Ultrasonic Wire Bonding Vibration Damping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ultrasonic wire bonding methods face challenges in achieving consistent bond quality and reducing cycle time due to uncontrolled vibrations and inefficiencies in damping mechanisms, leading to scatter in process parameters and prolonged decay times.
Innovation Solution
The method involves passive and active damping of the transducer using resistive and inductive components, and counter-voltages to manage vibrations, allowing for real-time monitoring and adjustment of bonding process parameters, thereby reducing decay time and improving bond consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ultrasonic voltage is switched off after bonding, then the bonding process is completed, but the after-oscillation of the bonding tool prolongs the cycle time
Solution Approach 1:
The patent converts the harmful after-oscillation into a beneficial damping process by introducing active vibration control. The system uses sensors to detect the bonding tool's vibration and applies counter-voltages to the transducer to actively dampen the oscillations, transforming the problematic decay period into a controlled process that reduces overall cycle time.
Solution Approach 2:
The patent implements a feedback control system where sensors continuously monitor the bonding tool's vibration characteristics during and after the bonding process. This real-time feedback enables the control system to adjust the ultrasonic voltage dynamically, applying active damping to reduce after-oscillation and optimize the decay time, thereby improving productivity.
2Reliability
If the waiting time is increased to allow after-oscillation to subside, then the bond quality is maintained, but the cycle time increases
Solution Approach 1:
The patent applies periodic ultrasonic voltage with active damping during the bonding process and the subsequent decay period. By maintaining controlled periodic action rather than simply switching off the voltage, the system ensures consistent bond quality while actively managing the oscillation decay, thus reducing the required waiting time and improving cycle time without compromising bond reliability.
3Loss of time
If the transducer is actively damped with counter-voltage, then the decay time is reduced, but the device complexity increases
Solution Approach 1:
The patent implements a self-service control system where the ultrasonic wire bonder uses its own transducer and power supply to generate counter-voltages for active damping. The system monitors its own vibration characteristics and self-regulates the damping process, eliminating the need for external complex damping devices and making the complexity manageable within the existing equipment framework.
4Reliability
If the bonding process parameters are monitored during decay time, then the bond quality assessment is improved, but the measurement precision requirements increase
Solution Approach 1:
The patent uses feedback from sensors monitoring bonding process parameters during the decay period to assess bond quality. The active damping system adjusts the counter-voltage based on this feedback, and the same sensor data is used to evaluate bond characteristics. This dual-use of the feedback system allows for reliable quality assessment without requiring separate high-precision measurement systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces decay time by over 75%, enhances bond quality, and increases the number of bonds per unit time, making the process more cost-effective by minimizing scatter and optimizing bonding parameters.
Implementation Method 1
an ultrasonic transducer is now excited to oscillate in the ultrasonic range by means of a controller. The vibrations are transmitted to a bonding tool connected to the transducer
Implementation Method 2
Damping of the transducer takes place passively within the meaning of the invention. With passive damping, vibration energy is dissipated. For example, components with a dissipative effect are connected in series with the transducer for this purpose.
Implementation Method 3
The transducer can be actively damped, for example by applying a counter-voltage on the control side.
Implementation Method 4
the geometry of the bonding tool and the transducer is designed for the excitation in such a way that the bonding tool performs bending vibrations and an oscillation amplitude in the region of a tool tip
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a method for operating an ultrasonic wire bonder. The ultrasonic wire bonder has a bonding head with a bonding tool and with a transducer for exciting ultrasonic vibrations in the bonding tool and a controller (2) for the transducer (1). The method has a first process phase I, in which a bonding wire is bonded to a substrate, wherein the bonding wire is pressed against the substrate with a bonding force by means of a tool tip of the bonding tool, and the bonding tool is then excited so as to undergo ultrasonic vibrations in order to produce a bond between the bonding wire and the substrate, said transducer (1) being excited so as to vibrate for a specified or variable bonding time. In a subsequent second process phase II, the actuation of the transducer (1) is changed and reverberations of the bonding tool are counteracted, the transducer (1) being operated in a damped manner.