WO1998009487A1

WO1998009487A1 - Method and device for supplying flux

Info

Publication number: WO1998009487A1
Application number: PCT/JP1997/003038
Authority: WO
Inventors: Kenji Shimokawa; Kohei Tatsumi; Eiji Hashino
Original assignee: Nippon Steel Corporation
Priority date: 1996-08-30
Filing date: 1997-08-29
Publication date: 1998-03-05
Also published as: TW405152B

Abstract

A method and device for supplying flux by which flux (6) can be supplied appropriately to an electrode section (2) of electronic parts (1) containing a semiconductor chip and a printed circuit board. The device is provided with a discharge nozzle (10) having a means which discharges the flux (6) in drops and the flux (6) is discharged in drops from the nozzle (10) and adhered to the electrode section (2) by a required amount. The discharge nozzle (10) of another device of this invention is provided with a continuously exciting means (23) which discharges the flux (6) in a continuous jet while the means (23) excites part of the flux (6), a splitting means (21) which splits the discharged continuous jet into a uniform particle train, and an electrifying means (22) which controls the direction of the jet by electrifying the uniform particle train so as to adhere the flux (6) to the electrode section (2) by a required amount.

Description

Specification

Flux supply method and device

Technical field

The present invention relates to a flux supply method and apparatus suitable for supplying a precisely controlled desired amount of flux to electrodes of electronic components including a semiconductor chip and a printed circuit board. is there.

Background art

When joining low-melting-point metals such as hangs to the electrodes of electronic components, it is essential to supply a flux to ensure wettability. Common methods of supplying flux include screen printing and dispensing. Also, in a BGA (Ba] Grid Arrey) package using conductive balls made of a low-melting metal such as a hang, it is necessary to form bumps on the electrodes of the printed circuit board using a desired amount of flux.

In this BGA, conductive balls (solder balls) are bonded to a large number of electrodes on the printed circuit board side, and electrical connection with an external circuit or the like is made via the conductive balls. When the conductive balls are transferred and bonded to the electrode portions, a flux is applied to each electrode portion, and the conductive balls are temporarily fixed by the adhesive force of the flux.

As a specific example of a method for supplying a flux to the electrode portion in the BGA, a method disclosed in US Pat. No. 5,284,287 is conventionally known. According to this method, as shown in FIG. 5, a pick-up tool 100 for adsorbing the conductive ball 103 in the opening of the suction hole 102 connected to the vacuum source 101, and a flux bath 106 in the recess 105. Use the black plate 104 provided.

As shown in FIG. 6, the conductive ball 103 adsorbed and held by the pick-up tool 100 is immersed to a predetermined depth X of the flux bath 106, and then pulled up from the flux bath 106. . Thereby, the flux is attached to a predetermined area of the conductive ball 103. Then, the conductive ball 103 is bonded to the electrode portion of the semiconductor device substrate via the attached flux. Disclosure of the invention

With the conventional flux supply method, it has been substantially difficult to adhere a precisely controlled amount of flux to a predetermined area such as a microelectrode. For example, in the above BGA, when using a conductive ball having a small diameter of 500 μm or less, particularly 300 μm or less, it becomes difficult to control the predetermined depth X as the ball diameter decreases, and the corresponding electrode is flushed. It is not possible to control the gas precisely and supply it stably.

The present invention has been made in view of the above circumstances, and provides a flux supply method and a device capable of appropriately supplying a flux to an electrode portion of an electronic component including a semiconductor chip and a printed circuit board. Aim.

The gist of achieving the above object of the present invention will be described below.

The flux supply method of the present invention provides a method for supplying a flux to an electrode portion of an electronic component including a semiconductor chip and a printed circuit board by ejecting the flux from a discharge nozzle. A method in which a desired amount of the flux is ejected from the ejection nozzle capable of ejecting the flux in the form of droplets to adhere to the electrode portion.

Further, in the flux supply method of the present invention, a part of the flux filled in the discharge nozzle is heated and expanded, and the flux is dropped from the discharge nozzle by the pressure due to the thermal expansion. And discharge it in the desired This is a method of attaching flux.

Further, in the flux supply method of the present invention, a part of the flux filled in the discharge nozzle is vibrated, and the flux is discharged in a droplet form from the discharge nozzle by the pressure generated by the vibration. This is a method of attaching a desired amount of flux to the electrode portion.

Further, another flux supply method according to the present invention provides a method of injecting a flux from a discharge nozzle to form a flux on an electrode portion of an electronic component including a semiconductor chip and a printed circuit board. A method for supplying a flux, in which a part of the flux filled in the discharge nozzle is vibrated and discharged as a continuous jet, and the discharged continuous jet is formed into a uniform particle row. The method is characterized in that a desired amount of the above-mentioned flux is attached to the electrode by controlling the jet direction by splitting and charging the uniform particles.

A flux supply device according to the present invention is a device for supplying a flux to an electrode portion of an electronic component including a semiconductor chip and a printed circuit board, wherein the flux is formed into droplets. The device is provided with a discharge nozzle having a means capable of discharging by spraying, and ejects a droplet-like flux from the discharge nozzle to attach a desired amount to the electrode portion.

Further, the flux supply device of the present invention is a device in which the discharge nozzle has a heating means capable of heating and expanding a part of the filled flux to form a droplet to discharge.

Furthermore, the flux supply device of the present invention is a device in which the discharge nozzle has a vibrating means capable of vibrating a part of the filled frattas to discharge in a droplet form. is there.

Further, another flux supply device of the present invention ejects a flux from a discharge nozzle to apply the flux to an electrode portion of an electronic component including a semiconductor chip and a printed circuit board. A device for supplying a flux, the discharge nozzle vibrating a part of the filled flux and An electrode unit comprising: a continuous vibrating means for discharging the continuous jet as a continuous jet; a splitting means for splitting the discharged continuous jet into a uniform particle row; and a charging means for charging the uniform particles to control the jet direction. This is a device that attaches a desired amount of flux to the surface.

According to the present invention, a flux is ejected from a discharge nozzle and supplied to an electrode portion of an electronic component including a semiconductor chip and a printed circuit board. In this case, a part of the flux filled in the discharge nozzle is heated or expanded or vibrated, and the pressure generated at this time causes the flux to be discharged from the discharge nozzle as droplets. . The amount of flux discharged from the discharge nozzle can be finely controlled, whereby a desired amount of flux can be appropriately attached to the electrode portion. By supplying an appropriate amount of flux to the electrodes in this manner, even small-diameter conductive balls can be properly applied to the electrodes of electronic components, including semiconductor chips and printed circuit boards. Can be transcribed. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view showing a schematic configuration of a flux supply device according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a flash supply method in the embodiment of the present invention in the order of steps (A) to (E).

FIG. 3 is a partial cross-sectional view showing a main part configuration of a flux supply device configured using a piezoelectric element according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a schematic configuration of an apparatus according to another flux supply method in the embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a schematic configuration of a conventional flux supply device.

Fig. 6 is a partial cross-sectional view showing the main configuration of a conventional flux supply device. It is. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of a flux supply method and apparatus according to the present invention will be described with reference to FIGS.

FIG. 1 shows a schematic configuration of a flux supply device in this embodiment. In this embodiment, it is assumed that a flux is supplied to the electrode section 2 of the electronic component 1 for forming a BGA package or the like. The electronic component is specifically a semiconductor chip or a printed circuit board. The electrode portions 2 are set on the upper surface of the electronic component 1 in a predetermined arrangement pattern and pitch, as shown by the dashed line in the illustrated example. Further, the electronic component 1 is placed and fixed on the transport conveyor 3 so as to be sent at a predetermined speed.

At a predetermined position above the conveyor 3, a flux supply head 4 is supported so as to be movable in the width direction W of the conveyor 3. The flux supply head 4 is provided with a discharge nozzle configured to discharge the flux 6 filled by the flux supply source 5 as described later. I have. The flux supply head 4 is also driven in the width direction W by a head drive unit 7, and its position is detected by a sensor (not shown). The control unit 8 controls the position of the flux supply head 4 via the head drive unit 7 and controls the discharge nozzle in the flux supply head 4. Here, FIG. 2 shows, in principle, a configuration example of the discharge nozzle 10 built in the flux supply head 4. In the discharge nozzle 10, the nozzle body 11 is filled with the flux 6 from the flux supply source 5, and the flux 6 is dripped from the opening 11 a at the tip. And discharge . The nozzle body 11 is attached to the flux supply head 4 such that the opening 11a of the nozzle body 11 faces downward. A heater 12 as a heating means for heating and expanding a part of the filled flux 6 is provided at an appropriate position of the nozzle body 11. The heater 12 is driven and controlled by the control unit 8 <, and generates heat instantaneously, thereby vaporizing some of the components of the flux 6 to generate bubbles.

By the way, in this embodiment, flux 6 having a relatively low viscosity is used. In other words, the flux 6 used is diluted with a predetermined solvent, and the viscosity of the flux 6 is increased after the flux 6 is attached to the electrode portion 2 of the electronic component 1 as described later. By using the low-viscosity flux 6 as described above, the discharge can be easily performed from the discharge nozzle 10, and the discharge amount and the like can be accurately controlled. For example, as the flux 6, a rosin-based flux and an activating agent-introduced gin-based flux can be used.

Now, when the flux 6 is supplied to the electrode section 2 of the electronic component 1, the electronic component 1 and the flux supply head 4 are aligned, and the heater 12 generates heat. Then, first, the flux 6 around the heater 12 is heated and expanded as shown in FIG. 2 (A), and small bubbles 13 are generated. These bubbles 13 merge with each other as shown in FIG. 2 (B) and grow by adiabatic expansion, whereby the flux 6 is pushed out from the opening 11a of the nozzle body 11 (FIG. 2 (C)). ). When the air bubbles 13 that have been heated by the surrounding flux 6 contract as shown in FIG. 2 (D), they disappear as shown in FIG. 2 (E) when they disappear, as shown in FIG. 2 (E). Lux 6a is discharged.

The droplet-like flux 6a discharged from the opening 11a in this manner is jetted toward the electrode section 2 of the electronic component substrate 1 as shown in FIG. A quantity of flux 6 can be deposited. After the flux 6 adheres to the electrode section 2, for example, by drying The solvent in the flux 6 may be volatilized to increase the viscosity of the adhered flux 6. By adjusting the viscosity of the flux 6 in this way, it is possible to obtain an optimum adhesive force when a conductive ball (solder ball) is transferred and arranged on the electrode portion 2. Incidentally, the flux 6 having a diameter of 5 to 100 zm (diameter) can be supplied to the electrode portion 2 by one ejection from the ejection nozzle 10.

As described above, according to this embodiment, the flux 6 is ejected from the discharge nozzle 10 and supplied to the electrode unit 2 of the electronic component substrate 1. In this case, a part of the flux 6 charged in the discharge nozzle 10 is heated and expanded by the heater 12, and the pressure generated at this time causes the flux 6 to be released from the discharge nozzle 10. Discharge in the form of drops. The discharge amount of the flux 6 from the discharge nozzle 10 can be finely controlled by driving and controlling the heater 12 by the control unit 8, whereby the desired amount can be applied to the electrode unit 2 of the electronic component substrate 1. Flux 6 can be adhered properly.

In addition, in the above-described discharge nozzle 10, a piezoelectric element as a vibration means for vibrating the filled flux 6 is provided in an appropriate place of the nozzle body 11 instead of the heater 12. Can be. The schematic configuration in this case is, for example, as shown in FIG. 3, in which a cylindrical piezoelectric element 14 is mounted inside (an inner peripheral wall) of a cylindrical nozzle body 11. In this case, a plurality of small piezoelectric elements 14 ′ may be arranged in line along the inner peripheral wall of the nozzle body 11 and arranged in an annular shape. The driving of the piezoelectric element 14 is controlled by the control unit 8, and the piezoelectric element 14 vibrates toward the center of the nozzle body 11 so as to reduce the nozzle diameter. The piezoelectric element 14 (14 ′) can also change the internal pressure of the flux 6 in the nozzle body 11, thereby discharging the flux 6 in a droplet form. Even when the piezoelectric element 14 (14 ') is used, a desired amount of flux can be adhered to the electrode portion 2 of the electronic component substrate 1. Fig. 4 shows another example of the configuration of the flux supply head 4 in principle. Is shown. In this example, the flux 6 in the discharge nozzle 20 is vibrated and discharged as a continuous jet. By controlling the jet direction by charging, a desired amount of flux is attached to the electrode section 2 of the electronic component substrate 1.

In FIG. 4, the flux supply device splits into a uniform nozzle and a discharge nozzle 20 configured to excite the flux 6 and discharge the continuous jet 6b. Means for charging the flux 21 and deflecting means 22 for controlling the jet direction of the charged flux particles 6c are provided. In this example, an exciter composed of a piezo oscillator 23 is attached to the discharge nozzle 20, and the exciter splits spontaneously by this excitation action. A knife edge 24 is disposed immediately after the deflecting means 22, so that only the uncharged flux particles 6d travel straight toward the electrode section 2 of the electronic component substrate 1. I have.

Also in this example, the flux 6 used is diluted with a predetermined solvent. The flux 6 is pressurized to, for example, about 3 to 4 MPa, and is discharged as a continuous jet 6 b having an initial velocity of about 50 m / sec from a discharge nozzle 20 having an orifice diameter of 10 μm. . Next, the continuous jet 6 b splits into a uniform row of particles at a constant spontaneous particle frequency due to the effect of surface tension.

This division into flux particles is performed in synchronization with the excitation of the piezo oscillator 23. The particle array of flux 6 is binary-controlled depending on whether or not it is attached to the electrode section 2 of the electronic component substrate 1. That is, the amount of the flux to be attached to the electrode section 2 is set in advance, and the splitting means 21 generates a control signal based on the amount of the flux. The quantitative relationship between the charged flux particles 6c and the non-charged flux particles 6d is controlled by the control signal of the splitting means 21. Flux particles 6d are directed toward the electrode part 2 of the electronic component substrate 1. And go straight.

As described above, the continuous jet 6b ejected from the ejection nozzle 20 is divided into uniform particle rows, and the flux particles are charged to control the jet direction, whereby the electrode portion of the electronic component substrate 1 is formed. 2. A desired amount of flux can be attached to 2. Incidentally, the flux 6 of 5 to 100 m (diameter) can be supplied to the electrode portion 2 by one discharge from the discharge nozzle 20.

Although the above embodiments have been described based on specific illustrated examples and the like, the present invention is not limited to those cases, and can be appropriately changed and the like within the scope of the present invention. For example, the present invention is effective for conductive balls having a small diameter of 500 m or less, particularly 300 / m or less, but can be similarly applied to balls of 500 m or more. Of course. Further, the flux supply head 4 may be provided with a plurality of discharge nozzles, so that the flux supply efficiency can be further improved. Furthermore, a plurality of ejection nozzles are installed, for example, so that flux can be supplied at high speed in BGA frame units (4 to 8 units, connected in a strip shape). It can be applied to the specification. Industrial applicability

As described above, according to the present invention, by discharging the flux from the discharge nozzle in the form of droplets, it is possible to form the flux on the electrode part of the electronic component including the semiconductor chip and the printed circuit board. Amount of flux can be adhered properly. By appropriately supplying an appropriate amount of flux to the fine area of the electrode in this way, even a BGA package using a small-diameter solder ball of 500 mm or less, especially 300 mm or less, can be efficiently used. To be able to produce well and to guarantee high joint reliability It has the advantage that it can be done.

Claims

The scope of the claims

1. A method for supplying a flux to an electrode part of an electronic component including a semiconductor chip and a printed circuit board by injecting a flux from a discharge nozzle,

A flux in which droplets of the flux are ejected from the discharge nozzle capable of discharging the flux in the form of drops to adhere to the electrode portion in a desired amount. Supply method.

2. Heating and expanding a part of the flux filled in the discharge nozzle, and discharging the flux in a droplet form from the discharge nozzle by the pressure due to the heat expansion; The method according to claim 1, wherein a desired amount of the flux is attached to the electrode unit.

3. A part of the flux filled in the discharge nozzle is vibrated, and the flux is discharged from the discharge nozzle as droplets by the pressure generated by the vibration. 2. The method according to claim 1, wherein a desired amount of the flux is applied to the electrode portion.

4. A method for injecting a flux from a discharge nozzle to supply the flux to an electrode part of an electronic component including a semiconductor chip and a printed circuit board,

When a part of the flux filled in the discharge nozzle is vibrated, it is discharged as a continuous jet at the same time, and the discharged continuous jet is split into a uniform particle row, and the uniform particles are separated. A flux supply method characterized in that a desired amount of the flux is attached to the electrode portion by controlling the jet direction by charging.

5. An apparatus for supplying a flux to the electrodes of an electronic component including a semiconductor chip and a printed circuit board,

Discharge nozzle having means for discharging the flux in a droplet form A flux supply device, comprising: ejecting a droplet-like flux from the discharge nozzle to attach a desired amount of the flux to the electrode portion.

6. The apparatus according to claim 5, wherein the discharge nozzle has a heating means capable of heating and expanding a part of the filled flux to discharge it in the form of droplets.

7. The discharge nozzle according to claim 5, wherein the discharge nozzle has a vibrating means capable of vibrating a part of the filled flux to form a droplet to discharge. apparatus.

8. A device for injecting a flux from a discharge nozzle to supply the flux to an electrode part of an electronic component including a semiconductor chip and a printed circuit board,

The discharge nozzle includes a continuous vibrating unit that vibrates a part of the filled flux and discharges the continuous jet as a continuous jet, and a split that splits the discharged continuous jet into a uniform particle row. And a charging means for charging the uniform particles to control a jet direction, and adhering a desired amount of the flux to the electrode portion.