickness again on the flat portion having no solder ball. As a result, a flux having a uniform film thickness is formed on the flat portion, the flux is evenly dipped in the plurality of solder balls sucked by the suction head, and the flux is mounted on the substrate.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a perspective view of a solder ball mounting device according to an embodiment of the present invention. In the drawings, the same components as those of FIGS. 6 to 8 showing the conventional solder ball mounting apparatus are designated by the same reference numerals and the description thereof will be omitted.

Reference numeral 7 denotes a BGA substrate which is positioned by the positioning portion P in a state of being turned upside down, and a plurality of electrodes 7a on which the solder balls 2 immersed in the flux 5 are to be mounted one by one are provided above the substrate. Has been. Reference numeral 8 denotes a container having an open upper end, and its bottom has a horizontal flat portion 9. Further, the flat portion 9 is provided at both ends of the flat portion 9 in the longitudinal direction.
The recess 10 having a lower level than that is continuously provided. A flux 5 having a predetermined film thickness is formed on the flat portion 9 by a squeegee described later.

Reference numerals 11 and 12 are guide rails provided on both sides of the container 8 in the longitudinal direction, and 13 is guide rails 11 and 12.
A moving plate fixed on the slider 14 slidably engaged with the moving plate 13, 19 is a first cylinder serving as a first elevating means fixed to the moving plate 13, and a flat portion 9 is formed on the lower end of the rod 19a. First squeegee 2 in contact with flux 5
1 is fixed. Further, as shown in FIG. 2, a second cylinder 20 as a second elevating means is fixed to the back side of the first cylinder 19 of the moving plate 13 in parallel with the first cylinder 19 with a space therebetween. The second squeegee 22 is fixed to the rod 20a.

Here, in this embodiment, the first cylinder 19
The lifting strokes of the rod 19a of the second cylinder 20 and the rod 20a of the second cylinder 20 are exactly the same.
The height h1 of the second squeegee 22 and the height h0 of the second squeegee 22 are determined as follows. That is, the first film thickness of the flux 5 formed on the flat portion 9 is t1, and the second film thickness thereof is t0 (t0 <t1).
And the height from the flat portion 9 to the lower surface of the moving plate 13 is H,
If the maximum length of the rods 19a and 20a is L, h1 =
HL-t1, h0 = HL-t0. That is,
As shown in FIG. 2, when the rod 20a of the second cylinder 20 is projected and the rod 19a of the first cylinder 19 is retracted, the lower edge of the second squeegee 22 is above the flat portion 9 by the second film thickness t0. When the moving plate 13 is located at the second level and is moved leftward in this state, the second film thickness t0 is formed on the flat portion 9.
The flux 5 will be molded. Further, as shown in FIG. 3, when the rod 20a is retracted and the rod 19a is projected, the lower edge of the first squeegee 21 moves from the flat portion 9 to the first portion.
The flux 5 having the first film thickness t1 (t0 <t1) is formed on the flat part 9 when the moving plate 13 is moved to the right at the first level which is located above the film thickness t1. become. In this embodiment, the first cylinder 19 and the second cylinder 20 correspond to the level adjusting means. Of course, the rod 19
The lifting strokes of a and 20a may be different by the difference between the first level and the second level.
The lower edge of No. 1 is lowered to the first level by the first cylinder 19, and the lower edge of the second squeegee 22 is moved to the second cylinder 20.
You may make it descend | fall to a 2nd level by. The first film thickness t1 is predetermined so as to be convenient for attaching the flux 5 to the lower portion of the solder ball 2. The second film thickness t0 is preferably about 0.1 to 0.4 times the diameter of the solder ball 2.
The film thickness t may be almost zero by moving the second squeegee 22 while pressing it against the flat portion 9.

Next, the moving means will be described. In FIG. 1, 15 is a feed screw that is rotatably supported laterally in the longitudinal direction of the container 8, 16 is a motor that rotates the feed screw 15, 17 is screwed with the feed screw 15, and the upper portion is the bracket 1
8 is a feed nut connected to the moving plate 13. Therefore, when the motor 16 is driven, the moving plate 13
At the same time, the first squeegee 21 and the second squeegee 22 can be moved in the longitudinal direction of the container 8.

Next, the operation of the solder ball mounting device of this embodiment will be described with reference to FIGS. First, moving plate 1
3 is moved along the outward path. That is, as shown by the solid line in FIG. 2, the rod 19a of the first cylinder 19 is immersed,
The rod 20a of the second cylinder 20 is projected to position the lower edge of the second squeegee 22 above the flat portion 9 by the second film thickness t0, and the motor 16 is driven to move the second squeegee 22 together with the moving plate 13. Move in the direction of arrow N2. here,
Since the second film thickness t0 is smaller than the diameter of the solder ball 2,
When the solder ball 2 remains on the flat portion 9, the second squeegee 22 moves in the direction of the arrow N2,
When the solder ball 2 remaining on the flat portion 9 together with the flux 5 is attracted and the second squeegee 22 passes above the recessed portion 10, the solder ball 2 is dropped into the recessed portion 10 from above the flat portion 9. The solder balls 2 are removed (see the chain line in FIG. 2).

Next, the moving plate 13 is moved along the return path opposite to the above-mentioned forward path. That is, as shown in FIG. 3, the rod 20 a of the second cylinder 20 is retracted, and the first cylinder 19
By projecting the rod 19a of the above, the level of the lower edge of the first squeegee 21 is made higher than the flat portion 9 by the first film thickness t1. Next, the motor 16 is driven to move the first squeegee 21 in the direction of arrow N3 together with the moving plate 13. As a result, a uniform film of the flux 5 having the first film thickness t1 is formed on the flat portion 9. Here, when the solder ball 2 remains on the outward path, the second film thickness t
A streak may be formed in the film of the flux 5 of 0 along the trajectory of the solder ball 2, but since the first film thickness t1 is thicker than the second film thickness t0, this second squeegee 22 When moving along the return path (arrow N3), the streaks disappear due to the flux 5 filling the streaks, and the first film thickness t
A film of uniform thickness of 1 is formed on the flat portion 9.
The first film thickness t1 is thicker than the second film thickness t0, that is, the level at which the first squeegee 21 scrapes the flux 5 is higher than the level at which the second squeegee 22 scrapes the flux 5. When the first squeegee 21 moves on the return path, the solder ball 2 once dropped in the recess 10 does not come out of the recess 10 again and return to the flat part 9.

Next, as shown by an arrow N4 in FIGS. 4 and 1, a plurality of solder balls 2 are picked up by a suction head 3 from a case 1 of the solder balls 2, and a flux 5 having a first film thickness t1 is spread. The lower portion of the solder ball 2 is immersed in the flat portion 9 and the flux 5 is attached to the lower portion of the solder ball 2. Then, as shown by an arrow N5 in FIGS. 5 and 1,
By moving the suction head 3, the solder balls 2 to which the flux 5 is attached are mounted on the electrodes 7a of the substrate 7.

Here, in this embodiment, the first squeegee is used.
A squeegee 21 and a second squeegee 22 were prepared separately from each other, and the lower edge level when using each squeegee was set to be different, but using a single squeegee, the lower edge of this squeegee on the outward path was The level may be set from the flat portion 9 to the second film thickness t0 (that is, lower), and the same level in the return path may be set from the flat portion 9 to the first film thickness t1 (that is, higher).

[0017]

According to the solder ball mounting apparatus of the present invention, the squeegee which contacts the flux on the flat portion, the moving means for moving the squeegee parallel to the flat portion, and the level of the lower edge of the squeegee for raising and lowering the squeegee. By including a level adjusting means for changing the film thickness of the flux on the flat portion by adjusting the above, even amount of flux is adhered to the solder ball even if the solder ball falls and remains on the flat portion. Therefore, the wetting property of the solder ball can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a solder ball mounting device according to an embodiment of the present invention.

FIG. 2 is a process explanatory diagram of a solder ball mounting method according to an embodiment of the present invention.

FIG. 3 is a process explanatory diagram of a solder ball mounting method according to an embodiment of the present invention.

FIG. 4 is a process explanatory diagram of a solder ball mounting method according to an embodiment of the present invention.

FIG. 5 is a process explanatory diagram of a solder ball mounting method according to an embodiment of the present invention.

6A is a process explanatory diagram of a conventional solder ball mounting method. FIG. 6B is a process explanatory diagram of a conventional solder ball mounting method.

FIG. 7 is a process explanatory diagram of a conventional solder ball mounting method.

8A is a process explanatory view of a conventional solder ball mounting method. FIG. 8B is a process explanatory view of a conventional solder ball mounting method.

[Explanation of symbols]

 2 Solder ball 3 Suction head 3a Suction port 5 Flux 7 Substrate 7a Electrode 8 Container 9 Flat part 19 First cylinder 20 Second cylinder 21 First squeegee 22 Second squeegee P Positioning part

Claims (11)

[Claims] 1. A suction head which has a suction port for sucking a solder ball and which transfers the solder ball, and a positioning portion which positions a substrate having an electrode on which the solder ball is to be mounted,
A squeegee which is disposed in the moving path of the suction head and has a horizontal flat portion on which the flux is formed and a container having a recess formed in the flat portion, and which comes into contact with the flux on the flat portion. And a moving means for moving the squeegee parallel to the flat portion, and a level adjusting means for moving the squeegee up and down to adjust the level of the lower edge of the squeegee. When sliding in the direction away from the concave portion, the level of the lower edge of this squeegee is adjusted to the first level so that the film thickness of the flux on the flat portion becomes a desired thickness,
When the squeegee slides toward the recess, the level of the lower edge of the squeegee is adjusted to a second level lower than the first level. 2. A suction head for sucking a solder ball, a suction head for transferring the solder ball, and a positioning portion for positioning a substrate having an electrode on which the solder ball is to be mounted,
A container is provided in the moving path of the suction head, and has a horizontal flat portion on which flux is formed and a container having a recess formed in the flat portion, and is supported so as to be horizontally movable in parallel with the container. A moving plate, a moving means for horizontally moving the moving plate, a first squeegee and a second squeegee supported to be movable up and down with respect to the moving plate, and the moving plate, wherein the first squeegee is provided. First elevating means for lowering the lower edge of the first squeegee to a first level when moving away from the recess, and the moving plate, and the second elevating means.
A solder ball mounting device including second elevating means for lowering a lower edge of the second squeegee to a second level lower than the first level when the squeegee approaches the recess. . 3. The first squeegee and the second squeegee differ in vertical length by the difference between the first level and the second level, and the first lifting means and the second lifting means. Is the first squeegee and the second with respect to the moving plate.
3. The solder ball mounting device according to claim 2, wherein the squeegee is lowered with the same stroke. 4. The first squeegee and the second squeegee have the same vertical length, and the first elevating means and the second squeegee.
3. The solder ball mounting device according to claim 2, wherein the elevating means descends and descends with respect to the moving plate by strokes different from each other by a difference between the first level and the second level. 5. The solder ball mounting device according to claim 2, wherein a gap between the second level and the flat portion is smaller than a diameter of the solder ball. 6. A flux is stored in a container provided with a flat portion and a recess formed in the flat portion, a squeegee is slid on the flat portion, and the flux on the flat portion is drawn to the recess side. Step, and while adjusting the level of the lower edge of the squeegee to the first level, by sliding the squeegee on the flat portion in the direction away from the recess, the flux is formed on the flat portion with a desired film thickness. Forming step, immersing the lower part of the solder ball adsorbed by the adsorption head in the formed flux to attach the flux to the lower part of this solder ball, and attaching the flux-attached solder ball to the substrate electrode And a step of mounting the solder ball on the solder ball. 7. The solder ball existing on the flat portion is scraped together with the flux when the flux on the flat portion is scraped toward the recessed portion, and is dropped into the recessed portion. Solder ball mounting method. 8. When scraping the flux on the flat portion toward the concave portion, the level of the lower edge of the squeegee is set to the first level.
7. The solder ball mounting method according to claim 6, wherein the solder ball is lowered to a second level lower than the level. 9. The solder ball mounting method according to claim 6, wherein the squeegee is a single squeegee. 10. The solder ball mounting method according to claim 6, wherein the squeegee is a separate one from a first squeegee for flux forming and a second squeegee for flux scraping. 11. The solder ball mounting method according to claim 6, wherein a gap between the second level and the flat portion is smaller than a diameter of the solder ball.