Wire Looping Method Using Bonding Tool Height Detection
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Solution Overview
Problem
Conventional methods for forming conductive bumps on wire bonding machines often result in premature separation of bonded balls from the wire, leading to potential short or long wire tail conditions and inadequate smoothing, which can cause errors in the wire looping process.
Innovation Solution
A method that involves forming a conductive bump by raising the bonding tool to a tail height with the wire clamp open, then lowering it to a smoothing height while keeping the clamp closed to establish a slack length of wire, which reduces the risk of premature separation and allows for stronger wire tails, and includes detecting the lift-off of conductive bumps during the wire looping process to prevent errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bonding tool is lowered to smooth the bonded ball surface, then the top surface quality improves, but the connection between bonded ball and wire weakens causing premature separation
Solution Approach 1:
The patent applies preliminary action by establishing the slack length of wire and positioning the bonding tool at tail height with the clamp open before the smoothing operation. This preparatory positioning ensures that when smoothing occurs with the clamp closed, the wire tail is already properly positioned and the connection strength is maintained while still achieving surface quality improvement.
2Reliability
If the wire clamp is kept open during smoothing, then premature separation is avoided, but wire tail length control becomes difficult
Solution Approach 1:
The patent uses preliminary action by positioning the bonding tool at tail height and establishing the slack length of wire before the smoothing operation begins. This ensures that when the clamp is closed during smoothing, the wire tail is already properly positioned and controlled, eliminating the need to keep the clamp open while still achieving reliable separation prevention.
3Productivity
If the bonding tool is raised to break the connection, then wire tail separation is achieved, but short or long wire tail conditions occur
Solution Approach 1:
The patent applies feedback by detecting the lift-off of conductive bumps during the wire looping process and using this information to control the bonding tool height and separation process. This feedback mechanism ensures that the bonding tool is raised to the precise height needed to break the connection at the optimal moment, achieving both efficient separation and precise wire tail length control without short or long tail conditions.
Data Source
AI summary
A method of forming a wire loop is provided. The method includes the steps of: (1) forming a conductive bump on a bonding location using a wire bonding tool; (2) bonding a portion of wire to another bonding location using the wire bonding tool; (3) extending a length of wire from the bonded portion of wire toward the bonding location; (4) lowering the bonding tool toward the bonding location while detecting a height of a tip of the wire bonding tool; and (5) interrupting the lowering of the wire bonding tool during step (4) if the wire bonding tool reaches a predetermined height.