Micro-Channel Air Impingement Cooling for Uniform Bonding
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Solution Overview
Problem
Thermal compression bonding processes in the microelectronic industry face challenges in achieving quick and uniform cooling of solder joints, leading to prolonged process times due to low heat transfer coefficients in existing cooling systems, which restrict the formation of high-quality first-level interconnects.
Innovation Solution
The implementation of a direct air impingement cooling system utilizing micro-channel structures and micro jets, where incoming and outgoing jets are arranged to minimize flow interactions and maintain a thin thermal boundary layer, enhancing the heat transfer coefficient and cooling rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional cooling systems are used, then the structure is simple, but the heat transfer coefficient is low and cooling time is prolonged
Solution Approach 1:
The cooling system is segmented into multiple micro-channels and micro-jets arranged in an array, dividing the cooling function into numerous small-scale flow paths that individually impinge on the heater surface, thereby increasing overall heat transfer efficiency while managing system complexity through modular design
Solution Approach 2:
The cooling approach transitions from conventional macro-scale cooling to micro-scale cooling by implementing micro-channels and micro-jets, adding a dimensional scale transformation that significantly enhances the heat transfer coefficient and reduces cooling time
2Speed
If higher fluid pressure is applied, then cooling rate increases, but tool vibrations increase
Solution Approach 1:
The system utilizes pneumatic principles by employing compressed gas (air or nitrogen) flowing through micro-channels and exiting as micro-jets, leveraging gas dynamics to achieve high cooling rates while the distributed jet array design mitigates vibration through dispersed force distribution
3Manufacturing precision
If jets are arranged closely, then cooling uniformity improves, but flow interactions increase and reduce effectiveness
Solution Approach 1:
The micro-jet array is designed with locally optimized jet spacing and orientation, where each jet is positioned to create a thin thermal boundary layer on the heater surface, achieving uniform cooling through localized flow control while managing interactions through precise geometric arrangement
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 significantly reduces the cooling time of solder joints by achieving a heat transfer coefficient of up to 3000 W/m2K, resulting in a 60% reduction in process time and enabling faster bonding, while operating at lower fluid pressures to minimize tool vibrations and increase throughput.
Implementation Method 1
Fluid that may flow through the array of micro channel jets 102 may impinge on the hot surface of the heater plate 109
Implementation Method 2
The heat may then be circulated away away/transferred into an adjacent outgoing micro jet channel 107
Implementation Method 3
thus keeping the thermal boundary layer very thin
Implementation Method 4
Fluid that may flow through the array of micro channel jets 102 may impinge on the hot surface of the heater plate 109, and then may pick up the heat from the heater plate 109
Data Source
AI summary
Various embodiments of thermal compression bonding transient cooling solutions are described. Those embodiments include a an array of vertically separated micro channels coupled to a heater surface, wherein every outlet micro channel comprises two adjacent inlet micro channel, and wherein an inlet and outlet manifold are coupled to the array of micro channels, and wherein the heater surface and the micro channels are coupled within the same block.