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: A horn chip 40 includes: a base portion 41 in which a first male screw 411 close to a rear end portion and a second male screw 412 close to a distal end portion, which are screwed to a first female screw 128 formed in an ultrasonic vibrating body, are formed on an outer surface; a rod portion 42 extending from the distal end portion of the base portion 41; and a cylindrical adjustment member 44 in which a second female screw 440 is formed on an inner surface. When the second male screw 412 of the base portion 41 is screwed into the second female screw 440 of the adjustment member 44 in a state where the first male screw 411 is screwed into the first female screw 128 of the ultrasonic vibrating body, the base portion 41 is fastened to the ultrasonic vibrating body. The base portion 41 is made of a super steel alloy. The adjustment member 44 is made of stainless steel.SELECTED DRAWING: Figure 2A

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. 7082434 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 having a first male screw near the rear end portion and a second male screw near the front end portion formed on an outer surface thereof, the first male screw being screwed into a first female screw formed on the ultrasonic vibrator; a rod portion extending from a tip end of the base portion; a cylindrical adjustment member having a second female screw formed on an inner surface thereof for fastening the base to the ultrasonic vibrator by being threaded onto the second male screw of the base in a state in which the first male screw is threaded onto the first female screw of the ultrasonic vibrator, The base is made of a super steel alloy, The adjustment member is made of stainless steel.

[0007] In an ultrasonic bonding tip (hereinafter sometimes simply referred to as "tip") having this configuration, the Young's modulus E (e.g., within the range of 450 to 650 GPa) of the super steel alloy constituting the base is higher than the Young's modulus E0 (e.g., within the range of 180 to 220 GPa) of the stainless steel constituting the adjustment member. 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 extending from the tip of 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. Additionally or alternatively, an adjustment member can be selectively attached to each of multiple bases with different specifications. This allows the ultrasonic complex vibrations in the two directions (vertical and horizontal) applied from the tip to multiple workpieces to be adjusted. By selecting an appropriate adjustment member according to 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 joining the multiple workpieces can be improved. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating the configuration of an ultrasonic bonding device according to an embodiment of the present invention. [Figure 2A] FIG. 1 is an exploded explanatory view of an ultrasonic bonding tip according to an embodiment of the present invention. [Figure 2B] 1 is an explanatory diagram illustrating assembly of an ultrasonic bonding tip according to one embodiment of the present invention. [Figure 3A] FIG. 10 is an exploded explanatory view of an ultrasonic bonding tip according to another embodiment of the present invention. [Figure 3B] 10A and 10B are explanatory diagrams illustrating the assembly of an ultrasonic bonding tip according to another embodiment of the present invention. [Figure 4] 3 is a flowchart showing the function of the ultrasonic bonding device. DETAILED DESCRIPTION OF THE INVENTION

[0011] (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.

[0012] 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."

[0013] 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.

[0014] 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.

[0015] As shown in FIG. 1, the first ultrasonic vibrator 110 is provided with a piezoelectric body 112 whose piezoelectric polarization direction is in the axial direction (parallel to the first axis).

[0016] 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).

[0017] 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.

[0018] 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.

[0019] As shown in FIG. 1 , the second ultrasonic vibrating body 12 is provided with a tip portion 126 that is approximately regular octagonal in shape with rounded corners and 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 (first female thread) is provided on the inner surface of the hole 128. The entire tip portion 126 is made of stainless steel, or a portion of the tip portion 126 surrounding the hole 128 is locally made of stainless steel.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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).

[0026] 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.

[0027] 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.

[0028] A horn tip 40 according to one embodiment of the present invention, shown in FIGS. 2A and 2B, includes a base 41, a rod 42, and an adjustment member 44. As shown in FIG. 2A, the base 41 is formed in a generally cylindrical shape (or a shape resembling a coaxial connection of a generally cylindrical body and a generally cylindrical body of the same diameter, or a generally cylindrical shape). For example, the base 41 is formed in a generally cylindrical shape with a diameter φ1 (e.g., φ1 = 15 to 25 mm) and a length L1 (e.g., L1 = 15 to 25 mm). A male thread 410 is formed on the outer surface of the base 41. As shown in FIG. 2A, the male thread 410 is composed of a first male thread 411 near the rear end and a second male thread 412 near the front end. The specifications of the first male thread 411 and the second male thread 412 (the respective reference dimensions of the outer diameter, root diameter, and effective diameter, as well as the pitch) may be the same or different from each other. The first male thread 411 and the second male thread 412 may be formed continuously in the axial direction of the base portion 41, or may be separated.

[0029] 2A and 2B, rod portion 42 extends coaxially and continuously from the tip end of base portion 41, and is formed in a generally cylindrical shape having a smaller diameter than base portion 41 and being longer in the axial direction than base portion 41. For example, rod portion 42 is formed in a generally cylindrical shape with a diameter φ2 (e.g., φ2 = 5 to 20 mm) and a length L2 (e.g., L2 = 50 to 150 mm). Rod portion 42 may be formed of a generally cylindrical body, a generally elliptical cylinder, a generally n-sided prism (regular n-sided prism), a generally truncated cone, or a generally n-sided truncated pyramid (regular n-sided truncated pyramid), or any combination thereof connected and stacked coaxially.

[0030] The length L2 of the rod portion 42 and the area S of the circumscribed circle in its cross section (for example, π(R4) 2 ) between, for example, 5S 1 / 2 ≦L≦50S 1 / 2 , 10S 1 / 2 ≦L≦40S 1 / 2 , or 15S 1 / 2 ≦L≦25S 1 / 2The tip of the rod portion 42 abuts against the uppermost workpiece W1 of the first workpiece W1 and the second workpiece W2. The tip of the rod portion 42 may be provided with, for example, one or more convex portions and / or one or more concave portions.

[0031] The base 41 and the rod portion 42 are integrally formed from a cemented carbide. Alternatively, the base 41 and the rod portion 42 may be formed separately, and the high end of the rod portion 42 may be inserted into a hole in the base 41 or a hole near the tip, and then integrated by shrink fitting, welding, or the like. In this case, the base 41 and the rod portion 42 may be made of the same cemented carbide, or may be made of different cemented carbide alloys. Examples of cemented carbide alloys that can be used include WC-Co based alloys, WC-TiC-Co based alloys, WC-TaC-Co based alloys, WC-TiC-TaC-Co based alloys, WC-Ni based alloys, and WC-Ni-Cr based alloys.

[0032] The adjustment member 44 is formed in a generally cylindrical shape, and a second internal thread 440 is formed on its inner surface. The adjustment member 44 may be formed in a generally cylindrical shape with a diameter φ0 (e.g., φ0 = 20 to 30 mm) and a length L0 (e.g., L0 = 20 to 30 mm). The ratio of the length L0 to the diameter φ0 of the adjustment member 44 (L0 / φ0) is, for example, within the range of 0.5 to 2.0. The adjustment member 44 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. The shape of the outer contour of the cross section of the adjustment member 44 may be a generally circular shape, a generally elliptical shape, a generally oval shape, or a generally regular n-shape (n = 3, 4, 5, etc.) that has rotational symmetry about a central axis. The adjustment member 44 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.

[0033] As shown in Fig. 2B, a first male screw 411 provided on the base 41 of the horn tip 40 is threaded into a first female screw provided in the hole 128 of the tip 126 of the second ultrasonic vibrator 12. Furthermore, as shown in Fig. 2B, a second female screw 440 of the adjustment member 44 is threaded into a second male screw 412 provided on the base 41 of the horn tip 40. Then, by threading the end of the adjustment member 44 until it abuts against the tip 126, the horn tip 40 or the base 41 is tightened (removably attached) to the tip 126 or the ultrasonic vibrator by the adjustment member 44.

[0034] This allows the base portion 41 to be attached to the tip portion 126 in a state where the azimuth angle or rotation angle around the central axis of the rod portion 42 is arbitrarily changed. This is meaningful when the rod portion 42 or its tip portion has an anisotropic shape and / or is normal with respect to the central axis.

[0035] By preparing multiple bases 41 and / or multiple adjustment members 44 of various shapes and sizes, the configuration of horn tip 40 can be changed depending on the type of metal to be joined, etc. For example, in horn tip 40 as another embodiment of the present invention shown in Figures 3A and 3B, adjustment member 44 is integrally formed from a substantially cylindrical small-diameter portion 441 and a substantially cylindrical large-diameter portion 442 located at an intermediate portion of small-diameter portion 441 and having a larger diameter than small-diameter portion 441. The other configuration of horn tip 40 of the other embodiment shown in Figures 3A and 3B is substantially the same as the configuration of horn tip 40 of the embodiment shown in Figures 2A and 2B, so the same reference numerals are used and detailed description will be omitted.

[0036] (Ultrasonic bonding method) The procedure of an ultrasonic bonding method according to one embodiment of the present invention using an ultrasonic bonding device will be described with reference to the flowchart in Fig. 2. As shown in Fig. 1, a first workpiece W1 and a second workpiece W2 are placed on an anvil 18 in a stacked state from top to bottom.

[0037] 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. 4 / STEP 112).

[0038] 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. 4 / 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.

[0039] If the determination result is negative (FIG. 4 / 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).

[0040] If the determination result is affirmative (FIG. 4 / STEP 114...YES), ultrasonic vibrations are generated in the ultrasonic vibrator (FIG. 4 / 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.

[0041] 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.

[0042] In response, the horn tip 40 displaces or vibrates in a circular or elliptical orbit in a plane (xy plane) perpendicular to the contact direction (z 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 on the contact surface between the first workpiece W1 and the second workpiece W2 are removed, 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 because the oxide coatings and other metals constituting the joining surfaces of the first workpiece W1 and the second workpiece W2 are removed, revealing clean, activated metal atoms on the joining surfaces. The temperature rise due to frictional heat activates the atomic movement, generating mutual attraction between the atoms.

[0043] 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.

[0044] 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. 4 / 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.

[0045] If the determination result is negative (FIG. 4 / STEP 118...NO), ultrasonic vibrations are continuously generated in the ultrasonic vibrator (FIG. 4 / connector X2 →STEP 116). On the other hand, if the determination result is positive (FIG. 4 / 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. 4 / STEP 122).

[0046] 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. 4 / 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.

[0047] If the determination result is negative (FIG. 4 / 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. 4 / connector X4 →STEP 122). This reduces the radial position of the horn tip 40, and therefore reduces the static pressure applied from the horn tip 40 to the first workpiece W1 and the second workpiece W2.

[0048] If the determination result is affirmative (FIG. 4 / STEP 124...YES), the generation of ultrasonic vibrations in the ultrasonic vibrator is stopped (FIG. 4 / STEP 126). For example, after the time t=t2 when the amplitude of the horn tip 40 changes from increasing to decreasing and becomes equal to or less than the reference amplitude A0, the ultrasonic power of the horn tip 40 is controlled to become 0 with a slight response delay. This stops the series of processes.

[0049] (effect) In the ultrasonic bonding device having the above configuration, the Young's modulus E (e.g., in the range of 450 to 650 GPa) of the super steel alloy constituting the base 41 is higher than the Young's modulus E0 (e.g., in the range of 180 to 220 GPa) of the stainless steel constituting the adjustment member 44. As a result, when the tip of the rod portion 42 of the horn tip 40 is pressed against the first workpiece W1 and ultrasonic complex vibrations are applied to the first workpiece W1 and the second workpiece W2 in a direction (lateral direction) perpendicular to the pressing direction (vertical direction), the adjustment member 44 attached to the base 41 can be deflected. As a result, the tip of the rod portion 42 extending from the tip of the base 41 can be ultrasonically vibrated not only in the lateral direction but also in the longitudinal direction (three-dimensionally).

[0050] 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.

[0051] (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), Three types of adjustment members 400 were prepared, each made of stainless steel CR20 (Young's modulus 200 GPa), approximately cylindrical (length L0 = 7 mm) with different outer diameters of φ15 mm, 23 mm, and 28 mm, and horn tips 40 of Examples 1 to 3.

[0052] 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.

[0053] [Table 1]

[0054] As is clear from Table 1, it was confirmed that in all of the horn tips 40 of Examples 1 to 3 according to one embodiment of the present invention, amplitude in the z direction occurred both in the unloaded state and in the loaded state.

[0055] (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]

[0056] 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...hole (first female thread) 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‥Base 411...First male screw 412...Second male screw 42...Rod section 44. Adjustment member 440...Second female screw 441‥Small diameter part 442...Large diameter section W1: First work W2: Second work.

Claims

1. a base portion having a first male screw near the rear end portion and a second male screw near the front end portion formed on an outer surface thereof, the first male screw being screwed into a first female screw formed on the ultrasonic vibrator; a rod portion extending from a tip end of the base portion; a cylindrical adjustment member having a second female screw formed on an inner surface thereof for fastening the base to the ultrasonic vibrator by being threaded onto the second male screw of the base in a state in which the first male screw is threaded onto the first female screw of the ultrasonic vibrator, The base is made of a super steel alloy, The adjustment member is made of stainless steel. Ultrasonic bonding tip.

2. 2. The ultrasonic bonding tip according to claim 1, The plurality of adjustment members, each having a different shape, size, or Young's modulus, are selectively attached to the base. Ultrasonic bonding tip.

3. 3. The ultrasonic bonding tip according to claim 1, The adjustment member is selectively attached to each of the plurality of bases that differ in at least one of shape, size, and Young's modulus. Ultrasonic bonding tip.

4. an ultrasonic vibrator that induces a composite vibration by combining longitudinal vibration and torsional vibration; An ultrasonic bonding device comprising: an ultrasonic bonding tip; The ultrasonic bonding tip comprises: a base portion having a first male screw near the rear end portion and a second male screw near the front end portion formed on an outer surface thereof, the first male screw being screwed into a first female screw formed on the ultrasonic vibrator; a rod portion extending from a tip end of the base portion; a cylindrical adjustment member having a second female screw formed on an inner surface thereof for fastening the base to the ultrasonic vibrator by being threaded onto the second male screw of the base in a state in which the first male screw is threaded onto the first female screw of the ultrasonic vibrator, The base is made of a super steel alloy, The adjustment member is made of stainless steel, At least the portion of the ultrasonic vibrator where the first male screw is formed is made of stainless steel. Ultrasonic bonding equipment.

Images