Wire Bonding Tension Control via Dynamic Gas Flow
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Solution Overview
Problem
Existing wire bonding apparatuses face challenges in maintaining suitable wire tension during the formation of wire loops, leading to issues such as excessive stretching or wire cutoff, and require additional maintenance and size compromises to prevent wire falling.
Innovation Solution
A wire bonding apparatus with a bonding arm, ultrasonic horn, and tensioners that control gas flows to apply tension, allowing for adjustable tension control post-first bonding step without the need for additional clamps, ensuring suitable loop formation without reducing processing speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second clamper is arranged above an existing clamper to prevent wire falling, then wire bonding reliability is improved, but device complexity and maintenance requirements increase
Solution Approach 1:
The gas flow rate is dynamically adjusted during the wire bonding process. The tensioning gas flow is set at a first flow rate during wire loop formation, then reduced to a second flow rate (lower than the first) during the bonding process to prevent wire falling without requiring additional mechanical clampers
Solution Approach 2:
Gas flow is used to apply tension to the wire instead of mechanical clampers. By controlling the gas flow rate through the tensioning gas flow supply unit, the wire tension can be adjusted to prevent wire falling during bonding while maintaining loop formation capability
2Reliability
If wire tension is increased to prevent wire falling, then wire bonding reliability is improved, but wire loop formation quality deteriorates due to excessive stretching
Solution Approach 1:
The gas flow rate is dynamically changed based on the bonding stage. During wire loop formation, a higher first flow rate provides sufficient tension without excessive stretching. During the bonding process, the flow rate is reduced to a lower second rate to prevent wire falling, thus maintaining both loop quality and bonding reliability
Solution Approach 2:
The tensioning gas flow rate parameter is changed between two distinct values: a first flow rate for loop formation and a second flow rate for bonding. This parameter change allows optimization of wire tension for each specific bonding stage, preventing both excessive stretching and wire falling
3Reliability
If additional clamps are added to control wire tension, then wire bonding reliability is improved, but device size increases
Solution Approach 1:
A gas flow-based tensioning system is used instead of additional mechanical clampers. The tensioning gas flow supply unit delivers gas to the existing clamper to provide wire tension, eliminating the need for separate mechanical tensioning devices and reducing overall device size
Solution Approach 2:
The existing clamper structure serves dual functions: mechanical support for the wire and tensioning element through gas flow application. This multi-functionality eliminates the need for separate tensioning devices, maintaining wire bonding reliability while reducing device complexity and size
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
Enables good wire bonding with improved maintainability and size reduction by controlling gas flows to manage wire tension effectively, preventing excessive stretching and wire cutoff, and eliminating the need for separate clamps.
Implementation Method 1
a first tensioner which forms, nearer the wire supply side than the bonding tool, a first gas flow for applying a tension toward the wire supply side on the wire
Implementation Method 2
a second tensioner which forms, between the first tensioner and the pressing part of the bonding tool, a second gas flow for applying a tension toward the wire supply side on the wire
Implementation Method 3
an ultrasonic horn attached to a front end of the bonding arm; a bonding tool attached to one end of the ultrasonic horn
Data Source
AI summary
A wire bonding apparatus includes: a first tensioner which forms, nearer a wire supply side than a bonding tool, a first gas flow for applying a tension toward the wire supply side on a wire; a second tensioner which forms, between the first tensioner and a pressing part of the bonding tool, a second gas flow for applying a tension toward the wire supply side on the wire; and a control part which controls the first tensioner and the second tensioner. The control part implements control, in a predetermined period after a first bonding step for bonding the wire to a first bonding point, to turn off at least the second gas flow of the second tensioner among the first tensioner and the second tensioner or to make at least the second gas flow smaller than in the first bonding step.