JPH09252004A - Bump electrode forming device - Google Patents

Abstract

(57) Abstract: A ball (5a) is formed at the tip of a wire (5) by electric discharge, and the ball (5a) is ultrasonically connected to the electrode formation planned portion of the substrate (2) at the lower end of the capillary (4) to form a bump electrode (9). In the device, the non-oxidizing gas is supplied to the discharge region so that the oxide film is not formed on the ball 5a, but there is a problem that the consumption amount of this gas is large. SOLUTION: The device of the present invention is a gas discharge port 1 connected to the tip of a pipe 17 for supplying a non-oxidizing gas to a discharge region.
Since 8a is placed as close as possible to the capillary 4, the discharge region can be shielded from the outside air by a small amount of gas, and a good electrode can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field relating to an apparatus for forming bump electrodes (projection electrodes) on predetermined portions of a semiconductor wafer on which electrodes are to be formed or on a conductive pattern formed on an insulating substrate.

[0002]

2. Description of the Related Art In a TAB type semiconductor device, a conductive foil is generally laminated on an insulating tape having a through hole, and the conductive foil is etched to form a conductive pattern including inner leads extending into the through hole. Using the TAB tape prepared above, a semiconductor pellet having a bump electrode is placed in the through hole of the TAB tape, the electrode and the free end of the inner lead are polymerized, and the polymerized portion is electrically connected by thermocompression bonding. Manufactured.
A semiconductor pellet used in this semiconductor device is formed by aligning a large number of semiconductor circuit elements of the same pattern in one semiconductor wafer, and terminals connected to internal circuit elements are formed along the periphery of the semiconductor circuit element forming region. The semiconductor wafer is manufactured by cutting the semiconductor wafer from a portion adjacent to the element forming region, forming bump electrodes on the terminal portions. This bump electrode is generally formed collectively by plating or vapor deposition, but a metal ball is formed at the tip of the wire inserted in the capillary, and this metal ball is formed at the lower end of the capillary to which ultrasonic vibration is applied. There is also known a method in which bump electrodes are formed one by one by pressing a predetermined portion to complete the connection and then cutting the wire. (For example, JP-A-62-1
15748, JP-A-3-229422, JP-A-6-232132, JP-A-7-37930 (Prior Art 1), JP-A-7-37889 (Prior Art 2), etc.) This wire An example of the bump electrode forming apparatus using the above will be described with reference to FIGS. 7 and 8. In the figure, reference numeral 1 is a support table for positioning and supporting a semiconductor wafer 2 having a bump electrode formation planned portion (not shown) on its upper surface, which is moved by a predetermined pitch in a horizontal plane by an XY table (not shown) and bump electrodes are provided. The planned formation part is positioned at a predetermined position. A heating means (not shown) is embedded in the inside of the support table 1 to heat the semiconductor wafer 2 to a predetermined temperature. Reference numeral 3 denotes a horn to which ultrasonic vibration is applied, and although not shown, an intermediate portion is rotatably supported and swings around this rotation axis. Four
Is a capillary made of a hard material such as an artificial gemstone such as an artificial ruby or a ceramic, and is fixed to one end of the horn 3 with its axis arranged in the up-down direction, and the capillary 4 is vertically moved by the swinging of the horn 3. Reference numeral 5 denotes a bump electrode material, for example, a wire made of a metal such as gold or copper or an alloy such as lead-tin or silver-tin. The wire 5 is fed from a spool (not shown) and inserted into the capillary 4 so that the end of the capillary 4 It is projected from the bottom edge. The horn 3 is movable in its axial direction, horizontally moves to the side of the capillary 4 and moves forward, and swings so as to move the capillary 4 up and down in the retracted position, and the electrode formation planned portion of the semiconductor wafer 2 is positioned in the lower position. The position of the support table 1 is controlled so that Reference numeral 6 is a gas supply pipe to which a reducing hydrogen gas, an inert argon gas, a nitrogen gas or a non-oxidizing gas which is a mixture thereof is supplied, and the tip portion extends horizontally and the gas discharge port 6a is at the forward position. The capillaries 4 are arranged so as to face the lower end side of the capillaries 4. 7
Indicates a discharge electrode horizontally projected from the lower surface of the outer periphery of the opening end 6a of the gas supply pipe 6. The tip of the gas supply pipe 6 and the discharge electrode 7 are fixed to an insulating block 8 which is fixedly arranged independently of the support table 1 and the horn 3.
The operation of this device will be described below. First, the horn 3 is moved forward to position the wire 5 inserted into the capillary 4 and protruding from the lower end thereof on the discharge electrode 7, and a high voltage is applied between the wire 5 and the discharge electrode 7 to cause discharge. A metal or alloy molten ball 5a is formed at the tip. next,
The horn 3 is retracted, the capillary 4 is lowered, and X is preset.
The ball 5a is arranged on the electrode formation planned portion of the semiconductor wafer 2 positioned by the Y table, and the ball 5a is pressed and connected at the lower end of the capillary 4 while applying ultrasonic vibration, and the bump electrode 9 is formed. At this time, the semiconductor wafer 2
Since the ball is heated, the ball 5a to be the electrode 9 is firmly bonded to the electrode formation planned portion. Then, the wire 5 is fixed to the capillary 4 and the horn 3 is raised to cut the wire 5 near the bump electrode (not shown), and the tip end thereof is slightly projected from the tip end of the capillary 4. In this state, the semiconductor wafer 2 is moved by a predetermined pitch by the XY table to position the next bump electrode formation planned portion at a position below the capillary 4 and return to the state of FIG. After that, the bump electrode 9 can be sequentially formed in the electrode formation planned portion by repeating the above operation. In this device, since the diameter of the bump electrode is determined by the diameter of the wire 5, it is possible to secure a sufficient height and form the electrode 9 having a predetermined diameter.

[0003]

In the apparatus shown in FIG. 7, the diameter of the molten ball 5a is set from the diameter of the bump electrode 9, and the diameter of the molten ball 5a and the length of the wire 5 protruding from the capillary 4 are further determined from the diameter of the molten ball 5a. Is set, but wire 5
When the wire is discharged in contact with air, not only the surface of the ball 5a is oxidized by a wire other than gold but also the shape becomes defective, an oxide film is present between the electrode formation planned portion and the ball 5a, and the capillary 4 There is a problem that the pressing force becomes non-uniform due to the uneven distribution of the pressing force and the connection strength of the bump electrode 9 is lowered. In order to solve such problems, it is important to form a ball that is close to a true sphere without an oxide film on the surface.
In order to form a good ball, it was necessary to fill the region completely containing the wire 5 protruding from the capillary 4 with a non-oxidizing gas. On the other hand, the non-oxidizing gas discharged from the pipe 6 entrains air when a turbulent flow is generated. Therefore, it is necessary to control the supply of the gas so as not to generate the turbulent flow. It is difficult to set the optimum conditions because it depends on the diameter, the gas supply amount, the distance from the gas discharge port to the discharge area, etc., and the range is extremely narrow. Therefore, in consideration of the entrainment of air due to the turbulent flow, the opening diameter of the gas supply pipe 6 is set sufficiently larger than the protruding length of the wire so that the turbulent flow area deviates from the discharge area. There was a problem that the gas consumption was increased and the utility cost was high because it had to be increased. It is also possible to bring the open end 6a of the gas supply pipe 6 close to the discharge region in order to reduce the gas supply amount and supply the gas free of air entrainment due to turbulence to the discharge region to form a good ball. If the gas supply pipe 6 is made of metal, even if there is no problem in the capillary 4 in a stationary state or a low speed operation state, if the gas supply pipe 6 is operated at a high speed, abnormal discharge occurs once every several times between the discharge electrode 7 and the pipe 6. When such abnormal discharge occurs, the molten ball 5a cannot be formed on the wire 5, and even if the ball can be formed, the shape may be defective. When the bump electrode is formed with a ball having a defective shape, the semiconductor pellet may be defective, so that the distance between the gas supply pipe 6 and the capillary 4 cannot be made close, and the gas consumption cannot be reduced. In addition, if the non-oxidizing gas contains hydrogen gas, if its consumption is large, it may cause an explosion due to ignition or mixing with air, so it is necessary to install a local exhaust facility, resulting in a larger facility. There was a problem. As a solution to such a problem, Prior Art 1 discloses a bump electrode forming apparatus in which an inert gas and hydrogen gas supply pipes are separately provided and hydrogen gas is supplied only during discharge. The opening diameter of the gas supply pipe still needs to be made sufficiently larger than the protruding length of the wire, and the gas consumption cannot be reduced. In addition, the lower end of the capillary 4 is positioned on the discharge electrode 7 fixedly arranged extending from the opening of the gas supply pipe 6 for supplying the non-oxidizing gas, the molten ball 5a is formed by the discharge, and then the capillary 4 is fixed. Since it is necessary to allow the ball 5a to move up and down to a position where it does not come into contact with the discharge electrode 7, the bonding work cannot be performed immediately after the ball 5a is formed, and there is a problem that high speed operation is not possible. In particular, several hundreds, such as a drive circuit device of a liquid crystal display device
It is important to shorten the time required to form electrodes in a semiconductor device that requires a single electrode, and to improve the operation time per semiconductor wafer having several tens to several hundreds of such elements significantly reduced. Was desired. Further, the temperature of the capillary 3 rises during operation due to discharge and contact with the heated wafer 2. However, when the wire 5 which is an electrode material is a low melting point alloy such as solder, a high temperature is required before bonding. When exposed to the atmosphere, it softens, ultrasonic vibrations are not effectively transmitted, and there is a problem that the connection strength with the electrode formation planned portion becomes insufficient. In order to solve such a problem, in prior art 2, a semiconductor for which a pipe for cooling a capillary is provided in addition to a gas supply pipe for the purpose of preventing oxidation of balls when forming molten balls. Manufacturing equipment is disclosed, but gas consumption is high,
The problem of high utility costs still remained.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been proposed for the purpose of solving the above problems, in which a wire made of an electrode material is inserted into a capillary which is vertically moved by application of ultrasonic vibration, and the tip of the capillary is inserted into the capillary. It is made to project from the lower end and discharged between the protruding part of this wire and the discharge electrode to form a molten ball at the tip of the wire, and this ball is at the lower end of the capillary to the electrode formation planned part on the substrate supported by the support table. In the device that presses and forms bump electrodes, the gas discharge part of the gas guide connected to the gas supply pipe is brought as close as possible to the discharge region between the wire protruding from the lower end of the capillary and the discharge electrode, and a non-oxidizing gas A bump electrode forming apparatus is provided which is characterized by being supplied. In order to bring the gas discharge part as close as possible to the lower end of the capillary, the gas supply pipe has electrical insulation and even if it comes into contact with the capillary, its effect on ultrasonic vibration is suppressed as much as possible. Connect the gas guide made of the material to be obtained. This gas guide can be constructed by winding a tape member having electrical insulation and flexibility around the outer circumference of the end of the gas supply pipe, and a tube having electrical insulation and flexibility. The member may be fitted to the end of the gas supply pipe. By using such a gas guide, the distance between the outer periphery of the lower end of the capillary and the gas discharge portion of the gas guide is 2.
It can be set within 5 mm. The gas consumption can be minimized by reducing the inner diameter of the gas guide from the axial center toward the gas discharge portion according to the diameter of the molten ball.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION A bump electrode forming apparatus according to the present invention supports a substrate having an electrode formation planned portion, a support table that is controlled to move in the XY directions, and a wire made of an electrode material is inserted to cause ultrasonic vibration. It is arranged so that it can be reciprocated in a horizontal plane that includes the applied capillary that moves up and down, and the position below the capillary. , A discharge electrode forming a molten ball at the tip of the wire,
A gas supply pipe to which a non-oxidizing gas is supplied and one end of which communicates with the gas supply pipe, and a gas discharge part of the other end is fixedly arranged with respect to the capillary shaft as close as possible to the lower end of the capillary. With a gas guide, a ball formed at the tip of the wire protruding from the lower end of the capillary is discharged by discharge in a non-oxidizing atmosphere formed by the gas guide, and ultrasonic waves are applied at the lower end of the capillary to form electrodes on the substrate. A bump electrode is formed by pressing the portion. The distance between the outer circumference of the lower end of the capillary and the gas discharge part of the gas guide is 2.5 mm.
By setting it within the range, the gas supply to the discharge region can be adjusted over a wide range without affecting the quality of the ball. The gas guide connected to the gas supply pipe is made of a material that has electrical insulation and flexibility, so that even if it comes into contact with the capillary, its influence on ultrasonic vibrations will be suppressed as much as possible. You can More specifically, a tape guide having electrical insulation and flexibility is wound around the outer circumference of the end of the gas supply pipe to form a gas guide. The flexible thin tape member retains flexibility even when wound in several layers, and does not affect ultrasonic vibration even when contacting with the capillary. Alternatively, a tubular member having electrical insulation and flexibility may be fitted to the end of the gas supply pipe to form the gas guide. By reducing the inner diameter from the axial center of the gas guide toward the gas discharge portion, the opening diameter of the gas discharge port can be arbitrarily set, and the amount of gas to be supplied can be optimally set.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the figure, the same reference numerals as those in FIG.
A duplicate description will be omitted. In the device according to the present invention, the horn 3 is capable of reciprocating in its axial direction, projects toward the capillary 4, and moves the capillary 4 up and down at that position. In the figure,
Reference numeral 10 is a discharge electrode, and the oscillating mechanism 11 causes the horn 3 to reciprocate in a horizontal plane that crosses the lower position of the capillary 4 in the forward position. In the illustrated example, the swing mechanism 11 fixes the discharge electrode 10 and a fixed block 12 fixed to a support member (not shown) connected to a base (not shown) that swingably supports the horn 3. The movable block 14 is rotatably supported on the fixed block 12 by the rotating shaft 13, and is inserted between the opposing wall surfaces of the fixed block 12 and the movable block 14, and is elastic so as to push the movable block 14 outward. It comprises a spring 15 to which a force is applied, and a magnetic attraction means 16 composed of a magnetic piece 16a for attracting the movable block 14 to the fixed block 12 in the opposite direction to the spring 15 and an electromagnet 16b. Reference numeral 17 is a gas supply pipe to which a non-oxidizing gas in which a reducing hydrogen gas and an inert argon gas are mixed is supplied, and one end side 17a is connected to a gas supply source via a gas flow rate control unit, Part is fixed independently of a support member (not shown) connected to a base (not shown) that pivotally supports the horn 3 and a support table 1 that supports the semiconductor wafer 2, and the other end 17b.
The gas discharge port 18a is opened to the side of the lower end of the capillary 4 in the raised position. This gas supply pipe 17 is
It may be made of metal or resin, but the feature of the present invention is that the other end 17b of this pipe has a flexible tubular gas guide 1
8 is connected and the gas discharge port 18a which is the opening end thereof is fixedly arranged with respect to the axis of the capillary 4 as close as possible including contact with the side wall of the capillary 4.
A material that does not affect the operation of the gas guide 18 even if it contacts the capillary 4 is selected. Specifically, a resin having electrical insulation, heat resistance, and flexibility, such as a silicone resin, is used, and the liquid is used to open the pipe 17 and the inner and outer peripheral surfaces adjacent to the open end as shown in FIG. The thin film is applied to the surface of the gas discharge port 1 to form the elastic film 19.
8a is formed. Furthermore, the thin tubular end of the gas discharge port 18a can be made into a fine fiber shape to improve flexibility. As a result, the gas discharge port 18a is arranged close to the lower end portion of the capillary 4, so that the gas discharge port 18a
The discharge region in close proximity to is completely located in the non-oxidizing gas flow and there is no entrapment of outside air in this region. The present inventor
With the wire 5 made of tin alloy and having a diameter of 40 μm protruding 1 mm from the lower end of the capillary 4, the distance between the tip and the discharge electrode 10 was set to 0.5 mm, and the gap was set to 25 mm.
A potential difference of 00 V is applied, and the gas discharge port 18 is provided in this discharge region.
With two kinds of gas guides having an inner diameter of 2 mm and 4 mm, hydrogen gas 10% and non-oxidizing gas of residual argon gas are supplied to change the distance between the capillary 4 and the gas guide 18,
It was found that there is a relationship shown in FIG. 4 between this distance d and the gas flow rate Q that can improve the state of the ball 5a. That is, when the metal gas supply pipe 17 is brought close to the capillary 4 without the gas guide 18, the distance d is 2.
If the distance is 5 mm or less, even if there is no hindrance in a stationary state or a low speed operation, when the high speed operation is performed, the discharge electrode 1 is once every several times.
0 and a pipe, an abnormal electric discharge is generated, the molten ball 5a cannot be formed on the wire 5, and even if the ball can be formed, the shape may be defective. It could not be set to 5 mm or less. Also, if the gas flow rate exceeds 10 liters per minute, the hydrogen concentration is 250 p
Since the explosion-proof detector set to pm operates and the risk of gas explosion increases, it becomes necessary to install a forced exhaust device. On the other hand, in the device of the present invention, since the gas guide 18 is connected to the gas supply pipe, the gas above the curve shown by the black circle in the figure for a pipe with a diameter of 2 mm and the curve shown with a dotted line in the figure for a pipe with a diameter of 4 mm, respectively. There is no explosion or undesired discharge in the flow rate region, the surface is not oxidized, and a well-shaped ball can be formed. It is possible to form a bump electrode with a stable shape and good connection strength continuously at high speed. did it. When the distance d exceeds 2 mm, there is no difference in the quality of the balls due to the difference in the opening diameter of the gas guide, and when the distance d is 2 mm or less, there is a slight difference, and the distance d is 0 mm, that is, the gas discharge port of the gas guide is In the state of being in contact with the capillary 4, the pipe having a diameter of 2 mm has a gas flow rate Q of 0.3 per minute.
A pipe having a diameter of 4 mm and a liter or more has a flow rate Q of 0.
Good balls were obtained at 5 liters or more. In the conventional device, the distance d is 2.5 mm to 3.1 mm, and the flow rate Q is 3.
The optimum setting area is within the illustrated hatched area in the range of 0 liter to 10 liter, preferably within the illustrated grid area where the distance d is 2.5 mm to 2.8 mm and the flow rate Q is 3 liter to 5.5 liter per minute. On the other hand, in the device of the present invention, there is no restriction on the discharge limit, and it can be set within a wide area surrounded by the indoor explosion-proof detection operation area and the curve. Especially, the gas flow rate Q is restricted to 0.3 liters per minute. Can form a good ball.
Since the gas guide 18 can be as close to the capillary 4 as possible, the discharge region can be kept in a good non-oxidizing atmosphere even if the gas flow rate Q is greatly reduced, and a good ball can be formed. . As a result, stable and stable bump electrodes can be formed at high speed, and the amount of gas used can be significantly reduced.
The utility cost can be kept low. With this device, if you set the optimum amount of gas used to form the balls, there is no risk of ignition or explosion because it will diffuse into the air under natural ventilation and will not exceed the explosion-proof limit. Is unnecessary, and the overall size of the device can be reduced. Furthermore, since the discharge position and the bonding position are the same position, it is possible to move to the bonding work immediately after forming the ball and to operate at high speed. Further, since the gas discharged from the gas guide 18 is constantly blown onto the surface of the capillary, the capillary 17 can be cooled, and even when a low melting point alloy wire is used as an electrode material, softening due to temperature rise of the wire can be prevented. Good ultrasonic connection. The gas guide 18 can be modified not only in the structure shown in FIG. 3 but also in the structure shown in FIG. Specifically, a tape having electrical insulation properties such as tetrafluoroethylene, heat resistance, and flexibility, and more specifically, a sealing tape used for sealing the connection portion of the pipe (for example, a VALQUA tape seal under the product name) is wound. It is turned to form a flexible tube 20. In this modification, since the tape is wound while being displaced from the tip end portion of the pipe 17 in the axial direction of the pipe, the tip end portion of the tubular portion 20 is thin and has good flexibility, and thus ultrasonic vibration is applied. Even if the capillary 4 is touched, the energy of ultrasonic vibration is not absorbed so much and the bonding is not affected.
Can be brought close to the position of contacting the capillary 4. In this modification, the tape is wound in multiple layers, but a wide tape may be wound in one layer or may be wound in a gutter-shaped half rotation. 6 shows a modified example of the gas guide 18,
A tubular member 21 formed of a resin having heat resistance, electrical insulation, and flexibility such as silicone resin, one end of which is fitted into the gas supply pipe 17 and the other end of which is formed to have a small diameter and a thin wall. . Since this gas guide 18 is a molded body, it can be easily attached to or replaced with the gas supply pipe 17. Further, in the illustrated example, the gas discharge port 18 of the gas guide 18
The small-diameter portion of the a portion was formed into a simple tubular shape, but a constricted portion or a bellows portion is formed in the axially intermediate portion of the small-diameter portion to improve flexibility of the small-diameter portion, and the flexible resin is tubular. The flexibility reduced by molding can be improved by imparting flexibility, and even if the gas guide 18 comes into contact with the capillary 4, the influence on ultrasonic vibration can be reduced.
Incidentally, the present invention is not limited to the above-mentioned embodiment, for example, this device is not limited to the semiconductor wafer,
The present invention can be applied to a printed wiring board used for a hybrid integrated circuit device or a general electronic circuit device by forming a conductive pattern on an insulating substrate. Further, a notch or a through hole may be provided in the upper and lower portions of the open end of the gas guide 18, and the capillary 4 may be inserted into this notch.

[0007]

As described above, according to the present invention, since the gas discharge port is made as close as possible to the capillary, even if the gas supply amount is reduced and the gas pressure discharged from the gas discharge port is lowered. The discharge region can be sufficiently maintained in a non-oxidizing atmosphere, the utility cost can be reduced, and a forced ventilation device is not required, so that the entire facility can be downsized. Also, after the ball is formed, the capillary can be lowered and immediately connected to the substrate,
The electrode forming work can be speeded up and the processing time can be shortened. Moreover, since the capillary is always cooled by the gas discharged from the gas discharge port during operation, even if the material that is easily softened when the wire that is the electrode material is heated,
Since the temperature rise is suppressed during operation and softening is prevented, the ultrasonic vibration from the capillary can be transmitted to the bonding interface between the ball and the electrode formation planned portion without being attenuated, and good bonding can be performed.

[Brief description of drawings]

FIG. 1 is a cross-sectional perspective view of essential parts of a bump electrode forming apparatus showing an embodiment of the present invention.

FIG. 2 is a front sectional view of the apparatus shown in FIG.

FIG. 3 is an enlarged side sectional view showing an example of a gas discharge port.

FIG. 4 is a diagram showing a relationship between a gas flow rate and a distance between a capillary and a gas guide.

FIG. 5 is an enlarged side sectional view showing another example of the gas discharge port.

FIG. 6 is an enlarged side sectional view showing another example of the gas discharge port.

FIG. 7 is a cross-sectional perspective view of essential parts showing a conventional bump electrode forming apparatus.

FIG. 8 is a front sectional view of the apparatus shown in FIG.

[Explanation of symbols]

 1 Support Table 2 Substrate (Semiconductor Wafer) 3 Horn 4 Capillary 5 Wire 5a Ball 9 Bump Electrode 10 Discharge Electrode 17 Gas Supply Pipe 18 Gas Guide 18a Gas Discharge Port

Claims (5)

[Claims] 1. A substrate supporting an electrode formation planned portion is supported by X.
A support table whose movement is controlled in the Y direction, a capillary through which a wire made of an electrode material is inserted to move vertically and ultrasonic vibration is applied, and a capillary which is arranged so as to be capable of reciprocating in a horizontal plane including a position below the capillary, A discharge electrode set to a relatively high potential relative to the wire protruding from the lower end,
The gas supply pipe to which a non-oxidizing gas is supplied is arranged above the moving plane of the discharge electrode, one end communicates with the gas supply pipe, and the gas discharge part at the other end is arranged as close as possible to the lower end of the capillary. And a gas guide which is formed by a non-oxidizing gas discharged from the gas guide, and discharges between the wire protruding from the lower end of the capillary and the discharge electrode in the atmosphere formed by the non-oxidizing gas to form a molten ball at the lower end of the wire. A bump electrode forming apparatus characterized in that a bump electrode is formed by applying a ultrasonic vibration while pressing a ball to the electrode formation planned portion of the substrate at the lower end of the capillary to connect to the electrode formation planned portion of the substrate. 2. A gas guide is connected to the gas supply pipe, the gas guide being made of a material having electrical insulation and capable of suppressing the influence on the ultrasonic vibration as much as possible even when the capillary comes into contact with the gas supply pipe. The bump electrode forming device according to claim 1. 3. The bump electrode formation according to claim 2, wherein a tape member having electrical insulation and flexibility is wound around the outer periphery of the end portion of the gas supply pipe to form a gas guide. apparatus. 4. The bump electrode according to claim 2, wherein a tubular member having electrical insulation and flexibility is fitted to an end of the gas supply pipe to form a gas guide. Forming equipment. 5. The bump electrode forming apparatus according to claim 2, wherein the distance between the outer periphery of the lower end of the capillary and the gas discharge portion of the gas guide is set within 2.5 mm.