JP2009090296A - Ultrasonic vibration welding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic vibration welding device which attains downsizing of a resonator, while highly retaining stiffness of the resonator. <P>SOLUTION: The resonator 7 is constituted by one wavelength of a resonance frequency so that both ends positions f0 and f4 of the resonator may become maximum amplitude points. A holding means 40 to hold a chip 23 is arranged at the position f4 of the maximum amplitude point which is one end of the resonator 7. A first clamp means 21 and a second clamp means 22 are inserted into and engaged with a position f3 of a first minimum amplitude point, and a position f1 of a second minimum amplitude point, respectively, and the resonator 7 is supported. Moreover, a distance L2 from the position f4 of the maximum amplitude point up to an end face of the holding means 40 is constituted to be shorter than a distance L1 from the position f3 of the first minimum amplitude point up to an end of an opposite side to a base 20 side of the first clamp means 21. With such constitution, ultrasonic vibration welding can be performed with high accuracy, and furthermore downsizing of the equipment can be attained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for joining a plurality of objects to be joined by applying ultrasonic vibrations to a plurality of objects to be joined as objects to be joined.

  Conventionally, as a method of bonding a plurality of objects to be bonded, ultrasonic vibration energy is applied to the objects to be bonded for a predetermined time while pressurizing the plurality of objects to be bonded with a predetermined pressurizing force. There is a joining method called ultrasonic vibration joining that joins joined objects. In this joining method, by joining the objects to be joined together by ultrasonic vibration, a new surface appears between the objects to be joined and the objects to be joined can be joined.

  As an example of a joining apparatus that realizes such an ultrasonic vibration joining method, there is one described in Patent Document 1. This Patent Document 1 describes an ultrasonic vibration bonding apparatus configured to support a resonator with a vibration isolation support member. Specifically, the vibration isolation support member includes a first cylinder to which the first diaphragm is attached and a second cylinder to which the second diaphragm is attached, and stores the booster inside the first cylinder. Subsequently, the booster protruding from the first cylinder is taken into the second cylinder, and the second cylinder is mounted coaxially with the first cylinder, and the front and rear ends of the booster are connected to the first diaphragm and the second diaphragm. The length is adjusted so that it abuts, and the booster is built in the vibration isolation support member. And, at the rear end of the booster, a vibrator is coaxially coupled with a first diaphragm interposed therebetween, and at the front end of the booster, an ultrasonic horn provided with a holding means for holding an object to be joined at one end, The second diaphragm is coupled coaxially.

  Another example of a conventional ultrasonic vibration bonding apparatus is disclosed in Patent Document 2. In the apparatus described in Patent Document 2, a supported portion for supporting the resonator by the support means is formed at the position of the minimum amplitude point (nodal point) sandwiching the maximum amplitude point on the center axis of the resonator. is doing. Here, the minimum amplitude point is a node of a standing wave generated in the resonator, and is a point where expansion and contraction do not occur in the central axis direction of the resonator, which is the vibration transmission direction. That is, a concave portion is formed on the outer peripheral surface of the resonator at the position of the minimum amplitude point to support a position closer to the minimum amplitude point.

In the device of Patent Document 2, the holding means for holding the object to be bonded to the resonator is the outer peripheral surface of the resonator at the position of the maximum amplitude point at which the amplitude in the central axis direction of the resonator is maximum. The resonator is disposed at a portion corresponding to approximately the center of the length in the central axis direction of the resonator. This position is also a position corresponding to the center of pressurization of the resonator, and this configuration enables efficient and stable ultrasonic vibration bonding while maintaining high rigidity.
Japanese Patent No. 3078231 (paragraph 0032, FIG. 9 etc.) Japanese Patent Laying-Open No. 2006-156970 (paragraphs 0019, 0031, 0040, FIG. 8, 10 etc.)

  However, in the apparatus described in Patent Document 1, since the resonator is supported by the diaphragm, there is a problem that when pressurizing, the rigidity is weak and a large pressure cannot be applied. In addition, the length is adjusted so that the front and rear ends of the booster are in contact with the first diaphragm and the second diaphragm, and the booster is built in the vibration isolation support member, which is difficult and inconvenient to adjust manually. is there.

  On the other hand, in the apparatus described in Patent Document 2, the position of the minimum amplitude point that sandwiches the maximum amplitude point on the central axis of the resonator is supported by the support means. The minimum amplitude point is a point where expansion and contraction do not occur in the direction of the center axis of the resonator. No vibration occurs at the minimum amplitude point on the center axis of the resonator, but the minimum amplitude point is perpendicular to the center axis of the resonator. Considering a cross section when cut by a plane, the further the distance from the minimum amplitude point, the more the resonator expands and contracts, causing vibration. In addition, the same vibration is generated at positions other than the minimum amplitude point as the distance from the center axis of the resonator increases. Therefore, in order to stably support the resonator and form a highly rigid resonator, a concave portion is formed on the outer peripheral surface of the resonator at the position of the minimum amplitude point so that a position closer to the minimum amplitude point is formed. This is a configuration that eliminates the problem of Patent Document 1 described above.

  However, in the apparatus described in Patent Document 2, the support means of the resonator is larger than the outer periphery of the resonator and protrudes from the holding means, and the holding means is provided between the support means. Therefore, the size of the stage for holding another object to be joined disposed at a position facing the holding means provided in the resonator is limited by the distance between the support means. Is done. Therefore, when the stage size is large, it is necessary to replace the resonator with a resonator having a large distance between the support means of the resonator, which causes a new problem that miniaturization of the resonator is prevented.

  Therefore, as a method of performing bonding using a stage larger than the distance between the support means of the resonator in the resonator as described in Patent Document 2, the height of the holding means in the stage direction is increased, It can be considered that the end surface of the holding means protrudes in the stage direction from the above-described resonator support means. However, in the case where the end surface of the holding means is protruded in this way, the vibration is transmitted to the outside of the resonator as the distance from the center axis of the resonator is increased as described above. Due to the hardness and elastic properties of the material between the central axis and the end surface of the holding means, the object to be held contains vibrations that are different from the vibration direction of the resonator and are transmitted to the object to be bonded. For example, abnormal vibration including vibration perpendicular to the vibration direction of the resonator is also generated, which may cause destruction or damage of the bonded object.

  In view of the above-described problems, an object of the present invention is to provide an ultrasonic vibration bonding apparatus that realizes downsizing of a resonator while maintaining high rigidity of the resonator.

  In order to achieve the above-described object, an ultrasonic vibration bonding apparatus according to the present invention includes a plurality of objects to be bonded that are provided with a resonator that is elongated in the axial direction and a support unit that supports the resonator, and are polymerized as bonding objects. In an ultrasonic vibration bonding apparatus that applies ultrasonic vibration to a plurality of objects to be bonded, a holding unit that holds the objects to be bonded on one end side of the resonator, and other resonators A resonator provided coaxially with the shaft at the end, and the resonator includes a maximum amplitude point at which the amplitude in the axial direction is maximum at the one end of the shaft, and the end along the axis from the one end. A first minimum amplitude point at which the amplitude is minimum at a position having a length of 1/4 wavelength of the resonance frequency, and a second minimum at which the amplitude is minimum at a position different from the first minimum amplitude point along the axis. An amplitude point and the position of the resonator at the position of the first and second minimum amplitude points. First and second supported portions formed to be recessed in a peripheral surface, the support means is inserted into the first and second supported portions to support the resonator, and the holding means is The object to be joined is held in contact with the outer peripheral surface of the resonator between the first supported portion and one end of the resonator (Claim 1).

  In the ultrasonic vibration bonding apparatus according to the present invention, the support means includes a base, and first and second clamp means provided on the base so that the support means can be fitted into the first and second supported parts. A distance L1 from the first minimum amplitude point to the tip of the first clamping means on the side opposite to the base side is from the maximum amplitude point to the end face of the holding means in a state of holding the workpiece. It is characterized by being formed longer than the distance L2.

  According to the first aspect of the present invention, since the holding means is disposed at one end of the resonator at the position of the maximum amplitude point, the size of the stage is limited by the distance between the support means of the resonator. It can handle any size stage. Thereby, the size of the resonator can be reduced, and the apparatus can also be reduced in size. Further, since the concave portion is formed as the supported portion at the position of the minimum amplitude point of the resonator and is supported by the supporting means, the rigidity of the resonator can be kept high. As a result, even when the holding means is disposed at one end of the resonator that is not the center of pressurization, desired ultrasonic vibration can be efficiently transmitted to the object to be bonded while applying a large pressing force.

  According to the second aspect of the present invention, since the resonator expands and contracts as the distance from the center axis of the resonator increases, the vibration is transmitted to the outside of the resonator. By holding the distance L2 from the maximum amplitude point to the end face of the holding means in a state where the workpiece is held shorter than L1, and by reducing the distance from the center axis of the resonator to the end face of the holding means, the holding means Then, abnormal vibration including vibration in a direction different from the vibration direction of the resonator can be suppressed. Therefore, it is possible to efficiently transmit the vibration in the vibration direction of the resonator to the holding means, and it is possible to suppress the destruction and damage of the object to be joined caused by abnormal vibration or the like.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of an embodiment of an ultrasonic vibration bonding apparatus according to the present invention. 2 is a configuration diagram of a resonator included in the ultrasonic vibration bonding apparatus shown in FIG. 1. (a) is a left side view when viewed from one end where the holding means is disposed, and (b) is a left side view. A front view and (c) are bottom views. FIG. 3 is a configuration diagram of the resonator supported by the support means. FIG. 4 is a right side view of FIG. 3 and is a cross-sectional view of the resonator taken along line AA.

(Device configuration)
In the ultrasonic vibration bonding apparatus shown in FIG. 1, a chip 23 having a metal melt bump 23 a made of lead-tin solder on a bonding surface of a semiconductor, which is an object to be bonded that is held by the resonator 7, The substrate 24 having the metal melt bumps 24a, which are the objects to be joined, held by the stage 10 disposed facing the resonator 7 is melted by a vertical drive mechanism 25 capable of controlling the pressure. The chip 23 and the substrate 24 are bonded together by applying ultrasonic vibration by the vibrator 8 and the resonator 7 while applying pressure so that the bump 23a and the metal melt bump 24a are in contact with each other. As described above, the ultrasonic vibration bonding apparatus according to the present invention is configured such that various devices such as various semiconductor devices or MEMS devices can be formed by bonding the chip 23 and the substrate 24.

  As shown in FIG. 1, the ultrasonic vibration bonding apparatus according to the present invention includes a bonding mechanism 27, a mounting mechanism 28 having a stage 10 and a stage table 12, a position recognition unit 29, a transport unit 30, and a control device 31. And. The joining mechanism 27 includes a vertical drive mechanism 25 and a head portion 26. The vertical drive mechanism 25 guides the resonator holding portion 6 with the vertical guide 3 by the vertical drive motor 1 and the bolt / nut mechanism 2. It is configured to move up and down. The joining mechanism 27 is coupled to the frame 34, and the frame 34 is connected to the gantry 35 by the four support columns 13 disposed so as to surround the periphery of the pressure center of the head portion 26. A part of the support column 13 and the frame 34 is not shown.

  The resonator holding unit 6 is guided in the vertical direction by the head escape guide 5 and is connected to the bolt / nut mechanism 2 while being pulled by the own weight counter 4 for canceling the own weight. A head unit 26 having a resonator 7 is coupled to the resonator holding unit 6.

  The resonator holding unit 6 is provided with a pressure sensor 32, which can detect a pressure applied to an object (chip 23, substrate 24, etc.) sandwiched between the resonator 7 and the stage 10. It is configured as follows. Therefore, by feeding back the pressure applied to the workpiece detected by the pressure sensor 32 to the control device 31, the vertical drive mechanism 25 is controlled based on the feedback value to control the pressure applied to the workpiece. be able to.

  The head unit 26 includes a support unit including the resonator 7, a holding unit 40 that holds the chip 23 by suction, the vibrator 8, the base unit 20, the first clamping unit 21, and the second clamping unit 22. . The holding means 40 is disposed by adhering to a position f4 (see FIG. 2) which is one end of the resonator 7 and the maximum amplitude point of the resonator 7 with a thermosetting adhesive or the like. The other end of the resonator 7 is disposed so as to be coaxial with the center axis of the resonator 7. Further, the height of the head portion 26 can be detected by the resonator height detecting means 36 provided in the resonator holding portion 6. The configuration and operation of the head unit 26 will be described in detail later.

  The mounting mechanism 28 includes a stage 10 that holds the substrate 24 by suction, and has a stage 10 and a stage table 12 having a movable axis that can be moved in parallel and rotationally to adjust the position of the substrate 24 with respect to the chip 23. The stage 10 includes a holding mechanism (not shown) for holding the substrate 24. Here, as a holding mechanism of the stage 10, a mechanism using a holding mechanism by vacuum suction is used. Note that the holding means 40 may be one that utilizes electrostatic attraction, or the holding means 40 may be simply placed on another holding mechanism or the stage 10.

  The position recognizing unit 29 is inserted between the chip 23 and the substrate 24 arranged to face each other, and the upper and lower mark recognizing means 14 for recognizing the alignment marks for position recognition of the upper and lower chips 23 and the substrate 24 respectively. 23, an amplitude detector 33 for detecting the amplitudes of the substrate 24 and the resonator 7, and a recognition means moving table 15 for moving these recognition means 14 and the amplitude detector 33 horizontally and / or vertically.

  Further, the transport unit 30 includes a chip supply device 16 and a chip tray 17 that transport the chips 23, and a substrate transport device 18 and a substrate transport conveyor 19 that transport the substrate 24. Further, the control device 31 controls ultrasonic vibration energy and the like obtained from the pressure applied to the head unit 26 and the voltage value and / or current value applied to the vibrator 8. Further, the control device 31 includes an operation panel (not shown) for controlling the entire ultrasonic vibration bonding apparatus, and is based on a detection signal of the height position of the head portion 26 by the resonator height detection means 36. The vertical drive mechanism 25 can be controlled to adjust the height of the head portion 26 in the direction of arrow Z in FIG. The configuration and operation of the control device 31 will be described later in detail.

(Resonator)
Next, the head unit 26 will be described in detail with reference to FIGS. The resonator 7 is made of, for example, a titanium alloy (6Al-4V), and a vibrator 8 is disposed at a position f0 that is one end of the resonator 7, and the vibrator 8 is controlled by the control device 31. Due to the generated ultrasonic vibration, the resonator 7 vibrates in the central axis direction. Further, as shown in FIG. 2, the resonator 7 is configured with a length of one wavelength of the resonance frequency so that the substantially center position f2 of the resonator 7 and both end positions f0 and f4 are the maximum amplitude points. Has been. In this case, the positions f3 and f1 that are a quarter wavelength away from the maximum amplitude point correspond to the first and second minimum amplitude points, respectively.

  2A and 2B are schematic configuration diagrams of the resonator 7. FIG. 2A is a left side view as viewed from the position f4, FIG. 2B is a front view, and FIG. 2C is a bottom view. As shown in FIG. 5A, the resonator 7 has a cylindrical shape with a circular cross section viewed from the position f4. Then, as shown in FIG. 4C, in the vicinity of f4, the side surface of the cylinder is tapered as it approaches the position f4 to form a taper shape, and the cross-sectional shape viewed from the position f4 is a substantially rectangular plate shape. It is formed as follows. Then, as shown in FIG. 5A, the resonator 7 is installed so that the rectangular short side of the left side surface is vertically arranged when the plate-shaped rectangle is viewed from the position f4 side. On the upper and lower surfaces, holding means 40 for holding the chip 23 which is an object to be bonded is disposed.

  Further, as shown in FIGS. 2B and 2C, the outer periphery of the resonator 7 is formed in a concave shape at the position f3 which is the first minimum amplitude point and the position f1 which is the second minimum amplitude point of the resonator 7. Thus, a first supported portion 41 and a second supported portion 42 for supporting the resonator 7 are configured. The first supported portion 41 and the second supported portion 42 have an octagonal cross-sectional shape when cut in a cross section perpendicular to the central axis of the resonator 7. The cross-sectional shapes of the first supported portion 41 and the second supported portion 42 are not limited to octagons, and may be circular or other polygonal shapes.

  FIG. 3 is a configuration diagram of the resonator 7 supported by the support means. As shown in FIG. 3, the resonator 7 is supported in the first supported portion 41 and the second supported portion 42 by the supporting means including the base 20 and the first clamping means 21 and the second clamping means 22. Yes. FIG. 4 is a cross-sectional view of the resonator 7 shown in FIG. As shown in the figure, the upper member 22a and the lower member 22b of the second clamping means 22 supported by the base portion 20 are fitted into the second supported portion 42, and the upper member 22a and the lower member 22b are fixed by the bolt 43. Thus, the resonator 7 is sandwiched. Similarly, the upper member 21a and the lower member 21b of the first clamping means 21 supported by the base portion 20 are fitted into the first supported portion 41, and the upper member 21a and the lower member 21b are fixed by the bolt 43, The resonator 7 is sandwiched. The base 20 is fixed to the resonator holding unit 6, and is configured to apply the pressure applied by the vertical drive mechanism 25 to the chip 23 and the substrate 24.

  The resonator 7 is configured to be rotatable about the center axis of the resonator 7 by loosening the bolt 43, and is rotated 180 degrees about the center axis of the resonator 7 by loosening the bolt. Thus, the bonded portion 40 can be exchanged. The method for fixing the resonator 7 to the first clamp means 21 and the second clamp means 22 is not limited to the bolt 43, and any method may be used. A clamp mechanism may be used.

  Further, as shown in FIG. 3, the resonator 7 has a distance L2 from the position f4 which is the maximum amplitude point of the resonator 7 to the end face of the holding means 40 in a state where the chip 23 which is the object to be bonded is held. It is configured to be shorter than the distance L1 from the position f3 which is one minimum amplitude point to the tip of the first clamping means 21 on the side opposite to the base 20 side.

  The holding means 40 is made of, for example, a material such as Ni, Cu, or Ag, and is bonded to the resonator 7 with a thermosetting resin or the like. Further, it may be formed by cutting directly from the resonator 7. Furthermore, the holding means may be made of a material other than metal, such as cemented carbide tungsten carbide, ceramics, diamond, or may be bonded to the resonator 7 with a metal brazing material such as Ni, Cu, or Ag. In addition, the holding means 40 is provided with a holding mechanism (not shown) by vacuum suction as an example in order to hold the chip 23 as an object to be bonded. The holding mechanism may be configured to maintain the object to be bonded by electrostatic adsorption, a mechanical chuck, or the like, and is not limited thereto, and is configured to directly bond the object to be bonded to the holding means 40. Also good.

  By adopting such a configuration for the head portion 26, a stage of any size can be disposed on the stage 10 without being limited by the distance between the first clamp means 21 and the second clamp means 22. . In addition, the first clamp means 21 and the second clamp means are connected to the first held means 41 and the second held means 42 formed at the position f3 that is the first minimum amplitude point and the position f1 that is the second minimum amplitude point, respectively. Since the resonator 7 is supported by the means 22 being inserted and inserted, the rigidity of the resonator 7 can be kept high. Therefore, even if the holding means 40 is disposed at one end of the resonator 7, a large pressure can be applied to the chip 23 and the substrate 24 while maintaining high rigidity.

  Further, the distance L2 from the position f4 which is the maximum amplitude point of the resonator 7 to the end face in the state where the chip 23 of the holding means 40 is held is the base 20 of the first clamping means 21 from the position f3 which is the first minimum amplitude point. Since the configuration is shorter than the distance L1 to the tip opposite to the side, the holding means 40 can suppress abnormal vibration including vibration in a direction different from the vibration direction of the resonator 7, and the like. The vibration in the vibration direction can be efficiently transmitted to the chip 23 and the substrate 24 for bonding. An example of the joining operation is shown below.

(Joining operation)
Next, a series of operations for joining the metal melt bumps 23a of the chip 23 and the metal melt bumps 24a of the substrate 24 by ultrasonic vibration to mount the chip 23 on the substrate 24 will be described.

  First, the chip 23 and the substrate 24 that are the objects to be bonded are installed. The chip 23 is supplied from the chip tray 17 to the resonator 7 by the chip supply device 16 and is sucked and held. Further, the substrate 24 is supplied from the substrate transfer conveyor 19 to the stage 10 by the substrate transfer device 18 and held by suction. The upper / lower mark recognition means 14 is inserted by the recognition means moving table 15 between the chip 23 and the substrate 24, the bonding surfaces of which are held opposite to each other, and the alignment marks for alignment between the chips 23 and the substrate 24 held opposite to each other are inserted. The position is detected by the upper and lower mark recognition means 14. Thereafter, the position of the chip 23 and the substrate 24 is adjusted by moving the stage table 12 in parallel and rotating with the position of the chip 23 as a reference, thereby moving the position of the substrate 24.

  Next, the upper and lower mark recognizing means 14 is retracted by the recognizing means moving table 15 in a state where the joining positions of the chip 23 and the substrate 24 are aligned (the positions of the metal fusion bumps 23a and 24a are aligned). Subsequently, the head unit 26 starts to descend by the vertical drive mechanism 25, and the chip 23 and the substrate 24 are brought close to each other. When the metal melt bumps 23 a of the chip 23 and the metal melt bumps 24 a of the substrate 24 come into contact, the chip 23 and the substrate 24 are sandwiched between the resonator 7 and the stage 10 based on a detection signal from the pressure sensor 32. Is detected.

  Then, the vertical drive motor 1 installed in the vertical drive mechanism 25 is controlled by the control device 31, a predetermined pressure is applied to the chip 23 and the substrate 24, and ultrasonic vibration bonding is started. During the bonding, for example, the control device 31 monitors and controls the ultrasonic vibration energy obtained from the current value and the voltage value applied to the vibrator 8, the resonance amplitude of the resonator 7, and the applied pressure.

  Since the bonding surfaces of the chip 23 and the substrate 24 have small unevenness and a difference in height at a plurality of bonding portions, the bonding area gradually increases in the process of bonding. Then, since the bonding force between the chip 23 and the substrate 24 gradually increases, the magnitude of “slip” between the chip 23 and the substrate 24 gradually decreases. The bonding force between the chip 23 and the substrate 24 becomes larger than the frictional force between the holding means 40 holding the chip 23 and the chip 23 or between the substrate 24 and the stage 10, and the holding means 40 and the chip 24. When a force greater than the maximum static frictional force between the holding means 40 and the chip 23 or between the substrate 24 and the stage 10 is applied between the holding means 40 and the stage 10, the holding means 40 and the chip 23. The friction coefficient between the substrate 24 and the stage 10 shifts from the static friction coefficient to the dynamic friction coefficient, and “slip” occurs between the holding means 40 and the chip 23 or between the substrate 24 and the stage 10. Therefore, the ultrasonic vibration transmitted from the vibrator 8 is not sufficiently transmitted to the chip 23 and the substrate 24, and the joining does not proceed.

  Therefore, when the pressing force is increased to increase the frictional force between the holding means 40 and the chip 23 or between the substrate 24 and the stage 10 with time from the start of the joining, between the holding means 40 and the chip 23 or between the substrate 24 and the stage. 10 "slip" is suppressed, ultrasonic vibration is transmitted to the chip 23, and "slip" between the chip 23 and the substrate 24 increases, so that a new surface appears on the joint surface between the chip 23 and the substrate 24, The bonding area becomes larger.

  However, as described above, as the bonding area increases, the “slip” between the chip 23 and the substrate 24 decreases. Therefore, control is performed so that the applied pressure is increased, the ultrasonic vibration energy is increased, and the “slip” between the chip 23 and the substrate 24 is maintained at a predetermined value.

  Specifically, the controller 31 applies a predetermined pressure p and ultrasonic vibration energy e to advance the bonding operation, and the amplitude detector 33 detects “slip” between the chip 23 and the substrate 24. In some cases, when the “slip” becomes equal to or less than a predetermined value, the control device 31 performs control to increase the applied pressure and the ultrasonic vibration energy by Δp and Δe, respectively. For the values of Δp and Δe, optimum values depending on the types of the chip 23 and the substrate 24 may be obtained in advance. The ultrasonic vibration energy is controlled by, for example, the phase of the voltage and current applied to the vibrator 8 being matched, the vibration amplitude of the resonator 7 and the magnitude of “slip” between the chip 23 and the substrate 24. May be performed by adjusting the current while maintaining the voltage of the vibrator 8 at a predetermined value so that is maintained at a predetermined value.

  As an example, the oscillation frequency of the vibrator 8 is set to 50 kHz, and the voltage applied to the vibrator 8 is set within a range of 0V to 10V. Further, although there is a difference depending on the member, area, etc., as an example, the magnitude of “slip” between the chip 23 and the substrate 24 has an amplitude of about 0.1 μm to 0.5 μm.

  And joining is complete | finished when a joining area reaches the target value. At the end of joining, the pressure, ultrasonic vibration energy and joining time necessary for joining the intended joining area are obtained in advance, and the time when the target value is reached is regarded as the end of joining.

  When the bonding of the chip 23 and the substrate 24 is completed, the adsorption of the chip 23 by the resonator 7 is released, and the return movement of the head unit 26 is performed. Thereafter, in a state where the chip 23 is mounted, the substrate 24 held on the stage 10 is discharged to the substrate transport conveyor 19 by the substrate transport device 18, and a series of joining operations is completed.

  Thus, by transmitting ultrasonic vibration while applying pressure to the chip 23 and the substrate 24, it is possible to cause a certain “slip” on the bonded surface between the metal melt bumps 23a and 24b. It is possible to remove an adhering layer such as an organic substance or an oxide film adhering to the surfaces of the metal melt bumps 23a and 24b. Therefore, these metal melt bumps 23a and 24b can be joined without using a flux (flux) conventionally required for joining these metal melt bumps 23a and 24b.

  According to the embodiment described above, since the holding means 40 is disposed at one end of the resonator 7 at the position of the maximum amplitude point f4, the size of the stage 10 is the first clamping means of the resonator 7. Regardless of the distance between 21 and the second clamping means 22, the stage 10 can be arranged in any size. Thereby, the size of the resonator 7 can be reduced, and the apparatus can also be reduced in size.

  In addition, a concave portion is formed on the outer peripheral surface of the resonator 7 at the position f3 which is the first minimum amplitude point and the position f1 which is the second minimum amplitude point of the resonator 7 to form the first supported portion 41 and the second supported portion 41. Since the supported portion 42 is formed, and the first clamp means 21 and the second clamp means 22 are respectively inserted into the first supported portion 41 and the second supported portion 42 to support the resonator 7, The rigidity of the resonator 7 can be kept high. As a result, even if the holding means 40 is disposed at one end of the resonator 7 that is not the center of pressurization, it is possible to efficiently transmit desired ultrasonic vibrations to the chip 23 and the substrate 24 while applying a large pressure. It is.

  Furthermore, according to the above-described embodiment, since the resonator 7 is expanded and contracted as the distance from the central axis of the resonator 7 is increased, the ultrasonic vibration is transmitted to the outside of the resonator 7. 7, the distance L2 from the position f4 which is the maximum amplitude point at one end to the end surface of the holding means 40 in the state where the chip 23 is held is set to the base 20 side of the first clamping means 21 from the position f1 which is the first minimum amplitude point. By forming the distance L1 shorter than the distance L1 to the tip on the opposite side and reducing the distance L2 from the center axis of the resonator 7 to the end face of the holding means 40, the holding means 40 has a direction different from the vibration direction of the resonator 7. Abnormal vibrations including the vibrations can be suppressed. Therefore, it is possible to efficiently transmit the vibration in the vibration direction of the resonator 7 to the holding means 40, and it is possible to suppress the destruction and damage of the chip 23 and the substrate 24 caused by abnormal vibration or the like.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

  For example, as shown in FIG. 2, the resonator 7 has a shape near the position f <b> 4 where the holding means 40 is disposed, and the side surface of the cylinder is cut away toward the position f <b> 4 to form a tapered shape. Although it has been described that the cross-sectional shape viewed from f4 is a substantially rectangular plate, it is not limited to such a shape.

  As an example, as the position f4 is approached, the entire outer periphery of the cylinder is tapered so that the cross-sectional shape viewed from the position f4 is an octagon and is held on each surface orthogonal to each side of the octagon. The means 40 may be joined. By making such a shape and reducing the distance from the central axis of the resonator 7 to the end face of the holding means 40, the occurrence of abnormal vibration or the like can be further suppressed. Further, the smaller the cross-sectional area at the position f4, the more the vibration is amplified, and a large vibration amplitude can be efficiently transmitted to the chip 23 and the substrate 24. Further, the holding means 40 can be more frequently and simply replaced by joining the holding means 40 to each surface orthogonal to each side of the octagonal cross-sectional shape. The cross-sectional shape of the position f4 is not limited to a rectangle or an octagon, but may be another polygon or a circle.

  Further, although the resonator 7 is made of a titanium alloy (6Al-4V) in the present embodiment, other materials such as iron, titanium, and stainless steel may be used.

  Further, the size of the resonator 7 in the central axis direction is not limited to the length of one wavelength of the resonance frequency of the resonator 7. Such a length may be used.

  In the present embodiment, the holding means 40 is directly bonded and fixed to the resonator 7 with a thermosetting adhesive. However, the bonding method is not limited to the thermosetting adhesive. After applying Ni plating or the like to the metal, a metal braze such as Ag, Cu, or Ni may be brazed as an adhesive. The fixing method is not limited to adhesion, and the holding means 40 may be directly attached to the resonator 7 with a bolt or the like. Further, it may be formed by cutting out from the resonator 7 and integrated with the resonator 7.

  In the control method of the present embodiment, the voltage value, current value, applied pressure, time, and the like necessary for achieving the target bonding area are obtained and set in advance at the end of bonding. The ultrasonic vibration energy may be monitored, and the time point when the ultrasonic vibration energy decreases may be set as the end of bonding.

  In this case, the end of bonding for each object to be bonded can be determined regardless of the type of the object to be bonded, the surface condition, and the like, so that the pressure and ultrasonic vibration energy are applied to the chip 23 and the substrate 24 even after the bonding is completed. It is possible to prevent the chip 23 and the substrate 24 from being broken.

  Further, regarding the device configuration, in order to obtain “slip” between the chip 23 and the substrate 24, a plurality of amplitude detectors 33 may be provided, and the amplitude of the chip 23 and the substrate 24 may be measured simultaneously. After measuring the amplitude of the chip 23 and the substrate 24 in order with one amplitude detector 33, the amplitude difference is calculated in a state where the time axis is shifted and the time axis is overlapped, thereby the “slip between the chip 23 and the substrate 24. Can also be measured. If the chip 23 and the substrate 24 are securely held by the resonator 7 and the stage 10, it is only necessary to detect the amplitude of either the chip 10 or the substrate 24.

  As the amplitude detector 33, any known detector such as an eddy current type, a capacitance type, a light irradiation type, or a sound wave detection type may be used. By using these means, for example, cost reduction can be achieved as compared with the case of using a laser Doppler measuring device.

  In addition to the upper and lower mark recognizing means 14 and the amplitude detector 33, the position recognizing unit 29 is configured to emit light by causing the light emitting element to function electrically when the light emitting element is bonded as an object to be bonded. It is good also as providing the luminescent point recognition means utilized when adjusting the position of joining objects.

  Furthermore, ultrasonic vibration bonding may be performed while heating the chip 23 and the substrate 24 by the heaters 9 and 11 disposed on the base 20 of the support means and the stage 10. The heaters 9 and 11 may be of any system such as a constant heat system or a pulse heat system. Further, the heater 9 for heating the chip 23 may be disposed in the first and second clamping means 21 and 22, the holding means 40, or the resonator 7 instead of the base 20.

  In this case, since the energy of ultrasonic vibration and the energy of heating are used in combination, the chip 23 and the substrate 24 can be bonded by the bonding energy generated efficiently. Further, the control device 31 controls the heating temperature and timing as well as the pressing force and the ultrasonic vibration energy, so that the chip 23 and the substrate 24 can be moved in a short time with less pressing force and ultrasonic vibration energy. The devices can be formed by bonding. Therefore, it is possible to prevent the chip 23 and the substrate 24 from being damaged by applying excessive pressure or ultrasonic vibration energy to the chip 23 and the substrate 24 at the time of device creation, and to provide a highly accurate device. .

  Further, the holding mechanism installed in the holding means 40 and the stage 10 for holding the chip 23 and the substrate 24 is not limited to the holding mechanism based on vacuum suction, but is also based on a holding mechanism using an electrostatic chuck, a mechanical chuck mechanism, or a magnetic suction mechanism. For example, a well-known holding mechanism may be employed.

  For example, if the holding means 40 and the stage 10 are provided with an electrostatic chuck means to adsorb the chip 23 and the substrate 24, the chip 23 can be held in a vacuum, so the chip 23 and the substrate 24 in a vacuum. And impurities such as organic substances and oxide films are prevented from adhering to the chip 23 and the substrate 24, so that the chip 23 and the substrate 24 can be bonded satisfactorily.

  In the present embodiment, the stage 10 side has a horizontal position adjustment function and the head portion 26 side has a vertical drive function. However, the horizontal position adjustment function and the vertical drive function have the stage 10 side and the head portion 26. You may combine in any way and you may comprise so that it may overlap.

  Further, in the present embodiment, the head unit 26 and the stage 10 are arranged in the vertical direction (the direction of the arrow Z shown in FIG. 1), and the chip 23 and the substrate 24 that are objects to be joined are overlapped and joined in the vertical direction. However, the arrangement direction is not limited to this, and a configuration may be employed in which the layers are joined in the left-right direction substantially orthogonal to the up-down direction. Further, three or more objects to be joined may be polymerized and joined.

  Further, in the present embodiment, the method based on the torque control of the vertical drive motor 1 is shown as the pressurizing unit, but the pressurizing unit using the fluid pressure by the air cylinder may be used.

Further, the object to be joined may be a material other than a semiconductor (such as a resin substrate, a film substrate, or a chip obtained by dicing these substrates). Further, the object to be bonded may be any object as long as it can be bonded by transmitting ultrasonic vibration. For example, a metal melt bump or wiring pattern is formed on a wafer or chip formed of a metal such as Si, SiO ₂ , glass, lithium ionic acid, oxide single crystal (LT), or an oxide containing a ceramic system. Can be joined together.

  The material for forming the metal melt bumps 23a and 24a is not limited to lead-tin solder, but may be other metals or other metals as long as they can be joined by applying ultrasonic vibration.

  The form of the object to be joined may be any substrate, wafer, chip obtained by dicing the substrate and the wafer, or the like. The metal melt bumps 23a and 24a may have a plurality of individual bump shapes, or a certain region between the objects to be joined is connected to the contour so that the objects to be joined can be sealed. The shape may be different. Further, instead of joining the metal melt bumps 23a and 24a, the entire one surface of the objects to be joined may be joined.

1 is a schematic configuration diagram of an embodiment of an ultrasonic vibration bonding apparatus according to the present invention. It is a figure of the resonator with which the ultrasonic vibration joining apparatus shown in FIG. 1 is equipped, Comprising: (a) is the side view seen from the one end side in which the holding means was arrange | positioned, (b) is a bottom view, (c) is a front view FIG. It is a front view of the state which supported the resonator shown in FIG. 2 by the support means. FIG. 4 is a cross-sectional view taken along line AA of the resonator shown in FIG. 3.

Explanation of symbols

7 …… Resonator 8 …… Oscillator 10 …… Stage 20 …… Base (supporting means)
21 …… First clamping means (supporting means)
22 …… Second clamping means (supporting means)
23 …… Chip (bonded object)
24 …… Substrate (Substrate)
31 …… Control device 40 …… Holding means 41 …… First supported portion 42 …… Second supported portion f0, f2, f4 …… Maximum amplitude point f1 …… First minimum amplitude point f3 …… Second minimum Amplitude point

Claims (2)

An ultrasonic transducer that includes an axially long resonator and a support means for supporting the resonator, and applies ultrasonic vibrations to a plurality of objects to be bonded as objects to be bonded to bond the plurality of objects to be bonded together. In the ultrasonic vibration bonding apparatus,
Holding means for holding the object to be bonded at one end of the resonator;
A vibrator provided coaxially with the shaft at the other end of the resonator;
The resonator has a maximum amplitude point at which the amplitude in the axial direction is maximum at the one end of the shaft, and a minimum amplitude at a position of a quarter wavelength of the resonance frequency from the one end along the axis. The first minimum amplitude point, the second minimum amplitude point at which the amplitude is minimum at a position different from the first minimum amplitude point along the axis, and the positions of the first and second minimum amplitude points. First and second supported portions formed to be recessed in the outer peripheral surface of the resonator,
The support means is inserted into the first and second supported parts to support the resonator, and the holding means is provided between the first supported part and one end of the resonator. An ultrasonic vibration bonding apparatus characterized in that the object to be bonded is held in contact with an outer peripheral surface. The support means includes a base, and first and second clamp means provided on the base so as to be fitted into the first and second supported parts.
A distance L1 from the first minimum amplitude point to the tip of the first clamping means opposite to the base side is:
2. The ultrasonic vibration bonding apparatus according to claim 1, wherein the ultrasonic vibration bonding apparatus is formed longer than a distance L <b> 2 from the maximum amplitude point to an end surface of the holding unit in a state where the workpiece is held.

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