Indium-Niobium Solder Column Structure for Cryogenic Thermal Stress
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Solution Overview
Problem
Existing solder columns face challenges in maintaining mechanical integrity and structural stability under extreme temperature fluctuations, particularly in cryogenic and elevated temperatures, leading to deformation, collapse, and CTE mismatch issues, which are exacerbated in extraterrestrial and quantum computing environments.
Innovation Solution
A solder column structure comprising an indium alloy core surrounded by a niobium alloy braided exoskeleton, designed to absorb thermal stresses and maintain structural integrity across a wide temperature range, using a braided structure to limit deformation at both cryogenic and elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If solder columns are made taller to absorb CTE differential thermal expansion, then compliance to absorb thermal stress is improved, but structural robustness to support load weight deteriorates
Solution Approach 1:
The patent uses a composite structure combining indium core material with niobium cladding material. The indium provides compliance and ductility to absorb CTE differential thermal expansion, while the niobium provides structural strength and rigidity to support the load weight of heavy CGA substrates. This composite approach resolves the contradiction by integrating materials with complementary properties into a single functional component.
Solution Approach 2:
The patent applies different material properties to different regions of the solder column. The core region uses indium for compliance and thermal expansion absorption, while the outer cladding region uses niobium for structural strength and load bearing. This spatial differentiation of material qualities allows the single solder column to simultaneously achieve both compliance and structural robustness.
2Strength
If solder column diameter is increased to improve structural robustness, then load support capability is improved, but pitch constraint compatibility deteriorates
Solution Approach 1:
The composite indium-niobium structure allows achieving high structural robustness with a smaller overall diameter. The niobium cladding provides exceptional strength-to-weight ratio, enabling the solder column to support heavy loads while maintaining a compact diameter that fits within the pitch constraints of fine-pitch CGA packages.
3Ease of manufacture
If conventional solder materials are used, then ease of manufacture is improved, but mechanical integrity at cryogenic temperatures deteriorates
Solution Approach 1:
The patent changes the material parameters by selecting indium and niobium alloys with specific compositional ranges and physical properties suitable for cryogenic operation. The indium core (50-99.9 wt%) and niobium cladding (1-50 wt%) are chosen for their low-temperature ductility and superconducting properties, maintaining mechanical integrity at cryogenic temperatures while remaining manufacturable through conventional soldering processes.
4Adaptability or versatility
If solder column material is made softer to improve compliance, then ability to absorb thermal stress is improved, but resistance to deformation at elevated temperatures deteriorates
Solution Approach 1:
The indium-niobium composite structure resolves this contradiction by assigning different functional roles to each material. The indium core remains soft and compliant for thermal stress absorption, while the niobium cladding provides high-temperature strength and deformation resistance. The combination allows the solder column to exhibit both compliance and thermal stability simultaneously.
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
The indium-niobium solder column provides mechanical compliance and electrical conductivity, ensuring reliable interconnects in harsh environments by preventing collapse and maintaining electrical performance across extreme temperature variations.
Implementation Method 1
absorb thermal stresses and maintain structural integrity across a wide temperature range
Implementation Method 2
operated at temperatures below the superconductivity point where the resistance of certain materials drops to zero allowing current to flow without energy loss
Data Source
AI summary
A method for making a superconducting, electrically conductive solder column that is mechanically compliant and capable of operating at low cryogenic temperatures for quantum computing and AI computing in datacenters and at elevated temperatures for applications found in extraterrestrial space exploration. The solder column can have an indium alloy core and a surface covered by a braided structure comprising a plurality of small diameter niobium wires coated with a thin layer of indium-alloy. The niobium braided structure can limit deformation of the indium alloy core when the solder column structure is subjected to elevated temperatures exceeding a liquidus temperature of the indium alloy core during the coating process and during post-manufacturing operations. The braided niobium wires can limit the deformation of the indium alloy core when the column structure falls below the ductile to brittle transition temperature during exposure to low cryogenic temperatures.