Wire Tail Adjustment in Wire Bonders
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Solution Overview
Problem
Inadequate wire tail formation during ball bonding operations in wire bonders leads to machine downtime and reduced productivity due to premature wire breakage or contamination, causing operational errors and the need for manual intervention.
Innovation Solution
A method involving a capillary and wire holding device to control and measure the wire tail length, ensuring it is of the appropriate length by paying out additional wire and using an EFO device to melt and form a molten ball, with mechanisms to address stuck wires and create new tails if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automatic wire tail adjustment is implemented, then productivity increases and machine downtime decreases, but device complexity increases
Solution Approach 1:
The wire tail adjustment mechanism is integrated within the existing wire bonding apparatus structure. The pay-out mechanism, wire clamp, and measurement systems are nested within the capillary assembly and wire feeding system, adding functionality without requiring a completely separate external system.
Solution Approach 2:
The system automatically detects wire tail length using optical sensors and autonomously adjusts the wire tail by paying out additional wire through the wire clamp mechanism. The EFO device automatically recuts the wire to the correct length, eliminating the need for manual intervention and operators to rethread the wire.
2Measurement precision
If manual intervention is required for wire tail issues, then measurement precision can be maintained, but loss of time increases
Solution Approach 1:
Optical measurement systems continuously monitor the wire tail length and provide feedback to the control system. When the wire tail becomes insufficient, the system automatically triggers the pay-out mechanism and EFO recutting process, maintaining precise wire tail length control without manual measurement or intervention.
Solution Approach 2:
Manual measurement and adjustment operations are replaced by an automated system combining optical sensors for measurement, motorized mechanisms for wire pay-out, and EFO (Electronic Flame-Off) for automatic wire recutting. This substitution eliminates manual intervention while maintaining measurement precision through automated optical detection.
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
Automatically prevents and recovers from inadequate wire tails, reducing downtime and increasing productivity by ensuring consistent wire tail lengths for subsequent bonding operations without human intervention.
Implementation Method 1
An EFO device will produce a spark to melt the wire tail to produce a molten ball
Implementation Method 2
The bonding force can lead to material deformation, breaking up of a contamination layer and smoothing out of surface asperity, which can be enhanced by the application of ultrasonic energy
Implementation Method 3
Heat can accelerate inter-atomic diffusion, thus forming the wire bond
Data Source
AI summary
A capillary is utilized to form the wedge wire bond comprised in a wire interconnection. A wire holding device is located above a wire clamp and the capillary to secure the wire while the wire clamp is open and not clamping onto the wire. The wire clamp and the capillary may be lifted relative to the wire in a direction away from the wedge wire bond and towards the wire holding device so as to pay out a length of wire from the capillary. At a predetermined height of the capillary, the wire clamp is closed to clamp onto the wire, and thereafter, the capillary and wire clamp may be moved further away from the wedge wire bond to cause the wire to break away from the wedge wire bond and to form the wire tail with a desired length extending from the capillary.