Ultrasonic bonding device and wire guiding module therefor

Abstract

The invention relates to an ultrasonic bonding device comprising a bonding head (1), wherein the bonding head (1) can be moved and / or positioned in at least one movement axis (41, 42, 43) and can be rotated and / or positioned about a rotational axis (40) and wherein the bonding head (1) has a tool (2) for the ultrasonic bonding of a bonding wire (15) and a transducer module (4) for exciting the tool (2) to produce ultrasonic vibrations, comprising a stationary wire supply for the bonding wire (15), comprising an elongate wire feed (7) that is cylindrical in cross section and preferably tubular and / or hose-like, comprising a first wire guiding module (10), wherein the first wire guiding module (10) has an inlet opening and an outlet opening for the bonding wire (15) and wherein the first wire guiding module (10) is associated with the tool (2) such that the bonding wire (15) emerging from the outlet opening is guided under the tool (2), and comprising a second wire guiding module (20), wherein the second wire guiding module (20) has an elongate guide channel (22) for the bonding wire (15), said second guide channel having an inlet opening (23) and an outlet opening (24), and wherein the second wire guiding module (20) is provided between the wire feed (7) and the first wire guiding module (10), wherein the first and the second wire guiding module (10, 20) are implemented as part of the bonding head (1) and on the bonding head (1) a holder (8) is provided by means of which an end of the wire feed (7) facing the second wire guiding module (20) is fixed on the bonding head (1). The invention also relates to a wire guiding module that can be used as a second wire guiding module (20) of an ultrasonic bonding device, and the use of the ultrasonic bonding device having the wire guiding module for ultrasonic ribbon bonding.

Description

[0001] Ultrasonic bonding device and wire guide module for this

[0002] The invention relates to an ultrasonic bonding device, a wire guide module which can be used as a wire guide module of the ultrasonic bonding device, and the use of the ultrasonic bonding device and / or the wire guide module for ultrasonic wire bonding and in particular ultrasonic ribbon bonding.

[0003] The wire guide module of an ultrasonic bonding device is used to reliably and collision-free guide the bonding wire provided in a wire supply beneath the tool of the ultrasonic bonding device. The tool and the wire guide module are designed as components of the bondhead and are moved with the bondhead. Depending on the design of the ultrasonic bonding device, the bondhead can be moved in up to three axes of movement oriented at right angles to one another and one axis of rotation. The axis of rotation and one axis of movement are typically vertical. Two other axes of movement of the ultrasonic bonding device are usually horizontal. The rotary supply of the ultrasonic bonding device is stationary and does not move with the bondhead. The bonding wire is therefore deformed and, in particular, twisted or otherwise bent when the bondhead is moved.The torsion or bending of the bond wire can cause it to exit the wire guide module in a geometrically indeterminate manner and not be positioned precisely under the tool. The subsequent bond may then not be executed properly or at all.

[0004] The object of the present invention is to provide an improved ultrasonic bonding device and a wire guide module therefor.

[0005] To achieve this object, the invention has the features of patent claim 1. Accordingly, the ultrasonic bonding device comprises a bondhead that can be moved and / or positioned in at least one movement axis and rotated and / or positioned about a rotation axis, and that provides a tool for ultrasonic bonding a bonding wire and a transducer module for exciting the tool to ultrasonic vibrations, as well as a stationary wire supply for the bonding wire. Furthermore, the ultrasonic bonding device comprises an elongated, cross-sectionally cylindrical and preferably tubular and / or hose-like wire feed, a first wire guide module that provides an inlet opening and an outlet opening for the bonding wire and that is assigned to the tool such that the bonding wire emerging from the outlet opening is guided beneath the tool.The ultrasonic bonding device further comprises a second wire guide module, which provides an elongated guide channel for the bonding wire with an inlet opening and an outlet opening and is located between the wire feed and the first wire guide module. The first and second wire guide modules are implemented as part of the bondhead. A holder is also provided on the bondhead, with which an end of the wire feed facing the second wire guide module is secured to the bondhead.

[0006] Optionally, as part of the ultrasonic bonding device, a wire buffer for the bonding wire is provided, which moves with the bonding head relative to the at least one movement axis and can be installed in a rotationally fixed manner with respect to the rotation axis. A wire feed module can be associated with the wire buffer, which is configured to convey the bonding wire from the stationary wire supply into the wire buffer.

[0007] The particular advantage of the invention is that by providing the second wire guide module, the bonding wire exits the first wire guide module torsion-free or virtually torsion-free and is positioned under the tool tip. This significantly reduces the risk of losing the bonding wire's association with the tool.

[0008] According to a further development of the invention, a distance of the guide channel from the axis of rotation of the ultrasonic bonding device changes in a direction of extension of the guide channel. In particular, the distance of the guide channel from the axis of rotation is smaller in the region of the inlet opening than in the region of the outlet opening. The distance of the bonding wire fed to the first wire guide module in the guide channel of the second wire guide module from the axis of rotation consequently increases during feeding. This makes it possible to feed the bonding wire to the first wire guide module without torsion or bending, in particular vertically from above, if the axis of rotation runs through the wire feed and the bonding tool and the inlet opening of the first wire guide module laterally assigned to the tool is provided outside the axis of rotation.

[0009] According to a further development of the invention, the inlet opening of the guide channel of the second wire guide module is provided coaxially with the rotation axis, or the rotation axis runs through the inlet opening of the guide channel of the second wire guide module. Advantageously, the bonding wire passes from the wire feed into the guide channel of the second wire guide module without additional twisting or bending if an end section of the wire feed facing the second wire guide module is provided coaxially with the rotation axis of the bondhead. The end section of the wire feed facing the second wire guide module is preferably fixed to the bondhead and moves along with it both translationally and rotationally.

[0010] To achieve this object, the invention has the features of patent claim 9. Accordingly, the wire guide module, which is used, for example, as a second wire guide module of the ultrasonic bonding device, comprises a monolithic module body that provides an elongated guide channel for a bonding wire with an inlet opening and an outlet opening. The guide channel is, in any case, partially closed on the casing side.

[0011] The particular advantage of the invention is that the module body, if it is monolithic, i.e., formed in one piece, can be manufactured cost-effectively. Furthermore, the storage and assembly of various module body components is eliminated. Since the module body and the wire guide module together constitute a wear part of the ultrasonic bonding device, the cost advantage is exponentially increased over the service life of the ultrasonic bonding device.

[0012] According to a further development of the invention, the module body is manufactured by primary forming. Preferably, the module body is manufactured using an additive manufacturing process. This primary forming process advantageously results in further cost advantages.

[0013] According to a further development of the invention, the module body provides receptacles for fastening means that serve to attach the wire guide module to an attachment part of the ultrasonic bonding device. For example, the module body provides fastening bushings as receptacles. A module carrier of the bonding head of the ultrasonic bonding device serves as an attachment part, for example. The receptacles can advantageously be designed as an integral component of the monolithic module body. This reduces assembly effort, and precise alignment of the receptacles relative to the guide channel with its inlet and outlet openings is eliminated.

[0014] According to a further development of the invention, the second wire guide module provides two opposing insertion surfaces for guiding the bonding wire, which taper in a funnel shape towards the outlet opening. For example, the guide surfaces are convexly curved and / or cylindrical segment-shaped. Preferably, two guide rollers are provided upstream of the inlet opening of the guide channel and are rotatably mounted relative to the module body. A gap for the bonding wire is formed between the guide rollers. The gap preferably has a constant gap width. Particularly preferably, the guide rollers have a cylindrical outer surface, which forms the insertion surfaces for the bonding wire. The provision of the tapered and, in particular, convexly curved or cylindrical segment-shaped guide surfaces advantageously reduces abrasion or wear on the wire guide module.This effect is further enhanced by the provision of guide rollers, as wear is distributed across the outer surface due to the rotating movement of the guide rollers. This significantly increases the service life of the wire guide module.

[0015] According to a further development of the invention, the width of the gap formed between the guide rollers is matched to the dimensions of the bonding wire. For example, the gap is 50 μm wider than the thickness or diameter of the bonding wire.

[0016] The ultrasonic bonding device and the wire module are used, for example, in ribbon bonding. The aluminum or copper ribbon typically has a width of 500 pm to 2000 pm and a thickness of 100 pm to 400 pm. For example, ribbons with cross-sections of 2000 pm x 300 pm or 1500 pm x 200 pm are used. The gap width is then 250 pm for the 200 pm thick ribbons or 350 pm for the 300 pm thick ribbons.

[0017] By keeping the gap only slightly wider than the ribbon's thickness, twisting of the ribbon is counteracted. This also reduces wear and prevents ribbon torsion.

[0018] Further advantages, features, and details of the invention can be derived from the further subclaims and the following description. The features mentioned therein can be essential to the invention individually or in any combination. Features and details of the ultrasonic bonding device described according to the invention naturally also apply in connection with the wire guide module, and vice versa. Thus, the disclosure of the individual aspects of the invention can always be referenced reciprocally. The drawings serve merely as examples to clarify the invention and are not limiting in nature.

[0019] Shown are: Fig. 1 a perspective partial view of a bondhead of an ultrasonic bonding device according to the invention with a wire guide module,

[0020] Fig. 2 is a side view of the partial representation of the bondhead according to Fig. 1,

[0021] Fig. 3 is a plan view of the partial representation of the bondhead according to Fig. 1,

[0022] Fig. 4 is an enlarged view of a detail X of the bondhead according to Fig. 3,

[0023] Fig. 5 the detail X according to Fig.3 with a bonding wire in the wire guide module,

[0024] Fig. 6 is a front view of the wire guide module of the bonding device according to Fig. 1,

[0025] Fig. 7 is a rear view of the wire guide module according to Fig. 6,

[0026] Fig. 8 is a first connection side view of the wire guide module according to Fig. 6,

[0027] Fig. 9 is a second connection side view of the wire guide module according to Fig. 6,

[0028] Fig. 10 is a bottom view of the wire guide module according to Fig. 6,

[0029] Fig. 11 is a plan view of the wire guide module according to Fig. 6,

[0030] Fig. 12 is a perspective view of the wire guide module of the bonding device according to Fig. 6 and

[0031] Fig. 13 shows a section AA through the wire guide module according to Fig. 6.

[0032] A bondhead 1 of an ultrasonic bonding device is partially shown in Figs. 1 to 3. Shown in particular are a tool 2 of the ultrasonic bonding device with a tool tip 3, a transducer module 4, which serves to excite the tool 2 to ultrasonic vibrations and on which the tool 2 is held by means of a tool holder 5, as well as a first wire guide module 10, a second wire guide module 20 and an end section of a tube-like or hose-like wire feed 7 facing the second wire guide module, through which end section a bonding wire 15, which is to be bonded by means of the tool 2 and is not shown in Figs. 1 to 3, is fed from a wire supply, likewise not shown, of the ultrasonic bonding device.

[0033] For clarity, other functional components of the ultrasonic bonding device and the bonding head 1 are not shown. These include, for example, a camera module and / or an illumination module and / or a knife module for severing the bonding wire 15 after bonding.

[0034] The bondhead 1 can be moved and positioned horizontally and vertically along three mutually orthogonal axes of movement 41, 42, 43. Furthermore, the bondhead 1 can be rotated and positioned about a vertical axis of rotation 40.

[0035] The first wire guide module 10 is laterally assigned to the tool 2. It serves to redirect the typically vertically fed bonding wire 15 and guide it under the tool tip 3 of the tool 2. The first wire guide module 10 provides an elongated guide channel for the bonding wire 15, which, where it is closed on the jacket side, is defined by two housing components of the first wire guide module 10.

[0036] The second wire guide module 20 is provided between the wire feed 7 and the first wire guide module 10. It provides an elongated guide channel 22 with an inlet opening 23 for the bonding wire 15 facing the wire feed 7 and with an outlet opening 24 facing the first wire guide module 10.

[0037] Detail X according to Fig. 3 is shown enlarged in Fig. 4 without the bonding wire 15 and in Fig. 5 with the bonding wire 15. It can be seen that the wire feed 7 is arranged in alignment with the inlet opening 23 of the second wire guide module 20 and the bonding wire 15 is fed essentially centrally or centrically to the inlet opening 23. An end section of the wire feed 7 facing the second wire guide module 20 is fixed to the module carrier 6 of the bondhead 1 via a holder 8. A clamping screw 9 is used to secure the wire feed 7 to the holder 8.

[0038] Figures 6 to 13 show various views and a longitudinal section through the second wire guide module 20 of the ultrasonic bonding device. The second wire guide module 20 provides a monolithic module body 21 that provides the elongated guide channel 22. The bonding wire 15 (not shown) enters the guide channel 22 through an inlet opening 23 and exits it through the outlet opening 24.

[0039] Two guide rollers 25, 26 are provided upstream of the inlet opening 23 of the guide channel 22. These guide rollers are supported on the module body 21 via two parallel pins 31, 32 and are rotatable relative to the module body 21. The guide rollers 25, 26 have a cylindrical outer surface and a constant distance from one another. A gap 27 for the bonding wire 15 is formed between the guide rollers 25, 26. The gap 27 has a constant gap width. The gap width is slightly larger than the thickness of the bonding wire 15. For example, the gap 27 is 50 μm wider than the thickness of the bonding wire 15.

[0040] The monolithic module body 21 is manufactured from a plastic material using an additive manufacturing process. To enable the powdered or granular raw material from which the module body 21 is made to be removed from the guide channel 22 of the module body 21 after production, the module body 21 is provided with a window-like, elongated recess 33 extending to the guide channel 22. The raw material can be removed from the guide channel 22 via the recess 33.

[0041] A total of three mounting bushings 28, 29, 30 are provided on the module body 21. The mounting bushings, with their cylindrical through-holes, serve as receptacles for fastening means, which in turn serve to fasten the second wire guide module 20 to the module carrier 6 of the bonding head of the ultrasonic bonding device. Screws, for example, are provided as fastening means. The guide channel 22 has a substantially rectangular cross-section. The cross-section is largest where the recess 33 is provided. It tapers both toward the inlet opening 23 and toward the outlet opening 24.

[0042] Identical components and component functions are identified by the same reference symbols.

[0043] List of reference symbols

[0044] 1 bond head

[0045] 2 tools

[0046] 3 tool tip

[0047] 4 Transducer module

[0048] 5 Tool holder

[0049] 6 module carriers

[0050] 7 Wire feed

[0051] 8 Bracket

[0052] 9 clamping screw

[0053] 10 first wire guide module

[0054] 15 bonding wire

[0055] 20 second wire guide module

[0056] 21 module bodies

[0057] 22 guide channel

[0058] 23 Entrance opening

[0059] 24 Exit opening

[0060] 25 Leadership role

[0061] 26 Leadership role

[0062] 27 gap

[0063] 28 Mounting bushing

[0064] 29 Mounting bushing

[0065] 30 mounting bushing

[0066] 31 pen

[0067] 32 pin

[0068] 33 Recess

[0069] 40 axis of rotation

[0070] 41 Movement axis

[0071] 42 Movement axis

[0072] 43 Movement axis

Claims

Patent claims 1. Ultrasonic bonding device comprising a bonding head (1), wherein the bonding head (1) is movable and / or positionable in at least one axis of movement (41, 42, 43) and rotatable and / or positionable about a rotational axis (40), and wherein the bonding head (1) provides a tool (2) for ultrasonic bonding of a bonding wire (15) and a transducer module (4) for exciting the tool (2) to ultrasonic vibrations, comprising a stationary wire supply for the bonding wire (15), comprising an elongated, cylindrical in cross-section and preferably tube- and / or hose-like wire feed (7), comprising a first wire guide module (10), wherein the first wire guide module (10) provides an inlet opening and an outlet opening for the bonding wire (15), and wherein the first wire guide module (10) is associated with the tool (2) such that the bonding wire (15) exiting the outlet opening is guided under the tool (2). is guided, and includes a second wire guidance module (20),wherein the second wire guide module (20) provides a longitudinally extended guide channel (22) for the bond wire (15) with an inlet opening (23) and an outlet opening (24) and wherein the second wire guide module (20) is provided between the wire feed (7) and the first wire guide module (10), wherein the first and the second wire guide modules (10, 20) are implemented as part of the bond head (1) and wherein a holder (8) is provided on the bond head (1) with which an end of the wire feed (7) facing the second wire guide module (20) is fixed to the bond head (1).

2. Ultrasonic bonding device according to claim 1, characterized in that the distance of the guide channel (22) to the axis of rotation (40) changes in an extension direction of the guide channel (22) and / or that the distance of the guide channel (22) to the axis of rotation (40) is smaller in the area of ​​the inlet opening (23) than in the area of ​​the outlet opening (24). Ultrasonic bonding device according to claim 1 or 2, characterized in that the inlet opening (23) of the guide channel (22) of the second wire guide module (20) is provided coaxially with the axis of rotation (40). Ultrasonic bonding device according to any one of claims 1 to 3, characterized in that a wire intermediate storage unit for the bonding wire (15) is provided, which moves with the bonding head (1) with respect to the at least one axis of movement (41, 42, 43) and is installed in a rotationally fixed manner with respect to the axis of rotation (40). Ultrasonic bonding device according to claim 4, characterized in that a wire feed module is provided, wherein the wire feed module is configured to feed the bonding wire (15) from the stationary wire supply into the wire intermediate storage unit.Ultrasonic bonding device according to any one of claims 1 to 5, characterized in that the tool (2) and / or an end section of the wire feed (7) facing the second wire guide module (20) extend longitudinally in the direction of the axis of rotation (40) and / or are arranged coaxially to each other and / or coaxially to the axis of rotation (40). Ultrasonic bonding device according to any one of claims 1 to 6, characterized in that the bonding head (1) provides a module carrier (6) on which the holder (8) for the wire feed (7) and the second wire guide module (20) are mounted adjacent to each other. Ultrasonic bonding device according to claim 7, characterized in that the transducer module (4) and / or the first wire guide module (10) are held on the module carrier (6).Wire guide module (20) for an ultrasonic bonding device, in particular for an ultrasonic bonding device according to one of claims 1 to 8, comprising a monolithic module body (21), wherein the module body (21) provides an elongated guide channel (22) for a bonding wire (15) with an entry opening (23) and with an exit opening (24) and wherein the. The guide channel (22) is at least partially closed on the outer surface. A wire guide module (20) according to claim 9, characterized in that the module body (21) is formed by primary forming and preferably by an additive manufacturing process. A wire guide module (20) according to claim 9 or 10, characterized in that a recess (33) leading to the guide channel (22) is provided on the module body (21), wherein the recess (33) is spaced apart from the inlet opening (23) and / or the outlet opening (24) and / or is preferably designed as an elongated recess (33) extending longitudinally in a direction of extension of the guide channel (22).Wire guide module (20) according to any one of claims 9 to 11, characterized in that two opposing and funnel-shaped, preferably convexly curved and / or cylindrical segment-shaped, insertion surfaces are provided for inserting the bond wire (15) into the guide channel (22). Wire guide module (20) according to any one of claims 9 to 12, characterized in that two guide rollers (25, 26) are provided upstream of the inlet opening (23) of the guide channel (22), which are rotatably held relative to the module body (21), and that a gap (27) is formed between the guide rollers (25, 26), which preferably has a constant gap width. Wire guide module (20) according to claim 13, characterized in that the guide rollers (25, 26) have a cylindrical outer surface and that the outer surfaces of the guide rollers (25, 26) form the insertion surfaces for the bond wire (15).Wire guide module (20) according to one of claims 9 to 14, characterized in that a cross-sectional shape of the guide channel (22) changes in the extension direction thereof and / or the guide channel (22) in. The wire guide module (20) according to any one of claims 9 to 15 is characterized in that the guide channel (22) has a minimum cross-sectional area in the region of the outlet opening (24) and / or that the cross-section of the guide channel (22) tapers towards the inlet opening (23) and towards the outlet opening (24). The wire guide module (20) according to any one of claims 9 to 16 is characterized in that the guide channel (22) has a rectangular cross-sectional shape at least in the region of the outlet opening (24) and preferably over its entire length. The wire guide module (20) according to any one of claims 9 to 16 is characterized in that the module body (21) provides receptacles for fastening means that serve to fasten the wire guide module (20) to an attachment part of the ultrasonic bonding device. The wire guide module (20) according to claim 17 is characterized in that the module body (21) provides fastening bushings (28, 29, 30) as receptacles.Wire guide module (20) according to any one of claims 9 to 18, characterized in that the module body (21) and / or the guide rollers (25, 26) are made of plastic. Use of a wire guide module (20) according to any one of claims 9 to 19 as a second wire guide module (20) of an ultrasonic bonding device according to any one of claims 1 to 8. Use of an ultrasonic bonding device according to any one of claims 1 to 8 and / or a wire guide module (20) according to any one of claims 9 to 19 for ultrasonic ribbon bonding.

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