Wire Bonding Recovery for NSOP, NSOL, and Short Tail Errors
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Solution Overview
Problem
Wire bonding machines face challenges such as 'no stick on pad' (NSOP) and 'no stick on lead' (NSOL) conditions, as well as short tail conditions, which can lead to inconsistent bond formation and require manual intervention for recovery.
Innovation Solution
Automated recovery methods are implemented in wire bonding machines, including bonding a free air ball to a second location after initial failure, weakening and separating the wire neck, and bending and rebonding the wire tail to ensure continuous operation without operator intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automated recovery methods are implemented to handle NSOP, NSOL, and short tail conditions, then productivity and reliability are improved, but device complexity increases
Solution Approach 1:
The wire bonding machine performs automatic recovery operations when NSOP, NSOL, or short tail conditions are detected. The system autonomously executes corrective actions including re-bonding free air balls to alternative locations, separating wire necks, and forming new free air balls without operator intervention, thereby maintaining high productivity while managing complexity through self-service automation
Solution Approach 2:
The control system dynamically adjusts bonding parameters such as ultrasonic energy, bond force, and temperature based on detected error conditions. By modifying these parameters adaptively during recovery operations, the system handles various error scenarios effectively while maintaining streamlined control architecture
2Manufacturing precision
If manual intervention is required for error recovery, then manufacturing precision can be maintained through operator judgment, but loss of time increases and productivity decreases
Solution Approach 1:
The system automatically detects bonding errors and executes recovery procedures without waiting for manual inspection or intervention. This self-service capability eliminates downtime while maintaining bond quality through programmed precision, directly resolving the trade-off between precision and time loss
Solution Approach 2:
The control system continuously monitors bonding outcomes and automatically initiates recovery actions when defects are detected. This closed-loop feedback mechanism ensures consistent bond quality by applying corrective actions immediately, preventing time loss while maintaining manufacturing precision through real-time quality control
3Reliability
If multiple bonding attempts are made to recover from errors, then reliability of bond formation improves, but use of energy and wire consumption increase
Solution Approach 1:
When a free air ball fails to bond to its intended location, the system extracts or separates the wire neck and repositions the free air ball to an alternative bonding location. This extraction approach allows retrying the bond with the same wire segment rather than consuming additional wire, thereby improving reliability while minimizing wire consumption
Solution Approach 2:
The system recovers wire segments that would otherwise be discarded due to bonding failures. By separating and repositioning wire necks with attached free air balls for alternative bonding locations, the system recovers valuable wire material and extends its useful life, reducing overall wire consumption while maintaining high bond formation success rates
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
These methods enable efficient automatic recovery from error conditions like NSOP, NSOL, and short tail situations, maintaining consistent bond quality and reducing manual intervention, thus enhancing the reliability and efficiency of wire bonding processes.
Implementation Method 1
varying types of bonding energy may be used, for example, ultrasonic energy
Implementation Method 2
a tail of wire extending from the tip of a bonding tool (e.g., a capillary) is melted into a free air ball using a spark from an electronic flame-off (EFO) device
Data Source
AI summary
A method of operating a wire bonding machine is provided. The method includes the steps of: (a) attempting to bond a free air ball to a first bonding location using a wire bonding tool; (b) detecting that the free air ball was not properly bonded to the first bonding location in step (a); (c) bonding the free air ball to a second bonding location; (d) raising the wire bonding tool, with a wire engaged with the wire bonding tool continuous with the bonded free air ball, to a position above the bonded free air ball; (e) weakening a neck portion of a wire above the free air ball after step (d); and (f) separating the bonded free air ball from the wire after step (e) such that a wire tail extends below a tip of a wire bonding tool.