JP2004031994A - Electronic component bonding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component bonding device that does not damage the quality of an electronic component by suppressing the occurrence of vertical flexural vibrations. <P>SOLUTION: In this electronic component bonding device which press-fixes the electronic component to a substrate by imparting vibrations to the component while pressing the component against the substrate by means of a bonding tool 14, a fixing seat 15a which fixes the tool 14 to a block 13 which moves upward and downward with respect to the substrate is provided at the position corresponding to the antinode of the standing wave of the vibration of a horn 15, and the seat 15a and the main body section of the horn 15 are connected to each other through a connecting section A having a thin cross section and vertically symmetrical notched sections B. Consequently, the flexural rigidity of the cross section of the connecting section A can be reduced, and the occurrence of the vertical displacement of the horn 15 caused by flexural vibrations excited in a fixing section can be suppressed by suppressing the transmission of the flexural vibrations to the main body of the horn 15. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an electronic component bonding apparatus for bonding an electronic component to a surface to be compressed such as a substrate.

A method using ultrasonic pressure welding is known as a method for mounting an electronic component such as a bumped electronic component on a work such as a substrate. In this method, ultrasonic vibration is applied while pressing the bumps of the electronic component against the substrate, and the bonding surfaces are rubbed against each other for bonding. The bonding tool used in this method has a horn, which is an elongated rod that transmits the vibration of the ultrasonic vibrator, which is the vibration source, to the joint, and a node of the standing wave of the vibration generated in the horn. Is fixed, and the portion corresponding to the antinode having the largest amplitude is pressed against the joint to effectively use the vibration.

However, the position of the node of the standing wave of the vibration is not always in a fixed position in every state, and a slight shift occurs depending on the temperature state of the bonding tool and the state of the load applied to the bonding tool. For this reason, at the time of actual bonding, vibration also exists at the position set at the design stage as the position of the node where vibration is originally minimal, and this vibration is transmitted to the fixed portion projecting from both sides of the horn. Then, a new vibration is excited in the fixed portion by this vibration. At this time, since the fixed portion has a mechanically asymmetric structure in which the upper portion is fixed to the bonding apparatus and the lower portion is the free end, the vibration excited by the fixed portion has the amplitude of the lower free end portion. Is larger than the upper part, that is, bending vibration that generates bending stress in the fixed part.

曲 げ And the bending vibration excited by this fixed part is transmitted to the horn on the contrary, and acts on the horn body as a vibrating force to induce the bending vibration. When bending vibration occurs in the horn, a displacement occurs in the horn in the vertical direction, that is, a direction in which the electronic component is pressed against the surface to be pressed. Since this vertical displacement does not contribute to the thermocompression bonding of electronic components at all, it also causes damage to the electronic components and causes poor quality, so bending vibration of the horn must be eliminated as much as possible. . However, in the conventional bonding tool, no consideration is given to the bending vibration generated in the horn, and a bonding tool that takes this surface into consideration has been desired.

Therefore, an object of the present invention is to provide an electronic component bonding apparatus that suppresses the occurrence of bending vibration in the vertical direction and does not impair the quality of the electronic component.

An electronic component bonding apparatus according to the present invention includes an electronic component bonding tool including an electronic component bonding tool for applying vibration while pressing an electronic component against a surface to be pressed while being in contact with the electronic component and pressing the electronic component against the surface to be compressed. Wherein the bonding tool has a horn vibrated by a vibrator, a crimping surface formed on the horn and pressing an electronic component against a surface to be crimped, and a position corresponding to a node of a standing wave of vibration of the horn. A connecting portion protruding from the horn, and a fixing portion formed at a tip portion of the connecting portion and fixing the horn to an elevating member of a bonding apparatus, and fixing an upper portion of the fixing portion to the elevating member, The lower part of the fixed part was a free end.

An electronic component bonding apparatus according to the present invention includes a connecting portion protruding from a horn at a position corresponding to a node of a standing wave of vibration of a horn, and a horn formed at a distal end portion of the connecting portion fixed to a lifting member of the bonding device. A fixing portion for fixing the upper portion of the fixing portion to the elevating member and a lower end of the fixing portion as a free end, thereby suppressing transmission of bending vibration excited by the fixing portion to the horn body. However, the occurrence of vertical displacement due to the bending vibration of the horn can be suppressed.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of an electronic component bonding apparatus according to one embodiment of the present invention, FIG. 2 is a perspective view of an electronic component bonding tool according to one embodiment of the present invention, and FIG. FIG. 3B is a front view of an electronic component bonding tool according to an embodiment, FIG. 3B is a plan view of an electronic component bonding tool according to an embodiment of the present invention, and FIGS. FIG. 2 is a partial perspective view of the electronic component bonding tool according to the embodiment.

First, the overall structure of the electronic component 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. Therefore, 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, the substrate 32, which is a surface to be pressed, is placed on a substrate holder 34, and the substrate holder 34 is placed on a table 35. The table 35 is a movable table that horizontally moves the substrate 32 in the X and Y directions to position the substrate 32 at a predetermined position.

# 42 denotes a camera, which is mounted on the uniaxial table 43. A lens barrel 44 extends forward from the camera 42. The camera 42 is advanced along the uniaxial table 43, and the tip of the lens barrel 44 is positioned between the electronic component 30 with bumps and the substrate 32 held by being sucked and held on the lower surface of the bonding tool 14 as shown by a chain line, In this state, the positions of the electronic component 30 with bumps and the substrate 32 are observed with the camera 42. Then, the relative displacement between the electronic component 30 and the substrate 32 is detected based on the observation result. The detected positional deviation is corrected by driving the table 35 to move the substrate 32 horizontally in the X direction or the Y direction, whereby the electronic components 30 with bumps and the substrate 32 are aligned.

In FIG. 1, reference numeral 50 denotes a main control unit which controls the Z-axis motor 6 via a motor drive unit 51, controls the table 35 via a table control unit 52, and controls the camera 42 via a recognition unit 53. It is connected to the. The cylinder 4 is connected to the main control unit 50 via a load control unit 54, and the protrusion output of the rod 5 of the cylinder 4, that is, the pressing load for pressing the electronic component 30 against the substrate 32 by the bonding tool 14 is controlled.

ホ ル ダ A holder 12 is coupled to the lower end of the main body 11 of the bonding head 10. A block 13 (elevating member) is mounted on the holder 12, and a bonding tool 14 is fixed to the block 13. Hereinafter, the block 13 and the bonding tool 14 will be described with reference to FIGS.

As shown in FIG. 2, the horn 15 of the bonding tool 14 is an elongated rod-like body, and mounting seats 15 a as fixing portions are provided on four sides of the horn 15 at equal distances from the center of the horn 15. ) Is provided integrally with the horn 15. The bonding tool 14 is fixed to the lower surface of the block 13 by a mounting seat 15a. That is, the mounting seat 15a is a fixing portion for fixing the horn 15 to the elevating member of the bonding apparatus.

(4) A holding portion 15e, which projects downward and holds the electronic component 30 by vacuum suction, is provided on a lower surface of a central portion of the bonding tool 14, and a lower surface of the holding portion 15e is a pressing surface 15f of the electronic component 30. One end of an inner hole 16 for vacuum suction provided in the horn 15 is opened in the crimping surface 15f to form a suction hole 16a. The other end of the inner hole 16 opens at the position of the mounting seat 15a on the upper surface of the horn 15 to form a suction hole 16b.

A tube portion 18 is provided to protrude downward from the protrusion 13 a provided on the side surface of the block 13, and the suction pad 19 attached to the lower end of the tube portion 18 as shown in FIG. It is in contact with the position of the suction hole 16b on the upper surface. Therefore, the suction device 21 is driven to suck air from the tube 20 connected to the protrusion 13a and communicating with the tube 18 through the inner hole 13b of the protrusion 13a, so that the tube 20 is opened to the crimping surface 15e through the inner hole 16. Vacuum suction is performed through the suction holes 16a (FIGS. 3A and 3B), and the electronic component 30 with bumps can be held by vacuum suction on the crimping surface 15f.

A vibrator 17 is mounted on the side end surface of the horn 15. By driving the vibrator 17, longitudinal vibration is applied to the horn 15, and the holding portion 15e vibrates in the horizontal direction. As shown in FIG. 3B, the horn 15 has a shape in which the width is gradually reduced in the direction of the center portion 15d from the both end portions 15b through the tapered portion 15c. The amplitude of the ultrasonic vibration is amplified in the path transmitted to the portion 15e, and a vibration having an amplitude equal to or greater than the amplitude oscillated by the vibrator 17 is transmitted to the holding portion 15e.

Next, the mode of vibration excited by the horn 15 by the vibrator 17 will be described. As shown in FIG. 3A, the standing wave of the vibration excited by the horn 15 changes the position of the mounting surface of the vibrator 17 and the position of the crimping surface 15 f of the holding portion 15 e located at the center of the horn 15. The position of the connecting portion of the mounting seat 15a for fixing the horn 15 to the block 13 and the position of the suction hole 16b form a node of the standing wave. That is, such a standing wave can be generated in the horn 15 by appropriately setting the shape and size and the mass distribution of each part of the horn 15.

Therefore, the mounting seat 15a, which is a connecting portion, is connected to a node of the standing wave that is equidistantly spaced from the crimping surface 15f, which is a position corresponding to the antinode of the standing wave of the vibration of the horn 15, toward both ends of the horn 15. It is provided integrally at a corresponding position. Accordingly, the displacement of the horn 15 due to the longitudinal vibration is minimized at the position of the mounting seat 15a to which the bonding tool 14 is fixed, and the maximum amplitude is obtained at the position of the crimping surface 15f for crimping the electronic component 30 with bumps. The vibration can be used most effectively for bonding the electronic component 30 with bumps. Furthermore, by integrating the mounting seat 15a with the horn 15, the mounting of the bonding tool 14 to the block 13 (elevating member) can be performed with good workability.

Here, the shape of the mounting seat 15a will be described with reference to FIG. As shown in FIG. 4A, the mounting seat 15a is connected to the horn 15 by thin connecting portions A that protrude horizontally from both side surfaces of the main body of the horn 15. In addition, a notch B having a vertically symmetric shape is provided at an upper portion and a lower portion of the connecting portion A. The cross-sectional shape of the connecting portion A (see the hatched portion in the drawing) is set to a size and shape that minimizes the bending rigidity of the cross-section as much as possible within a sufficient range for the bonding load of the target electronic component 30. . That is, the thickness t of the connecting portion A is made as small as possible and the cutout portion B is made as large as possible within a range having sufficient strength against the pressing load at the time of bonding. As described below, reducing the bending stiffness of the cross section of the connecting portion A is of great significance in improving the utilization efficiency of ultrasonic vibration during bonding and preventing damage to the electronic component 30 during bonding, as described below. Having.

That is, as described above, the connecting portion A is set at a position corresponding to a node of the standing wave generated in the horn at the design stage, but generally, during actual bonding, the position of the connecting portion A is determined by various uncertain factors. Does not exactly match the standing wave node. Therefore, vibration also exists at the position of the connecting portion A, and this vibration is transmitted to the mounting seat 15a. Here, since the mounting seat 15a has an upper part fixed to the block 13 and a lower part as a free end, bending vibration is excited in the mounting seat 15a as shown in FIG. 4B. When this bending vibration is transmitted to the main body of the horn 15 via the connecting portion A, the horn 15 is displaced in the vertical direction due to the bending vibration shown by the broken line. This vertical displacement does not contribute to the bonding of the electronic component at all, but acts as a force for pressing the electronic component against the substrate unnecessarily, which is a factor of poor quality.

Here, by minimizing the bending rigidity of the cross section of the connecting portion A as much as possible, the degree of transmission of the bending vibration excited by the mounting seat 15a to the main body of the horn 15 can be minimized. Therefore, the vertical displacement due to the bending vibration induced by the horn 15 can be reduced, and the ratio of the energy of the ultrasonic vibration consumed as the vertical vibration displacement that does not contribute to the bonding can be reduced, and the utilization efficiency of the vibration can be reduced. And the occurrence of damage to the electronic component can be reduced.

電子 The electronic component bonding apparatus is configured as described above, and the operation will be described next. In FIG. 1, the electronic component 30 with bumps is held on the suction surface 15 e of the bonding tool 14 by vacuum suction and positioned above the substrate 32. Then, the lens barrel 44 is advanced, the camera 42 obtains the images of the electronic component 30 with bumps and the substrate 32, and the image data is sent to the recognition unit 53. The main control unit 50 detects a relative displacement between the electronic component 30 with bumps and the substrate 32 from the image data, drives the table 35 according to the detection result, and performs the position correction by moving the substrate 32 horizontally.

Next, the Z-axis motor 6 is driven to lower the bonding head 10 and press the bumps of the electronic component 30 with bumps against the substrate 32. At this time, the substrate 32 is heated by a heating unit (not shown). Then, the vibrator 17 is driven in a pressed state to apply vibration to the bumped electronic component 30. Thereby, the pressing surface between the bump 31 and the electrode of the substrate 32 is rubbed by the vibration, and the bump 31 is bonded to the electrode of the substrate 32. At this time, the mounting seat 15a for fixing the horn 15 to the block 13 is provided with a thin connecting portion A, and the cross-sectional shape of the connecting portion A is set so as to reduce bending rigidity. As described above, the use efficiency of the ultrasonic vibration can be improved, and damage to the electronic component can be prevented.

ADVANTAGE OF THE INVENTION The bonding apparatus of the electronic component of this invention can suppress the transmission of the bending vibration excited by the fixed part to the horn, therefore, the vertical displacement of the horn caused by the bending vibration of the horn is suppressed, and the thermocompression bonding is performed. This is useful as a bonding device for electronic components, because it is possible to suppress the vertical displacement that does not contribute to the vibration and improve the utilization efficiency of the ultrasonic vibration and prevent damage to the electronic components.

Front view of an electronic component bonding apparatus according to an embodiment of the present invention. 1 is a perspective view of a bonding tool for an electronic component according to an embodiment of the present invention. (A) Front view of electronic component bonding tool according to one embodiment of the present invention (b) Plan view of electronic component bonding tool according to one embodiment of the present invention (A) Partial perspective view of a bonding tool for electronic components according to one embodiment of the present invention (b) Partial perspective view of a bonding tool for electronic components according to one embodiment of the present invention

Explanation of reference numerals

REFERENCE SIGNS LIST 10 bonding head 13 block 14 bonding tool 15 horn 15 a mounting seat 15 e holding portion 15 f crimping surface 16 inner hole 16 a suction hole 16 b suction hole 17 vibrator 19 suction pad 21 suction device 30 electronic component 32 substrate 50 main control portion A connection portion B Notch

Claims (1)

What is claimed is: 1. An electronic component bonding apparatus comprising: a bonding tool for an electronic component that applies vibration while pressing the electronic component against a surface to be compressed while being in contact with the electronic component and presses the electronic component against the surface to be compressed. A horn vibrated by the horn, a crimping surface formed on the horn to press the electronic component against the surface to be crimped, a connecting portion projecting from the horn at a position corresponding to a node of a standing wave of vibration of the horn, A fixing portion formed at the distal end of the connecting portion to fix the horn to the elevating member of the bonding apparatus, wherein an upper portion of the fixing portion is fixed to the elevating member, and a lower portion of the fixing portion is a free end. An electronic component bonding apparatus characterized in that:

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