JP3714293B2 - Electronic component bonding tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component bonding tool for bonding an electronic component such as a bumped electronic component such as a flip chip to a surface to be bonded such as an electrode of a substrate.
[0002]
[Prior art]
As a method for bonding an electronic component to a surface to be bonded such as an electrode of a substrate, a method using ultrasonic pressure welding is known. In this method, ultrasonic vibration is applied to the electronic component while pressing the electronic component against the surface to be joined, and the joining surface is brought into close contact by causing the joining surface to vibrate minutely to generate friction. The bonding tool used in this method has a horn that is an elongated rod body that transmits the vibration of an ultrasonic vibrator, which is a vibration generation source, to an electronic component. The electronic component is bonded and bonded to the surface to be bonded while adsorbing the component and applying a load and vibration to the electronic component.
[0003]
Conventionally, a horn similar to a horn used in a wire bonding apparatus has been used as a horn for ultrasonically welding electronic components. This type of horn has a cantilever structure, and a suction portion is held at the free end of the tip, and ultrasonic pressure welding is performed by attracting an electronic component to the suction portion.
[0004]
[Problems to be solved by the invention]
However, since the conventional horn has a cantilever structure, the vibration state is unstable, and stable bonding is difficult. Further, since the suction part is also held at the free end of the horn, the vibration state is unstable. In addition, since a load (load and vibration) at the time of bonding acts on the suction portion, the lower surface (the suction surface of the electronic component) is easily worn. If this wear increases, the suction part must be attached to and detached from the horn and replaced. However, this replacement must be simple and quick, and even if the suction part is replaced, the vibration characteristics of the suction part may not change. It is essential.
[0005]
Accordingly, an object of the present invention is to provide an electronic component bonding tool capable of performing stable bonding while performing stable vibration. It is another object of the present invention to provide a bonding tool for an electronic component that can easily and quickly replace the suction portion and that does not change the vibration characteristics of the suction portion even if the suction portion is replaced.
[0006]
[Means for Solving the Problems]
The present invention is a bonding tool for an electronic component that presses the electronic component against a surface to be bonded while applying a load and vibration to the electronic component, and includes a horizontally long horn, a vibrator that applies vibration to the horn, and an adsorption a suction unit for vacuum suction an electronic component in the hole, said suction pads connected to communicating the suction device to the suction hole and a suction hole abuts, said suction unit is detachably mounted to said horn, said The suction portion is tapered downward, and the tapered shape has a tapered side surface. A contact element is brought into contact with the tapered side surface, and the contact element is detachably fixed to the horn. By doing so, the adsorption part is detachably attached to the horn .
[0007]
In the above configuration, if the lower surface of the suction portion is worn, the suction portion is removed from the horn and replaced. In addition, by making the suction part taper downward, it is possible to perform stable bonding while making the suction part perform stable vibration, and even if the suction part is replaced, the vibration characteristics of the suction part are unlikely to change. It will be a thing.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. 1 is a front view of an electronic component bonding apparatus according to an embodiment of the present invention, FIG. 2 is a vertically inverted perspective view of the bonding tool for the electronic component, and FIG. 3A is a front view of the bonding tool for the electronic component. 3 (b) is a bottom view of the bonding tool for the electronic component, FIG. 3 (c) is a front view of the disassembled state of the bonding tool for the electronic component, and FIG. FIG. 3E is a partial cross-sectional view of the bonding tool for the electronic component.
[0009]
First, the overall structure of an electronic component bonding apparatus will be described with reference to FIG. Reference numeral 1 denotes a support frame, and a first elevating plate 2 and a second elevating plate 3 are provided on the front surface thereof so as to be movable up and down. A cylinder 4 is mounted on the first lifting plate 2, and its rod 5 is coupled to the second lifting plate 3. A bonding head 10 is attached to the second lifting plate 3. A Z-axis motor 6 is provided on the upper surface of the support frame 1. 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. Therefore, when the Z-axis motor 6 is driven and the feed screw 7 rotates, 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.
[0010]
In FIG. 1, a substrate 46 as a bonded surface is placed on a substrate holder 47, and the substrate holder 47 is placed on a table 48. The table 48 is a movable table, and horizontally moves the substrate 46 in the X direction or the Y direction to position the substrate 46 at a predetermined position.
[0011]
Reference numeral 42 denotes a camera, which is mounted on the uniaxial table 43. Reference numeral 44 denotes a lens barrel extending forward from the camera 42. An electronic component with a bump such as a flip chip, for example, as a bonded article that is moved forward along the uniaxial table 43 and the tip of the lens barrel 44 is adsorbed and held on the lower surface of the bonding tool 14 as indicated by a chain line The position of the electronic component 40 and the substrate 46 is observed by the camera 42 in this state. And the relative position shift of the electronic component 40 and the board | substrate 46 is detected by this observation result. The detected positional deviation is corrected by driving the table 48 and horizontally moving the substrate 46 in the X direction or the Y direction, whereby the electronic component 40 and the substrate 46 are aligned.
[0012]
In FIG. 1, reference numeral 50 denotes a main control unit that controls the Z-axis motor 6 through the motor drive unit 51, controls the table 48 through the table control unit 52, and controls the camera 42 through the recognition unit 53. And a suction device 56 is connected. Further, the cylinder 4 as the pressing means is connected to the main control unit 50 via the load control unit 54, and the pressing load that presses the bumped electronic component 40 against the substrate 46 with the bonding output 14 of the rod 5 of the cylinder 4. Is controlled. The vibrator 17 including an ultrasonic vibrator is connected to the main control unit 50 via the ultrasonic vibrator driving unit 55 and performs ultrasonic vibration in accordance with a command from the main control unit 50.
[0013]
A holder 12 is coupled to the lower end of the main body 11 of the bonding head 10. A block 13 is attached to the holder 12, and a bonding tool 14 is fixed to the block 13. The protrusion 13 a on the side of the block 13 is connected to the suction device 56. Hereinafter, the bonding tool 14 will be described with reference to FIGS. 2 and 3.
[0014]
As shown in FIGS. 2 and 3, the bonding tool 14 mainly includes a horizontally long horn 15. The horn 15 is an elongated rod-like body, and has a tapered surface 15a that becomes gradually narrower from both side portions toward the center in a plan view. At the center of the horn 15, a suction part 30 protrudes downward, and ribs 15 b are provided integrally with the horn 15 at four positions that are equidistant from the suction part 30. In order to improve the mounting balance to the block 13, the four ribs 15 b are projected symmetrically in plan view with the suction portion 30 at the center of the horn 15 as the center. The bonding tool 14 is detachably mounted on the lower surface of the block 13 by screwing screws 18 into through holes 20 formed in the ribs 15b. That is, the rib 15 b is a mounting portion for mounting the horn 15 to the block 13.
[0015]
In FIG. 3C, the adsorbing portion 30 has a tapered shape that becomes gradually narrower downward, and both side surfaces thereof are tapered surfaces 31. An adsorption hole 32 is formed at the center. A protrusion 30 a (FIG. 2) that sucks the electronic component 40 is provided on the lower surface of the suction part 30. A protrusion 33 projects from the upper surface of the horn 15 opposite to the suction section 30, and a recess 34 into which the protrusion 33 is fitted is formed on the lower surface of the horn 15. FIG. 3E shows a state in which the protrusion 33 is fitted in the recess 34. In this state, the projection 33 fits closely into the recess 34, but a slight gap C is secured between the upper surface of both sides of the suction portion 30 and the lower surface of the horn 15. Therefore, the contact length between the suction portion 30 and the horn 15 is a length that substantially goes around the protrusion 33 indicated by L in the drawing. Thus, by ensuring the clearance C and shortening the contact length L as much as possible, even if the suction part 30 is replaced, the vibration characteristics of the suction part 30 hardly change, and the reproducibility of the vibration characteristics is extremely good. It becomes.
[0016]
In FIG. 3C, a first hole 35 and a second hole 36 in which threads are formed are formed on the lower surface of the horn 15 on both sides of the recess 34. Reference numeral 37 denotes an abutment element. As shown in FIG. 3D, the inner end surface 37 a is a tapered surface that abuts against the tapered surface 31. Reference numeral 38 denotes a positioning pin for the contact piece 37, which is inserted into and fixed to the second hole 36. By inserting the screw 39 through the through-hole 37c of the abutment 37 and inserting the outer end surface 37b of the abutment 37 into the first hole 35 while abutting against the pin 38, the adsorbing portion 30 is placed on the lower surface of the horn 15. It is attached detachably. In this way, the contact portion 37 is brought into contact with the tapered surface 31 of the suction portion 30, and the lateral displacement of the suction portion 30 is restricted by the pin 38, so that the suction portion 30 can be securely attached to the horn 15.
[0017]
Further, by forming both side surfaces of the horn 15 into tapered surfaces 15a that gradually become narrower toward the suction portion 30, vibration of the vibrator 17 can be efficiently and intensively applied to the suction portion 30. By making the taper 30 taper downward, the vibration of the suction portion 30 can be stabilized, and the vibration can be concentrated and strongly applied to the electronic component 40 sucked on the lower surface thereof. Thus, it is desirable for the adsorption | suction part 30 to taper downward and to provide the vibration to the electronic component 40. As shown in FIG. As a shape which makes the adsorption | suction part 30 into a taper shape, it is good also as a taper shape in step shape other than the taper surface 31, for example.
[0018]
In FIG. 1, a suction pad 19 is attached to a protrusion 13 a provided on the side surface of the block 13. In FIG. 3C, suction holes 16 a and 16 b communicating with the suction hole 32 of the suction portion 30 are formed in the horn 15, and the suction pad 19 is in contact with the suction hole 16 b on the upper surface of the horn 15. Therefore, by sucking air by driving the suction device 56 (FIG. 1) connected to the suction pad 19, vacuum suction is performed from the suction holes 32 (FIGS. 3A and 3B) opened in the suction portion 30. The electronic component 40 with bumps can be vacuum-sucked and held on the lower surface of the suction portion 30.
[0019]
In FIG. 2, a vibrator 17 that is a vibration applying unit is attached to a side end of the horn 15. By driving the vibrator 17, longitudinal vibration (vibration in the longitudinal direction of the horn 15) is applied to the horn 15, and the suction unit 30 vibrates in the horizontal direction a (longitudinal direction of the horn 15). As shown in FIG. 3B, the shape of the horn 15 is such that the width is sequentially reduced in the direction of the center from both ends through the tapered surface 15a. In the transmission path, the amplitude of the ultrasonic vibration is amplified, and vibration larger than the amplitude oscillated by the vibrator 17 is transmitted to the adsorption unit 30.
[0020]
Next, a mode of vibration excited on the horn 15 by the vibrator 17 will be described. As shown in FIG. 3A, the standing wave A of vibration excited by the horn 15 has the position of the attachment portion 30 of the vibrator 17 and the suction portion 30 located at the center of the horn 15 as the antinode of the standing wave. The positions of the ribs 15b and the suction holes 16b as fixing portions for fixing the horn 15 to the block 13 are formed into nodes of standing waves. That is, such a standing wave can be generated in the horn 15 by appropriately setting the shape and mass distribution of each part of the horn 15.
[0021]
Accordingly, the rib 15b as the mounting portion corresponds to a node of the standing wave that is equidistant from the suction portion 30 that is a position corresponding to the antinode of the standing wave of the horn 15 in the direction of both ends of the horn 15. It is provided in the position to do. As a result, the bonding tool 14 is fixed to the block 13, and the displacement due to the longitudinal vibration of the horn 15 is minimized at the position of the rib 15b that transmits the pressing force of the cylinder 4 to the horn 15 through the position corresponding to the node of the standing wave. In addition, a maximum amplitude is obtained at the position of the suction portion 30 that holds the electronic component 40, and ultrasonic vibration can be most effectively used for bonding the electronic component 40.
[0022]
In FIG. 3A, a protrusion 41 protrudes from the center of the upper surface of the horn 15. The protrusion 41 is on the upper surface of the horn 15 on the opposite side of the suction portion 30, and the suction portion 30 with respect to the horizontal neutral axis NA of the horn 15 and its mounting means (abutment 37, pin 38, screw 39, etc.) The mass balance is taken. The operation of the protrusion 41 is as follows. That is, the vibration of the vibrator 17 is transmitted as longitudinal vibration in the longitudinal direction of the horn 15 (arrow a in FIG. 2), and this longitudinal vibration causes the electronic component 40 to vibrate in the horizontal direction with respect to the joint surface. The electronic component 40 is bonded by this friction.
[0023]
Here, assuming that there is no protrusion 41, the horn 15 loses its Z-direction (vertical direction) mass balance with respect to the neutral axis NA due to the suction part 30 protruding from the lower surface in the vicinity of the center. 15 generates vibration in the Z direction. This vibration in the Z direction acts as a force that strikes the electronic component 40 against the upper surface of the substrate 46 that is the surface to be bonded, and thus not only inhibits the bonding but also destroys the electronic component 40 in some cases. Therefore, by forming the protrusion 41, a mass balance with the suction portion 30 with respect to the neutral axis NA is secured, and vibration in the Z direction is prevented. That is, the protrusion 41 is a mass balance means.
[0024]
【The invention's effect】
According to the present invention, if the lower surface of the suction portion is worn, the suction portion can be removed from the horn and replaced easily. In addition, by making the suction part taper downward, it is possible to perform stable bonding while making the suction part perform stable vibration, and even if the suction part is replaced, the vibration characteristics of the suction part are unlikely to change. It will be a thing. Further, by providing the mass balance means, it is possible to prevent the horn from vibrating in the Z direction and to securely bond the electronic component to the surface to be joined.
[Brief description of the drawings]
FIG. 1 is a front view of an electronic component bonding apparatus according to an embodiment of the present invention. FIG. 2 is a vertically inverted perspective view of an electronic component bonding tool according to an embodiment of the present invention. 1B is a front view of an electronic component bonding tool according to an embodiment of the invention; FIG. 2B is a bottom view of an electronic component bonding tool according to an embodiment of the present invention; and FIG. (D) Cross-sectional view of the contact of the bonding tool for electronic components according to the embodiment of the present invention (e) Partial sectional view of the bonding tool for electronic components according to the embodiment of the present invention Explanation of symbols]
14 Bonding tool 15 Horn 15a Tapered surface 17 Vibrator 19 Suction pad 30 Suction part 31 Tapered surface 37 Contact 40 Electronic component 41 Projection (mass balance means)

Claims (1)

A bonding tool that presses the electronic component against the surface to be bonded while applying a load and vibration to the electronic component. The horizontal horn, a vibrator that applies vibration to the horn, and the electronic component are vacuum-adsorbed to the suction holes. And a suction hole with which a suction pad connected to the suction device contacts with the suction hole, the suction part is detachably mounted on the horn, and the suction part is tapered downward. And the tapered portion has a tapered side surface, a contact piece is brought into contact with the tapered side face, and the contact piece is detachably fixed to the horn, thereby bonding tool you wherein electronic components that detachably mounted to said horn.

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