Ultrasonic bonding chip and ultrasonic bonding device using the same

Abstract

To provide an ultrasonic bonding chip capable of improving the quality of bonding of workpieces by ultrasonic composite vibration of a new form, and an ultrasonic bonding device using the same.SOLUTION: The ratio (E0 / E) of the Young modulus E0 (included in the range of 180-220 GPa) of a material constituting an adjustment member 400 to the Young modulus E (included in the range of 450-650 GPa) of a material constituting a first base portion 41 and a second base portion 42 of a horn chip 40, and a base portion constituted by the first base portion and the second base portion is included in the range of 0.28 to 0.49. When the ultrasonic composite vibration is applied to a first workpiece W1 and a second workpiece W2 in a direction (lateral direction) perpendicular to a pressing direction in a state where a distal end portion of the horn chip 40 (ultrasonic bonding chip) is pressed against the first workpiece W1, the adjustment member attached to the base portion so as to be sandwiched by the first base portion 41 and the second base portion 42 can be bent.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic bonding tip for bonding multiple workpieces made of various materials such as metals using ultrasonic vibrations, and to an ultrasonic bonding device and ultrasonic bonding method that use the ultrasonic bonding tip. [Background technology]

[0002] The present applicant has proposed a technique for joining workpieces using ultrasonic complex vibration (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7219495 Summary of the Invention [Problem to be solved by the invention]

[0004] Ultrasonic composite vibration is achieved by combining ultrasonic vibrations in two directions perpendicular to the axial direction of the ultrasonic bonding tip, but no consideration is given to ultrasonic vibrations in a direction parallel to the axial direction of the ultrasonic bonding tip.

[0005] Therefore, an object of the present invention is to provide an ultrasonic bonding tip that can improve the quality of bonding between workpieces by using a new type of ultrasonic complex vibration, and an ultrasonic bonding device using the same. [Means for solving the problem]

[0006] The ultrasonic bonding tip of the present invention is a base portion; a rod portion connected to the base portion; and an adjustment member removably attached to the base portion at an intermediate portion of the base portion in an axial direction thereof, The Young's modulus E of the material constituting the base is in the range of 450 to 650 GPa, The Young's modulus E0 of the material constituting the adjustment member is within the range of 180 to 220 GPa, The ratio (E0 / E) of the Young's modulus E0 of the material constituting the adjusting member to the Young's modulus E of the material constituting the base portion is within the range of 0.28 to 0.49.

[0007] In an ultrasonic bonding tip (hereinafter sometimes referred to simply as "tip") having this configuration, the ratio (E0 / E) of the Young's modulus E0 (180-220 GPa) of the material constituting the adjustment member to the Young's modulus E (450-650 GPa) of the material constituting the base is in the range of 0.28-0.49. As a result, when the tip of the rod portion of the tip is pressed against a workpiece and ultrasonic complex vibration is applied to the workpiece in a direction (lateral direction) perpendicular to the pressing direction (vertical direction), the adjustment member attached to the base can be deflected. As a result, the tip of the rod portion connected to the base can be ultrasonically vibrated not only in the lateral direction but also in the longitudinal direction.

[0008] In the early stages of joining multiple workpieces, the pressing force of the tip of the rod portion of the tip against the workpieces is intermittently increased due to the vertical ultrasonic vibrations, suppressing misalignment of the multiple workpieces. In the middle and final stages of joining multiple workpieces, part of the ultrasonic vibration energy applied from the rod portion of the tip to the multiple workpieces can be converted into vertical ultrasonic vibrations of the rod portion, preventing the tip from applying excessive horizontal ultrasonic vibrations to the multiple workpieces. As a result, the quality of the workpieces joined is improved.

[0009] Furthermore, multiple adjustment members with different specifications can be selectively attached to the base. This allows the vertical and horizontal (two-directional) ultrasonic complex vibrations applied from the tip to multiple workpieces to be adjusted. By selecting an appropriate adjustment member depending on the type of workpieces to be joined and / or the type of ultrasonic complex vibration device to which the tip is attached, the quality of the joining of the multiple workpieces can be improved.

[0010] In the ultrasonic bonding tip having the above configuration, The base portion is composed of a first base portion to which the rod portion is connected and a second base portion that is displaceable or detachable relative to the first base portion, The adjustment member is attached to the base in a state where it is sandwiched between the first base and the second base. It is preferable.

[0011] With this ultrasonic bonding tip, multiple adjustment members with different Young's moduli and / or thicknesses (the size of the base in the axial or longitudinal direction) can be selectively used. This allows the adjustment of the ultrasonic complex vibrations in the vertical and horizontal directions (two directions) applied from the tip to multiple workpieces. By selecting an appropriate adjustment member depending on the type of workpieces to be bonded and / or the type of ultrasonic complex vibration device to which the tip is attached, the quality of the bonding of the multiple workpieces can be improved.

[0012] In the ultrasonic bonding tip having the above configuration, When the adjustment member is attached to the base, the adjustment member has at least one of a portion that protrudes from the base and a portion that is recessed in a direction perpendicular to the axial direction of the base. It is preferable.

[0013] With this ultrasonic welding tip, the shape of the ultrasonic complex vibrations in the vertical and horizontal directions (two directions) applied to multiple workpieces can be adjusted by selectively using adjustment members with different outer shapes. By selecting an adjustment member with an appropriate outer shape depending on the type of workpieces to be welded and / or the type of ultrasonic complex vibration device to which the tip is attached, the quality of the welding of the multiple workpieces can be improved.

[0014] In the ultrasonic bonding tip having the above configuration, The base and the adjustment portion are each formed to have a columnar portion that has rotational symmetry about a central axis. It is preferable.

[0015] The ultrasonic bonding device of the present invention comprises: an ultrasonic vibrator that induces a composite vibration by combining longitudinal vibration and torsional vibration; The ultrasonic bonding tip of the present invention; and a control device for controlling the complex vibration of the ultrasonic vibrator.

[0016] With this ultrasonic bonding device, while the tip of the ultrasonic bonding tip is pressed against the workpiece, ultrasonic complex vibrations are applied to the workpiece in a direction perpendicular to the pressing direction (horizontal direction). This can deflect the adjustment member attached to the base. This allows the tip of the rod connected to the base to ultrasonically vibrate not only horizontally but also vertically. The vertical ultrasonic vibrations intermittently increase the pressing force of the tip of the tip against the workpieces in the early stages of joining multiple workpieces, thereby suppressing misalignment of the multiple workpieces. During the middle and final stages of joining multiple workpieces, a portion of the ultrasonic vibration energy applied to the multiple workpieces can be converted into vertical ultrasonic vibrations, preventing excessive horizontal ultrasonic vibrations from being applied to the multiple workpieces. As a result, the quality of the workpieces is improved.

[0017] The ultrasonic bonding method of the present invention comprises: An ultrasonic bonding method for bonding one workpiece and another workpiece using an ultrasonic bonding device including an ultrasonic vibrator that induces a composite vibration by combining longitudinal vibration and torsional vibration, and an ultrasonic bonding tip that is fixed to the ultrasonic vibrator or detachably attached to the ultrasonic vibrator, The ultrasonic bonding tip of the present invention is used, a step of determining whether or not the joining of the one workpiece and the other workpiece has been completed based on a signal corresponding to a value of a designated parameter that changes depending on the progress of joining of the one workpiece to the other workpiece while the ultrasonic joining tip is in contact with the one workpiece to be joined; and stopping the complex vibration of the ultrasonic vibrator when it is determined that the joining of the one workpiece and the other workpiece has been completed.

[0018] According to the ultrasonic bonding method of the present invention, whether the bonding is complete or not can be determined accurately based on the change in the value of a specified parameter, such as the amplitude of ultrasonic vibration of the ultrasonic bonding tip, which changes depending on the progress of the bonding of the first and second workpieces. If the determination result indicates that the bonding of the first and second workpieces 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 vibrated can be appropriately controlled from the perspective of improving the quality of the bonding of the first and second workpieces. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram illustrating the configuration of an ultrasonic bonding device according to an embodiment of the present invention. [Figure 2] 1 is a diagram illustrating the configuration of an ultrasonic bonding tip according to one embodiment of the present invention; [Figure 3] FIG. 2 is an explanatory diagram of the configuration of an ultrasonic bonding tip. [Figure 4] FIG. 3 is a cross-sectional view of a first embodiment of an adjustment member. [Figure 5] FIG. 10 is a cross-sectional view of a second embodiment of the adjustment member. [Figure 6] FIG. 10 is a cross-sectional view of a third embodiment of the adjustment member. [Figure 7] FIG. 10 is a diagram illustrating the configuration of an ultrasonic bonding tip according to another embodiment of the present invention. [Figure 8] 3 is a flowchart showing the function of the ultrasonic bonding device. DETAILED DESCRIPTION OF THE INVENTION

[0020] (composition) 1 includes an ultrasonic complex vibration device 10, a horn tip 40 (ultrasonic bonding tip), and an anvil 18. The anvil 18 may be omitted.

[0021] The ultrasonic complex vibration device 10 includes a first ultrasonic vibrator 110 having a substantially cylindrical shape, an intermediate ultrasonic vibrator 100 having a substantially cylindrical, cylindrical, or bottomed cylindrical shape, and a second ultrasonic vibrator 120 having a substantially cylindrical or bottomed cylindrical shape. The first ultrasonic vibrator 110, the intermediate ultrasonic vibrator 100, and the second ultrasonic vibrator 120 constitute "ultrasonic vibrators."

[0022] The first ultrasonic vibrator 110 and the intermediate ultrasonic vibrator 100 are coaxially connected by a mechanical connecting mechanism (such as a bolt and / or a clamp mechanism) at the middle or intermediate portion of the ultrasonic complex vibration device 10. The intermediate ultrasonic vibrator 100 and the second ultrasonic vibrator 120 are coaxially connected by a mechanical connecting mechanism at the middle portion of the ultrasonic complex vibration device 10. The first ultrasonic vibrator 110, the intermediate ultrasonic vibrator 100, and the second ultrasonic vibrator 120 may be integrally configured rather than being mechanically connected.

[0023] The intermediate ultrasonic vibrator 100 may be a component of the first ultrasonic vibrator 110. That is, the first ultrasonic vibrator 110 may be composed of two ultrasonic vibrators. In this case, the first ultrasonic vibrator 110 and the intermediate ultrasonic vibrator 100 may be integrally configured rather than being mechanically connected. The intermediate ultrasonic vibrator 100 may be a component of the second ultrasonic vibrator 120. That is, the second ultrasonic vibrator 120 may be composed of two ultrasonic vibrators. In this case, the second ultrasonic vibrator 120 and the intermediate ultrasonic vibrator 100 may be integrally configured rather than being mechanically connected.

[0024] As shown in FIG. 1, the first ultrasonic vibrator 110 is provided with a piezoelectric body 112 whose axial direction (direction parallel to the first axis) is the piezoelectric polarization direction.

[0025] As shown in FIG. 1, the intermediate ultrasonic vibrator 100 has a generally annular plate-shaped intermediate flange 102 formed at a central position in the axial direction, which extends radially over the entire circumference. The intermediate ultrasonic vibrator 100 is configured to be clamped or supported at least at the intermediate flange 102 by a clamping mechanism (not shown) around the entire circumference. If it is ensured that the intermediate ultrasonic vibrator 100 is supported by a mechanical support mechanism, the intermediate flange 102 may be omitted. As shown in FIG. 1, the intermediate ultrasonic vibrator 100 has a generally cylindrical shape with a generally constant outer diameter in the axial direction behind the intermediate flange 102 (leftward in FIG. 1). As shown in FIG. 1, the intermediate ultrasonic vibrator 100 has a generally cylindrical shape (a shape in which a generally truncated conical shape and a generally cylindrical shape are coaxially connected) with a generally constant outer diameter after continuously tapering partway toward the tip portion ahead of the intermediate flange 102 (rightward in FIG. 1).

[0026] 1, the second ultrasonic vibrator 120 is provided with a frequency adjustment element 122 in the shape of a substantially regular octagonal plate with rounded corners, which extends radially around the entire circumference at a midpoint in the axial direction of the second ultrasonic vibrator 120. The frequency adjustment element 122 adjusts the resonance frequencies of the longitudinal vibration component and the torsional vibration component of the ultrasonic vibration. The outer shape of the frequency adjustment element 122 may be a substantially circular, substantially elliptical, or substantially regular n-sided polygonal plate (e.g., n = 4, 6, 8, 12, 16, etc.) plate, columnar, or frustum shape, which shares a common central axis with the second ultrasonic vibrator 120, or any combination thereof.

[0027] 1, the second ultrasonic vibrating body 120 has a plurality of slits 124 formed on its outer surface behind the frequency adjustment element 122. A plurality of slits 124 may be formed on the outer surface of the second ultrasonic vibrating body 120 ahead of the frequency adjustment element 122. The slits 124 extend obliquely in the second ultrasonic vibrating body 120 when viewed from the side, or extend in the axial direction while being displaced in the circumferential direction in phase with each other. N (N=2, 3, ...) slits 124 may be arranged to have N-fold rotational symmetry (e.g., N=8, 12, or 16) around the central axis of the second ultrasonic vibrating body 120.

[0028] 1, the second ultrasonic vibrating body 12 is provided with a tip portion 126 of a generally regular octagonal shape with rounded corners that protrudes radially around the entire circumference at the tip position in the axial direction. Holes 128 (or through holes) are formed in the tip portion 126 at a plurality of locations spaced apart in the circumferential direction. The M (N=2, 3, ...) holes 128 may be arranged to have M-fold rotational symmetry (e.g., M=4) around the central axis of the second ultrasonic vibrating body 12. A female thread is provided on the inner surface of the hole 128.

[0029] Horn tip 40 has a substantially truncated cone-shaped base portion and a tip portion that abuts against workpiece W1, which is the uppermost of first workpiece W1 and second workpiece W2. A male thread provided at the base end of horn tip 40 is threaded into a female thread provided in hole 128 in tip portion 126 of second ultrasonic vibrator 12, thereby removably fixing horn tip 40 to second ultrasonic vibrator 12. Horn tips 40 of various shapes are available, so that horn tips 40 can be appropriately replaced depending on the type of metal to be joined, etc.

[0030] The balancer for adjusting the phase difference between the longitudinal vibration and the torsional vibration at the tip 126 of the second ultrasonic vibrator 12, and thus at the horn tip 40, may be removably fixed to the tip 126 of the second ultrasonic vibrator 12 by screwing the male thread of the balancer into the female thread of the hole 128.

[0031] The anvil 18 is disposed so as to face the tip of the horn tip 40 in the vertical direction. A first workpiece W1 and a second workpiece W2 as multiple workpieces are placed on the upper surface of the anvil 18. The anvil 18 may be configured to passively or actively displace up and down in response to the pressure of the horn tip 40 received through the first workpiece W1 and the second workpiece W2.

[0032] As shown in FIG. 1, the ultrasonic bonding apparatus according to one embodiment of the present invention further includes an operating device 20, a control device 22, a rotational driving device 220, a high-frequency power supply device 221, a translational driving device 222, and a status sensor 224.

[0033] The operation device 20 is configured, for example, by a display, and displays or outputs on the display the displacement amount of the pressure block and / or the time series of the pressure according to the output signal of the status sensor 224. The display may be configured by a touch panel display, and may be configured to accept a setting operation for allowing the user to directly or indirectly specify parameters, such as one of a plurality of bonding modes that determine a time series pattern of the target pressure.

[0034] The control device 22 is configured with a microcomputer, an arithmetic processing unit (CPU, microprocessor, processor core, etc.), and a storage device (memory such as ROM and RAM). The control device 22 is configured to control the displacement operation of the pressure block by the translation drive device 222 based on a time series of the displacement amount of the pressure block represented by the output signal of a stroke sensor that constitutes the status sensor 224. The control device 22 is configured to control the power supplied to the piezoelectric body 112 based on the amplitude (corresponding to the specified parameter) of the horn tip 40 represented by the output signal of an amplitude sensor that constitutes the status sensor 224, and thereby to control the ultrasonic vibration power of the ultrasonic vibrators (first ultrasonic vibrator 110, intermediate ultrasonic vibrator 100, and second ultrasonic vibrator 120) and the ultrasonic vibration power of the horn tip 40.

[0035] The high frequency power supply device 221 is configured to excite the first ultrasonic vibrator 110 in the axial direction by applying a high frequency AC voltage to the piezoelectric body 112 of the first ultrasonic vibrator 110 in accordance with power supplied from a commercial power source (not shown).

[0036] The translational drive device 222 is equipped with a pressure block and is configured to apply pressure from the horn tip 40 to the first workpiece W1 and the second workpiece W2 by displacing a support mechanism such as a clamping mechanism that supports the intermediate ultrasonic vibrator 100 using the pressure block.

[0037] The status sensor 224 includes a stroke sensor that outputs a signal corresponding to the displacement of the pressure block that constitutes the translational drive device 222, as well as an amplitude sensor that outputs a signal corresponding to the amplitude (corresponding to a specified parameter) of the horn tip 40. The amplitude sensor may be a sensor module composed of an imaging device and a device that calculates the amplitude by analyzing an image acquired through the imaging device. As the status sensor 224, a pressure sensor that outputs a signal corresponding to the pressure acting on the intermediate ultrasonic vibrator 100 from the pressure block of the translational drive device 222 (the pressure that the horn tip 40 applies to the first workpiece W1 and the second workpiece W2) may be provided, and the control device 22 may control the time series of the pressure to be constant or in a specified manner based on the output signal of the pressure sensor.

[0038] 2, horn tip 40 in one embodiment of the present invention includes a first base portion 41, a second base portion 42, an adjustment member 400, and a rod portion 44. First base portion 41 and second base portion 42 constitute the "base portion" of horn tip 40.

[0039] As shown in Fig. 2, the first base portion 41 is formed in a substantially cylindrical shape with a diameter φ1 (for example, φ1 = 20 to 40 [mm]) and a length L1 (for example, L1 = 30 to 60 [mm]). As shown in Fig. 3, the first base portion 41 is formed with an internal thread portion 410 extending in the axial direction from one end (the distal end (the left end in Figs. 2 and 3)) thereof.

[0040] The first base 41 may be composed of a connected body in which an approximately circular cylinder, an approximately elliptical cylinder, an approximately n-sided prism (regular n-sided prism), an approximately truncated cone, an approximately n-sided frustum (regular n-sided frustum), or any combination thereof is connected so as to be stacked coaxially.

[0041] 2, the second base 42 is formed in a shape in which a large-diameter cylindrical portion 421, a small-diameter cylindrical portion 422, a truncated cone portion 423, and a cylindrical portion 424 are coaxially connected from the proximal end to the distal end. The large-diameter cylindrical portion 421 is formed in a substantially cylindrical shape with a diameter φ21 (e.g., φ21 = 20 to 40 [mm]) and a length L21 (e.g., L21 = 10 to 40 [mm]). The small-diameter cylindrical portion 422 is formed in a substantially cylindrical shape with a diameter φ22 (e.g., φ22 = 15 to 35 [mm]) that is smaller than the large-diameter cylindrical portion 421, and a length L22 (e.g., L22 = 20 to 60 [mm]). The truncated cone portion 423 is formed in a substantially truncated cone shape with the distal end surface and the lower bottom surface of the small-diameter cylindrical portion 422 in common. The cylindrical portion 424 is formed in a generally cylindrical shape with a diameter φ24 (for example, φ24 = 10 to 30 mm) and a length L24 (for example, L24 = 10 to 30 mm) that shares one end surface with the lower bottom surface of the truncated cone portion 423.

[0042] The second base 42 may be composed of a connected body in which an approximately circular cylinder, an approximately elliptical cylinder, an approximately n-sided prism (regular n-sided prism), an approximately truncated cone, an approximately n-sided frustum (regular n-sided frustum), or any combination thereof is connected so as to be stacked coaxially.

[0043] 3, the second base 42 or the large-diameter cylindrical portion 421 has a male thread portion 420 formed therein extending in the axial direction from one end (proximal end) thereof. The male thread portion 420 of the second base 42 is inserted into and threadedly engaged with the female thread portion 410 of the first base 41, thereby removably attaching the first base 41 to the second base 42. The first base 41 may also be removably attached to the second base 42 by inserting and threading the male thread portion of the first base 41 into the female thread portion of the second base 42. Alternatively, the first base 41 may be removably attached to the second base 42 by a mechanical connecting mechanism such as a screw and / or a clamp.

[0044] 2, the rod portion 44 is formed in a generally cylindrical shape with a diameter φ4 (for example, φ4 = 8 to 25 mm) smaller than the cylindrical portion 424 of the second base portion 42, and a length L4 (for example, L4 = 40 to 200 mm). The ratio of the diameter φ4 to the length L4 of the rod portion 44 (φ4 / L4) is, for example, within the range of 0.02 to 0.10.

[0045] The rod portion 44 may be configured as a connected body in which an approximately circular cylinder, an approximately elliptical cylinder, an approximately n-sided prism (regular n-sided prism), an approximately truncated cone, an approximately n-sided frustum (regular n-sided frustum), or any combination thereof is connected so as to be stacked coaxially.

[0046] The length L4 of the rod portion 44 and the radius r of the circumscribed circle in its cross section (e.g., 2r = φ4) preferably have the relationship 20r≦L4≦100r. When the length L4 of the rod portion 44 is 20r or more, the rod portion 44 is more likely to bend overall when subjected to an axial force. When the length L4 of the rod portion 44 is 100r or less, excessive overall bending of the rod portion 44 when subjected to an axial force can be avoided.

[0047] The tip of the rod portion 44 (or the second rod portion 442) that is pressed against the workpiece W1 may be provided with a plurality of protrusions.

[0048] As shown in FIGS. 2 and 4 , the adjustment member 400 is formed in a generally perforated disk shape with a diameter φ0 (e.g., φ0 = 12 to 30 mm) that is smaller than the first base portion 41 and smaller than the large-diameter cylindrical portion 421 of the second base portion 42, and a thickness or length L0 (e.g., L0 = 9 to 30 mm). The ratio of the length L0 to the diameter φ0 of the adjustment member 400 (L0 / φ0) is, for example, within a range of 0.30 to 2.5. The male thread portion 420 of the second base portion 42 is passed through the through-hole of the adjustment member 400, and the female thread portion 410 of the first base portion 41 is screwed into the male thread portion 420 of the second base portion 42. As a result, the adjustment member 400 is removably attached to the base formed by the first base portion 41 and the second base portion 42 so as to be sandwiched between the first base portion 41 and the second base portion 42.

[0049] The shape of the outer contour of the cross section of the adjustment member 400 may be a substantially circular shape, or may be a shape having rotational symmetry around the central axis, such as a substantially elliptical shape or a substantially oval shape (see FIG. 5), or a substantially regular n-shape (n=3, 4, 5, ...) (see FIG. 6). The outer contour or circumscribing circle of the cross section of the adjustment member 400 may be entirely contained inside the outer contour or circumscribing circle of the cross section of the first base portion 41 and / or the second base portion 42 (maximum diameter portion) (see FIG. 4), or may partially extend outside the outer contour or circumscribing circle of the cross section of the first base portion 41 and / or the second base portion 42 (maximum diameter portion) (see FIGS. 5 and 6).

[0050] 2 and 4, the base portion formed by the first base portion 41 and the second base portion 42 is locally reduced in diameter over the entire circumference at the adjustment member 400 (adjustment portion). The ratio (φ0 / φ1) of the diameter φ0 of the adjustment member 400 to the diameter φ1 of the first base portion 41 is within a range of 0.30 to 0.75, for example. The ratio (φ0 / φ21) of the diameter φ0 of the adjustment member 400 to the diameter φ21 (maximum diameter) of the large-diameter cylindrical portion 421 of the second base portion 42 is within a range of 0.30 to 0.75, for example.

[0051] As shown in FIG. 7, the adjustment member 400 may be formed in a generally perforated disk shape with a diameter φ0 (e.g., φ0 = 30 to 60 mm) that is larger than the first base portion 41 and larger than the large-diameter cylindrical portion 421 of the second base portion 42, and a thickness or length L0 (e.g., L0 = 9 to 30 mm). The ratio of the length L0 to the diameter φ0 of the adjustment member 400 (L0 / φ0) is, for example, within the range of 0.15 to 1.0. The shape of the outer contour of the cross section of the adjustment member 400 may be a generally circular shape, a generally elliptical shape, a generally oval shape (see FIG. 5), or a generally regular n-shape (n = 3, 4, 5, ...) (see FIG. 6), or other shape that has rotational symmetry around the central axis. The adjustment member 400 may be composed of an approximately cylindrical body, an approximately elliptical cylinder, an approximately n-sided cylinder (regular n-sided cylinder), an approximately truncated conical cylinder or an approximately n-sided truncated pyramidal cylinder (regular n-sided truncated pyramidal cylinder), or a connected body in which any combination of these cylinders are connected so as to be stacked coaxially.

[0052] The adjustment member 400 may be formed in a generally perforated disk shape with a diameter φ0 (e.g., φ0 = 20 to 40 mm) that is the same diameter as the first base portion 41 and the same diameter as the large-diameter cylindrical portion 421 of the second base portion 42, and a thickness or length L0 (e.g., L0 = 9 to 30 mm).

[0053] The first base portion 41, the second base portion 42, and the rod portion 44 are formed of the same or different types of cemented carbide alloys. Examples of cemented carbide alloys that can be used include WC-Co alloys, WC-TiC-Co alloys, WC-TaC-Co alloys, WC-TiC-TaC-Co alloys, WC-Ni alloys, and WC-Ni-Cr alloys. The adjustment member 400 is made of stainless steel. Examples of stainless steel that can be used include martensitic stainless steel, ferritic stainless steel, austenitic stainless steel, and precipitation-hardened stainless steel.

[0054] The Young's modulus E of the cemented carbide constituting the base portions (first base portion 41 and second base portion 42) of horn tip 40 is, for example, within the range of 450 to 650 GPa. The Young's modulus E0 of the stainless steel constituting adjustment member 400 is, for example, within the range of 180 to 220 GPa. The ratio (E0 / E) of the Young's modulus E of the cemented carbide constituting the base portions of horn tip 40 to the Young's modulus E of the stainless steel constituting adjustment member 400 is, for example, within the range of 0.28 to 0.49.

[0055] The adjustment member 400 may be composed of a plurality of members connected together in an annular shape by a mechanical connection mechanism such as a screw or a clamp. In this case, the plurality of members are connected together in an annular shape so as to fasten the intermediate portion of the base, thereby allowing the adjustment member 400 to be detachably attached to the base. The intermediate member of the base may be formed to have a locally reduced diameter.

[0056] (Ultrasonic bonding method) The procedure of an ultrasonic bonding method according to one embodiment of the present invention using the ultrasonic bonding apparatus 1 will be described with reference to the flowchart in Fig. 2. As shown in Fig. 2, a first workpiece W1 and a second workpiece W2 are placed on the anvil 18 in a stacked state from top to bottom.

[0057] The ultrasonic complex vibration device 10 and the horn tip 40 are moved in the radial direction by the translational drive device 222 so as to approach the first workpiece W1 and the second workpiece W2 (FIG. 8 / STEP 112).

[0058] Furthermore, it is determined whether the pressure P that horn tip 40 receives from first workpiece W1 (and second workpiece W2) is equal to or greater than first specified pressure P1 (FIG. 8 / STEP 114). The pressure P that horn tip 40 receives from first workpiece W1 is measured based on the output signal of a pressure sensor that constitutes state sensor 224. When the tip of horn tip 40 is separated from workpiece W1, P=0. For example, as shown in FIG. 3, when the tip of horn tip 40 comes into contact with first workpiece W1 that is inserted into through-hole W20 of second workpiece W2, a reaction force is received, so that P>0.

[0059] If the determination result is negative (FIG. 8 / STEP 114...NO), the translational drive device 222 moves the ultrasonic complex vibration device 10 and the horn tip 40 in the radial direction so as to approach the first workpiece W1 inserted into the through-hole W20 of the second workpiece W2 (FIG. 2 / connector X1 →STEP 112). As a result, the position of the horn tip 40, and therefore the static pressure applied from the horn tip 40 to the first workpiece W1 and the second workpiece W2, is adjusted to be within a specified static pressure range (e.g., 200 N to 800 N).

[0060] If the determination result is affirmative (FIG. 8 / STEP 114...YES), ultrasonic vibrations are generated in the ultrasonic vibrator (FIG. 8 / STEP 116). Specifically, in response to power being supplied to the high-frequency power supply device 221 from a commercial power source (not shown) via a slip ring or the like, the high-frequency power supply device 221 applies a high-frequency AC voltage to the piezoelectric body 112 of the first ultrasonic vibrator 110. This causes the first ultrasonic vibrator 110 to vibrate in its axial direction at, for example, approximately 20 KHz, generating ultrasonic vibrations. The ultrasonic vibrations are transmitted from the first ultrasonic vibrator 110 to the intermediate ultrasonic vibrator 100 in its axial direction, and the amplitude of the ultrasonic vibrations is amplified. Furthermore, the ultrasonic vibrations with amplified amplitude are transmitted from the intermediate ultrasonic vibrator 100 to the second ultrasonic vibrator 120 in its axial direction.

[0061] In this way, a portion of the longitudinal vibration component (axial component of the second ultrasonic vibrator 120) of the ultrasonic vibration transmitted to the second ultrasonic vibrator 120 is converted into a torsional vibration component by the plurality of slits 124 formed on the outer surface of the second ultrasonic vibrator 120. Then, a composite vibration generated by combining the longitudinal vibration component and the torsional vibration component is transmitted to the horn tip 40 fixed to the tip of the second ultrasonic vibrator 120.

[0062] In response, the horn tip 40 displaces or vibrates in a circular or elliptical orbit on a plane perpendicular to the contact direction of the first workpiece W1. As a result, the amplitude and ultrasonic vibration power of the horn tip 40 gradually increase from the vibration start time t=t0. During this process, impurities are removed from the contact surface between the first workpiece W1 and the second workpiece W2, further promoting plastic deformation of the contact surface between the first workpiece W1 and the second workpiece W2. After the rate of increase in the amplitude and ultrasonic vibration power of the horn tip 40 significantly decreases at time t=t1, the amplitude and ultrasonic vibration power of the horn tip 40 gradually increase. This is due to the removal of oxide coatings and other metals constituting the joining surfaces of the first workpiece W1 and the second workpiece W2, revealing clean, activated metal atoms at the joining surfaces. The temperature rise due to frictional heat activates the atomic movement, generating mutual attraction between the atoms.

[0063] At this time, the composite vibration is applied to the first workpiece W1 and the second workpiece W2 while adjusting the amount of pressing of the first workpiece W1 and the second workpiece W2 by the horn tip 40 and / or the static pressure applied to the first workpiece W1 and the second workpiece W2. As a result, as shown in Fig. 4, the outer surface and the peripheral edge of the lower surface of the first workpiece W1 can be solid-state welded to the stepped portion W22 of the second workpiece W2 over the entire circumference.

[0064] 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 equal to or less than the reference amplitude A0 (FIG. 8 / STEP 118). An amplitude sensor constituting the state sensor 224 optically measures the amplitude A at a specified location (e.g., a location where the amplitude is relatively large) of the horn tip 40. Instead of this determination process, 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 the time when the amplitude A started to decrease as a reference. For example, the reference amplitude A0, such as one of multiple joining modes for which the reference amplitude A0 is determined, may be directly or indirectly specified via a touch panel display constituting the operation device 20.

[0065] If the determination result is negative (FIG. 8 / STEP 118...NO), ultrasonic vibrations are continuously generated in the ultrasonic vibrator (FIG. 2 / connector X2 →STEP 116). On the other hand, if the determination result is positive (FIG. 8 / STEP 118...YES), the translational drive device 222 moves the ultrasonic complex vibration device 10 and the horn tip 40 away from the first workpiece W1 and the second workpiece W2 (FIG. 8 / STEP 122).

[0066] Furthermore, it is determined whether the pressure P that the horn tip 40 receives from the first workpiece W1 (and the second workpiece W2) has become equal to or less than a second designated pressure P2 (FIG. 8 / STEP 124). The second designated pressure P2 is set to a value smaller than the first designated pressure P1, for example, 0 or a very small value.

[0067] If the determination result is negative (FIG. 8 / STEP 124...NO), the translational drive device 222 moves the ultrasonic complex vibration device 10 and the horn tip 40 away from the first workpiece W1 and the second workpiece W2 (FIG. 2 / connector X4 →STEP 122). This adjusts the radial position of the horn tip 40, and therefore the static pressure applied from the horn tip 40 to the first workpiece W1 and the second workpiece W2, so as to decrease.

[0068] If the determination result is positive (FIG. 8 / STEP 124...YES), the generation of ultrasonic vibrations in the ultrasonic vibrator is stopped (FIG. 8 / STEP 126). For example, after the amplitude of the horn tip 40 changes from increasing to decreasing and becomes equal to or less than the reference amplitude A0 at time t=t2, the ultrasonic power of the horn tip 40 is controlled to become 0 with a slight response delay. This stops the series of processes.

[0069] (effect) With the ultrasonic bonding device configured as described above, while the tip of the horn tip 40 (ultrasonic bonding tip) is pressed against the first workpiece W1, ultrasonic complex vibrations are applied to the first workpiece W1 and the second workpiece W2 in a direction (horizontal direction) perpendicular to the pressing direction. This deflects the adjustment member 400, which is attached to the base so as to be sandwiched between the first base portion 41 and the second base portion 42. This is because the ratio (E0 / E) of the Young's modulus E of the material constituting the adjustment member to the Young's modulus E of the material constituting the first base portion 41 and the second base portion 42 of the horn tip 40, and thus the base, is in the range of 0.28 to 0.49. This allows the tip of the rod portion 44 connected to the base to ultrasonically vibrate not only horizontally but also vertically (three-dimensionally).

[0070] Due to the vertical ultrasonic vibrations, in the early stages of joining the multiple workpieces W1 and W2, the pressing force of the tip of the rod portion 44 against the workpieces W1 and W2 intermittently increases, thereby suppressing misalignment of the multiple workpieces W1 and W2. In the middle and final stages of joining the multiple workpieces W1 and W2, part of the ultrasonic vibration energy applied to the multiple workpieces W1 and W2 can be converted into vertical ultrasonic vibrations of the rod portion 44, thereby preventing excessive horizontal ultrasonic vibrations from being applied to the multiple workpieces W1 and W2. As a result, the quality of joining the workpieces W1 and W2 is improved.

[0071] (Example) A substantially cylindrical first base portion 41 (diameter 15 mm, length 18 mm) made of stainless steel SUS304 (Young's modulus 193 GPa), a substantially circular rod portion 42 (diameter 15 mm, length 32.2 mm) made of stainless steel SUS304 (Young's modulus 193 GPa), and a substantially circular second base portion 42 (diameter 3.5 mm, length 90.75 mm) made of superalloy MC20 (Young's modulus 620 GPa), Four types of adjustment members 400 were prepared, each of which was approximately cylindrical (length L0 = 7 mm) and had different outer diameters of φ13 mm (Example 1) made of stainless steel CR20 (Young's modulus 200 GPa), and φ15 mm, 23 mm, and 28 mm (Examples 2 to 4) made of pure titanium (Young's modulus 106 GPa), along with horn tips 40 for Examples 1 to 4, respectively.

[0072] Then, the amplitudes in the x- and y-directions (two directions perpendicular to the horizontal direction) and z-direction (vertical direction) were evaluated by simulation for (1) the unloaded state and (2) the loaded state. In (1) the unloaded state, the ultrasonic complex vibration device 10 was driven at 10% of its maximum driving power (which varies depending on the specifications of the ultrasonic complex vibration device 10), and the horn tip 40 was in an unloaded state (not in contact with the workpiece). In (2) the unloaded state, the ultrasonic complex vibration device 10 was driven at 20% of its maximum driving power, and a load of 150 N was applied to the horn tip 40 in the axial direction. Table 1 summarizes the evaluation results.

[0073] [Table 1]

[0074] As is clear from Table 1, it was confirmed that in each of the horn tips 40 of Examples 1 to 4 according to one embodiment of the present invention, amplitude in the z direction occurred both in the unloaded state and in the loaded state.

[0075] (Another embodiment of the present invention) In the above embodiment, the amplitude A of the horn tip 40 was measured as a specified parameter that changes depending on the progress of joining one workpiece W1 and the other workpiece W2, but in other embodiments, the axial displacement amount, displacement velocity and / or displacement acceleration of the ultrasonic vibrator (e.g., the second ultrasonic vibrator 12) may be measured as a specified parameter. [Explanation of symbols]

[0076] 10. Ultrasonic complex vibration device 100...Intermediate ultrasonic vibrator 102...Intermediate flange 110...First ultrasonic vibrator 112. Piezoelectric material 120...Second ultrasonic vibrator 122...Frequency adjustment element 124. Slit 126‥Tip 128 holes 18. Anvil 20‥Operation device 22. Control device 221‥High frequency power supply equipment 222...Translation drive device 224...Status sensor 40. Horn tip (tip for ultrasonic bonding) 41‥1st base 42‥Second base 44. Rod section 400...Adjustment member (adjustment part) W1: First work W2: Second work.

Claims

1. a base portion; a rod portion connected to the base portion; and an adjustment member removably attached to the base portion at an intermediate portion of the base portion in an axial direction thereof; the Young's modulus E of the material constituting the base is in the range of 450 to 650 GPa; The Young's modulus E0 of the material constituting the adjustment member is in the range of 180 to 220 GPa, The ratio (E0 / E) of the Young's modulus E0 of the material constituting the adjusting member to the Young's modulus E of the material constituting the base portion is in the range of 0.28 to 0.

49. Ultrasonic bonding tip.

2. 2. The ultrasonic bonding tip according to claim 1, the base portion is composed of a first base portion to which the rod portion is connected and a second base portion provided so as to be displaceable or detachable relative to the first base portion, The adjustment member is attached to the base portion in a state where it is sandwiched between the first base portion and the second base portion. Ultrasonic bonding tip.

3. 3. The ultrasonic bonding tip according to claim 2, When the adjustment member is attached to the base, the adjustment member has at least one of a portion that protrudes from the base and a portion that is recessed in a direction perpendicular to the axial direction of the base. Ultrasonic bonding tip.

4. 2. The ultrasonic bonding tip according to claim 1, The base and the adjustment member are each formed to have a columnar portion that has rotational symmetry around a central axis. Ultrasonic bonding tip.

5. an ultrasonic vibrator that induces a composite vibration by combining longitudinal vibration and torsional vibration; an ultrasonic bonding tip; a control device for controlling the complex vibration of the ultrasonic vibrator, The ultrasonic bonding tip comprises: a base portion; a rod portion connected to the base portion; and an adjustment member removably attached to the base portion at an intermediate portion of the base portion in an axial direction thereof; the Young's modulus E of the material constituting the base is in the range of 450 to 650 GPa; The Young's modulus E0 of the material constituting the adjustment member is in the range of 180 to 220 GPa, The ratio (E0 / E) of the Young's modulus E0 of the material constituting the adjusting member to the Young's modulus E of the material constituting the base portion is in the range of 0.28 to 0.

49. Ultrasonic bonding equipment.

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