TCB Bond Head Compensation for Thermal Contact Misalignment
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Solution Overview
Problem
Thermal expansion during thermocompression bonding (TCB) processes leads to misalignment issues between IC device contacts and substrate contacts due to disproportionate expansion and thermal drift, especially when the substrate is larger than the bond head device, causing misalignment and potential solder bridging.
Innovation Solution
Implementing a dynamic thermal displacement compensation system using position detectors to monitor substrate edges and corners, tracking displacement vectors in both X and Y directions, and adjusting the bond head position in real-time to compensate for thermal expansion and contraction, allowing for tighter pitch bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermocompression bonding is performed at high temperature to achieve strong bonding, then bonding strength is improved, but thermal expansion causes misalignment between contacts
Solution Approach 1:
The system performs preliminary actions by detecting substrate edge positions before bonding occurs and calculating expected thermal displacement vectors. The bond head position is pre-adjusted based on these calculations, so when thermal expansion occurs during heating, the contacts remain properly aligned. This preliminary detection and calculation eliminates the misalignment problem that would otherwise occur during high-temperature bonding.
Solution Approach 2:
The system implements feedback by using position detectors to continuously monitor substrate edge positions during the bonding process. The detected positions are fed back to the control circuit, which calculates real-time displacement vectors and adjusts the bond head position accordingly. This closed-loop feedback ensures that contact alignment is maintained throughout the thermal bonding process, resolving the contradiction between high temperature bonding and alignment precision.
2Reliability
If the substrate is heated to bonding temperature, then bonding capability is improved, but thermal drift causes displacement between device and substrate contacts
Solution Approach 1:
The system replaces the traditional mechanical alignment approach with an optical/electromagnetic detection system. Position detectors using optical or electromagnetic fields monitor substrate edge positions and calculate thermal displacement vectors. The control circuit processes this information and electronically adjusts the bond head position, substituting mechanical trial-and-error alignment with precise field-based detection and electronic control, thereby maintaining contact accuracy during thermal drift.
Solution Approach 2:
The system changes the parameter being controlled from fixed mechanical position to dynamically adjustable position based on thermal displacement vectors. The control circuit calculates the displacement vector components (dx, dy) from detected substrate edge positions and adjusts the bond head position parameters accordingly. This parameter change allows the system to adapt to thermal expansion and maintain contact alignment throughout the bonding process.
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
Reduces misalignment during TCB by dynamically adjusting the bond head position based on monitored substrate displacement, enabling tighter pitch bonding and minimizing solder bridging, particularly in composite die bonding processes.
Implementation Method 1
substrate expansion during bonding can result in a misalignment between an IC devices contacts and those from the substrate
Implementation Method 2
tracking displacement vectors in both X and Y directions, and adjusting the bond head position in real-time to compensate for thermal expansion and contraction
Implementation Method 3
bring the associated metal contact surfaces into intimate atomic contact with each other and enable diffusion processes to merge them together
Data Source
Figure 1A~1D
Figure 2A
Figure 2B~4B
AI summary
In some embodiments, methods and apparatuses for performing thermal compression bonding and compensating for thermal displacement are provided.