JP2746286B2 - Solder ball transfer jig - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a structure of a jig for transferring a solder ball when forming a solder bump.

[0002]

2. Description of the Related Art As a conventional method for forming solder bumps on a substrate pad, there is a method disclosed in Japanese Patent Application Laid-Open No. 4-65130 shown in FIG.

[0003] The outline is as follows. The solder ball carrier 14 is provided in a vacuum chamber (decompression chamber) 16.
Is covered with a mask 20, a mesh plate 19 and an intake plate 18. A mask 20 made of a metal plate such as stainless steel thinner than the diameter of the solder ball 9 is provided with a light transmitting member 21 to which the solder ball 9 is fitted. The mesh plate 19 made of a stainless wire or the like is a mesh in which a plurality of meshes are exposed in the through holes 21. An intake plate 18 made of a metal plate such as stainless steel is provided with an intake hole 17 facing the through hole 21 with a mesh 19 interposed therebetween.

[0004] With the upper and lower positions of the solder ball carrier 14 and the solder ball container (not shown) in the state of FIG.
The solder ball 9 is fitted into the through hole 21 by vibrating the solder ball carrier 14 and the solder ball container.

When the vacuum device connected to the suction base 15 is driven to reduce the pressure in the vacuum chamber 16, the solder balls 9 fitted into the through holes 21 are formed by the suction force passing through the suction holes 17 and the mesh plate 19. 21.

When the upper and lower positions of the solder ball carrier 14 and the solder ball container are again returned to the state shown in FIG. 4, excess solder balls 9 are dropped, and only the necessary solder balls 9 are placed in the through holes 21. leave. Next, after alignment with the substrate pad portion to which the flux has been applied, the solder ball 9 is brought into contact, and the solder ball 9 is transferred using the adhesiveness. Thereafter, reflow is performed to form solder bumps on the substrate pads.

As another method, as shown in FIG. 5, a solder ball 9 is put into a non-through hole 22 provided in a solder ball transfer mask 1, and a flux 12
After positioning the substrate 10 coated with
There is a method of transferring the solder ball 9 using the adhesiveness of the flux 12.

[0008]

Problems to be Solved by the Invention
In the method of supplying a solder ball to a substrate pad using a solder ball carrier as disclosed in Japanese Unexamined Patent Publication, air leakage occurs due to variation in the diameter of the solder ball and variation in the hole diameter, so that the fixing force of the solder ball is weakened. There is a drawback that when solder is reversed, the solder ball falls and the solder ball cannot be supplied to the substrate pad.

When the fixed solder ball as shown in FIG. 5 is transferred to the board pad, the flux on the board pad is changed due to the variation of the solder ball diameter and the depth of the non-through hole of the solder ball transfer mask. However, there is a drawback that the solder balls cannot be transferred to the substrate pad, and the solder ball cannot be supplied to the substrate pad, because the solder balls do not contact with each other or the solder ball cuts into the corner of the non-through hole.

Further, there is a method in which the solder ball transfer jig and the substrate are turned over at the same time to drop the solder balls on the substrate pads, or a gap is formed between the solder ball transfer mask and the substrate due to the warpage of the substrate. However, there is a drawback that the position shifts and the position shifts.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a solder ball transfer jig, and applies a plate from below vertically to an elastic body inserted into a hole of a mask and a disk placed above the elastic body. The projections provided push up the elastic body and the disk, so that the elastic body and the disk move vertically with respect to the side surface of the hole, hit the substrate set on the top of the jig, and apply the flux to the substrate. Touch the pad. At this time, there are places where the board and the solder ball transfer jig are not in contact with the board pad due to warpage of the solder ball and variations in the diameter of the solder ball. However, as shown in FIG. Elastic body is crushed and deformed in the lateral direction. By applying a force for contacting all the solder balls, all the solder balls are securely brought into contact with the substrate pad and can be transferred to the substrate pad. An elastic body drop prevention projection is provided at the bottom of the hole of the mask.

[0012]

Next, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a view showing a sectional structure of a solder ball transfer jig according to an embodiment of the present invention. In the present embodiment, a hole 6 is provided in the solder ball transfer mask 1, the elastic body 5 is contained therein, and the disk 4 is further mounted thereon. The disk 4 has a concave surface at the center. The solder ball transfer mask 1 uses a metal plate having a thickness of 1 mm or more to suppress warpage.

In order to supply the solder balls 9 to the solder ball transfer jig, about ten times as many solder balls as the number of solder bumps to be formed are placed on the solder ball transfer mask 1, and then the rocking and vibration are applied. Add. The solder balls 9 are prevented from leaking out of the solder ball transfer mask 1 due to the frame 8 provided at the end of the solder ball transfer mask 1 during swinging or vibration. The swing is performed five times or more at a speed of about once a second in the long axis direction of the solder ball transfer jig, and at the same time, the vibration is applied in the short direction of the solder ball transfer mask 1 at 300 Hz to 500 Hz. With this frequency, the elastic body 5 and the disk 4 do not jump out of the hole 6. Solder ball transfer mask 1
The diameter of the hole 6 provided on the solder ball 9 is 140 μm.
The depth of the hole 6 is 70 μm to 100 μm larger than the radius of the solder ball. For example, when the diameter of the solder ball to be used is 800 μm, the diameter of the hole is 940 μm to 1000 μm, and the depth of the hole is 470 μm to 500 μm. By doing so, one solder ball 9 always enters the hole 6, and once the solder ball 6 enters the hole 6, the solder ball 9 is swung or vibrated.
Never jump out of The solder ball 9 in the hole 6 is located at the center of the disk 4 because the disk 4 is concave at the center of the surface. In addition, in order to prevent the elastic body 5 from dropping, an elastic body fall prevention projection 7 is provided at the bottom of the hole 6 of the solder ball transfer mask 1.

A method for transferring the solder balls 9 to the substrate 10 will be described. On the substrate 10, a 150 μm to 200 μm thick metal mask with the substrate pad 11 opened is superimposed,
The flux 12 is supplied from above by printing.

Next, as shown in FIG. 2, the substrate 10 and the solder ball transfer mask 1 are aligned, and the plate 2 having the projections 3 is pressed from under the solder ball transfer mask 1. The alignment between the substrate 10 and the solder ball transfer mask 1
0 and three alignment marks provided on the solder ball transfer mask 1. The protrusion 3 pushes up the elastic body 5 and the disk 4 in the vertical direction, and presses the solder ball 9 against the substrate pad 11. This projection 3
Is 50% of the diameter of the hole 6, and when the diameter of the hole 6 is 1000 μm, the diameter of the projection 3 is 500
μm. The length of the projection 3 is set to 1 mm to 2 mm. The solder ball 9 may not be pressed against the substrate pad 11 due to the warpage of the substrate 10 or the solder ball transfer mask 1 or the variation in the diameter of the solder ball 9. The elastic body 5 supporting the solder balls 9 that have reached the substrate pad 11 is deformed, and the solder balls 9 that have not reached the substrate pad 11 also reach the substrate pad 11 as the force and pressure increase, and all the solder balls 9 It is pressed against the substrate pad 11. Since the material of the elastic body 5 is rubber or silicone resin which is deformed by a small force, the solder ball 9 pressed against the substrate pad 11 is used.
Is transferred to the substrate pad 11 by the adhesiveness of the flux 12. Thereafter, the substrate 10 is turned over and reflow is performed, so that the solder bumps 13 shown in FIG.
On top of.

[0017]

As described above, the present invention provides a structure of a jig capable of transferring all the solder balls supplied to the holes of the solder ball transfer mask onto the flux-coated substrate pad.

[Brief description of the drawings]

FIG. 1 is a sectional view of a solder ball transfer jig according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a use state of the solder ball transfer jig according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view of a solder bump formed on a substrate pad after a solder ball is transferred to a substrate pad by a solder ball transfer jig according to an embodiment of the present invention and reflowed.

FIG. 4 is a sectional view of a conventional solder ball transfer jig.

FIG. 5 is a sectional view of another conventional solder ball transfer jig.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solder ball transfer mask 2 Board 3 Projection 4 Disk 5 Elastic body 6 Hole 7 Elastic body fall prevention projection 8 Frame 9 Solder ball 10 Substrate 11 Board pad 12 Flux 13 Solder bump 14 Solder ball carrier 15 Base 16 Vacuum chamber 17 Suction hole Reference Signs List 18 suction plate 19 mesh plate 20 mask 21 through hole 22 non-through hole

Claims (3)

(57) [Claims] When a solder bump is formed on a pad on a substrate, an elastic body is inserted into a hole of a mask, and a disk having a hollow central portion is placed thereon, and a solder ball is placed on the disk. A solder ball transfer jig, which lifts the solder ball by applying a force from under the elastic body and supplies the solder ball to a pad provided with a flux of a substrate placed on the mask. 2. The solder ball transfer jig according to claim 1, wherein an elastic body drop prevention projection is provided at the bottom of the hole of the mask. 3. The solder ball transfer jig according to claim 1, wherein the member for applying a force from below the elastic body is a projection provided on a plate.