Wire Bond Foreign Particle Detection via Operating Characteristic Triggering
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Solution Overview
Problem
Existing wire bonding techniques face challenges in accurately detecting bonding failures, particularly due to foreign particles that can cause electrical shorting, which are often only detected during post-encapsulation testing, and current monitoring methods are time-consuming, reducing throughput.
Innovation Solution
A method that collects operating characteristics during wire bonding, such as energy consumption and wire deformation, to identify potential bonding failures, and captures images only when these characteristics indicate a suspect failure, using image processing to detect foreign particles, thereby improving detection accuracy and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If imaging is performed on every wire bond to detect foreign particles, then detection accuracy improves, but throughput decreases significantly
Solution Approach 1:
The patent applies partial action by performing imaging only on a subset of wire bonds that exhibit abnormal operating characteristics. Instead of imaging every bond, the system selectively images only those bonds where parameters such as bonding force, ultrasonic energy, or temperature deviate from expected ranges, thereby maintaining high detection accuracy for problematic bonds while preserving overall throughput.
Solution Approach 2:
The system uses feedback from real-time monitoring of operating characteristics during the bonding process to dynamically determine which bonds require imaging. When abnormal values are detected, the system triggers imaging for those specific bonds, creating a closed-loop quality control system that optimizes both detection accuracy and productivity.
2Productivity
If bonding monitoring is performed in real-time to detect failures immediately, then productivity improves by preventing wastage, but measurement precision requirements increase
Solution Approach 1:
The patent implements real-time feedback monitoring of bonding parameters including ultrasonic energy, bonding force, and temperature. This continuous feedback allows immediate detection of bonding failures without requiring post-bond imaging, thereby maintaining high throughput while achieving sufficient detection capability through multiple parameter correlation.
Solution Approach 2:
The system uses operating characteristics (bonding force, ultrasonic energy, temperature) as intermediary indicators to infer bonding quality. Rather than directly imaging every bond, these measurable parameters serve as proxies that indicate potential failures, enabling real-time detection with appropriate precision while maintaining productivity.
3Reliability
If existing monitoring methods are used to detect bonding failures, then some failures are detected, but classification of defects such as foreign bodies remains difficult
Solution Approach 1:
The patent uses operating characteristics as intermediary data that, when correlated with imaging results, enable classification of defect types. The combination of process parameters (force, energy, temperature) with visual inspection data allows the system to distinguish between different failure modes including foreign particle contamination, thereby improving reliability without excessive complexity.
Solution Approach 2:
The system merges multiple data sources including real-time bonding parameters, post-bond imaging data, and historical reference data to achieve comprehensive defect classification. This integration allows reliable identification of foreign bodies and other defects while managing system complexity through unified data processing.
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 allows for real-time identification of bonding defects due to foreign particles, reducing wastage and improving the overall efficiency of the wire bonding process by only imaging suspect bonds, thus enhancing the classification of bonding failures and increasing apparatus throughput.
Implementation Method 1
Motion of the wire is generated by an ultrasonic transducer excited by an ultrasonic generator to produce high-frequency mechanical vibrations
Implementation Method 2
The wire is pressed down with a small defined force, known as the bonding weight and the wire is deformed. This deformation is known as pre-deformation
Data Source
AI summary
A method of bonding wires onto surfaces, an apparatus and a computer program product are disclosed. The method of bonding wires onto surfaces, comprises the steps of: collecting operating characteristics of a bonding tool while forming a wire bond which bonds a wire to a surface; determining whether a possible bonding failure of the wire bond has occurred as indicated by the operating characteristics; and capturing an image of the wire bond to identify whether a foreign body is present on the surface if it is determined that a possible bonding failure has occurred. In this way, imaging of the wire bond is only necessary when the operating characteristics indicate a suspect bonding failure has occurred. This avoids the need to image every bond, while still imaging suspect bonds. This approach helps to significantly increase the throughput of the wire bonding apparatus whilst still identifying and classifying bonding defects due to the presence of a foreign body.