JPH07202401A - Method and apparatus for feeding metal bump - Google Patents

Abstract

PURPOSE:To provide a method and apparatus for facilitating the supply of stabilized quantity of specific metal bumps for fusing a connecting medium on a substrate. CONSTITUTION:Spherical connecting media 26 of specific metal having uniform diameter are sucked by means 24, 25 having a plurality of suction holes arranged at a predetermined pitch and carried to a subject. This method allows to supply a stabilized quantity of metal bumps onto a subject by a relatively simple process.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Industrial Application Conventional Technology (FIGS. 5, 6 and 7) Problems to be Solved by the Invention Means for Solving the Problems (FIGS. 1, 3 and 4) Operation (FIGS. 1, 3 and 4) FIG. 4) Example (FIGS. 1 to 4) Effect of the invention (FIGS. 1, 3 and 4)

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for supplying metal bumps, and is suitable for application to, for example, supplying solder to a printed wiring board.

[0003]

2. Description of the Related Art Conventionally, as a solder supply method, a solder paste supply method, a solder supply method to a component electrode, and a solder precoat method to a substrate land have been proposed. FIG. 5 shows a method of mounting the surface mount component on the printed wiring board. A substrate land 2 is provided on the printed wiring board 1, and a solder paste 3 is applied on the base land 2 (FIG. 5A).

In this state, the surface mount components 4 and 5 are aligned and mounted so as to bridge the board lands 2 (FIG. 5B). Then, by reflowing the printed wiring board 1, the solder paste 3 is melted and the surface mount components 4 and 5 can be bonded to the solder paste 3 on the board land 2 (FIG. 5C). Such a solder paste supply method includes a printing method, a dispersion method, and the like.

As a method of supplying solder to component electrodes, an IC is used.
Self-solder method for leads (self-solder-QFP),
There is a transfer bump method or the like. The self-solder method is a method of depositing solder on an IC lead by electrolytic plating. For example, as shown in the vertical cross section of the IC lead 6 after soldering in FIG. 6, the entire surface of the IC lead 6 is covered with the soldering 7.

In the transfer bump method, solder is deposited by electrolytic plating so as to correspond to the substrate land, and the bare chip or T
This is a method of transferring to the electrode of CP. For example, as shown in FIG. 7, a square opening 8 is formed at the center of the resin film 8.
A is formed, and four leads 9 in parallel with each other are attached across the resin film 8 and the opening 8A so as to be orthogonal to the four sides on the same surface of the opening 8A. . In this case, the tip of the lead 9 on the side of the opening 8A is Sn or Au plated (FIG. 7A).

On the surface of the bump forming substrate 10, bumps 11 arranged in a pitch so that they can be aligned with the parts of the resin film 8 on which the leads 9 of the resin film 8 have been plated are welded. (FIG. 7 (B)).
In this state, the bumps 11 welded on the bump forming substrate 10 are thermocompression-bonded to transfer-bond the bumps 11 to the tips of the leads 9 provided on the resin film 8 (FIG. 7C). ).

Subsequently, the LSI chip 12 is connected to the bump 1 described above.
1 is connected to the formed resin film 8. In this case, an aluminum electrode 13 is provided at a predetermined position on the surface of the LSI chip 12 (FIG. 7 (D)), and the aluminum electrode 13 is heated and pressed to fuse the melted bumps 11 to the LSI chip 13 The chip 12 can be connected to the resin film 8 (FIG. 7 (E)).

At this time, by heating and pressing the bump 11, the oxide film covering the surface of the aluminum electrode 13 is destroyed, and the aluminum and the bump 1 on which impurities are not attached are bumped.
Thus, Au and Al are joined together to form an Au / Al joint at a time. Next, there are methods of solder precoating on the board land such as super solder and partial peeling method.The solder precoating on the board land does not specify the component, and the solder supply to the minute land, which is difficult by solder paste printing. It is effective because it can be done.

The super solder method is a method of depositing solder for each land by a chemical reaction of a special paste.
Further, the printing precoat method is a method of forming a precoat by reflowing without mounting components after printing solder paste. The partial peeling method is a method of forming a precoat by peeling the solder used as a mask at the time of manufacturing a printed wiring board leaving only the land portion.

[0011]

By the way, in the solder paste supplying method, when the dispersion method is used, it becomes difficult to apply and control the amount of solder to a minute substrate land. , 0.3
[Mm] It becomes difficult to stably supply solder to a minute board land such as a pitch IC or 1005 component. Therefore, as the density of printed wiring boards and the miniaturization of parts progress, it becomes impossible to meet the demand for higher accuracy of the amount of solder supplied to the parts land.

Further, in the supply of solder to the component electrodes, the self-solder method and the transfer bump method both complicate the process by using electrolytic plating. Further, since the parts are specified by the method of supplying the solder to the parts, it becomes difficult to supply the solder corresponding to all the parts, which lacks versatility.

In addition, in the method of pre-coating the solder on the substrate land, it is necessary to use a special paste by the super solder method, or the dispersion of the solder is +100 [%] (for example, 50 [μm]) in size.
In the case of +50 [μm]) and -50% (for example, 50 [μm]
m] becomes as large as −25 [μm]), and bumps cannot be easily formed.

Further, according to the printing precoating method, it is difficult to supply solder with high accuracy even though printing for exclusive use of precoating (thinner than the screen used at the time of mounting and having good printability) is used. In addition, the partial peeling method complicates the process of forming the solder precoat because it is necessary to use electrolytic plating.

The present invention has been made in view of the above points, and is intended to propose a metal bump supplying method and apparatus for supplying a stable amount of metal bumps relatively easily. is there.

[0016]

In order to solve the above problems, the present invention provides a metal bump supplying method for supplying a metal bump as a connection medium 26 made of a predetermined metal onto a supply target 29 by using a predetermined metal. The spherical connecting medium 26 having a uniform diameter is adsorbed by the adsorbing means 24 and 25 having a plurality of suction holes 27 arranged in a predetermined pitch, and the connecting medium 26 adsorbed by the adsorbing means 24 and 25 is removed. It is conveyed to the supply target 29.

Further, in the present invention, in the metal bump supply device 20 for supplying the metal bump as the connection medium 26 made of a predetermined metal onto the supply target 29, the spherical shape having a uniform diameter made of the predetermined metal is unified. Connection medium 26,
Adsorption means 24, 25 for adsorbing the connection medium 26 to the plurality of suction holes 27 arranged in a predetermined pitch are provided, and the connection medium 26 adsorbed by the adsorption means 24, 25 is conveyed onto the supply target 29. To do.

[0018]

A spherical connecting medium 26 having a uniform diameter made of a predetermined metal is sucked by suction means 24 and 25 having a plurality of suction holes 27 arranged in a predetermined pitch, and the suction means 2 is used.
By transporting the connection medium 26 adsorbed by the Nos. 4 and 25 to the supply target 29, a stable amount of metal bumps can be supplied onto the supply target 29 by a relatively simple process.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 20 denotes a solder supply device as a whole, which is composed of a driving device 21 and a laser-equipped tool 22 attached to a lower portion thereof, and an XY direction driving arm 23 attached to a side surface of the driving device 21. Thus, the solder supply device 20 can be moved in the directions of the X axis and the Y axis.

The laser-equipped tool 22 is supported by a driving device 21 so as to be movable downward or upward in a direction indicated by an arrow Z or in a direction opposite thereto, and a laser heating control means (not shown). The intensity of the laser light is controlled by (1). A suction jig 24 is attached to the lower end of the tool 22 with a laser, and the suction jig 2
A screen 25 is attached to the lower side surface of the screen 4. A predetermined vacuum pump (not shown) capable of sucking and holding the screen 25 and the ball solder 26 by applying a vacuum pressure is provided in the suction jig 24.

A plurality of suction holes 27 arranged in a predetermined pitch are formed in the screen 25, and the arrangement state of the suction holes 27 matches the arrangement state of the board lands on which solder bumps are to be formed. It is done like this. A ball solder bath 28 is provided at a position facing the screen 25, and a plurality of ball solders 2 are provided on the surface of the ball solder bath 28 facing the screen 25.
6 are laid out. The ball solders 26 are all made of solder having a spherical shape with a uniform diameter, and the width of the suction holes 27 formed in the screen 25 is smaller than the diameter of the ball solders 26.

A printed wiring board 29 is provided at a predetermined position apart from the ball solder bath 28, and the screen 25 attracted to the lower end of the suction jig 24 is controlled by the drive control of the XY drive arm 23. By moving, the screen 25 is aligned with the printed wiring board 29. Printed wiring board 29
A substrate land 30 is provided on the upper side surface, and a flux 31 is applied to the surface of the substrate land to prevent oxidation.

FIG. 2 shows the suction hole 27 of the screen 25.
Showing the arrangement state of the plurality of suction holes 27 and the screen 25
Two rows of 0.3 mm pitches are arranged alternately on the outermost circumference of the. By using the ball solder 26 made of a spherical solder alloy having a uniform diameter, the amount of the solder alloy can be easily controlled, unlike the solder paste in which the shape is not constant. By being able to purchase it, you do not have to go through the complicated process of electroplating. Moreover, the user is free to choose the composition of the solder alloy.

Here, as shown in FIG. 3, the solder supply device 20 positions the laser-equipped tool 22 on the ball solder bath 28 under the control of the driving device 21 (FIG. 3 (A)), and thereafter By moving the attached tool 22 downward, the screen 25 adsorbed on the lower end of the adsorption jig 24 attached to the lower end of the laser attached tool 22 can be brought close to the upper surface of the ball solder bath 28. it can.

In this state, the vacuum pressure is applied to each suction hole 27 formed in the screen 25 by a predetermined vacuum pump (not shown), so that the balls in the ball solder bath 28 are The solder 26 is the suction hole 2
7 is adsorbed and held (FIG. 3 (B)). When the ball solder 26 sucked and held in the suction holes 27 of the screen 25 is moved to align with the printed wiring board 29, the tool 22 with the laser is used to suck the ball solder 26 under the control of the driving device 21. Move up while being adsorbed on.

FIG. 4 shows the step of welding the ball solder 26 described above with reference to FIG. 3 to the printed wiring board 29. The ball solder 26 is adsorbed by the suction holes 27 of the screen 25 and the XY direction drive arm 23 is held. The ball solder 26 can be aligned with the board land 30 of the printed wiring board 29 by moving it under drive control (FIG. 4A).

In this state, the laser-equipped tool 22 is lowered to bring the ball solder 26 into contact with the substrate land 30, and then the ball solder 26 in the suction hole 27 of the screen 25 is controlled under the control of the drive unit 21.
Try to release the adsorption of. At this time, since the flux 31 applied to the surface of the board land 30 has adhesiveness, the ball solder 26 can be temporarily fixed on the board land 30.

Thereafter, a laser heating control means (not shown) radiates the laser light of the tool 22 with a laser through the suction jig 24 to heat and melt the ball solder 26, so that the ball solder 26 is removed. It can be bonded to the substrate land 30 (FIG. 4B).

At this time, the flux 31 is thermally decomposed and vaporized, and evaporated from the surfaces of the printed wiring board 29 and the board land 30. Thereafter, by stopping the emission of the laser light, the ball solder 26 is solidified, and the tool 22 with the laser is further moved upward to complete the formation of the solder precoat on the board land 30 (FIG. 4).
(C)).

In the above structure, by using the ball solder 26 made of a spherical-shaped solder alloy having a uniform diameter, a stable amount of solder can be adhered to the board land 30, and therefore solder connection is made. It is possible to obtain a stable soldering quality in which no missing portion is generated.

Further, by melting and joining the ball solder 26 adsorbed in the suction holes 27 of the screen 25, the process of forming a solder precoat on the printed wiring board 29 can be performed relatively easily. Further, by using the tool 22 with a laser, the ball solder 26
Since it can be performed by a series of operations from the adsorption to the transfer of, the overall process can be facilitated.

According to the above construction, the spherical ball solder 26 made of a solder alloy and having a uniform diameter is adsorbed to the screen 25 having a plurality of suction holes 27 arranged in a predetermined pitch and adsorbed to the screen 25. By transferring the ball solder 26 to the substrate 29, a stable amount of metal bumps can be obtained by a relatively simple process.
9 can be supplied.

In the above-described embodiment, when the ball solder 26 contacts the substrate land 30, the laser heating control means (not shown) emits the laser beam of the laser-equipped tool 22 and the ball solder 26. However, the present invention is not limited to this, and the ball solder 26 is heated and melted by sending hot air through the adsorption jig 24 by the heating control means (not shown) of the heater. You may do it.

Further, in the above-mentioned embodiment, the screen 2 having a plurality of suction holes 27 arranged in a predetermined pitch.
5, a vacuum pressure is applied to the suction holes 27 by a predetermined vacuum pump (not shown) provided in the suction jig 24 to suck the ball solder 26 in the ball solder bath 28. The case where the suction jig 2 is used for suction has been described, but the present invention is not limited to this, and the suction jig 2 can be used.
Nozzle (not shown) of a predetermined size is provided at the lower end of 4, and a vacuum pressure is applied to the nozzle by a predetermined vacuum pump (not shown) provided in the suction jig 24. Thus, the ball solder 26 in the ball solder bath 28 may be adsorbed to the nozzle and supplied to the board lands 30 one by one.

[0036]

As described above, according to the present invention, a spherical connecting medium made of a predetermined metal and having a uniform diameter is sucked by a suction means having a plurality of suction holes arranged in a predetermined pitch. By transporting the connection medium sucked by the suction means to the supply target, a stable amount of metal bumps can be supplied onto the supply target by a relatively simple process.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a metal bump supply method according to the present invention.

FIG. 2 is a plan view showing an example of a suction hole shape of a screen according to the present invention.

FIG. 3 is a partial cross-sectional view showing an embodiment of a method for supplying metal bumps according to the present invention.

FIG. 4 is a partial cross-sectional view showing an embodiment of a method for supplying metal bumps according to the present invention.

FIG. 5 is a partial cross-sectional view showing a mounting example of a conventional surface mount component.

FIG. 6 is a partial cross-sectional view of a lead using a conventional metal bump supply method.

FIG. 7 is a partial cross-sectional view showing an example of a conventional method of supplying metal bumps.

[Explanation of symbols]

1, 29 ... Printed wiring board, 2, 30 ... Board land, 3 ... Solder paste, 4, 5 ... Surface mount component,
6 ... IC lead, 7 ... Soldered, 8 ... Resin film, 9 ... Lead, 10 ... Bump forming substrate, 1
1 ... Bump, 12 ... LSI chip, 13 ... Aluminum electrode, 20 ... Solder supply device, 21 ... Driving device, 2
2 ... Laser tool, 23 ... XY direction drive arm, 24 ... Suction jig, 25 ... Screen, 26 ...
Ball solder, 27 ... Suction hole, 28 ... Ball solder bath, 31 ... Flux.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location H01L 21/321 (72) Inventor Tomoya Kiga 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation In the company

Claims (4)

[Claims] 1. A method of supplying a metal bump as a connection medium made of a predetermined metal on a supply target, comprising: forming a spherical connection medium made of a predetermined metal and having a uniform diameter in a predetermined pitch. A method of supplying metal bumps, characterized in that the connection medium, which is adsorbed by an adsorbing means having a plurality of suction holes, and is adsorbed by the adsorbing means is conveyed to the supply target. 2. The method of supplying metal bumps according to claim 1, wherein the connection medium is made of solder. 3. A metal bump supply device for supplying a metal bump as a connection medium made of a predetermined metal on a supply target, wherein the connection medium is made of a predetermined metal and has a uniform spherical shape with a uniform diameter, and the connection. A device for supplying metal bumps, comprising: a suction means for sucking a medium into a plurality of suction holes arranged in a predetermined pitch, and transporting the connection medium sucked by the suction means onto the supply target. . 4. The metal bump supply device according to claim 3, wherein the connection medium is made of solder.