JP2000294676A - Solder ball mounting method and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solder ball mounting method and a device thereof by which tens of thousands of solder balls can be mounted on a work at a time. SOLUTION: A device for mounting solder balls is provided with a tilt table 4 which can swing, a table fixed on the tilt table 4, a mask jig 15 in which several rectangular though holes corresponding to the solder ball mounting area of a work 14 are formed and which is slidably supported by the tilt table 4, a mask 20 in which several through holes of diameter slightly larger than that of solder balls 19 and which is fixed to the mask jig 15, and a squeegee 34 which is slidably mounded on the mask jig 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for mounting a solder ball on a connection pad formed on a surface of a printed circuit board or a semiconductor wafer.

[0002]

2. Description of the Related Art One of the methods of forming a ball grid array (hereinafter, referred to as BGA) for electrically connecting a printed circuit board or a semiconductor element (hereinafter, referred to as a work) is a method for forming a ball grid array. Some are formed by melting a solder ball mounted on a pad.

[0003] In such a method of forming a BGA,
According to the position of the pad formed on the surface of the work,
Solder balls are adsorbed on a mask that has multiple holes smaller in diameter than the solder balls to be mounted, and the lower end of the solder balls is immersed in a flux bath with the solder balls adsorbed on the mask. After the flux is applied, the solder ball is mounted on the work by positioning and pressing the work on the work and by the adhesive force of the flux.

[0004]

However, since the outer diameter of the solder balls varies, when the flux is applied based on the average diameter of the solder balls used, the amount of the applied flux is smaller for the smaller diameter solder balls. Insufficient adhesive strength when mounted on a work causes a problem such that the position of a solder ball moves.

Further, when the flux is applied on the basis of a small solder ball, the flux adheres to the hole of the mask for attracting the solder ball, and even if the suction of the solder ball by the mask is released, the flux adhered to the hole is removed. In some cases, the solder ball does not separate from the mask due to the adhesive force, and the solder ball cannot be mounted on the work.

[0006] Such a phenomenon is more likely to occur as the number of solder balls mounted at a time increases, so that the number of solder balls that can be mounted at one time is usually several hundred, and at most about 1,000. It was a limit.

In view of the above circumstances, an object of the present invention is to provide a solder ball mounting method and apparatus capable of mounting tens of thousands of solder balls on a work at a time.

[0008]

In order to achieve the above-mentioned object, the invention described in claim 1 of the present application provides a method of applying the flux to a surface of a work in which the flux is previously applied to a plurality of predetermined positions. A method of mounting a solder ball, comprising disposing a mask having a plurality of holes slightly larger in diameter than the diameter of the solder ball facing the position, and mounting the solder ball at the position where the flux of the work is applied through the hole of the mask. A plurality of solder balls are supplied in advance to a space which is relatively movable with respect to the mask and is separated by a squeegee waiting at a position outside the hole forming region of the mask, and positions the mask on the surface of the work; While maintaining the relative position, the workpiece and the mask are inclined at a predetermined angle so that the standby position of the squeegee is higher, and the squeegee is moved along the mask. The moved, after reciprocating the solder balls supported by the squeegee along the mask, returning the workpiece and the mask in a horizontal state, it is separated the mask from the workpiece, and so as to unload the workpiece.

According to a second aspect of the present invention, there is provided a tilt table swingable about a horizontal axis, a tilt table swing means for swinging the tilt table via a crank mechanism, and positioning of a work. Means, and a table supported by the tilt table, and a plurality of rectangular through holes corresponding to the solder ball mounting area of the work are formed, and slidably supported by the tilt table. A plurality of through holes each having a diameter slightly larger than the diameter of the solder ball corresponding to the solder ball mounting position of the work are formed between the mask jig and the plurality of ribs formed at predetermined intervals and in contact with the work surface. A mask fixed to a surface of the mask jig opposed to the workpiece, and a parallelogram link having the tilt table as one side, wherein the parallelogram link is provided. A mask jig moving means for moving the mask jig, a squeegee holder slidably supported by the mask jig, and one end fixed to the squeegee holder, the lower end of which falls into a through hole of the mask. And a plurality of squeegees slidably inserted into the respective through holes of the mask jig up to positions where the squeegees do not come into contact with the solder balls.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 11 show an embodiment of the present invention. FIG. 1 is a plan view of a solder ball mounting device, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG.
FIG. 4 is a side view showing a drive mechanism of the tilt table in FIG.
3 is a front view showing the drive mechanism unit of FIG. 3, FIG. 5 is an enlarged view of a part B in FIG. 2, FIG. 6 is an enlarged view showing the relationship between the work, the mask and the mask jig in FIG. , FIG. 2
, FIG. 8 is a process diagram showing the start of the solder ball mounting process, FIG. 9 is a process diagram showing the mounting state in the solder ball mounting process, and FIG. 10 is a solder ball mounting process. FIG. 11 is a process diagram showing a moving end of the squeegee in the process, and FIG. 11 is a process diagram showing a finished state of the solder ball mounting process.

1 to 3, reference numeral 1 denotes a bracket fixed to a base (not shown) at predetermined intervals.
A bearing 2 is supported by the bracket 1. A tilt pin 3 is rotatably supported by the bearing 2. 4
Is a tilt table fixed between the tilt pins 3. Therefore, the tilt table 4 is supported rotatably about the axis of the tilt pin 3.

1, 3 and 4, reference numeral 5 denotes a bracket fixed to the base. Reference numeral 6 denotes a tilt motor, which is fixed to the bracket 5. Reference numeral 7 denotes a flange fixed to the rotation shaft of the tilt motor 6. Reference numeral 8 denotes a crank pin fixed to an eccentric position of the flange 7. Reference numeral 9 denotes a crank plate which is rotatably supported by the crank pin 8. Reference numeral 10 denotes a crank pin, which connects the tilt table 4 and the crank plate 9.

Therefore, when the crank pin 8 is at the lower end position, the tilt motor 6 moves the flange 7 to 18 degrees.
When rotated by 0 degrees, one of the tilt tables 4 is pushed up via the crank pins 8, the crank plates 9, and the crank pins 10, and the tilt table 4 rotates about the axis of the tilt pins 3 to tilt the tilt table 4. Further, when the flange 7 further rotates 180 degrees from this state, one of the tilt tables 4 is pulled down via the crank pins 8, the crank plates 9 and the crank pins 10, and the tilt tables 4 are returned to the horizontal state.

The tilt angle θ of the tilt table 4 is
It is desirable to set an angle (for example, about 20 ° to 30 °) at which the solder ball rolls down on a mask described later by its own weight and easily falls into a through hole formed in the mask.

With such a structure, when the tilt table 4 is tilted or returned to a horizontal state, acceleration and deceleration can be smoothly performed at the time of starting and stopping, and unnecessary vibration of the work 14 can be achieved. Never give.

1 to 7, reference numeral 11 denotes a table which is supported by the tilt table 4. A vacuum suction pocket 12 is formed on the upper surface of the table 11 and connected to a vacuum supply source via a vacuum suction circuit 13. Reference numeral 14 denotes a work, which is fixed to the table 11 by vacuum suction.

The upper surface of the table 11 is provided with a groove for restraining the outer shape of the work 14 for horizontal positioning and a notch formed in the work 14 in a rotational direction. Positioning means (not shown) for positioning may be provided.

Reference numeral 15 denotes a mask jig, in which a plurality of rectangular through holes 16 are formed in parallel, and a rib 17 is formed between the holes. A guide pin 18 slidably penetrates a guide hole formed in the tilt table 4, and one end thereof is fixed to the lower surface of the mask jig 15.

19 is a solder ball. Reference numeral 20 denotes a mask, and a plurality of through holes 21 having a diameter slightly larger than the diameter of the solder ball 19 is provided at a position corresponding to the solder ball mounting position of the work 14.
Then, a rib 22 is formed which contacts the work in the area where the solder ball 19 of the work 14 is not mounted, and prevents the contact between the area where the solder ball 19 of the work 14 is mounted and the mask 20, and is fixed to the mask jig 15. ing.

This mask 20 can be formed of a metal plate. Also, for example, a through hole 2 is formed in a single-sided copper clad laminate.
After the first hole is formed, the copper foil in the region where the through hole 21 is formed may be removed by etching.

In FIG. 7, reference numeral 23 denotes an arm pin fixed to the tilt table 4. A link arm 24 is rotatably supported by the arm pin 23. 2
Reference numeral 5 denotes an arm rod, which is fixed to a link arm 24. Reference numeral 26 denotes a parallel link, which is rotatably supported by an arm rod 25. The tilt table 4, the link arm 24, and the parallel link 26 form a parallelogram link. When the parallel link 26 is at the lower end of the moving area, the parallel link 26 faces the lower end of the guide pin 18 with a slight gap. are doing.

A bracket 27 is fixed to the base. Reference numeral 28 denotes a cylinder fixed to the bracket 27, and a rod 29 thereof is opposed to the arm rod 25.

Therefore, when the rod 29 pushes the arm rod 25 by the operation of the cylinder 28, the link arm 2
4 swings and the height of the parallel link 26 increases by h,
The mask jig 15 can be pushed up by the height via the guide pins 18.

The operation of the cylinder 28 causes the rod 2
9 moves back from the arm rod 25, the mask jig 15
The mask jig 15 is lowered by the weight of another member mounted on the mask jig 15.

The movement amount h of the mask jig 15 is
1 between the upper surface of the mask 1 and the lower surface of the mask 20 (for example, 6.
(about 10 mm to about 10 mm).

With such a configuration, when the mask 20 is brought into contact with the work 14 or when the work 14
When the mask 20 is moved away from the mask 20, the moving speed of the mask 20 can be reduced. Therefore, even if the solder ball 19 and the inner peripheral surface of the through hole 21 of the mask 20 are in contact with each other, the solder ball 19 and the mask 20 can be separated. The mask 20 can be surely separated without moving the solder ball 19 when separating, and an unnecessary impact is not given to the work 14.

In FIGS. 1, 2 and 5, a guide rail 30 is fixed to the mask jig 15.
A linear motion bearing 31 is slidably supported by the guide rail 30. A holder 32 has a groove 33 formed in a side surface thereof, and is fixed to the linear motion bearing 31. Reference numeral 34 denotes a squeegee whose lower part is slidably inserted into the through hole 16 of the mask jig 15 and is fixed to the holder 32.

The lower end of the squeegee 34 and the mask 20
Is set to a size smaller than the radius of the solder ball 19 supplied on the mask 20 and the squeegee 34 does not contact the top of the solder ball 19 dropped into the through hole 21 of the mask 20. ing. Also, the gap between the rib 17 and the squeegee 34 is set smaller than the radius of the solder ball 19.

A guide rail 35 is fixed to the tilt table 4 in parallel with the guide rail 30.
A linear motion bearing 36 is slidably supported by the guide rail 35. A driving hook 37 is a linear motion bearing 36 so as to be detachably fitted into the groove 33 of the holder 32.
It is fixed to.

The driving hook 37 is driven by belt driving means (not shown) and moves at a predetermined speed along the guide rail 35. Then, the squeegee 34 is moved via the holder 32.

The speed at which the squeegee 34 is moved is set by appropriately selecting a speed at which the solder balls 19 rolling down on the mask 20 can surely fall into the holes 21 of the mask 20. For example, when the tilt angle of the tilt table 4 is 25 degrees and the diameter of the solder ball 19 is 0.4 mm, the moving speed of the squeegee 34 can be set to about 10 to 30 mm / sec.

With such a configuration, one end of the through hole 16 of the mask jig 15 and the squeegee 34 set at the standby position in advance
2 to 3 times the number of solder balls 1 supplied to the work 14 through the mask 20 in the space formed between
9 is supplied.

When the cylinder 28 is operated while the tilt table 4 is horizontal, the rod 29 is protruded and the arm rod 25 is pushed, so that the mask jig 15 is raised and the required space between the table 11 and the mask 20 is increased. To form

Through this interval, the work 14 is supplied and positioned on the table 11, and a vacuum pressure is supplied to the vacuum suction pocket 12 of the table 11 from the vacuum supply means to fix the work 14 to the table 11.

By operating the cylinder 28 to retract the rod 29, the mask jig 15 is lowered, and the rib 22 of the mask 20 is brought into contact with the upper surface of the work 14.

In this state, the tilt motor 6 is operated,
As shown in FIG. 8, the tilt table 4 is inclined at an angle θ. At this time, the table 11 and the mask jig 15 are also inclined at the same time. At this time, since the solder ball 19 is supported by the squeegee 34, it does not fall by its own weight.

In the drawing, F is a flux applied to the solder ball mounting position of the work 14.

In this state, the squeegee 34 is moved downward from driving means (not shown) via the driving hook 37. Then, as shown in FIG. 9, the solder ball 19 rolls down on the mask 20 by its own weight as the squeegee 34 moves.

At this time, the solder balls 19 in the vicinity of the squeegee 34 roll down in an overlapping state as shown in the figure, but the rear side spreads into the through-hole 16 and extends over the entire surface.
It rolls down in the state of a layer. Therefore, squeegee 3
By appropriately setting the moving speed of 4, the solder ball 19 can be reliably dropped into the through hole 21.

Thus, the through-hole 21 of the mask 20
The solder ball 19 passing above falls through the through hole 21 onto the flux F applied to the work 14 arranged below the through hole 21. When one solder ball 19 enters one through hole 21, the subsequent solder ball 19 becomes
The ball rolls over the solder ball 19 in the through hole 21.

As shown in FIG. 10, when the squeegee 34 moves to the lower end, one solder ball 19 falls into all the through holes 21 formed in the mask 20, and
It is held by the adhesive force of the flux F and mounted on the work 14.

In this state, by returning the squeegee 34 to its standby position, the surplus solder balls 19 that have moved downward together with the squeegee 34 are pushed by the squeegee 34 and returned to the standby position. To get over the solder ball 19 that has fallen into the
1 is pushed into the flex F, and the solder ball 1
9 is ensured.

In this state, the tilt motor 6 is operated,
As shown in FIG. 11, the tilt table 4 is returned to a horizontal state. Then, the mask jig 15 is raised by the cylinder 28 and the work 14 is taken out.

According to the above embodiment, the tilt table side and the mask jig side can be separated between the holder 32 and the driving hook 37, so that the mask jig side can be adjusted according to the type of work. By preparing a plurality of types, works of a plurality of types can be easily adapted.

[0045]

As described above, according to the present invention, even if the number of solder balls to be mounted is tens of thousands or more, the required number of solder balls can be reliably mounted in one operation. Can be. Further, since the operation can be performed by a simple operation, the operation is easy and the operation efficiency can be improved.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a side view showing a drive mechanism of the tilt table in FIG. 1;

FIG. 4 is a front view showing the drive mechanism of FIG. 3;

FIG. 5 is an enlarged view of a portion B in FIG. 2;

FIG. 6 is an enlarged view showing a relationship between a work, a mask, and a mask jig in FIG. 1;

FIG. 7 is a sectional view taken along the line CC in FIG. 2;

FIG. 8 is a process diagram showing a start time of a solder ball mounting process.

FIG. 9 is a process diagram showing a mounting state in a solder ball mounting process.

FIG. 10 is a process diagram showing a moving end of a squeegee in a solder ball mounting process.

FIG. 11 is a process diagram showing an end state of a solder ball mounting process.

[Explanation of symbols]

4 ... Tilt table, 6 ... Tilt motor, 7 ... Flange, 8 ... Crank pin, 9 ... Crank plate, 10 ...
Crank pin, 11 ... Table, 14 ... Work, 15 ...
Mask jig, 16 through hole, 17 rib, 18 guide pin, 19 solder ball, 20 mask, 21 through hole, 24 link arm, 25 arm rod, 26
Parallel link, 30: guide rail, 32: holder, 34
Squeegee,

Claims (2)

[Claims] 1. A mask having a plurality of holes slightly larger than the diameter of a solder ball opposed to a position where the flux is applied is disposed on the surface of the work to which the flux is applied at a plurality of predetermined positions in advance. A solder ball mounting method for mounting a solder ball at a flux application position of a work through a hole of the mask, wherein the squeegee is movable relative to the mask, and stands by at a position outside a hole forming region of the mask. A plurality of solder balls are supplied in advance to the space provided, the mask is positioned on the surface of the work, and the work and the mask are held at a predetermined angle so that the standby position of the squeegee is raised while maintaining the relative position of the work and the mask. Tilt, reciprocate the squeegee along the mask, and move the solder balls supported by the squeegee along the mask. After backward movement, returning the workpiece and the mask in the horizontal state, the mask is separated from the workpiece, the method for mounting solder balls, which comprises carrying out the work. A tilt table swingable about a horizontal axis; a tilt table swing means for swinging the tilt table via a crank mechanism; a work positioning means and a work fixing means. A table supported by the tilt table, a plurality of rectangular through holes corresponding to the solder ball mounting area of the work, and a mask jig slidably supported by the tilt table; A plurality of through holes each having a diameter slightly larger than the diameter of the solder ball corresponding to the solder ball mounting position of the work are formed between the plurality of ribs formed in contact with the surface of the work, and And a parallelogram link having the tilt table as one side, and the mask jig is moved by the parallelogram link. Squeegee moving means, a squeegee holder slidably supported by the mask jig, and a position where one end is fixed to the squeegee holder and the lower end of the squeegee holder does not come into contact with the solder ball dropped into the through hole of the mask. A solder ball mounting device, comprising: a plurality of squeegees slidably inserted into respective through holes of the mask jig.