JPH11345819A - Bonding tool and bonding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact bonding tool and bonding apparatus with improved reliability for vibration propagation. SOLUTION: In a bonding apparatus in which an objet to be bonded is applied with vibration, while it is being pressed to a press-bonded surface by a bonding tool to press-bond it, a pair of piezoelectric elements 23 as vibration generating sources for the bonding tool are disposed on both surfaces of the plate-like part of a fixing member 22, and these vibration generating sources are fastened directly to both end surfaces of a horn 21 for transmitting the vibration to the object to be bonded, with a bolt 24 as a fastening member. Thus, vibration can be transmitted surely without loss, and a compact bonding tool and a bonding apparatus can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding tool and a bonding apparatus for bonding a bonding object such as an electronic component to a surface to be compressed such as a substrate by ultrasonic vibration.

[0002]

2. Description of the Related Art A method using ultrasonic pressure welding is known as a method for joining a bonding object such as an electronic component to a surface to be compressed such as a substrate. In this method, bonding is performed by applying ultrasonic vibration while pressing a bonding object against a surface to be bonded, and causing the bonding surfaces to rub against each other.
In this method, a tool having an ultrasonic vibration source attached to an end of a horn provided with a pressure-bonding surface for pressing against an object to be bonded is used as a bonding tool. The vibration generated by the ultrasonic vibration is amplified by the horn and transmitted to the bonding object via the crimp surface. As a source of the ultrasonic vibration, a commercially available ultrasonic vibrator is generally used as a single vibrator by combining piezoelectric elements.

[0003]

However, when a commercially available ultrasonic vibrator is used for a bonding tool, there are the following problems. First, the reliability of vibration transmission from the ultrasonic transducer is impaired. Ultrasonic vibration is generated by applying an AC voltage to the piezoelectric element, but commercially available ultrasonic transducers do not have a form in which the piezoelectric element directly contacts the horn, and constitute a single ultrasonic transducer. Ultrasonic vibrations are transmitted to the horn via components inevitably added to the horn. Therefore, when a commercially available ultrasonic transducer is used, the vibration is transmitted through many discontinuous surfaces, that is, the boundary surfaces where the parts are in contact with each other, before the vibration is transmitted to the horn. Vibration transmission became unstable depending on the state, and the reliability of vibration transmission was not ensured.

Also, commercially available ultrasonic vibrators cannot be made smaller than the minimum size determined by the wavelength corresponding to the generated frequency, and when mounted on a bonding tool, the overall dimension in the horizontal direction becomes longer. Was a bottleneck in achieving As described above, the reliability of vibration transmission is impaired due to the use of a commercially available ultrasonic transducer in the conventional bonding tool. There is a problem that it is difficult to make the bonding tool compact.

Accordingly, an object of the present invention is to provide a compact bonding tool and a compact bonding apparatus which are excellent in the reliability of vibration transmission.

[0006]

According to a first aspect of the present invention, there is provided a bonding tool which abuts against an object to be bonded and presses the object against the surface to be crimped while applying vibration to press the surface against the surface to be crimped. A fixing member having a plate-shaped portion, a pair of vibrators disposed on both sides of the plate-shaped portion, and a vibrator disposed on a vibrator side of one surface of the plate-shaped portion. And a vibration transmitting member that transmits the vibration transmitting member and the vibrator to the object to be bonded through the joining action portion, the vibration transmitting member being disposed on the vibrator side of the other surface of the plate-shaped portion, and being connected to the vibration transmitting member. A fastening member for fastening to the plate-shaped portion.

According to a second aspect of the present invention, there is provided a bonding apparatus for an electronic component, wherein the bonding tool presses the object to be bonded to the surface to be bonded by applying vibration while pressing the object to be bonded to the surface to be bonded. A fixing member having a plate-like portion, a pair of vibrators arranged on both sides of the plate-like portion, and a vibrator arranged on one side of the vibrator on one surface of the plate-like portion. A vibration transmitting member that transmits the vibration transmitting member to the object to be bonded through the portion, and a vibration transmitting member that is disposed on the vibrator side of the other surface of the plate-shaped portion and that is connected to the vibration transmitting member. And a holder for holding the fixing member, and a driving means for driving the holder to press the bonding action portion against the object to be bonded.

According to the invention described in each of the claims, the vibration, which is a vibration source, is directly connected to the vibration transmitting member for transmitting the vibration to the object to be bonded, whereby the vibration can be transmitted without loss. And a compact bonding tool can be realized.

[0009]

(Embodiment 1) FIG. 1 is a front view of a bonding apparatus according to Embodiment 1 of the present invention, FIG. 2 is a perspective view of the bonding tool, and FIG. 3B is a front view, FIG. 3B is a plan view of the bonding tool, FIG. 3C is a graph showing standing wave vibration of the bonding tool, and FIG. 4 is a graph showing standing wave vibration of the conventional bonding tool. is there.

First, the overall structure of the bonding apparatus will be described with reference to FIG. Reference numeral 1 denotes a support frame, on the front surface of which a first lifting plate 2 and a second lifting plate 3 are provided so as to be able to move up and down. A cylinder 4 is mounted on the first lifting plate 2, and its rod 5 is connected to the second lifting plate 3.
The bonding head 10 is mounted on the second lifting plate 3. On the upper surface of the support frame 1, a Z-axis motor 6 is provided. The Z-axis motor 6 rotates a vertical feed screw 7. The feed screw 7 is screwed into a nut 8 provided on the back surface of the first lifting plate 2. Accordingly, when the Z-axis motor 6 is driven to rotate the feed screw 7, the nut 8 moves up and down along the feed screw 7, and the first lifting plate 2 and the second lifting plate 3 also move up and down.

In FIG. 1, a substrate 32 to be pressed is placed on a substrate holder 33, and the substrate holder 33 is placed on a table 35. The table 34 is a movable table, and horizontally moves the substrate 32 in the X direction and the Y direction to position the substrate 32 at a predetermined position. The main control unit 35 controls the Z-axis motor 6 via the motor drive unit 36 and controls the table 34 via the table control unit 37. The cylinder 4 is connected to the main control unit 35 via a load control unit 38, and the pressing force for pressing the electronic component 30 as a bonding object against the substrate 32 by the bonding tool 20, that is, the projecting output of the rod 5 of the cylinder 4. Controlled.

A holder 12 is connected to the lower end of the main body 11 of the bonding head 10. A bonding tool 20 is fixed to the holder 12. The bonding tool 20 is provided with a vibration source that generates ultrasonic vibration, and the vibration source is driven by an ultrasonic vibration drive unit 39. Hereinafter, the bonding tool 20 will be described with reference to FIGS. As shown in FIG. 2, the bonding tool 2 is attached to the holder 12 via an insulating member 13.
0 is attached. The bonding tool 20 includes a horn 21 as a vibration transmitting member, a fixing member 22, a piezoelectric element 23 as a vibrator, and a bolt 24 as a fastening member for fastening these components.

As shown in FIG. 3B, horns 21 are provided with projections 21a and 21b at the center thereof, which project upward and downward, and the lower projection 21a holds the electronic component 30 by vacuum suction. At the same time, it serves as a bonding action portion 21a that presses the electronic component 30 and bonds it to the substrate. One end of an inner hole 26 for vacuum suction provided in the horn 21 is opened in the joining action portion 21a to form an absorption hole 26a.
The other end of the inner hole 26 is opened on the upper surface of the horn 21 to open the suction hole 2.
6b. A suction pad 27 is provided in the suction hole 26b.
Abuts on a suction device (not shown) through a suction pad 27 to suck air, thereby sucking vacuum from a suction hole 26a through a suction hole 26, and holding the electronic component 30 by vacuum suction on a pressure-bonded surface. can do.

As shown in FIGS. 2 and 3, the horn 2
Vibration sources are mounted on both left and right end surfaces of 1.
The vibration source includes a pair of piezoelectric elements
Are arranged opposite to both surfaces of the plate-shaped portion 22a. As shown in FIG. 2, the piezoelectric element 23 and the horn 2
1 is a plate-like portion 22a of the fixing member 22
Has been concluded. The piezoelectric element 23 is connected to an AC power supply 25 via the fixing member 22, and the bolt 24 is electrically grounded. Accordingly, the horn 21 connected to the bolt 24 is also electrically grounded. By driving the AC power supply 25, an AC voltage is applied to the piezoelectric element 23.

Here, the arrangement of the piezoelectric elements 23 will be described. As shown in FIG. 3A, the piezoelectric element 23 at the left end of the horn 21 has back-to-back polar arrows,
Arrows face each other at the right end. That is, the piezoelectric elements 23 form a pair with opposite polarities, and the polarities of the piezoelectric elements 23 that come into contact with the plate portion 22a are opposite at the right end and the left end of the horn 21. I have to. In other words, the two plate-like portions 22
a, the two inner piezoelectric elements 23 sandwiched between
The two piezoelectric elements 23 outside the two have opposite polarities.

When an AC voltage is applied to the piezoelectric elements 23 arranged in this manner by driving an AC power supply 25, the piezoelectric elements 23 are mechanically vibrated in accordance with the AC frequency, ie, displaced in the longitudinal direction of the horn 21. Generates longitudinal vibrations. As described above, since the polarity of the piezoelectric element 23 is opposite between the inside and the outside of the plate portion 22a, the displacement of the longitudinal vibration is also opposite at the plate portion 22a. As shown in FIG. 3 (c), a standing wave vibration is generated in which the position of the plate-like portion 22a is a node of the vibration and the portion of the joint action portion 21a is the antinode of the vibration.

As shown in FIG. 3A, the horn 21 has a shape in which the width is gradually reduced from both ends in the direction of the central portion 21c. The amplitude of the ultrasonic vibration is amplified in the path transmitted to the piezoelectric element 23, and the vibration having the amplitude equal to or greater than the amplitude oscillated by the piezoelectric element 23 is transmitted to the joint action portion 21a.

Here, as shown in FIG. 3 (c), the distance between the two plate-like portions 22a is equivalent to a half wavelength L / 2 of the longitudinal vibration, and bolts projecting from both sides from the plate-like portion 22a. 24
The entire length of the bonding tool 20 including the above is one wavelength L. This is compared with a conventional bonding tool using a commercially available ultrasonic transducer. As shown in FIG. 4, in the conventional bonding tool 20 ′, since the commercially available ultrasonic vibrator 23 ′, which is the vibration source, is located outside the fixing member 22 ′, the bonding tool 2 ′
The total length of 0 'required a minimum length of 1.5 wavelengths even when the vibration source was arranged on only one side and the length was minimized. If the vibration sources are arranged on both sides of the horn to obtain the symmetry of the vibration, the length of the half wavelength L / 2 is further required.

Therefore, by adopting the configuration in which the piezoelectric element 23 is directly incorporated as described above, vibration sources can be arranged on both sides of the horn 21 to ensure the symmetry of vibration, and at the same time, the bonding tool can be used. , And a compact bonding tool can be realized. In addition, since the piezoelectric element 23 directly contacts the horn 21 to transmit the vibration, there is no loss due to the transmission of the vibration through the discontinuous boundary surface, and the vibration is reliably transmitted.

This bonding apparatus is configured as described above, and the operation will be described below. In FIG. 1, the electronic component 30 is vacuum-adsorbed and held on the bonding action portion 21 a of the bonding tool 20, and is positioned above the substrate 32.
Next, the Z-axis motor 6 is driven to lower the bonding head 10 and press the bumps of the electronic component 30 against the substrate 32.
At this time, the substrate 32 is heated by a heating means (not shown). Then, the ultrasonic vibrator driving unit 39
To apply an AC voltage to the piezoelectric element 23 to transmit vibration to the electronic component 30 with bumps. Thereby, the electronic component 30
The pressing surface between the bump and the electrode of the substrate 32 is rubbed by vibration, and the bump is bonded to the electrode of the substrate 32.
At this time, since the vibration sources are arranged on both sides of the horn 21 of the bonding tool 20, the electronic components 3
A symmetrical vibration without bias is transmitted to 0, so that good bonding quality can be obtained.

(Embodiment 2) FIG. 5 is a side view of a bonding apparatus according to Embodiment 2 of the present invention. In FIG. 5, reference numeral 40 denotes a wire bonding apparatus used for wire bonding for electrically connecting an electronic component to a substrate, and is configured as follows. An L-shaped base 42 is mounted on the XY table 41, and an L-shaped holder 44 is also supported on the base 42. Also,
A voice coil motor 4 as driving means is provided on the base 42.
3 are provided. The voice coil motor 43 has a movable coil disposed in a magnetic field of a magnet. When an AC drive current is supplied to the coil, a movable portion coupled to the coil reciprocates.

The movable part of the voice coil motor 43 is connected to a holder 44. A fixing member 45 having a plate-like portion is provided upright on the holder 44. A bonding tool 46 is connected to the fixing member 45. The bonding tool 46 is composed of a piezoelectric element 47, a horn 48 as a vibration transmitting member, a capillary tool 49 as a bonding action portion attached to the tip of the horn, and a counter member 50 as a fastening member. As in the first embodiment, the piezoelectric elements 47 are arranged on opposite surfaces of the fixing member 45 in pairs having opposite polarities. The vibration of the piezoelectric element 47 is transmitted by the horn 48 via the capillary tool 49 to the wire 51 as the bonding object.

A counter member 50 is connected to the horn 48 by a screw, similarly to the bolt 24 in the first embodiment. By tightening the screw of the counter member 50, the piezoelectric element 47 and the horn 48 are fastened to the fixing member 45. Also, by appropriately setting the shape and dimensions of the counter member 50, the mass distribution of the entire bonding tool 46 is adjusted so that the vibration induced by the piezoelectric element 47 on the bonding tool 46 is symmetrical with respect to the plate member 45. Can be set.

At the tip of the horn 48, a capillary tool 49 is mounted. A wire 51 to be bonded is vertically inserted into the inside of the capillary tool 49. A ball is formed by electric spark at the tip of the wire 51 projecting downward from the lower end of the capillary tool 49, and the ball is pressed against the electrode of the electronic component 52 by the capillary tool 49, thereby forming a wire 5.
1 is joined to the electrode of the electronic component 52 which is the surface to be pressed, and the wire 51 is joined to the electrode of the substrate 53 in the same manner.
2 is electrically connected to the substrate 53.

An AC power supply 54 is connected to the plate-like member 45. When the AC power supply 54 is driven, the piezoelectric element 47 vibrates mechanically similarly to the first embodiment. Transmitted by the capillary tool 49
Vibrates. By driving the voice coil motor 43 to press the wire 51 against the surface to be crimped via the capillary tool 49 and simultaneously vibrate the piezoelectric element 47,
The wire 51 is bonded to the surface to be pressed by the pressing force and the vibration.

At this time, since the piezoelectric element 47 is in direct contact with the horn 48, vibration is reliably transmitted without loss. Further, a counter member 50 is provided to
By arranging the entire bonding tool 49 so as to maintain the symmetry on the mass distribution with respect to the horn 48, the symmetry of the vibration generated in the horn 48 can be secured.

[0027]

According to the present invention, the vibration, which is the vibration source, is directly connected to the vibration transmitting member for transmitting the vibration to the bonding object, whereby the vibration can be transmitted without loss. A compact bonding tool and bonding apparatus are realized. Further, due to the symmetry of the arrangement of the vibration generating sources, the generated vibration has excellent symmetry, and a good bonding result without bias can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a bonding apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the bonding tool according to the first embodiment of the present invention.

FIG. 3A is a front view of the bonding tool according to the first embodiment of the present invention. FIG. 3B is a plan view of the bonding tool according to the first embodiment of the present invention. Graph showing standing wave oscillation

FIG. 4 is a graph showing a standing wave vibration of a conventional bonding tool.

FIG. 5 is a side view of the bonding apparatus according to the second embodiment of the present invention.

[Explanation of symbols]

 12, 44 Holder 20, 49 Bonding tool 21, 48 Horn 22, 45 Fixing member 23, 47 Piezoelectric element 24 Bolt 39 Ultrasonic vibrator drive unit 43 Voice coil motor

Claims (2)

[Claims] 1. A bonding tool that abuts on a bonding object and presses the bonding object against a surface to be compressed by applying vibration while pressing the object against the surface to be bonded. A pair of vibrators arranged on both sides of the plate-shaped portion and a pair of vibrators arranged on one side of the plate-shaped portion on the vibrator side, and transmit the vibration of the vibrator to the object to be bonded through the bonding portion. A vibration transmitting member, and a fastening member arranged on the vibrator side of the other surface of the plate-shaped portion, connected to the vibration transmitting member, and fastening the vibration transmitting member and the vibrator to the plate-shaped portion. A bonding tool, characterized in that: 2. A bonding apparatus for applying a vibration while pressing an object to be bonded to a surface to be bonded by a bonding tool and pressing the object to be bonded to the surface to be bonded, the bonding tool comprising: a fixing member having a plate-shaped portion; A pair of vibrators arranged on both sides of the plate-shaped portion and a pair of vibrators arranged on one side of the plate-shaped portion on the vibrator side, and transmit the vibration of the vibrator to the object to be bonded through the bonding portion. A vibration transmitting member, and a fastening member arranged on the vibrator side of the other surface of the plate-shaped portion, connected to the vibration transmitting member, and fastening the vibration transmitting member and the vibrator to the plate-shaped portion, A bonding apparatus, comprising: a holder for holding the fixing member; and driving means for driving the holder to press the bonding action portion against an object to be bonded.