Bonding Tool Position Control for Solder Deformation
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Solution Overview
Problem
In electronic component mounting, the thin solder film on copper substrates is prone to deformation due to the sinkage of thermal bonding tools, leading to poor bonding quality and potential damage to components, especially when gold bumps come into contact with copper electrodes during thermal fusion bonding.
Innovation Solution
An electronic component mounting apparatus with a bonding tool that uses position detection and control units to maintain a predetermined distance and pressure, transitioning from constant loading to position holding once the solder is fused, ensuring the gold bump remains within the solder film without deforming or contacting adjacent bumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thermal bonding tool is fixed before melting the solder bump to avoid deforming the solder, then the position stability is improved, but the tool may still move downward due to load cell residual deformation and squash the melted solder
Solution Approach 1:
The patent employs a load cell to detect pressing force in real-time and provides feedback to the control unit. The control unit monitors the pressing force and detects when solder melting occurs through the change in loading, enabling dynamic adjustment of the bonding tool position to prevent both premature movement and excessive sinking that would deform the solder bump
Solution Approach 2:
The patent transitions from a static fixed-position approach to a dynamic control system that continuously adjusts the bonding tool position based on real-time pressing force detection. The system dynamically switches between position control and constant loading control modes to optimize bonding quality while preventing solder deformation
2Manufacturing precision
If the thermal bonding tool is brought to have reduced pressing force before solder bump melting to prevent deformation, then the solder bump integrity is improved, but the tool sink after loading decreases can exceed the solder film thickness and cause gold bump contact with copper electrode
Solution Approach 1:
The load cell provides real-time feedback on pressing force, allowing the control unit to detect the precise moment when solder melting occurs through loading reduction. This enables the system to switch from constant loading control to position control at the optimal moment, preventing the bonding tool from sinking too far and damaging the gold bump while ensuring complete solder fusion
Solution Approach 2:
The patent changes the control parameter from constant position to constant loading during the heating phase, then switches back to position control when solder melting is detected. This parameter change allows the bonding tool to maintain reduced pressing force during critical phases while preventing excessive sink that would damage the gold bump
3Reliability
If constant loading control is used after starting to increase temperature to reliably control bonding, then the bonding process stability is improved, but the tool sink can exceed solder film thickness and cause poor bonding quality
Solution Approach 1:
The control unit continuously monitors the load cell output during constant loading control and detects the precise moment when solder melting occurs through loading reduction. This feedback mechanism enables timely switching to position control, preventing the bonding tool from sinking beyond the solder film thickness and ensuring high bonding quality while maintaining process stability
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 improves bonding quality by preventing deformation and ensuring accurate positioning, thereby enhancing the reliability of the thermal fusion bonding process between gold bumps and copper electrodes.
Implementation Method 1
the electronic component is pressed against the substrate using a bonding tool and heated to melt the solder bump for solder bond
Implementation Method 2
there is still deformation due to loading in a load cell for detecting a pressing force
Data Source
AI summary
An electronic component mounting apparatus includes a bonding tool for thermally bonding an electronic component onto a substrate, the bonding tool to be driven in a direction getting close to and from the substrate, a linear scale and a linear scale head detecting the position of the bonding tool in the direction getting close to and from the substrate, and a control unit configured to hold the position of the bonding tool in the direction getting close to and from the substrate when a solder film between an electrode of the electronic component and an electrode of the substrate is thermally fused when the bonding tool gets close to the substrate by a predetermined distance from a reference position while heating the electronic component. The electronic component mounting apparatus for bonding the electronic component and the substrate with thermally fusible bond metal offers an improvement in the bonding quality.