JP2000022035A - Solder ball alignment method, alignment mask, and alignment mask holding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform an operation and to arrange 20,000 to 30,000 solder balls at one time. For example, even in the case of an 8-inch wafer, the entire area is soldered by one operation. A solder ball alignment method and a solder ball alignment mask holding device capable of aligning balls. SOLUTION: Solder balls 6 having more than the number of holes 4a are supplied to a mask 4, and both are inclined while maintaining a distance between the mask 4 and a work 2, so that excess solder balls 6 having more than the number of holes 4a are provided. Is removed from the mask 4, and then the mask 4 is moved away from the work 2. Before the mask 4 is moved away from the work 2, the solder balls 6 are rolled over the entire mask 4 by inclining them in opposite directions, so that the solder balls 6 can be reliably positioned in the holes 4 a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder ball aligning method, an aligning mask, and an aligning mask holding device for positioning a solder ball at a position of a pad arranged on a surface of a work such as a printed circuit board or a wafer. About.

[0002]

2. Description of the Related Art The ball grid array method (hereinafter referred to as BGA)
It is called the law. In the case of), the solder ball is adsorbed on a mask that has a hole smaller in diameter than the solder ball corresponding to the pad position on the work surface, and the solder ball is slightly immersed in a flux bath with the adsorbed solder ball. The flux was applied, and the solder ball was positioned on the pad via the applied flux.

[0003]

However, since the outer diameter of the solder ball varies, in the case of the BGA method, if the flux is applied in accordance with the small-diameter solder ball, the flux may adhere to the mask. In some cases, the solder ball did not separate from the mask even when the suction was stopped.
For this reason, the tolerance of the outer diameter of the ball must be small, and the height and flatness of the flux surface must be constantly controlled, and the work efficiency cannot be improved. Also,
The number of solder balls that can be aligned at one time is 10
Up to about 00 pieces.

An object of the present invention is to solve the above-mentioned problems,
Solder balls that are easy to work and can align 20,000 to 30,000 solder balls at a time. For example, even for an 8-inch wafer, solder balls can be aligned in one operation over the entire area. And an apparatus for holding a mask for aligning solder balls.

[0005]

In order to solve the above-mentioned problems, a first aspect of the present invention is to provide a mask having a hole having a diameter larger than the diameter of a solder ball by using a mask having a surface coated in advance with a flux. And the solder balls are supplied to the holes from the side of the mask that does not face the surface of the work, and the solder balls are positioned at pad positions arranged on the surface of the work. In the method for aligning solder balls, the solder balls are supplied to the mask in a number greater than the number of the holes,
By tilting the mask and the work while maintaining the distance between the mask and the work, after removing excess solder balls larger than the number of holes from the mask, the mask is moved away from the work. .

In this case, the solder balls are prevented from coming off in a direction parallel to the surface of the mask, and the distance between the mask and the work is maintained before the solder balls are removed from the work. It is more effective to tilt both of them alternately in opposite directions with respect to an axis parallel to the horizontal plane, or to apply vibration to the mask when removing excess solder balls from the mask.

Also, in a solder ball alignment mask provided with holes having a diameter larger than the diameter of the solder balls in the same pattern as the positions of the pads arranged on the surface of the work, the holes on the side facing the surface of the work are provided. A rib-shaped liner is provided at a position where the liner does not overlap.

Also, in a solder ball alignment mask holding device provided with a hole having a diameter larger than the diameter of the solder ball in the same pattern as the position of a pad arranged on the surface of the work, the main body is formed on a surface holding the mask. The size of the inner wall surface at right angles to the cylindrical shape is a size including all the holes, and a rib-shaped pressing member is provided at a position that does not overlap with the hole on the side of the mask not facing the work surface. It is characterized by.

In this case, it is more effective to provide at least one entrance / exit for allowing the solder ball to enter / exit at a position of the inner wall in contact with the mask, or to provide a sealing means at the entrance / exit.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a main part of a solder ball mounting apparatus according to the present invention, FIG. 2 is a plan view of a main part, and FIG.
FIG. Reference numeral 1 denotes a work mounting base, on the surface of which is formed a hole 1c whose diameter is slightly larger than the outer diameter of the work 2 and whose depth is slightly smaller than the thickness of the work 2. Also,
The holes 1a and 1b are connected to a suction device not shown. In addition, a hole 1d is provided centered on the inner peripheral portion of the hole 1c. Reference numeral 2 denotes a disk-shaped work, on which a large number of pads 2a are formed on a surface (an upper surface not in contact with the work mounting base 1), and a flux (not shown) is applied to a predetermined thickness in advance. I have. As shown in FIG. 3, a substantially semicircular notch 2b is formed on the side surface of the work 2. The work 2 is fitted in the hole 1c.

Reference numeral 3 denotes a first liner mask. The hole 3a of the liner mask is larger than the outer diameter of the work 2. Reference numeral 4 denotes an alignment mask, in which mask holes 4a larger than the diameter of the solder balls 6 by a predetermined dimension (about 1.15 times the diameter of the solder balls 6) are formed in the same pattern as the pads 2a.
Since the number of the pads 2a is 20,000 to 30,000, two rows are representatively shown in FIG. 2 and other plan views described later. The thickness of the alignment mask 4 is about 0.6 to 0.8 times the diameter of the solder ball 6. Reference numeral 5 denotes a second liner mask having a thickness of C1 and a lower surface of the alignment mask 4 (work 2).
A plurality of rows are arranged at positions where the mask holes 4a on the (side surface) are not closed, and opposed to a pressing member 8 described later.

Reference numeral 7 denotes a rectangular mask jig which holds the liner mask 3, the alignment mask 4, and the liner mask 5 integrally. The central portion of the mask jig 7 has a hollow space 7a large enough to receive all the mask holes 4a therein, and the depth connecting the hollow space 7a and the outer end face is the mask jig 7.
A groove 7b is formed which is sufficiently larger than the cross-sectional area of the solder ball 6 whose entrance portion is tapered. A hole 7c in a direction orthogonal to the groove 7b is provided at an intermediate portion of each groove 7b. Reference numeral 8 denotes a pressing member which has a horizontal end parting the adjacent groove 7b, a vertical end part contacting the upper surface of the alignment mask 4, and keeping the flatness of the alignment mask 4 in the hole 4b.
It is arranged in the hollow space 7a so as not to overlap with a.

Reference numeral 9 denotes an electromagnetic cylinder which is fixed to the upper surface of the mask jig 7, and when a switch (not shown) is closed, a shaft 9a fitted into the hole 7c closes the groove 7b.
Reference numeral 10 denotes a pair of linear guide devices, which are held by the mask jig 7 and are engaged with a pair of guide pins 11 fixed to the work mounting base 1. When the linear guide device 10 is engaged with the guide pins 11, the mask jig 7 is positioned with respect to the holes 1c and 1d.

A collection box 20 is fixed to the side of the mask jig 7 where the groove 7b is formed. 21 is a tilting device,
The workpiece mounting base 1 is inclined at a predetermined angle with respect to the axis O at the center position of the hole 1c in a direction perpendicular to the direction in which the holding member 8 is arranged. In FIG. 5 described later, reference numeral 22 denotes a guide pin, which is vertically moved by a positioning device (not shown) so as to fit into the hole 1d.

Next, the operation will be described. FIG. 4 is a view showing the progress of positioning the work 2 on the work mounting base 1, and FIG. 5 is an enlarged view of a portion B in FIG. The work mounting base 1 is positioned horizontally. At first, work 2 installation,
The alignment procedure will be described. The flux on the surface of the work 2 has a predetermined thickness (however, less than C1).
It is applied to. 1. Align the notch 2b approximately with the hole 1d and insert the work 2 into the hole 1c
To place. 2. The hole 1b is connected to a compressed air source (not shown), and compressed air is supplied to the hole 1c through the hole 1a to slightly float the work 2. 3. Lower the guide pin 22 so that the notch 2b is in the hole 1d.
Position. 4. The hole 1b is connected to a vacuum source (not shown), and the work 2 is fixed to the work mounting base 1 via the hole 1a. 5. The guide pin 22 is raised.

Next, a procedure for aligning solder balls will be described with reference to FIGS. 6 and 8 are side views showing the progress of the operation, and FIGS. 7 and 9 are plan views. In addition, the code | symbol is attached | subjected only to the minimum thing. a. The mask jig 7 is inserted into the guide pins 11, and the liner mask 5 is brought into contact with the surface of the work 2. b. The electromagnetic cylinder 9 is closed, and the groove 9b is closed by the shaft 9a. c. The solder ball 6 is supplied to the space 7a. In this case, the number of the solder balls 6 is set to a number sufficiently larger than the number of the mask holes 4a. Then, as shown in FIGS. 6 and 7, the solder balls 6 enter into most of the mask holes 4a, and a part of them is stacked. d. The tilting device 21 is operated, and as shown in FIG. 8, after tilting to the right by θ degrees (about 10 to 15 degrees), the tilt is tilted to the right by θ degrees, and then tilted to the right by θ degrees again. By this operation, the solder balls 6 roll on the mask 4, and the solder balls 6 are supplied to all the mask holes 4a and are held by the flux. e. The electromagnetic cylinder 9 is opened in the state shown in FIG. Then, the surplus solder balls 6 that have not entered the mask holes 4 a roll and move to the collection box 20. The recovered solder balls 6 are used again. f. Make the work mounting base 1 horizontal. g. The mask jig 7 is removed upward.

By the above operation, the solder balls 6 are aligned, that is, positioned on the pads 2a. And
The work 2 is moved to a heating device (not shown) to melt the solder balls 6 to form bumps.

In the above embodiment, the notch 2b is aligned with the hole 1d in a state where the work 2 is levitated by the compressed air, so that the work 2 is easily rotated, and the amount of deviation in the rotation direction is corrected. In addition, the surface is not damaged.

In the above procedures d and e, if a slight vibration is applied to the mask jig 7, the positioning of the solder balls 6 in the mask holes 4a and the movement to the collection box 20 can be further ensured. Work time can be reduced.

In step g, when the solder balls 6 are pressed against the flux by means not shown in the figure to slightly push them into the flux, the solder balls 6 are held by the adhesive force of the flux and the positioning is ensured.

Further, a reference mark is provided on the work 2 instead of the positioning by the guide pin 22, and the work 2
A means for rotating and positioning the inside of the hole 1c may be provided, and for example, the positioning may be performed by the reference mark by a CCD camera.

Although the electromagnetic cylinders 9 are provided in all the grooves 7b, a vertically movable shutter is provided on the end face of the mask jig 7 on the collection box 20 side, and all the grooves 7b are provided by one shutter.
b may be blocked.

The shape of the work is not limited to a disk shape, and any means can be selected as a means for positioning the mask hole 4a and the pad 2a.

[0024]

As described above, according to the present invention,
Even if the number of the pads 2a and the number of the mask holes 4a are respectively 20 to 30,000, the solder balls 6 can be surely aligned by one operation. Therefore, even in a large area such as the entire area of an 8-inch wafer, the solder balls can be aligned in one operation, and the operation is easy and the operation efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of a solder ball mounting apparatus according to the present invention.

FIG. 2 is a plan view of a main part of the solder ball mounting apparatus according to the present invention.

FIG. 3 is a view as viewed in the direction of arrows AA in FIG. 2;

FIG. 4 is a diagram showing the progress of a procedure for positioning a work on a work mounting base.

FIG. 5 is an enlarged view of a portion B in FIG. 4;

FIG. 6 is a side view showing the progress of the operation.

FIG. 7 is a plan view showing the progress of the operation.

FIG. 8 is a side view showing the progress of the operation.

FIG. 9 is a plan view showing the progress of the operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Work 4 Alignment mask 4a Mask hole 6 Solder ball

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/34 505 H01L 21/92 604H 604Z

Claims (7)

[Claims] 1. A mask provided with a hole having a diameter larger than the diameter of a solder ball is positioned vertically and horizontally with respect to the surface of a work to which a flux has been previously applied, and the solder ball is positioned on the work of the mask. The solder balls are supplied from the side not facing the surface of the work to the holes, and the solder balls are positioned at pad positions arranged on the surface of the work, wherein the solder balls are larger than the number of the holes. To the mask, and by tilting the mask and the work while maintaining the distance between the mask and the work, after removing excess solder balls larger than the number of holes from the mask, the mask is removed from the work A method for aligning solder balls, characterized in that the solder balls are kept away from the solder balls. 2. The solder ball is prevented from coming off in a direction parallel to the surface of the mask, and before removing the solder ball from the work, the solder ball is kept in a state where the distance between the mask and the work is maintained. 2. The method of claim 1, wherein the semiconductor chips are alternately inclined in directions opposite to each other with respect to an axis parallel to a horizontal plane. 3. 3. The solder ball alignment method according to claim 1, wherein a vibration is applied to the mask when removing excess solder balls from the mask. 4. A mask for aligning solder balls having holes larger in diameter than the diameter of the solder balls in the same pattern as the positions of pads arranged on the surface of the work, wherein the holes on the side facing the surface of the work are arranged. A solder ball alignment mask, wherein a rib-shaped liner is provided at a position not overlapping with the solder ball. 5. An apparatus for holding a mask for aligning solder balls, comprising a hole having a diameter larger than the diameter of the solder balls in the same pattern as the positions of pads arranged on the surface of the work.
The main body has a cylindrical shape whose inner wall surface perpendicular to the surface holding the mask has a size including all the holes, and a rib is provided at a position where the hole does not overlap with the hole on the side not facing the surface of the work of the mask. A holding device for a mask for aligning solder balls, wherein a holding member having a shape of a circle is provided. 6. The solder ball alignment mask holding apparatus according to claim 5, wherein at least one entry / exit port through which the solder balls enter / exit is provided at a position of the inner wall in contact with the mask. 7. The apparatus according to claim 5, wherein a sealing means is provided at the entrance.