Hermetic Electronics Module Lid Cooling for Core IC Heat Dissipation
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Solution Overview
Problem
Hermetically sealed electronic modules in space applications face challenges in heat dissipation due to the absence of air and the need for high reliability, which limits the use of traditional cooling methods and poses risks with existing heat extraction techniques that require direct bonding or penetration of the seal.
Innovation Solution
A heat spreader is bonded to the interior surface of the lid in a hermetically sealed module, extending over the core IC and using a thin layer of TIM for thermal interface, allowing efficient heat transfer without penetrating the seal or direct bonding to the IC, and is designed to avoid taller components within the module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional heat sinks and cooling fans are used, then heat dissipation is improved, but hermetic sealing cannot be maintained due to the absence of air in space and reliability requirements
Solution Approach 1:
The patent introduces a heat spreader as an intermediary component between the core IC and the lid. The heat spreader is hermetically sealed to the lid and extends downward to make thermal contact with the core IC, serving as a mediator that transfers heat from the sealed environment to the lid without compromising the hermetic seal. This resolves the contradiction by providing a thermal pathway while maintaining the integrity of the hermetic enclosure.
2Reliability
If the lid is raised above all internal components to ensure hermetic sealing, then sealing reliability is improved, but thermal contact with the core IC is reduced due to the gap filled by TIM
Solution Approach 1:
The heat spreader extends in the vertical dimension from the lid downward toward the core IC, creating a three-dimensional thermal conduction path. By adding this vertical extension, the patent achieves both hermetic sealing (lid above components) and effective heat conduction (heat spreader bridging the gap), transforming the two-dimensional gap problem into a three-dimensional thermal pathway.
3Reliability
If a thick layer of TIM is used to fill the gap between lid and core IC, then hermetic sealing is maintained, but heat conduction efficiency is insufficient
Solution Approach 1:
The patent employs a composite thermal management system combining the heat spreader material (high thermal conductivity) with TIM (sealing function). The heat spreader provides the primary thermal conduction pathway with superior heat transfer properties, while the TIM maintains hermetic sealing. This composite approach allows each material to optimize its primary function, resolving the contradiction between sealing and heat conduction.
4Temperature
If direct bonding or penetration of the seal is used for heat extraction, then heat dissipation is improved, but manufacturing complexity and thermal stress risks increase
Solution Approach 1:
The heat spreader is hermetically sealed to the lid before the lid is attached to the collar, forming a pre-assembled unit. This preliminary action simplifies the overall manufacturing process by pre-establishing the thermal pathway and hermetic seal, reducing the complexity of final assembly and minimizing thermal stress risks during manufacturing operations.
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 method effectively removes heat from the core IC within the sealed module without compromising the hermetic seal, reducing manufacturing complexity and thermal stress risks, while maintaining high reliability and efficiency in heat dissipation.
Implementation Method 1
A heat spreader is bonded to the interior surface of the lid in a hermetically sealed module, extending over the core IC and using a thin layer of TIM for thermal interface, allowing efficient heat transfer
Data Source
AI summary
A hermetically sealed electronics module includes a core IC installed on a substrate. A collar surrounds the core IC and is sealed to the substrate and to a lid, forming a sealed chamber. A heat spreader bonded to an internal surface of the lid extends downward into proximal thermal contact with the core IC. A thin layer of TIM can be applied between the heat spreader and core IC. The heat spreader does not overlap any tall components that extend above the core IC, and can extend over regions adjacent to the core IC. Tall components can be limited to a periphery of the chamber, and/or the heat spreader can include openings that surround central tall components. The heat spreader can be soldered or welded to the lid over an entire upper surface of the heat spreader. X-ray and/or CSAM scanning can detect heat spreader bonding flaws.