Method for operating an ultrasonic connection device
By using a movable ultrasonic head and sensor to detect bonding force in an ultrasonic connection device, the contact moment can be accurately determined, solving the problem of monitoring the contact moment between the connecting conductor and the connection area, and improving connection quality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HESSE
- Filing Date
- 2021-12-20
- Publication Date
- 2026-05-12
AI Technical Summary
During ultrasonic connection, it is difficult to accurately monitor and control the contact time between the connecting conductor and the connection area, which makes it difficult to guarantee the connection quality and efficiency, especially when there is an unknown gap between the connecting conductor and the connection area.
An ultrasonic head that can move in the z-direction is used. By determining the moving position and relative position of the ultrasonic head, and combining the bonding force and support force detected by sensors, the contact moment is accurately determined, thereby controlling the connection process.
It enables precise control and monitoring of the connection process, ensuring the reliability of material locking connections, improving connection quality and production efficiency, and reducing unnecessary process time.
Smart Images
Figure CN116887940B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for operating an ultrasonic connection device and its application in the connection of electrical contacts of components in power electronic devices. Background Technology
[0002] Known methods for connecting conductive components using ultrasonic waves often specify that the components to be connected are placed close together and pressed against each other. At least one component is then excited to vibrate within the ultrasonic range using an ultrasonic tool, thereby forming a material-locked connection between the components. The quality and characteristics of the electrical connection established in this way are decisively determined by the vibration parameters, particularly the frequency and amplitude, and the process force with which the components are pressed against each other during connection establishment.
[0003] Depending on the characteristics and configuration of the components and the connection assemblies used to establish conductive connections between them, the components to be connected do not initially come into direct contact or abut each other. Whenever, for example, a connecting conductor, particularly a load current connecting conductor with a relatively thick cross-section, must be connected to a power electronic device structural assembly, the connecting conductor is initially positioned above the connection area of the power electronic assembly. Here, due to manufacturing tolerances, a gap of unknown size is typically formed between the connecting conductor and the connection area. The connecting conductor is pressed against the connection surface of the connection area by the ultrasonic tool only when the ultrasonic tool descends, and therein undergoes elastic deformation. Therefore, a portion of the bonding force applied by the ultrasonic tool is necessary to deform the connecting conductor even before the manufacturing materials lock together.
[0004] To ensure that ultrasonic connections are reliably manufactured with consistent high quality over a short period of time, accurate understanding and monitoring of process parameters are crucial. To determine, for example, the duration of ultrasonic wave action, it is necessary to know when the gap between the connecting conductor and the connection area closes and when the two components come into contact. Furthermore, understanding the time-varying curves of the process forces acting between the components allows for monitoring the connection process and inferring the quality or grade of the ultrasonic connection from these process parameters. Summary of the Invention
[0005] Therefore, the objective of this invention is to provide an improved operating method for an ultrasonic connection device.
[0006] To address this task, the present invention proposes a method for operating an ultrasonic connection device, wherein the ultrasonic connection device is provided with an ultrasonic head movable in the z-direction, the ultrasonic head having a support, an ultrasonic generating device movably held on the support relative to the support, and an ultrasonic tool excited by the ultrasonic generating device to vibrate ultrasonically, the method comprising the following steps:
[0007] —A conductive connecting conductor is positioned above a conductively constructed connecting region disposed on a connecting member, such that a gap with a defined gap size in the z-direction is formed between the connecting conductor and the connecting surface of the connecting region facing the connecting conductor.
[0008] — Position the ultrasonic head relative to the connecting conductor and the connecting member such that the ultrasonic tool is configured such that the contact surface against the connecting conductor faces the connecting conductor.
[0009] —Apply a bonding force in the z-direction to the ultrasonic wave generating device and press it against the support.
[0010] Then
[0011] —The ultrasonic head is lowered in the z-direction, and the position of the ultrasonic head in the z-direction and the relative position of the ultrasonic generating device with respect to the support in the z-direction are determined.
[0012] —Determine the contact moment by taking into account the moving position and the relative position, at which the connecting conductor is lowered by the ultrasonic tool to the extent that it contacts the connecting area of the connecting member.
[0013] Therefore, a method for operating an ultrasonic connection device, the ultrasonic connection device being provided with an ultrasonic head movable in the z-direction, the ultrasonic head being provided with a support, an ultrasonic generating device movably held on the support relative to the support, and an ultrasonic tool excited by the ultrasonic generating device to vibrate ultrasonically, the method comprising the following steps:
[0014] —The conductive connecting conductor is positioned above the conductively constructed connecting region on the connecting member such that a gap with a defined gap size in the z-direction is formed between the connecting conductor on one side and the connecting surface of the connecting region on the other side facing the connecting conductor.
[0015] The ultrasonic head is positioned relative to the connecting conductor and the connecting member above the connecting conductor in such a way that the contact surface of the ultrasonic tool against the connecting conductor faces the connecting conductor.
[0016] —Apply a bonding force in the z-direction to the ultrasonic wave generating device and press it against the support.
[0017] —Then the ultrasonic head is lowered in the z-direction, the moving position of the ultrasonic head in the z-direction and the relative position of the ultrasonic generating device with respect to the support in the z-direction are determined, and the contact moment is determined from the moving position of the ultrasonic head and the relative position of the ultrasonic generating device with respect to the support, at which time the connecting conductor is lowered by the ultrasonic tool to the extent that it contacts the connecting area of the connecting member.
[0018] A particular advantage of this invention is that the process duration can be determined by knowing the contact moment, during which energy introduced into the connection site via ultrasonic vibration facilitates the material-locking connection between the conductor and the connecting member. In this respect, the connection process can be precisely implemented and controlled or monitored, resulting in a reliable material-locking connection or the identification of connection errors. Safety precautions regarding the process duration can be avoided or reduced, ultimately increasing yield and improving the economics of the method.
[0019] According to a preferred embodiment of the invention, the contact moment is determined by measuring the difference between the time change of the moving position of the ultrasonic head and the time change of the relative position of the ultrasonic generating device, and identifying the zero value of the difference. If, on the one hand, the time change of the moving position and on the other hand, the time change of the relative position are of the same magnitude, the ultrasonic generating device moves away from the support at the same speed as the descent speed of the ultrasonic head. This is the case when the connecting conductor is in contact with the connecting surface of the connecting area and has not yet been deformed.
[0020] According to a further improvement of the invention, the contact moment is determined on the one hand by the bonding force and the supporting force pressing the ultrasonic generating device against the support, or by the closing force applied to close the gap between the connecting conductor and the connecting member, and on the other hand by the process force acting between the connecting conductor and the connecting member. In particular, the process force is determined as the difference between the bonding force and the supporting or closing force. Advantageously, knowing the process force allows for targeted and precise influence or monitoring of the connection process. The application of a minimum process force can also be ensured by methodologically depicting a process force-time variation curve that proves advantageous for a specific connection task. Here, for example, specific material parameters, the cross-sectional shape, or the diameter of the connecting conductor can be considered.
[0021] For example, the supporting force between the ultrasonic generating device and the support can be sensed. The closing force can be determined, for example, as the bonding force at the moment of contact.
[0022] For example, the method according to the invention is used to connect a load current connecting conductor to a connecting component of a power electronic device structural assembly. Due to the relatively high current, the connecting conductor used for this purpose has a relatively large cross-section, thus pushing conventional bonding methods (in which the connecting conductor is continuously delivered via an ultrasonic head) to their limits. Alternatively, the connecting conductor is cut or pre-shaped and operated individually. It is then positioned such that it is positioned above the connecting region and forms a gap of unknown size between the connecting conductor and the connecting region. Attached Figure Description
[0023] Further advantages, features, and details of the invention will become apparent from the following description. The features mentioned therein may be important to the invention individually or in any combination. The accompanying drawings are provided illustratively only to clarify the invention and are not intended to limit its scope.
[0024] The attached diagram shows:
[0025] Figure 1 This diagram illustrates the principle of the ultrasonic head of the ultrasonic connection device before establishing an ultrasonic connection.
[0026] Figure 2 This shows the process of manufacturing ultrasonic connection devices according to... Figure 1 The ultrasonic head of the ultrasonic connector.
[0027] Figure 3 The diagram shows different velocity-time curves when establishing an ultrasonic connection for the first connection scenario.
[0028] Figure 4 The diagram shows different force-time curves for the first connection case, and...
[0029] Figure 5 The diagram shows different speed-time curves when manufacturing the connecting components for the second connection scenario. Detailed Implementation
[0030] An ultrasonic connection device suitable for implementing the method according to the invention includes an ultrasonic head 1, which is movable in the z-direction. The ultrasonic head 1 is provided with a support 2 and an ultrasonic generating device 3 movably held relative to the support 2. In the present case, an ultrasonic tool 4, extending longitudinally in the z-direction and tapering in a wedge shape at its free end away from the ultrasonic generating device 3, is fixed to the ultrasonic generating device 3. The ultrasonic generating device 3 includes, for example, a piezoelectric ceramic element or a transducer, which excites the ultrasonic tool 4 to mechanically vibrate in the ultrasonic range due to an electrical input signal.
[0031] According to Figure 1In the initial configuration, the ultrasonic head 1 is positioned above the conductive connection region 8 constructed on the connecting member 7. The connecting conductor 6 is positioned between the contact surface 5 of the ultrasonic tool 4 facing the connection region 8 and the connection region 8. The connecting conductor 6 is, for example, a load current connecting conductor, which is material-locked to the connection region 8 of the connecting member 7 by means of an ultrasonic connection device. Here, the connection surface 9 of the connection region 8 faces the connecting conductor 6.
[0032] In the initial configuration, the connecting conductor 6 is positioned spaced apart from the connecting member 7, such that a gap 10 with a gap dimension s extending in the z-direction is formed between the connecting region 8 of the connecting member 7 and the connecting conductor 6. Furthermore, the connecting conductor 6 is positioned at a distance from the ultrasonic tool 4.
[0033] Figure 2 The ultrasonic connection device is shown during the establishment of an ultrasonic connection. Here, the connecting conductor 6 is pressed against the connecting surface 9 of the connection region 8 by an ultrasonic tool 4 that rests against the connecting conductor 6 with its contact surface 5. The ultrasonic tool 4 is excited to vibrate by the ultrasonic generating device 3 and is loaded with a bonding force acting in the z-direction. Here, the ultrasonic head 1 moves or descends in the z-direction to such an extent that the ultrasonic generating device 3 is positioned at a distance from the support 2.
[0034] For the first connection case, refer to the following Figure 1 and Figure 2 With the help of Figure 3 and Figure 4 The velocity-time and force-time variation curves illustrate the working principle of the operating method according to the present invention.
[0035] From according to Figure 1 Starting from the configuration, the ultrasonic head 1 descends in the z-direction. Through this descent, contact is first formed between the contact surface 5 of the ultrasonic tool 4 and the connecting conductor 6 at the aspiration time t0. The elastically deformable connecting conductor 6 is aspirated by the ultrasonic tool 4 and thus descends toward the connecting surface 9 of the connecting region 8. Therefore, contact is first formed between the connecting conductor 6 and the connecting region 8 at the contact time t1.
[0036] For connection case 1, assuming the applied bonding force Greater than the closing force applied to close the gap 10 Here, the bonding force It is constant, while the closing force is constant. As the connecting conductor 6 is from Figure 1 Deflection in the rest position shown It increases linearly. Therefore, the closing force... It varies over time. It is determined by the following formula:
[0037]
[0038] Here, This can be understood as the unknown spring constant connecting conductor 6.
[0039] Furthermore, it is assumed that the ultrasonic head 1 moves slowly and at a constant speed. It descends in the z-direction. Velocity Here is the time derivative of the position z of the ultrasonic head 1 in the z-direction. Therefore, the following explanation takes a quasi-static process as its starting point. It is also assumed that the components of the ultrasonic head 1, including the ultrasonic tool 4 and the base, are ideally rigid. Therefore, the velocity changes at the moment of aspiration t0 and the moment of contact t1 can be considered as a jump.
[0040] If the ultrasonic head 1 descends in the z-direction, then the position z of the ultrasonic head 1 will move at an assumed constant speed. Change. Because the bonding force is assumed for the first connection case. Greater than the closing force Therefore, the speed of ultrasonic tool 4 in the z direction Corresponding to the speed of ultrasonic head 1 The relative movement between the support 2 and the ultrasonic generating device 3 (the ultrasonic tool 4 is held on the ultrasonic generating device 3) does not occur until the gap 10 closes. Once the gap 10 closes at the contact moment t1, the ultrasonic tool 4 remains stationary.
[0041] Alternatively, if we observe the deformation of connecting conductor 6, which remains stationary until the agitation time t0, its deflection... With deformation speed The same applies until the carrying time t0 reaches zero. From the carrying time t0, the gap 10 moves at a certain speed.
[0042]
[0043] Closure. At contact time t1, connecting conductor 6 rests against the connecting surface 9 of connecting region 8. Its velocity... With the speed of ultrasonic tool 4 From that moment onward, the same value is zero.
[0044] From the contact moment t1, the ultrasonic head 1 descends further in the z-direction, and the ultrasonic generating device 3 detaches from the support 2. In this respect, the relative position between the support 2 and the ultrasonic generating device 3 can be determined using measurement techniques. The speed at which the ultrasonic generating device 3 moves away from the support 2. Corresponding to the speed at which the ultrasonic head 1 descends in the z-direction Therefore, the velocity difference Δv is zero from the contact time t1. Thus, the velocity difference can be determined using the method according to the invention.
[0045]
[0046] Determine the contact time t1. For this purpose, the ultrasonic connection device is equipped with a suitable measuring device, such as a displacement sensor.
[0047] Because of the spring constant connecting conductor 6 Since the position 6 of the ultrasonic head 1 at contact time t1 is unknown, the closing force cannot be determined. Alternatively, measure the support force. The ultrasonic generator 3 is pressed against the support 2 by this supporting force. For this purpose, the ultrasonic generator can be equipped with suitable measuring devices, such as a force sensor. The force is measured during the subsequent placement process. Therefore, the corresponding support force at time t1, directly before placement, is... The relevant closing force at time t1 It can pass through
[0048]
[0049] The calculations can therefore be taken into account during the establishment of a conductive, material-locked connection between the connecting conductor 6 and the connecting structure 7, because of the process forces. Applicable
[0050]
[0051] For the second connection case, assume the closing force This is greater than the force initially applied in the z-direction by the ultrasonic head 1. The initial applied force is understood below as the fundamental bonding force component. .
[0052] If the fundamental force components of the bond The closing force required to close a gap smaller than 10 Therefore, the ultrasonic generating device 3, which is movably held on the support relative to the support 2, detaches from the support 2 before the gap 10 is completely closed. (Except for the bonding fundamental force component) In addition, a bonding displacement force component is applied here, which, along with the bonding fundamental force component, Together, they constrain the bond force acting in the z-direction. .
[0053] Assume the bond displacement force component passes through a linear spring characteristic curve. Description. Here, Known or experimentally determined machine constants of the ultrasonic connection device are defined, for example by the elasticity of the ultrasonic generating device 3 suspended on the support 2.
[0054] Now consider the bonding force pre-defined by the ultrasonic bonding device.
[0055]
[0056] In the second connection case, it depends linearly on the relative position between the support 2 and the ultrasonic generating device 3. Bonding force It increases linearly, wherein the gap 10 is always reliably closed before the contact time t1.
[0057] Force balance is effective at any point during the closing process.
[0058]
[0059] or
[0060]
[0061] And therefore, by differentiating the velocity relationship during the compression connection of conductor 6:
[0062]
[0063] The sum of the speeds gives the speed at which the ultrasonic head 1 descends. ,:
[0064]
[0065] Therefore, speed is divided into
[0066] and
[0067]
[0068] exist Figure 5 The figure shows a velocity change curve with a velocity division between time t0 and t1. Here, we simplify and assume... The important thing here is not the speed during the shutdown phase. , The precise, constant variation curve in this embodiment. More specifically, it is important that the contact time t1 can be based on the time variation and relative position at the movement position z. Difference between time changes The difference was returned to zero after being re-probeed.
[0069]
[0070] Additionally, in the absence of an additional force sensing device, the closing force The contact time t1 can be determined as follows:
[0071]
[0072] The force acting between the connecting conductor 6 and the connecting member 7 during the establishment of the ultrasonic connection. Therefore, the bonding force at contact time t1 can be used to determine the bonding force. With closing force Determined by the difference between them:
[0073]
[0074] In a current embodiment of the operating method according to the invention, it is exemplarily assumed that the ultrasonic generating device 3 is movably held on the support relative to the support 2 by means of an elastic connecting element. Taking machine constants into consideration... In the case of offset (relative position) The force applied. Similarly, the force acting between the support 2 and the ultrasonic generating device 3 is not linear with respect to their relative positions. The determination is related to and / or time or velocity. Furthermore, the fixation of the ultrasonic generating device 3 on the support 2 can be performed via an actuator, allowing the bonding displacement force component to be variably adjusted or determined.
[0075] The same components and their functions are indicated by the same reference numerals.
Claims
1. A method for operating an ultrasonic connection device, wherein, The ultrasonic connection device is provided with an ultrasonic head (1) movable in the z-direction, the ultrasonic head is provided with a bracket (2), an ultrasonic generating device (3) movably held on the bracket (2) relative to the bracket (2), and an ultrasonic tool (4) that can be excited by the ultrasonic generating device (3) to vibrate ultrasonically. The method includes the following steps: —A conductive connecting conductor (6) is positioned above a conductively constructed connecting region (8) disposed on a connecting member (7), such that a gap (10) with a gap size (s) defined in the z direction is formed between the connecting conductor and the connecting surface (9) of the connecting region (8) facing the connecting conductor (6). — Position the ultrasonic head (1) relative to the connecting conductor (6) and the connecting member (7) such that the ultrasonic tool (4) is configured such that the contact surface (5) abutting the connecting conductor (6) faces the connecting conductor (6). —A bonding force acting in the z-direction is applied to the ultrasonic generating device (3). And press it against the support (2), Then —The ultrasonic head (1) is lowered in the z-direction, and the moving position (z) of the ultrasonic head (1) in the z-direction and the relative position of the ultrasonic generating device (3) with respect to the support (2) in the z-direction are determined. ),and —Considering the movement position (z) and the relative position (z) The contact time (t1) is determined in the case of the ultrasonic tool (4) descending to the extent that it contacts the connection area (8) of the connecting member (7).
2. The method according to claim 1, characterized in that, By determining the time change at the moving position (z) and the relative position (z), The contact time (t1) is determined by the difference (Δv) between the time changes of the two time values and by identifying the zero value of the difference (Δv).
3. The method according to claim 1 or 2, characterized in that, The bonding force ( The relative position of the ultrasonic generating device (3) with respect to the support (2) is determined. The function of ) and includes the relative position of the ultrasonic generating device (3) with respect to the support (2). The bond displacement force component of ).
4. The method according to claim 3, characterized in that, The bonding force ( The bonding fundamental force component applied to the ultrasonic head (1) consists of the bonding fundamental force component. The result is obtained by adding the bonding displacement force component to the given value.
5. The method according to claim 3, characterized in that, Give one aspect of the bonding force ( ) and / or the bonding displacement force component and the relative position of the ultrasonic generating device (3) with respect to the support (2) on the other hand The known correlations between them.
6. The method according to claim 3, characterized in that, Give one aspect of the bonding force ( ) and / or the bonding displacement force component and the relative position of the ultrasonic generating device (3) with respect to the support (2) on the other hand The known and linear correlation between them.
7. The method according to claim 3, characterized in that, The bonding displacement force component is applied and / or adjustable via an actuator.
8. The method according to claim 1 or 2, characterized in that, For the contact time (t1), determine the supporting force ( The ultrasonic generating device (3) is pressed against the bracket (2) by the supporting force.
9. The method according to claim 8, characterized in that, The supporting force was measured at least at the contact time (t1). ).
10. The method according to claim 8, characterized in that, The supporting force was measured at least at the contact time (t1) and continuously. ).
11. The method according to claim 1 or 2, characterized in that, For the contact time (t1), determine the closing force ( The closing force is applied to close the gap (10) between the connecting conductor (6) and the connecting member (7).
12. The method according to claim 4, characterized in that, For the contact time (t1), determine the closing force ( The closing force is applied to close the gap (10) between the connecting conductor (6) and the connecting member (7), and the closing force ( The bonding fundamental force component at the contact time (t1) is determined to be... The sum of the bonding displacement force components and the bonding displacement force components.
13. The method according to claim 8, characterized in that, The bonding force described in one aspect ( ) and on the other hand, the supporting force determined for the contact time (t1) ) and / or closing force ( The process force acting during the manufacture of the ultrasonic connection between the connecting conductor (6) and the connecting member (7) is determined. ).
14. The method according to claim 13, characterized in that, The process force ( ) is determined to be the bonding force ( ) and the closing force ( The difference between ).
15. The method according to claim 1 or 2, characterized in that, The relative position is detected by measurement technology. ) and / or the movement position (z).
16. The method according to claim 1 or 2, characterized in that, After the contact time (t1), the ultrasonic generating device (3) is activated and the ultrasonic tool (4) is excited to vibrate ultrasonically.
17. Application of the method according to any one of claims 1 to 16, wherein the method is used to electrically connect the load current connecting conductor (6) to the connection region (8) of the power electronic device structural assembly as a connecting member (7).