ULTRASONIC TOOL AND ULTRASONIC CONNECTION DEVICE HEREIN

Abstract

An ultrasonic tool comprising a first end face and a second end face, which is opposite the first end face, as well as a tool cover surface connecting the first end face and the second end face, wherein the ultrasonic tool is elongated in a longitudinal direction of the tool, wherein at least the first end face is formed as a connecting contact surface, which is arranged for pressing the ultrasonic tool against a connecting component, and wherein the ultrasonic tool comprises an end region comprising the connecting contact surface, which extends from the connecting contact surface in the longitudinal direction of the tool over 15 mm, but at most extends one third of the length of the ultrasonic tool in the direction of the opposite end face, and wherein in the end region, a first partial surface of the tool cover surface is formed as a surface-structured absorption surface.

Claims

1. An ultrasonic tool comprising: a first end face; a second end face arranged opposite to the first end face; a tool cover surface connecting the first end face and the second end face, wherein the ultrasonic tool is elongated in a longitudinal direction of the tool, wherein at least the first end face is formed as a connecting contact surface, which is arranged for pressing the ultrasonic tool against a connecting component, wherein the ultrasonic tool comprises an end region comprising the connecting contact surface, which extends from the connecting contact surface in the longitudinal direction of the tool over 15 mm, but at most extends one third of the length of the ultrasonic tool in the direction of the opposite end face, and wherein, in the end region, a first partial surface of the tool cover surface is formed as a surface-structured absorption surface.

2. The ultrasonic tool according to claim 1, wherein an absorption coefficient of the absorption surface is greater than an absorption coefficient of a second partial area of the tool cover surface adjacent to the absorption surface and/or as an absorption coefficient of the tool cover surface outside the end region.

3. The ultrasonic tool according to claim 1, wherein the absorption surface comprises grooved surface structures and/or dot-shaped surface structures and/or wherein the absorption surface is regularly structured.

4. The ultrasonic tool according to claim 3, wherein the grooved surface structures are arranged parallel structured and/or cross-structured and/or that the grooved surface structures extend transversely to the longitudinal direction of the tool.

5. The ultrasonic tool according to claim 1, wherein the surface structure of the absorption surface is formed as a microstructure, wherein the roughness of the first partial surface forming the absorption surface is greater than the roughness of the second partial surface of the tool cover surface and/or wherein a depth of the microstructures established vertically to the tool cover surface is greater than 1 μm and preferably in the range of 10 μm to 350 μm.

6. The ultrasonic tool according to claim 1, wherein the absorption surface is macroscopically flat and/or that the absorption surface is oriented oblique to the longitudinal direction of the tool and/or wherein, like the first partial surface, the second partial surface is provided in the end region.

7. The ultrasonic tool according to claim 1, wherein the surface-structured absorption surface comprises a coating.

8. The ultrasonic tool according to claim 1, wherein the absorption surface is symmetrically oriented with respect to a median longitudinal surface of the tool, which receives the longitudinal direction of the tool and/or wherein the median longitudinal surface of the tool is formed as a symmetry surface of the ultrasonic tool and/or wherein the ultrasonic tool is symmetrically formed with respect to a transverse median surface which is oriented perpendicular to the longitudinal direction of the tool, and wherein the second end face is also formed as a connecting contact surface.

9. The ultrasonic tool according to claim 1, wherein a contact contour is provided on the at least one connecting contact surface and/or wherein, in the end region and with respect to a cross-section oriented perpendicular to the longitudinal direction of the tool, the ultrasonic tool, at least in sections, tapers towards the connecting contact surface.

10. The ultrasonic tool according to claim 1, wherein the surface-structured absorption surface is prepared by wire EDM and/or by die-sinking EDM and/or by electrochemical ablation and/or by engraving and/or by laser ablation and/or primary forming and/or wherein the ultrasonic tool is formed of a carbide or steel or a ceramic and preferably of a tungsten carbide-based carbide or boron nitride and/or particularly preferably comprises tungsten carbide in a cobalt matrix.

11. An ultrasonic connection device for ultrasonic welding and/or ultrasonic bonding, comprising: an ultrasonic tool according to claim 1, comprising at least one surface-structured absorption surface formed on the tool cover surface; an ultrasonic generator and a transducer, wherein the ultrasonic generator excites the transducer to vibrate, and the transducer interacts with the ultrasonic tool such that the ultrasonic tool is excitable to ultrasonic vibrations and preferably to ultrasonic bending vibrations; and a laser generator for providing a laser beam; wherein the laser beam is aligned with the end region of the ultrasonic tool such that it completely or at least partially, impinges on the absorption surface of the ultrasonic tool formed there.

12. The ultrasonic connection device according to claim 11, wherein the surface structure of the absorption surface is formed as a microstructure and that the depth of the microstructure is greater than a wavelength of the laser beam and is greater than the wavelength of the laser beam by a factor of 10 or more.

13. The ultrasonic connection device according to claim 11, wherein the wavelength of the laser beam is matched to the material of the ultrasonic tool and/or the texture of the surface structure and/or the coating in such a way that, for the absorption surface, an absorption coefficient of at least 0.81 and preferably of 0.86 or more and particularly preferably of at least 0.9 is provided.

14. The ultrasonic connection device according to claim 11, wherein the laser beam is aligned such that it impinges on the absorption surface in an oblique or non-perpendicular manner.

15. The ultrasonic connection device according to claim 11, wherein the absorption coefficient of the surface-structured absorption surface varies as a function of an angle of incidence of the laser beam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0033] FIG. 1 is a perspective representation of a first embodiment of an ultrasonic tool, which is elongated in the longitudinal direction of a tool comprising an end region at which a surface-structured absorption surface is formed,

[0034] FIG. 2 is an enlarged view of the end region of the ultrasonic tool according to FIG. 1 comprising the absorption surface,

[0035] FIG. 3 is the end region of the ultrasonic tool according to FIGS. 1 and 2, wherein a laser beam divergently impinges on the absorption surface,

[0036] FIG. 4 is a comparison between heating curves for the ultrasonic tool according to FIGS. 1 to 3 and a conventional ultrasonic tool without absorption surface,

[0037] FIG. 5 is the end region of the ultrasonic tool according to FIGS. 1 to 3 comprising a collimated laser beam,

[0038] FIG. 6 is the end region of the ultrasonic tool according to FIG. 2, wherein a laser beam convergently impinges on the absorption surface,

[0039] FIG. 7 is a perspective view of a second embodiment of the ultrasonic tool, which provides a contact contour for a connecting component on a connecting contact surface provided in the end region,

[0040] FIG. 8 is an enlarged view of the end region of the ultrasonic tool according to FIG. 7,

[0041] FIGS. 9A to 9D are an exemplary compilation of different types of surface structuring of the absorption surface,

[0042] FIG. 10 is a schematic diagram of a geometry of the surface structure,

[0043] FIG. 11 is various exemplary beam paths for the laser beam impinging on the surface structure,

[0044] FIGS. 12A to 12E are various exemplary types of surface structuring of the absorption surface in cross-section,

[0045] FIG. 13 is a perspective view of a third embodiment of an ultrasonic tool, which is symmetrically formed in respect of a cross-section plane which is oriented perpendicular to the longitudinal direction of the tool,

[0046] FIG. 14 is a side view of the ultrasonic tool according to FIG. 13,

[0047] FIG. 15 is a front view of the ultrasonic tool according to FIG. 13, and

[0048] FIG. 16 is the ultrasonic tool according to FIG. 13 comprising a laser beam divergently impinging on the absorption surface.

DETAILED DESCRIPTION

[0049] The ultrasonic tool 1 according to FIG. 1 provides a first end face 2 formed as a connecting contact surface, a second end face 3, which is opposite the first end face 2, and a tool cover surface 4 connecting the end faces 2, 3. The ultrasonic tool 1 is elongated in a longitudinal direction of the tool 5. It has a length L from the first end face 2 to the second end face 3, which is greater than 50 mm. With respect to the longitudinal direction of the tool 5, the lower 15 mm of the ultrasonic tool 1 comprising the connecting contact surface 2 form an end region 6 of the ultrasonic tool 1. In the end region 6, the ultrasonic tool 1 tapers in a wedge-shaped manner in respect of a cross-section oriented vertically to the longitudinal direction of the tool 5 in the direction of the connecting contact surface 2. The ultrasonic tool 1 is symmetrically designed in relation to a longitudinal center plane of the tool 13 which receives the longitudinal direction of the tool 5.

[0050] The connecting contact surface 2 is substantially perpendicular to the longitudinal direction of the tool 5. The connecting contact surface 2 is used to support or press a connecting component against the ultrasonic tool 1.

[0051] In the end region 6, a microstructured absorption surface 7 is provided on the tool cover surface 4 at a distance from the connecting contact surface 2. The absorption surface 7, which is shown enlarged in FIG. 2, is formed by grooved microstructures, which in the present case are regularly structured, parallel to each other in two groups and arranged intersecting at an angle of 45°. The microstructures have a depth T of about 10 μm and a width B or a distance that is about half the depth T.

[0052] Due to the microstructuring of the tool cover surface 4, the absorption coefficient of the absorption surface is 7 greater than the absorption coefficient of the tool cover surface 4 outside the absorption surface 7. Typically, the absorption coefficient of the absorption surface 7 is in the range of 0.9 or more.

[0053] FIG. 3 shows a divergent laser beam 8, which is directed obliquely from above at an acute angle with respect to the longitudinal direction of the tool 5 onto the absorption surface 7 of the ultrasonic tool 1 formed in the end region 6 and heats the ultrasonic tool 1 in the area of the connecting contact surface 2. The incidence direction 9 of the laser beam 8 is oblique to the tool cover surface 4, which means that the laser beam does not impinge on the absorption surface 7 vertically.

[0054] FIG. 4 shows two temperature curves over time. Graph 14, represented by a dashed line, shows the temperature curve for the ultrasonic tool 1 according to FIG. 1. Compared to this, Graph 15, represented by the solid line, shows the temperature curve for an ultrasonic tool without an absorption surface that is identical in terms of macroscopic geometry and material.

[0055] Both ultrasonic tools 1 are irradiated by a laser beam 8 having the same wavelength, equal focusing and positioning and having the same, constant power. At the time to, the laser beam 8 is switched on and at the time ti, it is switched off. Starting from an ambient temperature, the two ultrasonic tools are heated by the laser beam 8.

[0056] The contrasting temperature curves clearly show that the heating of the inventive ultrasonic tool 1 with the absorption surface 7 is faster and that the inventive ultrasonic tool 1 is heated to a higher temperature than the conventional ultrasonic tool.

[0057] The ultrasonic tool 1 can be heated as shown by means of a laser beam 8 divergently impinging on the absorption surface 7. Alternatively, the ultrasonic tool 1—as shown in FIG. 5—can be irradiated with a collimated laser beam 8 or—as shown in FIG. 6—with a convergent laser beam 8.

[0058] FIGS. 7 and 8 show a second embodiment of the ultrasonic tool 1. The ultrasonic tool 1 according to FIG. 7 corresponds in large parts to the ultrasonic tool 1 in the first embodiment. However, in the area of the connecting contact surface 2, a V-shaped contact contour, which extends transversely to the longitudinal direction of the tool 5, for a bond wire is provided as a connecting component. During the preparation of a bond connection, the bond wire is provided in the V-shaped contact contour 10 and is pressed against a substrate.

[0059] FIGS. 9A-9D shows different types of microstructuring of the absorption surface 7. In FIG. 9A, the microstructured absorption surface 7 is formed by individual dot-shaped depressions or hollows. In contrast, the microstructure in FIG. 9B is formed by grooves that are oriented transversely to the longitudinal length of the tool 5, i.e., horizontally extended as is customary in the intended use of the ultrasonic tool 1. FIG. 9C also shows grooved microstructures of the absorption surface 7, which are arranged rotated by 90° as compared to the horizontal arrangement according to FIG. 9B. Finally, FIG. 9D shows grooved microstructures in which the grooves are arranged at 45° and crosswise.

[0060] FIG. 10 exemplifies a grooved surface structuring formed by a plurality of right triangles formed the same in cross-section. The depth T of the surface structures established vertically to the tool cover surface is greater than 1 μm. Preferably, the depth T of the surface structures is greater than 10 μm. A maximum depth T of the surface structures is 350 μm. These are therefore microstructures in the present example. The width B of the microstructures is preferably at most half the width of depth T.

[0061] FIG. 11 shows an enlarged sectional view of the microstructure according to FIG. 10, comprising three divergent laser beams impinging on the microstructure. The incident laser beams are repeated and, in the present example, partially reflected six to seven times when impinging on the absorption surface 7. After the repeated reflection, the laser beams leave the absorption surface 7 diffusely reflected and having a power that is orders of magnitude lower due to the repeated absorption.

[0062] FIGS. 12A-12E show a selection of different regular microstructures in cross-section. While FIGS. 12A, 12B, 12C and 12D show idealized geometries, FIG. 12E shows an example of a real microstructured absorption surface 7 produced by laser ablation with less sharp, rounded contour transitions.

[0063] The microstructures shown in FIGS. 9 to 12 are only examples. In principle, the microstructures can be freely designed. The microstructures can, for example, be regular or irregular or have an unspecified shape and/or variable structuring. Application-specific, material-dependent, and dependent on the operating parameters of the laser beam, the microstructure of the absorption surface can be designed in particular in such a way that there is a high and preferably regular absorption across the surface, and inadmissible local temperature peaks are avoided.

[0064] FIGS. 13 to 15 show a third embodiment of the inventive ultrasonic tool 1. The ultrasonic tool 1 is formed as an ultrasonic welding tool, which is formed symmetrically in respect of a transverse median plane 11 oriented perpendicular to the longitudinal direction of the tool 5. In addition, it is formed, as before, symmetrical in respect of the longitudinal center plane of the tool 13 which receives the longitudinal direction of the tool 5. The ultrasonic tool 1 provides a receptacle 12, which is designed in such a way that the ultrasonic tool 1 can be used in two orientations rotated by 180°. In this respect, it is an ultrasonic turning tool 1.

[0065] In the present ultrasonic tool 1, as before, the first end face 2 and additionally also the second end face 3′ of the ultrasonic tool 1 are formed as a connecting contact surface. In each case, the ultrasonic tool 1 tapers in the direction of the connecting contact surface 2, 3′. Each connecting contact surface 2, 3′ is part of an end region 6. From the connecting contact surfaces 2, 3′, the two opposing end regions 6 extend 15 mm in the longitudinal direction of the tool 5. They each provide an absorption surface 7, which is positioned adjacent to the first end face 2 or adjacent to the second end face 3′.

[0066] FIG. 16 shows how the laser beam 8 impinges on the absorption surface 7 associated with the first end face 2. The laser beam 8 heats the end region 6 with the connecting contact surface 2. In this case, the laser beam 8 is oriented in such a way that the incidence direction 9 of the laser beam 8 forms an acute angle with the longitudinal direction of the tool 5.

[0067] In principle, the representation of the geometry in the present case is only exemplary. Even if the surface structures are realized as microstructures in the discussed embodiments, macrostructures with a depth of more than 350 μm can also define the absorption surface.

[0068] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.