BONDING ARRANGEMENT AND BONDING TOOL

Abstract

A bonding arrangement comprising a bonding tool, having a tool shank which is designed to extend in a longitudinal direction of the tool, and a tool tip which connects to the tool shank. A first end side of the bonding tool is provided on the tool tip, which is designed to come into contact with a connection part. A second end side of the bonding tool is provided on the tool shank. The bonding tool has a casing surface connecting the first end side and the second end side, said bonding arrangement comprising a laser generator for providing a laser beam and comprising a light guide designed to guide the laser beam to the bonding tool. A functional recess is formed on the bonding tool on the casing side and the light guide is associated with the bonding too on the casing side from the outside and at a distance.

Claims

1. A bonding arrangement comprising: a bonding tool having a tool shank which is designed to extend in a longitudinal direction of the tool and having a tool tip which connects to the tool shank; a first end side of the bonding tool provided on the tool tip, which is designed to come into contact with a connection part; a second end side of the bonding tool provided on the tool shank, the bonding tool comprises a casing surface connecting the first end side and the second end side; a laser generator to provide a laser beam; a light guide to guide the laser beam to the bonding tool; and a functional recess formed on the bonding tool on the casing side, wherein the light guide is associated with the bonding tool on the casing side from an outside and at a distance such that the laser beam coupled out via an end side of the light guide facing the functional recess impinges on the bonding tool in the functional recess.

2. The bonding arrangement according to claim 1, wherein the functional recess is designed as a beam trap such that at least one boundary surface of the functional recess is formed as a deflection surface for the laser beam and has an angle of attack deviating by 0° and 90° to a direction of incidence of the laser beam and/or is curved.

3. The bonding arrangement according to claim 1, wherein the functional recess is at least partially formed on the tool tip (4).

4. The bonding arrangement according to claim 1, wherein the functional recess tapers towards the first end side and/or the first end side and/or the second end side are designed as a closed surface.

5. The bonding arrangement according to claim 1, wherein the functional recess is prepared by wire EDM and/or by die-sinking EDM and/or by additive manufacturing processes and/or by primary forming and/or machining.

6. The bonding arrangement according to claim 1, wherein the light guide comprises a glass fiber or a glass fiber bundle and/or that the light guide and/or the glass fiber (s) is coated with a reflection coating on the outside, at least in sections.

7. The bonding arrangement according to claim 1, wherein a width determined transversely to the longitudinal direction of the tool of the functional recess is always smaller than two thirds and preferably smaller than half of a corresponding width of the bonding tool.

8. The bonding arrangement according to claim 1, wherein the bonding tool with the functional recess is symmetrically formed to a median longitudinal plane of the bonding tool and/or wherein a cross-section of the functional recess is in any case constant in sections.

9. The bonding arrangement according to claim 1, wherein the functional recess is pocket-shaped.

10. The bonding arrangement according to claim 1, wherein the functional recess is designed as a through recess.

11. The bonding arrangement according to claim 1, wherein the width of the bonding tool in the area of the tool tip decreases in the direction of the first end side and/or wherein a bond contact surface is provided on the first end side for the connection part.

12. The bonding arrangement according to claim 1, wherein an ultrasonic generator is provided and that the ultrasonic generator interacts with the bonding tool in such a way that the bonding tool is excited to ultrasonic vibration or to ultrasonic bending vibration by the ultrasonic generator.

13. The bonding arrangement according to claim 1, wherein between the direction of incidence of the laser beam and the longitudinal direction of the tool an angle of incidence of a maximum of 90° and preferably of 60° or less and particularly preferably of 30° +/− 10° is formed.

14. A bonding tool for a bonding arrangement according to claim 1, the bonding tool comprising: a tool shank which is designed to extend in a longitudinal direction of the tool; and a tool tip that connects to the tool shank, wherein a first end side of the bonding tool is provided on the tool tip, which is designed to come into contact with a connection part, wherein a second end side of the bonding tool with a closed surface is provided on the tool shank, wherein the bonding tool has a casing surface connecting the first end side and the second end side, and wherein a functional recess is formed on the bonding tool on the casing side.

15. The bonding arrangement according to claim 1, wherein the bonding arrangement is provided for laser-supported ultrasonic bonding or for laser-supported ultrasonic wire bonding.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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:

[0025] FIG. 1 is a front view of a bonding tool according to the invention having a functional recess formed on the casing side, which is designed as a through recess in the area of the tool tip of the bonding tool, in a first embodiment,

[0026] FIG. 2 is a detail X of the bonding tool according to FIG. 1 in an enlarged representation,

[0027] FIG. 3 is a longitudinal side view of the bonding tool according to FIG. 1,

[0028] FIG. 4 is a view of the underside of the bonding tool according to FIG. 1,

[0029] FIG. 5 is a perspective view of the inventive bonding tool according to FIG. 1 with a representation of a laser beam impinging on the functional recess with a focused beam path,

[0030] FIG. 6 is a side view of the bonding tool with the laser beam according to FIG. 5,

[0031] FIG. 7 is a side view of the bonding tool with the laser beam with a collimated beam path,

[0032] FIG. 8 is a side view of the bonding tool with the laser beam with a divergent beam path,

[0033] FIG. 9 is a second embodiment of the inventive bonding tool in a front view,

[0034] FIG. 10 is the bonding tool according to FIG. 9 in a longitudinal side view,

[0035] FIG. 11 is the bonding tool according to FIG. 9 in a view of the underside and

[0036] FIG. 12 is a third embodiment of the bonding tool of the invention in a front view.

DETAILED DESCRIPTION

[0037] An inventive bonding tool according to FIGS. 1 to 4 provides a tool shank 3, which is extended in a longitudinal direction of the tool 10. Furthermore, the bonding tool 1 provides a tool tip 4 which connects to the tool shank 3. The tool tip 4 of the bonding tool 1 has a first end side 17. A second end side 6 is provided on the tool shank 3, opposite the first end side 17. The second end side 6 has a closed surface, i.e., is designed without a recess or opening. In the area of the second end side 6, the bonding tool 1 is held in receptacle of the bonding machine during bonding. In addition, the bonding tool 1 has a casing surface connecting the first end side 17 and the second end side 6.

[0038] On the first end side 17 is a receiving slot which extends transversely to the longitudinal direction of the tool 10. The receiving slot is designed to accommodate a bond wire, which serves as a connection part during bonding. In the area of the receiving slot, the bonding tool 1 comes into contact with the bond wire on the casing side when the bond connection is established with a bond contact surface 7.

[0039] In the area of the tool tip 4, moreover, a functional recess 8 is formed. The functional recess 8 is formed on the casing surface 16 of the bonding tool 1. The functional recess 8 is designed as a through recess. It is orthogonally oriented to the longitudinal direction of the tool 10.

[0040] The functional recess 8 has a constant width 12 in an area facing the second end side 6 or the tool shank 3 and then tapers wedge-shaped in the direction of the underside 17 of the tool tip 4. In the area of the wedge-shaped tapering, two opposing boundary surfaces 9 of the functional recess 8 are formed as absorption or deflection surfaces for a laser beam 2. The deflection surfaces 9 are flat and arranged inclined at an acute angle of attack 15 to the longitudinal direction of the tool 10.

[0041] In the present embodiment of the invention, a width 12 of the functional recess 8 orthogonally determined to the longitudinal direction of the tool 10 is in each case smaller than two thirds of a corresponding external width 11 of the bonding tool 1. Therefore, the bonding tool 1 always provides for sufficient material in the area of the functional recess 8 to ensure adequate mechanical stability.

[0042] In terms of a median longitudinal plane 13 of the bonding tool 1, the latter is symmetrically formed. The symmetry promotes the vibration properties of the bonding tool 1.

[0043] FIGS. 5 and 6 show the bonding tool 1, while the laser beam 2, which is provided by a laser generator of the inventive bonding arrangement impinges on the bonding tool 1 obliquely from above in the area of the functional recess 8. An acute angle of incidence of about 30° is formed between an incidence direction 5 of the laser beam 2 and the longitudinal direction of the bonding tool 10.

[0044] The laser beam 2, which is provided by the laser generator, is guided to the bonding tool via a light guide. While the laser generator is preferably arranged stationary, preferably at least a part of the light guide will be fixed to a movably held bonding head of the bonding machine serving the positioning of the bonding tool 1 and will be moved as well when positioning the bonding head. The light guide is distanced from the bonding tool 1 and associated with said bonding tool on the casing side from the outside and positioned such that the laser beam 2 coupled out via an end side of the light guide facing the functional recess impinges on the bonding tool 1 in the functional recess 8 and heats said bonding tool, in particular in the area of the tool tip 4.

[0045] The laser beam 2 is focused. For focusing the usually divergent laser beam 2 exiting the light guide, for example, a focusing lens or another suitable beam-forming optical unit is arranged in the beam path of the laser beam 2 between the light guide and the bonding tool 1.

[0046] FIG. 7 shows a side view of the bonding arrangement according to the invention having the bonding tool 1 and the laser beam 2, which, as before, impinges on the bonding tool in the functional recess 8. The laser beam 2 has, in the present case, a collimated beam path, i.e., one which is directed at least approximately parallel. For this purpose, for example, a collimator optical unit is provided in the beam path of the laser beam.

[0047] In FIG. 8, a diverging laser beam 2 is provided by means of the bonding arrangement of the invention, which impinges on the bonding tool in the known manner in the functional recess 8. Since the laser beam 2 is usually coupled out divergently from the light guide of the bonding arrangement, a beam-forming optical unit in the beam path of the laser beam 2 can be dispensed with.

[0048] A first alternative embodiment of the inventive bonding arrangement is shown in FIGS. 9 to 11. In this case, the bonding tool has a congruently formed functional recess 8 that is now pocket or trough shaped. Thus, the functional recess 8 is not designed as a through recess. It is bordered on the front by a wall 18 and open to a back side. In this respect, the laser beam 2 will be directed from the back side into the functional recess 8. Otherwise, the bonding arrangement corresponds to the one discussed above.

[0049] While according to the first two exemplary embodiments of the invention the functional recess 8 tapers wedge-shaped in the direction of the first end side 17 of the tool tip 4, the third embodiment of the invention shown in FIG. 12 has a functional recess 8 which is rectangular in cross-section, the width 12 being constant in the longitudinal direction of the tool 10. As before, the functional recess 8 is fully arranged in the area of the tool tip 4 and designed as a through recess. Of course, it may be provided here alternatively that the functional recess 8 is pocket-shaped.

[0050] The width 12 of the functional recess 8 may increase in sections in the direction of the underside 17. For example, the functional recess 8 can be cone-shaped or frustum-shaped. For example, the width 12 of the functional recess 8 may be determined in such a way that the laser beam does not impinge on the lateral boundary surfaces of the functional recess 8, but instead impinges on a lower boundary surface of the functional recess 8 which is associated with the first end side 17 of the bonding tool 1.

[0051] 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.