JP2002320894A - Discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge device which is capable of printing fine patterns of liquids of solder, electrode paste or the like having a high viscosity. SOLUTION: A discharge nozzle 11 of the discharge device including the discharge nozzle 11 for discharging the discharge material from a nozzle hole 11a and a discharge material introducing section 13 for supplying the discharge material to the discharge nozzle 11 consists of a piezoelectric material and the outer peripheral surface of the discharge nozzle 11 is provided with an even number of >=4 pieces of drive electrodes 15 at prescribed intervals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge device, and more particularly to a method for surface-mounting an IC chip or a small electronic component on a substrate or the like, or writing a circuit pattern for surface mounting.
The present invention relates to a discharge device that discharges and prints solder or electrode paste having high viscosity in a fine pattern.

[0002]

2. Description of the Related Art Conventionally, for example, in order to surface mount an IC chip or a small electronic component on a substrate or the like, or to write a circuit pattern for surface mounting, to discharge and print solder or electrode paste in a fine pattern. A discharge device is used.

A discharge device for discharging a high-viscosity material such as solder or electrode paste discharges a desired amount at a desired speed by overcoming the viscosity of solder or electrode paste and friction with the inner wall surface of a nozzle hole. Since it is necessary to apply high pressure to the solder etc. in the nozzle hole and reduce the viscosity of the solder etc. by applying a high temperature, the viscosity and friction can be reduced by changing the characteristics of the ejection material. I was

Further, the inner wall surface of the nozzle hole is machined so as to have a surface as smooth as possible to reduce friction. In addition, a technique such as controlling the discharge amount of solder and the like with a screw-type pressurizing device, 0.5m
This enables pattern printing with a diameter of about m.

[0005]

In recent years, IC chips and small electronic components have become smaller. Solder for surface mounting such small IC chips and small electronic components on a substrate or the like, or surface mounting. Circuit patterns are becoming finer and smaller and cannot be handled by conventional ejection devices.

[0006] That is, in the conventional discharge device, in terms of discharging a highly viscous material such as solder or electrode paste, the friction of the inner wall surface of the nozzle hole causes the discharge diameter to be maintained while maintaining a desired speed and coating performance. Can be reduced to several hundred microns
The diameter of m was almost at its limit. It was very difficult to print thin lines or mounting pads having a width smaller than this.

[0007] For example, Japanese Patent Application Laid-Open No. 2000-120983 discloses a discharge device including a discharge nozzle and a vibrating section composed of a piezoelectric element that shakes off the liquid remaining at the tip of the discharge nozzle by vibration. I have. In this discharge device, the vibration unit can be excited in the x and y directions to vibrate, the entire tip of the discharge nozzle can be vibrated in the x and y directions, and the liquid remaining at the tip of the discharge nozzle can be shaken off by vibration. Since the entire tip of the discharge nozzle vibrates, a fine pattern required in recent years cannot be formed.

An object of the present invention is to provide a discharge device capable of printing a liquid such as solder or electrode paste having a high viscosity in a fine pattern.

[0009]

A discharge apparatus according to the present invention comprises a discharge nozzle for discharging a discharge material from a nozzle hole, and a discharge material introduction unit for supplying the discharge material to the discharge nozzle. The discharge nozzle is made of a piezoelectric material, and four or more even-numbered drive electrodes are provided at predetermined intervals on the outer peripheral surface of the discharge nozzle.

In such a discharge device, the piezoelectric material is polarized between the adjacent drive electrodes, and a voltage having a different polarity is applied to the adjacent drive electrodes at a predetermined drive frequency, so that the discharge nozzles are driven. The inner wall surface of the nozzle hole can be caused to vibrate in a standing wave such as a high-frequency elliptical shape.

The resistance at the time of discharge due to friction with the inner wall surface of the nozzle hole increases as the discharge diameter decreases. For this reason, the limit of discharging a high-viscosity material such as solder or electrode paste is about several hundred μm. In order to reduce this resistance, it is necessary to reduce the friction at the interface between the inner wall surface and the highly viscous material.

When high-frequency vibration due to piezoelectric vibration is generated on the inner wall surface of the nozzle hole, a boundary layer of a thin flow at the interface between the highly viscous material causing friction and the inner wall surface of the nozzle hole can be peeled off from the inner wall surface. By virtue of the thixotropic properties of the high viscosity material, the viscosity of the high viscosity material near the inner wall surface can be dramatically reduced. Accordingly, it is possible to print a fine wiring or a mounting pad with a diameter of about several tens of μm even with a discharge material such as a solder or an electrode paste having a high viscosity, without performing a discharge control at a high pressure or a high temperature.

Further, by controlling the driving frequency,
Standing wave vibration can be generated on the inner wall surface of the nozzle hole, and a vibration mode that does not change the outer shape of the discharge nozzle can be selected.For example, even in a depression almost the size of the outer shape of the discharge nozzle, Solder or electrode paste can be applied without affecting vibration or the like.

Further, the present invention provides a discharge apparatus comprising: a discharge nozzle for discharging a discharge material from a nozzle hole; and a discharge material introduction unit for supplying the discharge material to the discharge nozzle. The introduction portion is made of a piezoelectric material, and four or more even-numbered drive electrodes are provided at predetermined intervals on the outer peripheral surface of the discharge material introduction portion.

In such a discharge device, the piezoelectric material is polarized between the adjacent drive electrodes, and a voltage having a different polarity is applied to the adjacent drive electrodes at a predetermined drive frequency, so that the discharge nozzles are driven. The inner wall surface of the nozzle hole can be made to vibrate in a standing wave such as a high-frequency elliptical shape, so that even a high-viscosity discharge material such as solder or electrode paste can have a fine wiring or a mounting pad with a diameter of about several tens of μm. Can be printed.

Further, by controlling the driving frequency,
Standing wave vibration can be generated on the inner wall surface of the nozzle hole, and a vibration mode that does not change the outer shape of the discharge nozzle can be selected.For example, even in a depression almost the size of the outer shape of the discharge nozzle, Solder or electrode paste can be applied without affecting vibration or the like.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a discharge device according to the present invention comprises a cylindrical discharge nozzle 11 and a discharge nozzle 11 having a cylindrical shape.
And a discharge material introduction section 13 formed at one end of the discharge material. Although not shown, a tube or the like for supplying a discharge material to the discharge material introduction unit 13 is connected to the discharge material introduction unit 13.

A nozzle hole 11a for discharging the discharge material is formed in the discharge nozzle 11, and a supply hole for supplying the discharge material to the discharge nozzle 11 is formed in the discharge material introduction portion 13.
The nozzle hole 11a communicates with the supply hole. Nozzle hole 1
The diameter of 1a is about several tens of μm, and the outer diameter of the discharge nozzle 11 is about 100 μm. The diameter of the nozzle hole 11a may be large, but is preferably 100 μm or less from the viewpoint of forming a fine pattern.

In the present invention, the discharge nozzle 11 is made of a piezoelectric material, and its outer peripheral surface has a rectangular drive electrode 15 formed in the axial direction as shown in FIGS. Are formed annularly at predetermined intervals in the width direction. More specifically, the drive electrode 15
Around the outer surface of the cylindrical discharge nozzle 11, it is formed at a pitch of 90 degrees, and its shape, thickness, and material are the same. That is, the drive electrodes 15 are given symmetrically to the left and right and up and down, and the input potentials are given so that the adjacent drive electrodes have opposite signs. No electrode is formed on the inner wall surface of the nozzle hole 11a.

The drive electrodes 15 are connected to extraction electrodes (not shown) formed on the surface of the discharge material introduction section 13, and these extraction electrodes are connected to a power supply in the discharge device that generates an input signal. And each drive electrode 15 is connected via an extraction electrode.
A voltage having a desired polarity can be applied at a desired frequency.

The discharge nozzle 11 is connected to the adjacent drive electrode 15.
It is formed so as to apply a voltage of a different sign to the adjacent driving electrode 15 via the power supply device and the extraction electrode.

In the discharge device configured as described above, the driving frequency of the voltage applied to each driving electrode is changed by the power supply device to select the driving frequency for vibrating the inner wall surface of the nozzle hole 11a. Can be.

Further, by controlling the driving frequency, the inner wall surface of the nozzle hole 11a can be vibrated, and a vibration mode in which the outer shape of the discharge nozzle 11 is not changed can be achieved. FIG.
FIG. 1B is a conceptual diagram of the discharge nozzle 11 of FIG. 1B vibrating in such a vibration mode.
While the inner wall surface of the nozzle causes standing wave vibration such as an elliptical shape, the outer surface of the discharge nozzle 11 is in a mode of vibrating only along the outer surface (on the circumference). In addition, black circle (●)
Indicates a fixed point, at which a drive electrode is formed.

The present inventors conducted FEM analysis on the structure shown in FIG. 1B and examined what kind of vibration mode occurs depending on the driving frequency. As a result, the resonance mode corresponding to FIG. Confirmed that it exists. FIG. 3 shows the FE
4 shows a resonance mode obtained by M analysis. From FIG. 3, it can be seen that the outer periphery vibrates only along the circumference, and the inner periphery vibrates only on the inner wall surface due to a standing wave such as an ellipse.

Here, the outer shape of the discharge nozzle 11 is 1
00 μm, the inner diameter was 40 μm, and the piezoelectric material was PZT. In this case, it was confirmed that the vibration mode appeared at about 63 MHz.

Therefore, according to the discharge apparatus of the present invention, even if the discharge nozzle 11 comes into contact with a component already mounted on the substrate or a convex portion of the mounting substrate having irregularities, the outer shape of the discharge nozzle 11 Is a vibration mode that does not change, so that vibrations that hinder the structure around the discharge nozzle 11 are not given, and only the inner wall surface of the nozzle hole 11a vibrates so as to deform the space. Discharges fine electrode patterns and mounting pads on a substrate with irregular shapes,
Can be printed. For example, a mounting pattern or the like can be applied to a concave portion having a width of about 100 μm.

That is, by alternately inputting high-frequency electric signals having different signs to the drive electrodes 15 attached to the outer surface of the discharge nozzle 11, piezoelectric vibration is excited, and high-frequency constant is applied to the inner wall surface of the nozzle hole 11a. A standing wave oscillation appears. In particular, by selecting an appropriate frequency, select a vibration mode in which the inner wall surface oscillates in a standing wave such as an elliptical shape, and the outer surface oscillates on the circumference while maintaining a circular shape, as shown in FIG. can do. By selecting this vibration, it is possible to apply the solder or the electrode paste without affecting the surroundings even in a recess having a size almost the same as the outer shape of the discharge nozzle 11.

Further, when high frequency vibration due to piezoelectric vibration is generated on the inner wall surface of the nozzle hole 11a, a thin flow boundary layer at the interface between the highly viscous material causing friction and the inner wall surface of the nozzle hole 11a is peeled off from the inner wall surface. The viscosity of the highly viscous material in the vicinity of the inner wall surface can be drastically reduced due to the thixotropic property of the highly viscous material. As a result, even if the ejection material such as solder or electrode paste having a high viscosity is used, it can be driven by several tens of μm without being driven at high pressure or high temperature.
Fine wiring and mounting pads can be printed with a diameter of the order of magnitude.

When there is no fear that the nearby fine uneven pattern will be affected by vibration, the vibration mode shown in FIG. 2 does not need to be used, and a mode in which the vibration of the inner wall surface is large is sufficient. is there.

FIG. 4 shows another discharge device of the present invention. In this discharge device, a drive electrode 25 is formed not on the discharge nozzle 11 but on the discharge material introduction portion 13.

That is, in this discharge device, the discharge nozzle 11
Is connected to a discharge material introduction portion 13 having a conical shape. The discharge material introduction portion 13 is made of a piezoelectric material. The four drive electrodes 25 are arranged around the discharge material introduction portion 13.
Are formed.

In such a discharge device, the discharge nozzle 11
On the surface of the discharge material introduction portion 13 made of a piezoelectric material away from
By forming a drive electrode 25 and inputting an electrical signal having a frequency corresponding to a desired vibration mode of the 25 discharge nozzle 11 to the drive electrode, the nozzle hole 11 a is not directly attached to the outer surface of the discharge nozzle 11. The inner wall surface can be vibrated, and desired piezoelectric vibration can be excited on the inner wall surface of the nozzle hole 11a of the discharge nozzle 11 formed at the tip of the discharge material introduction portion 13. That is, a vibration mode in which only the inner wall surface of the nozzle hole 11a vibrates can be realized by utilizing the incomplete energy confinement effect of the resonance mode.

In this case, since the most vibrating part is separated from the electrode attachment position and the peak of the input impedance is expected to be reduced depending on the position of the driving electrode, the high-frequency signal generator in the discharge device is provided with a desired high-frequency signal. It is necessary to design to generate the frequency with high accuracy. In the discharge device shown in FIG. 4, the discharge nozzle 11 does not need to be made of a piezoelectric material, but is made of a metal material or the like that is advantageous for manufacturing a cylindrical shape having a small diameter and that is less likely to be worn by a highly viscous material. You can choose.

As shown in FIG. 4 and FIG. 5, the position where the drive electrode is stretched is the outer peripheral surface of the discharge material introduction portion 13 where the discharge nozzle 11 is mounted. If the discharge material introduction portion 13 is made of a piezoelectric material, piezoelectric vibration is excited at this portion, and the vibration is transmitted to the discharge nozzle 11. By providing an input signal of an appropriate frequency, the discharge nozzle 11 causes a desired resonance state, thereby enabling discharge of a target high-viscosity fluid.

If there is no concern that the fine irregular pattern near the discharge point on the mounting substrate will be affected by vibration, the vibration mode shown in FIG. 2 does not need to be used, and the vibration mode of the inner wall may be large. Is enough. In this case, in order to prevent the center axis of the ejection nozzle from vibrating and causing blurring or the like in the ejected print pattern, FIG.
As shown in (b), it is necessary to stretch the electrode so as to maintain the left-right and up-down symmetry of the electrode position. At this time, the number of electrodes may be large, but when the number of electrodes exceeds eight, even in the case of basic vibration, the vibration amplitude is reduced, so that the desired characteristics may be degraded.

[0036]

According to the discharge apparatus of the present invention, since an even number of four or more drive electrodes are provided on the outer peripheral surface of the discharge nozzle at a predetermined interval, the piezoelectric material is polarized between the adjacent drive electrodes. By applying voltages of different polarities to adjacent drive electrodes at a predetermined drive frequency, the inner wall surface of the nozzle hole of the discharge nozzle can be vibrated by a standing wave such as a high-frequency elliptical shape. Even with a viscous material such as solder or electrode paste, it is possible to print fine wiring and mounting pads with a diameter of about several tens of μm without driving at high pressure or high temperature.

Further, by controlling the driving frequency,
Standing wave vibration can be generated on the inner wall surface of the nozzle hole, and a vibration mode that does not change the outer shape of the discharge nozzle can be selected.For example, even in a depression almost the size of the outer shape of the discharge nozzle, Solder or electrode paste can be applied without affecting vibration or the like.

[Brief description of the drawings]

FIGS. 1A and 1B show a discharge device of the present invention, wherein FIG. 1A is a perspective view and FIG. 1B is a sectional view of a discharge nozzle.

FIG. 2 is an explanatory diagram showing a piezoelectric vibration mode generated in a discharge nozzle.

FIG. 3 is a diagram showing a simulation result for explaining a vibration mode.

FIG. 4 is a cross-sectional view showing another ejection device of the present invention.

FIG. 5 is a sectional view showing still another ejection device of the present invention.

[Explanation of symbols]

 11: Discharge nozzle 11a: Nozzle hole 13: Discharge material introduction part 15, 25: Drive electrode

Claims (4)

[Claims] 1. A discharge device comprising: a discharge nozzle for discharging a discharge material from a nozzle hole; and a discharge material introduction unit for supplying the discharge material to the discharge nozzle, wherein the discharge nozzle is made of a piezoelectric material, An ejection apparatus, comprising: an outer peripheral surface of an ejection nozzle provided with an even number of four or more drive electrodes at predetermined intervals. 2. A discharge apparatus comprising: a discharge nozzle for discharging a discharge material from a nozzle hole; and a discharge material introduction unit for supplying the discharge material to the discharge nozzle, wherein the discharge material introduction unit is made of a piezoelectric material. A discharge device, wherein four or more even-numbered drive electrodes are provided at predetermined intervals on the outer peripheral surface of the discharge material introduction part. 3. The discharge device according to claim 1, wherein the piezoelectric material is polarized between adjacent drive electrodes. 4. The discharge device according to claim 1, wherein an inner wall surface of the nozzle hole of the discharge nozzle vibrates.