Embedded Microjet Arrays for RF Device Thermal Management
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Solution Overview
Problem
Existing thermal management systems for heat-generating electronic components, such as RF devices, face limitations due to high conductive and convective thermal resistance, reliance on SWaP-constraining heat sinks, and inefficiencies in heat transfer, which restrict component lifetime, power output, and duty cycle.
Innovation Solution
A microjet array thermal management system is integrated directly onto the semiconductor substrate, utilizing a jet plate with microjets and an exhaust port to direct a single-phase coolant fluid for enhanced heat transfer, eliminating the need for low-conductance thermal interface materials and reducing SWaP constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing thermal management systems (finned heat sinks, cold plates, microchannels) are used, then heat dissipation is achieved, but conductive and convective thermal resistance increases and heat transfer efficiency decreases
Solution Approach 1:
The patent merges the thermal management system directly with the semiconductor substrate by integrating microjet arrays into the substrate structure itself, eliminating the need for separate heat sinks, thermal interface materials, and complex heat transfer pathways. This integration reduces both conductive and convective thermal resistance while improving heat transfer efficiency.
Solution Approach 2:
The patent extracts and eliminates thermal interface materials (TIMs) from the heat transfer pathway, which are identified as sources of thermal resistance. By directly bonding the jet plate to the substrate and using microjet impingement, the system removes the TIM layer that degrades heat transfer performance.
2Reliability
If thermal interface material is used between component and thermal management system, then heat transfer is facilitated, but thermal resistance increases and efficiency decreases
Solution Approach 1:
The patent removes thermal interface materials from the heat transfer pathway by directly bonding the jet plate to the semiconductor substrate. The microjet impingement system creates direct fluid-to-substrate heat transfer, eliminating the TIM layer that introduces thermal resistance and reduces efficiency.
3Volume of moving object
If compact system design is implemented, then SWaP constraints are satisfied, but ability to transfer heat to cooler ambient location is limited
Solution Approach 1:
The patent combines the cooling function directly into the semiconductor substrate by integrating microjet arrays within the substrate structure. This eliminates the need for external heat sinks and ambient heat transfer pathways, achieving effective heat removal in a compact form factor that satisfies SWaP constraints.
Solution Approach 2:
The patent transitions from external/ambient heat transfer to internal/integrated heat transfer by embedding microjet arrays within the substrate. This dimensional reorganization allows heat to be removed directly at the heat generation site without requiring external heat sinks or long thermal pathways.
4Power
If maximum power output is increased, then device performance improves, but maximum component temperature increases and lifetime decreases
Solution Approach 1:
The patent implements preliminary cooling action by positioning microjet arrays directly at the heat generation site within the substrate. The coolant jets impinge on the substrate surface before heat can accumulate and raise component temperature, enabling high power operation while maintaining safe operating temperatures and extending device lifetime.
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 solution significantly increases heat transfer coefficients, reduces peak device temperature, and enables higher power levels, longer component lifetime, and improved SWaP performance for RF devices across various environments by minimizing thermal resistance and integrating directly into the component fabrication process.
Implementation Method 1
the heat transfer from the surface of the semiconductor substrate to the thermal management system is a factor in determining the maximum component temperature. Thermal management systems usually conduct heat from the heat generating device into a spreader or heat sink. These systems then dissipate the heat to the ambient environment, such as via free convection, conduction, or radiation, or to a coolant, using forced convection.
Implementation Method 2
the conductive thermal resistance through the heat generating component itself is a factor in determining the maximum component temperature. The electrically active region of a heat generating device is typically located on one side of a semiconductor substrate, which may be, for example, silicon, gallium nitride, or gallium arsenide. This is the region where waste heat is generated. This heat must be conducted through the substrate before being dissipated through the thermal management system.
Data Source
AI summary
The present invention generally relates to a microjet array for use as a thermal management system for a heat generating device, such as an RF device. The microjet array is formed in a jet plate, which is attached directly to the substrate containing the heat generating device. Additional enhancing features are used to further improve the heat transfer coefficient above that inherently achieved by the array. Some of these enhancements may also have other functions, such as adding mechanical structure, electrical connectivity or pathways for waveguides. This technology enables higher duty cycles, higher power levels, increased component lifetime, and/or improved SWaP for RF devices operating in airborne, naval (surface and undersea), ground, and space environments. This technology serves as a replacement for existing RF device thermal management solutions, such as high-SWaP finned heat sinks and cold plates.