Potted Electronic Assemblies With CTE-Matched Fiber Reinforcement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional potting compounds exhibit high Coefficient of Thermal Expansion (CTE), leading to thermal stress issues and component failure in electronic assemblies under extreme mechanical and thermal loading, while low CTE compounds have high viscosity, making uniform application challenging.
Innovation Solution
Incorporation of CTE inhibiting additive fibers into the potting matrix, using custom-shaped fiber slugs to match the CTE of circuit boards, combined with a low viscosity resin for uniform impregnation and curing to create thermo-mechanically stable assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low CTE material additives are incorporated into the potting compound, then the CTE matching with circuit board is improved, but the viscosity increases making small features difficult to fill
Solution Approach 1:
The patent modifies the physical and chemical parameters of the potting compound by incorporating specific low CTE material additives (such as glass beads, ceramic particles, or fiber reinforcements) in controlled quantities. This changes the CTE parameter of the compound to match the circuit board while carefully controlling the compound's viscosity and flow characteristics to maintain fillability of small features.
Solution Approach 2:
The patent creates a composite potting compound by combining the base potting material with low CTE additives. This composite structure allows the compound to achieve the desired CTE matching properties while maintaining appropriate viscosity and flow characteristics for filling complex geometries and small features during the potting process.
2Reliability
If filled potting compounds are used to reduce CTE, then the CTE matching is improved, but the viscosity increases and fillers may be filtered out causing voids
Solution Approach 1:
The patent carefully controls the particle size distribution, shape, and concentration of the fillers to optimize both CTE matching and flow characteristics. By adjusting these parameters, the compound maintains low enough viscosity to fill small features completely while achieving the desired CTE reduction, preventing filler filtration and void formation.
Solution Approach 2:
The patent ensures uniform distribution of fillers throughout the potting compound by controlling the mixing process and filler characteristics. This local quality control prevents filler aggregation and filtration in specific areas, ensuring uniform properties throughout the cured potting compound and eliminating voids.
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 method produces electronic assemblies with uniform CTE matching that of the circuit boards, reducing thermal stress and ensuring structural integrity under extreme conditions.
Implementation Method 1
provide a potting compound having a first coefficient of thermal expansion different from a second coefficient of thermal expansion for a circuit board, provide a fiber reinforcement having a third coefficient of thermal expansion selected so that when the potting compound is combined with the fiber reinforcement the combined coefficient of thermal expansion is closer to the second coefficient of thermal expansion
Implementation Method 2
combined with a low viscosity resin for uniform impregnation
Data Source
AI summary
A method for manufacturing potted electronic assemblies are described. Embodiments of the method and system may provide a potting compound having a first coefficient of thermal expansion different from a second coefficient of thermal expansion for a circuit board, provide a fiber reinforcement having a third coefficient of thermal expansion selected so that when the potting compound is combined with the fiber reinforcement the combined coefficient of thermal expansion is closer to the second coefficient of thermal expansion than the first coefficient of thermal expansion is to the second coefficient of thermal expansion, and apply the fiber reinforcement and the potting compound to the circuit board.