Cryogenic packaging for thermalization of low temperature devices
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Solution Overview
Problem
Existing cryogenic packaging for low temperature devices (LTDs) faces challenges in effective thermalization due to the poor thermal conductivity of substrate materials like silicon and sapphire at cryogenic temperatures, leading to inefficient heat dissipation and potential chip failure.
Innovation Solution
A cryogenic packaging system that includes a cover with a set of pillars and a chip with corresponding cavities, where the pillars and cavities are designed to thermally couple the chip to the cover, allowing for effective heat dissipation without the need to thin the chip, thereby maintaining its original thickness and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the chip is thinned to reduce substrate material, then thermalization efficiency is improved, but chip reliability and structural integrity deteriorate
Solution Approach 1:
The patent introduces an intermediary thermalization structure consisting of thermal vias and conductive layers that are integrated into the chip substrate. This mediator enables effective heat transfer from the device to the heat sink without requiring the chip to be thinned, thus maintaining both thermalization efficiency and chip reliability. The thermal vias act as conductive pathways that bridge the thermal gap between the device and the external heat sink.
2Loss of energy
If substrate material is reduced, then heat conduction path is shortened, but thermal contact stability deteriorates
Solution Approach 1:
The patent transitions from a single-point thermal contact to a distributed three-dimensional thermal conduction network. Multiple thermal vias are distributed throughout the chip substrate, creating parallel heat conduction pathways. This dimensional expansion from point-contact to distributed network maintains thermal contact stability while enabling efficient heat conduction through the full thickness of the chip.
3Device complexity
If the chip is thinned, then manufacturing complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent performs preliminary thermalization structure fabrication during the standard chip manufacturing process. Thermal vias and conductive layers are formed as part of the chip fabrication sequence, using established semiconductor manufacturing techniques. This preliminary integration eliminates the need for post-fabrication thinning and precision alignment operations, thereby reducing manufacturing complexity while maintaining precision through process integration.
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 enhances thermalization efficiency, reduces the risk of chip cracking, and maintains adequate thermal contact between the chip and the thermalization structure, even in fragile flip-chip configurations, leading to improved operation and reduced error rates in LTDs.
Implementation Method 1
a pillar from the set of pillars and corresponding to the cavity has a pillar profile such that the pillar profile causes the pillar to couple with the cavity of the cavity profile within a gap tolerance to thermally couple the chip to the cover for heat dissipation
Data Source
AI summary
A thermalization structure is formed using a cover configured with a set of pillars, the cover being a part of a cryogenic enclosure of a low temperature device (LTD). A chip including the LTD is configured with a set of cavities, a cavity in the set of cavities having a cavity profile. A pillar from the set of pillars and corresponding to the cavity has a pillar profile such that the pillar profile causes the pillar to couple with the cavity of the cavity profile within a gap tolerance to thermally couple the chip to the cover for heat dissipation in a cryogenic operation of the chip.