Ultrasonic bonding tip, ultrasonic bonding apparatus using the same, and ultrasonic bonding method

Abstract

To provide a chip for ultrasonic joining which may achieve improvement of the quality of joint between workpieces, and to provide an ultrasonic joining device and an ultrasonic joining method which use the chip.SOLUTION: In a chip for ultrasonic joining, in a direction perpendicular to an axial direction of a rod part 44 having a substantially cylindrical shape, a ratio (D1 / d1) of a length D1 in an axial direction of the rod part 44 to a maximum distance d1 (a radius of a cross section of a substantially cylindrical shape) from a center of a cross section having a maximum cross-sectional area to a peripheral edge part of the cross section is 30 or larger. Meanwhile, in the direction perpendicular to the axial direction of the rod part 44 having the substantially cylindrical shape, the ratio (D1 / d1) of the length D1 in the axial direction of the rod part 44 to the maximum distance d1 from the center of the cross section having the maximum cross-sectional area to the peripheral edge part of the cross section is 120 or smaller.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic bonding tip that contacts one of the workpieces, such as metals, semiconductors, and / or plastics, in order to bond them using ultrasonic vibrations, as well as an ultrasonic bonding apparatus and an ultrasonic bonding method using the ultrasonic bonding tip. [Background technology]

[0002] Traditionally, ultrasonic bonding has been used to join plastics used in food packaging, or metals such as battery components. Typical ultrasonic bonding devices work by vibrating the tip of a bonding tip (tool) with ultrasonic waves and repeatedly applying pressure to the objects to be bonded (workpieces).

[0003] In ultrasonic bonding, there is an appropriate duration for applying ultrasonic vibrations to the workpiece. As described in Non-Patent Literature 1 below, if the application time is too long, the bonding strength of the joint will decrease, and damage such as cracks may occur in the workpiece.

[0004] Conventionally, bonding methods have been implemented that perform bonding according to a predetermined ultrasonic vibration application time. For example, in Patent Document 1 below, the amplitude of the ultrasonic vibration is increased at the start of bonding, and when a predetermined decay start time is reached, the amplitude of the ultrasonic vibration horn is reduced. Furthermore, after a certain period of time has elapsed, the application of ultrasonic vibration is stopped, and the bonding process is completed. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Hideo Sakuyama, Takehiko Watanabe, Atsushi Yanagisawa, and Shizuyo Onuma, "Ultrasonic Bonding of Aluminum Alloys and Steel," "Abstracts of Presentations at the Japan Welding Society National Convention," 2005, Vol. 2005f, Autumn National Convention, Session ID 416, p. 167. [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2006-263816 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the above method has the following problems.

[0008] The application time of ultrasonic vibration to a workpiece varies depending on the material, shape, method of holding, and / or variations in the workpiece shape. Therefore, it is difficult to individually or precisely pre-determine the appropriate application time. Furthermore, simply setting the application time in advance to account for variations in workpiece shape may not be sufficient to stabilize the bonding strength between workpieces. Moreover, simply pre-setting the decay time of the chip may result in applying more ultrasound than necessary, potentially degrading the quality of the workpiece bonding.

[0009] This invention has been made in view of these circumstances, and aims to provide an ultrasonic bonding tip that can improve the quality of bonding between workpieces, an ultrasonic bonding apparatus using the same, and an ultrasonic bonding method. [Means for solving the problem]

[0010] An ultrasonic bonding tip according to a first aspect of the present invention is An ultrasonic bonding tip for coupling with an ultrasonic vibration device equipped with a vibration element that induces composite vibration by combining longitudinal and torsional vibrations, It has a base portion that is detachably attached to the vibrating element, and a rod portion that extends continuously in the axial direction from the base portion, The rod portion is formed such that, in the direction perpendicular to the axial direction, the ratio of the axial length D1 of the rod portion (D1 / d1) to the maximum distance d1 from the center of the cross-section having the largest cross-sectional area to the peripheral edge of said cross-section falls within the range of 30 to 120, and In a state where the ultrasonic bonding chip is not in contact with the one workpiece, the ultrasonic bonding chip The entire vibration system including is formed such that the ratio f2 / f1 of the resonance frequency f2 of the ultrasonic bonding chip alone to the resonance frequency f1 of the ultrasonic bonding chip is included in the range of 1.005 to 1.07.

[0011] According to the ultrasonic bonding chip having such a configuration, (D1 / d1) is 30 or more. For this reason, before and after the completion of ultrasonic bonding of the one workpiece and the other workpiece with which the ultrasonic bonding chip is in contact, in accordance with the change in the force acting on the ultrasonic bonding chip from the one workpiece, the sensitivity of the change in the amplitude of the ultrasonic vibration of the ultrasonic bonding chip is improved. On the other hand, (D1 / d1) is 120 or less. For this reason, the ultrasonic vibration of the ultrasonic bonding chip is efficiently transmitted to the one workpiece, and thus the bonding efficiency between the one workpiece and the other workpiece is improved.

[0012] Therefore, whether or not the bonding is completed can be accurately determined according to the change mode of the value of the specified parameter that changes according to the progress of the bonding between the one workpiece and the other workpiece, such as the amplitude of the ultrasonic vibration of the ultrasonic bonding chip. When the determination result indicates that the bonding between the one workpiece and the other workpiece is completed, the ultrasonic vibration of the ultrasonic bonding chip is stopped. As a result, the period during which the ultrasonic bonding chip is ultrasonically vibrated can be appropriately controlled from the viewpoint of improving the quality of the bonding between the one workpiece and the other workpiece.

[0013] In the ultrasonic bonding chip having the above configuration, the ratio (S1 / s1) of the maximum cross-sectional area S1 of the base portion in the direction perpendicular to the axial direction of the rod portion to the maximum cross-sectional area s1 of the rod portion in the direction perpendicular to the axial direction is formed to be included in the range of 6.2 to 52.9. This is preferable.

[0014] With the ultrasonic bonding tip of the said configuration, (S1 / s1) is 6.2 or higher. Therefore, the ultrasonic vibrations of the ultrasonic bonding tip are efficiently transmitted to one workpiece, thereby improving the bonding efficiency between that workpiece and the other workpiece. On the other hand, (S1 / s1) is 52.9 or lower. Therefore, before and after the completion of ultrasonic bonding of the workpieces in contact with the ultrasonic bonding tip, the sensitivity of the change in the amplitude of the ultrasonic vibrations of the ultrasonic bonding tip in response to the change in force acting on the ultrasonic bonding tip from one workpiece is improved.

[0017] In the ultrasonic bonding tip having the above configuration, The base is formed such that the cross-sectional area or the maximum distance to the peripheral edge of the cross-section in the direction perpendicular to the axial direction decreases as it approaches the rod portion. It is preferable.

[0018] With this ultrasonic bonding tip configuration, the shape of the tip base has a cross-sectional area perpendicular to the axial direction that decreases as it approaches the rod direction, allowing for the uniform transmission of ultrasonic energy to one of the workpieces. This improves the quality of bonding between the two workpieces.

[0019] In the ultrasonic bonding tip having the above configuration, Due to the difference in materials constituting the base and the rod, the speed of sound in the rod is greater than the speed of sound in the base. It is preferable.

[0020] With the ultrasonic bonding tip of this configuration, the rate of increase in the displacement of the rod portion perpendicular to the axial direction at the point of continuity with the base is suppressed. This stabilizes the ultrasonic composite vibration in the rod portion, and consequently improves the quality of bonding between one workpiece and the other workpiece.

[0021] A second aspect of the present invention is an ultrasonic bonding tip, An ultrasonic bonding tip, which is coupled to an ultrasonic vibration device equipped with a vibration element that induces composite vibration by combining longitudinal and torsional vibrations, and is formed to extend in the axial direction, Regarding the cross-section of the ultrasonic bonding tip perpendicular to the axial direction, the ultrasonic bonding tip has a single designated portion that is locally tapered in the middle portion with respect to the axial direction. The ratio (D2 / d2) of the axial length D2 of the ultrasonic bonding tip to the axial length d2 of the single designated portion is within the range of 1.5 to 3.5. The ratio (S2 / s2) of the maximum cross-sectional area S2 of the ultrasonic bonding tip to the minimum cross-sectional area s2 of the single designated portion in a cross section perpendicular to the axial direction is within the range of 2 to 7, and When the ultrasonic bonding tip is not in contact with the one workpiece, the ultrasonic bonding tip The entire vibration system including The ratio f2 / f1 of the resonant frequency of the ultrasonic bonding tip alone to the resonant frequency f1 of the other device is formed to fall within the range of 1.005 to 1.07.

[0022] With the ultrasonic bonding tip of the said configuration, (D2 / d2) is 3.5 or less, and (S2 / s2) is 2 or more. Therefore, the sensitivity of the change in the amplitude of the ultrasonic vibration of the ultrasonic bonding tip is improved in response to the change in force acting on the ultrasonic bonding tip from one workpiece to the other workpiece, both before and after the completion of ultrasonic bonding of the two workpieces in contact with the ultrasonic bonding tip. On the other hand, (D2 / d2) is 1.5 or more, and (S2 / s2) is 7 or less. Therefore, the ultrasonic vibration of the ultrasonic bonding tip is efficiently transmitted to one workpiece, thereby improving the bonding efficiency between the two workpieces.

[0023] Therefore, it is possible to accurately determine whether the bonding is complete or not based on the changes in the values ​​of specified parameters, such as the amplitude of ultrasonic vibration of the ultrasonic bonding tip, which change according to the progress of bonding between the workpiece and the other workpiece. If the determination result indicates that the bonding between the workpiece and the other workpiece is complete, the ultrasonic vibration of the ultrasonic bonding tip is stopped, and as a result, the period during which the ultrasonic bonding tip is vibrating can be appropriately controlled from the viewpoint of improving the quality of bonding between the workpiece and the other workpiece.

[0024] An ultrasonic bonding apparatus according to the first aspect of the present invention is A vibration element that induces composite vibrations by combining longitudinal and torsional vibrations, A first aspect of the present invention is an ultrasonic bonding tip, An ultrasonic bonding apparatus comprising a control device for controlling the combined vibration of the aforementioned vibration element, The ultrasonic bonding tip is in contact with one workpiece, and the device includes a designated sensor that outputs a signal corresponding to a value of a designated parameter that changes according to the progress of bonding of one workpiece to the other workpiece. The control device determines, based on the output signal of the designated sensor, whether the joining of one workpiece and the other workpiece has been completed, and stops the combined vibration of the vibration element if it determines that the joining of one workpiece and the other workpiece has been completed.

[0025] With the ultrasonic bonding apparatus of this configuration, it is possible to accurately determine whether or not bonding is complete based on the changes in the values ​​of specified parameters that change according to the progress of bonding one workpiece and the other workpiece, such as the amplitude of ultrasonic vibration of the ultrasonic bonding tip as the first aspect of the present invention. If the determination result indicates that bonding of one workpiece and the other workpiece is complete, the ultrasonic vibration of the ultrasonic bonding tip is stopped, and as a result, the period during which the ultrasonic bonding tip is ultrasonically vibrating can be appropriately controlled from the viewpoint of improving the quality of bonding of one workpiece and the other workpiece.

[0026] An ultrasonic bonding apparatus according to a second aspect of the present invention is: A vibration element that induces composite vibrations by combining longitudinal and torsional vibrations, A second aspect of the present invention includes an ultrasonic bonding tip fixed to or detachably attached to the aforementioned vibrating element, An ultrasonic bonding apparatus comprising a control device for controlling the combined vibration of the aforementioned vibration element, The ultrasonic bonding tip is in contact with one workpiece, and the device includes a designated sensor that outputs a signal corresponding to a value of a designated parameter that changes according to the progress of bonding of one workpiece to the other workpiece. The control device determines, based on the output signal of the designated sensor, whether the joining of one workpiece and the other workpiece has been completed, and stops the combined vibration of the vibration element if it determines that the joining of one workpiece and the other workpiece has been completed.

[0027] According to the ultrasonic bonding apparatus with this configuration, it is possible to accurately determine whether the bonding is complete or not based on the changes in the values ​​of specified parameters that change according to the progress of bonding one workpiece and the other workpiece, such as the amplitude of ultrasonic vibration of the ultrasonic bonding tip as a second aspect of the present invention. If the determination result indicates that the bonding of one workpiece and the other workpiece is complete, the ultrasonic vibration of the ultrasonic bonding tip is stopped, and as a result, the period during which the ultrasonic bonding tip is ultrasonically vibrating can be appropriately controlled from the viewpoint of improving the quality of bonding of one workpiece and the other workpiece. [Brief explanation of the drawing]

[0028] [Figure 1] Diagram illustrating the configuration of an ultrasonic bonding device. [Figure 2] A diagram illustrating the configuration of an ultrasonic bonding chip as one embodiment of the present invention. [Figure 3] A flowchart illustrating the functions of an ultrasonic bonding device. [Figure 4] A diagram showing the changes in amplitude and power of an ultrasonic bonding tip (conventional). [Figure 5] A diagram illustrating the configuration of an ultrasonic bonding tip as another embodiment of the present invention. [Figure 6] An explanatory diagram illustrating the differences in amplitude change patterns due to differences in the configuration of ultrasonic bonding tips. [Modes for carrying out the invention]

[0029] (composition) The ultrasonic composite vibration device 1, shown in Figure 1 as a first embodiment of the present invention, is a component of an ultrasonic bonding device that joins workpieces W1 and W2, which are objects to be joined, such as metal plates, using ultrasonic composite vibration described later. The ultrasonic bonding device is used, for example, for electrodes of lithium-ion batteries and / or semiconductor elements, and for joining the same or different metals.

[0030] As shown in Figure 1, the ultrasonic composite vibration device 1 comprises a substantially cylindrical first vibration element 11, a substantially cylindrical, substantially cylindrical, or substantially bottomed cylindrical intermediate vibration element 10, and a substantially cylindrical or substantially bottomed cylindrical second vibration element 12. The first vibration element 11, the intermediate vibration element 10, and the second vibration element 12 constitute a "vibration element". The ultrasonic bonding device comprises the ultrasonic composite vibration device 1, a horn tip 40 (ultrasonic bonding tip), and an anvil 18.

[0031] The first vibration element 11 and the intermediate vibration element 10 are coaxially connected by a mechanical coupling mechanism (such as a bolt and / or clamp mechanism) in the middle or intermediate part of the ultrasonic composite vibration device 1. The intermediate vibration element 10 and the second vibration element 12 are coaxially connected by a mechanical coupling mechanism in the middle part of the ultrasonic composite vibration device 1. The first vibration element 11, the intermediate vibration element 10, and the second vibration element 12 may be integrally configured rather than being mechanically connected.

[0032] The intermediate vibration element 10 may be a component of the first vibration element 11. That is, the first vibration element 11 may be composed of two vibration elements. In this case, the first vibration element 11 and the intermediate vibration element 10 may be integrally configured rather than being mechanically connected. The intermediate vibration element 10 may be a component of the second vibration element 12. That is, the second vibration element 12 may be composed of two vibration elements. In this case, the second vibration element 12 and the intermediate vibration element 10 may be integrally configured rather than being mechanically connected.

[0033] As shown in Figure 1, the first vibrating element 11 is provided with a piezoelectric body 112 whose axial direction is the direction of piezoelectric polarization.

[0034] As shown in Figure 1, the intermediate vibration element 10 has a substantially annular plate-shaped intermediate flange 100 that extends radially around its entire circumference at an intermediate position in its axial direction. The intermediate vibration element 10 is configured to be clamped or supported around its entire circumference by a clamping mechanism (not shown) at least at the intermediate flange 100. The intermediate flange 100 may be omitted if it is guaranteed that the intermediate vibration element 10 will be supported by a mechanical support mechanism. As shown in Figure 1, the intermediate vibration element 10 is substantially cylindrical with an outer diameter that is substantially constant in the axial direction behind the intermediate flange 100 (to the left in Figure 1). As shown in Figure 1, the intermediate vibration element 10 is substantially cylindrical (a substantially frustoconical shape and a substantially cylindrical shape coaxially connected) with an outer diameter that continuously decreases towards the tip partway through the intermediate flange 100 (to the right in Figure 1).

[0035] As shown in Figure 1, the second vibration element 12 is provided with a frequency adjustment element 120, which is a roughly regular octagon with rounded corners, extending radially around its entire circumference at an intermediate position in its axial direction. The frequency adjustment element 120 adjusts the resonance frequencies of the longitudinal and torsional vibration components of the ultrasonic vibration.

[0036] As shown in Figure 1, the second vibration element 12 has a plurality of slits 124 formed on its outer surface behind the frequency adjustment element 120. The plurality of slits 124 may also be formed on the outer surface of the second vibration element 12 in front of the frequency adjustment element 120. The slits 124 extend diagonally when viewed from the side of the second vibration element 12, or extend axially while being displaced circumferentially in phase. The N (N=2, 3, ...) slits 124 may be arranged to have N rotational symmetry around the central axis of the second vibration element 12 (for example, N=8, 12, or 16).

[0037] As shown in Figure 1, the second vibrating element 12 is provided with a roughly octagonal tip portion 126 with rounded corners that extends radially around its entire circumference at its axial tip position. The tip portion 126 has multiple holes 128 (or through holes) formed at each of the circumferentially spaced locations. The N (N=2, 3, ...) holes 128 may be arranged to have N rotational symmetry (for example, N=4) around the central axis of the second vibrating element 12. Internal threads are provided on the inner surface of the holes 128.

[0038] The horn tip 40 has a base portion that is roughly frustoconical in shape and a tip portion that contacts the uppermost of the workpieces W1 and W2, workpiece W1. The male thread provided at the base end of the horn tip 40 is screwed into the female thread provided in the hole 128 of the tip portion 126 of the second vibrating element 12, thereby detachably fixing the horn tip 40 to the second vibrating element 12. By preparing horn tips 40 of various shapes, the horn tip 40 can be appropriately replaced depending on the type of metal to be joined.

[0039] The male thread of the balancer, which adjusts the phase difference between longitudinal and torsional vibrations at the tip 126 of the second vibrating element 12 and, consequently, at the horn tip 40, may be screwed into the female thread of the hole 128, thereby allowing the balancer to be detachably fixed to the tip 126 of the second vibrating element 12.

[0040] The anvil 18 is positioned perpendicular to the tip of the horn tip 40. For example, substantially flat workpieces W1 and W2 are placed on top of each other on the upper surface of the anvil 18. The anvil 18 may be configured to be passively or actively displaced up and down in response to the pressure on the horn tip 40 received through the workpieces W1 and W2.

[0041] As shown in Figure 1, the ultrasonic bonding apparatus further comprises a control device 20, a high-frequency power supply device 21, a pressurizing device 22, a state sensor 24, and an interface device 26.

[0042] The high-frequency power supply unit 21 is configured to excite the first vibration element 11 in the axial direction by applying a high-frequency AC voltage to the piezoelectric body 112 of the first vibration element 11 in accordance with the power supplied from the commercial power supply (not shown). The pressurizing device 22 is equipped with a pressurizing block and is configured to apply pressure from the horn tip 40 to the workpieces W1 and W2 by displacing a support mechanism such as a clamp mechanism that supports the intermediate vibration element 10 with the pressurizing block. The state sensor 24 includes a stroke sensor that outputs a signal corresponding to the amount of displacement of the pressurizing block that constitutes the pressurizing device 22, as well as an amplitude sensor that outputs a signal corresponding to the amplitude of the horn tip 40 (corresponding to a specified parameter). The amplitude sensor may be a sensor module composed of an imaging device and a device that calculates the amplitude by analyzing the image acquired through the imaging device.

[0043] The interface device 26 is configured, for example, as a display, which displays or outputs the displacement amount and / or pressure of the pressurizing block in response to the output signal of the state sensor 24, etc. The display may be a touch panel display and may be configured to accept setting operations that allow the user to directly or indirectly specify parameters, such as one of several bonding modes that define the time series pattern of the target pressure.

[0044] The control device 20 is composed of a microcomputer, and by extension, an arithmetic processing unit (CPU, microprocessor, processor core, etc.) and a storage device (ROM, RAM, etc.). The control device 20 is configured to control the displacement operation of the pressurizing block by the pressurizing device 22 based on the time series of the displacement amount of the pressurizing block, which is represented by the output signal of the stroke sensor that constitutes the state sensor 24. The control device 20 is configured to control the power supplied to the piezoelectric body 112 based on the amplitude of the horn tip 40 (corresponding to a specified parameter), which is represented by the output signal of the amplitude sensor that constitutes the state sensor 24, and thereby control the ultrasonic vibration power of the vibration elements (first vibration element 11, intermediate vibration element 10, and second vibration element 12) and the ultrasonic vibration power of the horn tip 40. As a state sensor 24, a pressure sensor is provided that outputs a signal corresponding to the pressure acting on the intermediate vibration element 10 from the pressurizing block of the pressurizing device 22 (~pressure applied by the horn tip 40 to workpieces W1 and W2). Based on the output signal of the pressure sensor, the control device 20 may control the time series of the pressure to be constant or controlled in a specified manner.

[0045] As shown in Figure 2, the horn tip 40 comprises a mounting portion 41, a base portion 42, and a rod portion 44. The mounting portion 41 is formed in a substantially cylindrical shape, and a male thread is formed on its outer surface that screws into a female thread formed in a hole 128 of the tip portion 126 of the second vibrating element 12. The base portion 42 is coaxially continuous with the mounting portion 41 and has a substantially cylindrical first portion with a larger diameter than the mounting portion 41, and a substantially frustoconical second portion having a lower base surface with substantially the same diameter as the first portion. The rod portion 44 is coaxially continuous with the second portion of the base portion 42 and is formed in a substantially cylindrical shape with a smaller diameter than the upper base surface of the second portion.

[0046] The mounting portion 41 may be omitted, and a screw hole may be formed extending axially from the end face of the first portion of the base portion 42. The horn tip 40 may be attached to the second vibrating element 12 by screwing a bolt or male thread, which is screwed or fixed to the tip portion 126 of the second vibrating element 12, into the female thread of the screw hole.

[0047] The rod portion 44 is formed such that the ratio (D1 / d1) of the axial length D1 of the rod portion 44 to the maximum distance d1 (radius of the circular cross-section) from the center of the substantially circular cross-section having the largest cross-sectional area to the periphery of the substantially circular cross-section is within the range of 40 to 100, in a direction perpendicular to the axial direction (or longitudinal direction) of the rod portion 44. For example, if the axial length D1 of a substantially cylindrical rod portion 44 is 60 mm, the radius of the rod portion 44 is designed to be within the range of (60 / 100) to (60 / 40) mm = 0.6 to 1.5 mm.

[0048] The horn tip 40 is formed such that the ratio (S1 / s1) of the maximum cross-sectional area S1 of the base portion 42 in the direction perpendicular to the axial direction to the maximum cross-sectional area s1 of the rod portion 44 in the direction perpendicular to the axial direction falls within the range of 6.2 to 52.9. In this embodiment, since the rod portion 44 is substantially cylindrical, the maximum cross-sectional area S1 is πr using its radius r. 2 It is expressed as follows, and since the base 42 is a combination of a roughly cylindrical first part and a roughly frustoconical second part, the maximum cross-sectional area s1 is πR using the diameter R of the first part. 2 Since it can be expressed as, the ratio (S1 / s1) = (r 2 / R 2 ) falls within the range of 6.2 to 52.9 (where (r / R) is in the range of 2.89 to 7.27).

[0049] The base portion 42 may have a shape different from the combination of a roughly cylindrical first portion and a roughly frustoconical second portion. For example, the base portion 42 may be roughly cylindrical, roughly prismatic, roughly frustoconical, or roughly frustoconical. The cross-sectional shape of the rod portion 44 may be a roughly circular shape, as well as a roughly elliptical shape, a roughly rectangular shape (square, parallelogram, etc.), a roughly polygonal shape (for example, a regular M-gon (e.g., M=8~16), a roughly star-shaped M-gon (e.g., M=4~16)), and various other shapes. The rod portion 44 may be formed such that the cross-sectional shape in the axial direction changes in a various order along the axial direction, as well as a roughly circular shape, as well as a roughly elliptical shape, a roughly rectangular shape (square, parallelogram, etc.), a roughly polygonal shape (for example, a regular M-gon, a roughly star-shaped M-gon), and various other shapes.

[0050] The horn tip 40 may be configured such that the ratio of the resonant frequency f2 of the horn tip 40 alone to the resonant frequency f1 of the entire vibration system including the horn tip 40 (f2 / f1) when the horn tip 40 is resonating at its resonant frequency while not in contact with the workpiece W1 falls within the range of 1.005 to 1.07. With this configuration, it is possible to accurately determine whether the joining of one workpiece W1 and the other workpiece W2 is complete, depending on how the values ​​of specified parameters, such as the amplitude of ultrasonic vibration of the horn tip 40, change according to the progress of the joining process. If the determination result indicates that the joining of one workpiece W1 and the other workpiece W2 is complete, the ultrasonic vibration of the horn tip 40 is stopped, and as a result, the period during which the horn tip 40 is ultrasonically vibrating can be appropriately controlled from the viewpoint of improving the quality of the joining of workpiece W1 and the other workpiece W2.

[0051] When the horn tip 40 is not in contact with the workpiece W1, the free end of the rod portion 44 becomes an antinode of the standing wave of the ultrasonic composite vibration. Therefore, the phase difference between the free end of the rod portion 44 and the position of the node of the standing wave closest to the free end is (π / 2). In Figure 2, the standing wave of the ultrasonic composite vibration when the horn tip 40 is in contact with the workpiece W1 and resonating at the resonant frequency is shown by a solid line (the amplitude represents the amplitude in the direction perpendicular to the axial direction or the displacement of the horn tip 40). In Figure 2, the changes in the bending angle of the horn tip 40 are shown by a dashed line. The contact state (contact pressure, etc.) between the horn tip 40 and the workpiece W1 may be adjusted so that the phase difference of the standing wave between the base end of the rod portion 44 and the position of the node closest to the free end of the standing wave falls within the range of 0.10π to 0.21π.

[0052] A reference amplitude A0 is set (Figure 3 / STEP01). For example, the reference amplitude A0 may be directly or indirectly specified by the user through a touch panel display constituting the interface device 26, such as one of several junction modes in which the reference amplitude A0 is determined.

[0053] The pressurizing device 22 moves the first vibration element 11, the intermediate vibration element 10, the second vibration element 12, and the horn tip 40 downward (Figure 3 / STEP02). The pressure P received by the tip of the horn tip 40 (the free end of the rod portion 44) from the workpieces W1 and W2 is measured based on the output signal of the pressure sensor constituting the state sensor 24 (Figure 3 / STEP04). When the tip of the horn tip 40 is separated from the workpiece W1, P=0, and when it comes into contact with the workpiece W1, P>0.

[0054] It is determined whether the pressure P acting on the horn tip 40 is equal to or greater than the specified pressure P0 (Figure 3 / STEP06). If the determination result is negative (Figure 3 / STEP06...NO), the pressurizing device 22 moves the first vibration element 11, the intermediate vibration element 10, the second vibration element 12, and the horn tip 40 downward (Figure 3 / STEP02). This adjusts the vertical position of the horn tip 40, and consequently the static pressure applied from the tip of the horn tip 40 to the workpieces W1 and W2, so that it falls within the specified static pressure range (for example, 200N to 800N).

[0055] If the judgment result is positive (Figure 3 / STEP06...YES), ultrasonic vibration is generated in the vibrating element (Figure 3 / STEP08). Specifically, in response to power being supplied to the high-frequency power supply 21 from the commercial power supply (not shown), the high-frequency power supply 21 applies a high-frequency AC voltage to the piezoelectric body 112 of the first vibrating element 11. As a result, the first vibrating element 11 vibrates in its axial direction at, for example, about 20 kHz, generating ultrasonic vibration. The ultrasonic vibration is transmitted from the first vibrating element 11 to the intermediate vibrating element 10 in its axial direction, and the amplitude of the ultrasonic vibration is amplified. Furthermore, the amplified ultrasonic vibration is transmitted from the intermediate vibrating element 10 to the second vibrating element 12 in its axial direction.

[0056] In this way, a portion of the longitudinal vibration component (the axial component of the second vibration element 12) of the ultrasonic vibration transmitted to the second vibration element 12 is converted into a torsional vibration component by the multiple slits 124 formed on the outer surface of the second vibration element 12. The combined vibration resulting from the combination of the longitudinal vibration component and the torsional vibration component is then transmitted to the horn tip 40 fixed to the tip 126 of the second vibration element 12.

[0057] In response, the tip of the horn tip 40 is displaced or vibrates horizontally, tracing a circular or elliptical orbit. As a result, as schematically shown in Figure 4, the amplitude and ultrasonic vibration power of the horn tip 40 gradually increase from the vibration start time t=t0. During this time, impurities on the contact surfaces of workpieces W1 and W2 are removed, and plastic deformation of the contact surfaces of workpieces W1 and W2 may be promoted. Then, as shown in Figure 4, after the rate of increase of the amplitude and ultrasonic vibration power of the horn tip 40 decreases significantly at time t=t1, the amplitude and ultrasonic vibration power of the horn tip 40 gradually increase. This is because the oxide film and other deposits on the metals constituting the joint surfaces of workpiece W1 and workpiece W2 are removed, clean and activated metal atoms appear on the joint surface, and the temperature rise due to frictional heat makes the atomic motion more active, generating mutual attractive forces between atoms.

[0058] In this process, the amount of pressure applied to the workpieces W1 and W2 by the horn tip 40 and / or the static pressure applied to the workpieces W1 and W2 are adjusted, and a compound vibration is applied to one of the workpieces W1 and W2, thereby enabling solid-state bonding of the workpieces W1 and W2.

[0059] The amplitude sensor constituting the state sensor 24 optically measures the amplitude A at a specified location on the horn tip 40 (for example, a location with a relatively large amplitude) (Figure 3 / STEP 10). It is determined whether the time derivative δA (= current amplitude A(k) - previous amplitude A(k-1)) of the amplitude A of the horn tip 40 is negative and whether the amplitude A is less than or equal to the reference amplitude A0 (Figure 3 / STEP 12). Alternatively, it may be determined whether the amplitude A has decreased by the reference amplitude A0 (or a reference ratio based on the maximum value) using the maximum value at which the amplitude A began to decrease as a reference.

[0060] If the judgment result is negative (Figure 3 / STEP12...NO), ultrasonic vibrations are continuously generated in the vibrating element (Figure 3 / STEP08). On the other hand, if the judgment result is positive (Figure 3 / STEP12...YES), the generation of ultrasonic vibrations in the vibrating element is stopped (Figure 3 / STEP14). For example, as shown in Figure 4, after time t=t2 when the amplitude of the horn tip 40 changes from increasing to decreasing and becomes less than or equal to the reference amplitude A0, the ultrasonic power of the horn tip 40 is controlled to become 0 with a slight response delay.

[0061] (effect) In the ultrasonic composite vibration device 1 with the above configuration, the ratio of the axial length D1 of the rod portion 44 to the maximum distance d1 (radius of the substantially circular cross-section) from the center of the cross-section having the maximum cross-sectional area to the periphery of the cross-section (in the direction perpendicular to the axial direction of the substantially cylindrical rod portion 44) (D1 / d1) is 40 or more. The ratio of the maximum cross-sectional area S1 of the base portion 42 in the direction perpendicular to the axial direction to the maximum cross-sectional area s1 of the rod portion 44 in the direction perpendicular to the axial direction (S1 / s1) is 52.9 or less. Therefore, before and after the completion of ultrasonic bonding of workpieces W1 and W2 in contact with the horn tip 40, the sensitivity of the change in the amplitude A of the ultrasonic vibration of the horn tip 40 in response to the change in the force acting on the horn tip 40 from one of the workpieces W1 is improved.

[0062] On the other hand, the ratio of the axial length D1 of the rod portion 44 to the maximum distance d1 from the center of the cross-section with the maximum cross-sectional area to the peripheral edge of the cross-section (D1 / d1) in the direction perpendicular to the axial direction of the substantially cylindrical rod portion 44 is 100 or less. Also, the ratio of the maximum cross-sectional area S1 of the base portion 42 in the direction perpendicular to the axial direction to the maximum cross-sectional area s1 of the rod portion 44 in the direction perpendicular to the axial direction (S1 / s1) is 6.2 or more. As a result, the ultrasonic vibrations of the horn tip 40 are efficiently transmitted to one workpiece W1 and the other W2, thereby improving the joining efficiency of the workpieces W1 and W2.

[0063] Therefore, it is possible to accurately determine whether the joining is complete or not based on the changes in the values ​​of specified parameters, such as the amplitude A of the ultrasonic vibration of the horn tip 40, which change according to the progress of joining one workpiece W1 and the other workpiece W2 (see the amplitude of the horn tip in Figure 3 / STEP12 and Figure 4). If the determination result indicates that the joining of one workpiece W1 and the other workpiece W2 is complete, the ultrasonic vibration of the horn tip 40 can be stopped (see the ultrasonic vibration power from time t=t2 onwards in Figure 3 / STEP12...YES → STEP14 and Figure 4). As a result, the period during which the horn tip 40 is ultrasonically vibrated can be appropriately controlled from the viewpoint of improving the quality of the joining of one workpiece W1 and the other workpiece W2.

[0064] (Other embodiments of the present invention) In the above embodiment, the amplitude A of the horn tip 40 was measured as a specified parameter that changes according to the progress of joining one workpiece W1 and the other workpiece W2. In other embodiments, the axial displacement, displacement velocity, and / or displacement acceleration of a vibrating element (e.g., a second vibrating element 12) may be measured as specified parameters.

[0065] As shown in Figure 5, in another embodiment of the present invention, the horn tip 40 has a single designated portion 440 in the middle along its axial direction, which is locally reduced in diameter compared to the base portion 441 and the tip portion 442. The base portion 441 is formed in a substantially cylindrical shape. The tip portion 442 is formed in a shape in which a first portion, which is substantially cylindrical with a smaller diameter than the base portion 441, and a second portion, which is substantially frustoconical and has a lower base surface of substantially the same diameter as the first portion, are combined so as to be coaxially continuous. The designated portion 440 is formed in a substantially cylindrical shape with a smaller diameter than the first portion of the tip portion 442. A mounting portion 41 may be provided on the base end side of the base portion 441, similar to the embodiment described above.

[0066] The designated portion 440 is roughly drum-shaped, gradually decreasing in diameter from one end on the base end 441 side to the other end on the tip end 442 side (in the axial or longitudinal direction of the horn tip 40), showing a minimum diameter in the intermediate region, and then gradually increasing in diameter. It may be formed in a roughly drum shape such that it has the minimum diameter of the horn tip 40 in at least the intermediate region. In this case, the designated portion 440 may have approximately the same diameter as or a smaller diameter than the base end 441 at one end, and approximately the same diameter as or a smaller diameter than the first part of the tip end 442 at the other end. Also, the second derivative of the diameter (=2r) with respect to the axial direction (x direction) of the horn tip 40 (=2(d) 2 r / dx 2 The specified portion 440 may be defined as the section from where )) changes from negative to positive to where it changes from positive to negative.

[0067] The shapes of the base portion 441, the designated portion 440, and the tip portion 442 may be varied. For example, each of the base portion 441, the designated portion 440, and the tip portion 442 may be approximately cylindrical, approximately prismatic, approximately frustoconical, approximately frustoconical, or approximately frustoconical, or a combination thereof. Each of the base portion 441, the designated portion 440, and the tip portion 442 may be formed such that the axial cross-sectional shape changes in various order along the axial direction to various shapes, such as approximately circular, approximately elliptical, approximately rectangular (square, parallelogram, etc.), approximately polygonal (e.g., regular M-gon (e.g., M=8~16), approximately star-shaped M-gon (e.g., M=4~16)).

[0068] The ratio of the axial length D2 of the horn tip 40 to the axial length d2 of a single designated portion 440 (D2 / d2) is in the range of 1.5 to 3.5 (preferably 1.8 to 3.0, 2.0 to 3.0, or 2.2 to 2.8). The ratio of the maximum cross-sectional area S2 of the horn tip 40 to the minimum cross-sectional area s2 of the designated portion 440 in a cross section perpendicular to the axial direction (S2 / s2) is in the range of 2 to 7 (preferably 2.5 to 6.2, 3.2 to 5.5, or 3.8 to 4.6). In this embodiment, since the designated portion 440 is substantially cylindrical, the minimum cross-sectional area s2 is πq using its radius q. 2It is expressed as follows. In this embodiment, since the cross-sectional area of the horn tip 40 is maximized at the cross-section of the substantially cylindrical base end portion 441, the maximum cross-sectional area S2 of the horn tip 40 is πQ using the radius Q of the base end portion 441. 2 It is expressed as follows. Therefore, the ratio (S2 / s2) of the maximum cross-sectional area S2 of the horn tip 40 to the minimum cross-sectional area s2 of the designated portion 440 is (Q 2 / q 2 ), which is included in the range of 2 to 7 ((Q / q) is in the range of 1.14 to 2.65).

[0069] According to the horn tip 40 having such a configuration, (D2 / d2) is 3.5 or less and (S2 / s2) is 2 or more. Therefore, before and after the completion of the ultrasonic bonding of one work W1 and the other work W2 with which the horn tip 40 is in contact, the sensitivity of the change in the amplitude of the ultrasonic vibration of the horn tip 40 in response to the change in the force acting on the horn tip 40 from the one work W1 is improved. On the other hand, (D2 / d2) is 1.5 or more and (S2 / s2) is 7 or less. Therefore, the ultrasonic vibration of the horn tip 40 is efficiently transmitted to the one work W1, and thus the bonding efficiency between the one work W1 and the other work W2 is improved.

[0070] Therefore, whether or not the bonding is completed can be accurately determined according to the change mode of the value of the designated parameter that changes according to the progress of the bonding of the one work W1 and the other work W2, such as the amplitude A of the ultrasonic vibration of the horn tip 40 (refer to the amplitude of the horn tip in FIG. 3 / STEP12 and FIG. 4). When the determination result indicates that the bonding of the one work W1 and the other work W2 is completed, the ultrasonic vibration of the horn tip 40 can be stopped (refer to FIG. 3 / STEP12‥YES→STEP14 and the ultrasonic vibration power after the time t = t2 in FIG. 4). As a result, the period during which the horn tip 40 is ultrasonically vibrated can be appropriately controlled from the viewpoint of improving the quality of the bonding of the one work W1 and the other work W2.

[0071] As shown in Figure 2, the outer shape of the horn tip 40 has a step at the point where the base 42 and the rod portion 44 are connected, due to differences in diameter or cross-sectional area. If this step, and consequently the change in the cross-sectional area of ​​the horn tip 40, is excessively large, the amplitude (amount of displacement in the direction perpendicular to the axial direction) at the point where the rod portion 44 is connected to the base 42 may become excessively large. This not only increases the likelihood of damage to the horn tip 40 at this point, but also may lead to an unstable vibration state. For this reason, it is preferable that the horn tip 40 be formed integrally and that its outer shape be designed to reduce the change in cross-sectional area at the point where the base 42 and the rod portion 44 are connected, but this would increase the manufacturing cost of the horn tip.

[0072] From the perspective of reducing manufacturing costs, the horn tip 40 is composed of a base portion 42 and a rod portion 44 that are formed separately. The rear end of the rod portion 44 is press-fitted into a hole formed in the tip of the rod portion 42, or the male thread formed on the rear end of the rod portion 44 is screwed into the female thread formed in the hole at the tip of the rod portion 42.

[0073] To solve the above problem, the difference in materials constituting the base portion 42 and the rod portion 44 allows for the sound velocity c in the base portion 42. s42 The speed of sound c in the rod section 44 is greater than s44 It is preferable that the configuration be such that the speed of sound c is large. s (The speed of longitudinal vibration of the rod-shaped member) is (E / ρ) 1 / 2 Since it is defined by (E: Young's modulus, ρ: specific gravity), the Young's modulus E of the material constituting the base 42 42 and specific gravity ρ 42 And the Young's modulus E of the material constituting the rod portion 44 44 and specific gravity ρ 44 And, but, (E 42 / ρ 42 ) 1 / 2 <(E 44 / ρ 44 ) 1 / 2It is preferable that the materials (for example, metal materials such as stainless steel) be selected in such a large-small-small relationship. For example, it is preferable that stainless steel is used as the material constituting the base portion 42, and an alloy such as a tungsten alloy is used as the material constituting the rod portion 44.

[0074] Figure 6 shows c s42 The speed of sound c in the rod section 44 is greater than s44 The amplitude of the rod portion 44 (displacement in a direction perpendicular to the axial direction) when the materials constituting the base portion 42 and the rod portion 44 are different is shown by the solid line. When the materials constituting the base portion 42 and the rod portion 44 are the same (c s42 =c s44 The amplitude of the rod portion 44 in the case of ( ) is shown by the dashed line. It can be seen that the rate of increase in the axial direction of the displacement at the rear end of the rod portion 44 is smaller in the former case than in the latter case, and consequently, the possibility of damage to the horn tip 40 is reduced. Materials with a high velocity of sound usually have a high Young's modulus E, so the amplitude of the rod portion 44 is also reduced, making it possible to maintain a stable vibration state without the vibration deviating from the central axis. [Explanation of Symbols]

[0075] 1. Ultrasonic combined vibration device 10. Intermediate vibration element 100...Intermediate flange 11. First vibration element 112. Piezoelectric material 12. Second vibration element 120...Frequency adjustment element 121...Cylindrical part 122...Cylindrical part 124... Slit 126‥Tip 128... Hole 18... Anvil 20. Control device 21‥High frequency power supply equipment 22. Pressurizing device 24. Stroke sensor 26. Interface device. 40. Horn tip (tip for ultrasonic bonding) 41... Mounting part 42‥Base 44...Rod section 440‥Specified part 441‥Proximal end 442‥Tip W1... One side of the work W2...the other workpiece.

Claims

1. An ultrasonic bonding tip for coupling with an ultrasonic vibration device equipped with a vibration element that induces composite vibration by combining longitudinal and torsional vibrations, It has a base portion that is detachably attached to the vibrating element, and a rod portion that extends continuously in the axial direction from the base portion, The rod portion is formed such that, in the direction perpendicular to the axial direction, the ratio of the axial length D1 of the rod portion to the maximum distance d1 from the center of the cross-section having the largest cross-sectional area to the peripheral edge of said cross-section (D1 / d1) falls within the range of 30 to 120, and An ultrasonic bonding tip is formed such that, when the ultrasonic bonding tip is not in contact with one of the workpieces, the ratio f2 / f1 of the resonance frequency f2 of the ultrasonic bonding tip alone to the resonance frequency f1 of the entire vibration system including the ultrasonic bonding tip falls within the range of 1.005 to 1.

07.

2. In the ultrasonic bonding tip described in claim 1, The aforementioned vibration element is a vibrating body that induces the aforementioned composite vibration, and is configured such that a vibration generating element and a vibration transmitting element are coupled and arranged coaxially. The base is configured to be connected to the coupling portion provided on the vibration transmission element. Ultrasonic bonding tip.

3. In the ultrasonic bonding tip described in claim 1, The ratio (S1 / s1) of the maximum cross-sectional area S1 of the base portion in the direction perpendicular to the axial direction to the maximum cross-sectional area s1 of the rod portion in the direction perpendicular to the axial direction is formed to fall within the range of 6.2 to 52.

9. Ultrasonic bonding tip.

4. In the ultrasonic bonding tip according to either claim 1 or 2, The base is formed such that the cross-sectional area or the maximum distance to the peripheral edge of the cross-section in the direction perpendicular to the axial direction decreases as it approaches the rod portion. Ultrasonic bonding tip.

5. In the ultrasonic bonding tip according to either claim 1 or 2, Due to the difference in materials constituting the base and the rod, the speed of sound in the rod is greater than the speed of sound in the base. Ultrasonic bonding tip.

6. An ultrasonic bonding tip, which is coupled to an ultrasonic vibration device equipped with a vibration element that induces composite vibration by combining longitudinal and torsional vibrations, and is formed to extend in the axial direction, Regarding the cross-section of the ultrasonic bonding tip perpendicular to the axial direction, the ultrasonic bonding tip has a single designated portion that is locally tapered in the middle portion with respect to the axial direction. The ratio (D2 / d2) of the axial length D2 of the ultrasonic bonding tip to the axial length d2 of the single designated portion is within the range of 1.5 to 3.5, and The ratio (S2 / s2) of the maximum cross-sectional area S2 of the ultrasonic bonding tip to the minimum cross-sectional area s2 of the single designated portion in a cross section perpendicular to the axial direction is formed to fall within the range of 2 to 7, and When the ultrasonic bonding tip is not in contact with one of the workpieces, the ratio f2 / f1 of the resonance frequency f2 of the ultrasonic bonding tip alone to the resonance frequency f1 of the entire vibration system including the ultrasonic bonding tip is formed to fall within the range of 1.005 to 1.

07. Ultrasonic bonding tip.

7. In the ultrasonic bonding tip described in claim 6, The aforementioned vibration element is a vibrating body that induces the aforementioned composite vibration, and is configured such that a vibration generating element and a vibration transmitting element are coupled and arranged coaxially. The ultrasonic bonding tip is configured to be coupled to the coupling portion provided on the vibration transmission element. Ultrasonic bonding tip.

8. A vibration element that induces composite vibrations by combining longitudinal and torsional vibrations, Ultrasonic bonding tip, An ultrasonic bonding apparatus comprising a control device for controlling the combined vibration of the aforementioned vibration element, The ultrasonic bonding tip is in contact with one workpiece, and the device includes a designated sensor that outputs a signal corresponding to a value of a designated parameter that changes according to the progress of bonding of one workpiece to the other workpiece. The aforementioned ultrasonic bonding tip is It has a base that is fixed to or detachably attached to the vibrating element, and a rod portion that extends continuously in the axial direction from the base, The rod portion is formed such that, in the direction perpendicular to the axial direction, the ratio of the axial length D1 of the rod portion to the maximum distance d1 from the center of the cross-section having the largest cross-sectional area to the peripheral edge of said cross-section (D1 / d1) falls within the range of 30 to 120, and When the ultrasonic bonding tip is not in contact with one of the workpieces, the ratio f2 / f1 of the resonance frequency f2 of the ultrasonic bonding tip alone to the resonance frequency f1 of the entire vibration system including the ultrasonic bonding tip is formed to fall within the range of 1.005 to 1.

07. The control device determines, based on the output signal of the designated sensor, whether the joining of one workpiece and the other workpiece has been completed, and if it determines that the joining of one workpiece and the other workpiece has been completed, it stops the combined vibration of the vibration element. Ultrasonic bonding equipment.

9. A vibration element that induces composite vibrations by combining longitudinal and torsional vibrations, An ultrasonic bonding tip fixed to or detachably attached to the aforementioned vibrating element, An ultrasonic bonding apparatus comprising a control device for controlling the combined vibration of the aforementioned vibration element, The ultrasonic bonding tip is in contact with one workpiece, and the device includes a designated sensor that outputs a signal corresponding to a value of a designated parameter that changes according to the progress of bonding of one workpiece to the other workpiece. The aforementioned ultrasonic bonding tip is Regarding the cross-section of the ultrasonic bonding tip perpendicular to the axial direction, the ultrasonic bonding tip has a single designated portion that is locally tapered in the middle portion with respect to the axial direction. The ratio (D2 / d2) of the axial length D2 of the ultrasonic bonding tip to the axial length d2 of the single designated portion is within the range of 1.5 to 3.

5. The ratio (S2 / s2) of the maximum cross-sectional area S2 of the ultrasonic bonding tip to the minimum cross-sectional area s2 of the single designated portion in a cross section perpendicular to the axial direction is within the range of 2 to 7, and When the ultrasonic bonding tip is not in contact with one of the workpieces, the ratio f2 / f1 of the resonance frequency f2 of the ultrasonic bonding tip alone to the resonance frequency f1 of the entire vibration system including the ultrasonic bonding tip is formed to fall within the range of 1.005 to 1.

07. The control device determines, based on the output signal of the designated sensor, whether the joining of one workpiece and the other workpiece has been completed, and if it determines that the joining of one workpiece and the other workpiece has been completed, it stops the combined vibration of the vibration element. Ultrasonic bonding equipment.

10. An ultrasonic bonding method for bonding one workpiece to another, using an ultrasonic bonding apparatus comprising a vibrating element that induces a composite vibration by combining longitudinal and torsional vibrations, and an ultrasonic bonding tip that is fixed to or detachably attached to the vibrating element, The ultrasonic bonding tip is in contact with the workpiece to be bonded, and a designated sensor is provided that outputs a signal corresponding to the value of a designated parameter that changes according to the progress of bonding one workpiece to the other workpiece. It has a base that is fixed to or detachably attached to the vibrating element, and a rod portion that extends continuously in the axial direction from the base, The rod portion is formed such that, in a direction perpendicular to the axial direction, the ratio of the axial length D1 of the rod portion to the maximum distance d1 from the center of the cross-section having the maximum cross-sectional area to the peripheral edge of said cross-section (D1 / d1) is 40 ≤ (D1 / d1) ≤ 100, and when the ultrasonic bonding tip is not in contact with one of the workpieces, the ratio f2 / f1 of the resonance frequency f2 of the ultrasonic bonding tip alone to the resonance frequency f1 of the entire vibration system including the ultrasonic bonding tip falls within the range of 1.005 to 1.

07. The process involves determining whether the bonding between one workpiece and the other workpiece is complete, based on a signal corresponding to a value of a specified parameter that changes according to the progress of bonding of the one workpiece to the other workpiece, while the ultrasonic bonding tip is in contact with the one workpiece to be bonded. The step includes stopping the combined vibration of the vibration element when it is determined that the joining of one workpiece and the other workpiece has been completed. Ultrasonic bonding method.

11. An ultrasonic bonding method for bonding one workpiece to another, using an ultrasonic bonding apparatus comprising a vibrating element that induces a composite vibration by combining longitudinal and torsional vibrations, and an ultrasonic bonding tip that is fixed to or detachably attached to the vibrating element, With respect to a cross-section perpendicular to the axial direction, the ultrasonic bonding tip has a single designated portion that is locally tapered in the middle portion with respect to the axial direction. The ratio (D2 / d2) of the axial length D2 of the ultrasonic bonding tip to the axial length d2 of the single designated portion is within the range of 1.5 to 3.

5. The ratio (S2 / s2) of the maximum cross-sectional area S2 of the ultrasonic bonding tip to the minimum cross-sectional area s2 of the single designated portion in a cross section perpendicular to the axial direction is within the range of 2 to 7, and When the ultrasonic bonding tip is not in contact with one of the workpieces, the tip used as the ultrasonic bonding tip is formed such that the ratio f2 / f1 of the resonance frequency f2 of the ultrasonic bonding tip alone to the resonance frequency f1 of the entire vibration system including the ultrasonic bonding tip falls within the range of 1.005 to 1.

07. The process involves determining whether the bonding between one workpiece and the other workpiece is complete, based on a signal corresponding to a value of a specified parameter that changes according to the progress of bonding of the one workpiece to the other workpiece, while the ultrasonic bonding tip is in contact with the one workpiece to be bonded. The step includes stopping the combined vibration of the vibration element when it is determined that the joining of one workpiece and the other workpiece has been completed. Ultrasonic bonding method.

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